[PATCH v8 17/31] rust: add `kernel` crate

From: Miguel Ojeda
Date: Mon Aug 01 2022 - 21:54:15 EST

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From: Wedson Almeida Filho <wedsonaf@xxxxxxxxxx>

The `kernel` crate currently includes all the abstractions that wrap
kernel features written in C.

These abstractions call the C side of the kernel via the generated
bindings with the `bindgen` tool. Modules developed in Rust should
never call the bindings themselves.

In the future, as the abstractions grow in number, we may need
to split this crate into several, possibly following a similar
subdivision in subsystems as the kernel itself and/or moving
the code to the actual subsystems.

Co-developed-by: Alex Gaynor <alex.gaynor@xxxxxxxxx>
Signed-off-by: Alex Gaynor <alex.gaynor@xxxxxxxxx>
Co-developed-by: Geoffrey Thomas <geofft@xxxxxxxxxxxxx>
Signed-off-by: Geoffrey Thomas <geofft@xxxxxxxxxxxxx>
Co-developed-by: Finn Behrens <me@xxxxxxxxx>
Signed-off-by: Finn Behrens <me@xxxxxxxxx>
Co-developed-by: Adam Bratschi-Kaye <ark.email@xxxxxxxxx>
Signed-off-by: Adam Bratschi-Kaye <ark.email@xxxxxxxxx>
Co-developed-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Co-developed-by: Sumera Priyadarsini <sylphrenadin@xxxxxxxxx>
Signed-off-by: Sumera Priyadarsini <sylphrenadin@xxxxxxxxx>
Co-developed-by: Sven Van Asbroeck <thesven73@xxxxxxxxx>
Signed-off-by: Sven Van Asbroeck <thesven73@xxxxxxxxx>
Co-developed-by: Gary Guo <gary@xxxxxxxxxxx>
Signed-off-by: Gary Guo <gary@xxxxxxxxxxx>
Co-developed-by: Boris-Chengbiao Zhou <bobo1239@xxxxxx>
Signed-off-by: Boris-Chengbiao Zhou <bobo1239@xxxxxx>
Co-developed-by: Boqun Feng <boqun.feng@xxxxxxxxx>
Signed-off-by: Boqun Feng <boqun.feng@xxxxxxxxx>
Co-developed-by: Fox Chen <foxhlchen@xxxxxxxxx>
Signed-off-by: Fox Chen <foxhlchen@xxxxxxxxx>
Co-developed-by: Dan Robertson <daniel.robertson@xxxxxxxxxx>
Signed-off-by: Dan Robertson <daniel.robertson@xxxxxxxxxx>
Co-developed-by: Viktor Garske <viktor@xxxxxxxx>
Signed-off-by: Viktor Garske <viktor@xxxxxxxx>
Co-developed-by: Dariusz Sosnowski <dsosnowski@xxxxxxxxxxxxx>
Signed-off-by: Dariusz Sosnowski <dsosnowski@xxxxxxxxxxxxx>
Co-developed-by: Léo Lanteri Thauvin <leseulartichaut@xxxxxxxxx>
Signed-off-by: Léo Lanteri Thauvin <leseulartichaut@xxxxxxxxx>
Co-developed-by: Niklas Mohrin <dev@xxxxxxxxxxxxxxx>
Signed-off-by: Niklas Mohrin <dev@xxxxxxxxxxxxxxx>
Co-developed-by: Gioh Kim <gurugio@xxxxxxxxx>
Signed-off-by: Gioh Kim <gurugio@xxxxxxxxx>
Co-developed-by: Daniel Xu <dxu@xxxxxxxxx>
Signed-off-by: Daniel Xu <dxu@xxxxxxxxx>
Co-developed-by: Milan Landaverde <milan@xxxxxxxxxxxx>
Signed-off-by: Milan Landaverde <milan@xxxxxxxxxxxx>
Co-developed-by: Morgan Bartlett <mjmouse9999@xxxxxxxxx>
Signed-off-by: Morgan Bartlett <mjmouse9999@xxxxxxxxx>
Co-developed-by: Maciej Falkowski <m.falkowski@xxxxxxxxxxx>
Signed-off-by: Maciej Falkowski <m.falkowski@xxxxxxxxxxx>
Co-developed-by: Jiapeng Chong <jiapeng.chong@xxxxxxxxxxxxxxxxx>
Signed-off-by: Jiapeng Chong <jiapeng.chong@xxxxxxxxxxxxxxxxx>
Co-developed-by: Nándor István Krácser <bonifaido@xxxxxxxxx>
Signed-off-by: Nándor István Krácser <bonifaido@xxxxxxxxx>
Co-developed-by: David Gow <davidgow@xxxxxxxxxx>
Signed-off-by: David Gow <davidgow@xxxxxxxxxx>
Co-developed-by: John Baublitz <john.m.baublitz@xxxxxxxxx>
Signed-off-by: John Baublitz <john.m.baublitz@xxxxxxxxx>
Co-developed-by: Björn Roy Baron <bjorn3_gh@xxxxxxxxxxxxxx>
Signed-off-by: Björn Roy Baron <bjorn3_gh@xxxxxxxxxxxxxx>
Signed-off-by: Wedson Almeida Filho <wedsonaf@xxxxxxxxxx>
Co-developed-by: Miguel Ojeda <ojeda@xxxxxxxxxx>
Signed-off-by: Miguel Ojeda <ojeda@xxxxxxxxxx>
---
rust/kernel/allocator.rs | 64 ++
rust/kernel/amba.rs | 261 +++++++
rust/kernel/build_assert.rs | 83 +++
rust/kernel/chrdev.rs | 206 ++++++
rust/kernel/clk.rs | 79 ++
rust/kernel/cred.rs | 46 ++
rust/kernel/delay.rs | 104 +++
rust/kernel/device.rs | 527 ++++++++++++++
rust/kernel/driver.rs | 442 +++++++++++
rust/kernel/error.rs | 564 ++++++++++++++
rust/kernel/file.rs | 887 +++++++++++++++++++++++
rust/kernel/fs.rs | 846 +++++++++++++++++++++
rust/kernel/fs/param.rs | 553 ++++++++++++++
rust/kernel/gpio.rs | 505 +++++++++++++
rust/kernel/hwrng.rs | 210 ++++++
rust/kernel/io_buffer.rs | 153 ++++
rust/kernel/io_mem.rs | 278 +++++++
rust/kernel/iov_iter.rs | 81 +++
rust/kernel/irq.rs | 681 +++++++++++++++++
rust/kernel/kasync.rs | 50 ++
rust/kernel/kasync/executor.rs | 154 ++++
rust/kernel/kasync/executor/workqueue.rs | 291 ++++++++
rust/kernel/kasync/net.rs | 322 ++++++++
rust/kernel/kunit.rs | 91 +++
rust/kernel/lib.rs | 267 +++++++
rust/kernel/linked_list.rs | 247 +++++++
rust/kernel/miscdev.rs | 290 ++++++++
rust/kernel/mm.rs | 149 ++++
rust/kernel/module_param.rs | 499 +++++++++++++
rust/kernel/net.rs | 392 ++++++++++
rust/kernel/net/filter.rs | 447 ++++++++++++
rust/kernel/of.rs | 63 ++
rust/kernel/pages.rs | 144 ++++
rust/kernel/platform.rs | 223 ++++++
rust/kernel/power.rs | 118 +++
rust/kernel/prelude.rs | 36 +
rust/kernel/print.rs | 406 +++++++++++
rust/kernel/random.rs | 42 ++
rust/kernel/raw_list.rs | 361 +++++++++
rust/kernel/rbtree.rs | 563 ++++++++++++++
rust/kernel/revocable.rs | 425 +++++++++++
rust/kernel/security.rs | 38 +
rust/kernel/static_assert.rs | 34 +
rust/kernel/std_vendor.rs | 161 ++++
rust/kernel/str.rs | 597 +++++++++++++++
rust/kernel/sync.rs | 48 +-
rust/kernel/sysctl.rs | 199 +++++
rust/kernel/task.rs | 239 ++++++
rust/kernel/types.rs | 705 ++++++++++++++++++
rust/kernel/unsafe_list.rs | 680 +++++++++++++++++
rust/kernel/user_ptr.rs | 175 +++++
rust/kernel/workqueue.rs | 512 +++++++++++++
52 files changed, 15518 insertions(+), 20 deletions(-)
create mode 100644 rust/kernel/allocator.rs
create mode 100644 rust/kernel/amba.rs
create mode 100644 rust/kernel/build_assert.rs
create mode 100644 rust/kernel/chrdev.rs
create mode 100644 rust/kernel/clk.rs
create mode 100644 rust/kernel/cred.rs
create mode 100644 rust/kernel/delay.rs
create mode 100644 rust/kernel/device.rs
create mode 100644 rust/kernel/driver.rs
create mode 100644 rust/kernel/error.rs
create mode 100644 rust/kernel/file.rs
create mode 100644 rust/kernel/fs.rs
create mode 100644 rust/kernel/fs/param.rs
create mode 100644 rust/kernel/gpio.rs
create mode 100644 rust/kernel/hwrng.rs
create mode 100644 rust/kernel/io_buffer.rs
create mode 100644 rust/kernel/io_mem.rs
create mode 100644 rust/kernel/iov_iter.rs
create mode 100644 rust/kernel/irq.rs
create mode 100644 rust/kernel/kasync.rs
create mode 100644 rust/kernel/kasync/executor.rs
create mode 100644 rust/kernel/kasync/executor/workqueue.rs
create mode 100644 rust/kernel/kasync/net.rs
create mode 100644 rust/kernel/kunit.rs
create mode 100644 rust/kernel/lib.rs
create mode 100644 rust/kernel/linked_list.rs
create mode 100644 rust/kernel/miscdev.rs
create mode 100644 rust/kernel/mm.rs
create mode 100644 rust/kernel/module_param.rs
create mode 100644 rust/kernel/net.rs
create mode 100644 rust/kernel/net/filter.rs
create mode 100644 rust/kernel/of.rs
create mode 100644 rust/kernel/pages.rs
create mode 100644 rust/kernel/platform.rs
create mode 100644 rust/kernel/power.rs
create mode 100644 rust/kernel/prelude.rs
create mode 100644 rust/kernel/print.rs
create mode 100644 rust/kernel/random.rs
create mode 100644 rust/kernel/raw_list.rs
create mode 100644 rust/kernel/rbtree.rs
create mode 100644 rust/kernel/revocable.rs
create mode 100644 rust/kernel/security.rs
create mode 100644 rust/kernel/static_assert.rs
create mode 100644 rust/kernel/std_vendor.rs
create mode 100644 rust/kernel/str.rs
create mode 100644 rust/kernel/sysctl.rs
create mode 100644 rust/kernel/task.rs
create mode 100644 rust/kernel/types.rs
create mode 100644 rust/kernel/unsafe_list.rs
create mode 100644 rust/kernel/user_ptr.rs
create mode 100644 rust/kernel/workqueue.rs

diff --git a/rust/kernel/allocator.rs b/rust/kernel/allocator.rs
new file mode 100644
index 000000000000..397a3dd57a9b
--- /dev/null
+++ b/rust/kernel/allocator.rs
@@ -0,0 +1,64 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Allocator support.
+
+use core::alloc::{GlobalAlloc, Layout};
+use core::ptr;
+
+use crate::bindings;
+
+struct KernelAllocator;
+
+unsafe impl GlobalAlloc for KernelAllocator {
+ unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
+ // `krealloc()` is used instead of `kmalloc()` because the latter is
+ // an inline function and cannot be bound to as a result.
+ unsafe { bindings::krealloc(ptr::null(), layout.size(), bindings::GFP_KERNEL) as *mut u8 }
+ }
+
+ unsafe fn dealloc(&self, ptr: *mut u8, _layout: Layout) {
+ unsafe {
+ bindings::kfree(ptr as *const core::ffi::c_void);
+ }
+ }
+}
+
+#[global_allocator]
+static ALLOCATOR: KernelAllocator = KernelAllocator;
+
+// `rustc` only generates these for some crate types. Even then, we would need
+// to extract the object file that has them from the archive. For the moment,
+// let's generate them ourselves instead.
+//
+// Note that `#[no_mangle]` implies exported too, nowadays.
+#[no_mangle]
+fn __rust_alloc(size: usize, _align: usize) -> *mut u8 {
+ unsafe { bindings::krealloc(core::ptr::null(), size, bindings::GFP_KERNEL) as *mut u8 }
+}
+
+#[no_mangle]
+fn __rust_dealloc(ptr: *mut u8, _size: usize, _align: usize) {
+ unsafe { bindings::kfree(ptr as *const core::ffi::c_void) };
+}
+
+#[no_mangle]
+fn __rust_realloc(ptr: *mut u8, _old_size: usize, _align: usize, new_size: usize) -> *mut u8 {
+ unsafe {
+ bindings::krealloc(
+ ptr as *const core::ffi::c_void,
+ new_size,
+ bindings::GFP_KERNEL,
+ ) as *mut u8
+ }
+}
+
+#[no_mangle]
+fn __rust_alloc_zeroed(size: usize, _align: usize) -> *mut u8 {
+ unsafe {
+ bindings::krealloc(
+ core::ptr::null(),
+ size,
+ bindings::GFP_KERNEL | bindings::__GFP_ZERO,
+ ) as *mut u8
+ }
+}
diff --git a/rust/kernel/amba.rs b/rust/kernel/amba.rs
new file mode 100644
index 000000000000..ec8808124a29
--- /dev/null
+++ b/rust/kernel/amba.rs
@@ -0,0 +1,261 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Amba devices and drivers.
+//!
+//! C header: [`include/linux/amba/bus.h`](../../../../include/linux/amba/bus.h)
+
+use crate::{
+ bindings, device, driver, error::from_kernel_result, io_mem::Resource, power, str::CStr,
+ to_result, types::PointerWrapper, Result, ThisModule,
+};
+
+/// A registration of an amba driver.
+pub type Registration<T> = driver::Registration<Adapter<T>>;
+
+/// Id of an Amba device.
+#[derive(Clone, Copy)]
+pub struct DeviceId {
+ /// Device id.
+ pub id: u32,
+
+ /// Mask that identifies which bits are valid in the device id.
+ pub mask: u32,
+}
+
+// SAFETY: `ZERO` is all zeroed-out and `to_rawid` stores `offset` in `amba_id::data`.
+unsafe impl const driver::RawDeviceId for DeviceId {
+ type RawType = bindings::amba_id;
+ const ZERO: Self::RawType = bindings::amba_id {
+ id: 0,
+ mask: 0,
+ data: core::ptr::null_mut(),
+ };
+
+ fn to_rawid(&self, offset: isize) -> Self::RawType {
+ bindings::amba_id {
+ id: self.id,
+ mask: self.mask,
+ data: offset as _,
+ }
+ }
+}
+
+/// An amba driver.
+pub trait Driver {
+ /// Data stored on device by driver.
+ type Data: PointerWrapper + Send + Sync + driver::DeviceRemoval = ();
+
+ /// The type that implements the power-management operations.
+ ///
+ /// The default is a type that implements no power-management operations. Drivers that do
+ /// implement them need to specify the type (commonly [`Self`]).
+ type PowerOps: power::Operations<Data = Self::Data> = power::NoOperations<Self::Data>;
+
+ /// The type holding information about each device id supported by the driver.
+ type IdInfo: 'static = ();
+
+ /// The table of device ids supported by the driver.
+ const ID_TABLE: Option<driver::IdTable<'static, DeviceId, Self::IdInfo>> = None;
+
+ /// Probes for the device with the given id.
+ fn probe(dev: &mut Device, id_info: Option<&Self::IdInfo>) -> Result<Self::Data>;
+
+ /// Cleans any resources up that are associated with the device.
+ ///
+ /// This is called when the driver is detached from the device.
+ fn remove(_data: &Self::Data) {}
+}
+
+/// An adapter for the registration of Amba drivers.
+pub struct Adapter<T: Driver>(T);
+
+impl<T: Driver> driver::DriverOps for Adapter<T> {
+ type RegType = bindings::amba_driver;
+
+ unsafe fn register(
+ reg: *mut bindings::amba_driver,
+ name: &'static CStr,
+ module: &'static ThisModule,
+ ) -> Result {
+ // SAFETY: By the safety requirements of this function (defined in the trait definition),
+ // `reg` is non-null and valid.
+ let amba = unsafe { &mut *reg };
+ amba.drv.name = name.as_char_ptr();
+ amba.drv.owner = module.0;
+ amba.probe = Some(probe_callback::<T>);
+ amba.remove = Some(remove_callback::<T>);
+ if let Some(t) = T::ID_TABLE {
+ amba.id_table = t.as_ref();
+ }
+ if cfg!(CONFIG_PM) {
+ // SAFETY: `probe_callback` sets the driver data after calling `T::Data::into_pointer`,
+ // and we guarantee that `T::Data` is the same as `T::PowerOps::Data` by a constraint
+ // in the type declaration.
+ amba.drv.pm = unsafe { power::OpsTable::<T::PowerOps>::build() };
+ }
+ // SAFETY: By the safety requirements of this function, `reg` is valid and fully
+ // initialised.
+ to_result(unsafe { bindings::amba_driver_register(reg) })
+ }
+
+ unsafe fn unregister(reg: *mut bindings::amba_driver) {
+ // SAFETY: By the safety requirements of this function (defined in the trait definition),
+ // `reg` was passed (and updated) by a previous successful call to `amba_driver_register`.
+ unsafe { bindings::amba_driver_unregister(reg) };
+ }
+}
+
+unsafe extern "C" fn probe_callback<T: Driver>(
+ adev: *mut bindings::amba_device,
+ aid: *const bindings::amba_id,
+) -> core::ffi::c_int {
+ from_kernel_result! {
+ // SAFETY: `adev` is valid by the contract with the C code. `dev` is alive only for the
+ // duration of this call, so it is guaranteed to remain alive for the lifetime of `dev`.
+ let mut dev = unsafe { Device::from_ptr(adev) };
+ // SAFETY: `aid` is valid by the requirements the contract with the C code.
+ let offset = unsafe { (*aid).data };
+ let info = if offset.is_null() {
+ None
+ } else {
+ // SAFETY: The offset comes from a previous call to `offset_from` in `IdArray::new`,
+ // which guarantees that the resulting pointer is within the table.
+ let ptr = unsafe {
+ aid.cast::<u8>()
+ .offset(offset as _)
+ .cast::<Option<T::IdInfo>>()
+ };
+ // SAFETY: The id table has a static lifetime, so `ptr` is guaranteed to be valid for
+ // read.
+ unsafe { (&*ptr).as_ref() }
+ };
+ let data = T::probe(&mut dev, info)?;
+ let ptr = T::Data::into_pointer(data);
+ // SAFETY: `adev` is valid for write by the contract with the C code.
+ unsafe { bindings::amba_set_drvdata(adev, ptr as _) };
+ Ok(0)
+ }
+}
+
+unsafe extern "C" fn remove_callback<T: Driver>(adev: *mut bindings::amba_device) {
+ // SAFETY: `adev` is valid by the contract with the C code.
+ let ptr = unsafe { bindings::amba_get_drvdata(adev) };
+ // SAFETY: The value returned by `amba_get_drvdata` was stored by a previous call to
+ // `amba_set_drvdata` in `probe_callback` above; the value comes from a call to
+ // `T::Data::into_pointer`.
+ let data = unsafe { T::Data::from_pointer(ptr) };
+ T::remove(&data);
+ <T::Data as driver::DeviceRemoval>::device_remove(&data);
+}
+
+/// An Amba device.
+///
+/// # Invariants
+///
+/// The field `ptr` is non-null and valid for the lifetime of the object.
+pub struct Device {
+ ptr: *mut bindings::amba_device,
+ res: Option<Resource>,
+}
+
+impl Device {
+ /// Creates a new device from the given pointer.
+ ///
+ /// # Safety
+ ///
+ /// `ptr` must be non-null and valid. It must remain valid for the lifetime of the returned
+ /// instance.
+ unsafe fn from_ptr(ptr: *mut bindings::amba_device) -> Self {
+ // SAFETY: The safety requirements of the function ensure that `ptr` is valid.
+ let dev = unsafe { &mut *ptr };
+ // INVARIANT: The safety requirements of the function ensure the lifetime invariant.
+ Self {
+ ptr,
+ res: Resource::new(dev.res.start, dev.res.end),
+ }
+ }
+
+ /// Returns the io mem resource associated with the device, if there is one.
+ ///
+ /// Ownership of the resource is transferred to the caller, so subsequent calls to this
+ /// function will return [`None`].
+ pub fn take_resource(&mut self) -> Option<Resource> {
+ self.res.take()
+ }
+
+ /// Returns the index-th irq associated with the device, if one exists.
+ pub fn irq(&self, index: usize) -> Option<u32> {
+ // SAFETY: By the type invariants, `self.ptr` is valid for read.
+ let dev = unsafe { &*self.ptr };
+ if index >= dev.irq.len() || dev.irq[index] == 0 {
+ None
+ } else {
+ Some(dev.irq[index])
+ }
+ }
+}
+
+// SAFETY: The device returned by `raw_device` is the raw Amba device.
+unsafe impl device::RawDevice for Device {
+ fn raw_device(&self) -> *mut bindings::device {
+ // SAFETY: By the type invariants, we know that `self.ptr` is non-null and valid.
+ unsafe { &mut (*self.ptr).dev }
+ }
+}
+
+/// Declares a kernel module that exposes a single amba driver.
+///
+/// # Examples
+///
+/// ```ignore
+/// # use kernel::{amba, define_amba_id_table, module_amba_driver};
+/// #
+/// struct MyDriver;
+/// impl amba::Driver for MyDriver {
+/// // [...]
+/// # fn probe(_dev: &mut amba::Device, _id: Option<&Self::IdInfo>) -> Result {
+/// # Ok(())
+/// # }
+/// # define_amba_id_table! {(), [
+/// # ({ id: 0x00041061, mask: 0x000fffff }, None),
+/// # ]}
+/// }
+///
+/// module_amba_driver! {
+/// type: MyDriver,
+/// name: b"module_name",
+/// author: b"Author name",
+/// license: b"GPL",
+/// }
+/// ```
+#[macro_export]
+macro_rules! module_amba_driver {
+ ($($f:tt)*) => {
+ $crate::module_driver!(<T>, $crate::amba::Adapter<T>, { $($f)* });
+ };
+}
+
+/// Defines the id table for amba devices.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::{amba, define_amba_id_table};
+/// #
+/// # struct Sample;
+/// # impl kernel::amba::Driver for Sample {
+/// # fn probe(_dev: &mut amba::Device, _id: Option<&Self::IdInfo>) -> Result {
+/// # Ok(())
+/// # }
+/// define_amba_id_table! {(), [
+/// ({ id: 0x00041061, mask: 0x000fffff }, None),
+/// ]}
+/// # }
+/// ```
+#[macro_export]
+macro_rules! define_amba_id_table {
+ ($data_type:ty, $($t:tt)*) => {
+ type IdInfo = $data_type;
+ $crate::define_id_table!(ID_TABLE, $crate::amba::DeviceId, $data_type, $($t)*);
+ };
+}
diff --git a/rust/kernel/build_assert.rs b/rust/kernel/build_assert.rs
new file mode 100644
index 000000000000..72c533d8058d
--- /dev/null
+++ b/rust/kernel/build_assert.rs
@@ -0,0 +1,83 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Build-time assert.
+
+/// Fails the build if the code path calling `build_error!` can possibly be executed.
+///
+/// If the macro is executed in const context, `build_error!` will panic.
+/// If the compiler or optimizer cannot guarantee that `build_error!` can never
+/// be called, a build error will be triggered.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::build_error;
+/// #[inline]
+/// fn foo(a: usize) -> usize {
+/// a.checked_add(1).unwrap_or_else(|| build_error!("overflow"))
+/// }
+///
+/// assert_eq!(foo(usize::MAX - 1), usize::MAX); // OK.
+/// // foo(usize::MAX); // Fails to compile.
+/// ```
+#[macro_export]
+macro_rules! build_error {
+ () => {{
+ $crate::build_error("")
+ }};
+ ($msg:expr) => {{
+ $crate::build_error($msg)
+ }};
+}
+
+/// Asserts that a boolean expression is `true` at compile time.
+///
+/// If the condition is evaluated to `false` in const context, `build_assert!`
+/// will panic. If the compiler or optimizer cannot guarantee the condition will
+/// be evaluated to `true`, a build error will be triggered.
+///
+/// [`static_assert!`] should be preferred to `build_assert!` whenever possible.
+///
+/// # Examples
+///
+/// These examples show that different types of [`assert!`] will trigger errors
+/// at different stage of compilation. It is preferred to err as early as
+/// possible, so [`static_assert!`] should be used whenever possible.
+// TODO: Could be `compile_fail` when supported.
+/// ```ignore
+/// fn foo() {
+/// static_assert!(1 > 1); // Compile-time error
+/// build_assert!(1 > 1); // Build-time error
+/// assert!(1 > 1); // Run-time error
+/// }
+/// ```
+///
+/// When the condition refers to generic parameters or parameters of an inline function,
+/// [`static_assert!`] cannot be used. Use `build_assert!` in this scenario.
+/// ```
+/// fn foo<const N: usize>() {
+/// // `static_assert!(N > 1);` is not allowed
+/// build_assert!(N > 1); // Build-time check
+/// assert!(N > 1); // Run-time check
+/// }
+///
+/// #[inline]
+/// fn bar(n: usize) {
+/// // `static_assert!(n > 1);` is not allowed
+/// build_assert!(n > 1); // Build-time check
+/// assert!(n > 1); // Run-time check
+/// }
+/// ```
+#[macro_export]
+macro_rules! build_assert {
+ ($cond:expr $(,)?) => {{
+ if !$cond {
+ $crate::build_error(concat!("assertion failed: ", stringify!($cond)));
+ }
+ }};
+ ($cond:expr, $msg:expr) => {{
+ if !$cond {
+ $crate::build_error($msg);
+ }
+ }};
+}
diff --git a/rust/kernel/chrdev.rs b/rust/kernel/chrdev.rs
new file mode 100644
index 000000000000..5b1e083c23b9
--- /dev/null
+++ b/rust/kernel/chrdev.rs
@@ -0,0 +1,206 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Character devices.
+//!
+//! Also called "char devices", `chrdev`, `cdev`.
+//!
+//! C header: [`include/linux/cdev.h`](../../../../include/linux/cdev.h)
+//!
+//! Reference: <https://www.kernel.org/doc/html/latest/core-api/kernel-api.html#char-devices>
+
+use alloc::boxed::Box;
+use core::convert::TryInto;
+use core::marker::PhantomPinned;
+use core::pin::Pin;
+
+use crate::bindings;
+use crate::error::{code::*, Error, Result};
+use crate::file;
+use crate::str::CStr;
+
+/// Character device.
+///
+/// # Invariants
+///
+/// - [`self.0`] is valid and non-null.
+/// - [`(*self.0).ops`] is valid, non-null and has static lifetime.
+/// - [`(*self.0).owner`] is valid and, if non-null, has module lifetime.
+struct Cdev(*mut bindings::cdev);
+
+impl Cdev {
+ fn alloc(
+ fops: &'static bindings::file_operations,
+ module: &'static crate::ThisModule,
+ ) -> Result<Self> {
+ // SAFETY: FFI call.
+ let cdev = unsafe { bindings::cdev_alloc() };
+ if cdev.is_null() {
+ return Err(ENOMEM);
+ }
+ // SAFETY: `cdev` is valid and non-null since `cdev_alloc()`
+ // returned a valid pointer which was null-checked.
+ unsafe {
+ (*cdev).ops = fops;
+ (*cdev).owner = module.0;
+ }
+ // INVARIANTS:
+ // - [`self.0`] is valid and non-null.
+ // - [`(*self.0).ops`] is valid, non-null and has static lifetime,
+ // because it was coerced from a reference with static lifetime.
+ // - [`(*self.0).owner`] is valid and, if non-null, has module lifetime,
+ // guaranteed by the [`ThisModule`] invariant.
+ Ok(Self(cdev))
+ }
+
+ fn add(&mut self, dev: bindings::dev_t, count: core::ffi::c_uint) -> Result {
+ // SAFETY: According to the type invariants:
+ // - [`self.0`] can be safely passed to [`bindings::cdev_add`].
+ // - [`(*self.0).ops`] will live at least as long as [`self.0`].
+ // - [`(*self.0).owner`] will live at least as long as the
+ // module, which is an implicit requirement.
+ let rc = unsafe { bindings::cdev_add(self.0, dev, count) };
+ if rc != 0 {
+ return Err(Error::from_kernel_errno(rc));
+ }
+ Ok(())
+ }
+}
+
+impl Drop for Cdev {
+ fn drop(&mut self) {
+ // SAFETY: [`self.0`] is valid and non-null by the type invariants.
+ unsafe {
+ bindings::cdev_del(self.0);
+ }
+ }
+}
+
+struct RegistrationInner<const N: usize> {
+ dev: bindings::dev_t,
+ used: usize,
+ cdevs: [Option<Cdev>; N],
+ _pin: PhantomPinned,
+}
+
+/// Character device registration.
+///
+/// May contain up to a fixed number (`N`) of devices. Must be pinned.
+pub struct Registration<const N: usize> {
+ name: &'static CStr,
+ minors_start: u16,
+ this_module: &'static crate::ThisModule,
+ inner: Option<RegistrationInner<N>>,
+}
+
+impl<const N: usize> Registration<{ N }> {
+ /// Creates a [`Registration`] object for a character device.
+ ///
+ /// This does *not* register the device: see [`Self::register()`].
+ ///
+ /// This associated function is intended to be used when you need to avoid
+ /// a memory allocation, e.g. when the [`Registration`] is a member of
+ /// a bigger structure inside your [`crate::Module`] instance. If you
+ /// are going to pin the registration right away, call
+ /// [`Self::new_pinned()`] instead.
+ pub fn new(
+ name: &'static CStr,
+ minors_start: u16,
+ this_module: &'static crate::ThisModule,
+ ) -> Self {
+ Registration {
+ name,
+ minors_start,
+ this_module,
+ inner: None,
+ }
+ }
+
+ /// Creates a pinned [`Registration`] object for a character device.
+ ///
+ /// This does *not* register the device: see [`Self::register()`].
+ pub fn new_pinned(
+ name: &'static CStr,
+ minors_start: u16,
+ this_module: &'static crate::ThisModule,
+ ) -> Result<Pin<Box<Self>>> {
+ Ok(Pin::from(Box::try_new(Self::new(
+ name,
+ minors_start,
+ this_module,
+ ))?))
+ }
+
+ /// Registers a character device.
+ ///
+ /// You may call this once per device type, up to `N` times.
+ pub fn register<T: file::Operations<OpenData = ()>>(self: Pin<&mut Self>) -> Result {
+ // SAFETY: We must ensure that we never move out of `this`.
+ let this = unsafe { self.get_unchecked_mut() };
+ if this.inner.is_none() {
+ let mut dev: bindings::dev_t = 0;
+ // SAFETY: Calling unsafe function. `this.name` has `'static`
+ // lifetime.
+ let res = unsafe {
+ bindings::alloc_chrdev_region(
+ &mut dev,
+ this.minors_start.into(),
+ N.try_into()?,
+ this.name.as_char_ptr(),
+ )
+ };
+ if res != 0 {
+ return Err(Error::from_kernel_errno(res));
+ }
+ const NONE: Option<Cdev> = None;
+ this.inner = Some(RegistrationInner {
+ dev,
+ used: 0,
+ cdevs: [NONE; N],
+ _pin: PhantomPinned,
+ });
+ }
+
+ let mut inner = this.inner.as_mut().unwrap();
+ if inner.used == N {
+ return Err(EINVAL);
+ }
+
+ // SAFETY: The adapter doesn't retrieve any state yet, so it's compatible with any
+ // registration.
+ let fops = unsafe { file::OperationsVtable::<Self, T>::build() };
+ let mut cdev = Cdev::alloc(fops, this.this_module)?;
+ cdev.add(inner.dev + inner.used as bindings::dev_t, 1)?;
+ inner.cdevs[inner.used].replace(cdev);
+ inner.used += 1;
+ Ok(())
+ }
+}
+
+impl<const N: usize> file::OpenAdapter<()> for Registration<{ N }> {
+ unsafe fn convert(_inode: *mut bindings::inode, _file: *mut bindings::file) -> *const () {
+ // TODO: Update the SAFETY comment on the call to `FileOperationsVTable::build` above once
+ // this is updated to retrieve state.
+ &()
+ }
+}
+
+// SAFETY: `Registration` does not expose any of its state across threads
+// (it is fine for multiple threads to have a shared reference to it).
+unsafe impl<const N: usize> Sync for Registration<{ N }> {}
+
+impl<const N: usize> Drop for Registration<{ N }> {
+ fn drop(&mut self) {
+ if let Some(inner) = self.inner.as_mut() {
+ // Replicate kernel C behaviour: drop [`Cdev`]s before calling
+ // [`bindings::unregister_chrdev_region`].
+ for i in 0..inner.used {
+ inner.cdevs[i].take();
+ }
+ // SAFETY: [`self.inner`] is Some, so [`inner.dev`] was previously
+ // created using [`bindings::alloc_chrdev_region`].
+ unsafe {
+ bindings::unregister_chrdev_region(inner.dev, N.try_into().unwrap());
+ }
+ }
+ }
+}
diff --git a/rust/kernel/clk.rs b/rust/kernel/clk.rs
new file mode 100644
index 000000000000..1ec478d96abc
--- /dev/null
+++ b/rust/kernel/clk.rs
@@ -0,0 +1,79 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Common clock framework.
+//!
+//! C header: [`include/linux/clk.h`](../../../../include/linux/clk.h)
+
+use crate::{bindings, error::Result, to_result};
+use core::mem::ManuallyDrop;
+
+/// Represents `struct clk *`.
+///
+/// # Invariants
+///
+/// The pointer is valid.
+pub struct Clk(*mut bindings::clk);
+
+impl Clk {
+ /// Creates new clock structure from a raw pointer.
+ ///
+ /// # Safety
+ ///
+ /// The pointer must be valid.
+ pub unsafe fn new(clk: *mut bindings::clk) -> Self {
+ Self(clk)
+ }
+
+ /// Returns value of the rate field of `struct clk`.
+ pub fn get_rate(&self) -> usize {
+ // SAFETY: The pointer is valid by the type invariant.
+ unsafe { bindings::clk_get_rate(self.0) as usize }
+ }
+
+ /// Prepares and enables the underlying hardware clock.
+ ///
+ /// This function should not be called in atomic context.
+ pub fn prepare_enable(self) -> Result<EnabledClk> {
+ // SAFETY: The pointer is valid by the type invariant.
+ to_result(unsafe { bindings::clk_prepare_enable(self.0) })?;
+ Ok(EnabledClk(self))
+ }
+}
+
+impl Drop for Clk {
+ fn drop(&mut self) {
+ // SAFETY: The pointer is valid by the type invariant.
+ unsafe { bindings::clk_put(self.0) };
+ }
+}
+
+// SAFETY: `Clk` is not restricted to a single thread so it is safe
+// to move it between threads.
+unsafe impl Send for Clk {}
+
+/// A clock variant that is prepared and enabled.
+pub struct EnabledClk(Clk);
+
+impl EnabledClk {
+ /// Returns value of the rate field of `struct clk`.
+ pub fn get_rate(&self) -> usize {
+ self.0.get_rate()
+ }
+
+ /// Disables and later unprepares the underlying hardware clock prematurely.
+ ///
+ /// This function should not be called in atomic context.
+ pub fn disable_unprepare(self) -> Clk {
+ let mut clk = ManuallyDrop::new(self);
+ // SAFETY: The pointer is valid by the type invariant.
+ unsafe { bindings::clk_disable_unprepare(clk.0 .0) };
+ core::mem::replace(&mut clk.0, Clk(core::ptr::null_mut()))
+ }
+}
+
+impl Drop for EnabledClk {
+ fn drop(&mut self) {
+ // SAFETY: The pointer is valid by the type invariant.
+ unsafe { bindings::clk_disable_unprepare(self.0 .0) };
+ }
+}
diff --git a/rust/kernel/cred.rs b/rust/kernel/cred.rs
new file mode 100644
index 000000000000..beacc71d92ac
--- /dev/null
+++ b/rust/kernel/cred.rs
@@ -0,0 +1,46 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Credentials management.
+//!
+//! C header: [`include/linux/cred.h`](../../../../include/linux/cred.h)
+//!
+//! Reference: <https://www.kernel.org/doc/html/latest/security/credentials.html>
+
+use crate::{bindings, AlwaysRefCounted};
+use core::cell::UnsafeCell;
+
+/// Wraps the kernel's `struct cred`.
+///
+/// # Invariants
+///
+/// Instances of this type are always ref-counted, that is, a call to `get_cred` ensures that the
+/// allocation remains valid at least until the matching call to `put_cred`.
+#[repr(transparent)]
+pub struct Credential(pub(crate) UnsafeCell<bindings::cred>);
+
+impl Credential {
+ /// Creates a reference to a [`Credential`] from a valid pointer.
+ ///
+ /// # Safety
+ ///
+ /// The caller must ensure that `ptr` is valid and remains valid for the lifetime of the
+ /// returned [`Credential`] reference.
+ pub(crate) unsafe fn from_ptr<'a>(ptr: *const bindings::cred) -> &'a Self {
+ // SAFETY: The safety requirements guarantee the validity of the dereference, while the
+ // `Credential` type being transparent makes the cast ok.
+ unsafe { &*ptr.cast() }
+ }
+}
+
+// SAFETY: The type invariants guarantee that `Credential` is always ref-counted.
+unsafe impl AlwaysRefCounted for Credential {
+ fn inc_ref(&self) {
+ // SAFETY: The existence of a shared reference means that the refcount is nonzero.
+ unsafe { bindings::get_cred(self.0.get()) };
+ }
+
+ unsafe fn dec_ref(obj: core::ptr::NonNull<Self>) {
+ // SAFETY: The safety requirements guarantee that the refcount is nonzero.
+ unsafe { bindings::put_cred(obj.cast().as_ptr()) };
+ }
+}
diff --git a/rust/kernel/delay.rs b/rust/kernel/delay.rs
new file mode 100644
index 000000000000..1e987fa65941
--- /dev/null
+++ b/rust/kernel/delay.rs
@@ -0,0 +1,104 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Delay functions for operations like sleeping.
+//!
+//! C header: [`include/linux/delay.h`](../../../../include/linux/delay.h)
+
+use crate::bindings;
+use core::{cmp::min, time::Duration};
+
+const MILLIS_PER_SEC: u64 = 1_000;
+
+fn coarse_sleep_conversion(duration: Duration) -> core::ffi::c_uint {
+ let milli_as_nanos = Duration::MILLISECOND.subsec_nanos();
+
+ // Rounds the nanosecond component of `duration` up to the nearest millisecond.
+ let nanos_as_millis = duration.subsec_nanos().wrapping_add(milli_as_nanos - 1) / milli_as_nanos;
+
+ // Saturates the second component of `duration` to `c_uint::MAX`.
+ let seconds_as_millis = min(
+ duration.as_secs().saturating_mul(MILLIS_PER_SEC),
+ u64::from(core::ffi::c_uint::MAX),
+ ) as core::ffi::c_uint;
+
+ seconds_as_millis.saturating_add(nanos_as_millis)
+}
+
+/// Sleeps safely even with waitqueue interruptions.
+///
+/// This function forwards the call to the C side `msleep` function. As a result,
+/// `duration` will be rounded up to the nearest millisecond if granularity less
+/// than a millisecond is provided. Any [`Duration`] that exceeds
+/// [`c_uint::MAX`][core::ffi::c_uint::MAX] in milliseconds is saturated.
+///
+/// # Examples
+///
+// Keep these in sync with `test_coarse_sleep_examples`.
+/// ```
+/// # use core::time::Duration;
+/// # use kernel::delay::coarse_sleep;
+/// coarse_sleep(Duration::ZERO); // Equivalent to `msleep(0)`.
+/// coarse_sleep(Duration::from_nanos(1)); // Equivalent to `msleep(1)`.
+///
+/// coarse_sleep(Duration::from_nanos(1_000_000)); // Equivalent to `msleep(1)`.
+/// coarse_sleep(Duration::from_nanos(1_000_001)); // Equivalent to `msleep(2)`.
+/// coarse_sleep(Duration::from_nanos(1_999_999)); // Equivalent to `msleep(2)`.
+///
+/// coarse_sleep(Duration::from_millis(1)); // Equivalent to `msleep(1)`.
+/// coarse_sleep(Duration::from_millis(2)); // Equivalent to `msleep(2)`.
+///
+/// coarse_sleep(Duration::from_secs(1)); // Equivalent to `msleep(1000)`.
+/// coarse_sleep(Duration::new(1, 1)); // Equivalent to `msleep(1001)`.
+/// coarse_sleep(Duration::new(1, 2)); // Equivalent to `msleep(1001)`.
+/// ```
+pub fn coarse_sleep(duration: Duration) {
+ // SAFETY: `msleep` is safe for all values of its argument.
+ unsafe { bindings::msleep(coarse_sleep_conversion(duration)) }
+}
+
+#[cfg(test)]
+mod tests {
+ use super::{coarse_sleep_conversion, MILLIS_PER_SEC};
+ use core::time::Duration;
+
+ #[test]
+ fn test_coarse_sleep_examples() {
+ // Keep these in sync with `coarse_sleep`'s `# Examples` section.
+
+ assert_eq!(coarse_sleep_conversion(Duration::ZERO), 0);
+ assert_eq!(coarse_sleep_conversion(Duration::from_nanos(1)), 1);
+
+ assert_eq!(coarse_sleep_conversion(Duration::from_nanos(1_000_000)), 1);
+ assert_eq!(coarse_sleep_conversion(Duration::from_nanos(1_000_001)), 2);
+ assert_eq!(coarse_sleep_conversion(Duration::from_nanos(1_999_999)), 2);
+
+ assert_eq!(coarse_sleep_conversion(Duration::from_millis(1)), 1);
+ assert_eq!(coarse_sleep_conversion(Duration::from_millis(2)), 2);
+
+ assert_eq!(coarse_sleep_conversion(Duration::from_secs(1)), 1000);
+ assert_eq!(coarse_sleep_conversion(Duration::new(1, 1)), 1001);
+ assert_eq!(coarse_sleep_conversion(Duration::new(1, 2)), 1001);
+ }
+
+ #[test]
+ fn test_coarse_sleep_saturation() {
+ assert!(
+ coarse_sleep_conversion(Duration::new(
+ core::ffi::c_uint::MAX as u64 / MILLIS_PER_SEC,
+ 0
+ )) < core::ffi::c_uint::MAX
+ );
+ assert_eq!(
+ coarse_sleep_conversion(Duration::new(
+ core::ffi::c_uint::MAX as u64 / MILLIS_PER_SEC,
+ 999_999_999
+ )),
+ core::ffi::c_uint::MAX
+ );
+
+ assert_eq!(
+ coarse_sleep_conversion(Duration::MAX),
+ core::ffi::c_uint::MAX
+ );
+ }
+}
diff --git a/rust/kernel/device.rs b/rust/kernel/device.rs
new file mode 100644
index 000000000000..c37f555c534d
--- /dev/null
+++ b/rust/kernel/device.rs
@@ -0,0 +1,527 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Generic devices that are part of the kernel's driver model.
+//!
+//! C header: [`include/linux/device.h`](../../../../include/linux/device.h)
+
+#[cfg(CONFIG_COMMON_CLK)]
+use crate::{clk::Clk, error::from_kernel_err_ptr};
+
+use crate::{
+ bindings,
+ revocable::{Revocable, RevocableGuard},
+ str::CStr,
+ sync::{LockClassKey, NeedsLockClass, RevocableMutex, RevocableMutexGuard, UniqueRef},
+ Result,
+};
+use core::{
+ fmt,
+ ops::{Deref, DerefMut},
+ pin::Pin,
+};
+
+#[cfg(CONFIG_PRINTK)]
+use crate::c_str;
+
+/// A raw device.
+///
+/// # Safety
+///
+/// Implementers must ensure that the `*mut device` returned by [`RawDevice::raw_device`] is
+/// related to `self`, that is, actions on it will affect `self`. For example, if one calls
+/// `get_device`, then the refcount on the device represented by `self` will be incremented.
+///
+/// Additionally, implementers must ensure that the device is never renamed. Commit a5462516aa99
+/// ("driver-core: document restrictions on device_rename()") has details on why `device_rename`
+/// should not be used.
+pub unsafe trait RawDevice {
+ /// Returns the raw `struct device` related to `self`.
+ fn raw_device(&self) -> *mut bindings::device;
+
+ /// Returns the name of the device.
+ fn name(&self) -> &CStr {
+ let ptr = self.raw_device();
+
+ // SAFETY: `ptr` is valid because `self` keeps it alive.
+ let name = unsafe { bindings::dev_name(ptr) };
+
+ // SAFETY: The name of the device remains valid while it is alive (because the device is
+ // never renamed, per the safety requirement of this trait). This is guaranteed to be the
+ // case because the reference to `self` outlives the one of the returned `CStr` (enforced
+ // by the compiler because of their lifetimes).
+ unsafe { CStr::from_char_ptr(name) }
+ }
+
+ /// Lookups a clock producer consumed by this device.
+ ///
+ /// Returns a managed reference to the clock producer.
+ #[cfg(CONFIG_COMMON_CLK)]
+ fn clk_get(&self, id: Option<&CStr>) -> Result<Clk> {
+ let id_ptr = match id {
+ Some(cstr) => cstr.as_char_ptr(),
+ None => core::ptr::null(),
+ };
+
+ // SAFETY: `id_ptr` is optional and may be either a valid pointer
+ // from the type invariant or NULL otherwise.
+ let clk_ptr = unsafe { from_kernel_err_ptr(bindings::clk_get(self.raw_device(), id_ptr)) }?;
+
+ // SAFETY: Clock is initialized with valid pointer returned from `bindings::clk_get` call.
+ unsafe { Ok(Clk::new(clk_ptr)) }
+ }
+
+ /// Prints an emergency-level message (level 0) prefixed with device information.
+ ///
+ /// More details are available from [`dev_emerg`].
+ fn pr_emerg(&self, args: fmt::Arguments<'_>) {
+ // SAFETY: `klevel` is null-terminated, uses one of the kernel constants.
+ unsafe { self.printk(bindings::KERN_EMERG, args) };
+ }
+
+ /// Prints an alert-level message (level 1) prefixed with device information.
+ ///
+ /// More details are available from [`dev_alert`].
+ fn pr_alert(&self, args: fmt::Arguments<'_>) {
+ // SAFETY: `klevel` is null-terminated, uses one of the kernel constants.
+ unsafe { self.printk(bindings::KERN_ALERT, args) };
+ }
+
+ /// Prints a critical-level message (level 2) prefixed with device information.
+ ///
+ /// More details are available from [`dev_crit`].
+ fn pr_crit(&self, args: fmt::Arguments<'_>) {
+ // SAFETY: `klevel` is null-terminated, uses one of the kernel constants.
+ unsafe { self.printk(bindings::KERN_CRIT, args) };
+ }
+
+ /// Prints an error-level message (level 3) prefixed with device information.
+ ///
+ /// More details are available from [`dev_err`].
+ fn pr_err(&self, args: fmt::Arguments<'_>) {
+ // SAFETY: `klevel` is null-terminated, uses one of the kernel constants.
+ unsafe { self.printk(bindings::KERN_ERR, args) };
+ }
+
+ /// Prints a warning-level message (level 4) prefixed with device information.
+ ///
+ /// More details are available from [`dev_warn`].
+ fn pr_warn(&self, args: fmt::Arguments<'_>) {
+ // SAFETY: `klevel` is null-terminated, uses one of the kernel constants.
+ unsafe { self.printk(bindings::KERN_WARNING, args) };
+ }
+
+ /// Prints a notice-level message (level 5) prefixed with device information.
+ ///
+ /// More details are available from [`dev_notice`].
+ fn pr_notice(&self, args: fmt::Arguments<'_>) {
+ // SAFETY: `klevel` is null-terminated, uses one of the kernel constants.
+ unsafe { self.printk(bindings::KERN_NOTICE, args) };
+ }
+
+ /// Prints an info-level message (level 6) prefixed with device information.
+ ///
+ /// More details are available from [`dev_info`].
+ fn pr_info(&self, args: fmt::Arguments<'_>) {
+ // SAFETY: `klevel` is null-terminated, uses one of the kernel constants.
+ unsafe { self.printk(bindings::KERN_INFO, args) };
+ }
+
+ /// Prints a debug-level message (level 7) prefixed with device information.
+ ///
+ /// More details are available from [`dev_dbg`].
+ fn pr_dbg(&self, args: fmt::Arguments<'_>) {
+ if cfg!(debug_assertions) {
+ // SAFETY: `klevel` is null-terminated, uses one of the kernel constants.
+ unsafe { self.printk(bindings::KERN_DEBUG, args) };
+ }
+ }
+
+ /// Prints the provided message to the console.
+ ///
+ /// # Safety
+ ///
+ /// Callers must ensure that `klevel` is null-terminated; in particular, one of the
+ /// `KERN_*`constants, for example, `KERN_CRIT`, `KERN_ALERT`, etc.
+ #[cfg_attr(not(CONFIG_PRINTK), allow(unused_variables))]
+ unsafe fn printk(&self, klevel: &[u8], msg: fmt::Arguments<'_>) {
+ // SAFETY: `klevel` is null-terminated and one of the kernel constants. `self.raw_device`
+ // is valid because `self` is valid. The "%pA" format string expects a pointer to
+ // `fmt::Arguments`, which is what we're passing as the last argument.
+ #[cfg(CONFIG_PRINTK)]
+ unsafe {
+ bindings::_dev_printk(
+ klevel as *const _ as *const core::ffi::c_char,
+ self.raw_device(),
+ c_str!("%pA").as_char_ptr(),
+ &msg as *const _ as *const core::ffi::c_void,
+ )
+ };
+ }
+}
+
+/// A ref-counted device.
+///
+/// # Invariants
+///
+/// `ptr` is valid, non-null, and has a non-zero reference count. One of the references is owned by
+/// `self`, and will be decremented when `self` is dropped.
+pub struct Device {
+ pub(crate) ptr: *mut bindings::device,
+}
+
+// SAFETY: `Device` only holds a pointer to a C device, which is safe to be used from any thread.
+unsafe impl Send for Device {}
+
+// SAFETY: `Device` only holds a pointer to a C device, references to which are safe to be used
+// from any thread.
+unsafe impl Sync for Device {}
+
+impl Device {
+ /// Creates a new device instance.
+ ///
+ /// # Safety
+ ///
+ /// Callers must ensure that `ptr` is valid, non-null, and has a non-zero reference count.
+ pub unsafe fn new(ptr: *mut bindings::device) -> Self {
+ // SAFETY: By the safety requirements, ptr is valid and its refcounted will be incremented.
+ unsafe { bindings::get_device(ptr) };
+ // INVARIANT: The safety requirements satisfy all but one invariant, which is that `self`
+ // owns a reference. This is satisfied by the call to `get_device` above.
+ Self { ptr }
+ }
+
+ /// Creates a new device instance from an existing [`RawDevice`] instance.
+ pub fn from_dev(dev: &dyn RawDevice) -> Self {
+ // SAFETY: The requirements are satisfied by the existence of `RawDevice` and its safety
+ // requirements.
+ unsafe { Self::new(dev.raw_device()) }
+ }
+}
+
+// SAFETY: The device returned by `raw_device` is the one for which we hold a reference.
+unsafe impl RawDevice for Device {
+ fn raw_device(&self) -> *mut bindings::device {
+ self.ptr
+ }
+}
+
+impl Drop for Device {
+ fn drop(&mut self) {
+ // SAFETY: By the type invariants, we know that `self` owns a reference, so it is safe to
+ // relinquish it now.
+ unsafe { bindings::put_device(self.ptr) };
+ }
+}
+
+/// Device data.
+///
+/// When a device is removed (for whatever reason, for example, because the device was unplugged or
+/// because the user decided to unbind the driver), the driver is given a chance to clean its state
+/// up, and all io resources should ideally not be used anymore.
+///
+/// However, the device data is reference-counted because other subsystems hold pointers to it. So
+/// some device state must be freed and not used anymore, while others must remain accessible.
+///
+/// This struct separates the device data into three categories:
+/// 1. Registrations: are destroyed when the device is removed, but before the io resources
+/// become inaccessible.
+/// 2. Io resources: are available until the device is removed.
+/// 3. General data: remain available as long as the ref count is nonzero.
+///
+/// This struct implements the `DeviceRemoval` trait so that it can clean resources up even if not
+/// explicitly called by the device drivers.
+pub struct Data<T, U, V> {
+ registrations: RevocableMutex<T>,
+ resources: Revocable,
+ general: V,
+}
+
+/// Safely creates an new reference-counted instance of [`Data`].
+#[doc(hidden)]
+#[macro_export]
+macro_rules! new_device_data {
+ ($reg:expr, $res:expr, $gen:expr, $name:literal) => {{
+ static CLASS1: $crate::sync::LockClassKey = $crate::sync::LockClassKey::new();
+ static CLASS2: $crate::sync::LockClassKey = $crate::sync::LockClassKey::new();
+ let regs = $reg;
+ let res = $res;
+ let gen = $gen;
+ let name = $crate::c_str!($name);
+ $crate::device::Data::try_new(regs, res, gen, name, &CLASS1, &CLASS2)
+ }};
+}
+
+impl<T, U, V> Data<T, U, V> {
+ /// Creates a new instance of `Data`.
+ ///
+ /// It is recommended that the [`new_device_data`] macro be used as it automatically creates
+ /// the lock classes.
+ pub fn try_new(
+ registrations: T,
+ resources: U,
+ general: V,
+ name: &'static CStr,
+ key1: &'static LockClassKey,
+ key2: &'static LockClassKey,
+ ) -> Result<Pin<UniqueRef<Self>>> {
+ let mut ret = Pin::from(UniqueRef::try_new(Self {
+ // SAFETY: We call `RevocableMutex::init` below.
+ registrations: unsafe { RevocableMutex::new(registrations) },
+ resources: Revocable::new(resources),
+ general,
+ })?);
+
+ // SAFETY: `Data::registrations` is pinned when `Data` is.
+ let pinned = unsafe { ret.as_mut().map_unchecked_mut(|d| &mut d.registrations) };
+ pinned.init(name, key1, key2);
+ Ok(ret)
+ }
+
+ /// Returns the resources if they're still available.
+ pub fn resources(&self) -> Option<RevocableGuard<'_, U>> {
+ self.resources.try_access()
+ }
+
+ /// Returns the locked registrations if they're still available.
+ pub fn registrations(&self) -> Option<RevocableMutexGuard<'_, T>> {
+ self.registrations.try_write()
+ }
+}
+
+impl<T, U, V> crate::driver::DeviceRemoval for Data<T, U, V> {
+ fn device_remove(&self) {
+ // We revoke the registrations first so that resources are still available to them during
+ // unregistration.
+ self.registrations.revoke();
+
+ // Release resources now. General data remains available.
+ self.resources.revoke();
+ }
+}
+
+impl<T, U, V> Deref for Data<T, U, V> {
+ type Target = V;
+
+ fn deref(&self) -> &V {
+ &self.general
+ }
+}
+
+impl<T, U, V> DerefMut for Data<T, U, V> {
+ fn deref_mut(&mut self) -> &mut V {
+ &mut self.general
+ }
+}
+
+#[doc(hidden)]
+#[macro_export]
+macro_rules! dev_printk {
+ ($method:ident, $dev:expr, $($f:tt)*) => {
+ {
+ // We have an explicity `use` statement here so that callers of this macro are not
+ // required to explicitly use the `RawDevice` trait to use its functions.
+ use $crate::device::RawDevice;
+ ($dev).$method(core::format_args!($($f)*));
+ }
+ }
+}
+
+/// Prints an emergency-level message (level 0) prefixed with device information.
+///
+/// This level should be used if the system is unusable.
+///
+/// Equivalent to the kernel's `dev_emerg` macro.
+///
+/// Mimics the interface of [`std::print!`]. More information about the syntax is available from
+/// [`core::fmt`] and [`alloc::format!`].
+///
+/// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::device::Device;
+///
+/// fn example(dev: &Device) {
+/// dev_emerg!(dev, "hello {}\n", "there");
+/// }
+/// ```
+#[macro_export]
+macro_rules! dev_emerg {
+ ($($f:tt)*) => { $crate::dev_printk!(pr_emerg, $($f)*); }
+}
+
+/// Prints an alert-level message (level 1) prefixed with device information.
+///
+/// This level should be used if action must be taken immediately.
+///
+/// Equivalent to the kernel's `dev_alert` macro.
+///
+/// Mimics the interface of [`std::print!`]. More information about the syntax is available from
+/// [`core::fmt`] and [`alloc::format!`].
+///
+/// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::device::Device;
+///
+/// fn example(dev: &Device) {
+/// dev_alert!(dev, "hello {}\n", "there");
+/// }
+/// ```
+#[macro_export]
+macro_rules! dev_alert {
+ ($($f:tt)*) => { $crate::dev_printk!(pr_alert, $($f)*); }
+}
+
+/// Prints a critical-level message (level 2) prefixed with device information.
+///
+/// This level should be used in critical conditions.
+///
+/// Equivalent to the kernel's `dev_crit` macro.
+///
+/// Mimics the interface of [`std::print!`]. More information about the syntax is available from
+/// [`core::fmt`] and [`alloc::format!`].
+///
+/// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::device::Device;
+///
+/// fn example(dev: &Device) {
+/// dev_crit!(dev, "hello {}\n", "there");
+/// }
+/// ```
+#[macro_export]
+macro_rules! dev_crit {
+ ($($f:tt)*) => { $crate::dev_printk!(pr_crit, $($f)*); }
+}
+
+/// Prints an error-level message (level 3) prefixed with device information.
+///
+/// This level should be used in error conditions.
+///
+/// Equivalent to the kernel's `dev_err` macro.
+///
+/// Mimics the interface of [`std::print!`]. More information about the syntax is available from
+/// [`core::fmt`] and [`alloc::format!`].
+///
+/// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::device::Device;
+///
+/// fn example(dev: &Device) {
+/// dev_err!(dev, "hello {}\n", "there");
+/// }
+/// ```
+#[macro_export]
+macro_rules! dev_err {
+ ($($f:tt)*) => { $crate::dev_printk!(pr_err, $($f)*); }
+}
+
+/// Prints a warning-level message (level 4) prefixed with device information.
+///
+/// This level should be used in warning conditions.
+///
+/// Equivalent to the kernel's `dev_warn` macro.
+///
+/// Mimics the interface of [`std::print!`]. More information about the syntax is available from
+/// [`core::fmt`] and [`alloc::format!`].
+///
+/// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::device::Device;
+///
+/// fn example(dev: &Device) {
+/// dev_warn!(dev, "hello {}\n", "there");
+/// }
+/// ```
+#[macro_export]
+macro_rules! dev_warn {
+ ($($f:tt)*) => { $crate::dev_printk!(pr_warn, $($f)*); }
+}
+
+/// Prints a notice-level message (level 5) prefixed with device information.
+///
+/// This level should be used in normal but significant conditions.
+///
+/// Equivalent to the kernel's `dev_notice` macro.
+///
+/// Mimics the interface of [`std::print!`]. More information about the syntax is available from
+/// [`core::fmt`] and [`alloc::format!`].
+///
+/// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::device::Device;
+///
+/// fn example(dev: &Device) {
+/// dev_notice!(dev, "hello {}\n", "there");
+/// }
+/// ```
+#[macro_export]
+macro_rules! dev_notice {
+ ($($f:tt)*) => { $crate::dev_printk!(pr_notice, $($f)*); }
+}
+
+/// Prints an info-level message (level 6) prefixed with device information.
+///
+/// This level should be used for informational messages.
+///
+/// Equivalent to the kernel's `dev_info` macro.
+///
+/// Mimics the interface of [`std::print!`]. More information about the syntax is available from
+/// [`core::fmt`] and [`alloc::format!`].
+///
+/// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::device::Device;
+///
+/// fn example(dev: &Device) {
+/// dev_info!(dev, "hello {}\n", "there");
+/// }
+/// ```
+#[macro_export]
+macro_rules! dev_info {
+ ($($f:tt)*) => { $crate::dev_printk!(pr_info, $($f)*); }
+}
+
+/// Prints a debug-level message (level 7) prefixed with device information.
+///
+/// This level should be used for debug messages.
+///
+/// Equivalent to the kernel's `dev_dbg` macro, except that it doesn't support dynamic debug yet.
+///
+/// Mimics the interface of [`std::print!`]. More information about the syntax is available from
+/// [`core::fmt`] and [`alloc::format!`].
+///
+/// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::device::Device;
+///
+/// fn example(dev: &Device) {
+/// dev_dbg!(dev, "hello {}\n", "there");
+/// }
+/// ```
+#[macro_export]
+macro_rules! dev_dbg {
+ ($($f:tt)*) => { $crate::dev_printk!(pr_dbg, $($f)*); }
+}
diff --git a/rust/kernel/driver.rs b/rust/kernel/driver.rs
new file mode 100644
index 000000000000..82b39231e311
--- /dev/null
+++ b/rust/kernel/driver.rs
@@ -0,0 +1,442 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Generic support for drivers of different buses (e.g., PCI, Platform, Amba, etc.).
+//!
+//! Each bus/subsystem is expected to implement [`DriverOps`], which allows drivers to register
+//! using the [`Registration`] class.
+
+use crate::{error::code::*, str::CStr, sync::Ref, Result, ThisModule};
+use alloc::boxed::Box;
+use core::{cell::UnsafeCell, marker::PhantomData, ops::Deref, pin::Pin};
+
+/// A subsystem (e.g., PCI, Platform, Amba, etc.) that allows drivers to be written for it.
+pub trait DriverOps {
+ /// The type that holds information about the registration. This is typically a struct defined
+ /// by the C portion of the kernel.
+ type RegType: Default;
+
+ /// Registers a driver.
+ ///
+ /// # Safety
+ ///
+ /// `reg` must point to valid, initialised, and writable memory. It may be modified by this
+ /// function to hold registration state.
+ ///
+ /// On success, `reg` must remain pinned and valid until the matching call to
+ /// [`DriverOps::unregister`].
+ unsafe fn register(
+ reg: *mut Self::RegType,
+ name: &'static CStr,
+ module: &'static ThisModule,
+ ) -> Result;
+
+ /// Unregisters a driver previously registered with [`DriverOps::register`].
+ ///
+ /// # Safety
+ ///
+ /// `reg` must point to valid writable memory, initialised by a previous successful call to
+ /// [`DriverOps::register`].
+ unsafe fn unregister(reg: *mut Self::RegType);
+}
+
+/// The registration of a driver.
+pub struct Registration<T: DriverOps> {
+ is_registered: bool,
+ concrete_reg: UnsafeCell<T::RegType>,
+}
+
+// SAFETY: `Registration` has no fields or methods accessible via `&Registration`, so it is safe to
+// share references to it with multiple threads as nothing can be done.
+unsafe impl<T: DriverOps> Sync for Registration<T> {}
+
+impl<T: DriverOps> Registration<T> {
+ /// Creates a new instance of the registration object.
+ pub fn new() -> Self {
+ Self {
+ is_registered: false,
+ concrete_reg: UnsafeCell::new(T::RegType::default()),
+ }
+ }
+
+ /// Allocates a pinned registration object and registers it.
+ ///
+ /// Returns a pinned heap-allocated representation of the registration.
+ pub fn new_pinned(name: &'static CStr, module: &'static ThisModule) -> Result<Pin<Box<Self>>> {
+ let mut reg = Pin::from(Box::try_new(Self::new())?);
+ reg.as_mut().register(name, module)?;
+ Ok(reg)
+ }
+
+ /// Registers a driver with its subsystem.
+ ///
+ /// It must be pinned because the memory block that represents the registration is potentially
+ /// self-referential.
+ pub fn register(
+ self: Pin<&mut Self>,
+ name: &'static CStr,
+ module: &'static ThisModule,
+ ) -> Result {
+ // SAFETY: We never move out of `this`.
+ let this = unsafe { self.get_unchecked_mut() };
+ if this.is_registered {
+ // Already registered.
+ return Err(EINVAL);
+ }
+
+ // SAFETY: `concrete_reg` was initialised via its default constructor. It is only freed
+ // after `Self::drop` is called, which first calls `T::unregister`.
+ unsafe { T::register(this.concrete_reg.get(), name, module) }?;
+
+ this.is_registered = true;
+ Ok(())
+ }
+}
+
+impl<T: DriverOps> Default for Registration<T> {
+ fn default() -> Self {
+ Self::new()
+ }
+}
+
+impl<T: DriverOps> Drop for Registration<T> {
+ fn drop(&mut self) {
+ if self.is_registered {
+ // SAFETY: This path only runs if a previous call to `T::register` completed
+ // successfully.
+ unsafe { T::unregister(self.concrete_reg.get()) };
+ }
+ }
+}
+
+/// Conversion from a device id to a raw device id.
+///
+/// This is meant to be implemented by buses/subsystems so that they can use [`IdTable`] to
+/// guarantee (at compile-time) zero-termination of device id tables provided by drivers.
+///
+/// # Safety
+///
+/// Implementers must ensure that:
+/// - [`RawDeviceId::ZERO`] is actually a zeroed-out version of the raw device id.
+/// - [`RawDeviceId::to_rawid`] stores `offset` in the context/data field of the raw device id so
+/// that buses can recover the pointer to the data.
+pub unsafe trait RawDeviceId {
+ /// The raw type that holds the device id.
+ ///
+ /// Id tables created from [`Self`] are going to hold this type in its zero-terminated array.
+ type RawType: Copy;
+
+ /// A zeroed-out representation of the raw device id.
+ ///
+ /// Id tables created from [`Self`] use [`Self::ZERO`] as the sentinel to indicate the end of
+ /// the table.
+ const ZERO: Self::RawType;
+
+ /// Converts an id into a raw id.
+ ///
+ /// `offset` is the offset from the memory location where the raw device id is stored to the
+ /// location where its associated context information is stored. Implementations must store
+ /// this in the appropriate context/data field of the raw type.
+ fn to_rawid(&self, offset: isize) -> Self::RawType;
+}
+
+/// A zero-terminated device id array, followed by context data.
+#[repr(C)]
+pub struct IdArray<T: RawDeviceId, U, const N: usize> {
+ ids: [T::RawType; N],
+ sentinel: T::RawType,
+ id_infos: [Option; N],
+}
+
+impl<T: RawDeviceId, U, const N: usize> IdArray<T, U, N> {
+ /// Creates a new instance of the array.
+ ///
+ /// The contents are derived from the given identifiers and context information.
+ pub const fn new(ids: [T; N], infos: [Option; N]) -> Self
+ where
+ T: ~const RawDeviceId + Copy,
+ {
+ let mut array = Self {
+ ids: [T::ZERO; N],
+ sentinel: T::ZERO,
+ id_infos: infos,
+ };
+ let mut i = 0usize;
+ while i < N {
+ // SAFETY: Both pointers are within `array` (or one byte beyond), consequently they are
+ // derived from the same allocated object. We are using a `u8` pointer, whose size 1,
+ // so the pointers are necessarily 1-byte aligned.
+ let offset = unsafe {
+ (&array.id_infos[i] as *const _ as *const u8)
+ .offset_from(&array.ids[i] as *const _ as _)
+ };
+ array.ids[i] = ids[i].to_rawid(offset);
+ i += 1;
+ }
+ array
+ }
+
+ /// Returns an `IdTable` backed by `self`.
+ ///
+ /// This is used to essentially erase the array size.
+ pub const fn as_table(&self) -> IdTable<'_, T, U> {
+ IdTable {
+ first: &self.ids[0],
+ _p: PhantomData,
+ }
+ }
+}
+
+/// A device id table.
+///
+/// The table is guaranteed to be zero-terminated and to be followed by an array of context data of
+/// type `Option`.
+pub struct IdTable<'a, T: RawDeviceId, U> {
+ first: &'a T::RawType,
+ _p: PhantomData<&'a U>,
+}
+
+impl<T: RawDeviceId, U> const AsRef<T::RawType> for IdTable<'_, T, U> {
+ fn as_ref(&self) -> &T::RawType {
+ self.first
+ }
+}
+
+/// Counts the number of parenthesis-delimited, comma-separated items.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::count_paren_items;
+///
+/// assert_eq!(0, count_paren_items!());
+/// assert_eq!(1, count_paren_items!((A)));
+/// assert_eq!(1, count_paren_items!((A),));
+/// assert_eq!(2, count_paren_items!((A), (B)));
+/// assert_eq!(2, count_paren_items!((A), (B),));
+/// assert_eq!(3, count_paren_items!((A), (B), (C)));
+/// assert_eq!(3, count_paren_items!((A), (B), (C),));
+/// ```
+#[macro_export]
+macro_rules! count_paren_items {
+ (($($item:tt)*), $($remaining:tt)*) => { 1 + $crate::count_paren_items!($($remaining)*) };
+ (($($item:tt)*)) => { 1 };
+ () => { 0 };
+}
+
+/// Converts a comma-separated list of pairs into an array with the first element. That is, it
+/// discards the second element of the pair.
+///
+/// Additionally, it automatically introduces a type if the first element is warpped in curly
+/// braces, for example, if it's `{v: 10}`, it becomes `X { v: 10 }`; this is to avoid repeating
+/// the type.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::first_item;
+///
+/// #[derive(PartialEq, Debug)]
+/// struct X {
+/// v: u32,
+/// }
+///
+/// assert_eq!([] as [X; 0], first_item!(X, ));
+/// assert_eq!([X { v: 10 }], first_item!(X, ({ v: 10 }, Y)));
+/// assert_eq!([X { v: 10 }], first_item!(X, ({ v: 10 }, Y),));
+/// assert_eq!([X { v: 10 }], first_item!(X, (X { v: 10 }, Y)));
+/// assert_eq!([X { v: 10 }], first_item!(X, (X { v: 10 }, Y),));
+/// assert_eq!([X { v: 10 }, X { v: 20 }], first_item!(X, ({ v: 10 }, Y), ({ v: 20 }, Y)));
+/// assert_eq!([X { v: 10 }, X { v: 20 }], first_item!(X, ({ v: 10 }, Y), ({ v: 20 }, Y),));
+/// assert_eq!([X { v: 10 }, X { v: 20 }], first_item!(X, (X { v: 10 }, Y), (X { v: 20 }, Y)));
+/// assert_eq!([X { v: 10 }, X { v: 20 }], first_item!(X, (X { v: 10 }, Y), (X { v: 20 }, Y),));
+/// assert_eq!([X { v: 10 }, X { v: 20 }, X { v: 30 }],
+/// first_item!(X, ({ v: 10 }, Y), ({ v: 20 }, Y), ({v: 30}, Y)));
+/// assert_eq!([X { v: 10 }, X { v: 20 }, X { v: 30 }],
+/// first_item!(X, ({ v: 10 }, Y), ({ v: 20 }, Y), ({v: 30}, Y),));
+/// assert_eq!([X { v: 10 }, X { v: 20 }, X { v: 30 }],
+/// first_item!(X, (X { v: 10 }, Y), (X { v: 20 }, Y), (X {v: 30}, Y)));
+/// assert_eq!([X { v: 10 }, X { v: 20 }, X { v: 30 }],
+/// first_item!(X, (X { v: 10 }, Y), (X { v: 20 }, Y), (X {v: 30}, Y),));
+/// ```
+#[macro_export]
+macro_rules! first_item {
+ ($id_type:ty, $(({$($first:tt)*}, $second:expr)),* $(,)?) => {
+ {
+ type IdType = $id_type;
+ [$(IdType{$($first)*},)*]
+ }
+ };
+ ($id_type:ty, $(($first:expr, $second:expr)),* $(,)?) => { [$($first,)*] };
+}
+
+/// Converts a comma-separated list of pairs into an array with the second element. That is, it
+/// discards the first element of the pair.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::second_item;
+///
+/// assert_eq!([] as [u32; 0], second_item!());
+/// assert_eq!([10u32], second_item!((X, 10u32)));
+/// assert_eq!([10u32], second_item!((X, 10u32),));
+/// assert_eq!([10u32], second_item!(({ X }, 10u32)));
+/// assert_eq!([10u32], second_item!(({ X }, 10u32),));
+/// assert_eq!([10u32, 20], second_item!((X, 10u32), (X, 20)));
+/// assert_eq!([10u32, 20], second_item!((X, 10u32), (X, 20),));
+/// assert_eq!([10u32, 20], second_item!(({ X }, 10u32), ({ X }, 20)));
+/// assert_eq!([10u32, 20], second_item!(({ X }, 10u32), ({ X }, 20),));
+/// assert_eq!([10u32, 20, 30], second_item!((X, 10u32), (X, 20), (X, 30)));
+/// assert_eq!([10u32, 20, 30], second_item!((X, 10u32), (X, 20), (X, 30),));
+/// assert_eq!([10u32, 20, 30], second_item!(({ X }, 10u32), ({ X }, 20), ({ X }, 30)));
+/// assert_eq!([10u32, 20, 30], second_item!(({ X }, 10u32), ({ X }, 20), ({ X }, 30),));
+/// ```
+#[macro_export]
+macro_rules! second_item {
+ ($(({$($first:tt)*}, $second:expr)),* $(,)?) => { [$($second,)*] };
+ ($(($first:expr, $second:expr)),* $(,)?) => { [$($second,)*] };
+}
+
+/// Defines a new constant [`IdArray`] with a concise syntax.
+///
+/// It is meant to be used by buses and subsystems to create a similar macro with their device id
+/// type already specified, i.e., with fewer parameters to the end user.
+///
+/// # Examples
+///
+// TODO: Exported but not usable by kernel modules (requires `const_trait_impl`).
+/// ```ignore
+/// #![feature(const_trait_impl)]
+/// # use kernel::{define_id_array, driver::RawDeviceId};
+///
+/// #[derive(Copy, Clone)]
+/// struct Id(u32);
+///
+/// // SAFETY: `ZERO` is all zeroes and `to_rawid` stores `offset` as the second element of the raw
+/// // device id pair.
+/// unsafe impl const RawDeviceId for Id {
+/// type RawType = (u64, isize);
+/// const ZERO: Self::RawType = (0, 0);
+/// fn to_rawid(&self, offset: isize) -> Self::RawType {
+/// (self.0 as u64 + 1, offset)
+/// }
+/// }
+///
+/// define_id_array!(A1, Id, (), []);
+/// define_id_array!(A2, Id, &'static [u8], [(Id(10), None)]);
+/// define_id_array!(A3, Id, &'static [u8], [(Id(10), Some(b"id1")), ]);
+/// define_id_array!(A4, Id, &'static [u8], [(Id(10), Some(b"id1")), (Id(20), Some(b"id2"))]);
+/// define_id_array!(A5, Id, &'static [u8], [(Id(10), Some(b"id1")), (Id(20), Some(b"id2")), ]);
+/// define_id_array!(A6, Id, &'static [u8], [(Id(10), None), (Id(20), Some(b"id2")), ]);
+/// define_id_array!(A7, Id, &'static [u8], [(Id(10), Some(b"id1")), (Id(20), None), ]);
+/// define_id_array!(A8, Id, &'static [u8], [(Id(10), None), (Id(20), None), ]);
+/// ```
+#[macro_export]
+macro_rules! define_id_array {
+ ($table_name:ident, $id_type:ty, $data_type:ty, [ $($t:tt)* ]) => {
+ const $table_name:
+ $crate::driver::IdArray<$id_type, $data_type, { $crate::count_paren_items!($($t)*) }> =
+ $crate::driver::IdArray::new(
+ $crate::first_item!($id_type, $($t)*), $crate::second_item!($($t)*));
+ };
+}
+
+/// Defines a new constant [`IdTable`] with a concise syntax.
+///
+/// It is meant to be used by buses and subsystems to create a similar macro with their device id
+/// type already specified, i.e., with fewer parameters to the end user.
+///
+/// # Examples
+///
+// TODO: Exported but not usable by kernel modules (requires `const_trait_impl`).
+/// ```ignore
+/// #![feature(const_trait_impl)]
+/// # use kernel::{define_id_table, driver::RawDeviceId};
+///
+/// #[derive(Copy, Clone)]
+/// struct Id(u32);
+///
+/// // SAFETY: `ZERO` is all zeroes and `to_rawid` stores `offset` as the second element of the raw
+/// // device id pair.
+/// unsafe impl const RawDeviceId for Id {
+/// type RawType = (u64, isize);
+/// const ZERO: Self::RawType = (0, 0);
+/// fn to_rawid(&self, offset: isize) -> Self::RawType {
+/// (self.0 as u64 + 1, offset)
+/// }
+/// }
+///
+/// define_id_table!(T1, Id, &'static [u8], [(Id(10), None)]);
+/// define_id_table!(T2, Id, &'static [u8], [(Id(10), Some(b"id1")), ]);
+/// define_id_table!(T3, Id, &'static [u8], [(Id(10), Some(b"id1")), (Id(20), Some(b"id2"))]);
+/// define_id_table!(T4, Id, &'static [u8], [(Id(10), Some(b"id1")), (Id(20), Some(b"id2")), ]);
+/// define_id_table!(T5, Id, &'static [u8], [(Id(10), None), (Id(20), Some(b"id2")), ]);
+/// define_id_table!(T6, Id, &'static [u8], [(Id(10), Some(b"id1")), (Id(20), None), ]);
+/// define_id_table!(T7, Id, &'static [u8], [(Id(10), None), (Id(20), None), ]);
+/// ```
+#[macro_export]
+macro_rules! define_id_table {
+ ($table_name:ident, $id_type:ty, $data_type:ty, [ $($t:tt)* ]) => {
+ const $table_name: Option<$crate::driver::IdTable<'static, $id_type, $data_type>> = {
+ $crate::define_id_array!(ARRAY, $id_type, $data_type, [ $($t)* ]);
+ Some(ARRAY.as_table())
+ };
+ };
+}
+
+/// Custom code within device removal.
+pub trait DeviceRemoval {
+ /// Cleans resources up when the device is removed.
+ ///
+ /// This is called when a device is removed and offers implementers the chance to run some code
+ /// that cleans state up.
+ fn device_remove(&self);
+}
+
+impl DeviceRemoval for () {
+ fn device_remove(&self) {}
+}
+
+impl<T: DeviceRemoval> DeviceRemoval for Ref<T> {
+ fn device_remove(&self) {
+ self.deref().device_remove();
+ }
+}
+
+impl<T: DeviceRemoval> DeviceRemoval for Box<T> {
+ fn device_remove(&self) {
+ self.deref().device_remove();
+ }
+}
+
+/// A kernel module that only registers the given driver on init.
+///
+/// This is a helper struct to make it easier to define single-functionality modules, in this case,
+/// modules that offer a single driver.
+pub struct Module<T: DriverOps> {
+ _driver: Pin<Box<Registration<T>>>,
+}
+
+impl<T: DriverOps> crate::Module for Module<T> {
+ fn init(name: &'static CStr, module: &'static ThisModule) -> Result<Self> {
+ Ok(Self {
+ _driver: Registration::new_pinned(name, module)?,
+ })
+ }
+}
+
+/// Declares a kernel module that exposes a single driver.
+///
+/// It is meant to be used as a helper by other subsystems so they can more easily expose their own
+/// macros.
+#[macro_export]
+macro_rules! module_driver {
+ (<$gen_type:ident>, $driver_ops:ty, { type: $type:ty, $($f:tt)* }) => {
+ type Ops<$gen_type> = $driver_ops;
+ type ModuleType = $crate::driver::Module<Ops<$type>>;
+ $crate::prelude::module! {
+ type: ModuleType,
+ $($f)*
+ }
+ }
+}
diff --git a/rust/kernel/error.rs b/rust/kernel/error.rs
new file mode 100644
index 000000000000..f968aa91ddf2
--- /dev/null
+++ b/rust/kernel/error.rs
@@ -0,0 +1,564 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Kernel errors.
+//!
+//! C header: [`include/uapi/asm-generic/errno-base.h`](../../../include/uapi/asm-generic/errno-base.h)
+
+use crate::bindings;
+use crate::str::CStr;
+use alloc::{
+ alloc::{AllocError, LayoutError},
+ collections::TryReserveError,
+};
+use core::convert::From;
+use core::fmt;
+use core::num::TryFromIntError;
+use core::str::{self, Utf8Error};
+
+/// Contains the C-compatible error codes.
+pub mod code {
+ macro_rules! declare_err {
+ ($err:tt $(,)? $($doc:expr),+) => {
+ $(
+ #[doc = $doc]
+ )*
+ pub const $err: super::Error = super::Error(-(crate::bindings::$err as i32));
+ };
+ }
+
+ declare_err!(EPERM, "Operation not permitted.");
+
+ declare_err!(ENOENT, "No such file or directory.");
+
+ declare_err!(ESRCH, "No such process.");
+
+ declare_err!(EINTR, "Interrupted system call.");
+
+ declare_err!(EIO, "I/O error.");
+
+ declare_err!(ENXIO, "No such device or address.");
+
+ declare_err!(E2BIG, "Argument list too long.");
+
+ declare_err!(ENOEXEC, "Exec format error.");
+
+ declare_err!(EBADF, "Bad file number.");
+
+ declare_err!(ECHILD, "Exec format error.");
+
+ declare_err!(EAGAIN, "Try again.");
+
+ declare_err!(ENOMEM, "Out of memory.");
+
+ declare_err!(EACCES, "Permission denied.");
+
+ declare_err!(EFAULT, "Bad address.");
+
+ declare_err!(ENOTBLK, "Block device required.");
+
+ declare_err!(EBUSY, "Device or resource busy.");
+
+ declare_err!(EEXIST, "File exists.");
+
+ declare_err!(EXDEV, "Cross-device link.");
+
+ declare_err!(ENODEV, "No such device.");
+
+ declare_err!(ENOTDIR, "Not a directory.");
+
+ declare_err!(EISDIR, "Is a directory.");
+
+ declare_err!(EINVAL, "Invalid argument.");
+
+ declare_err!(ENFILE, "File table overflow.");
+
+ declare_err!(EMFILE, "Too many open files.");
+
+ declare_err!(ENOTTY, "Not a typewriter.");
+
+ declare_err!(ETXTBSY, "Text file busy.");
+
+ declare_err!(EFBIG, "File too large.");
+
+ declare_err!(ENOSPC, "No space left on device.");
+
+ declare_err!(ESPIPE, "Illegal seek.");
+
+ declare_err!(EROFS, "Read-only file system.");
+
+ declare_err!(EMLINK, "Too many links.");
+
+ declare_err!(EPIPE, "Broken pipe.");
+
+ declare_err!(EDOM, "Math argument out of domain of func.");
+
+ declare_err!(ERANGE, "Math result not representable.");
+
+ declare_err!(EDEADLK, "Resource deadlock would occur");
+
+ declare_err!(ENAMETOOLONG, "File name too long");
+
+ declare_err!(ENOLCK, "No record locks available");
+
+ declare_err!(
+ ENOSYS,
+ "Invalid system call number.",
+ "",
+ "This error code is special: arch syscall entry code will return",
+ "[`ENOSYS`] if users try to call a syscall that doesn't exist.",
+ "To keep failures of syscalls that really do exist distinguishable from",
+ "failures due to attempts to use a nonexistent syscall, syscall",
+ "implementations should refrain from returning [`ENOSYS`]."
+ );
+
+ declare_err!(ENOTEMPTY, "Directory not empty.");
+
+ declare_err!(ELOOP, "Too many symbolic links encountered.");
+
+ declare_err!(EWOULDBLOCK, "Operation would block.");
+
+ declare_err!(ENOMSG, "No message of desired type.");
+
+ declare_err!(EIDRM, "Identifier removed.");
+
+ declare_err!(ECHRNG, "Channel number out of range.");
+
+ declare_err!(EL2NSYNC, "Level 2 not synchronized.");
+
+ declare_err!(EL3HLT, "Level 3 halted.");
+
+ declare_err!(EL3RST, "Level 3 reset.");
+
+ declare_err!(ELNRNG, "Link number out of range.");
+
+ declare_err!(EUNATCH, "Protocol driver not attached.");
+
+ declare_err!(ENOCSI, "No CSI structure available.");
+
+ declare_err!(EL2HLT, "Level 2 halted.");
+
+ declare_err!(EBADE, "Invalid exchange.");
+
+ declare_err!(EBADR, "Invalid request descriptor.");
+
+ declare_err!(EXFULL, "Exchange full.");
+
+ declare_err!(ENOANO, "No anode.");
+
+ declare_err!(EBADRQC, "Invalid request code.");
+
+ declare_err!(EBADSLT, "Invalid slot.");
+
+ declare_err!(EDEADLOCK, "Resource deadlock would occur.");
+
+ declare_err!(EBFONT, "Bad font file format.");
+
+ declare_err!(ENOSTR, "Device not a stream.");
+
+ declare_err!(ENODATA, "No data available.");
+
+ declare_err!(ETIME, "Timer expired.");
+
+ declare_err!(ENOSR, "Out of streams resources.");
+
+ declare_err!(ENONET, "Machine is not on the network.");
+
+ declare_err!(ENOPKG, "Package not installed.");
+
+ declare_err!(EREMOTE, "Object is remote.");
+
+ declare_err!(ENOLINK, "Link has been severed.");
+
+ declare_err!(EADV, "Advertise error.");
+
+ declare_err!(ESRMNT, "Srmount error.");
+
+ declare_err!(ECOMM, "Communication error on send.");
+
+ declare_err!(EPROTO, "Protocol error.");
+
+ declare_err!(EMULTIHOP, "Multihop attempted.");
+
+ declare_err!(EDOTDOT, "RFS specific error.");
+
+ declare_err!(EBADMSG, "Not a data message.");
+
+ declare_err!(EOVERFLOW, "Value too large for defined data type.");
+
+ declare_err!(ENOTUNIQ, "Name not unique on network.");
+
+ declare_err!(EBADFD, "File descriptor in bad state.");
+
+ declare_err!(EREMCHG, "Remote address changed.");
+
+ declare_err!(ELIBACC, "Can not access a needed shared library.");
+
+ declare_err!(ELIBBAD, "Accessing a corrupted shared library.");
+
+ declare_err!(ELIBSCN, ".lib section in a.out corrupted.");
+
+ declare_err!(ELIBMAX, "Attempting to link in too many shared libraries.");
+
+ declare_err!(ELIBEXEC, "Cannot exec a shared library directly.");
+
+ declare_err!(EILSEQ, "Illegal byte sequence.");
+
+ declare_err!(ERESTART, "Interrupted system call should be restarted.");
+
+ declare_err!(ESTRPIPE, "Streams pipe error.");
+
+ declare_err!(EUSERS, "Too many users.");
+
+ declare_err!(ENOTSOCK, "Socket operation on non-socket.");
+
+ declare_err!(EDESTADDRREQ, "Destination address required.");
+
+ declare_err!(EMSGSIZE, "Message too long.");
+
+ declare_err!(EPROTOTYPE, "Protocol wrong type for socket.");
+
+ declare_err!(ENOPROTOOPT, "Protocol not available.");
+
+ declare_err!(EPROTONOSUPPORT, "Protocol not supported.");
+
+ declare_err!(ESOCKTNOSUPPORT, "Socket type not supported.");
+
+ declare_err!(EOPNOTSUPP, "Operation not supported on transport endpoint.");
+
+ declare_err!(EPFNOSUPPORT, "Protocol family not supported.");
+
+ declare_err!(EAFNOSUPPORT, "Address family not supported by protocol.");
+
+ declare_err!(EADDRINUSE, "Address already in use.");
+
+ declare_err!(EADDRNOTAVAIL, "Cannot assign requested address.");
+
+ declare_err!(ENETDOWN, "Network is down.");
+
+ declare_err!(ENETUNREACH, "Network is unreachable.");
+
+ declare_err!(ENETRESET, "Network dropped connection because of reset.");
+
+ declare_err!(ECONNABORTED, "Software caused connection abort.");
+
+ declare_err!(ECONNRESET, "Connection reset by peer.");
+
+ declare_err!(ENOBUFS, "No buffer space available.");
+
+ declare_err!(EISCONN, "Transport endpoint is already connected.");
+
+ declare_err!(ENOTCONN, "Transport endpoint is not connected.");
+
+ declare_err!(ESHUTDOWN, "Cannot send after transport endpoint shutdown.");
+
+ declare_err!(ETOOMANYREFS, "Too many references: cannot splice.");
+
+ declare_err!(ETIMEDOUT, "Connection timed out.");
+
+ declare_err!(ECONNREFUSED, "Connection refused.");
+
+ declare_err!(EHOSTDOWN, "Host is down.");
+
+ declare_err!(EHOSTUNREACH, "No route to host.");
+
+ declare_err!(EALREADY, "Operation already in progress.");
+
+ declare_err!(EINPROGRESS, "Operation now in progress.");
+
+ declare_err!(ESTALE, "Stale file handle.");
+
+ declare_err!(EUCLEAN, "Structure needs cleaning.");
+
+ declare_err!(ENOTNAM, "Not a XENIX named type file.");
+
+ declare_err!(ENAVAIL, "No XENIX semaphores available.");
+
+ declare_err!(EISNAM, "Is a named type file.");
+
+ declare_err!(EREMOTEIO, "Remote I/O error.");
+
+ declare_err!(EDQUOT, "Quota exceeded.");
+
+ declare_err!(ENOMEDIUM, "No medium found.");
+
+ declare_err!(EMEDIUMTYPE, "Wrong medium type.");
+
+ declare_err!(ECANCELED, "Operation Canceled.");
+
+ declare_err!(ENOKEY, "Required key not available.");
+
+ declare_err!(EKEYEXPIRED, "Key has expired.");
+
+ declare_err!(EKEYREVOKED, "Key has been revoked.");
+
+ declare_err!(EKEYREJECTED, "Key was rejected by service.");
+
+ declare_err!(EOWNERDEAD, "Owner died.", "", "For robust mutexes.");
+
+ declare_err!(ENOTRECOVERABLE, "State not recoverable.");
+
+ declare_err!(ERFKILL, "Operation not possible due to RF-kill.");
+
+ declare_err!(EHWPOISON, "Memory page has hardware error.");
+
+ declare_err!(ERESTARTSYS, "Restart the system call.");
+
+ declare_err!(ENOTSUPP, "Operation is not supported.");
+
+ declare_err!(ENOPARAM, "Parameter not supported.");
+}
+
+/// Generic integer kernel error.
+///
+/// The kernel defines a set of integer generic error codes based on C and
+/// POSIX ones. These codes may have a more specific meaning in some contexts.
+///
+/// # Invariants
+///
+/// The value is a valid `errno` (i.e. `>= -MAX_ERRNO && < 0`).
+#[derive(Clone, Copy, PartialEq, Eq)]
+pub struct Error(core::ffi::c_int);
+
+impl Error {
+ /// Creates an [`Error`] from a kernel error code.
+ ///
+ /// It is a bug to pass an out-of-range `errno`. `EINVAL` would
+ /// be returned in such a case.
+ pub(crate) fn from_kernel_errno(errno: core::ffi::c_int) -> Error {
+ if errno < -(bindings::MAX_ERRNO as i32) || errno >= 0 {
+ // TODO: Make it a `WARN_ONCE` once available.
+ crate::pr_warn!(
+ "attempted to create `Error` with out of range `errno`: {}",
+ errno
+ );
+ return code::EINVAL;
+ }
+
+ // INVARIANT: The check above ensures the type invariant
+ // will hold.
+ Error(errno)
+ }
+
+ /// Creates an [`Error`] from a kernel error code.
+ ///
+ /// # Safety
+ ///
+ /// `errno` must be within error code range (i.e. `>= -MAX_ERRNO && < 0`).
+ pub(crate) unsafe fn from_kernel_errno_unchecked(errno: core::ffi::c_int) -> Error {
+ // INVARIANT: The contract ensures the type invariant
+ // will hold.
+ Error(errno)
+ }
+
+ /// Returns the kernel error code.
+ pub fn to_kernel_errno(self) -> core::ffi::c_int {
+ self.0
+ }
+
+ /// Returns a string representing the error, if one exists.
+ #[cfg(not(testlib))]
+ pub fn name(&self) -> Option<&'static CStr> {
+ // SAFETY: Just an FFI call, there are no extra safety requirements.
+ let ptr = unsafe { bindings::errname(-self.0) };
+ if ptr.is_null() {
+ None
+ } else {
+ // SAFETY: The string returned by `errname` is static and `NUL`-terminated.
+ Some(unsafe { CStr::from_char_ptr(ptr) })
+ }
+ }
+
+ /// Returns a string representing the error, if one exists.
+ ///
+ /// When `testlib` is configured, this always returns `None` to avoid the dependency on a
+ /// kernel function so that tests that use this (e.g., by calling [`Result::unwrap`]) can still
+ /// run in userspace.
+ #[cfg(testlib)]
+ pub fn name(&self) -> Option<&'static CStr> {
+ None
+ }
+}
+
+impl fmt::Debug for Error {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ match self.name() {
+ // Print out number if no name can be found.
+ None => f.debug_tuple("Error").field(&-self.0).finish(),
+ // SAFETY: These strings are ASCII-only.
+ Some(name) => f
+ .debug_tuple(unsafe { str::from_utf8_unchecked(name) })
+ .finish(),
+ }
+ }
+}
+
+impl From<TryFromIntError> for Error {
+ fn from(_: TryFromIntError) -> Error {
+ code::EINVAL
+ }
+}
+
+impl From<Utf8Error> for Error {
+ fn from(_: Utf8Error) -> Error {
+ code::EINVAL
+ }
+}
+
+impl From<TryReserveError> for Error {
+ fn from(_: TryReserveError) -> Error {
+ code::ENOMEM
+ }
+}
+
+impl From<LayoutError> for Error {
+ fn from(_: LayoutError) -> Error {
+ code::ENOMEM
+ }
+}
+
+impl From<core::fmt::Error> for Error {
+ fn from(_: core::fmt::Error) -> Error {
+ code::EINVAL
+ }
+}
+
+impl From<core::convert::Infallible> for Error {
+ fn from(e: core::convert::Infallible) -> Error {
+ match e {}
+ }
+}
+
+/// A [`Result`] with an [`Error`] error type.
+///
+/// To be used as the return type for functions that may fail.
+///
+/// # Error codes in C and Rust
+///
+/// In C, it is common that functions indicate success or failure through
+/// their return value; modifying or returning extra data through non-`const`
+/// pointer parameters. In particular, in the kernel, functions that may fail
+/// typically return an `int` that represents a generic error code. We model
+/// those as [`Error`].
+///
+/// In Rust, it is idiomatic to model functions that may fail as returning
+/// a [`Result`]. Since in the kernel many functions return an error code,
+/// [`Result`] is a type alias for a [`core::result::Result`] that uses
+/// [`Error`] as its error type.
+///
+/// Note that even if a function does not return anything when it succeeds,
+/// it should still be modeled as returning a `Result` rather than
+/// just an [`Error`].
+pub type Result<T = ()> = core::result::Result<T, Error>;
+
+impl From<AllocError> for Error {
+ fn from(_: AllocError) -> Error {
+ code::ENOMEM
+ }
+}
+
+// # Invariant: `-bindings::MAX_ERRNO` fits in an `i16`.
+crate::static_assert!(bindings::MAX_ERRNO <= -(i16::MIN as i32) as u32);
+
+pub(crate) fn from_kernel_result_helper<T>(r: Result<T>) -> T
+where
+ T: From<i16>,
+{
+ match r {
+ Ok(v) => v,
+ // NO-OVERFLOW: negative `errno`s are no smaller than `-bindings::MAX_ERRNO`,
+ // `-bindings::MAX_ERRNO` fits in an `i16` as per invariant above,
+ // therefore a negative `errno` always fits in an `i16` and will not overflow.
+ Err(e) => T::from(e.to_kernel_errno() as i16),
+ }
+}
+
+/// Transforms a [`crate::error::Result<T>`] to a kernel C integer result.
+///
+/// This is useful when calling Rust functions that return [`crate::error::Result<T>`]
+/// from inside `extern "C"` functions that need to return an integer
+/// error result.
+///
+/// `T` should be convertible to an `i16` via `From<i16>`.
+///
+/// # Examples
+///
+/// ```ignore
+/// # use kernel::from_kernel_result;
+/// # use kernel::bindings;
+/// unsafe extern "C" fn probe_callback(
+/// pdev: *mut bindings::platform_device,
+/// ) -> core::ffi::c_int {
+/// from_kernel_result! {
+/// let ptr = devm_alloc(pdev)?;
+/// bindings::platform_set_drvdata(pdev, ptr);
+/// Ok(0)
+/// }
+/// }
+/// ```
+macro_rules! from_kernel_result {
+ ($($tt:tt)*) => {{
+ $crate::error::from_kernel_result_helper((|| {
+ $($tt)*
+ })())
+ }};
+}
+
+pub(crate) use from_kernel_result;
+
+/// Transform a kernel "error pointer" to a normal pointer.
+///
+/// Some kernel C API functions return an "error pointer" which optionally
+/// embeds an `errno`. Callers are supposed to check the returned pointer
+/// for errors. This function performs the check and converts the "error pointer"
+/// to a normal pointer in an idiomatic fashion.
+///
+/// # Examples
+///
+/// ```ignore
+/// # use kernel::from_kernel_err_ptr;
+/// # use kernel::bindings;
+/// fn devm_platform_ioremap_resource(
+/// pdev: &mut PlatformDevice,
+/// index: u32,
+/// ) -> Result<*mut core::ffi::c_void> {
+/// // SAFETY: FFI call.
+/// unsafe {
+/// from_kernel_err_ptr(bindings::devm_platform_ioremap_resource(
+/// pdev.to_ptr(),
+/// index,
+/// ))
+/// }
+/// }
+/// ```
+// TODO: Remove `dead_code` marker once an in-kernel client is available.
+#[allow(dead_code)]
+pub(crate) fn from_kernel_err_ptr<T>(ptr: *mut T) -> Result<*mut T> {
+ // CAST: Casting a pointer to `*const core::ffi::c_void` is always valid.
+ let const_ptr: *const core::ffi::c_void = ptr.cast();
+ // SAFETY: The FFI function does not deref the pointer.
+ if unsafe { bindings::IS_ERR(const_ptr) } {
+ // SAFETY: The FFI function does not deref the pointer.
+ let err = unsafe { bindings::PTR_ERR(const_ptr) };
+ // CAST: If `IS_ERR()` returns `true`,
+ // then `PTR_ERR()` is guaranteed to return a
+ // negative value greater-or-equal to `-bindings::MAX_ERRNO`,
+ // which always fits in an `i16`, as per the invariant above.
+ // And an `i16` always fits in an `i32`. So casting `err` to
+ // an `i32` can never overflow, and is always valid.
+ //
+ // SAFETY: `IS_ERR()` ensures `err` is a
+ // negative value greater-or-equal to `-bindings::MAX_ERRNO`.
+ return Err(unsafe { Error::from_kernel_errno_unchecked(err as i32) });
+ }
+ Ok(ptr)
+}
+
+/// Converts an integer as returned by a C kernel function to an error if it's negative, and
+/// `Ok(())` otherwise.
+pub fn to_result(err: core::ffi::c_int) -> Result {
+ if err < 0 {
+ Err(Error::from_kernel_errno(err))
+ } else {
+ Ok(())
+ }
+}
diff --git a/rust/kernel/file.rs b/rust/kernel/file.rs
new file mode 100644
index 000000000000..62538e6b3eea
--- /dev/null
+++ b/rust/kernel/file.rs
@@ -0,0 +1,887 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Files and file descriptors.
+//!
+//! C headers: [`include/linux/fs.h`](../../../../include/linux/fs.h) and
+//! [`include/linux/file.h`](../../../../include/linux/file.h)
+
+use crate::{
+ bindings,
+ cred::Credential,
+ error::{code::*, from_kernel_result, Error, Result},
+ io_buffer::{IoBufferReader, IoBufferWriter},
+ iov_iter::IovIter,
+ mm,
+ sync::CondVar,
+ types::PointerWrapper,
+ user_ptr::{UserSlicePtr, UserSlicePtrReader, UserSlicePtrWriter},
+ ARef, AlwaysRefCounted,
+};
+use core::convert::{TryFrom, TryInto};
+use core::{cell::UnsafeCell, marker, mem, ptr};
+use macros::vtable;
+
+/// Flags associated with a [`File`].
+pub mod flags {
+ /// File is opened in append mode.
+ pub const O_APPEND: u32 = bindings::O_APPEND;
+
+ /// Signal-driven I/O is enabled.
+ pub const O_ASYNC: u32 = bindings::FASYNC;
+
+ /// Close-on-exec flag is set.
+ pub const O_CLOEXEC: u32 = bindings::O_CLOEXEC;
+
+ /// File was created if it didn't already exist.
+ pub const O_CREAT: u32 = bindings::O_CREAT;
+
+ /// Direct I/O is enabled for this file.
+ pub const O_DIRECT: u32 = bindings::O_DIRECT;
+
+ /// File must be a directory.
+ pub const O_DIRECTORY: u32 = bindings::O_DIRECTORY;
+
+ /// Like [`O_SYNC`] except metadata is not synced.
+ pub const O_DSYNC: u32 = bindings::O_DSYNC;
+
+ /// Ensure that this file is created with the `open(2)` call.
+ pub const O_EXCL: u32 = bindings::O_EXCL;
+
+ /// Large file size enabled (`off64_t` over `off_t`).
+ pub const O_LARGEFILE: u32 = bindings::O_LARGEFILE;
+
+ /// Do not update the file last access time.
+ pub const O_NOATIME: u32 = bindings::O_NOATIME;
+
+ /// File should not be used as process's controlling terminal.
+ pub const O_NOCTTY: u32 = bindings::O_NOCTTY;
+
+ /// If basename of path is a symbolic link, fail open.
+ pub const O_NOFOLLOW: u32 = bindings::O_NOFOLLOW;
+
+ /// File is using nonblocking I/O.
+ pub const O_NONBLOCK: u32 = bindings::O_NONBLOCK;
+
+ /// Also known as `O_NDELAY`.
+ ///
+ /// This is effectively the same flag as [`O_NONBLOCK`] on all architectures
+ /// except SPARC64.
+ pub const O_NDELAY: u32 = bindings::O_NDELAY;
+
+ /// Used to obtain a path file descriptor.
+ pub const O_PATH: u32 = bindings::O_PATH;
+
+ /// Write operations on this file will flush data and metadata.
+ pub const O_SYNC: u32 = bindings::O_SYNC;
+
+ /// This file is an unnamed temporary regular file.
+ pub const O_TMPFILE: u32 = bindings::O_TMPFILE;
+
+ /// File should be truncated to length 0.
+ pub const O_TRUNC: u32 = bindings::O_TRUNC;
+
+ /// Bitmask for access mode flags.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use kernel::file;
+ /// # fn do_something() {}
+ /// # let flags = 0;
+ /// if (flags & file::flags::O_ACCMODE) == file::flags::O_RDONLY {
+ /// do_something();
+ /// }
+ /// ```
+ pub const O_ACCMODE: u32 = bindings::O_ACCMODE;
+
+ /// File is read only.
+ pub const O_RDONLY: u32 = bindings::O_RDONLY;
+
+ /// File is write only.
+ pub const O_WRONLY: u32 = bindings::O_WRONLY;
+
+ /// File can be both read and written.
+ pub const O_RDWR: u32 = bindings::O_RDWR;
+}
+
+/// Wraps the kernel's `struct file`.
+///
+/// # Invariants
+///
+/// Instances of this type are always ref-counted, that is, a call to `get_file` ensures that the
+/// allocation remains valid at least until the matching call to `fput`.
+#[repr(transparent)]
+pub struct File(pub(crate) UnsafeCell<bindings::file>);
+
+// TODO: Accessing fields of `struct file` through the pointer is UB because other threads may be
+// writing to them. However, this is how the C code currently operates: naked reads and writes to
+// fields. Even if we used relaxed atomics on the Rust side, we can't force this on the C side.
+impl File {
+ /// Constructs a new [`struct file`] wrapper from a file descriptor.
+ ///
+ /// The file descriptor belongs to the current process.
+ pub fn from_fd(fd: u32) -> Result<ARef<Self>> {
+ // SAFETY: FFI call, there are no requirements on `fd`.
+ let ptr = ptr::NonNull::new(unsafe { bindings::fget(fd) }).ok_or(EBADF)?;
+
+ // SAFETY: `fget` increments the refcount before returning.
+ Ok(unsafe { ARef::from_raw(ptr.cast()) })
+ }
+
+ /// Creates a reference to a [`File`] from a valid pointer.
+ ///
+ /// # Safety
+ ///
+ /// The caller must ensure that `ptr` is valid and remains valid for the lifetime of the
+ /// returned [`File`] instance.
+ pub(crate) unsafe fn from_ptr<'a>(ptr: *const bindings::file) -> &'a File {
+ // SAFETY: The safety requirements guarantee the validity of the dereference, while the
+ // `File` type being transparent makes the cast ok.
+ unsafe { &*ptr.cast() }
+ }
+
+ /// Returns the current seek/cursor/pointer position (`struct file::f_pos`).
+ pub fn pos(&self) -> u64 {
+ // SAFETY: The file is valid because the shared reference guarantees a nonzero refcount.
+ unsafe { core::ptr::addr_of!((*self.0.get()).f_pos).read() as _ }
+ }
+
+ /// Returns the credentials of the task that originally opened the file.
+ pub fn cred(&self) -> &Credential {
+ // SAFETY: The file is valid because the shared reference guarantees a nonzero refcount.
+ let ptr = unsafe { core::ptr::addr_of!((*self.0.get()).f_cred).read() };
+ // SAFETY: The lifetimes of `self` and `Credential` are tied, so it is guaranteed that
+ // the credential pointer remains valid (because the file is still alive, and it doesn't
+ // change over the lifetime of a file).
+ unsafe { Credential::from_ptr(ptr) }
+ }
+
+ /// Returns the flags associated with the file.
+ ///
+ /// The flags are a combination of the constants in [`flags`].
+ pub fn flags(&self) -> u32 {
+ // SAFETY: The file is valid because the shared reference guarantees a nonzero refcount.
+ unsafe { core::ptr::addr_of!((*self.0.get()).f_flags).read() }
+ }
+}
+
+// SAFETY: The type invariants guarantee that `File` is always ref-counted.
+unsafe impl AlwaysRefCounted for File {
+ fn inc_ref(&self) {
+ // SAFETY: The existence of a shared reference means that the refcount is nonzero.
+ unsafe { bindings::get_file(self.0.get()) };
+ }
+
+ unsafe fn dec_ref(obj: ptr::NonNull<Self>) {
+ // SAFETY: The safety requirements guarantee that the refcount is nonzero.
+ unsafe { bindings::fput(obj.cast().as_ptr()) }
+ }
+}
+
+/// A file descriptor reservation.
+///
+/// This allows the creation of a file descriptor in two steps: first, we reserve a slot for it,
+/// then we commit or drop the reservation. The first step may fail (e.g., the current process ran
+/// out of available slots), but commit and drop never fail (and are mutually exclusive).
+pub struct FileDescriptorReservation {
+ fd: u32,
+}
+
+impl FileDescriptorReservation {
+ /// Creates a new file descriptor reservation.
+ pub fn new(flags: u32) -> Result<Self> {
+ // SAFETY: FFI call, there are no safety requirements on `flags`.
+ let fd = unsafe { bindings::get_unused_fd_flags(flags) };
+ if fd < 0 {
+ return Err(Error::from_kernel_errno(fd));
+ }
+ Ok(Self { fd: fd as _ })
+ }
+
+ /// Returns the file descriptor number that was reserved.
+ pub fn reserved_fd(&self) -> u32 {
+ self.fd
+ }
+
+ /// Commits the reservation.
+ ///
+ /// The previously reserved file descriptor is bound to `file`.
+ pub fn commit(self, file: ARef<File>) {
+ // SAFETY: `self.fd` was previously returned by `get_unused_fd_flags`, and `file.ptr` is
+ // guaranteed to have an owned ref count by its type invariants.
+ unsafe { bindings::fd_install(self.fd, file.0.get()) };
+
+ // `fd_install` consumes both the file descriptor and the file reference, so we cannot run
+ // the destructors.
+ core::mem::forget(self);
+ core::mem::forget(file);
+ }
+}
+
+impl Drop for FileDescriptorReservation {
+ fn drop(&mut self) {
+ // SAFETY: `self.fd` was returned by a previous call to `get_unused_fd_flags`.
+ unsafe { bindings::put_unused_fd(self.fd) };
+ }
+}
+
+/// Wraps the kernel's `struct poll_table_struct`.
+///
+/// # Invariants
+///
+/// The pointer `PollTable::ptr` is null or valid.
+pub struct PollTable {
+ ptr: *mut bindings::poll_table_struct,
+}
+
+impl PollTable {
+ /// Constructors a new `struct poll_table_struct` wrapper.
+ ///
+ /// # Safety
+ ///
+ /// The pointer `ptr` must be either null or a valid pointer for the lifetime of the object.
+ unsafe fn from_ptr(ptr: *mut bindings::poll_table_struct) -> Self {
+ Self { ptr }
+ }
+
+ /// Associates the given file and condition variable to this poll table. It means notifying the
+ /// condition variable will notify the poll table as well; additionally, the association
+ /// between the condition variable and the file will automatically be undone by the kernel when
+ /// the file is destructed. To unilaterally remove the association before then, one can call
+ /// [`CondVar::free_waiters`].
+ ///
+ /// # Safety
+ ///
+ /// If the condition variable is destroyed before the file, then [`CondVar::free_waiters`] must
+ /// be called to ensure that all waiters are flushed out.
+ pub unsafe fn register_wait<'a>(&self, file: &'a File, cv: &'a CondVar) {
+ if self.ptr.is_null() {
+ return;
+ }
+
+ // SAFETY: `PollTable::ptr` is guaranteed to be valid by the type invariants and the null
+ // check above.
+ let table = unsafe { &*self.ptr };
+ if let Some(proc) = table._qproc {
+ // SAFETY: All pointers are known to be valid.
+ unsafe { proc(file.0.get() as _, cv.wait_list.get(), self.ptr) }
+ }
+ }
+}
+
+/// Equivalent to [`std::io::SeekFrom`].
+///
+/// [`std::io::SeekFrom`]: https://doc.rust-lang.org/std/io/enum.SeekFrom.html
+pub enum SeekFrom {
+ /// Equivalent to C's `SEEK_SET`.
+ Start(u64),
+
+ /// Equivalent to C's `SEEK_END`.
+ End(i64),
+
+ /// Equivalent to C's `SEEK_CUR`.
+ Current(i64),
+}
+
+pub(crate) struct OperationsVtable<A, T>(marker::PhantomData<A>, marker::PhantomData<T>);
+
+impl<A: OpenAdapter<T::OpenData>, T: Operations> OperationsVtable<A, T> {
+ /// Called by the VFS when an inode should be opened.
+ ///
+ /// Calls `T::open` on the returned value of `A::convert`.
+ ///
+ /// # Safety
+ ///
+ /// The returned value of `A::convert` must be a valid non-null pointer and
+ /// `T:open` must return a valid non-null pointer on an `Ok` result.
+ unsafe extern "C" fn open_callback(
+ inode: *mut bindings::inode,
+ file: *mut bindings::file,
+ ) -> core::ffi::c_int {
+ from_kernel_result! {
+ // SAFETY: `A::convert` must return a valid non-null pointer that
+ // should point to data in the inode or file that lives longer
+ // than the following use of `T::open`.
+ let arg = unsafe { A::convert(inode, file) };
+ // SAFETY: The C contract guarantees that `file` is valid. Additionally,
+ // `fileref` never outlives this function, so it is guaranteed to be
+ // valid.
+ let fileref = unsafe { File::from_ptr(file) };
+ // SAFETY: `arg` was previously returned by `A::convert` and must
+ // be a valid non-null pointer.
+ let ptr = T::open(unsafe { &*arg }, fileref)?.into_pointer();
+ // SAFETY: The C contract guarantees that `private_data` is available
+ // for implementers of the file operations (no other C code accesses
+ // it), so we know that there are no concurrent threads/CPUs accessing
+ // it (it's not visible to any other Rust code).
+ unsafe { (*file).private_data = ptr as *mut core::ffi::c_void };
+ Ok(0)
+ }
+ }
+
+ unsafe extern "C" fn read_callback(
+ file: *mut bindings::file,
+ buf: *mut core::ffi::c_char,
+ len: core::ffi::c_size_t,
+ offset: *mut bindings::loff_t,
+ ) -> core::ffi::c_ssize_t {
+ from_kernel_result! {
+ let mut data =
+ unsafe { UserSlicePtr::new(buf as *mut core::ffi::c_void, len).writer() };
+ // SAFETY: `private_data` was initialised by `open_callback` with a value returned by
+ // `T::Data::into_pointer`. `T::Data::from_pointer` is only called by the
+ // `release` callback, which the C API guarantees that will be called only when all
+ // references to `file` have been released, so we know it can't be called while this
+ // function is running.
+ let f = unsafe { T::Data::borrow((*file).private_data) };
+ // No `FMODE_UNSIGNED_OFFSET` support, so `offset` must be in [0, 2^63).
+ // See <https://github.com/fishinabarrel/linux-kernel-module-rust/pull/113>.
+ let read = T::read(
+ f,
+ unsafe { File::from_ptr(file) },
+ &mut data,
+ unsafe { *offset }.try_into()?,
+ )?;
+ unsafe { (*offset) += bindings::loff_t::try_from(read).unwrap() };
+ Ok(read as _)
+ }
+ }
+
+ unsafe extern "C" fn read_iter_callback(
+ iocb: *mut bindings::kiocb,
+ raw_iter: *mut bindings::iov_iter,
+ ) -> isize {
+ from_kernel_result! {
+ let mut iter = unsafe { IovIter::from_ptr(raw_iter) };
+ let file = unsafe { (*iocb).ki_filp };
+ let offset = unsafe { (*iocb).ki_pos };
+ // SAFETY: `private_data` was initialised by `open_callback` with a value returned by
+ // `T::Data::into_pointer`. `T::Data::from_pointer` is only called by the
+ // `release` callback, which the C API guarantees that will be called only when all
+ // references to `file` have been released, so we know it can't be called while this
+ // function is running.
+ let f = unsafe { T::Data::borrow((*file).private_data) };
+ let read = T::read(
+ f,
+ unsafe { File::from_ptr(file) },
+ &mut iter,
+ offset.try_into()?,
+ )?;
+ unsafe { (*iocb).ki_pos += bindings::loff_t::try_from(read).unwrap() };
+ Ok(read as _)
+ }
+ }
+
+ unsafe extern "C" fn write_callback(
+ file: *mut bindings::file,
+ buf: *const core::ffi::c_char,
+ len: core::ffi::c_size_t,
+ offset: *mut bindings::loff_t,
+ ) -> core::ffi::c_ssize_t {
+ from_kernel_result! {
+ let mut data =
+ unsafe { UserSlicePtr::new(buf as *mut core::ffi::c_void, len).reader() };
+ // SAFETY: `private_data` was initialised by `open_callback` with a value returned by
+ // `T::Data::into_pointer`. `T::Data::from_pointer` is only called by the
+ // `release` callback, which the C API guarantees that will be called only when all
+ // references to `file` have been released, so we know it can't be called while this
+ // function is running.
+ let f = unsafe { T::Data::borrow((*file).private_data) };
+ // No `FMODE_UNSIGNED_OFFSET` support, so `offset` must be in [0, 2^63).
+ // See <https://github.com/fishinabarrel/linux-kernel-module-rust/pull/113>.
+ let written = T::write(
+ f,
+ unsafe { File::from_ptr(file) },
+ &mut data,
+ unsafe { *offset }.try_into()?,
+ )?;
+ unsafe { (*offset) += bindings::loff_t::try_from(written).unwrap() };
+ Ok(written as _)
+ }
+ }
+
+ unsafe extern "C" fn write_iter_callback(
+ iocb: *mut bindings::kiocb,
+ raw_iter: *mut bindings::iov_iter,
+ ) -> isize {
+ from_kernel_result! {
+ let mut iter = unsafe { IovIter::from_ptr(raw_iter) };
+ let file = unsafe { (*iocb).ki_filp };
+ let offset = unsafe { (*iocb).ki_pos };
+ // SAFETY: `private_data` was initialised by `open_callback` with a value returned by
+ // `T::Data::into_pointer`. `T::Data::from_pointer` is only called by the
+ // `release` callback, which the C API guarantees that will be called only when all
+ // references to `file` have been released, so we know it can't be called while this
+ // function is running.
+ let f = unsafe { T::Data::borrow((*file).private_data) };
+ let written = T::write(
+ f,
+ unsafe { File::from_ptr(file) },
+ &mut iter,
+ offset.try_into()?,
+ )?;
+ unsafe { (*iocb).ki_pos += bindings::loff_t::try_from(written).unwrap() };
+ Ok(written as _)
+ }
+ }
+
+ unsafe extern "C" fn release_callback(
+ _inode: *mut bindings::inode,
+ file: *mut bindings::file,
+ ) -> core::ffi::c_int {
+ let ptr = mem::replace(unsafe { &mut (*file).private_data }, ptr::null_mut());
+ T::release(unsafe { T::Data::from_pointer(ptr as _) }, unsafe {
+ File::from_ptr(file)
+ });
+ 0
+ }
+
+ unsafe extern "C" fn llseek_callback(
+ file: *mut bindings::file,
+ offset: bindings::loff_t,
+ whence: core::ffi::c_int,
+ ) -> bindings::loff_t {
+ from_kernel_result! {
+ let off = match whence as u32 {
+ bindings::SEEK_SET => SeekFrom::Start(offset.try_into()?),
+ bindings::SEEK_CUR => SeekFrom::Current(offset),
+ bindings::SEEK_END => SeekFrom::End(offset),
+ _ => return Err(EINVAL),
+ };
+ // SAFETY: `private_data` was initialised by `open_callback` with a value returned by
+ // `T::Data::into_pointer`. `T::Data::from_pointer` is only called by the
+ // `release` callback, which the C API guarantees that will be called only when all
+ // references to `file` have been released, so we know it can't be called while this
+ // function is running.
+ let f = unsafe { T::Data::borrow((*file).private_data) };
+ let off = T::seek(f, unsafe { File::from_ptr(file) }, off)?;
+ Ok(off as bindings::loff_t)
+ }
+ }
+
+ unsafe extern "C" fn unlocked_ioctl_callback(
+ file: *mut bindings::file,
+ cmd: core::ffi::c_uint,
+ arg: core::ffi::c_ulong,
+ ) -> core::ffi::c_long {
+ from_kernel_result! {
+ // SAFETY: `private_data` was initialised by `open_callback` with a value returned by
+ // `T::Data::into_pointer`. `T::Data::from_pointer` is only called by the
+ // `release` callback, which the C API guarantees that will be called only when all
+ // references to `file` have been released, so we know it can't be called while this
+ // function is running.
+ let f = unsafe { T::Data::borrow((*file).private_data) };
+ let mut cmd = IoctlCommand::new(cmd as _, arg as _);
+ let ret = T::ioctl(f, unsafe { File::from_ptr(file) }, &mut cmd)?;
+ Ok(ret as _)
+ }
+ }
+
+ unsafe extern "C" fn compat_ioctl_callback(
+ file: *mut bindings::file,
+ cmd: core::ffi::c_uint,
+ arg: core::ffi::c_ulong,
+ ) -> core::ffi::c_long {
+ from_kernel_result! {
+ // SAFETY: `private_data` was initialised by `open_callback` with a value returned by
+ // `T::Data::into_pointer`. `T::Data::from_pointer` is only called by the
+ // `release` callback, which the C API guarantees that will be called only when all
+ // references to `file` have been released, so we know it can't be called while this
+ // function is running.
+ let f = unsafe { T::Data::borrow((*file).private_data) };
+ let mut cmd = IoctlCommand::new(cmd as _, arg as _);
+ let ret = T::compat_ioctl(f, unsafe { File::from_ptr(file) }, &mut cmd)?;
+ Ok(ret as _)
+ }
+ }
+
+ unsafe extern "C" fn mmap_callback(
+ file: *mut bindings::file,
+ vma: *mut bindings::vm_area_struct,
+ ) -> core::ffi::c_int {
+ from_kernel_result! {
+ // SAFETY: `private_data` was initialised by `open_callback` with a value returned by
+ // `T::Data::into_pointer`. `T::Data::from_pointer` is only called by the
+ // `release` callback, which the C API guarantees that will be called only when all
+ // references to `file` have been released, so we know it can't be called while this
+ // function is running.
+ let f = unsafe { T::Data::borrow((*file).private_data) };
+
+ // SAFETY: The C API guarantees that `vma` is valid for the duration of this call.
+ // `area` only lives within this call, so it is guaranteed to be valid.
+ let mut area = unsafe { mm::virt::Area::from_ptr(vma) };
+
+ // SAFETY: The C API guarantees that `file` is valid for the duration of this call,
+ // which is longer than the lifetime of the file reference.
+ T::mmap(f, unsafe { File::from_ptr(file) }, &mut area)?;
+ Ok(0)
+ }
+ }
+
+ unsafe extern "C" fn fsync_callback(
+ file: *mut bindings::file,
+ start: bindings::loff_t,
+ end: bindings::loff_t,
+ datasync: core::ffi::c_int,
+ ) -> core::ffi::c_int {
+ from_kernel_result! {
+ let start = start.try_into()?;
+ let end = end.try_into()?;
+ let datasync = datasync != 0;
+ // SAFETY: `private_data` was initialised by `open_callback` with a value returned by
+ // `T::Data::into_pointer`. `T::Data::from_pointer` is only called by the
+ // `release` callback, which the C API guarantees that will be called only when all
+ // references to `file` have been released, so we know it can't be called while this
+ // function is running.
+ let f = unsafe { T::Data::borrow((*file).private_data) };
+ let res = T::fsync(f, unsafe { File::from_ptr(file) }, start, end, datasync)?;
+ Ok(res.try_into().unwrap())
+ }
+ }
+
+ unsafe extern "C" fn poll_callback(
+ file: *mut bindings::file,
+ wait: *mut bindings::poll_table_struct,
+ ) -> bindings::__poll_t {
+ // SAFETY: `private_data` was initialised by `open_callback` with a value returned by
+ // `T::Data::into_pointer`. `T::Data::from_pointer` is only called by the `release`
+ // callback, which the C API guarantees that will be called only when all references to
+ // `file` have been released, so we know it can't be called while this function is running.
+ let f = unsafe { T::Data::borrow((*file).private_data) };
+ match T::poll(f, unsafe { File::from_ptr(file) }, unsafe {
+ &PollTable::from_ptr(wait)
+ }) {
+ Ok(v) => v,
+ Err(_) => bindings::POLLERR,
+ }
+ }
+
+ const VTABLE: bindings::file_operations = bindings::file_operations {
+ open: Some(Self::open_callback),
+ release: Some(Self::release_callback),
+ read: if T::HAS_READ {
+ Some(Self::read_callback)
+ } else {
+ None
+ },
+ write: if T::HAS_WRITE {
+ Some(Self::write_callback)
+ } else {
+ None
+ },
+ llseek: if T::HAS_SEEK {
+ Some(Self::llseek_callback)
+ } else {
+ None
+ },
+
+ check_flags: None,
+ compat_ioctl: if T::HAS_COMPAT_IOCTL {
+ Some(Self::compat_ioctl_callback)
+ } else {
+ None
+ },
+ copy_file_range: None,
+ fallocate: None,
+ fadvise: None,
+ fasync: None,
+ flock: None,
+ flush: None,
+ fsync: if T::HAS_FSYNC {
+ Some(Self::fsync_callback)
+ } else {
+ None
+ },
+ get_unmapped_area: None,
+ iterate: None,
+ iterate_shared: None,
+ iopoll: None,
+ lock: None,
+ mmap: if T::HAS_MMAP {
+ Some(Self::mmap_callback)
+ } else {
+ None
+ },
+ mmap_supported_flags: 0,
+ owner: ptr::null_mut(),
+ poll: if T::HAS_POLL {
+ Some(Self::poll_callback)
+ } else {
+ None
+ },
+ read_iter: if T::HAS_READ {
+ Some(Self::read_iter_callback)
+ } else {
+ None
+ },
+ remap_file_range: None,
+ sendpage: None,
+ setlease: None,
+ show_fdinfo: None,
+ splice_read: None,
+ splice_write: None,
+ unlocked_ioctl: if T::HAS_IOCTL {
+ Some(Self::unlocked_ioctl_callback)
+ } else {
+ None
+ },
+ uring_cmd: None,
+ write_iter: if T::HAS_WRITE {
+ Some(Self::write_iter_callback)
+ } else {
+ None
+ },
+ };
+
+ /// Builds an instance of [`struct file_operations`].
+ ///
+ /// # Safety
+ ///
+ /// The caller must ensure that the adapter is compatible with the way the device is registered.
+ pub(crate) const unsafe fn build() -> &'static bindings::file_operations {
+ &Self::VTABLE
+ }
+}
+
+/// Allows the handling of ioctls defined with the `_IO`, `_IOR`, `_IOW`, and `_IOWR` macros.
+///
+/// For each macro, there is a handler function that takes the appropriate types as arguments.
+pub trait IoctlHandler: Sync {
+ /// The type of the first argument to each associated function.
+ type Target<'a>;
+
+ /// Handles ioctls defined with the `_IO` macro, that is, with no buffer as argument.
+ fn pure(_this: Self::Target<'_>, _file: &File, _cmd: u32, _arg: usize) -> Result<i32> {
+ Err(EINVAL)
+ }
+
+ /// Handles ioctls defined with the `_IOR` macro, that is, with an output buffer provided as
+ /// argument.
+ fn read(
+ _this: Self::Target<'_>,
+ _file: &File,
+ _cmd: u32,
+ _writer: &mut UserSlicePtrWriter,
+ ) -> Result<i32> {
+ Err(EINVAL)
+ }
+
+ /// Handles ioctls defined with the `_IOW` macro, that is, with an input buffer provided as
+ /// argument.
+ fn write(
+ _this: Self::Target<'_>,
+ _file: &File,
+ _cmd: u32,
+ _reader: &mut UserSlicePtrReader,
+ ) -> Result<i32> {
+ Err(EINVAL)
+ }
+
+ /// Handles ioctls defined with the `_IOWR` macro, that is, with a buffer for both input and
+ /// output provided as argument.
+ fn read_write(
+ _this: Self::Target<'_>,
+ _file: &File,
+ _cmd: u32,
+ _data: UserSlicePtr,
+ ) -> Result<i32> {
+ Err(EINVAL)
+ }
+}
+
+/// Represents an ioctl command.
+///
+/// It can use the components of an ioctl command to dispatch ioctls using
+/// [`IoctlCommand::dispatch`].
+pub struct IoctlCommand {
+ cmd: u32,
+ arg: usize,
+ user_slice: Option<UserSlicePtr>,
+}
+
+impl IoctlCommand {
+ /// Constructs a new [`IoctlCommand`].
+ fn new(cmd: u32, arg: usize) -> Self {
+ let size = (cmd >> bindings::_IOC_SIZESHIFT) & bindings::_IOC_SIZEMASK;
+
+ // SAFETY: We only create one instance of the user slice per ioctl call, so TOCTOU issues
+ // are not possible.
+ let user_slice = Some(unsafe { UserSlicePtr::new(arg as _, size as _) });
+ Self {
+ cmd,
+ arg,
+ user_slice,
+ }
+ }
+
+ /// Dispatches the given ioctl to the appropriate handler based on the value of the command. It
+ /// also creates a [`UserSlicePtr`], [`UserSlicePtrReader`], or [`UserSlicePtrWriter`]
+ /// depending on the direction of the buffer of the command.
+ ///
+ /// It is meant to be used in implementations of [`Operations::ioctl`] and
+ /// [`Operations::compat_ioctl`].
+ pub fn dispatch<T: IoctlHandler>(
+ &mut self,
+ handler: T::Target<'_>,
+ file: &File,
+ ) -> Result<i32> {
+ let dir = (self.cmd >> bindings::_IOC_DIRSHIFT) & bindings::_IOC_DIRMASK;
+ if dir == bindings::_IOC_NONE {
+ return T::pure(handler, file, self.cmd, self.arg);
+ }
+
+ let data = self.user_slice.take().ok_or(EINVAL)?;
+ const READ_WRITE: u32 = bindings::_IOC_READ | bindings::_IOC_WRITE;
+ match dir {
+ bindings::_IOC_WRITE => T::write(handler, file, self.cmd, &mut data.reader()),
+ bindings::_IOC_READ => T::read(handler, file, self.cmd, &mut data.writer()),
+ READ_WRITE => T::read_write(handler, file, self.cmd, data),
+ _ => Err(EINVAL),
+ }
+ }
+
+ /// Returns the raw 32-bit value of the command and the ptr-sized argument.
+ pub fn raw(&self) -> (u32, usize) {
+ (self.cmd, self.arg)
+ }
+}
+
+/// Trait for extracting file open arguments from kernel data structures.
+///
+/// This is meant to be implemented by registration managers.
+pub trait OpenAdapter<T: Sync> {
+ /// Converts untyped data stored in [`struct inode`] and [`struct file`] (when [`struct
+ /// file_operations::open`] is called) into the given type. For example, for `miscdev`
+ /// devices, a pointer to the registered [`struct miscdev`] is stored in [`struct
+ /// file::private_data`].
+ ///
+ /// # Safety
+ ///
+ /// This function must be called only when [`struct file_operations::open`] is being called for
+ /// a file that was registered by the implementer. The returned pointer must be valid and
+ /// not-null.
+ unsafe fn convert(_inode: *mut bindings::inode, _file: *mut bindings::file) -> *const T;
+}
+
+/// Corresponds to the kernel's `struct file_operations`.
+///
+/// You implement this trait whenever you would create a `struct file_operations`.
+///
+/// File descriptors may be used from multiple threads/processes concurrently, so your type must be
+/// [`Sync`]. It must also be [`Send`] because [`Operations::release`] will be called from the
+/// thread that decrements that associated file's refcount to zero.
+#[vtable]
+pub trait Operations {
+ /// The type of the context data returned by [`Operations::open`] and made available to
+ /// other methods.
+ type Data: PointerWrapper + Send + Sync = ();
+
+ /// The type of the context data passed to [`Operations::open`].
+ type OpenData: Sync = ();
+
+ /// Creates a new instance of this file.
+ ///
+ /// Corresponds to the `open` function pointer in `struct file_operations`.
+ fn open(context: &Self::OpenData, file: &File) -> Result<Self::Data>;
+
+ /// Cleans up after the last reference to the file goes away.
+ ///
+ /// Note that context data is moved, so it will be freed automatically unless the
+ /// implementation moves it elsewhere.
+ ///
+ /// Corresponds to the `release` function pointer in `struct file_operations`.
+ fn release(_data: Self::Data, _file: &File) {}
+
+ /// Reads data from this file to the caller's buffer.
+ ///
+ /// Corresponds to the `read` and `read_iter` function pointers in `struct file_operations`.
+ fn read(
+ _data: <Self::Data as PointerWrapper>::Borrowed<'_>,
+ _file: &File,
+ _writer: &mut impl IoBufferWriter,
+ _offset: u64,
+ ) -> Result<usize> {
+ Err(EINVAL)
+ }
+
+ /// Writes data from the caller's buffer to this file.
+ ///
+ /// Corresponds to the `write` and `write_iter` function pointers in `struct file_operations`.
+ fn write(
+ _data: <Self::Data as PointerWrapper>::Borrowed<'_>,
+ _file: &File,
+ _reader: &mut impl IoBufferReader,
+ _offset: u64,
+ ) -> Result<usize> {
+ Err(EINVAL)
+ }
+
+ /// Changes the position of the file.
+ ///
+ /// Corresponds to the `llseek` function pointer in `struct file_operations`.
+ fn seek(
+ _data: <Self::Data as PointerWrapper>::Borrowed<'_>,
+ _file: &File,
+ _offset: SeekFrom,
+ ) -> Result<u64> {
+ Err(EINVAL)
+ }
+
+ /// Performs IO control operations that are specific to the file.
+ ///
+ /// Corresponds to the `unlocked_ioctl` function pointer in `struct file_operations`.
+ fn ioctl(
+ _data: <Self::Data as PointerWrapper>::Borrowed<'_>,
+ _file: &File,
+ _cmd: &mut IoctlCommand,
+ ) -> Result<i32> {
+ Err(ENOTTY)
+ }
+
+ /// Performs 32-bit IO control operations on that are specific to the file on 64-bit kernels.
+ ///
+ /// Corresponds to the `compat_ioctl` function pointer in `struct file_operations`.
+ fn compat_ioctl(
+ _data: <Self::Data as PointerWrapper>::Borrowed<'_>,
+ _file: &File,
+ _cmd: &mut IoctlCommand,
+ ) -> Result<i32> {
+ Err(ENOTTY)
+ }
+
+ /// Syncs pending changes to this file.
+ ///
+ /// Corresponds to the `fsync` function pointer in `struct file_operations`.
+ fn fsync(
+ _data: <Self::Data as PointerWrapper>::Borrowed<'_>,
+ _file: &File,
+ _start: u64,
+ _end: u64,
+ _datasync: bool,
+ ) -> Result<u32> {
+ Err(EINVAL)
+ }
+
+ /// Maps areas of the caller's virtual memory with device/file memory.
+ ///
+ /// Corresponds to the `mmap` function pointer in `struct file_operations`.
+ fn mmap(
+ _data: <Self::Data as PointerWrapper>::Borrowed<'_>,
+ _file: &File,
+ _vma: &mut mm::virt::Area,
+ ) -> Result {
+ Err(EINVAL)
+ }
+
+ /// Checks the state of the file and optionally registers for notification when the state
+ /// changes.
+ ///
+ /// Corresponds to the `poll` function pointer in `struct file_operations`.
+ fn poll(
+ _data: <Self::Data as PointerWrapper>::Borrowed<'_>,
+ _file: &File,
+ _table: &PollTable,
+ ) -> Result<u32> {
+ Ok(bindings::POLLIN | bindings::POLLOUT | bindings::POLLRDNORM | bindings::POLLWRNORM)
+ }
+}
diff --git a/rust/kernel/fs.rs b/rust/kernel/fs.rs
new file mode 100644
index 000000000000..46dc38aad2bc
--- /dev/null
+++ b/rust/kernel/fs.rs
@@ -0,0 +1,846 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! File systems.
+//!
+//! C headers: [`include/linux/fs.h`](../../../../include/linux/fs.h)
+
+use crate::{
+ bindings, error::code::*, error::from_kernel_result, str::CStr, to_result,
+ types::PointerWrapper, AlwaysRefCounted, Error, Result, ScopeGuard, ThisModule,
+};
+use alloc::boxed::Box;
+use core::{
+ cell::UnsafeCell,
+ marker::{PhantomData, PhantomPinned},
+ pin::Pin,
+ ptr,
+};
+use macros::vtable;
+
+pub mod param;
+
+/// Type of superblock keying.
+///
+/// It determines how C's `fs_context_operations::get_tree` is implemented.
+pub enum Super {
+ /// Only one such superblock may exist.
+ Single,
+
+ /// As [`Super::Single`], but reconfigure if it exists.
+ SingleReconf,
+
+ /// Superblocks with different data pointers may exist.
+ Keyed,
+
+ /// Multiple independent superblocks may exist.
+ Independent,
+
+ /// Uses a block device.
+ BlockDev,
+}
+
+/// A file system context.
+///
+/// It is used to gather configuration to then mount or reconfigure a file system.
+#[vtable]
+pub trait Context<T: Type + ?Sized> {
+ /// Type of the data associated with the context.
+ type Data: PointerWrapper + Send + Sync + 'static;
+
+ /// The typed file system parameters.
+ ///
+ /// Users are encouraged to define it using the [`crate::define_fs_params`] macro.
+ const PARAMS: param::SpecTable<'static, Self::Data> = param::SpecTable::empty();
+
+ /// Creates a new context.
+ fn try_new() -> Result<Self::Data>;
+
+ /// Parses a parameter that wasn't specified in [`Self::PARAMS`].
+ fn parse_unknown_param(
+ _data: &mut Self::Data,
+ _name: &CStr,
+ _value: param::Value<'_>,
+ ) -> Result {
+ Err(ENOPARAM)
+ }
+
+ /// Parses the whole parameter block, potentially skipping regular handling for parts of it.
+ ///
+ /// The return value is the portion of the input buffer for which the regular handling
+ /// (involving [`Self::PARAMS`] and [`Self::parse_unknown_param`]) will still be carried out.
+ /// If it's `None`, the regular handling is not performed at all.
+ fn parse_monolithic<'a>(
+ _data: &mut Self::Data,
+ _buf: Option<&'a mut [u8]>,
+ ) -> Result<Option<&'a mut [u8]>> {
+ Ok(None)
+ }
+
+ /// Returns the superblock data to be used by this file system context.
+ ///
+ /// This is only needed when [`Type::SUPER_TYPE`] is [`Super::Keyed`], otherwise it is never
+ /// called. In the former case, when the fs is being mounted, an existing superblock is reused
+ /// if one can be found with the same data as the returned value; otherwise a new superblock is
+ /// created.
+ fn tree_key(_data: &mut Self::Data) -> Result<T::Data> {
+ Err(ENOTSUPP)
+ }
+}
+
+struct Tables<T: Type + ?Sized>(T);
+impl<T: Type + ?Sized> Tables<T> {
+ const CONTEXT: bindings::fs_context_operations = bindings::fs_context_operations {
+ free: Some(Self::free_callback),
+ parse_param: Some(Self::parse_param_callback),
+ get_tree: Some(Self::get_tree_callback),
+ reconfigure: Some(Self::reconfigure_callback),
+ parse_monolithic: if <T::Context as Context<T>>::HAS_PARSE_MONOLITHIC {
+ Some(Self::parse_monolithic_callback)
+ } else {
+ None
+ },
+ dup: None,
+ };
+
+ unsafe extern "C" fn free_callback(fc: *mut bindings::fs_context) {
+ // SAFETY: The callback contract guarantees that `fc` is valid.
+ let fc = unsafe { &*fc };
+
+ let ptr = fc.fs_private;
+ if !ptr.is_null() {
+ // SAFETY: `fs_private` was initialised with the result of a `to_pointer` call in
+ // `init_fs_context_callback`, so it's ok to call `from_pointer` here.
+ unsafe { <T::Context as Context<T>>::Data::from_pointer(ptr) };
+ }
+
+ let ptr = fc.s_fs_info;
+ if !ptr.is_null() {
+ // SAFETY: `s_fs_info` may be initialised with the result of a `to_pointer` call in
+ // `get_tree_callback` when keyed superblocks are used (`get_tree_keyed` sets it), so
+ // it's ok to call `from_pointer` here.
+ unsafe { T::Data::from_pointer(ptr) };
+ }
+ }
+
+ unsafe extern "C" fn parse_param_callback(
+ fc: *mut bindings::fs_context,
+ param: *mut bindings::fs_parameter,
+ ) -> core::ffi::c_int {
+ from_kernel_result! {
+ // SAFETY: The callback contract guarantees that `fc` is valid.
+ let ptr = unsafe { (*fc).fs_private };
+
+ // SAFETY: The value of `ptr` (coming from `fs_private` was initialised in
+ // `init_fs_context_callback` to the result of an `into_pointer` call. Since the
+ // context is valid, `from_pointer` wasn't called yet, so `ptr` is valid. Additionally,
+ // the callback contract guarantees that callbacks are serialised, so it is ok to
+ // mutably reference it.
+ let mut data =
+ unsafe { <<T::Context as Context<T>>::Data as PointerWrapper>::borrow_mut(ptr) };
+ let mut result = bindings::fs_parse_result::default();
+ // SAFETY: All parameters are valid at least for the duration of the call.
+ let opt =
+ unsafe { bindings::fs_parse(fc, T::Context::PARAMS.first, param, &mut result) };
+
+ // SAFETY: The callback contract guarantees that `param` is valid for the duration of
+ // the callback.
+ let param = unsafe { &*param };
+ if opt >= 0 {
+ let opt = opt as usize;
+ if opt >= T::Context::PARAMS.handlers.len() {
+ return Err(EINVAL);
+ }
+ T::Context::PARAMS.handlers[opt].handle_param(&mut data, param, &result)?;
+ return Ok(0);
+ }
+
+ if opt != ENOPARAM.to_kernel_errno() {
+ return Err(Error::from_kernel_errno(opt));
+ }
+
+ if !T::Context::HAS_PARSE_UNKNOWN_PARAM {
+ return Err(ENOPARAM);
+ }
+
+ let val = param::Value::from_fs_parameter(param);
+ // SAFETY: The callback contract guarantees the parameter key to be valid and last at
+ // least the duration of the callback.
+ T::Context::parse_unknown_param(
+ &mut data,
+ unsafe { CStr::from_char_ptr(param.key) },
+ val,
+ )?;
+ Ok(0)
+ }
+ }
+
+ unsafe extern "C" fn fill_super_callback(
+ sb_ptr: *mut bindings::super_block,
+ fc: *mut bindings::fs_context,
+ ) -> core::ffi::c_int {
+ from_kernel_result! {
+ // SAFETY: The callback contract guarantees that `fc` is valid. It also guarantees that
+ // the callbacks are serialised for a given `fc`, so it is safe to mutably dereference
+ // it.
+ let fc = unsafe { &mut *fc };
+ let ptr = core::mem::replace(&mut fc.fs_private, ptr::null_mut());
+
+ // SAFETY: The value of `ptr` (coming from `fs_private` was initialised in
+ // `init_fs_context_callback` to the result of an `into_pointer` call. The context is
+ // being used to initialise a superblock, so we took over `ptr` (`fs_private` is set to
+ // null now) and call `from_pointer` below.
+ let data =
+ unsafe { <<T::Context as Context<T>>::Data as PointerWrapper>::from_pointer(ptr) };
+
+ // SAFETY: The callback contract guarantees that `sb_ptr` is a unique pointer to a
+ // newly-created superblock.
+ let newsb = unsafe { NewSuperBlock::new(sb_ptr) };
+ T::fill_super(data, newsb)?;
+ Ok(0)
+ }
+ }
+
+ unsafe extern "C" fn get_tree_callback(fc: *mut bindings::fs_context) -> core::ffi::c_int {
+ // N.B. When new types are added below, we may need to update `kill_sb_callback` to ensure
+ // that we're cleaning up properly.
+ match T::SUPER_TYPE {
+ Super::Single => unsafe {
+ // SAFETY: `fc` is valid per the callback contract. `fill_super_callback` also has
+ // the right type and is a valid callback.
+ bindings::get_tree_single(fc, Some(Self::fill_super_callback))
+ },
+ Super::SingleReconf => unsafe {
+ // SAFETY: `fc` is valid per the callback contract. `fill_super_callback` also has
+ // the right type and is a valid callback.
+ bindings::get_tree_single_reconf(fc, Some(Self::fill_super_callback))
+ },
+ Super::Independent => unsafe {
+ // SAFETY: `fc` is valid per the callback contract. `fill_super_callback` also has
+ // the right type and is a valid callback.
+ bindings::get_tree_nodev(fc, Some(Self::fill_super_callback))
+ },
+ Super::BlockDev => unsafe {
+ // SAFETY: `fc` is valid per the callback contract. `fill_super_callback` also has
+ // the right type and is a valid callback.
+ bindings::get_tree_bdev(fc, Some(Self::fill_super_callback))
+ },
+ Super::Keyed => {
+ from_kernel_result! {
+ // SAFETY: `fc` is valid per the callback contract.
+ let ctx = unsafe { &*fc };
+ let ptr = ctx.fs_private;
+
+ // SAFETY: The value of `ptr` (coming from `fs_private` was initialised in
+ // `init_fs_context_callback` to the result of an `into_pointer` call. Since
+ // the context is valid, `from_pointer` wasn't called yet, so `ptr` is valid.
+ // Additionally, the callback contract guarantees that callbacks are
+ // serialised, so it is ok to mutably reference it.
+ let mut data = unsafe {
+ <<T::Context as Context<T>>::Data as PointerWrapper>::borrow_mut(ptr)
+ };
+ let fs_data = T::Context::tree_key(&mut data)?;
+ let fs_data_ptr = fs_data.into_pointer();
+
+ // `get_tree_keyed` reassigns `ctx.s_fs_info`, which should be ok because
+ // nowhere else is it assigned a non-null value. However, we add the assert
+ // below to ensure that there are no unexpected paths on the C side that may do
+ // this.
+ assert_eq!(ctx.s_fs_info, core::ptr::null_mut());
+
+ // SAFETY: `fc` is valid per the callback contract. `fill_super_callback` also
+ // has the right type and is a valid callback. Lastly, we just called
+ // `into_pointer` above, so `fs_data_ptr` is also valid.
+ to_result(unsafe {
+ bindings::get_tree_keyed(
+ fc,
+ Some(Self::fill_super_callback),
+ fs_data_ptr as _,
+ )
+ })?;
+ Ok(0)
+ }
+ }
+ }
+ }
+
+ unsafe extern "C" fn reconfigure_callback(_fc: *mut bindings::fs_context) -> core::ffi::c_int {
+ EINVAL.to_kernel_errno()
+ }
+
+ unsafe extern "C" fn parse_monolithic_callback(
+ fc: *mut bindings::fs_context,
+ buf: *mut core::ffi::c_void,
+ ) -> core::ffi::c_int {
+ from_kernel_result! {
+ // SAFETY: The callback contract guarantees that `fc` is valid.
+ let ptr = unsafe { (*fc).fs_private };
+
+ // SAFETY: The value of `ptr` (coming from `fs_private` was initialised in
+ // `init_fs_context_callback` to the result of an `into_pointer` call. Since the
+ // context is valid, `from_pointer` wasn't called yet, so `ptr` is valid. Additionally,
+ // the callback contract guarantees that callbacks are serialised, so it is ok to
+ // mutably reference it.
+ let mut data =
+ unsafe { <<T::Context as Context<T>>::Data as PointerWrapper>::borrow_mut(ptr) };
+ let page = if buf.is_null() {
+ None
+ } else {
+ // SAFETY: This callback is called to handle the `mount` syscall, which takes a
+ // page-sized buffer as data.
+ Some(unsafe { &mut *ptr::slice_from_raw_parts_mut(buf.cast(), crate::PAGE_SIZE) })
+ };
+ let regular = T::Context::parse_monolithic(&mut data, page)?;
+ if let Some(buf) = regular {
+ // SAFETY: Both `fc` and `buf` are guaranteed to be valid; the former because the
+ // callback is still ongoing and the latter because its lifefime is tied to that of
+ // `page`, which is also valid for the duration of the callback.
+ to_result(unsafe {
+ bindings::generic_parse_monolithic(fc, buf.as_mut_ptr().cast())
+ })?;
+ }
+ Ok(0)
+ }
+ }
+
+ const SUPER_BLOCK: bindings::super_operations = bindings::super_operations {
+ alloc_inode: None,
+ destroy_inode: None,
+ free_inode: None,
+ dirty_inode: None,
+ write_inode: None,
+ drop_inode: None,
+ evict_inode: None,
+ put_super: None,
+ sync_fs: None,
+ freeze_super: None,
+ freeze_fs: None,
+ thaw_super: None,
+ unfreeze_fs: None,
+ statfs: None,
+ remount_fs: None,
+ umount_begin: None,
+ show_options: None,
+ show_devname: None,
+ show_path: None,
+ show_stats: None,
+ #[cfg(CONFIG_QUOTA)]
+ quota_read: None,
+ #[cfg(CONFIG_QUOTA)]
+ quota_write: None,
+ #[cfg(CONFIG_QUOTA)]
+ get_dquots: None,
+ nr_cached_objects: None,
+ free_cached_objects: None,
+ };
+}
+
+/// A file system type.
+pub trait Type {
+ /// The context used to build fs configuration before it is mounted or reconfigured.
+ type Context: Context<Self> + ?Sized;
+
+ /// Data associated with each file system instance.
+ type Data: PointerWrapper + Send + Sync = ();
+
+ /// Determines how superblocks for this file system type are keyed.
+ const SUPER_TYPE: Super;
+
+ /// The name of the file system type.
+ const NAME: &'static CStr;
+
+ /// The flags of this file system type.
+ ///
+ /// It is a combination of the flags in the [`flags`] module.
+ const FLAGS: i32;
+
+ /// Initialises a super block for this file system type.
+ fn fill_super(
+ data: <Self::Context as Context<Self>>::Data,
+ sb: NewSuperBlock<'_, Self>,
+ ) -> Result<&SuperBlock<Self>>;
+}
+
+/// File system flags.
+pub mod flags {
+ use crate::bindings;
+
+ /// The file system requires a device.
+ pub const REQUIRES_DEV: i32 = bindings::FS_REQUIRES_DEV as _;
+
+ /// The options provided when mounting are in binary form.
+ pub const BINARY_MOUNTDATA: i32 = bindings::FS_BINARY_MOUNTDATA as _;
+
+ /// The file system has a subtype. It is extracted from the name and passed in as a parameter.
+ pub const HAS_SUBTYPE: i32 = bindings::FS_HAS_SUBTYPE as _;
+
+ /// The file system can be mounted by userns root.
+ pub const USERNS_MOUNT: i32 = bindings::FS_USERNS_MOUNT as _;
+
+ /// Disables fanotify permission events.
+ pub const DISALLOW_NOTIFY_PERM: i32 = bindings::FS_DISALLOW_NOTIFY_PERM as _;
+
+ /// The file system has been updated to handle vfs idmappings.
+ pub const ALLOW_IDMAP: i32 = bindings::FS_ALLOW_IDMAP as _;
+
+ /// The file systen will handle `d_move` during `rename` internally.
+ pub const RENAME_DOES_D_MOVE: i32 = bindings::FS_RENAME_DOES_D_MOVE as _;
+}
+
+/// A file system registration.
+#[derive(Default)]
+pub struct Registration {
+ is_registered: bool,
+ fs: UnsafeCell<bindings::file_system_type>,
+ _pin: PhantomPinned,
+}
+
+// SAFETY: `Registration` doesn't really provide any `&self` methods, so it is safe to pass
+// references to it around.
+unsafe impl Sync for Registration {}
+
+// SAFETY: Both registration and unregistration are implemented in C and safe to be performed from
+// any thread, so `Registration` is `Send`.
+unsafe impl Send for Registration {}
+
+impl Registration {
+ /// Creates a new file system registration.
+ ///
+ /// It is not visible or accessible yet. A successful call to [`Registration::register`] needs
+ /// to be made before users can mount it.
+ pub fn new() -> Self {
+ Self {
+ is_registered: false,
+ fs: UnsafeCell::new(bindings::file_system_type::default()),
+ _pin: PhantomPinned,
+ }
+ }
+
+ /// Registers a file system so that it can be mounted by users.
+ ///
+ /// The file system is described by the [`Type`] argument.
+ ///
+ /// It is automatically unregistered when the registration is dropped.
+ pub fn register<T: Type + ?Sized>(self: Pin<&mut Self>, module: &'static ThisModule) -> Result {
+ // SAFETY: We never move out of `this`.
+ let this = unsafe { self.get_unchecked_mut() };
+
+ if this.is_registered {
+ return Err(EINVAL);
+ }
+
+ let mut fs = this.fs.get_mut();
+ fs.owner = module.0;
+ fs.name = T::NAME.as_char_ptr();
+ fs.fs_flags = T::FLAGS;
+ fs.parameters = T::Context::PARAMS.first;
+ fs.init_fs_context = Some(Self::init_fs_context_callback::<T>);
+ fs.kill_sb = Some(Self::kill_sb_callback::<T>);
+
+ // SAFETY: This block registers all fs type keys with lockdep. We just need the memory
+ // locations to be owned by the caller, which is the case.
+ unsafe {
+ bindings::lockdep_register_key(&mut fs.s_lock_key);
+ bindings::lockdep_register_key(&mut fs.s_umount_key);
+ bindings::lockdep_register_key(&mut fs.s_vfs_rename_key);
+ bindings::lockdep_register_key(&mut fs.i_lock_key);
+ bindings::lockdep_register_key(&mut fs.i_mutex_key);
+ bindings::lockdep_register_key(&mut fs.invalidate_lock_key);
+ bindings::lockdep_register_key(&mut fs.i_mutex_dir_key);
+ for key in &mut fs.s_writers_key {
+ bindings::lockdep_register_key(key);
+ }
+ }
+
+ let ptr = this.fs.get();
+
+ // SAFETY: `ptr` as valid as it points to the `self.fs`.
+ let key_guard = ScopeGuard::new(|| unsafe { Self::unregister_keys(ptr) });
+
+ // SAFETY: Pointers stored in `fs` are either static so will live for as long as the
+ // registration is active (it is undone in `drop`).
+ to_result(unsafe { bindings::register_filesystem(ptr) })?;
+ key_guard.dismiss();
+ this.is_registered = true;
+ Ok(())
+ }
+
+ /// Unregisters the lockdep keys in the file system type.
+ ///
+ /// # Safety
+ ///
+ /// `fs` must be non-null and valid.
+ unsafe fn unregister_keys(fs: *mut bindings::file_system_type) {
+ // SAFETY: This block unregisters all fs type keys from lockdep. They must have been
+ // registered before.
+ unsafe {
+ bindings::lockdep_unregister_key(ptr::addr_of_mut!((*fs).s_lock_key));
+ bindings::lockdep_unregister_key(ptr::addr_of_mut!((*fs).s_umount_key));
+ bindings::lockdep_unregister_key(ptr::addr_of_mut!((*fs).s_vfs_rename_key));
+ bindings::lockdep_unregister_key(ptr::addr_of_mut!((*fs).i_lock_key));
+ bindings::lockdep_unregister_key(ptr::addr_of_mut!((*fs).i_mutex_key));
+ bindings::lockdep_unregister_key(ptr::addr_of_mut!((*fs).invalidate_lock_key));
+ bindings::lockdep_unregister_key(ptr::addr_of_mut!((*fs).i_mutex_dir_key));
+ for i in 0..(*fs).s_writers_key.len() {
+ bindings::lockdep_unregister_key(ptr::addr_of_mut!((*fs).s_writers_key[i]));
+ }
+ }
+ }
+
+ unsafe extern "C" fn init_fs_context_callback<T: Type + ?Sized>(
+ fc_ptr: *mut bindings::fs_context,
+ ) -> core::ffi::c_int {
+ from_kernel_result! {
+ let data = T::Context::try_new()?;
+ // SAFETY: The callback contract guarantees that `fc_ptr` is the only pointer to a
+ // newly-allocated fs context, so it is safe to mutably reference it.
+ let fc = unsafe { &mut *fc_ptr };
+ fc.fs_private = data.into_pointer() as _;
+ fc.ops = &Tables::<T>::CONTEXT;
+ Ok(0)
+ }
+ }
+
+ unsafe extern "C" fn kill_sb_callback<T: Type + ?Sized>(sb_ptr: *mut bindings::super_block) {
+ if let Super::BlockDev = T::SUPER_TYPE {
+ // SAFETY: When the superblock type is `BlockDev`, we have a block device so it's safe
+ // to call `kill_block_super`. Additionally, the callback contract guarantees that
+ // `sb_ptr` is valid.
+ unsafe { bindings::kill_block_super(sb_ptr) }
+ } else {
+ // SAFETY: We always call a `get_tree_nodev` variant from `get_tree_callback` without a
+ // device when `T::SUPER_TYPE` is not `BlockDev`, so we never have a device in such
+ // cases, therefore it is ok to call the function below. Additionally, the callback
+ // contract guarantees that `sb_ptr` is valid.
+ unsafe { bindings::kill_anon_super(sb_ptr) }
+ }
+
+ // SAFETY: The callback contract guarantees that `sb_ptr` is valid.
+ let sb = unsafe { &*sb_ptr };
+
+ // SAFETY: The `kill_sb` callback being called implies that the `s_type` field is valid.
+ unsafe { Self::unregister_keys(sb.s_type) };
+
+ let ptr = sb.s_fs_info;
+ if !ptr.is_null() {
+ // SAFETY: The only place where `s_fs_info` is assigned is `NewSuperBlock::init`, where
+ // it's initialised with the result of a `to_pointer` call. We checked above that ptr
+ // is non-null because it would be null if we never reached the point where we init the
+ // field.
+ unsafe { T::Data::from_pointer(ptr) };
+ }
+ }
+}
+
+impl Drop for Registration {
+ fn drop(&mut self) {
+ if self.is_registered {
+ // SAFETY: When `is_registered` is `true`, a previous call to `register_filesystem` has
+ // succeeded, so it is safe to unregister here.
+ unsafe { bindings::unregister_filesystem(self.fs.get()) };
+ }
+ }
+}
+
+/// State of [`NewSuperBlock`] that indicates that [`NewSuperBlock::init`] needs to be called
+/// eventually.
+pub struct NeedsInit;
+
+/// State of [`NewSuperBlock`] that indicates that [`NewSuperBlock::init_root`] needs to be called
+/// eventually.
+pub struct NeedsRoot;
+
+/// Required superblock parameters.
+///
+/// This is used in [`NewSuperBlock::init`].
+pub struct SuperParams {
+ /// The magic number of the superblock.
+ pub magic: u32,
+
+ /// The size of a block in powers of 2 (i.e., for a value of `n`, the size is `2^n`.
+ pub blocksize_bits: u8,
+
+ /// Maximum size of a file.
+ pub maxbytes: i64,
+
+ /// Granularity of c/m/atime in ns (cannot be worse than a second).
+ pub time_gran: u32,
+}
+
+impl SuperParams {
+ /// Default value for instances of [`SuperParams`].
+ pub const DEFAULT: Self = Self {
+ magic: 0,
+ blocksize_bits: crate::PAGE_SIZE as _,
+ maxbytes: bindings::MAX_LFS_FILESIZE,
+ time_gran: 1,
+ };
+}
+
+/// A superblock that is still being initialised.
+///
+/// It uses type states to ensure that callers use the right sequence of calls.
+///
+/// # Invariants
+///
+/// The superblock is a newly-created one and this is the only active pointer to it.
+pub struct NewSuperBlock<'a, T: Type + ?Sized, S = NeedsInit> {
+ sb: *mut bindings::super_block,
+ _p: PhantomData<(&'a T, S)>,
+}
+
+impl<'a, T: Type + ?Sized> NewSuperBlock<'a, T, NeedsInit> {
+ /// Creates a new instance of [`NewSuperBlock`].
+ ///
+ /// # Safety
+ ///
+ /// `sb` must point to a newly-created superblock and it must be the only active pointer to it.
+ unsafe fn new(sb: *mut bindings::super_block) -> Self {
+ // INVARIANT: The invariants are satisfied by the safety requirements of this function.
+ Self {
+ sb,
+ _p: PhantomData,
+ }
+ }
+
+ /// Initialises the superblock so that it transitions to the [`NeedsRoot`] type state.
+ pub fn init(
+ self,
+ data: T::Data,
+ params: &SuperParams,
+ ) -> Result<NewSuperBlock<'a, T, NeedsRoot>> {
+ // SAFETY: The type invariant guarantees that `self.sb` is the only pointer to a
+ // newly-allocated superblock, so it is safe to mutably reference it.
+ let sb = unsafe { &mut *self.sb };
+
+ sb.s_magic = params.magic as _;
+ sb.s_op = &Tables::<T>::SUPER_BLOCK;
+ sb.s_maxbytes = params.maxbytes;
+ sb.s_time_gran = params.time_gran;
+ sb.s_blocksize_bits = params.blocksize_bits;
+ sb.s_blocksize = 1;
+ if sb.s_blocksize.leading_zeros() < params.blocksize_bits.into() {
+ return Err(EINVAL);
+ }
+ sb.s_blocksize = 1 << sb.s_blocksize_bits;
+
+ // Keyed file systems already have `s_fs_info` initialised.
+ let info = data.into_pointer() as *mut _;
+ if let Super::Keyed = T::SUPER_TYPE {
+ // SAFETY: We just called `into_pointer` above.
+ unsafe { T::Data::from_pointer(info) };
+
+ if sb.s_fs_info != info {
+ return Err(EINVAL);
+ }
+ } else {
+ sb.s_fs_info = info;
+ }
+
+ Ok(NewSuperBlock {
+ sb: self.sb,
+ _p: PhantomData,
+ })
+ }
+}
+
+impl<'a, T: Type + ?Sized> NewSuperBlock<'a, T, NeedsRoot> {
+ /// Initialises the root of the superblock.
+ pub fn init_root(self) -> Result<&'a SuperBlock<T>> {
+ // The following is temporary code to create the root inode and dentry. It will be replaced
+ // once we allow inodes and dentries to be created directly from Rust code.
+
+ // SAFETY: `sb` is initialised (`NeedsRoot` typestate implies it), so it is safe to pass it
+ // to `new_inode`.
+ let inode = unsafe { bindings::new_inode(self.sb) };
+ if inode.is_null() {
+ return Err(ENOMEM);
+ }
+
+ {
+ // SAFETY: This is a newly-created inode. No other references to it exist, so it is
+ // safe to mutably dereference it.
+ let inode = unsafe { &mut *inode };
+
+ // SAFETY: `current_time` requires that `inode.sb` be valid, which is the case here
+ // since we allocated the inode through the superblock.
+ let time = unsafe { bindings::current_time(inode) };
+ inode.i_ino = 1;
+ inode.i_mode = (bindings::S_IFDIR | 0o755) as _;
+ inode.i_mtime = time;
+ inode.i_atime = time;
+ inode.i_ctime = time;
+
+ // SAFETY: `simple_dir_operations` never changes, it's safe to reference it.
+ inode.__bindgen_anon_3.i_fop = unsafe { &bindings::simple_dir_operations };
+
+ // SAFETY: `simple_dir_inode_operations` never changes, it's safe to reference it.
+ inode.i_op = unsafe { &bindings::simple_dir_inode_operations };
+
+ // SAFETY: `inode` is valid for write.
+ unsafe { bindings::set_nlink(inode, 2) };
+ }
+
+ // SAFETY: `d_make_root` requires that `inode` be valid and referenced, which is the
+ // case for this call.
+ //
+ // It takes over the inode, even on failure, so we don't need to clean it up.
+ let dentry = unsafe { bindings::d_make_root(inode) };
+ if dentry.is_null() {
+ return Err(ENOMEM);
+ }
+
+ // SAFETY: The typestate guarantees that `self.sb` is valid.
+ unsafe { (*self.sb).s_root = dentry };
+
+ // SAFETY: The typestate guarantees that `self.sb` is initialised and we just finished
+ // setting its root, so it's a fully ready superblock.
+ Ok(unsafe { &mut *self.sb.cast() })
+ }
+}
+
+/// A file system super block.
+///
+/// Wraps the kernel's `struct super_block`.
+#[repr(transparent)]
+pub struct SuperBlock<T: Type + ?Sized>(
+ pub(crate) UnsafeCell<bindings::super_block>,
+ PhantomData<T>,
+);
+
+/// Wraps the kernel's `struct inode`.
+///
+/// # Invariants
+///
+/// Instances of this type are always ref-counted, that is, a call to `ihold` ensures that the
+/// allocation remains valid at least until the matching call to `iput`.
+#[repr(transparent)]
+pub struct INode(pub(crate) UnsafeCell<bindings::inode>);
+
+// SAFETY: The type invariants guarantee that `INode` is always ref-counted.
+unsafe impl AlwaysRefCounted for INode {
+ fn inc_ref(&self) {
+ // SAFETY: The existence of a shared reference means that the refcount is nonzero.
+ unsafe { bindings::ihold(self.0.get()) };
+ }
+
+ unsafe fn dec_ref(obj: ptr::NonNull<Self>) {
+ // SAFETY: The safety requirements guarantee that the refcount is nonzero.
+ unsafe { bindings::iput(obj.cast().as_ptr()) }
+ }
+}
+
+/// Wraps the kernel's `struct dentry`.
+///
+/// # Invariants
+///
+/// Instances of this type are always ref-counted, that is, a call to `dget` ensures that the
+/// allocation remains valid at least until the matching call to `dput`.
+#[repr(transparent)]
+pub struct DEntry(pub(crate) UnsafeCell<bindings::dentry>);
+
+// SAFETY: The type invariants guarantee that `DEntry` is always ref-counted.
+unsafe impl AlwaysRefCounted for DEntry {
+ fn inc_ref(&self) {
+ // SAFETY: The existence of a shared reference means that the refcount is nonzero.
+ unsafe { bindings::dget(self.0.get()) };
+ }
+
+ unsafe fn dec_ref(obj: ptr::NonNull<Self>) {
+ // SAFETY: The safety requirements guarantee that the refcount is nonzero.
+ unsafe { bindings::dput(obj.cast().as_ptr()) }
+ }
+}
+
+/// Wraps the kernel's `struct filename`.
+#[repr(transparent)]
+pub struct Filename(pub(crate) UnsafeCell<bindings::filename>);
+
+impl Filename {
+ /// Creates a reference to a [`Filename`] from a valid pointer.
+ ///
+ /// # Safety
+ ///
+ /// The caller must ensure that `ptr` is valid and remains valid for the lifetime of the
+ /// returned [`Filename`] instance.
+ pub(crate) unsafe fn from_ptr<'a>(ptr: *const bindings::filename) -> &'a Filename {
+ // SAFETY: The safety requirements guarantee the validity of the dereference, while the
+ // `Filename` type being transparent makes the cast ok.
+ unsafe { &*ptr.cast() }
+ }
+}
+
+/// Kernel module that exposes a single file system implemented by `T`.
+pub struct Module<T: Type> {
+ _fs: Pin<Box<Registration>>,
+ _p: PhantomData<T>,
+}
+
+impl<T: Type + Sync> crate::Module for Module<T> {
+ fn init(_name: &'static CStr, module: &'static ThisModule) -> Result<Self> {
+ let mut reg = Pin::from(Box::try_new(Registration::new())?);
+ reg.as_mut().register::<T>(module)?;
+ Ok(Self {
+ _fs: reg,
+ _p: PhantomData,
+ })
+ }
+}
+
+/// Declares a kernel module that exposes a single file system.
+///
+/// The `type` argument must be a type which implements the [`Type`] trait. Also accepts various
+/// forms of kernel metadata.
+///
+/// # Examples
+///
+/// ```ignore
+/// use kernel::prelude::*;
+/// use kernel::{c_str, fs};
+///
+/// module_fs! {
+/// type: MyFs,
+/// name: b"my_fs_kernel_module",
+/// author: b"Rust for Linux Contributors",
+/// description: b"My very own file system kernel module!",
+/// license: b"GPL",
+/// }
+///
+/// struct MyFs;
+///
+/// #[vtable]
+/// impl fs::Context<Self> for MyFs {
+/// type Data = ();
+/// fn try_new() -> Result {
+/// Ok(())
+/// }
+/// }
+///
+/// impl fs::Type for MyFs {
+/// type Context = Self;
+/// const SUPER_TYPE: fs::Super = fs::Super::Independent;
+/// const NAME: &'static CStr = c_str!("example");
+/// const FLAGS: i32 = 0;
+///
+/// fn fill_super(_data: (), sb: fs::NewSuperBlock<'_, Self>) -> Result<&fs::SuperBlock<Self>> {
+/// let sb = sb.init(
+/// (),
+/// &fs::SuperParams {
+/// magic: 0x6578616d,
+/// ..fs::SuperParams::DEFAULT
+/// },
+/// )?;
+/// let sb = sb.init_root()?;
+/// Ok(sb)
+/// }
+/// }
+/// ```
+#[macro_export]
+macro_rules! module_fs {
+ (type: $type:ty, $($f:tt)*) => {
+ type ModuleType = $crate::fs::Module<$type>;
+ $crate::macros::module! {
+ type: ModuleType,
+ $($f)*
+ }
+ }
+}
diff --git a/rust/kernel/fs/param.rs b/rust/kernel/fs/param.rs
new file mode 100644
index 000000000000..445cea404bcd
--- /dev/null
+++ b/rust/kernel/fs/param.rs
@@ -0,0 +1,553 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! File system parameters and parsing them.
+//!
+//! C headers: [`include/linux/fs_parser.h`](../../../../../include/linux/fs_parser.h)
+
+use crate::{bindings, file, fs, str::CStr, Result};
+use core::{marker::PhantomData, ptr};
+
+/// The value of a file system parameter.
+pub enum Value<'a> {
+ /// The value is undefined.
+ Undefined,
+
+ /// There is no value, but parameter itself is a flag.
+ Flag,
+
+ /// The value is the given string.
+ String(&'a CStr),
+
+ /// The value is the given binary blob.
+ Blob(&'a mut [u8]),
+
+ /// The value is the given file.
+ File(&'a file::File),
+
+ /// The value is the given filename and the given directory file descriptor (which may be
+ /// `AT_FDCWD`, to indicate the current directory).
+ Filename(&'a fs::Filename, i32),
+}
+
+impl<'a> Value<'a> {
+ pub(super) fn from_fs_parameter(p: &'a bindings::fs_parameter) -> Self {
+ match p.type_() {
+ bindings::fs_value_type_fs_value_is_string => {
+ // SAFETY: `type_` is string, so it is ok to use the union field. Additionally, it
+ // is guaranteed to be valid while `p` is valid.
+ Self::String(unsafe { CStr::from_char_ptr(p.__bindgen_anon_1.string) })
+ }
+ bindings::fs_value_type_fs_value_is_flag => Self::Flag,
+ bindings::fs_value_type_fs_value_is_blob => {
+ // SAFETY: `type_` is blob, so it is ok to use the union field and size.
+ // Additionally, it is guaranteed to be valid while `p` is valid.
+ let slice = unsafe {
+ &mut *ptr::slice_from_raw_parts_mut(p.__bindgen_anon_1.blob.cast(), p.size)
+ };
+ Self::Blob(slice)
+ }
+ bindings::fs_value_type_fs_value_is_file => {
+ // SAFETY: `type_` is file, so it is ok to use the union field. Additionally, it is
+ // guaranteed to be valid while `p` is valid.
+ let file_ptr = unsafe { p.__bindgen_anon_1.file };
+ if file_ptr.is_null() {
+ Self::Undefined
+ } else {
+ // SAFETY: `file_ptr` is non-null and guaranteed to be valid while `p` is.
+ Self::File(unsafe { file::File::from_ptr(file_ptr) })
+ }
+ }
+ bindings::fs_value_type_fs_value_is_filename => {
+ // SAFETY: `type_` is filename, so it is ok to use the union field. Additionally,
+ // it is guaranteed to be valid while `p` is valid.
+ let filename_ptr = unsafe { p.__bindgen_anon_1.name };
+ if filename_ptr.is_null() {
+ Self::Undefined
+ } else {
+ // SAFETY: `filename_ptr` is non-null and guaranteed to be valid while `p` is.
+ Self::Filename(unsafe { fs::Filename::from_ptr(filename_ptr) }, p.dirfd)
+ }
+ }
+ _ => Self::Undefined,
+ }
+ }
+}
+
+/// A specification of a file system parameter.
+pub struct Spec {
+ name: &'static CStr,
+ flags: u16,
+ type_: bindings::fs_param_type,
+ extra: *const core::ffi::c_void,
+}
+
+const DEFAULT: Spec = Spec {
+ name: crate::c_str!(""),
+ flags: 0,
+ type_: None,
+ extra: core::ptr::null(),
+};
+
+macro_rules! define_param_type {
+ ($name:ident, $fntype:ty, $spec:expr, |$param:ident, $result:ident| $value:expr) => {
+ /// Module to support `$name` parameter types.
+ pub mod $name {
+ use super::*;
+
+ #[doc(hidden)]
+ pub const fn spec(name: &'static CStr) -> Spec {
+ const GIVEN: Spec = $spec;
+ Spec { name, ..GIVEN }
+ }
+
+ #[doc(hidden)]
+ pub const fn handler<S>(setfn: fn(&mut S, $fntype) -> Result) -> impl Handler<S> {
+ let c =
+ move |s: &mut S,
+ $param: &bindings::fs_parameter,
+ $result: &bindings::fs_parse_result| { setfn(s, $value) };
+ ConcreteHandler {
+ setfn: c,
+ _p: PhantomData,
+ }
+ }
+ }
+ };
+}
+
+// SAFETY: This is only called when the parse result is a boolean, so it is ok to access to union
+// field.
+define_param_type!(flag, bool, Spec { ..DEFAULT }, |_p, r| unsafe {
+ r.__bindgen_anon_1.boolean
+});
+
+define_param_type!(
+ flag_no,
+ bool,
+ Spec {
+ flags: bindings::fs_param_neg_with_no as _,
+ ..DEFAULT
+ },
+ // SAFETY: This is only called when the parse result is a boolean, so it is ok to access to
+ // union field.
+ |_p, r| unsafe { r.__bindgen_anon_1.boolean }
+);
+
+define_param_type!(
+ bool,
+ bool,
+ Spec {
+ type_: Some(bindings::fs_param_is_bool),
+ ..DEFAULT
+ },
+ // SAFETY: This is only called when the parse result is a boolean, so it is ok to access to
+ // union field.
+ |_p, r| unsafe { r.__bindgen_anon_1.boolean }
+);
+
+define_param_type!(
+ u32,
+ u32,
+ Spec {
+ type_: Some(bindings::fs_param_is_u32),
+ ..DEFAULT
+ },
+ // SAFETY: This is only called when the parse result is a u32, so it is ok to access to union
+ // field.
+ |_p, r| unsafe { r.__bindgen_anon_1.uint_32 }
+);
+
+define_param_type!(
+ u32oct,
+ u32,
+ Spec {
+ type_: Some(bindings::fs_param_is_u32),
+ extra: 8 as _,
+ ..DEFAULT
+ },
+ // SAFETY: This is only called when the parse result is a u32, so it is ok to access to union
+ // field.
+ |_p, r| unsafe { r.__bindgen_anon_1.uint_32 }
+);
+
+define_param_type!(
+ u32hex,
+ u32,
+ Spec {
+ type_: Some(bindings::fs_param_is_u32),
+ extra: 16 as _,
+ ..DEFAULT
+ },
+ // SAFETY: This is only called when the parse result is a u32, so it is ok to access to union
+ // field.
+ |_p, r| unsafe { r.__bindgen_anon_1.uint_32 }
+);
+
+define_param_type!(
+ s32,
+ i32,
+ Spec {
+ type_: Some(bindings::fs_param_is_s32),
+ ..DEFAULT
+ },
+ // SAFETY: This is only called when the parse result is an i32, so it is ok to access to union
+ // field.
+ |_p, r| unsafe { r.__bindgen_anon_1.int_32 }
+);
+
+define_param_type!(
+ u64,
+ u64,
+ Spec {
+ type_: Some(bindings::fs_param_is_u64),
+ extra: 16 as _,
+ ..DEFAULT
+ },
+ // SAFETY: This is only called when the parse result is a u32, so it is ok to access to union
+ // field.
+ |_p, r| unsafe { r.__bindgen_anon_1.uint_64 }
+);
+
+define_param_type!(
+ string,
+ &CStr,
+ Spec {
+ type_: Some(bindings::fs_param_is_string),
+ ..DEFAULT
+ },
+ // SAFETY: This is only called when the parse result is a string, so it is ok to access to
+ // union field.
+ |p, _r| unsafe { CStr::from_char_ptr(p.__bindgen_anon_1.string) }
+);
+
+/// Module to support `enum` parameter types.
+pub mod enum_ {
+ use super::*;
+
+ #[doc(hidden)]
+ pub const fn spec(name: &'static CStr, options: ConstantTable<'static>) -> Spec {
+ Spec {
+ name,
+ type_: Some(bindings::fs_param_is_enum),
+ extra: options.first as *const _ as _,
+ ..DEFAULT
+ }
+ }
+
+ #[doc(hidden)]
+ pub const fn handler<S>(setfn: fn(&mut S, u32) -> Result) -> impl Handler<S> {
+ let c = move |s: &mut S, _p: &bindings::fs_parameter, r: &bindings::fs_parse_result| {
+ // SAFETY: This is only called when the parse result is an enum, so it is ok to access
+ // to union field.
+ setfn(s, unsafe { r.__bindgen_anon_1.uint_32 })
+ };
+ ConcreteHandler {
+ setfn: c,
+ _p: PhantomData,
+ }
+ }
+}
+
+const ZERO_SPEC: bindings::fs_parameter_spec = bindings::fs_parameter_spec {
+ name: core::ptr::null(),
+ type_: None,
+ opt: 0,
+ flags: 0,
+ data: core::ptr::null(),
+};
+
+/// A zero-terminated parameter spec array, followed by handlers.
+#[repr(C)]
+pub struct SpecArray<const N: usize, S: 'static> {
+ specs: [bindings::fs_parameter_spec; N],
+ sentinel: bindings::fs_parameter_spec,
+ handlers: [&'static dyn Handler<S>; N],
+}
+
+impl<const N: usize, S: 'static> SpecArray<N, S> {
+ /// Creates a new spec array.
+ ///
+ /// Users are encouraged to use the [`define_fs_params`] macro to define the
+ /// [`super::Context::PARAMS`] constant.
+ ///
+ /// # Safety
+ ///
+ /// The type of the elements in `handlers` must be compatible with the types in specs. For
+ /// example, if `specs` declares that the i-th element is a bool then the i-th handler
+ /// should be for a bool.
+ pub const unsafe fn new(specs: [Spec; N], handlers: [&'static dyn Handler<S>; N]) -> Self {
+ let mut array = Self {
+ specs: [ZERO_SPEC; N],
+ sentinel: ZERO_SPEC,
+ handlers,
+ };
+ let mut i = 0usize;
+ while i < N {
+ array.specs[i] = bindings::fs_parameter_spec {
+ name: specs[i].name.as_char_ptr(),
+ type_: specs[i].type_,
+ opt: i as _,
+ flags: specs[i].flags,
+ data: specs[i].extra,
+ };
+ i += 1;
+ }
+ array
+ }
+
+ /// Returns a [`SpecTable`] backed by `self`.
+ ///
+ /// This is used to essentially erase the array size.
+ pub const fn as_table(&self) -> SpecTable<'_, S> {
+ SpecTable {
+ first: &self.specs[0],
+ handlers: &self.handlers,
+ _p: PhantomData,
+ }
+ }
+}
+
+/// A parameter spec table.
+///
+/// The table is guaranteed to be zero-terminated.
+///
+/// Users are encouraged to use the [`define_fs_params`] macro to define the
+/// [`super::Context::PARAMS`] constant.
+pub struct SpecTable<'a, S: 'static> {
+ pub(super) first: &'a bindings::fs_parameter_spec,
+ pub(super) handlers: &'a [&'static dyn Handler<S>],
+ _p: PhantomData<S>,
+}
+
+impl<S> SpecTable<'static, S> {
+ pub(super) const fn empty() -> Self {
+ Self {
+ first: &ZERO_SPEC,
+ handlers: &[],
+ _p: PhantomData,
+ }
+ }
+}
+
+/// A zero-terminated parameter constant array.
+#[repr(C)]
+pub struct ConstantArray<const N: usize> {
+ consts: [bindings::constant_table; N],
+ sentinel: bindings::constant_table,
+}
+
+impl<const N: usize> ConstantArray<N> {
+ /// Creates a new constant array.
+ ///
+ /// Users are encouraged to use the [`define_fs_params`] macro to define the
+ /// [`super::Context::PARAMS`] constant.
+ pub const fn new(consts: [(&'static CStr, u32); N]) -> Self {
+ const ZERO: bindings::constant_table = bindings::constant_table {
+ name: core::ptr::null(),
+ value: 0,
+ };
+ let mut array = Self {
+ consts: [ZERO; N],
+ sentinel: ZERO,
+ };
+ let mut i = 0usize;
+ while i < N {
+ array.consts[i] = bindings::constant_table {
+ name: consts[i].0.as_char_ptr(),
+ value: consts[i].1 as _,
+ };
+ i += 1;
+ }
+ array
+ }
+
+ /// Returns a [`ConstantTable`] backed by `self`.
+ ///
+ /// This is used to essentially erase the array size.
+ pub const fn as_table(&self) -> ConstantTable<'_> {
+ ConstantTable {
+ first: &self.consts[0],
+ }
+ }
+}
+
+/// A parameter constant table.
+///
+/// The table is guaranteed to be zero-terminated.
+pub struct ConstantTable<'a> {
+ pub(super) first: &'a bindings::constant_table,
+}
+
+#[doc(hidden)]
+pub trait Handler<S> {
+ fn handle_param(
+ &self,
+ state: &mut S,
+ p: &bindings::fs_parameter,
+ r: &bindings::fs_parse_result,
+ ) -> Result;
+}
+
+struct ConcreteHandler<
+ S,
+ T: Fn(&mut S, &bindings::fs_parameter, &bindings::fs_parse_result) -> Result,
+> {
+ setfn: T,
+ _p: PhantomData<S>,
+}
+
+impl<S, T: Fn(&mut S, &bindings::fs_parameter, &bindings::fs_parse_result) -> Result> Handler<S>
+ for ConcreteHandler<S, T>
+{
+ fn handle_param(
+ &self,
+ state: &mut S,
+ p: &bindings::fs_parameter,
+ r: &bindings::fs_parse_result,
+ ) -> Result {
+ (self.setfn)(state, p, r)
+ }
+}
+
+/// Counts the number of comma-separated entries surrounded by braces.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::count_brace_items;
+///
+/// assert_eq!(0, count_brace_items!());
+/// assert_eq!(1, count_brace_items!({ A }));
+/// assert_eq!(1, count_brace_items!({ A },));
+/// assert_eq!(2, count_brace_items!({ A }, { B }));
+/// assert_eq!(2, count_brace_items!({ A }, { B },));
+/// assert_eq!(3, count_brace_items!({ A }, { B }, { C }));
+/// assert_eq!(3, count_brace_items!({ A }, { B }, { C },));
+/// ```
+#[macro_export]
+macro_rules! count_brace_items {
+ ({$($item:tt)*}, $($remaining:tt)*) => { 1 + $crate::count_brace_items!($($remaining)*) };
+ ({$($item:tt)*}) => { 1 };
+ () => { 0 };
+}
+
+/// Defines the file system parameters of a given file system context.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::prelude::*;
+/// # use kernel::{c_str, fs, str::CString};
+///
+/// #[derive(Default)]
+/// struct State {
+/// flag: Option<bool>,
+/// flag_no: Option<bool>,
+/// bool_value: Option<bool>,
+/// u32_value: Option<u32>,
+/// i32_value: Option<i32>,
+/// u64_value: Option<u64>,
+/// str_value: Option<CString>,
+/// enum_value: Option<u32>,
+/// }
+///
+/// fn set_u32(s: &mut Box<State>, v: u32) -> Result {
+/// s.u32_value = Some(v);
+/// Ok(())
+/// }
+///
+/// struct Example;
+///
+/// #[vtable]
+/// impl fs::Context<Self> for Example {
+/// type Data = Box<State>;
+///
+/// kernel::define_fs_params! {Box<State>,
+/// {flag, "flag", |s, v| { s.flag = Some(v); Ok(()) } },
+/// {flag_no, "flagno", |s, v| { s.flag_no = Some(v); Ok(()) } },
+/// {bool, "bool", |s, v| { s.bool_value = Some(v); Ok(()) } },
+/// {u32, "u32", set_u32 },
+/// {u32oct, "u32oct", set_u32 },
+/// {u32hex, "u32hex", set_u32 },
+/// {s32, "s32", |s, v| { s.i32_value = Some(v); Ok(()) } },
+/// {u64, "u64", |s, v| { s.u64_value = Some(v); Ok(()) } },
+/// {string, "string", |s, v| {
+/// s.str_value = Some(CString::try_from_fmt(fmt!("{v}"))?);
+/// Ok(())
+/// }},
+/// {enum, "enum", [("first", 10), ("second", 20)], |s, v| {
+/// s.enum_value = Some(v);
+/// Ok(())
+/// }},
+/// }
+///
+/// fn try_new() -> Result<Self::Data> {
+/// Ok(Box::try_new(State::default())?)
+/// }
+/// }
+///
+/// # impl fs::Type for Example {
+/// # type Context = Self;
+/// # const SUPER_TYPE: fs::Super = fs::Super::Independent;
+/// # const NAME: &'static CStr = c_str!("example");
+/// # const FLAGS: i32 = 0;
+/// #
+/// # fn fill_super<'a>(
+/// # _data: Box<State>,
+/// # sb: fs::NewSuperBlock<'_, Self>,
+/// # ) -> Result<&fs::SuperBlock<Self>> {
+/// # let sb = sb.init(
+/// # (),
+/// # &fs::SuperParams {
+/// # magic: 0x6578616d,
+/// # ..fs::SuperParams::DEFAULT
+/// # },
+/// # )?;
+/// # let sb = sb.init_root()?;
+/// # Ok(sb)
+/// # }
+/// # }
+/// ```
+#[macro_export]
+macro_rules! define_fs_params {
+ ($data_type:ty, $({$($t:tt)*}),+ $(,)?) => {
+ const PARAMS: $crate::fs::param::SpecTable<'static, $data_type> =
+ {
+ use $crate::fs::param::{self, ConstantArray, Spec, SpecArray, Handler};
+ use $crate::c_str;
+ const COUNT: usize = $crate::count_brace_items!($({$($t)*},)*);
+ const SPECS: [Spec; COUNT] = $crate::define_fs_params!(@specs $({$($t)*},)*);
+ const HANDLERS: [&dyn Handler<$data_type>; COUNT] =
+ $crate::define_fs_params!(@handlers $data_type, $({$($t)*},)*);
+ // SAFETY: We defined matching specs and handlers above.
+ const ARRAY: SpecArray<COUNT, $data_type> =
+ unsafe { SpecArray::new(SPECS, HANDLERS) };
+ ARRAY.as_table()
+ };
+ };
+
+ (@handlers $data_type:ty, $({$($t:tt)*},)*) => {
+ [ $($crate::define_fs_params!(@handler $data_type, $($t)*),)* ]
+ };
+ (@handler $data_type:ty, enum, $name:expr, $opts:expr, $closure:expr) => {
+ &param::enum_::handler::<$data_type>($closure)
+ };
+ (@handler $data_type:ty, $type:ident, $name:expr, $closure:expr) => {
+ &param::$type::handler::<$data_type>($closure)
+ };
+
+ (@specs $({$($t:tt)*},)*) => {[ $($crate::define_fs_params!(@spec $($t)*),)* ]};
+ (@spec enum, $name:expr, [$($opts:tt)*], $closure:expr) => {
+ {
+ const COUNT: usize = $crate::count_paren_items!($($opts)*);
+ const OPTIONS: ConstantArray<COUNT> =
+ ConstantArray::new($crate::define_fs_params!(@c_str_first $($opts)*));
+ param::enum_::spec(c_str!($name), OPTIONS.as_table())
+ }
+ };
+ (@spec $type:ident, $name:expr, $closure:expr) => { param::$type::spec(c_str!($name)) };
+
+ (@c_str_first $(($first:expr, $second:expr)),+ $(,)?) => {
+ [$((c_str!($first), $second),)*]
+ };
+}
diff --git a/rust/kernel/gpio.rs b/rust/kernel/gpio.rs
new file mode 100644
index 000000000000..53c7b398d10b
--- /dev/null
+++ b/rust/kernel/gpio.rs
@@ -0,0 +1,505 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Support for gpio device drivers.
+//!
+//! C header: [`include/linux/gpio/driver.h`](../../../../include/linux/gpio/driver.h)
+
+use crate::{
+ bindings, device, error::code::*, error::from_kernel_result, sync::LockClassKey,
+ types::PointerWrapper, Error, Result,
+};
+use core::{
+ cell::UnsafeCell,
+ marker::{PhantomData, PhantomPinned},
+ pin::Pin,
+};
+use macros::vtable;
+
+#[cfg(CONFIG_GPIOLIB_IRQCHIP)]
+pub use irqchip::{ChipWithIrqChip, RegistrationWithIrqChip};
+
+/// The direction of a gpio line.
+pub enum LineDirection {
+ /// Direction is input.
+ In = bindings::GPIO_LINE_DIRECTION_IN as _,
+
+ /// Direction is output.
+ Out = bindings::GPIO_LINE_DIRECTION_OUT as _,
+}
+
+/// A gpio chip.
+#[vtable]
+pub trait Chip {
+ /// Context data associated with the gpio chip.
+ ///
+ /// It determines the type of the context data passed to each of the methods of the trait.
+ type Data: PointerWrapper + Sync + Send;
+
+ /// Returns the direction of the given gpio line.
+ fn get_direction(
+ _data: <Self::Data as PointerWrapper>::Borrowed<'_>,
+ _offset: u32,
+ ) -> Result<LineDirection> {
+ Err(ENOTSUPP)
+ }
+
+ /// Configures the direction as input of the given gpio line.
+ fn direction_input(
+ _data: <Self::Data as PointerWrapper>::Borrowed<'_>,
+ _offset: u32,
+ ) -> Result {
+ Err(EIO)
+ }
+
+ /// Configures the direction as output of the given gpio line.
+ ///
+ /// The value that will be initially output is also specified.
+ fn direction_output(
+ _data: <Self::Data as PointerWrapper>::Borrowed<'_>,
+ _offset: u32,
+ _value: bool,
+ ) -> Result {
+ Err(ENOTSUPP)
+ }
+
+ /// Returns the current value of the given gpio line.
+ fn get(_data: <Self::Data as PointerWrapper>::Borrowed<'_>, _offset: u32) -> Result<bool> {
+ Err(EIO)
+ }
+
+ /// Sets the value of the given gpio line.
+ fn set(_data: <Self::Data as PointerWrapper>::Borrowed<'_>, _offset: u32, _value: bool) {}
+}
+
+/// A registration of a gpio chip.
+///
+/// # Examples
+///
+/// The following example registers an empty gpio chip.
+///
+/// ```
+/// # use kernel::prelude::*;
+/// use kernel::{
+/// device::RawDevice,
+/// gpio::{self, Registration},
+/// };
+///
+/// struct MyGpioChip;
+/// #[vtable]
+/// impl gpio::Chip for MyGpioChip {
+/// type Data = ();
+/// }
+///
+/// fn example(parent: &dyn RawDevice) -> Result<Pin<Box<Registration<MyGpioChip>>>> {
+/// let mut r = Pin::from(Box::try_new(Registration::new())?);
+/// kernel::gpio_chip_register!(r.as_mut(), 32, None, parent, ())?;
+/// Ok(r)
+/// }
+/// ```
+pub struct Registration<T: Chip> {
+ gc: UnsafeCell<bindings::gpio_chip>,
+ parent: Option<device::Device>,
+ _p: PhantomData<T>,
+ _pin: PhantomPinned,
+}
+
+impl<T: Chip> Registration<T> {
+ /// Creates a new [`Registration`] but does not register it yet.
+ ///
+ /// It is allowed to move.
+ pub fn new() -> Self {
+ Self {
+ parent: None,
+ gc: UnsafeCell::new(bindings::gpio_chip::default()),
+ _pin: PhantomPinned,
+ _p: PhantomData,
+ }
+ }
+
+ /// Registers a gpio chip with the rest of the kernel.
+ ///
+ /// Users are encouraged to use the [`gpio_chip_register`] macro because it automatically
+ /// defines the lock classes and calls the registration function.
+ pub fn register(
+ self: Pin<&mut Self>,
+ gpio_count: u16,
+ base: Option<i32>,
+ parent: &dyn device::RawDevice,
+ data: T::Data,
+ lock_keys: [&'static LockClassKey; 2],
+ ) -> Result {
+ if self.parent.is_some() {
+ // Already registered.
+ return Err(EINVAL);
+ }
+
+ // SAFETY: We never move out of `this`.
+ let this = unsafe { self.get_unchecked_mut() };
+ {
+ let gc = this.gc.get_mut();
+
+ // Set up the callbacks.
+ gc.request = Some(bindings::gpiochip_generic_request);
+ gc.free = Some(bindings::gpiochip_generic_free);
+ if T::HAS_GET_DIRECTION {
+ gc.get_direction = Some(get_direction_callback::<T>);
+ }
+ if T::HAS_DIRECTION_INPUT {
+ gc.direction_input = Some(direction_input_callback::<T>);
+ }
+ if T::HAS_DIRECTION_OUTPUT {
+ gc.direction_output = Some(direction_output_callback::<T>);
+ }
+ if T::HAS_GET {
+ gc.get = Some(get_callback::<T>);
+ }
+ if T::HAS_SET {
+ gc.set = Some(set_callback::<T>);
+ }
+
+ // When a base is not explicitly given, use -1 for one to be picked.
+ if let Some(b) = base {
+ gc.base = b;
+ } else {
+ gc.base = -1;
+ }
+
+ gc.ngpio = gpio_count;
+ gc.parent = parent.raw_device();
+ gc.label = parent.name().as_char_ptr();
+
+ // TODO: Define `gc.owner` as well.
+ }
+
+ let data_pointer = <T::Data as PointerWrapper>::into_pointer(data);
+ // SAFETY: `gc` was initilised above, so it is valid.
+ let ret = unsafe {
+ bindings::gpiochip_add_data_with_key(
+ this.gc.get(),
+ data_pointer as _,
+ lock_keys[0].get(),
+ lock_keys[1].get(),
+ )
+ };
+ if ret < 0 {
+ // SAFETY: `data_pointer` was returned by `into_pointer` above.
+ unsafe { T::Data::from_pointer(data_pointer) };
+ return Err(Error::from_kernel_errno(ret));
+ }
+
+ this.parent = Some(device::Device::from_dev(parent));
+ Ok(())
+ }
+}
+
+// SAFETY: `Registration` doesn't offer any methods or access to fields when shared between threads
+// or CPUs, so it is safe to share it.
+unsafe impl<T: Chip> Sync for Registration<T> {}
+
+// SAFETY: Registration with and unregistration from the gpio subsystem can happen from any thread.
+// Additionally, `T::Data` (which is dropped during unregistration) is `Send`, so it is ok to move
+// `Registration` to different threads.
+#[allow(clippy::non_send_fields_in_send_ty)]
+unsafe impl<T: Chip> Send for Registration<T> {}
+
+impl<T: Chip> Default for Registration<T> {
+ fn default() -> Self {
+ Self::new()
+ }
+}
+
+impl<T: Chip> Drop for Registration<T> {
+ /// Removes the registration from the kernel if it has completed successfully before.
+ fn drop(&mut self) {
+ if self.parent.is_some() {
+ // Get a pointer to the data stored in chip before destroying it.
+ // SAFETY: `gc` was during registration, which is guaranteed to have succeeded (because
+ // `parent` is `Some(_)`, so it remains valid.
+ let data_pointer = unsafe { bindings::gpiochip_get_data(self.gc.get()) };
+
+ // SAFETY: By the same argument above, `gc` is still valid.
+ unsafe { bindings::gpiochip_remove(self.gc.get()) };
+
+ // Free data as well.
+ // SAFETY: `data_pointer` was returned by `into_pointer` during registration.
+ unsafe { <T::Data as PointerWrapper>::from_pointer(data_pointer) };
+ }
+ }
+}
+
+/// Registers a gpio chip with the rest of the kernel.
+///
+/// It automatically defines the required lock classes.
+#[macro_export]
+macro_rules! gpio_chip_register {
+ ($reg:expr, $count:expr, $base:expr, $parent:expr, $data:expr $(,)?) => {{
+ static CLASS1: $crate::sync::LockClassKey = $crate::sync::LockClassKey::new();
+ static CLASS2: $crate::sync::LockClassKey = $crate::sync::LockClassKey::new();
+ $crate::gpio::Registration::register(
+ $reg,
+ $count,
+ $base,
+ $parent,
+ $data,
+ [&CLASS1, &CLASS2],
+ )
+ }};
+}
+
+unsafe extern "C" fn get_direction_callback<T: Chip>(
+ gc: *mut bindings::gpio_chip,
+ offset: core::ffi::c_uint,
+) -> core::ffi::c_int {
+ from_kernel_result! {
+ // SAFETY: The value stored as chip data was returned by `into_pointer` during registration.
+ let data = unsafe { T::Data::borrow(bindings::gpiochip_get_data(gc)) };
+ Ok(T::get_direction(data, offset)? as i32)
+ }
+}
+
+unsafe extern "C" fn direction_input_callback<T: Chip>(
+ gc: *mut bindings::gpio_chip,
+ offset: core::ffi::c_uint,
+) -> core::ffi::c_int {
+ from_kernel_result! {
+ // SAFETY: The value stored as chip data was returned by `into_pointer` during registration.
+ let data = unsafe { T::Data::borrow(bindings::gpiochip_get_data(gc)) };
+ T::direction_input(data, offset)?;
+ Ok(0)
+ }
+}
+
+unsafe extern "C" fn direction_output_callback<T: Chip>(
+ gc: *mut bindings::gpio_chip,
+ offset: core::ffi::c_uint,
+ value: core::ffi::c_int,
+) -> core::ffi::c_int {
+ from_kernel_result! {
+ // SAFETY: The value stored as chip data was returned by `into_pointer` during registration.
+ let data = unsafe { T::Data::borrow(bindings::gpiochip_get_data(gc)) };
+ T::direction_output(data, offset, value != 0)?;
+ Ok(0)
+ }
+}
+
+unsafe extern "C" fn get_callback<T: Chip>(
+ gc: *mut bindings::gpio_chip,
+ offset: core::ffi::c_uint,
+) -> core::ffi::c_int {
+ from_kernel_result! {
+ // SAFETY: The value stored as chip data was returned by `into_pointer` during registration.
+ let data = unsafe { T::Data::borrow(bindings::gpiochip_get_data(gc)) };
+ let v = T::get(data, offset)?;
+ Ok(v as _)
+ }
+}
+
+unsafe extern "C" fn set_callback<T: Chip>(
+ gc: *mut bindings::gpio_chip,
+ offset: core::ffi::c_uint,
+ value: core::ffi::c_int,
+) {
+ // SAFETY: The value stored as chip data was returned by `into_pointer` during registration.
+ let data = unsafe { T::Data::borrow(bindings::gpiochip_get_data(gc)) };
+ T::set(data, offset, value != 0);
+}
+
+#[cfg(CONFIG_GPIOLIB_IRQCHIP)]
+mod irqchip {
+ use super::*;
+ use crate::irq;
+
+ /// A gpio chip that includes an irq chip.
+ pub trait ChipWithIrqChip: Chip {
+ /// Implements the irq flow for the gpio chip.
+ fn handle_irq_flow(
+ _data: <Self::Data as PointerWrapper>::Borrowed<'_>,
+ _desc: &irq::Descriptor,
+ _domain: &irq::Domain,
+ );
+ }
+
+ /// A registration of a gpio chip that includes an irq chip.
+ pub struct RegistrationWithIrqChip<T: ChipWithIrqChip> {
+ reg: Registration<T>,
+ irq_chip: UnsafeCell<bindings::irq_chip>,
+ parent_irq: u32,
+ }
+
+ impl<T: ChipWithIrqChip> RegistrationWithIrqChip<T> {
+ /// Creates a new [`RegistrationWithIrqChip`] but does not register it yet.
+ ///
+ /// It is allowed to move.
+ pub fn new() -> Self {
+ Self {
+ reg: Registration::new(),
+ irq_chip: UnsafeCell::new(bindings::irq_chip::default()),
+ parent_irq: 0,
+ }
+ }
+
+ /// Registers a gpio chip and its irq chip with the rest of the kernel.
+ ///
+ /// Users are encouraged to use the [`gpio_irq_chip_register`] macro because it
+ /// automatically defines the lock classes and calls the registration function.
+ pub fn register<U: irq::Chip<Data = T::Data>>(
+ mut self: Pin<&mut Self>,
+ gpio_count: u16,
+ base: Option<i32>,
+ parent: &dyn device::RawDevice,
+ data: T::Data,
+ parent_irq: u32,
+ lock_keys: [&'static LockClassKey; 2],
+ ) -> Result {
+ if self.reg.parent.is_some() {
+ // Already registered.
+ return Err(EINVAL);
+ }
+
+ // SAFETY: We never move out of `this`.
+ let this = unsafe { self.as_mut().get_unchecked_mut() };
+
+ // Initialise the irq_chip.
+ {
+ let irq_chip = this.irq_chip.get_mut();
+ irq_chip.name = parent.name().as_char_ptr();
+
+ // SAFETY: The gpio subsystem configures a pointer to `gpio_chip` as the irq chip
+ // data, so we use `IrqChipAdapter` to convert to the `T::Data`, which is the same
+ // as `irq::Chip::Data` per the bound above.
+ unsafe { irq::init_chip::<IrqChipAdapter>(irq_chip) };
+ }
+
+ // Initialise gc irq state.
+ {
+ let girq = &mut this.reg.gc.get_mut().irq;
+ girq.chip = this.irq_chip.get();
+ // SAFETY: By leaving `parent_handler_data` set to `null`, the gpio subsystem
+ // initialises it to a pointer to the gpio chip, which is what `FlowHandler<T>`
+ // expects.
+ girq.parent_handler = unsafe { irq::new_flow_handler::<FlowHandler<T>>() };
+ girq.num_parents = 1;
+ girq.parents = &mut this.parent_irq;
+ this.parent_irq = parent_irq;
+ girq.default_type = bindings::IRQ_TYPE_NONE;
+ girq.handler = Some(bindings::handle_bad_irq);
+ }
+
+ // SAFETY: `reg` is pinned when `self` is.
+ let pinned = unsafe { self.map_unchecked_mut(|r| &mut r.reg) };
+ pinned.register(gpio_count, base, parent, data, lock_keys)
+ }
+ }
+
+ impl<T: ChipWithIrqChip> Default for RegistrationWithIrqChip<T> {
+ fn default() -> Self {
+ Self::new()
+ }
+ }
+
+ // SAFETY: `RegistrationWithIrqChip` doesn't offer any methods or access to fields when shared
+ // between threads or CPUs, so it is safe to share it.
+ unsafe impl<T: ChipWithIrqChip> Sync for RegistrationWithIrqChip<T> {}
+
+ // SAFETY: Registration with and unregistration from the gpio subsystem (including irq chips for
+ // them) can happen from any thread. Additionally, `T::Data` (which is dropped during
+ // unregistration) is `Send`, so it is ok to move `Registration` to different threads.
+ #[allow(clippy::non_send_fields_in_send_ty)]
+ unsafe impl<T: ChipWithIrqChip> Send for RegistrationWithIrqChip<T> where T::Data: Send {}
+
+ struct FlowHandler<T: ChipWithIrqChip>(PhantomData<T>);
+
+ impl<T: ChipWithIrqChip> irq::FlowHandler for FlowHandler<T> {
+ type Data = *mut bindings::gpio_chip;
+
+ fn handle_irq_flow(gc: *mut bindings::gpio_chip, desc: &irq::Descriptor) {
+ // SAFETY: `FlowHandler` is only used in gpio chips, and it is removed when the gpio is
+ // unregistered, so we know that `gc` must still be valid. We also know that the value
+ // stored as gpio data was returned by `T::Data::into_pointer` again because
+ // `FlowHandler` is a private structure only used in this way.
+ let data = unsafe { T::Data::borrow(bindings::gpiochip_get_data(gc)) };
+
+ // SAFETY: `gc` is valid (see comment above), so we can dereference it.
+ let domain = unsafe { irq::Domain::from_ptr((*gc).irq.domain) };
+
+ T::handle_irq_flow(data, desc, &domain);
+ }
+ }
+
+ /// Adapter from an irq chip with `gpio_chip` pointer as context to one where the gpio chip
+ /// data is passed as context.
+ struct IrqChipAdapter<T: irq::Chip>(PhantomData<T>);
+
+ #[vtable]
+ impl<T: irq::Chip> irq::Chip for IrqChipAdapter<T> {
+ type Data = *mut bindings::gpio_chip;
+
+ const HAS_SET_TYPE: bool = T::HAS_SET_TYPE;
+ const HAS_SET_WAKE: bool = T::HAS_SET_WAKE;
+
+ fn ack(gc: *mut bindings::gpio_chip, irq_data: &irq::IrqData) {
+ // SAFETY: `IrqChipAdapter` is a private struct, only used when the data stored in the
+ // gpio chip is known to come from `T::Data`, and only valid while the gpio chip is
+ // registered, so `gc` is valid.
+ let data = unsafe { T::Data::borrow(bindings::gpiochip_get_data(gc as _)) };
+ T::ack(data, irq_data);
+ }
+
+ fn mask(gc: *mut bindings::gpio_chip, irq_data: &irq::IrqData) {
+ // SAFETY: `IrqChipAdapter` is a private struct, only used when the data stored in the
+ // gpio chip is known to come from `T::Data`, and only valid while the gpio chip is
+ // registered, so `gc` is valid.
+ let data = unsafe { T::Data::borrow(bindings::gpiochip_get_data(gc as _)) };
+ T::mask(data, irq_data);
+ }
+
+ fn unmask(gc: *mut bindings::gpio_chip, irq_data: &irq::IrqData) {
+ // SAFETY: `IrqChipAdapter` is a private struct, only used when the data stored in the
+ // gpio chip is known to come from `T::Data`, and only valid while the gpio chip is
+ // registered, so `gc` is valid.
+ let data = unsafe { T::Data::borrow(bindings::gpiochip_get_data(gc as _)) };
+ T::unmask(data, irq_data);
+ }
+
+ fn set_type(
+ gc: *mut bindings::gpio_chip,
+ irq_data: &mut irq::LockedIrqData,
+ flow_type: u32,
+ ) -> Result<irq::ExtraResult> {
+ // SAFETY: `IrqChipAdapter` is a private struct, only used when the data stored in the
+ // gpio chip is known to come from `T::Data`, and only valid while the gpio chip is
+ // registered, so `gc` is valid.
+ let data = unsafe { T::Data::borrow(bindings::gpiochip_get_data(gc as _)) };
+ T::set_type(data, irq_data, flow_type)
+ }
+
+ fn set_wake(gc: *mut bindings::gpio_chip, irq_data: &irq::IrqData, on: bool) -> Result {
+ // SAFETY: `IrqChipAdapter` is a private struct, only used when the data stored in the
+ // gpio chip is known to come from `T::Data`, and only valid while the gpio chip is
+ // registered, so `gc` is valid.
+ let data = unsafe { T::Data::borrow(bindings::gpiochip_get_data(gc as _)) };
+ T::set_wake(data, irq_data, on)
+ }
+ }
+
+ /// Registers a gpio chip and its irq chip with the rest of the kernel.
+ ///
+ /// It automatically defines the required lock classes.
+ #[macro_export]
+ macro_rules! gpio_irq_chip_register {
+ ($reg:expr, $irqchip:ty, $count:expr, $base:expr, $parent:expr, $data:expr,
+ $parent_irq:expr $(,)?) => {{
+ static CLASS1: $crate::sync::LockClassKey = $crate::sync::LockClassKey::new();
+ static CLASS2: $crate::sync::LockClassKey = $crate::sync::LockClassKey::new();
+ $crate::gpio::RegistrationWithIrqChip::register::<$irqchip>(
+ $reg,
+ $count,
+ $base,
+ $parent,
+ $data,
+ $parent_irq,
+ [&CLASS1, &CLASS2],
+ )
+ }};
+ }
+}
diff --git a/rust/kernel/hwrng.rs b/rust/kernel/hwrng.rs
new file mode 100644
index 000000000000..5918f567c332
--- /dev/null
+++ b/rust/kernel/hwrng.rs
@@ -0,0 +1,210 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Hardware Random Number Generator.
+//!
+//! C header: [`include/linux/hw_random.h`](../../../../include/linux/hw_random.h)
+
+use alloc::{boxed::Box, slice::from_raw_parts_mut};
+
+use crate::{
+ bindings, error::code::*, error::from_kernel_result, str::CString, to_result,
+ types::PointerWrapper, Result, ScopeGuard,
+};
+use macros::vtable;
+
+use core::{cell::UnsafeCell, fmt, marker::PhantomData, pin::Pin};
+
+/// This trait is implemented in order to provide callbacks to `struct hwrng`.
+#[vtable]
+pub trait Operations {
+ /// The pointer type that will be used to hold user-defined data type.
+ type Data: PointerWrapper + Send + Sync = ();
+
+ /// Initialization callback, can be left undefined.
+ fn init(_data: <Self::Data as PointerWrapper>::Borrowed<'_>) -> Result {
+ Err(EINVAL)
+ }
+
+ /// Cleanup callback, can be left undefined.
+ fn cleanup(_data: Self::Data) {}
+
+ /// Read data into the provided buffer.
+ /// Drivers can fill up to max bytes of data into the buffer.
+ /// The buffer is aligned for any type and its size is a multiple of 4 and >= 32 bytes.
+ fn read(
+ data: <Self::Data as PointerWrapper>::Borrowed<'_>,
+ buffer: &mut [u8],
+ wait: bool,
+ ) -> Result<u32>;
+}
+
+/// Registration structure for Hardware Random Number Generator driver.
+pub struct Registration<T: Operations> {
+ hwrng: UnsafeCell<bindings::hwrng>,
+ name: Option<CString>,
+ registered: bool,
+ _p: PhantomData<T>,
+}
+
+impl<T: Operations> Registration<T> {
+ /// Creates new instance of registration.
+ ///
+ /// The data must be registered.
+ pub fn new() -> Self {
+ Self {
+ hwrng: UnsafeCell::new(bindings::hwrng::default()),
+ name: None,
+ registered: false,
+ _p: PhantomData,
+ }
+ }
+
+ /// Returns a registered and pinned, heap-allocated representation of the registration.
+ pub fn new_pinned(
+ name: fmt::Arguments<'_>,
+ quality: u16,
+ data: T::Data,
+ ) -> Result<Pin<Box<Self>>> {
+ let mut reg = Pin::from(Box::try_new(Self::new())?);
+ reg.as_mut().register(name, quality, data)?;
+ Ok(reg)
+ }
+
+ /// Registers a hwrng device within the rest of the kernel.
+ ///
+ /// It must be pinned because the memory block that represents
+ /// the registration may be self-referential.
+ pub fn register(
+ self: Pin<&mut Self>,
+ name: fmt::Arguments<'_>,
+ quality: u16,
+ data: T::Data,
+ ) -> Result {
+ // SAFETY: We never move out of `this`.
+ let this = unsafe { self.get_unchecked_mut() };
+
+ if this.registered {
+ return Err(EINVAL);
+ }
+
+ let data_pointer = data.into_pointer();
+
+ // SAFETY: `data_pointer` comes from the call to `data.into_pointer()` above.
+ let guard = ScopeGuard::new(|| unsafe {
+ T::Data::from_pointer(data_pointer);
+ });
+
+ let name = CString::try_from_fmt(name)?;
+
+ // SAFETY: Registration is pinned and contains allocated and set to zero
+ // `bindings::hwrng` structure.
+ Self::init_hwrng(
+ unsafe { &mut *this.hwrng.get() },
+ &name,
+ quality,
+ data_pointer,
+ );
+
+ // SAFETY: `bindings::hwrng` is initialized above which guarantees safety.
+ to_result(unsafe { bindings::hwrng_register(this.hwrng.get()) })?;
+
+ this.registered = true;
+ this.name = Some(name);
+ guard.dismiss();
+ Ok(())
+ }
+
+ fn init_hwrng(
+ hwrng: &mut bindings::hwrng,
+ name: &CString,
+ quality: u16,
+ data: *const core::ffi::c_void,
+ ) {
+ hwrng.name = name.as_char_ptr();
+
+ hwrng.init = if T::HAS_INIT {
+ Some(Self::init_callback)
+ } else {
+ None
+ };
+ hwrng.cleanup = if T::HAS_CLEANUP {
+ Some(Self::cleanup_callback)
+ } else {
+ None
+ };
+ hwrng.data_present = None;
+ hwrng.data_read = None;
+ hwrng.read = Some(Self::read_callback);
+
+ hwrng.priv_ = data as _;
+ hwrng.quality = quality;
+
+ // SAFETY: All fields are properly initialized as
+ // remaining fields `list`, `ref` and `cleanup_done` are already
+ // zeroed by `bindings::hwrng::default()` call.
+ }
+
+ unsafe extern "C" fn init_callback(rng: *mut bindings::hwrng) -> core::ffi::c_int {
+ from_kernel_result! {
+ // SAFETY: `priv` private data field was initialized during creation of
+ // the `bindings::hwrng` in `Self::init_hwrng` method. This callback is only
+ // called once the driver is registered.
+ let data = unsafe { T::Data::borrow((*rng).priv_ as *const _) };
+ T::init(data)?;
+ Ok(0)
+ }
+ }
+
+ unsafe extern "C" fn cleanup_callback(rng: *mut bindings::hwrng) {
+ // SAFETY: `priv` private data field was initialized during creation of
+ // the `bindings::hwrng` in `Self::init_hwrng` method. This callback is only
+ // called once the driver is registered.
+ let data = unsafe { T::Data::from_pointer((*rng).priv_ as *const _) };
+ T::cleanup(data);
+ }
+
+ unsafe extern "C" fn read_callback(
+ rng: *mut bindings::hwrng,
+ data: *mut core::ffi::c_void,
+ max: usize,
+ wait: bindings::bool_,
+ ) -> core::ffi::c_int {
+ from_kernel_result! {
+ // SAFETY: `priv` private data field was initialized during creation of
+ // the `bindings::hwrng` in `Self::init_hwrng` method. This callback is only
+ // called once the driver is registered.
+ let drv_data = unsafe { T::Data::borrow((*rng).priv_ as *const _) };
+
+ // SAFETY: Slice is created from `data` and `max` arguments that are C's buffer
+ // along with its size in bytes that are safe for this conversion.
+ let buffer = unsafe { from_raw_parts_mut(data as *mut u8, max) };
+ let ret = T::read(drv_data, buffer, wait)?;
+ Ok(ret as _)
+ }
+ }
+}
+
+impl<T: Operations> Default for Registration<T> {
+ fn default() -> Self {
+ Self::new()
+ }
+}
+
+// SAFETY: `Registration` does not expose any of its state across threads.
+unsafe impl<T: Operations> Sync for Registration<T> {}
+
+// SAFETY: `Registration` is not restricted to a single thread,
+// its `T::Data` is also `Send` so it may be moved to different threads.
+#[allow(clippy::non_send_fields_in_send_ty)]
+unsafe impl<T: Operations> Send for Registration<T> {}
+
+impl<T: Operations> Drop for Registration<T> {
+ /// Removes the registration from the kernel if it has completed successfully before.
+ fn drop(&mut self) {
+ // SAFETY: The instance of Registration<T> is unregistered only
+ // after being initialized and registered before.
+ if self.registered {
+ unsafe { bindings::hwrng_unregister(self.hwrng.get()) };
+ }
+ }
+}
diff --git a/rust/kernel/io_buffer.rs b/rust/kernel/io_buffer.rs
new file mode 100644
index 000000000000..ccecc4763aca
--- /dev/null
+++ b/rust/kernel/io_buffer.rs
@@ -0,0 +1,153 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Buffers used in IO.
+
+use crate::Result;
+use alloc::vec::Vec;
+use core::mem::{size_of, MaybeUninit};
+
+/// Represents a buffer to be read from during IO.
+pub trait IoBufferReader {
+ /// Returns the number of bytes left to be read from the io buffer.
+ ///
+ /// Note that even reading less than this number of bytes may fail.
+ fn len(&self) -> usize;
+
+ /// Returns `true` if no data is available in the io buffer.
+ fn is_empty(&self) -> bool {
+ self.len() == 0
+ }
+
+ /// Reads raw data from the io buffer into a raw kernel buffer.
+ ///
+ /// # Safety
+ ///
+ /// The output buffer must be valid.
+ unsafe fn read_raw(&mut self, out: *mut u8, len: usize) -> Result;
+
+ /// Reads all data remaining in the io buffer.
+ ///
+ /// Returns `EFAULT` if the address does not currently point to mapped, readable memory.
+ fn read_all(&mut self) -> Result<Vec<u8>> {
+ let mut data = Vec::<u8>::new();
+ data.try_resize(self.len(), 0)?;
+
+ // SAFETY: The output buffer is valid as we just allocated it.
+ unsafe { self.read_raw(data.as_mut_ptr(), data.len())? };
+ Ok(data)
+ }
+
+ /// Reads a byte slice from the io buffer.
+ ///
+ /// Returns `EFAULT` if the byte slice is bigger than the remaining size of the user slice or
+ /// if the address does not currently point to mapped, readable memory.
+ fn read_slice(&mut self, data: &mut [u8]) -> Result {
+ // SAFETY: The output buffer is valid as it's coming from a live reference.
+ unsafe { self.read_raw(data.as_mut_ptr(), data.len()) }
+ }
+
+ /// Reads the contents of a plain old data (POD) type from the io buffer.
+ fn read<T: ReadableFromBytes>(&mut self) -> Result<T> {
+ let mut out = MaybeUninit::<T>::uninit();
+ // SAFETY: The buffer is valid as it was just allocated.
+ unsafe { self.read_raw(out.as_mut_ptr() as _, size_of::<T>()) }?;
+ // SAFETY: We just initialised the data.
+ Ok(unsafe { out.assume_init() })
+ }
+}
+
+/// Represents a buffer to be written to during IO.
+pub trait IoBufferWriter {
+ /// Returns the number of bytes left to be written into the io buffer.
+ ///
+ /// Note that even writing less than this number of bytes may fail.
+ fn len(&self) -> usize;
+
+ /// Returns `true` if the io buffer cannot hold any additional data.
+ fn is_empty(&self) -> bool {
+ self.len() == 0
+ }
+
+ /// Writes zeroes to the io buffer.
+ ///
+ /// Differently from the other write functions, `clear` will zero as much as it can and update
+ /// the writer internal state to reflect this. It will, however, return an error if it cannot
+ /// clear `len` bytes.
+ ///
+ /// For example, if a caller requests that 100 bytes be cleared but a segfault happens after
+ /// 20 bytes, then EFAULT is returned and the writer is advanced by 20 bytes.
+ fn clear(&mut self, len: usize) -> Result;
+
+ /// Writes a byte slice into the io buffer.
+ ///
+ /// Returns `EFAULT` if the byte slice is bigger than the remaining size of the io buffer or if
+ /// the address does not currently point to mapped, writable memory.
+ fn write_slice(&mut self, data: &[u8]) -> Result {
+ // SAFETY: The input buffer is valid as it's coming from a live reference.
+ unsafe { self.write_raw(data.as_ptr(), data.len()) }
+ }
+
+ /// Writes raw data to the io buffer from a raw kernel buffer.
+ ///
+ /// # Safety
+ ///
+ /// The input buffer must be valid.
+ unsafe fn write_raw(&mut self, data: *const u8, len: usize) -> Result;
+
+ /// Writes the contents of the given data into the io buffer.
+ fn write<T: WritableToBytes>(&mut self, data: &T) -> Result {
+ // SAFETY: The input buffer is valid as it's coming from a live
+ // reference to a type that implements `WritableToBytes`.
+ unsafe { self.write_raw(data as *const T as _, size_of::<T>()) }
+ }
+}
+
+/// Specifies that a type is safely readable from byte slices.
+///
+/// Not all types can be safely read from byte slices; examples from
+/// <https://doc.rust-lang.org/reference/behavior-considered-undefined.html> include `bool`
+/// that must be either `0` or `1`, and `char` that cannot be a surrogate or above `char::MAX`.
+///
+/// # Safety
+///
+/// Implementers must ensure that the type is made up only of types that can be safely read from
+/// arbitrary byte sequences (e.g., `u32`, `u64`, etc.).
+pub unsafe trait ReadableFromBytes {}
+
+// SAFETY: All bit patterns are acceptable values of the types below.
+unsafe impl ReadableFromBytes for u8 {}
+unsafe impl ReadableFromBytes for u16 {}
+unsafe impl ReadableFromBytes for u32 {}
+unsafe impl ReadableFromBytes for u64 {}
+unsafe impl ReadableFromBytes for usize {}
+unsafe impl ReadableFromBytes for i8 {}
+unsafe impl ReadableFromBytes for i16 {}
+unsafe impl ReadableFromBytes for i32 {}
+unsafe impl ReadableFromBytes for i64 {}
+unsafe impl ReadableFromBytes for isize {}
+
+/// Specifies that a type is safely writable to byte slices.
+///
+/// This means that we don't read undefined values (which leads to UB) in preparation for writing
+/// to the byte slice. It also ensures that no potentially sensitive information is leaked into the
+/// byte slices.
+///
+/// # Safety
+///
+/// A type must not include padding bytes and must be fully initialised to safely implement
+/// [`WritableToBytes`] (i.e., it doesn't contain [`MaybeUninit`] fields). A composition of
+/// writable types in a structure is not necessarily writable because it may result in padding
+/// bytes.
+pub unsafe trait WritableToBytes {}
+
+// SAFETY: Initialised instances of the following types have no uninitialised portions.
+unsafe impl WritableToBytes for u8 {}
+unsafe impl WritableToBytes for u16 {}
+unsafe impl WritableToBytes for u32 {}
+unsafe impl WritableToBytes for u64 {}
+unsafe impl WritableToBytes for usize {}
+unsafe impl WritableToBytes for i8 {}
+unsafe impl WritableToBytes for i16 {}
+unsafe impl WritableToBytes for i32 {}
+unsafe impl WritableToBytes for i64 {}
+unsafe impl WritableToBytes for isize {}
diff --git a/rust/kernel/io_mem.rs b/rust/kernel/io_mem.rs
new file mode 100644
index 000000000000..ff6886a9e3b7
--- /dev/null
+++ b/rust/kernel/io_mem.rs
@@ -0,0 +1,278 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Memory-mapped IO.
+//!
+//! C header: [`include/asm-generic/io.h`](../../../../include/asm-generic/io.h)
+
+#![allow(dead_code)]
+
+use crate::{bindings, error::code::*, Result};
+use core::convert::TryInto;
+
+/// Represents a memory resource.
+pub struct Resource {
+ offset: bindings::resource_size_t,
+ size: bindings::resource_size_t,
+}
+
+impl Resource {
+ pub(crate) fn new(
+ start: bindings::resource_size_t,
+ end: bindings::resource_size_t,
+ ) -> Option<Self> {
+ if start == 0 {
+ return None;
+ }
+ Some(Self {
+ offset: start,
+ size: end.checked_sub(start)?.checked_add(1)?,
+ })
+ }
+}
+
+/// Represents a memory block of at least `SIZE` bytes.
+///
+/// # Invariants
+///
+/// `ptr` is a non-null and valid address of at least `SIZE` bytes and returned by an `ioremap`
+/// variant. `ptr` is also 8-byte aligned.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::prelude::*;
+/// use kernel::io_mem::{IoMem, Resource};
+///
+/// fn test(res: Resource) -> Result {
+/// // Create an io mem block of at least 100 bytes.
+/// // SAFETY: No DMA operations are initiated through `mem`.
+/// let mem = unsafe { IoMem::<100>::try_new(res) }?;
+///
+/// // Read one byte from offset 10.
+/// let v = mem.readb(10);
+///
+/// // Write value to offset 20.
+/// mem.writeb(v, 20);
+///
+/// Ok(())
+/// }
+/// ```
+pub struct IoMem<const SIZE: usize> {
+ ptr: usize,
+}
+
+macro_rules! define_read {
+ ($(#[$attr:meta])* $name:ident, $try_name:ident, $type_name:ty) => {
+ /// Reads IO data from the given offset known, at compile time.
+ ///
+ /// If the offset is not known at compile time, the build will fail.
+ $(#[$attr])*
+ #[inline]
+ pub fn $name(&self, offset: usize) -> $type_name {
+ Self::check_offset::<$type_name>(offset);
+ let ptr = self.ptr.wrapping_add(offset);
+ // SAFETY: The type invariants guarantee that `ptr` is a valid pointer. The check above
+ // guarantees that the code won't build if `offset` makes the read go out of bounds
+ // (including the type size).
+ unsafe { bindings::$name(ptr as _) }
+ }
+
+ /// Reads IO data from the given offset.
+ ///
+ /// It fails if/when the offset (plus the type size) is out of bounds.
+ $(#[$attr])*
+ pub fn $try_name(&self, offset: usize) -> Result<$type_name> {
+ if !Self::offset_ok::<$type_name>(offset) {
+ return Err(EINVAL);
+ }
+ let ptr = self.ptr.wrapping_add(offset);
+ // SAFETY: The type invariants guarantee that `ptr` is a valid pointer. The check above
+ // returns an error if `offset` would make the read go out of bounds (including the
+ // type size).
+ Ok(unsafe { bindings::$name(ptr as _) })
+ }
+ };
+}
+
+macro_rules! define_write {
+ ($(#[$attr:meta])* $name:ident, $try_name:ident, $type_name:ty) => {
+ /// Writes IO data to the given offset, known at compile time.
+ ///
+ /// If the offset is not known at compile time, the build will fail.
+ $(#[$attr])*
+ #[inline]
+ pub fn $name(&self, value: $type_name, offset: usize) {
+ Self::check_offset::<$type_name>(offset);
+ let ptr = self.ptr.wrapping_add(offset);
+ // SAFETY: The type invariants guarantee that `ptr` is a valid pointer. The check above
+ // guarantees that the code won't link if `offset` makes the write go out of bounds
+ // (including the type size).
+ unsafe { bindings::$name(value, ptr as _) }
+ }
+
+ /// Writes IO data to the given offset.
+ ///
+ /// It fails if/when the offset (plus the type size) is out of bounds.
+ $(#[$attr])*
+ pub fn $try_name(&self, value: $type_name, offset: usize) -> Result {
+ if !Self::offset_ok::<$type_name>(offset) {
+ return Err(EINVAL);
+ }
+ let ptr = self.ptr.wrapping_add(offset);
+ // SAFETY: The type invariants guarantee that `ptr` is a valid pointer. The check above
+ // returns an error if `offset` would make the write go out of bounds (including the
+ // type size).
+ unsafe { bindings::$name(value, ptr as _) };
+ Ok(())
+ }
+ };
+}
+
+impl<const SIZE: usize> IoMem<SIZE> {
+ /// Tries to create a new instance of a memory block.
+ ///
+ /// The resource described by `res` is mapped into the CPU's address space so that it can be
+ /// accessed directly. It is also consumed by this function so that it can't be mapped again
+ /// to a different address.
+ ///
+ /// # Safety
+ ///
+ /// Callers must ensure that either (a) the resulting interface cannot be used to initiate DMA
+ /// operations, or (b) that DMA operations initiated via the returned interface use DMA handles
+ /// allocated through the `dma` module.
+ pub unsafe fn try_new(res: Resource) -> Result<Self> {
+ // Check that the resource has at least `SIZE` bytes in it.
+ if res.size < SIZE.try_into()? {
+ return Err(EINVAL);
+ }
+
+ // To be able to check pointers at compile time based only on offsets, we need to guarantee
+ // that the base pointer is minimally aligned. So we conservatively expect at least 8 bytes.
+ if res.offset % 8 != 0 {
+ crate::pr_err!("Physical address is not 64-bit aligned: {:x}", res.offset);
+ return Err(EDOM);
+ }
+
+ // Try to map the resource.
+ // SAFETY: Just mapping the memory range.
+ let addr = unsafe { bindings::ioremap(res.offset, res.size as _) };
+ if addr.is_null() {
+ Err(ENOMEM)
+ } else {
+ // INVARIANT: `addr` is non-null and was returned by `ioremap`, so it is valid. It is
+ // also 8-byte aligned because we checked it above.
+ Ok(Self { ptr: addr as usize })
+ }
+ }
+
+ #[inline]
+ const fn offset_ok<T>(offset: usize) -> bool {
+ let type_size = core::mem::size_of::<T>();
+ if let Some(end) = offset.checked_add(type_size) {
+ end <= SIZE && offset % type_size == 0
+ } else {
+ false
+ }
+ }
+
+ fn offset_ok_of_val<T: ?Sized>(offset: usize, value: &T) -> bool {
+ let value_size = core::mem::size_of_val(value);
+ let value_alignment = core::mem::align_of_val(value);
+ if let Some(end) = offset.checked_add(value_size) {
+ end <= SIZE && offset % value_alignment == 0
+ } else {
+ false
+ }
+ }
+
+ #[inline]
+ const fn check_offset<T>(offset: usize) {
+ crate::build_assert!(Self::offset_ok::<T>(offset), "IoMem offset overflow");
+ }
+
+ /// Copy memory block from an i/o memory by filling the specified buffer with it.
+ ///
+ /// # Examples
+ /// ```
+ /// use kernel::io_mem::{self, IoMem, Resource};
+ ///
+ /// fn test(res: Resource) -> Result {
+ /// // Create an i/o memory block of at least 100 bytes.
+ /// let mem = unsafe { IoMem::<100>::try_new(res) }?;
+ ///
+ /// let mut buffer: [u8; 32] = [0; 32];
+ ///
+ /// // Memcpy 16 bytes from an offset 10 of i/o memory block into the buffer.
+ /// mem.try_memcpy_fromio(&mut buffer[..16], 10)?;
+ ///
+ /// Ok(())
+ /// }
+ /// ```
+ pub fn try_memcpy_fromio(&self, buffer: &mut [u8], offset: usize) -> Result {
+ if !Self::offset_ok_of_val(offset, buffer) {
+ return Err(EINVAL);
+ }
+
+ let ptr = self.ptr.wrapping_add(offset);
+
+ // SAFETY:
+ // - The type invariants guarantee that `ptr` is a valid pointer.
+ // - The bounds of `buffer` are checked with a call to `offset_ok_of_val()`.
+ unsafe {
+ bindings::memcpy_fromio(
+ buffer.as_mut_ptr() as *mut _,
+ ptr as *const _,
+ buffer.len() as _,
+ )
+ };
+ Ok(())
+ }
+
+ define_read!(readb, try_readb, u8);
+ define_read!(readw, try_readw, u16);
+ define_read!(readl, try_readl, u32);
+ define_read!(
+ #[cfg(CONFIG_64BIT)]
+ readq,
+ try_readq,
+ u64
+ );
+
+ define_read!(readb_relaxed, try_readb_relaxed, u8);
+ define_read!(readw_relaxed, try_readw_relaxed, u16);
+ define_read!(readl_relaxed, try_readl_relaxed, u32);
+ define_read!(
+ #[cfg(CONFIG_64BIT)]
+ readq_relaxed,
+ try_readq_relaxed,
+ u64
+ );
+
+ define_write!(writeb, try_writeb, u8);
+ define_write!(writew, try_writew, u16);
+ define_write!(writel, try_writel, u32);
+ define_write!(
+ #[cfg(CONFIG_64BIT)]
+ writeq,
+ try_writeq,
+ u64
+ );
+
+ define_write!(writeb_relaxed, try_writeb_relaxed, u8);
+ define_write!(writew_relaxed, try_writew_relaxed, u16);
+ define_write!(writel_relaxed, try_writel_relaxed, u32);
+ define_write!(
+ #[cfg(CONFIG_64BIT)]
+ writeq_relaxed,
+ try_writeq_relaxed,
+ u64
+ );
+}
+
+impl<const SIZE: usize> Drop for IoMem<SIZE> {
+ fn drop(&mut self) {
+ // SAFETY: By the type invariant, `self.ptr` is a value returned by a previous successful
+ // call to `ioremap`.
+ unsafe { bindings::iounmap(self.ptr as _) };
+ }
+}
diff --git a/rust/kernel/iov_iter.rs b/rust/kernel/iov_iter.rs
new file mode 100644
index 000000000000..b9b8dc882bd0
--- /dev/null
+++ b/rust/kernel/iov_iter.rs
@@ -0,0 +1,81 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! IO vector iterators.
+//!
+//! C header: [`include/linux/uio.h`](../../../../include/linux/uio.h)
+
+use crate::{
+ bindings,
+ error::code::*,
+ io_buffer::{IoBufferReader, IoBufferWriter},
+ Result,
+};
+
+/// Wraps the kernel's `struct iov_iter`.
+///
+/// # Invariants
+///
+/// The pointer `IovIter::ptr` is non-null and valid.
+pub struct IovIter {
+ ptr: *mut bindings::iov_iter,
+}
+
+impl IovIter {
+ fn common_len(&self) -> usize {
+ // SAFETY: `IovIter::ptr` is guaranteed to be valid by the type invariants.
+ unsafe { (*self.ptr).count }
+ }
+
+ /// Constructs a new [`struct iov_iter`] wrapper.
+ ///
+ /// # Safety
+ ///
+ /// The pointer `ptr` must be non-null and valid for the lifetime of the object.
+ pub(crate) unsafe fn from_ptr(ptr: *mut bindings::iov_iter) -> Self {
+ // INVARIANTS: the safety contract ensures the type invariant will hold.
+ Self { ptr }
+ }
+}
+
+impl IoBufferWriter for IovIter {
+ fn len(&self) -> usize {
+ self.common_len()
+ }
+
+ fn clear(&mut self, mut len: usize) -> Result {
+ while len > 0 {
+ // SAFETY: `IovIter::ptr` is guaranteed to be valid by the type invariants.
+ let written = unsafe { bindings::iov_iter_zero(len, self.ptr) };
+ if written == 0 {
+ return Err(EFAULT);
+ }
+
+ len -= written;
+ }
+ Ok(())
+ }
+
+ unsafe fn write_raw(&mut self, data: *const u8, len: usize) -> Result {
+ let res = unsafe { bindings::copy_to_iter(data as _, len, self.ptr) };
+ if res != len {
+ Err(EFAULT)
+ } else {
+ Ok(())
+ }
+ }
+}
+
+impl IoBufferReader for IovIter {
+ fn len(&self) -> usize {
+ self.common_len()
+ }
+
+ unsafe fn read_raw(&mut self, out: *mut u8, len: usize) -> Result {
+ let res = unsafe { bindings::copy_from_iter(out as _, len, self.ptr) };
+ if res != len {
+ Err(EFAULT)
+ } else {
+ Ok(())
+ }
+ }
+}
diff --git a/rust/kernel/irq.rs b/rust/kernel/irq.rs
new file mode 100644
index 000000000000..f2fa270dd728
--- /dev/null
+++ b/rust/kernel/irq.rs
@@ -0,0 +1,681 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Interrupts and interrupt chips.
+//!
+//! See <https://www.kernel.org/doc/Documentation/core-api/genericirq.rst>.
+//!
+//! C headers: [`include/linux/irq.h`](../../../../include/linux/irq.h) and
+//! [`include/linux/interrupt.h`](../../../../include/linux/interrupt.h).
+
+#![allow(dead_code)]
+
+use crate::{
+ bindings,
+ error::{from_kernel_result, to_result},
+ str::CString,
+ types::PointerWrapper,
+ Error, Result, ScopeGuard,
+};
+use core::{fmt, marker::PhantomData, ops::Deref};
+use macros::vtable;
+
+/// The type of irq hardware numbers.
+pub type HwNumber = bindings::irq_hw_number_t;
+
+/// Wraps the kernel's `struct irq_data`.
+///
+/// # Invariants
+///
+/// The pointer `IrqData::ptr` is non-null and valid.
+pub struct IrqData {
+ ptr: *mut bindings::irq_data,
+}
+
+impl IrqData {
+ /// Creates a new `IrqData` instance from a raw pointer.
+ ///
+ /// # Safety
+ ///
+ /// Callers must ensure that `ptr` is non-null and valid when the function is called, and that
+ /// it remains valid for the lifetime of the return [`IrqData`] instance.
+ unsafe fn from_ptr(ptr: *mut bindings::irq_data) -> Self {
+ // INVARIANTS: By the safety requirements, the instance we're creating satisfies the type
+ // invariants.
+ Self { ptr }
+ }
+
+ /// Returns the hardware irq number.
+ pub fn hwirq(&self) -> HwNumber {
+ // SAFETY: By the type invariants, it's ok to dereference `ptr`.
+ unsafe { (*self.ptr).hwirq }
+ }
+}
+
+/// Wraps the kernel's `struct irq_data` when it is locked.
+///
+/// Being locked allows additional operations to be performed on the data.
+pub struct LockedIrqData(IrqData);
+
+impl LockedIrqData {
+ /// Sets the high-level irq flow handler to the builtin one for level-triggered irqs.
+ pub fn set_level_handler(&mut self) {
+ // SAFETY: By the type invariants of `self.0`, we know `self.0.ptr` is valid.
+ unsafe { bindings::irq_set_handler_locked(self.0.ptr, Some(bindings::handle_level_irq)) };
+ }
+
+ /// Sets the high-level irq flow handler to the builtin one for edge-triggered irqs.
+ pub fn set_edge_handler(&mut self) {
+ // SAFETY: By the type invariants of `self.0`, we know `self.0.ptr` is valid.
+ unsafe { bindings::irq_set_handler_locked(self.0.ptr, Some(bindings::handle_edge_irq)) };
+ }
+
+ /// Sets the high-level irq flow handler to the builtin one for bad irqs.
+ pub fn set_bad_handler(&mut self) {
+ // SAFETY: By the type invariants of `self.0`, we know `self.0.ptr` is valid.
+ unsafe { bindings::irq_set_handler_locked(self.0.ptr, Some(bindings::handle_bad_irq)) };
+ }
+}
+
+impl Deref for LockedIrqData {
+ type Target = IrqData;
+
+ fn deref(&self) -> &Self::Target {
+ &self.0
+ }
+}
+
+/// Extra information returned by some of the [`Chip`] methods on success.
+pub enum ExtraResult {
+ /// Indicates that the caller (irq core) will update the descriptor state.
+ None = bindings::IRQ_SET_MASK_OK as _,
+
+ /// Indicates that the callee (irq chip implementation) already updated the descriptor state.
+ NoCopy = bindings::IRQ_SET_MASK_OK_NOCOPY as _,
+
+ /// Same as [`ExtraResult::None`] in terms of updating descriptor state. It is used in stacked
+ /// irq chips to indicate that descendant chips should be skipped.
+ Done = bindings::IRQ_SET_MASK_OK_DONE as _,
+}
+
+/// An irq chip.
+///
+/// It is a trait for the functions defined in [`struct irq_chip`].
+///
+/// [`struct irq_chip`]: ../../../include/linux/irq.h
+#[vtable]
+pub trait Chip: Sized {
+ /// The type of the context data stored in the irq chip and made available on each callback.
+ type Data: PointerWrapper;
+
+ /// Called at the start of a new interrupt.
+ fn ack(data: <Self::Data as PointerWrapper>::Borrowed<'_>, irq_data: &IrqData);
+
+ /// Masks an interrupt source.
+ fn mask(data: <Self::Data as PointerWrapper>::Borrowed<'_>, irq_data: &IrqData);
+
+ /// Unmasks an interrupt source.
+ fn unmask(_data: <Self::Data as PointerWrapper>::Borrowed<'_>, irq_data: &IrqData);
+
+ /// Sets the flow type of an interrupt.
+ ///
+ /// The flow type is a combination of the constants in [`Type`].
+ fn set_type(
+ _data: <Self::Data as PointerWrapper>::Borrowed<'_>,
+ _irq_data: &mut LockedIrqData,
+ _flow_type: u32,
+ ) -> Result<ExtraResult> {
+ Ok(ExtraResult::None)
+ }
+
+ /// Enables or disables power-management wake-on of an interrupt.
+ fn set_wake(
+ _data: <Self::Data as PointerWrapper>::Borrowed<'_>,
+ _irq_data: &IrqData,
+ _on: bool,
+ ) -> Result {
+ Ok(())
+ }
+}
+
+/// Initialises `chip` with the callbacks defined in `T`.
+///
+/// # Safety
+///
+/// The caller must ensure that the value stored in the irq chip data is the result of calling
+/// [`PointerWrapper::into_pointer] for the [`T::Data`] type.
+pub(crate) unsafe fn init_chip<T: Chip>(chip: &mut bindings::irq_chip) {
+ chip.irq_ack = Some(irq_ack_callback::<T>);
+ chip.irq_mask = Some(irq_mask_callback::<T>);
+ chip.irq_unmask = Some(irq_unmask_callback::<T>);
+
+ if T::HAS_SET_TYPE {
+ chip.irq_set_type = Some(irq_set_type_callback::<T>);
+ }
+
+ if T::HAS_SET_WAKE {
+ chip.irq_set_wake = Some(irq_set_wake_callback::<T>);
+ }
+}
+
+/// Enables or disables power-management wake-on for the given irq number.
+pub fn set_wake(irq: u32, on: bool) -> Result {
+ // SAFETY: Just an FFI call, there are no extra requirements for safety.
+ let ret = unsafe { bindings::irq_set_irq_wake(irq, on as _) };
+ if ret < 0 {
+ Err(Error::from_kernel_errno(ret))
+ } else {
+ Ok(())
+ }
+}
+
+unsafe extern "C" fn irq_ack_callback<T: Chip>(irq_data: *mut bindings::irq_data) {
+ // SAFETY: The safety requirements of `init_chip`, which is the only place that uses this
+ // callback, ensure that the value stored as irq chip data comes from a previous call to
+ // `PointerWrapper::into_pointer`.
+ let data = unsafe { T::Data::borrow(bindings::irq_data_get_irq_chip_data(irq_data)) };
+
+ // SAFETY: The value returned by `IrqData` is only valid until the end of this function, and
+ // `irq_data` is guaranteed to be valid until then (by the contract with C code).
+ T::ack(data, unsafe { &IrqData::from_ptr(irq_data) })
+}
+
+unsafe extern "C" fn irq_mask_callback<T: Chip>(irq_data: *mut bindings::irq_data) {
+ // SAFETY: The safety requirements of `init_chip`, which is the only place that uses this
+ // callback, ensure that the value stored as irq chip data comes from a previous call to
+ // `PointerWrapper::into_pointer`.
+ let data = unsafe { T::Data::borrow(bindings::irq_data_get_irq_chip_data(irq_data)) };
+
+ // SAFETY: The value returned by `IrqData` is only valid until the end of this function, and
+ // `irq_data` is guaranteed to be valid until then (by the contract with C code).
+ T::mask(data, unsafe { &IrqData::from_ptr(irq_data) })
+}
+
+unsafe extern "C" fn irq_unmask_callback<T: Chip>(irq_data: *mut bindings::irq_data) {
+ // SAFETY: The safety requirements of `init_chip`, which is the only place that uses this
+ // callback, ensure that the value stored as irq chip data comes from a previous call to
+ // `PointerWrapper::into_pointer`.
+ let data = unsafe { T::Data::borrow(bindings::irq_data_get_irq_chip_data(irq_data)) };
+
+ // SAFETY: The value returned by `IrqData` is only valid until the end of this function, and
+ // `irq_data` is guaranteed to be valid until then (by the contract with C code).
+ T::unmask(data, unsafe { &IrqData::from_ptr(irq_data) })
+}
+
+unsafe extern "C" fn irq_set_type_callback<T: Chip>(
+ irq_data: *mut bindings::irq_data,
+ flow_type: core::ffi::c_uint,
+) -> core::ffi::c_int {
+ from_kernel_result! {
+ // SAFETY: The safety requirements of `init_chip`, which is the only place that uses this
+ // callback, ensure that the value stored as irq chip data comes from a previous call to
+ // `PointerWrapper::into_pointer`.
+ let data = unsafe { T::Data::borrow(bindings::irq_data_get_irq_chip_data(irq_data)) };
+
+ // SAFETY: The value returned by `IrqData` is only valid until the end of this function, and
+ // `irq_data` is guaranteed to be valid until then (by the contract with C code).
+ let ret = T::set_type(
+ data,
+ &mut LockedIrqData(unsafe { IrqData::from_ptr(irq_data) }),
+ flow_type,
+ )?;
+ Ok(ret as _)
+ }
+}
+
+unsafe extern "C" fn irq_set_wake_callback<T: Chip>(
+ irq_data: *mut bindings::irq_data,
+ on: core::ffi::c_uint,
+) -> core::ffi::c_int {
+ from_kernel_result! {
+ // SAFETY: The safety requirements of `init_chip`, which is the only place that uses this
+ // callback, ensure that the value stored as irq chip data comes from a previous call to
+ // `PointerWrapper::into_pointer`.
+ let data = unsafe { T::Data::borrow(bindings::irq_data_get_irq_chip_data(irq_data)) };
+
+ // SAFETY: The value returned by `IrqData` is only valid until the end of this function, and
+ // `irq_data` is guaranteed to be valid until then (by the contract with C code).
+ T::set_wake(data, unsafe { &IrqData::from_ptr(irq_data) }, on != 0)?;
+ Ok(0)
+ }
+}
+
+/// Contains constants that describes how an interrupt can be triggered.
+///
+/// It is tagged with `non_exhaustive` to prevent users from instantiating it.
+#[non_exhaustive]
+pub struct Type;
+
+impl Type {
+ /// The interrupt cannot be triggered.
+ pub const NONE: u32 = bindings::IRQ_TYPE_NONE;
+
+ /// The interrupt is triggered when the signal goes from low to high.
+ pub const EDGE_RISING: u32 = bindings::IRQ_TYPE_EDGE_RISING;
+
+ /// The interrupt is triggered when the signal goes from high to low.
+ pub const EDGE_FALLING: u32 = bindings::IRQ_TYPE_EDGE_FALLING;
+
+ /// The interrupt is triggered when the signal goes from low to high and when it goes to high
+ /// to low.
+ pub const EDGE_BOTH: u32 = bindings::IRQ_TYPE_EDGE_BOTH;
+
+ /// The interrupt is triggered while the signal is held high.
+ pub const LEVEL_HIGH: u32 = bindings::IRQ_TYPE_LEVEL_HIGH;
+
+ /// The interrupt is triggered while the signal is held low.
+ pub const LEVEL_LOW: u32 = bindings::IRQ_TYPE_LEVEL_LOW;
+}
+
+/// Wraps the kernel's `struct irq_desc`.
+///
+/// # Invariants
+///
+/// The pointer `Descriptor::ptr` is non-null and valid.
+pub struct Descriptor {
+ pub(crate) ptr: *mut bindings::irq_desc,
+}
+
+impl Descriptor {
+ /// Constructs a new `struct irq_desc` wrapper.
+ ///
+ /// # Safety
+ ///
+ /// The pointer `ptr` must be non-null and valid for the lifetime of the returned object.
+ unsafe fn from_ptr(ptr: *mut bindings::irq_desc) -> Self {
+ // INVARIANT: The safety requirements ensure the invariant.
+ Self { ptr }
+ }
+
+ /// Calls `chained_irq_enter` and returns a guard that calls `chained_irq_exit` once dropped.
+ ///
+ /// It is meant to be used by chained irq handlers to dispatch irqs to the next handlers.
+ pub fn enter_chained(&self) -> ChainedGuard<'_> {
+ // SAFETY: By the type invariants, `ptr` is always non-null and valid.
+ let irq_chip = unsafe { bindings::irq_desc_get_chip(self.ptr) };
+
+ // SAFETY: By the type invariants, `ptr` is always non-null and valid. `irq_chip` was just
+ // returned from `ptr`, so it is still valid too.
+ unsafe { bindings::chained_irq_enter(irq_chip, self.ptr) };
+ ChainedGuard {
+ desc: self,
+ irq_chip,
+ }
+ }
+}
+
+struct InternalRegistration<T: PointerWrapper> {
+ irq: u32,
+ data: *mut core::ffi::c_void,
+ name: CString,
+ _p: PhantomData<T>,
+}
+
+impl<T: PointerWrapper> InternalRegistration<T> {
+ /// Registers a new irq handler.
+ ///
+ /// # Safety
+ ///
+ /// Callers must ensure that `handler` and `thread_fn` are compatible with the registration,
+ /// that is, that they only use their second argument while the call is happening and that they
+ /// only call [`T::borrow`] on it (e.g., they shouldn't call [`T::from_pointer`] and consume
+ /// it).
+ unsafe fn try_new(
+ irq: core::ffi::c_uint,
+ handler: bindings::irq_handler_t,
+ thread_fn: bindings::irq_handler_t,
+ flags: usize,
+ data: T,
+ name: fmt::Arguments<'_>,
+ ) -> Result<Self> {
+ let ptr = data.into_pointer() as *mut _;
+ let name = CString::try_from_fmt(name)?;
+ let guard = ScopeGuard::new(|| {
+ // SAFETY: `ptr` came from a previous call to `into_pointer`.
+ unsafe { T::from_pointer(ptr) };
+ });
+ // SAFETY: `name` and `ptr` remain valid as long as the registration is alive.
+ to_result(unsafe {
+ bindings::request_threaded_irq(
+ irq,
+ handler,
+ thread_fn,
+ flags as _,
+ name.as_char_ptr(),
+ ptr,
+ )
+ })?;
+ guard.dismiss();
+ Ok(Self {
+ irq,
+ name,
+ data: ptr,
+ _p: PhantomData,
+ })
+ }
+}
+
+impl<T: PointerWrapper> Drop for InternalRegistration<T> {
+ fn drop(&mut self) {
+ // Unregister irq handler.
+ //
+ // SAFETY: When `try_new` succeeds, the irq was successfully requested, so it is ok to free
+ // it here.
+ unsafe { bindings::free_irq(self.irq, self.data) };
+
+ // Free context data.
+ //
+ // SAFETY: This matches the call to `into_pointer` from `try_new` in the success case.
+ unsafe { T::from_pointer(self.data) };
+ }
+}
+
+/// An irq handler.
+pub trait Handler {
+ /// The context data associated with and made available to the handler.
+ type Data: PointerWrapper;
+
+ /// Called from interrupt context when the irq happens.
+ fn handle_irq(data: <Self::Data as PointerWrapper>::Borrowed<'_>) -> Return;
+}
+
+/// The registration of an interrupt handler.
+///
+/// # Examples
+///
+/// The following is an example of a regular handler with a boxed `u32` as data.
+///
+/// ```
+/// # use kernel::prelude::*;
+/// use kernel::irq;
+///
+/// struct Example;
+///
+/// impl irq::Handler for Example {
+/// type Data = Box<u32>;
+///
+/// fn handle_irq(_data: &u32) -> irq::Return {
+/// irq::Return::None
+/// }
+/// }
+///
+/// fn request_irq(irq: u32, data: Box<u32>) -> Result<irq::Registration<Example>> {
+/// irq::Registration::try_new(irq, data, irq::flags::SHARED, fmt!("example_{irq}"))
+/// }
+/// ```
+pub struct Registration<H: Handler>(InternalRegistration<H::Data>);
+
+impl<H: Handler> Registration<H> {
+ /// Registers a new irq handler.
+ ///
+ /// The valid values of `flags` come from the [`flags`] module.
+ pub fn try_new(
+ irq: u32,
+ data: H::Data,
+ flags: usize,
+ name: fmt::Arguments<'_>,
+ ) -> Result<Self> {
+ // SAFETY: `handler` only calls `H::Data::borrow` on `raw_data`.
+ Ok(Self(unsafe {
+ InternalRegistration::try_new(irq, Some(Self::handler), None, flags, data, name)?
+ }))
+ }
+
+ unsafe extern "C" fn handler(
+ _irq: core::ffi::c_int,
+ raw_data: *mut core::ffi::c_void,
+ ) -> bindings::irqreturn_t {
+ // SAFETY: On registration, `into_pointer` was called, so it is safe to borrow from it here
+ // because `from_pointer` is called only after the irq is unregistered.
+ let data = unsafe { H::Data::borrow(raw_data) };
+ H::handle_irq(data) as _
+ }
+}
+
+/// A threaded irq handler.
+pub trait ThreadedHandler {
+ /// The context data associated with and made available to the handlers.
+ type Data: PointerWrapper;
+
+ /// Called from interrupt context when the irq first happens.
+ fn handle_primary_irq(_data: <Self::Data as PointerWrapper>::Borrowed<'_>) -> Return {
+ Return::WakeThread
+ }
+
+ /// Called from the handler thread.
+ fn handle_threaded_irq(data: <Self::Data as PointerWrapper>::Borrowed<'_>) -> Return;
+}
+
+/// The registration of a threaded interrupt handler.
+///
+/// # Examples
+///
+/// The following is an example of a threaded handler with a ref-counted u32 as data:
+///
+/// ```
+/// # use kernel::prelude::*;
+/// use kernel::{
+/// irq,
+/// sync::{Ref, RefBorrow},
+/// };
+///
+/// struct Example;
+///
+/// impl irq::ThreadedHandler for Example {
+/// type Data = Ref<u32>;
+///
+/// fn handle_threaded_irq(_data: RefBorrow<'_, u32>) -> irq::Return {
+/// irq::Return::None
+/// }
+/// }
+///
+/// fn request_irq(irq: u32, data: Ref<u32>) -> Result<irq::ThreadedRegistration<Example>> {
+/// irq::ThreadedRegistration::try_new(irq, data, irq::flags::SHARED, fmt!("example_{irq}"))
+/// }
+/// ```
+pub struct ThreadedRegistration<H: ThreadedHandler>(InternalRegistration<H::Data>);
+
+impl<H: ThreadedHandler> ThreadedRegistration<H> {
+ /// Registers a new threaded irq handler.
+ ///
+ /// The valid values of `flags` come from the [`flags`] module.
+ pub fn try_new(
+ irq: u32,
+ data: H::Data,
+ flags: usize,
+ name: fmt::Arguments<'_>,
+ ) -> Result<Self> {
+ // SAFETY: both `primary_handler` and `threaded_handler` only call `H::Data::borrow` on
+ // `raw_data`.
+ Ok(Self(unsafe {
+ InternalRegistration::try_new(
+ irq,
+ Some(Self::primary_handler),
+ Some(Self::threaded_handler),
+ flags,
+ data,
+ name,
+ )?
+ }))
+ }
+
+ unsafe extern "C" fn primary_handler(
+ _irq: core::ffi::c_int,
+ raw_data: *mut core::ffi::c_void,
+ ) -> bindings::irqreturn_t {
+ // SAFETY: On registration, `into_pointer` was called, so it is safe to borrow from it here
+ // because `from_pointer` is called only after the irq is unregistered.
+ let data = unsafe { H::Data::borrow(raw_data) };
+ H::handle_primary_irq(data) as _
+ }
+
+ unsafe extern "C" fn threaded_handler(
+ _irq: core::ffi::c_int,
+ raw_data: *mut core::ffi::c_void,
+ ) -> bindings::irqreturn_t {
+ // SAFETY: On registration, `into_pointer` was called, so it is safe to borrow from it here
+ // because `from_pointer` is called only after the irq is unregistered.
+ let data = unsafe { H::Data::borrow(raw_data) };
+ H::handle_threaded_irq(data) as _
+ }
+}
+
+/// The return value from interrupt handlers.
+pub enum Return {
+ /// The interrupt was not from this device or was not handled.
+ None = bindings::irqreturn_IRQ_NONE as _,
+
+ /// The interrupt was handled by this device.
+ Handled = bindings::irqreturn_IRQ_HANDLED as _,
+
+ /// The handler wants the handler thread to wake up.
+ WakeThread = bindings::irqreturn_IRQ_WAKE_THREAD as _,
+}
+
+/// Container for interrupt flags.
+pub mod flags {
+ use crate::bindings;
+
+ /// Use the interrupt line as already configured.
+ pub const TRIGGER_NONE: usize = bindings::IRQF_TRIGGER_NONE as _;
+
+ /// The interrupt is triggered when the signal goes from low to high.
+ pub const TRIGGER_RISING: usize = bindings::IRQF_TRIGGER_RISING as _;
+
+ /// The interrupt is triggered when the signal goes from high to low.
+ pub const TRIGGER_FALLING: usize = bindings::IRQF_TRIGGER_FALLING as _;
+
+ /// The interrupt is triggered while the signal is held high.
+ pub const TRIGGER_HIGH: usize = bindings::IRQF_TRIGGER_HIGH as _;
+
+ /// The interrupt is triggered while the signal is held low.
+ pub const TRIGGER_LOW: usize = bindings::IRQF_TRIGGER_LOW as _;
+
+ /// Allow sharing the irq among several devices.
+ pub const SHARED: usize = bindings::IRQF_SHARED as _;
+
+ /// Set by callers when they expect sharing mismatches to occur.
+ pub const PROBE_SHARED: usize = bindings::IRQF_PROBE_SHARED as _;
+
+ /// Flag to mark this interrupt as timer interrupt.
+ pub const TIMER: usize = bindings::IRQF_TIMER as _;
+
+ /// Interrupt is per cpu.
+ pub const PERCPU: usize = bindings::IRQF_PERCPU as _;
+
+ /// Flag to exclude this interrupt from irq balancing.
+ pub const NOBALANCING: usize = bindings::IRQF_NOBALANCING as _;
+
+ /// Interrupt is used for polling (only the interrupt that is registered first in a shared
+ /// interrupt is considered for performance reasons).
+ pub const IRQPOLL: usize = bindings::IRQF_IRQPOLL as _;
+
+ /// Interrupt is not reenabled after the hardirq handler finished. Used by threaded interrupts
+ /// which need to keep the irq line disabled until the threaded handler has been run.
+ pub const ONESHOT: usize = bindings::IRQF_ONESHOT as _;
+
+ /// Do not disable this IRQ during suspend. Does not guarantee that this interrupt will wake
+ /// the system from a suspended state.
+ pub const NO_SUSPEND: usize = bindings::IRQF_NO_SUSPEND as _;
+
+ /// Force enable it on resume even if [`NO_SUSPEND`] is set.
+ pub const FORCE_RESUME: usize = bindings::IRQF_FORCE_RESUME as _;
+
+ /// Interrupt cannot be threaded.
+ pub const NO_THREAD: usize = bindings::IRQF_NO_THREAD as _;
+
+ /// Resume IRQ early during syscore instead of at device resume time.
+ pub const EARLY_RESUME: usize = bindings::IRQF_EARLY_RESUME as _;
+
+ /// If the IRQ is shared with a NO_SUSPEND user, execute this interrupt handler after
+ /// suspending interrupts. For system wakeup devices users need to implement wakeup detection
+ /// in their interrupt handlers.
+ pub const COND_SUSPEND: usize = bindings::IRQF_COND_SUSPEND as _;
+
+ /// Don't enable IRQ or NMI automatically when users request it. Users will enable it
+ /// explicitly by `enable_irq` or `enable_nmi` later.
+ pub const NO_AUTOEN: usize = bindings::IRQF_NO_AUTOEN as _;
+
+ /// Exclude from runnaway detection for IPI and similar handlers, depends on `PERCPU`.
+ pub const NO_DEBUG: usize = bindings::IRQF_NO_DEBUG as _;
+}
+
+/// A guard to call `chained_irq_exit` after `chained_irq_enter` was called.
+///
+/// It is also used as evidence that a previous `chained_irq_enter` was called. So there are no
+/// public constructors and it is only created after indeed calling `chained_irq_enter`.
+pub struct ChainedGuard<'a> {
+ desc: &'a Descriptor,
+ irq_chip: *mut bindings::irq_chip,
+}
+
+impl Drop for ChainedGuard<'_> {
+ fn drop(&mut self) {
+ // SAFETY: The lifetime of `ChainedGuard` guarantees that `self.desc` remains valid, so it
+ // also guarantess `irq_chip` (which was returned from it) and `self.desc.ptr` (guaranteed
+ // by the type invariants).
+ unsafe { bindings::chained_irq_exit(self.irq_chip, self.desc.ptr) };
+ }
+}
+
+/// Wraps the kernel's `struct irq_domain`.
+///
+/// # Invariants
+///
+/// The pointer `Domain::ptr` is non-null and valid.
+#[cfg(CONFIG_IRQ_DOMAIN)]
+pub struct Domain {
+ ptr: *mut bindings::irq_domain,
+}
+
+#[cfg(CONFIG_IRQ_DOMAIN)]
+impl Domain {
+ /// Constructs a new `struct irq_domain` wrapper.
+ ///
+ /// # Safety
+ ///
+ /// The pointer `ptr` must be non-null and valid for the lifetime of the returned object.
+ pub(crate) unsafe fn from_ptr(ptr: *mut bindings::irq_domain) -> Self {
+ // INVARIANT: The safety requirements ensure the invariant.
+ Self { ptr }
+ }
+
+ /// Invokes the chained handler of the given hw irq of the given domain.
+ ///
+ /// It requires evidence that `chained_irq_enter` was called, which is done by passing a
+ /// `ChainedGuard` instance.
+ pub fn generic_handle_chained(&self, hwirq: u32, _guard: &ChainedGuard<'_>) {
+ // SAFETY: `ptr` is valid by the type invariants.
+ unsafe { bindings::generic_handle_domain_irq(self.ptr, hwirq) };
+ }
+}
+
+/// A high-level irq flow handler.
+pub trait FlowHandler {
+ /// The data associated with the handler.
+ type Data: PointerWrapper;
+
+ /// Implements the irq flow for the given descriptor.
+ fn handle_irq_flow(data: <Self::Data as PointerWrapper>::Borrowed<'_>, desc: &Descriptor);
+}
+
+/// Returns the raw irq flow handler corresponding to the (high-level) one defined in `T`.
+///
+/// # Safety
+///
+/// The caller must ensure that the value stored in the irq handler data (as returned by
+/// `irq_desc_get_handler_data`) is the result of calling [`PointerWrapper::into_pointer] for the
+/// [`T::Data`] type.
+pub(crate) unsafe fn new_flow_handler<T: FlowHandler>() -> bindings::irq_flow_handler_t {
+ Some(irq_flow_handler::<T>)
+}
+
+unsafe extern "C" fn irq_flow_handler<T: FlowHandler>(desc: *mut bindings::irq_desc) {
+ // SAFETY: By the safety requirements of `new_flow_handler`, we know that the value returned by
+ // `irq_desc_get_handler_data` comes from calling `T::Data::into_pointer`. `desc` is valid by
+ // the C API contract.
+ let data = unsafe { T::Data::borrow(bindings::irq_desc_get_handler_data(desc)) };
+
+ // SAFETY: The C API guarantees that `desc` is valid for the duration of this call, which
+ // outlives the lifetime returned by `from_desc`.
+ T::handle_irq_flow(data, &unsafe { Descriptor::from_ptr(desc) });
+}
diff --git a/rust/kernel/kasync.rs b/rust/kernel/kasync.rs
new file mode 100644
index 000000000000..d48e9041e804
--- /dev/null
+++ b/rust/kernel/kasync.rs
@@ -0,0 +1,50 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Kernel async functionality.
+
+use core::{
+ future::Future,
+ pin::Pin,
+ task::{Context, Poll},
+};
+
+pub mod executor;
+#[cfg(CONFIG_NET)]
+pub mod net;
+
+/// Yields execution of the current task so that other tasks may execute.
+///
+/// The task continues to be in a "runnable" state though, so it will eventually run again.
+///
+/// # Examples
+///
+/// ```
+/// use kernel::kasync::yield_now;
+///
+/// async fn example() {
+/// pr_info!("Before yield\n");
+/// yield_now().await;
+/// pr_info!("After yield\n");
+/// }
+/// ```
+pub fn yield_now() -> impl Future<Output = ()> {
+ struct Yield {
+ first_poll: bool,
+ }
+
+ impl Future for Yield {
+ type Output = ();
+
+ fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<()> {
+ if !self.first_poll {
+ Poll::Ready(())
+ } else {
+ self.first_poll = false;
+ cx.waker().wake_by_ref();
+ Poll::Pending
+ }
+ }
+ }
+
+ Yield { first_poll: true }
+}
diff --git a/rust/kernel/kasync/executor.rs b/rust/kernel/kasync/executor.rs
new file mode 100644
index 000000000000..e8e55dcfdf35
--- /dev/null
+++ b/rust/kernel/kasync/executor.rs
@@ -0,0 +1,154 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Kernel support for executing futures.
+
+use crate::{
+ sync::{LockClassKey, Ref, RefBorrow},
+ types::PointerWrapper,
+ Result,
+};
+use core::{
+ future::Future,
+ task::{RawWaker, RawWakerVTable, Waker},
+};
+
+pub mod workqueue;
+
+/// Spawns a new task to run in the given executor.
+///
+/// It also automatically defines a new lockdep lock class for executors (e.g., workqueue) that
+/// require one.
+#[macro_export]
+macro_rules! spawn_task {
+ ($executor:expr, $task:expr) => {{
+ static CLASS: $crate::sync::LockClassKey = $crate::sync::LockClassKey::new();
+ $crate::kasync::executor::Executor::spawn($executor, &CLASS, $task)
+ }};
+}
+
+/// A task spawned in an executor.
+pub trait Task {
+ /// Synchronously stops the task.
+ ///
+ /// It ensures that the task won't run again and releases resources needed to run the task
+ /// (e.g., the closure is dropped). If the task is inflight, it waits for the task to block or
+ /// complete before cleaning up and returning.
+ ///
+ /// Callers must not call this from within the task itself as it will likely lead to a
+ /// deadlock.
+ fn sync_stop(self: Ref<Self>);
+}
+
+/// An environment for executing tasks.
+pub trait Executor: Sync + Send {
+ /// Starts executing a task defined by the given future.
+ ///
+ /// Callers are encouraged to use the [`spawn_task`] macro because it automatically defines a
+ /// new lock class key.
+ fn spawn(
+ self: RefBorrow<'_, Self>,
+ lock_class_key: &'static LockClassKey,
+ future: impl Future + 'static + Send,
+ ) -> Result<Ref<dyn Task>>
+ where
+ Self: Sized;
+
+ /// Stops the executor.
+ ///
+ /// After it is called, attempts to spawn new tasks will result in an error and existing ones
+ /// won't be polled anymore.
+ fn stop(&self);
+}
+
+/// A waker that is wrapped in [`Ref`] for its reference counting.
+///
+/// Types that implement this trait can get a [`Waker`] by calling [`ref_waker`].
+pub trait RefWake: Send + Sync {
+ /// Wakes a task up.
+ fn wake_by_ref(self: RefBorrow<'_, Self>);
+
+ /// Wakes a task up and consumes a reference.
+ fn wake(self: Ref<Self>) {
+ self.as_ref_borrow().wake_by_ref();
+ }
+}
+
+/// Creates a [`Waker`] from a [`Ref<T>`], where `T` implements the [`RefWake`] trait.
+pub fn ref_waker<T: 'static + RefWake>(w: Ref<T>) -> Waker {
+ fn raw_waker<T: 'static + RefWake>(w: Ref<T>) -> RawWaker {
+ let data = w.into_pointer();
+ RawWaker::new(
+ data.cast(),
+ &RawWakerVTable::new(clone::<T>, wake::<T>, wake_by_ref::<T>, drop::<T>),
+ )
+ }
+
+ unsafe fn clone<T: 'static + RefWake>(ptr: *const ()) -> RawWaker {
+ // SAFETY: The data stored in the raw waker is the result of a call to `into_pointer`.
+ let w = unsafe { Ref::<T>::borrow(ptr.cast()) };
+ raw_waker(w.into())
+ }
+
+ unsafe fn wake<T: 'static + RefWake>(ptr: *const ()) {
+ // SAFETY: The data stored in the raw waker is the result of a call to `into_pointer`.
+ let w = unsafe { Ref::<T>::from_pointer(ptr.cast()) };
+ w.wake();
+ }
+
+ unsafe fn wake_by_ref<T: 'static + RefWake>(ptr: *const ()) {
+ // SAFETY: The data stored in the raw waker is the result of a call to `into_pointer`.
+ let w = unsafe { Ref::<T>::borrow(ptr.cast()) };
+ w.wake_by_ref();
+ }
+
+ unsafe fn drop<T: 'static + RefWake>(ptr: *const ()) {
+ // SAFETY: The data stored in the raw waker is the result of a call to `into_pointer`.
+ unsafe { Ref::<T>::from_pointer(ptr.cast()) };
+ }
+
+ let raw = raw_waker(w);
+ // SAFETY: The vtable of the raw waker satisfy the behaviour requirements of a waker.
+ unsafe { Waker::from_raw(raw) }
+}
+
+/// A handle to an executor that automatically stops it on drop.
+pub struct AutoStopHandle<T: Executor + ?Sized> {
+ executor: Option<Ref<T>>,
+}
+
+impl<T: Executor + ?Sized> AutoStopHandle<T> {
+ /// Creates a new instance of an [`AutoStopHandle`].
+ pub fn new(executor: Ref<T>) -> Self {
+ Self {
+ executor: Some(executor),
+ }
+ }
+
+ /// Detaches from the auto-stop handle.
+ ///
+ /// That is, extracts the executor from the handle and doesn't stop it anymore.
+ pub fn detach(mut self) -> Ref<T> {
+ self.executor.take().unwrap()
+ }
+
+ /// Returns the executor associated with the auto-stop handle.
+ ///
+ /// This is so that callers can, for example, spawn new tasks.
+ pub fn executor(&self) -> RefBorrow<'_, T> {
+ self.executor.as_ref().unwrap().as_ref_borrow()
+ }
+}
+
+impl<T: Executor + ?Sized> Drop for AutoStopHandle<T> {
+ fn drop(&mut self) {
+ if let Some(ex) = self.executor.take() {
+ ex.stop();
+ }
+ }
+}
+
+impl<T: 'static + Executor> From<AutoStopHandle<T>> for AutoStopHandle<dyn Executor> {
+ fn from(src: AutoStopHandle<T>) -> Self {
+ Self::new(src.detach())
+ }
+}
diff --git a/rust/kernel/kasync/executor/workqueue.rs b/rust/kernel/kasync/executor/workqueue.rs
new file mode 100644
index 000000000000..81cd16880600
--- /dev/null
+++ b/rust/kernel/kasync/executor/workqueue.rs
@@ -0,0 +1,291 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Kernel support for executing futures in C workqueues (`struct workqueue_struct`).
+
+use super::{AutoStopHandle, RefWake};
+use crate::{
+ error::code::*,
+ mutex_init,
+ revocable::AsyncRevocable,
+ sync::{LockClassKey, Mutex, Ref, RefBorrow, UniqueRef},
+ unsafe_list,
+ workqueue::{BoxedQueue, Queue, Work, WorkAdapter},
+ Either, Left, Result, Right,
+};
+use core::{cell::UnsafeCell, future::Future, marker::PhantomPinned, pin::Pin, task::Context};
+
+trait RevocableTask {
+ fn revoke(&self);
+ fn flush(self: Ref<Self>);
+ fn to_links(&self) -> &unsafe_list::Links<dyn RevocableTask>;
+}
+
+// SAFETY: `Task` has a single `links` field and only one adapter.
+unsafe impl unsafe_list::Adapter for dyn RevocableTask {
+ type EntryType = dyn RevocableTask;
+ fn to_links(obj: &dyn RevocableTask) -> &unsafe_list::Links<dyn RevocableTask> {
+ obj.to_links()
+ }
+}
+
+struct Task<T: 'static + Send + Future> {
+ links: unsafe_list::Links<dyn RevocableTask>,
+ executor: Ref<Executor>,
+ work: Work,
+ future: AsyncRevocable<UnsafeCell<T>>,
+}
+
+// SAFETY: The `future` field is only used by one thread at a time (in the `poll` method, which is
+// called by the work queue, who guarantees no reentrancy), so a task is `Sync` as long as the
+// future is `Send`.
+unsafe impl<T: 'static + Send + Future> Sync for Task<T> {}
+
+// SAFETY: If the future `T` is `Send`, so is the task.
+unsafe impl<T: 'static + Send + Future> Send for Task<T> {}
+
+impl<T: 'static + Send + Future> Task<T> {
+ fn try_new(
+ executor: Ref<Executor>,
+ key: &'static LockClassKey,
+ future: T,
+ ) -> Result<Ref<Self>> {
+ let task = UniqueRef::try_new(Self {
+ executor: executor.clone(),
+ links: unsafe_list::Links::new(),
+ // SAFETY: `work` is initialised below.
+ work: unsafe { Work::new() },
+ future: AsyncRevocable::new(UnsafeCell::new(future)),
+ })?;
+
+ Work::init(&task, key);
+
+ let task = Ref::from(task);
+
+ // Add task to list.
+ {
+ let mut guard = executor.inner.lock();
+ if guard.stopped {
+ return Err(EINVAL);
+ }
+
+ // Convert one reference into a pointer so that we hold on to a ref count while the
+ // task is in the list.
+ Ref::into_raw(task.clone());
+
+ // SAFETY: The task was just created, so it is not in any other lists. It remains alive
+ // because we incremented the refcount to account for it being in the list. It never
+ // moves because it's pinned behind a `Ref`.
+ unsafe { guard.tasks.push_back(&*task) };
+ }
+
+ Ok(task)
+ }
+}
+
+unsafe impl<T: 'static + Send + Future> WorkAdapter for Task<T> {
+ type Target = Self;
+ const FIELD_OFFSET: isize = crate::offset_of!(Self, work);
+ fn run(task: Ref<Task<T>>) {
+ let waker = super::ref_waker(task.clone());
+ let mut ctx = Context::from_waker(&waker);
+
+ let guard = if let Some(g) = task.future.try_access() {
+ g
+ } else {
+ return;
+ };
+
+ // SAFETY: `future` is pinned when the task is. The task is pinned because it's behind a
+ // `Ref`, which is always pinned.
+ //
+ // Work queues guarantee no reentrancy and this is the only place where the future is
+ // dereferenced, so it's ok to do it mutably.
+ let future = unsafe { Pin::new_unchecked(&mut *guard.get()) };
+ if future.poll(&mut ctx).is_ready() {
+ drop(guard);
+ task.revoke();
+ }
+ }
+}
+
+impl<T: 'static + Send + Future> super::Task for Task<T> {
+ fn sync_stop(self: Ref<Self>) {
+ self.revoke();
+ self.flush();
+ }
+}
+
+impl<T: 'static + Send + Future> RevocableTask for Task<T> {
+ fn revoke(&self) {
+ if !self.future.revoke() {
+ // Nothing to do if the task was already revoked.
+ return;
+ }
+
+ // SAFETY: The object is inserted into the list on creation and only removed when the
+ // future is first revoked. (Subsequent revocations don't result in additional attempts
+ // to remove per the check above.)
+ unsafe { self.executor.inner.lock().tasks.remove(self) };
+
+ // Decrement the refcount now that the task is no longer in the list.
+ //
+ // SAFETY: `into_raw` was called from `try_new` when the task was added to the list.
+ unsafe { Ref::from_raw(self) };
+ }
+
+ fn flush(self: Ref<Self>) {
+ self.work.cancel();
+ }
+
+ fn to_links(&self) -> &unsafe_list::Links<dyn RevocableTask> {
+ &self.links
+ }
+}
+
+impl<T: 'static + Send + Future> RefWake for Task<T> {
+ fn wake(self: Ref<Self>) {
+ if self.future.is_revoked() {
+ return;
+ }
+
+ match &self.executor.queue {
+ Left(q) => &**q,
+ Right(q) => *q,
+ }
+ .enqueue(self.clone());
+ }
+
+ fn wake_by_ref(self: RefBorrow<'_, Self>) {
+ Ref::from(self).wake();
+ }
+}
+
+struct ExecutorInner {
+ stopped: bool,
+ tasks: unsafe_list::List<dyn RevocableTask>,
+}
+
+/// An executor backed by a work queue.
+///
+/// # Examples
+///
+/// The following example runs two tasks on the shared system workqueue.
+///
+/// ```
+/// # use kernel::prelude::*;
+/// use kernel::kasync::executor::workqueue::Executor;
+/// use kernel::spawn_task;
+/// use kernel::workqueue;
+///
+/// fn example_shared_workqueue() -> Result {
+/// let mut handle = Executor::try_new(workqueue::system())?;
+/// spawn_task!(handle.executor(), async {
+/// pr_info!("First workqueue task\n");
+/// })?;
+/// spawn_task!(handle.executor(), async {
+/// pr_info!("Second workqueue task\n");
+/// })?;
+/// handle.detach();
+/// Ok(())
+/// }
+///
+/// # example_shared_workqueue().unwrap();
+/// ```
+pub struct Executor {
+ queue: Either<BoxedQueue, &'static Queue>,
+ inner: Mutex<ExecutorInner>,
+ _pin: PhantomPinned,
+}
+
+// SAFETY: The executor is backed by a kernel `struct workqueue_struct`, which works from any
+// thread.
+unsafe impl Send for Executor {}
+
+// SAFETY: The executor is backed by a kernel `struct workqueue_struct`, which can be used
+// concurrently by multiple threads.
+unsafe impl Sync for Executor {}
+
+impl Executor {
+ /// Creates a new workqueue-based executor using a static work queue.
+ pub fn try_new(wq: &'static Queue) -> Result<AutoStopHandle<Self>> {
+ Self::new_internal(Right(wq))
+ }
+
+ /// Creates a new workqueue-based executor using an owned (boxed) work queue.
+ pub fn try_new_owned(wq: BoxedQueue) -> Result<AutoStopHandle<Self>> {
+ Self::new_internal(Left(wq))
+ }
+
+ /// Creates a new workqueue-based executor.
+ ///
+ /// It uses the given work queue to run its tasks.
+ fn new_internal(queue: Either<BoxedQueue, &'static Queue>) -> Result<AutoStopHandle<Self>> {
+ let mut e = Pin::from(UniqueRef::try_new(Self {
+ queue,
+ _pin: PhantomPinned,
+ // SAFETY: `mutex_init` is called below.
+ inner: unsafe {
+ Mutex::new(ExecutorInner {
+ stopped: false,
+ tasks: unsafe_list::List::new(),
+ })
+ },
+ })?);
+ // SAFETY: `tasks` is pinned when the executor is.
+ let pinned = unsafe { e.as_mut().map_unchecked_mut(|e| &mut e.inner) };
+ mutex_init!(pinned, "Executor::inner");
+
+ Ok(AutoStopHandle::new(e.into()))
+ }
+}
+
+impl super::Executor for Executor {
+ fn spawn(
+ self: RefBorrow<'_, Self>,
+ key: &'static LockClassKey,
+ future: impl Future + 'static + Send,
+ ) -> Result<Ref<dyn super::Task>> {
+ let task = Task::try_new(self.into(), key, future)?;
+ task.clone().wake();
+ Ok(task)
+ }
+
+ fn stop(&self) {
+ // Set the `stopped` flag.
+ self.inner.lock().stopped = true;
+
+ // Go through all tasks and revoke & flush them.
+ //
+ // N.B. If we decide to allow "asynchronous" stops, we need to ensure that tasks that have
+ // been revoked but not flushed yet remain in the list so that we can flush them here.
+ // Otherwise we may have a race where we may have a running task (was revoked while
+ // running) that isn't the list anymore, so we think we've synchronously stopped all tasks
+ // when we haven't really -- unloading a module in this situation leads to memory safety
+ // issues (running unloaded code).
+ loop {
+ let guard = self.inner.lock();
+
+ let front = if let Some(t) = guard.tasks.front() {
+ t
+ } else {
+ break;
+ };
+
+ // Get a new reference to the task.
+ //
+ // SAFETY: We know all entries in the list are of type `Ref<dyn RevocableTask>` and
+ // that a reference exists while the entry is in the list, and since we are holding the
+ // list lock, we know it cannot go away. The `into_raw` call below ensures that we
+ // don't decrement the refcount accidentally.
+ let tasktmp = unsafe { Ref::<dyn RevocableTask>::from_raw(front.as_ptr()) };
+ let task = tasktmp.clone();
+ Ref::into_raw(tasktmp);
+
+ // Release the mutex before revoking the task.
+ drop(guard);
+
+ task.revoke();
+ task.flush();
+ }
+ }
+}
diff --git a/rust/kernel/kasync/net.rs b/rust/kernel/kasync/net.rs
new file mode 100644
index 000000000000..b4bbeffad94a
--- /dev/null
+++ b/rust/kernel/kasync/net.rs
@@ -0,0 +1,322 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Async networking.
+
+use crate::{bindings, error::code::*, net, sync::NoWaitLock, types::Opaque, Result};
+use core::{
+ future::Future,
+ marker::{PhantomData, PhantomPinned},
+ ops::Deref,
+ pin::Pin,
+ task::{Context, Poll, Waker},
+};
+
+/// A socket listening on a TCP port.
+///
+/// The [`TcpListener::accept`] method is meant to be used in async contexts.
+pub struct TcpListener {
+ listener: net::TcpListener,
+}
+
+impl TcpListener {
+ /// Creates a new TCP listener.
+ ///
+ /// It is configured to listen on the given socket address for the given namespace.
+ pub fn try_new(ns: &net::Namespace, addr: &net::SocketAddr) -> Result<Self> {
+ Ok(Self {
+ listener: net::TcpListener::try_new(ns, addr)?,
+ })
+ }
+
+ /// Accepts a new connection.
+ ///
+ /// Returns a future that when ready indicates the result of the accept operation; on success,
+ /// it contains the newly-accepted tcp stream.
+ pub fn accept(&self) -> impl Future<Output = Result<TcpStream>> + '_ {
+ SocketFuture::from_listener(
+ self,
+ bindings::BINDINGS_EPOLLIN | bindings::BINDINGS_EPOLLERR,
+ || {
+ Ok(TcpStream {
+ stream: self.listener.accept(false)?,
+ })
+ },
+ )
+ }
+}
+
+impl Deref for TcpListener {
+ type Target = net::TcpListener;
+
+ fn deref(&self) -> &Self::Target {
+ &self.listener
+ }
+}
+
+/// A connected TCP socket.
+///
+/// The potentially blocking methods (e.g., [`TcpStream::read`], [`TcpStream::write`]) are meant
+/// to be used in async contexts.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::prelude::*;
+/// # use kernel::kasync::net::TcpStream;
+/// async fn echo_server(stream: TcpStream) -> Result {
+/// let mut buf = [0u8; 1024];
+/// loop {
+/// let n = stream.read(&mut buf).await?;
+/// if n == 0 {
+/// return Ok(());
+/// }
+/// stream.write_all(&buf[..n]).await?;
+/// }
+/// }
+/// ```
+pub struct TcpStream {
+ stream: net::TcpStream,
+}
+
+impl TcpStream {
+ /// Reads data from a connected socket.
+ ///
+ /// Returns a future that when ready indicates the result of the read operation; on success, it
+ /// contains the number of bytes read, which will be zero if the connection is closed.
+ pub fn read<'a>(&'a self, buf: &'a mut [u8]) -> impl Future<Output = Result<usize>> + 'a {
+ SocketFuture::from_stream(
+ self,
+ bindings::BINDINGS_EPOLLIN | bindings::BINDINGS_EPOLLHUP | bindings::BINDINGS_EPOLLERR,
+ || self.stream.read(buf, false),
+ )
+ }
+
+ /// Writes data to the connected socket.
+ ///
+ /// Returns a future that when ready indicates the result of the write operation; on success, it
+ /// contains the number of bytes written.
+ pub fn write<'a>(&'a self, buf: &'a [u8]) -> impl Future<Output = Result<usize>> + 'a {
+ SocketFuture::from_stream(
+ self,
+ bindings::BINDINGS_EPOLLOUT | bindings::BINDINGS_EPOLLHUP | bindings::BINDINGS_EPOLLERR,
+ || self.stream.write(buf, false),
+ )
+ }
+
+ /// Writes all the data to the connected socket.
+ ///
+ /// Returns a future that when ready indicates the result of the write operation; on success, it
+ /// has written all the data.
+ pub async fn write_all<'a>(&'a self, buf: &'a [u8]) -> Result {
+ let mut rem = buf;
+
+ while !rem.is_empty() {
+ let n = self.write(rem).await?;
+ rem = &rem[n..];
+ }
+
+ Ok(())
+ }
+}
+
+impl Deref for TcpStream {
+ type Target = net::TcpStream;
+
+ fn deref(&self) -> &Self::Target {
+ &self.stream
+ }
+}
+
+/// A future for a socket operation.
+///
+/// # Invariants
+///
+/// `sock` is always non-null and valid for the duration of the lifetime of the instance.
+struct SocketFuture<'a, Out, F: FnMut() -> Result<Out> + Send + 'a> {
+ sock: *mut bindings::socket,
+ mask: u32,
+ is_queued: bool,
+ wq_entry: Opaque<bindings::wait_queue_entry>,
+ waker: NoWaitLock<Option<Waker>>,
+ _p: PhantomData<&'a ()>,
+ _pin: PhantomPinned,
+ operation: F,
+}
+
+// SAFETY: A kernel socket can be used from any thread, `wq_entry` is only used on drop and when
+// `is_queued` is initially `false`.
+unsafe impl<Out, F: FnMut() -> Result<Out> + Send> Send for SocketFuture<'_, Out, F> {}
+
+impl<'a, Out, F: FnMut() -> Result<Out> + Send + 'a> SocketFuture<'a, Out, F> {
+ /// Creates a new socket future.
+ ///
+ /// # Safety
+ ///
+ /// Callers must ensure that `sock` is non-null, valid, and remains valid for the lifetime
+ /// (`'a`) of the returned instance.
+ unsafe fn new(sock: *mut bindings::socket, mask: u32, operation: F) -> Self {
+ Self {
+ sock,
+ mask,
+ is_queued: false,
+ wq_entry: Opaque::uninit(),
+ waker: NoWaitLock::new(None),
+ operation,
+ _p: PhantomData,
+ _pin: PhantomPinned,
+ }
+ }
+
+ /// Creates a new socket future for a tcp listener.
+ fn from_listener(listener: &'a TcpListener, mask: u32, operation: F) -> Self {
+ // SAFETY: The socket is guaranteed to remain valid because it is bound to the reference to
+ // the listener (whose existence guarantees the socket remains valid).
+ unsafe { Self::new(listener.listener.sock, mask, operation) }
+ }
+
+ /// Creates a new socket future for a tcp stream.
+ fn from_stream(stream: &'a TcpStream, mask: u32, operation: F) -> Self {
+ // SAFETY: The socket is guaranteed to remain valid because it is bound to the reference to
+ // the stream (whose existence guarantees the socket remains valid).
+ unsafe { Self::new(stream.stream.sock, mask, operation) }
+ }
+
+ /// Callback called when the socket changes state.
+ ///
+ /// If the state matches the one we're waiting on, we wake up the task so that the future can be
+ /// polled again.
+ unsafe extern "C" fn wake_callback(
+ wq_entry: *mut bindings::wait_queue_entry,
+ _mode: core::ffi::c_uint,
+ _flags: core::ffi::c_int,
+ key: *mut core::ffi::c_void,
+ ) -> core::ffi::c_int {
+ let mask = key as u32;
+
+ // SAFETY: The future is valid while this callback is called because we remove from the
+ // queue on drop.
+ //
+ // There is a potential soundness issue here because we're generating a shared reference to
+ // `Self` while `Self::poll` has a mutable (unique) reference. However, for `!Unpin` types
+ // (like `Self`), `&mut T` is treated as `*mut T` per
+ // <https://github.com/rust-lang/rust/issues/63818> -- so we avoid the unsoundness. Once a
+ // more definitive solution is available, we can change this to use it.
+ let s = unsafe { &*crate::container_of!(wq_entry, Self, wq_entry) };
+ if mask & s.mask == 0 {
+ // Nothing to do as this notification doesn't interest us.
+ return 0;
+ }
+
+ // If we can't acquire the waker lock, the waker is in the process of being modified. Our
+ // attempt to acquire the lock will be reported to the lock owner, so it will trigger the
+ // wake up.
+ if let Some(guard) = s.waker.try_lock() {
+ if let Some(ref w) = *guard {
+ let cloned = w.clone();
+ drop(guard);
+ cloned.wake();
+ return 1;
+ }
+ }
+ 0
+ }
+
+ /// Poll the future once.
+ ///
+ /// It calls the operation and converts `EAGAIN` errors into a pending state.
+ fn poll_once(self: Pin<&mut Self>) -> Poll<Result<Out>> {
+ // SAFETY: We never move out of `this`.
+ let this = unsafe { self.get_unchecked_mut() };
+ match (this.operation)() {
+ Ok(s) => Poll::Ready(Ok(s)),
+ Err(e) => {
+ if e == EAGAIN {
+ Poll::Pending
+ } else {
+ Poll::Ready(Err(e))
+ }
+ }
+ }
+ }
+
+ /// Updates the waker stored in the future.
+ ///
+ /// It automatically triggers a wake up on races with the reactor.
+ fn set_waker(&self, waker: &Waker) {
+ if let Some(mut guard) = self.waker.try_lock() {
+ let old = core::mem::replace(&mut *guard, Some(waker.clone()));
+ let contention = guard.unlock();
+ drop(old);
+ if !contention {
+ return;
+ }
+ }
+
+ // We either couldn't store the waker because the existing one is being awakened, or the
+ // reactor tried to acquire the lock while we held it (contention). In either case, we just
+ // wake it up to ensure we don't miss any notification.
+ waker.wake_by_ref();
+ }
+}
+
+impl<Out, F: FnMut() -> Result<Out> + Send> Future for SocketFuture<'_, Out, F> {
+ type Output = Result<Out>;
+
+ fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
+ match self.as_mut().poll_once() {
+ Poll::Ready(r) => Poll::Ready(r),
+ Poll::Pending => {
+ // Store away the latest waker every time we may `Pending`.
+ self.set_waker(cx.waker());
+ if self.is_queued {
+ // Nothing else to do was the waiter is already queued.
+ return Poll::Pending;
+ }
+
+ // SAFETY: We never move out of `this`.
+ let this = unsafe { self.as_mut().get_unchecked_mut() };
+
+ this.is_queued = true;
+
+ // SAFETY: `wq_entry` is valid for write.
+ unsafe {
+ bindings::init_waitqueue_func_entry(
+ this.wq_entry.get(),
+ Some(Self::wake_callback),
+ )
+ };
+
+ // SAFETY: `wq_entry` was just initialised above and is valid for read/write.
+ // By the type invariants, the socket is always valid.
+ unsafe {
+ bindings::add_wait_queue(
+ core::ptr::addr_of_mut!((*this.sock).wq.wait),
+ this.wq_entry.get(),
+ )
+ };
+
+ // If the future wasn't queued yet, we need to poll again in case it reached
+ // the desired state between the last poll and being queued (in which case we
+ // would have missed the notification).
+ self.poll_once()
+ }
+ }
+ }
+}
+
+impl<Out, F: FnMut() -> Result<Out> + Send> Drop for SocketFuture<'_, Out, F> {
+ fn drop(&mut self) {
+ if !self.is_queued {
+ return;
+ }
+
+ // SAFETY: `wq_entry` is initialised because `is_queued` is set to `true`, so it is valid
+ // for read/write. By the type invariants, the socket is always valid.
+ unsafe {
+ bindings::remove_wait_queue(
+ core::ptr::addr_of_mut!((*self.sock).wq.wait),
+ self.wq_entry.get(),
+ )
+ };
+ }
+}
diff --git a/rust/kernel/kunit.rs b/rust/kernel/kunit.rs
new file mode 100644
index 000000000000..5f3e102962c3
--- /dev/null
+++ b/rust/kernel/kunit.rs
@@ -0,0 +1,91 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! KUnit-based macros for Rust unit tests.
+//!
+//! C header: [`include/kunit/test.h`](../../../../../include/kunit/test.h)
+//!
+//! Reference: <https://www.kernel.org/doc/html/latest/dev-tools/kunit/index.html>
+
+/// Asserts that a boolean expression is `true` at runtime.
+///
+/// Public but hidden since it should only be used from generated tests.
+///
+/// Unlike the one in `core`, this one does not panic; instead, it is mapped to the KUnit
+/// facilities. See [`assert!`] for more details.
+#[doc(hidden)]
+#[macro_export]
+macro_rules! kunit_assert {
+ ($test:expr, $cond:expr $(,)?) => {{
+ if !$cond {
+ #[repr(transparent)]
+ struct Location($crate::bindings::kunit_loc);
+
+ #[repr(transparent)]
+ struct UnaryAssert($crate::bindings::kunit_unary_assert);
+
+ // SAFETY: There is only a static instance and in that one the pointer field
+ // points to an immutable C string.
+ unsafe impl Sync for Location {}
+
+ // SAFETY: There is only a static instance and in that one the pointer field
+ // points to an immutable C string.
+ unsafe impl Sync for UnaryAssert {}
+
+ static FILE: &'static $crate::str::CStr = $crate::c_str!(core::file!());
+ static LOCATION: Location = Location($crate::bindings::kunit_loc {
+ file: FILE.as_char_ptr(),
+ line: core::line!() as i32,
+ });
+ static CONDITION: &'static $crate::str::CStr = $crate::c_str!(stringify!($cond));
+ static ASSERTION: UnaryAssert = UnaryAssert($crate::bindings::kunit_unary_assert {
+ assert: $crate::bindings::kunit_assert {
+ format: Some($crate::bindings::kunit_unary_assert_format),
+ },
+ condition: CONDITION.as_char_ptr(),
+ expected_true: true,
+ });
+
+ // SAFETY:
+ // - FFI call.
+ // - The `test` pointer is valid because this hidden macro should only be called by
+ // the generated documentation tests which forward the test pointer given by KUnit.
+ // - The string pointers (`file` and `condition`) point to null-terminated ones.
+ // - The function pointer (`format`) points to the proper function.
+ // - The pointers passed will remain valid since they point to statics.
+ // - The format string is allowed to be null.
+ // - There are, however, problems with this: first of all, this will end up stopping
+ // the thread, without running destructors. While that is problematic in itself,
+ // it is considered UB to have what is effectively an forced foreign unwind
+ // with `extern "C"` ABI. One could observe the stack that is now gone from
+ // another thread. We should avoid pinning stack variables to prevent library UB,
+ // too. For the moment, given test failures are reported immediately before the
+ // next test runs, that test failures should be fixed and that KUnit is explicitly
+ // documented as not suitable for production environments, we feel it is reasonable.
+ unsafe {
+ $crate::bindings::kunit_do_failed_assertion(
+ $test,
+ core::ptr::addr_of!(LOCATION.0),
+ $crate::bindings::kunit_assert_type_KUNIT_ASSERTION,
+ core::ptr::addr_of!(ASSERTION.0.assert),
+ core::ptr::null(),
+ );
+ }
+ }
+ }};
+}
+
+/// Asserts that two expressions are equal to each other (using [`PartialEq`]).
+///
+/// Public but hidden since it should only be used from generated tests.
+///
+/// Unlike the one in `core`, this one does not panic; instead, it is mapped to the KUnit
+/// facilities. See [`assert!`] for more details.
+#[doc(hidden)]
+#[macro_export]
+macro_rules! kunit_assert_eq {
+ ($test:expr, $left:expr, $right:expr $(,)?) => {{
+ // For the moment, we just forward to the expression assert because,
+ // for binary asserts, KUnit supports only a few types (e.g. integers).
+ $crate::kunit_assert!($test, $left == $right);
+ }};
+}
diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
new file mode 100644
index 000000000000..b55fe00761c2
--- /dev/null
+++ b/rust/kernel/lib.rs
@@ -0,0 +1,267 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! The `kernel` crate.
+//!
+//! This crate contains the kernel APIs that have been ported or wrapped for
+//! usage by Rust code in the kernel and is shared by all of them.
+//!
+//! In other words, all the rest of the Rust code in the kernel (e.g. kernel
+//! modules written in Rust) depends on [`core`], [`alloc`] and this crate.
+//!
+//! If you need a kernel C API that is not ported or wrapped yet here, then
+//! do so first instead of bypassing this crate.
+
+#![no_std]
+#![feature(allocator_api)]
+#![feature(associated_type_defaults)]
+#![feature(coerce_unsized)]
+#![feature(const_mut_refs)]
+#![feature(const_ptr_offset_from)]
+#![feature(const_refs_to_cell)]
+#![feature(const_trait_impl)]
+#![feature(core_ffi_c)]
+#![feature(c_size_t)]
+#![feature(dispatch_from_dyn)]
+#![feature(doc_cfg)]
+#![feature(duration_constants)]
+#![feature(generic_associated_types)]
+#![feature(ptr_metadata)]
+#![feature(receiver_trait)]
+#![feature(unsize)]
+
+// Ensure conditional compilation based on the kernel configuration works;
+// otherwise we may silently break things like initcall handling.
+#[cfg(not(CONFIG_RUST))]
+compile_error!("Missing kernel configuration for conditional compilation");
+
+#[cfg(not(test))]
+#[cfg(not(testlib))]
+mod allocator;
+
+#[doc(hidden)]
+pub use bindings;
+
+pub use macros;
+
+#[cfg(CONFIG_ARM_AMBA)]
+pub mod amba;
+pub mod chrdev;
+#[cfg(CONFIG_COMMON_CLK)]
+pub mod clk;
+pub mod cred;
+pub mod delay;
+pub mod device;
+pub mod driver;
+pub mod error;
+pub mod file;
+pub mod fs;
+pub mod gpio;
+pub mod hwrng;
+pub mod irq;
+pub mod kasync;
+pub mod miscdev;
+pub mod mm;
+#[cfg(CONFIG_NET)]
+pub mod net;
+pub mod pages;
+pub mod power;
+pub mod revocable;
+pub mod security;
+pub mod str;
+pub mod task;
+pub mod workqueue;
+
+pub mod linked_list;
+mod raw_list;
+pub mod rbtree;
+pub mod unsafe_list;
+
+#[doc(hidden)]
+pub mod module_param;
+
+mod build_assert;
+pub mod prelude;
+pub mod print;
+pub mod random;
+mod static_assert;
+#[doc(hidden)]
+pub mod std_vendor;
+pub mod sync;
+
+#[cfg(any(CONFIG_SYSCTL, doc))]
+#[doc(cfg(CONFIG_SYSCTL))]
+pub mod sysctl;
+
+pub mod io_buffer;
+#[cfg(CONFIG_HAS_IOMEM)]
+pub mod io_mem;
+pub mod iov_iter;
+pub mod of;
+pub mod platform;
+mod types;
+pub mod user_ptr;
+
+#[cfg(CONFIG_KUNIT)]
+pub mod kunit;
+
+#[doc(hidden)]
+pub use build_error::build_error;
+
+pub use crate::error::{to_result, Error, Result};
+pub use crate::types::{
+ bit, bits_iter, ARef, AlwaysRefCounted, Bool, Either, Either::Left, Either::Right, False, Mode,
+ Opaque, PointerWrapper, ScopeGuard, True,
+};
+
+use core::marker::PhantomData;
+
+/// Page size defined in terms of the `PAGE_SHIFT` macro from C.
+///
+/// [`PAGE_SHIFT`]: ../../../include/asm-generic/page.h
+pub const PAGE_SIZE: usize = 1 << bindings::PAGE_SHIFT;
+
+/// Prefix to appear before log messages printed from within the kernel crate.
+const __LOG_PREFIX: &[u8] = b"rust_kernel\0";
+
+/// The top level entrypoint to implementing a kernel module.
+///
+/// For any teardown or cleanup operations, your type may implement [`Drop`].
+pub trait Module: Sized + Sync {
+ /// Called at module initialization time.
+ ///
+ /// Use this method to perform whatever setup or registration your module
+ /// should do.
+ ///
+ /// Equivalent to the `module_init` macro in the C API.
+ fn init(name: &'static str::CStr, module: &'static ThisModule) -> Result<Self>;
+}
+
+/// Equivalent to `THIS_MODULE` in the C API.
+///
+/// C header: `include/linux/export.h`
+pub struct ThisModule(*mut bindings::module);
+
+// SAFETY: `THIS_MODULE` may be used from all threads within a module.
+unsafe impl Sync for ThisModule {}
+
+impl ThisModule {
+ /// Creates a [`ThisModule`] given the `THIS_MODULE` pointer.
+ ///
+ /// # Safety
+ ///
+ /// The pointer must be equal to the right `THIS_MODULE`.
+ pub const unsafe fn from_ptr(ptr: *mut bindings::module) -> ThisModule {
+ ThisModule(ptr)
+ }
+
+ /// Locks the module parameters to access them.
+ ///
+ /// Returns a [`KParamGuard`] that will release the lock when dropped.
+ pub fn kernel_param_lock(&self) -> KParamGuard<'_> {
+ // SAFETY: `kernel_param_lock` will check if the pointer is null and
+ // use the built-in mutex in that case.
+ #[cfg(CONFIG_SYSFS)]
+ unsafe {
+ bindings::kernel_param_lock(self.0)
+ }
+
+ KParamGuard {
+ #[cfg(CONFIG_SYSFS)]
+ this_module: self,
+ phantom: PhantomData,
+ }
+ }
+}
+
+/// Scoped lock on the kernel parameters of [`ThisModule`].
+///
+/// Lock will be released when this struct is dropped.
+pub struct KParamGuard<'a> {
+ #[cfg(CONFIG_SYSFS)]
+ this_module: &'a ThisModule,
+ phantom: PhantomData<&'a ()>,
+}
+
+#[cfg(CONFIG_SYSFS)]
+impl<'a> Drop for KParamGuard<'a> {
+ fn drop(&mut self) {
+ // SAFETY: `kernel_param_lock` will check if the pointer is null and
+ // use the built-in mutex in that case. The existence of `self`
+ // guarantees that the lock is held.
+ unsafe { bindings::kernel_param_unlock(self.this_module.0) }
+ }
+}
+
+/// Calculates the offset of a field from the beginning of the struct it belongs to.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::prelude::*;
+/// # use kernel::offset_of;
+/// struct Test {
+/// a: u64,
+/// b: u32,
+/// }
+///
+/// assert_eq!(offset_of!(Test, b), 8);
+/// ```
+#[macro_export]
+macro_rules! offset_of {
+ ($type:ty, $($f:tt)*) => {{
+ let tmp = core::mem::MaybeUninit::<$type>::uninit();
+ let outer = tmp.as_ptr();
+ // To avoid warnings when nesting `unsafe` blocks.
+ #[allow(unused_unsafe)]
+ // SAFETY: The pointer is valid and aligned, just not initialised; `addr_of` ensures that
+ // we don't actually read from `outer` (which would be UB) nor create an intermediate
+ // reference.
+ let inner = unsafe { core::ptr::addr_of!((*outer).$($f)*) } as *const u8;
+ // To avoid warnings when nesting `unsafe` blocks.
+ #[allow(unused_unsafe)]
+ // SAFETY: The two pointers are within the same allocation block.
+ unsafe { inner.offset_from(outer as *const u8) }
+ }}
+}
+
+/// Produces a pointer to an object from a pointer to one of its fields.
+///
+/// # Safety
+///
+/// Callers must ensure that the pointer to the field is in fact a pointer to the specified field,
+/// as opposed to a pointer to another object of the same type. If this condition is not met,
+/// any dereference of the resulting pointer is UB.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::container_of;
+/// struct Test {
+/// a: u64,
+/// b: u32,
+/// }
+///
+/// let test = Test { a: 10, b: 20 };
+/// let b_ptr = &test.b;
+/// let test_alias = container_of!(b_ptr, Test, b);
+/// assert!(core::ptr::eq(&test, test_alias));
+/// ```
+#[macro_export]
+macro_rules! container_of {
+ ($ptr:expr, $type:ty, $($f:tt)*) => {{
+ let ptr = $ptr as *const _ as *const u8;
+ let offset = $crate::offset_of!($type, $($f)*);
+ ptr.wrapping_offset(-offset) as *const $type
+ }}
+}
+
+#[cfg(not(any(testlib, test)))]
+#[panic_handler]
+fn panic(info: &core::panic::PanicInfo<'_>) -> ! {
+ pr_emerg!("{}\n", info);
+ // SAFETY: FFI call.
+ unsafe { bindings::BUG() };
+ // Bindgen currently does not recognize `__noreturn` so `BUG` returns `()`
+ // instead of `!`. See <https://github.com/rust-lang/rust-bindgen/issues/2094>.
+ loop {}
+}
diff --git a/rust/kernel/linked_list.rs b/rust/kernel/linked_list.rs
new file mode 100644
index 000000000000..3330edcc7ca8
--- /dev/null
+++ b/rust/kernel/linked_list.rs
@@ -0,0 +1,247 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Linked lists.
+//!
+//! TODO: This module is a work in progress.
+
+use alloc::boxed::Box;
+use core::ptr::NonNull;
+
+pub use crate::raw_list::{Cursor, GetLinks, Links};
+use crate::{raw_list, raw_list::RawList, sync::Ref};
+
+// TODO: Use the one from `kernel::file_operations::PointerWrapper` instead.
+/// Wraps an object to be inserted in a linked list.
+pub trait Wrapper<T: ?Sized> {
+ /// Converts the wrapped object into a pointer that represents it.
+ fn into_pointer(self) -> NonNull<T>;
+
+ /// Converts the object back from the pointer representation.
+ ///
+ /// # Safety
+ ///
+ /// The passed pointer must come from a previous call to [`Wrapper::into_pointer()`].
+ unsafe fn from_pointer(ptr: NonNull<T>) -> Self;
+
+ /// Returns a reference to the wrapped object.
+ fn as_ref(&self) -> &T;
+}
+
+impl<T: ?Sized> Wrapper<T> for Box<T> {
+ fn into_pointer(self) -> NonNull<T> {
+ NonNull::new(Box::into_raw(self)).unwrap()
+ }
+
+ unsafe fn from_pointer(ptr: NonNull<T>) -> Self {
+ unsafe { Box::from_raw(ptr.as_ptr()) }
+ }
+
+ fn as_ref(&self) -> &T {
+ AsRef::as_ref(self)
+ }
+}
+
+impl<T: ?Sized> Wrapper<T> for Ref<T> {
+ fn into_pointer(self) -> NonNull<T> {
+ NonNull::new(Ref::into_raw(self) as _).unwrap()
+ }
+
+ unsafe fn from_pointer(ptr: NonNull<T>) -> Self {
+ // SAFETY: The safety requirements of `from_pointer` satisfy the ones from `Ref::from_raw`.
+ unsafe { Ref::from_raw(ptr.as_ptr() as _) }
+ }
+
+ fn as_ref(&self) -> &T {
+ AsRef::as_ref(self)
+ }
+}
+
+impl<T: ?Sized> Wrapper<T> for &T {
+ fn into_pointer(self) -> NonNull<T> {
+ NonNull::from(self)
+ }
+
+ unsafe fn from_pointer(ptr: NonNull<T>) -> Self {
+ unsafe { &*ptr.as_ptr() }
+ }
+
+ fn as_ref(&self) -> &T {
+ self
+ }
+}
+
+/// A descriptor of wrapped list elements.
+pub trait GetLinksWrapped: GetLinks {
+ /// Specifies which wrapper (e.g., `Box` and `Arc`) wraps the list entries.
+ type Wrapped: Wrapper<Self::EntryType>;
+}
+
+impl<T: ?Sized> GetLinksWrapped for Box<T>
+where
+ Box<T>: GetLinks,
+{
+ type Wrapped = Box<<Box<T> as GetLinks>::EntryType>;
+}
+
+impl<T: GetLinks + ?Sized> GetLinks for Box<T> {
+ type EntryType = T::EntryType;
+ fn get_links(data: &Self::EntryType) -> &Links<Self::EntryType> {
+ <T as GetLinks>::get_links(data)
+ }
+}
+
+impl<T: ?Sized> GetLinksWrapped for Ref<T>
+where
+ Ref<T>: GetLinks,
+{
+ type Wrapped = Ref<<Ref<T> as GetLinks>::EntryType>;
+}
+
+impl<T: GetLinks + ?Sized> GetLinks for Ref<T> {
+ type EntryType = T::EntryType;
+
+ fn get_links(data: &Self::EntryType) -> &Links<Self::EntryType> {
+ <T as GetLinks>::get_links(data)
+ }
+}
+
+/// A linked list.
+///
+/// Elements in the list are wrapped and ownership is transferred to the list while the element is
+/// in the list.
+pub struct List<G: GetLinksWrapped> {
+ list: RawList<G>,
+}
+
+impl<G: GetLinksWrapped> List<G> {
+ /// Constructs a new empty linked list.
+ pub fn new() -> Self {
+ Self {
+ list: RawList::new(),
+ }
+ }
+
+ /// Returns whether the list is empty.
+ pub fn is_empty(&self) -> bool {
+ self.list.is_empty()
+ }
+
+ /// Adds the given object to the end (back) of the list.
+ ///
+ /// It is dropped if it's already on this (or another) list; this can happen for
+ /// reference-counted objects, so dropping means decrementing the reference count.
+ pub fn push_back(&mut self, data: G::Wrapped) {
+ let ptr = data.into_pointer();
+
+ // SAFETY: We took ownership of the entry, so it is safe to insert it.
+ if !unsafe { self.list.push_back(ptr.as_ref()) } {
+ // If insertion failed, rebuild object so that it can be freed.
+ // SAFETY: We just called `into_pointer` above.
+ unsafe { G::Wrapped::from_pointer(ptr) };
+ }
+ }
+
+ /// Inserts the given object after `existing`.
+ ///
+ /// It is dropped if it's already on this (or another) list; this can happen for
+ /// reference-counted objects, so dropping means decrementing the reference count.
+ ///
+ /// # Safety
+ ///
+ /// Callers must ensure that `existing` points to a valid entry that is on the list.
+ pub unsafe fn insert_after(&mut self, existing: NonNull<G::EntryType>, data: G::Wrapped) {
+ let ptr = data.into_pointer();
+ let entry = unsafe { &*existing.as_ptr() };
+ if unsafe { !self.list.insert_after(entry, ptr.as_ref()) } {
+ // If insertion failed, rebuild object so that it can be freed.
+ unsafe { G::Wrapped::from_pointer(ptr) };
+ }
+ }
+
+ /// Removes the given entry.
+ ///
+ /// # Safety
+ ///
+ /// Callers must ensure that `data` is either on this list or in no list. It being on another
+ /// list leads to memory unsafety.
+ pub unsafe fn remove(&mut self, data: &G::Wrapped) -> Option<G::Wrapped> {
+ let entry_ref = Wrapper::as_ref(data);
+ if unsafe { self.list.remove(entry_ref) } {
+ Some(unsafe { G::Wrapped::from_pointer(NonNull::from(entry_ref)) })
+ } else {
+ None
+ }
+ }
+
+ /// Removes the element currently at the front of the list and returns it.
+ ///
+ /// Returns `None` if the list is empty.
+ pub fn pop_front(&mut self) -> Option<G::Wrapped> {
+ let front = self.list.pop_front()?;
+ // SAFETY: Elements on the list were inserted after a call to `into_pointer `.
+ Some(unsafe { G::Wrapped::from_pointer(front) })
+ }
+
+ /// Returns a cursor starting on the first (front) element of the list.
+ pub fn cursor_front(&self) -> Cursor<'_, G> {
+ self.list.cursor_front()
+ }
+
+ /// Returns a mutable cursor starting on the first (front) element of the list.
+ pub fn cursor_front_mut(&mut self) -> CursorMut<'_, G> {
+ CursorMut::new(self.list.cursor_front_mut())
+ }
+}
+
+impl<G: GetLinksWrapped> Default for List<G> {
+ fn default() -> Self {
+ Self::new()
+ }
+}
+
+impl<G: GetLinksWrapped> Drop for List<G> {
+ fn drop(&mut self) {
+ while self.pop_front().is_some() {}
+ }
+}
+
+/// A list cursor that allows traversing a linked list and inspecting & mutating elements.
+pub struct CursorMut<'a, G: GetLinksWrapped> {
+ cursor: raw_list::CursorMut<'a, G>,
+}
+
+impl<'a, G: GetLinksWrapped> CursorMut<'a, G> {
+ fn new(cursor: raw_list::CursorMut<'a, G>) -> Self {
+ Self { cursor }
+ }
+
+ /// Returns the element the cursor is currently positioned on.
+ pub fn current(&mut self) -> Option<&mut G::EntryType> {
+ self.cursor.current()
+ }
+
+ /// Removes the element the cursor is currently positioned on.
+ ///
+ /// After removal, it advances the cursor to the next element.
+ pub fn remove_current(&mut self) -> Option<G::Wrapped> {
+ let ptr = self.cursor.remove_current()?;
+
+ // SAFETY: Elements on the list were inserted after a call to `into_pointer `.
+ Some(unsafe { G::Wrapped::from_pointer(ptr) })
+ }
+
+ /// Returns the element immediately after the one the cursor is positioned on.
+ pub fn peek_next(&mut self) -> Option<&mut G::EntryType> {
+ self.cursor.peek_next()
+ }
+
+ /// Returns the element immediately before the one the cursor is positioned on.
+ pub fn peek_prev(&mut self) -> Option<&mut G::EntryType> {
+ self.cursor.peek_prev()
+ }
+
+ /// Moves the cursor to the next element.
+ pub fn move_next(&mut self) {
+ self.cursor.move_next();
+ }
+}
diff --git a/rust/kernel/miscdev.rs b/rust/kernel/miscdev.rs
new file mode 100644
index 000000000000..65b95d6dba90
--- /dev/null
+++ b/rust/kernel/miscdev.rs
@@ -0,0 +1,290 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Miscellaneous devices.
+//!
+//! C header: [`include/linux/miscdevice.h`](../../../../include/linux/miscdevice.h)
+//!
+//! Reference: <https://www.kernel.org/doc/html/latest/driver-api/misc_devices.html>
+
+use crate::bindings;
+use crate::error::{code::*, Error, Result};
+use crate::file;
+use crate::{device, str::CStr, str::CString, ThisModule};
+use alloc::boxed::Box;
+use core::marker::PhantomPinned;
+use core::{fmt, mem::MaybeUninit, pin::Pin};
+
+/// Options which can be used to configure how a misc device is registered.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::{c_str, device::RawDevice, file, miscdev, prelude::*};
+/// fn example(
+/// reg: Pin<&mut miscdev::Registration<impl file::Operations<OpenData = ()>>>,
+/// parent: &dyn RawDevice,
+/// ) -> Result {
+/// miscdev::Options::new()
+/// .mode(0o600)
+/// .minor(10)
+/// .parent(parent)
+/// .register(reg, fmt!("sample"), ())
+/// }
+/// ```
+#[derive(Default)]
+pub struct Options<'a> {
+ minor: Option<i32>,
+ mode: Option<u16>,
+ parent: Option<&'a dyn device::RawDevice>,
+}
+
+impl<'a> Options<'a> {
+ /// Creates new [`Options`] instance with the required fields.
+ pub const fn new() -> Self {
+ Self {
+ minor: None,
+ mode: None,
+ parent: None,
+ }
+ }
+
+ /// Sets the minor device number.
+ pub const fn minor(&mut self, v: i32) -> &mut Self {
+ self.minor = Some(v);
+ self
+ }
+
+ /// Sets the device mode.
+ ///
+ /// This is usually an octal number and describes who can perform read/write/execute operations
+ /// on the device.
+ pub const fn mode(&mut self, m: u16) -> &mut Self {
+ self.mode = Some(m);
+ self
+ }
+
+ /// Sets the device parent.
+ pub const fn parent(&mut self, p: &'a dyn device::RawDevice) -> &mut Self {
+ self.parent = Some(p);
+ self
+ }
+
+ /// Registers a misc device using the configured options.
+ pub fn register<T: file::Operations>(
+ &self,
+ reg: Pin<&mut Registration<T>>,
+ name: fmt::Arguments<'_>,
+ open_data: T::OpenData,
+ ) -> Result {
+ reg.register_with_options(name, open_data, self)
+ }
+
+ /// Allocates a new registration of a misc device and completes the registration with the
+ /// configured options.
+ pub fn register_new<T: file::Operations>(
+ &self,
+ name: fmt::Arguments<'_>,
+ open_data: T::OpenData,
+ ) -> Result<Pin<Box<Registration<T>>>> {
+ let mut r = Pin::from(Box::try_new(Registration::new())?);
+ self.register(r.as_mut(), name, open_data)?;
+ Ok(r)
+ }
+}
+
+/// A registration of a miscellaneous device.
+///
+/// # Invariants
+///
+/// `Context` is always initialised when `registered` is `true`, and not initialised otherwise.
+pub struct Registration<T: file::Operations> {
+ registered: bool,
+ mdev: bindings::miscdevice,
+ name: Option<CString>,
+ _pin: PhantomPinned,
+
+ /// Context initialised on construction and made available to all file instances on
+ /// [`file::Operations::open`].
+ open_data: MaybeUninit<T::OpenData>,
+}
+
+impl<T: file::Operations> Registration<T> {
+ /// Creates a new [`Registration`] but does not register it yet.
+ ///
+ /// It is allowed to move.
+ pub fn new() -> Self {
+ // INVARIANT: `registered` is `false` and `open_data` is not initialised.
+ Self {
+ registered: false,
+ mdev: bindings::miscdevice::default(),
+ name: None,
+ _pin: PhantomPinned,
+ open_data: MaybeUninit::uninit(),
+ }
+ }
+
+ /// Registers a miscellaneous device.
+ ///
+ /// Returns a pinned heap-allocated representation of the registration.
+ pub fn new_pinned(name: fmt::Arguments<'_>, open_data: T::OpenData) -> Result<Pin<Box<Self>>> {
+ Options::new().register_new(name, open_data)
+ }
+
+ /// Registers a miscellaneous device with the rest of the kernel.
+ ///
+ /// It must be pinned because the memory block that represents the registration is
+ /// self-referential.
+ pub fn register(
+ self: Pin<&mut Self>,
+ name: fmt::Arguments<'_>,
+ open_data: T::OpenData,
+ ) -> Result {
+ Options::new().register(self, name, open_data)
+ }
+
+ /// Registers a miscellaneous device with the rest of the kernel. Additional optional settings
+ /// are provided via the `opts` parameter.
+ ///
+ /// It must be pinned because the memory block that represents the registration is
+ /// self-referential.
+ pub fn register_with_options(
+ self: Pin<&mut Self>,
+ name: fmt::Arguments<'_>,
+ open_data: T::OpenData,
+ opts: &Options<'_>,
+ ) -> Result {
+ // SAFETY: We must ensure that we never move out of `this`.
+ let this = unsafe { self.get_unchecked_mut() };
+ if this.registered {
+ // Already registered.
+ return Err(EINVAL);
+ }
+
+ let name = CString::try_from_fmt(name)?;
+
+ // SAFETY: The adapter is compatible with `misc_register`.
+ this.mdev.fops = unsafe { file::OperationsVtable::<Self, T>::build() };
+ this.mdev.name = name.as_char_ptr();
+ this.mdev.minor = opts.minor.unwrap_or(bindings::MISC_DYNAMIC_MINOR as i32);
+ this.mdev.mode = opts.mode.unwrap_or(0);
+ this.mdev.parent = opts
+ .parent
+ .map_or(core::ptr::null_mut(), |p| p.raw_device());
+
+ // We write to `open_data` here because as soon as `misc_register` succeeds, the file can be
+ // opened, so we need `open_data` configured ahead of time.
+ //
+ // INVARIANT: `registered` is set to `true`, but `open_data` is also initialised.
+ this.registered = true;
+ this.open_data.write(open_data);
+
+ let ret = unsafe { bindings::misc_register(&mut this.mdev) };
+ if ret < 0 {
+ // INVARIANT: `registered` is set back to `false` and the `open_data` is destructued.
+ this.registered = false;
+ // SAFETY: `open_data` was initialised a few lines above.
+ unsafe { this.open_data.assume_init_drop() };
+ return Err(Error::from_kernel_errno(ret));
+ }
+
+ this.name = Some(name);
+
+ Ok(())
+ }
+}
+
+impl<T: file::Operations> Default for Registration<T> {
+ fn default() -> Self {
+ Self::new()
+ }
+}
+
+impl<T: file::Operations> file::OpenAdapter<T::OpenData> for Registration<T> {
+ unsafe fn convert(
+ _inode: *mut bindings::inode,
+ file: *mut bindings::file,
+ ) -> *const T::OpenData {
+ // SAFETY: The caller must guarantee that `file` is valid.
+ let reg = crate::container_of!(unsafe { (*file).private_data }, Self, mdev);
+
+ // SAFETY: This function is only called while the misc device is still registered, so the
+ // registration must be valid. Additionally, the type invariants guarantee that while the
+ // miscdev is registered, `open_data` is initialised.
+ unsafe { (*reg).open_data.as_ptr() }
+ }
+}
+
+// SAFETY: The only method is `register()`, which requires a (pinned) mutable `Registration`, so it
+// is safe to pass `&Registration` to multiple threads because it offers no interior mutability.
+unsafe impl<T: file::Operations> Sync for Registration<T> {}
+
+// SAFETY: All functions work from any thread. So as long as the `Registration::open_data` is
+// `Send`, so is `Registration<T>`.
+unsafe impl<T: file::Operations> Send for Registration<T> where T::OpenData: Send {}
+
+impl<T: file::Operations> Drop for Registration<T> {
+ /// Removes the registration from the kernel if it has completed successfully before.
+ fn drop(&mut self) {
+ if self.registered {
+ // SAFETY: `registered` being `true` indicates that a previous call to `misc_register`
+ // succeeded.
+ unsafe { bindings::misc_deregister(&mut self.mdev) };
+
+ // SAFETY: The type invariant guarantees that `open_data` is initialised when
+ // `registered` is `true`.
+ unsafe { self.open_data.assume_init_drop() };
+ }
+ }
+}
+
+/// Kernel module that exposes a single miscdev device implemented by `T`.
+pub struct Module<T: file::Operations<OpenData = ()>> {
+ _dev: Pin<Box<Registration<T>>>,
+}
+
+impl<T: file::Operations<OpenData = ()>> crate::Module for Module<T> {
+ fn init(name: &'static CStr, _module: &'static ThisModule) -> Result<Self> {
+ Ok(Self {
+ _dev: Registration::new_pinned(crate::fmt!("{name}"), ())?,
+ })
+ }
+}
+
+/// Declares a kernel module that exposes a single misc device.
+///
+/// The `type` argument should be a type which implements the [`FileOpener`] trait. Also accepts
+/// various forms of kernel metadata.
+///
+/// C header: [`include/linux/moduleparam.h`](../../../include/linux/moduleparam.h)
+///
+/// [`FileOpener`]: ../kernel/file_operations/trait.FileOpener.html
+///
+/// # Examples
+///
+/// ```ignore
+/// use kernel::prelude::*;
+///
+/// module_misc_device! {
+/// type: MyFile,
+/// name: b"my_miscdev_kernel_module",
+/// author: b"Rust for Linux Contributors",
+/// description: b"My very own misc device kernel module!",
+/// license: b"GPL",
+/// }
+///
+/// #[derive(Default)]
+/// struct MyFile;
+///
+/// #[vtable]
+/// impl kernel::file::Operations for MyFile {}
+/// ```
+#[macro_export]
+macro_rules! module_misc_device {
+ (type: $type:ty, $($f:tt)*) => {
+ type ModuleType = kernel::miscdev::Module<$type>;
+ module! {
+ type: ModuleType,
+ $($f)*
+ }
+ }
+}
diff --git a/rust/kernel/mm.rs b/rust/kernel/mm.rs
new file mode 100644
index 000000000000..8a69c69dddd9
--- /dev/null
+++ b/rust/kernel/mm.rs
@@ -0,0 +1,149 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Memory management.
+//!
+//! C header: [`include/linux/mm.h`](../../../../include/linux/mm.h)
+
+use crate::{bindings, pages, to_result, Result};
+
+/// Virtual memory.
+pub mod virt {
+ use super::*;
+
+ /// A wrapper for the kernel's `struct vm_area_struct`.
+ ///
+ /// It represents an area of virtual memory.
+ ///
+ /// # Invariants
+ ///
+ /// `vma` is always non-null and valid.
+ pub struct Area {
+ vma: *mut bindings::vm_area_struct,
+ }
+
+ impl Area {
+ /// Creates a new instance of a virtual memory area.
+ ///
+ /// # Safety
+ ///
+ /// Callers must ensure that `vma` is non-null and valid for the duration of the new area's
+ /// lifetime.
+ pub(crate) unsafe fn from_ptr(vma: *mut bindings::vm_area_struct) -> Self {
+ // INVARIANTS: The safety requirements guarantee the invariants.
+ Self { vma }
+ }
+
+ /// Returns the flags associated with the virtual memory area.
+ ///
+ /// The possible flags are a combination of the constants in [`flags`].
+ pub fn flags(&self) -> usize {
+ // SAFETY: `self.vma` is valid by the type invariants.
+ unsafe { (*self.vma).vm_flags as _ }
+ }
+
+ /// Sets the flags associated with the virtual memory area.
+ ///
+ /// The possible flags are a combination of the constants in [`flags`].
+ pub fn set_flags(&mut self, flags: usize) {
+ // SAFETY: `self.vma` is valid by the type invariants.
+ unsafe { (*self.vma).vm_flags = flags as _ };
+ }
+
+ /// Returns the start address of the virtual memory area.
+ pub fn start(&self) -> usize {
+ // SAFETY: `self.vma` is valid by the type invariants.
+ unsafe { (*self.vma).vm_start as _ }
+ }
+
+ /// Returns the end address of the virtual memory area.
+ pub fn end(&self) -> usize {
+ // SAFETY: `self.vma` is valid by the type invariants.
+ unsafe { (*self.vma).vm_end as _ }
+ }
+
+ /// Maps a single page at the given address within the virtual memory area.
+ pub fn insert_page(&mut self, address: usize, page: &pages::Pages<0>) -> Result {
+ // SAFETY: The page is guaranteed to be order 0 by the type system. The range of
+ // `address` is already checked by `vm_insert_page`. `self.vma` and `page.pages` are
+ // guaranteed by their repective type invariants to be valid.
+ to_result(unsafe { bindings::vm_insert_page(self.vma, address as _, page.pages) })
+ }
+ }
+
+ /// Container for [`Area`] flags.
+ pub mod flags {
+ use crate::bindings;
+
+ /// No flags are set.
+ pub const NONE: usize = bindings::VM_NONE as _;
+
+ /// Mapping allows reads.
+ pub const READ: usize = bindings::VM_READ as _;
+
+ /// Mapping allows writes.
+ pub const WRITE: usize = bindings::VM_WRITE as _;
+
+ /// Mapping allows execution.
+ pub const EXEC: usize = bindings::VM_EXEC as _;
+
+ /// Mapping is shared.
+ pub const SHARED: usize = bindings::VM_SHARED as _;
+
+ /// Mapping may be updated to allow reads.
+ pub const MAYREAD: usize = bindings::VM_MAYREAD as _;
+
+ /// Mapping may be updated to allow writes.
+ pub const MAYWRITE: usize = bindings::VM_MAYWRITE as _;
+
+ /// Mapping may be updated to allow execution.
+ pub const MAYEXEC: usize = bindings::VM_MAYEXEC as _;
+
+ /// Mapping may be updated to be shared.
+ pub const MAYSHARE: usize = bindings::VM_MAYSHARE as _;
+
+ /// Do not copy this vma on fork.
+ pub const DONTCOPY: usize = bindings::VM_DONTCOPY as _;
+
+ /// Cannot expand with mremap().
+ pub const DONTEXPAND: usize = bindings::VM_DONTEXPAND as _;
+
+ /// Lock the pages covered when they are faulted in.
+ pub const LOCKONFAULT: usize = bindings::VM_LOCKONFAULT as _;
+
+ /// Is a VM accounted object.
+ pub const ACCOUNT: usize = bindings::VM_ACCOUNT as _;
+
+ /// should the VM suppress accounting.
+ pub const NORESERVE: usize = bindings::VM_NORESERVE as _;
+
+ /// Huge TLB Page VM.
+ pub const HUGETLB: usize = bindings::VM_HUGETLB as _;
+
+ /// Synchronous page faults.
+ pub const SYNC: usize = bindings::VM_SYNC as _;
+
+ /// Architecture-specific flag.
+ pub const ARCH_1: usize = bindings::VM_ARCH_1 as _;
+
+ /// Wipe VMA contents in child..
+ pub const WIPEONFORK: usize = bindings::VM_WIPEONFORK as _;
+
+ /// Do not include in the core dump.
+ pub const DONTDUMP: usize = bindings::VM_DONTDUMP as _;
+
+ /// Not soft dirty clean area.
+ pub const SOFTDIRTY: usize = bindings::VM_SOFTDIRTY as _;
+
+ /// Can contain "struct page" and pure PFN pages.
+ pub const MIXEDMAP: usize = bindings::VM_MIXEDMAP as _;
+
+ /// MADV_HUGEPAGE marked this vma.
+ pub const HUGEPAGE: usize = bindings::VM_HUGEPAGE as _;
+
+ /// MADV_NOHUGEPAGE marked this vma.
+ pub const NOHUGEPAGE: usize = bindings::VM_NOHUGEPAGE as _;
+
+ /// KSM may merge identical pages.
+ pub const MERGEABLE: usize = bindings::VM_MERGEABLE as _;
+ }
+}
diff --git a/rust/kernel/module_param.rs b/rust/kernel/module_param.rs
new file mode 100644
index 000000000000..6df38c78c65c
--- /dev/null
+++ b/rust/kernel/module_param.rs
@@ -0,0 +1,499 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Types for module parameters.
+//!
+//! C header: [`include/linux/moduleparam.h`](../../../include/linux/moduleparam.h)
+
+use crate::error::{code::*, from_kernel_result};
+use crate::str::{CStr, Formatter};
+use core::fmt::Write;
+
+/// Types that can be used for module parameters.
+///
+/// Note that displaying the type in `sysfs` will fail if
+/// [`alloc::string::ToString::to_string`] (as implemented through the
+/// [`core::fmt::Display`] trait) writes more than [`PAGE_SIZE`]
+/// bytes (including an additional null terminator).
+///
+/// [`PAGE_SIZE`]: `crate::PAGE_SIZE`
+pub trait ModuleParam: core::fmt::Display + core::marker::Sized {
+ /// The `ModuleParam` will be used by the kernel module through this type.
+ ///
+ /// This may differ from `Self` if, for example, `Self` needs to track
+ /// ownership without exposing it or allocate extra space for other possible
+ /// parameter values. See [`StringParam`] or [`ArrayParam`] for examples.
+ type Value: ?Sized;
+
+ /// Whether the parameter is allowed to be set without an argument.
+ ///
+ /// Setting this to `true` allows the parameter to be passed without an
+ /// argument (e.g. just `module.param` instead of `module.param=foo`).
+ const NOARG_ALLOWED: bool;
+
+ /// Convert a parameter argument into the parameter value.
+ ///
+ /// `None` should be returned when parsing of the argument fails.
+ /// `arg == None` indicates that the parameter was passed without an
+ /// argument. If `NOARG_ALLOWED` is set to `false` then `arg` is guaranteed
+ /// to always be `Some(_)`.
+ ///
+ /// Parameters passed at boot time will be set before [`kmalloc`] is
+ /// available (even if the module is loaded at a later time). However, in
+ /// this case, the argument buffer will be valid for the entire lifetime of
+ /// the kernel. So implementations of this method which need to allocate
+ /// should first check that the allocator is available (with
+ /// [`crate::bindings::slab_is_available`]) and when it is not available
+ /// provide an alternative implementation which doesn't allocate. In cases
+ /// where the allocator is not available it is safe to save references to
+ /// `arg` in `Self`, but in other cases a copy should be made.
+ ///
+ /// [`kmalloc`]: ../../../include/linux/slab.h
+ fn try_from_param_arg(arg: Option<&'static [u8]>) -> Option<Self>;
+
+ /// Get the current value of the parameter for use in the kernel module.
+ ///
+ /// This function should not be used directly. Instead use the wrapper
+ /// `read` which will be generated by [`macros::module`].
+ fn value(&self) -> &Self::Value;
+
+ /// Set the module parameter from a string.
+ ///
+ /// Used to set the parameter value when loading the module or when set
+ /// through `sysfs`.
+ ///
+ /// # Safety
+ ///
+ /// If `val` is non-null then it must point to a valid null-terminated
+ /// string. The `arg` field of `param` must be an instance of `Self`.
+ unsafe extern "C" fn set_param(
+ val: *const core::ffi::c_char,
+ param: *const crate::bindings::kernel_param,
+ ) -> core::ffi::c_int {
+ let arg = if val.is_null() {
+ None
+ } else {
+ Some(unsafe { CStr::from_char_ptr(val).as_bytes() })
+ };
+ match Self::try_from_param_arg(arg) {
+ Some(new_value) => {
+ let old_value = unsafe { (*param).__bindgen_anon_1.arg as *mut Self };
+ let _ = unsafe { core::ptr::replace(old_value, new_value) };
+ 0
+ }
+ None => EINVAL.to_kernel_errno(),
+ }
+ }
+
+ /// Write a string representation of the current parameter value to `buf`.
+ ///
+ /// Used for displaying the current parameter value in `sysfs`.
+ ///
+ /// # Safety
+ ///
+ /// `buf` must be a buffer of length at least `kernel::PAGE_SIZE` that is
+ /// writeable. The `arg` field of `param` must be an instance of `Self`.
+ unsafe extern "C" fn get_param(
+ buf: *mut core::ffi::c_char,
+ param: *const crate::bindings::kernel_param,
+ ) -> core::ffi::c_int {
+ from_kernel_result! {
+ // SAFETY: The C contracts guarantees that the buffer is at least `PAGE_SIZE` bytes.
+ let mut f = unsafe { Formatter::from_buffer(buf.cast(), crate::PAGE_SIZE) };
+ unsafe { write!(f, "{}\0", *((*param).__bindgen_anon_1.arg as *mut Self)) }?;
+ Ok(f.bytes_written().try_into()?)
+ }
+ }
+
+ /// Drop the parameter.
+ ///
+ /// Called when unloading a module.
+ ///
+ /// # Safety
+ ///
+ /// The `arg` field of `param` must be an instance of `Self`.
+ unsafe extern "C" fn free(arg: *mut core::ffi::c_void) {
+ unsafe { core::ptr::drop_in_place(arg as *mut Self) };
+ }
+}
+
+/// Trait for parsing integers.
+///
+/// Strings beginning with `0x`, `0o`, or `0b` are parsed as hex, octal, or
+/// binary respectively. Strings beginning with `0` otherwise are parsed as
+/// octal. Anything else is parsed as decimal. A leading `+` or `-` is also
+/// permitted. Any string parsed by [`kstrtol()`] or [`kstrtoul()`] will be
+/// successfully parsed.
+///
+/// [`kstrtol()`]: https://www.kernel.org/doc/html/latest/core-api/kernel-api.html#c.kstrtol
+/// [`kstrtoul()`]: https://www.kernel.org/doc/html/latest/core-api/kernel-api.html#c.kstrtoul
+trait ParseInt: Sized {
+ fn from_str_radix(src: &str, radix: u32) -> Result<Self, core::num::ParseIntError>;
+ fn checked_neg(self) -> Option<Self>;
+
+ fn from_str_unsigned(src: &str) -> Result<Self, core::num::ParseIntError> {
+ let (radix, digits) = if let Some(n) = src.strip_prefix("0x") {
+ (16, n)
+ } else if let Some(n) = src.strip_prefix("0X") {
+ (16, n)
+ } else if let Some(n) = src.strip_prefix("0o") {
+ (8, n)
+ } else if let Some(n) = src.strip_prefix("0O") {
+ (8, n)
+ } else if let Some(n) = src.strip_prefix("0b") {
+ (2, n)
+ } else if let Some(n) = src.strip_prefix("0B") {
+ (2, n)
+ } else if src.starts_with('0') {
+ (8, src)
+ } else {
+ (10, src)
+ };
+ Self::from_str_radix(digits, radix)
+ }
+
+ fn from_str(src: &str) -> Option<Self> {
+ match src.bytes().next() {
+ None => None,
+ Some(b'-') => Self::from_str_unsigned(&src[1..]).ok()?.checked_neg(),
+ Some(b'+') => Some(Self::from_str_unsigned(&src[1..]).ok()?),
+ Some(_) => Some(Self::from_str_unsigned(src).ok()?),
+ }
+ }
+}
+
+macro_rules! impl_parse_int {
+ ($ty:ident) => {
+ impl ParseInt for $ty {
+ fn from_str_radix(src: &str, radix: u32) -> Result<Self, core::num::ParseIntError> {
+ $ty::from_str_radix(src, radix)
+ }
+
+ fn checked_neg(self) -> Option<Self> {
+ self.checked_neg()
+ }
+ }
+ };
+}
+
+impl_parse_int!(i8);
+impl_parse_int!(u8);
+impl_parse_int!(i16);
+impl_parse_int!(u16);
+impl_parse_int!(i32);
+impl_parse_int!(u32);
+impl_parse_int!(i64);
+impl_parse_int!(u64);
+impl_parse_int!(isize);
+impl_parse_int!(usize);
+
+macro_rules! impl_module_param {
+ ($ty:ident) => {
+ impl ModuleParam for $ty {
+ type Value = $ty;
+
+ const NOARG_ALLOWED: bool = false;
+
+ fn try_from_param_arg(arg: Option<&'static [u8]>) -> Option<Self> {
+ let bytes = arg?;
+ let utf8 = core::str::from_utf8(bytes).ok()?;
+ <$ty as crate::module_param::ParseInt>::from_str(utf8)
+ }
+
+ fn value(&self) -> &Self::Value {
+ self
+ }
+ }
+ };
+}
+
+#[doc(hidden)]
+#[macro_export]
+/// Generate a static [`kernel_param_ops`](../../../include/linux/moduleparam.h) struct.
+///
+/// # Examples
+///
+/// ```ignore
+/// make_param_ops!(
+/// /// Documentation for new param ops.
+/// PARAM_OPS_MYTYPE, // Name for the static.
+/// MyType // A type which implements [`ModuleParam`].
+/// );
+/// ```
+macro_rules! make_param_ops {
+ ($ops:ident, $ty:ty) => {
+ $crate::make_param_ops!(
+ #[doc=""]
+ $ops,
+ $ty
+ );
+ };
+ ($(#[$meta:meta])* $ops:ident, $ty:ty) => {
+ $(#[$meta])*
+ ///
+ /// Static [`kernel_param_ops`](../../../include/linux/moduleparam.h)
+ /// struct generated by [`make_param_ops`].
+ pub static $ops: $crate::bindings::kernel_param_ops = $crate::bindings::kernel_param_ops {
+ flags: if <$ty as $crate::module_param::ModuleParam>::NOARG_ALLOWED {
+ $crate::bindings::KERNEL_PARAM_OPS_FL_NOARG
+ } else {
+ 0
+ },
+ set: Some(<$ty as $crate::module_param::ModuleParam>::set_param),
+ get: Some(<$ty as $crate::module_param::ModuleParam>::get_param),
+ free: Some(<$ty as $crate::module_param::ModuleParam>::free),
+ };
+ };
+}
+
+impl_module_param!(i8);
+impl_module_param!(u8);
+impl_module_param!(i16);
+impl_module_param!(u16);
+impl_module_param!(i32);
+impl_module_param!(u32);
+impl_module_param!(i64);
+impl_module_param!(u64);
+impl_module_param!(isize);
+impl_module_param!(usize);
+
+make_param_ops!(
+ /// Rust implementation of [`kernel_param_ops`](../../../include/linux/moduleparam.h)
+ /// for [`i8`].
+ PARAM_OPS_I8,
+ i8
+);
+make_param_ops!(
+ /// Rust implementation of [`kernel_param_ops`](../../../include/linux/moduleparam.h)
+ /// for [`u8`].
+ PARAM_OPS_U8,
+ u8
+);
+make_param_ops!(
+ /// Rust implementation of [`kernel_param_ops`](../../../include/linux/moduleparam.h)
+ /// for [`i16`].
+ PARAM_OPS_I16,
+ i16
+);
+make_param_ops!(
+ /// Rust implementation of [`kernel_param_ops`](../../../include/linux/moduleparam.h)
+ /// for [`u16`].
+ PARAM_OPS_U16,
+ u16
+);
+make_param_ops!(
+ /// Rust implementation of [`kernel_param_ops`](../../../include/linux/moduleparam.h)
+ /// for [`i32`].
+ PARAM_OPS_I32,
+ i32
+);
+make_param_ops!(
+ /// Rust implementation of [`kernel_param_ops`](../../../include/linux/moduleparam.h)
+ /// for [`u32`].
+ PARAM_OPS_U32,
+ u32
+);
+make_param_ops!(
+ /// Rust implementation of [`kernel_param_ops`](../../../include/linux/moduleparam.h)
+ /// for [`i64`].
+ PARAM_OPS_I64,
+ i64
+);
+make_param_ops!(
+ /// Rust implementation of [`kernel_param_ops`](../../../include/linux/moduleparam.h)
+ /// for [`u64`].
+ PARAM_OPS_U64,
+ u64
+);
+make_param_ops!(
+ /// Rust implementation of [`kernel_param_ops`](../../../include/linux/moduleparam.h)
+ /// for [`isize`].
+ PARAM_OPS_ISIZE,
+ isize
+);
+make_param_ops!(
+ /// Rust implementation of [`kernel_param_ops`](../../../include/linux/moduleparam.h)
+ /// for [`usize`].
+ PARAM_OPS_USIZE,
+ usize
+);
+
+impl ModuleParam for bool {
+ type Value = bool;
+
+ const NOARG_ALLOWED: bool = true;
+
+ fn try_from_param_arg(arg: Option<&'static [u8]>) -> Option<Self> {
+ match arg {
+ None => Some(true),
+ Some(b"y") | Some(b"Y") | Some(b"1") | Some(b"true") => Some(true),
+ Some(b"n") | Some(b"N") | Some(b"0") | Some(b"false") => Some(false),
+ _ => None,
+ }
+ }
+
+ fn value(&self) -> &Self::Value {
+ self
+ }
+}
+
+make_param_ops!(
+ /// Rust implementation of [`kernel_param_ops`](../../../include/linux/moduleparam.h)
+ /// for [`bool`].
+ PARAM_OPS_BOOL,
+ bool
+);
+
+/// An array of at __most__ `N` values.
+///
+/// # Invariant
+///
+/// The first `self.used` elements of `self.values` are initialized.
+pub struct ArrayParam<T, const N: usize> {
+ values: [core::mem::MaybeUninit<T>; N],
+ used: usize,
+}
+
+impl<T, const N: usize> ArrayParam<T, { N }> {
+ fn values(&self) -> &[T] {
+ // SAFETY: The invariant maintained by `ArrayParam` allows us to cast
+ // the first `self.used` elements to `T`.
+ unsafe {
+ &*(&self.values[0..self.used] as *const [core::mem::MaybeUninit<T>] as *const [T])
+ }
+ }
+}
+
+impl<T: Copy, const N: usize> ArrayParam<T, { N }> {
+ const fn new() -> Self {
+ // INVARIANT: The first `self.used` elements of `self.values` are
+ // initialized.
+ ArrayParam {
+ values: [core::mem::MaybeUninit::uninit(); N],
+ used: 0,
+ }
+ }
+
+ const fn push(&mut self, val: T) {
+ if self.used < N {
+ // INVARIANT: The first `self.used` elements of `self.values` are
+ // initialized.
+ self.values[self.used] = core::mem::MaybeUninit::new(val);
+ self.used += 1;
+ }
+ }
+
+ /// Create an instance of `ArrayParam` initialized with `vals`.
+ ///
+ /// This function is only meant to be used in the [`module::module`] macro.
+ pub const fn create(vals: &[T]) -> Self {
+ let mut result = ArrayParam::new();
+ let mut i = 0;
+ while i < vals.len() {
+ result.push(vals[i]);
+ i += 1;
+ }
+ result
+ }
+}
+
+impl<T: core::fmt::Display, const N: usize> core::fmt::Display for ArrayParam<T, { N }> {
+ fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+ for val in self.values() {
+ write!(f, "{},", val)?;
+ }
+ Ok(())
+ }
+}
+
+impl<T: Copy + core::fmt::Display + ModuleParam, const N: usize> ModuleParam
+ for ArrayParam<T, { N }>
+{
+ type Value = [T];
+
+ const NOARG_ALLOWED: bool = false;
+
+ fn try_from_param_arg(arg: Option<&'static [u8]>) -> Option<Self> {
+ arg.and_then(|args| {
+ let mut result = Self::new();
+ for arg in args.split(|b| *b == b',') {
+ result.push(T::try_from_param_arg(Some(arg))?);
+ }
+ Some(result)
+ })
+ }
+
+ fn value(&self) -> &Self::Value {
+ self.values()
+ }
+}
+
+/// A C-style string parameter.
+///
+/// The Rust version of the [`charp`] parameter. This type is meant to be
+/// used by the [`macros::module`] macro, not handled directly. Instead use the
+/// `read` method generated by that macro.
+///
+/// [`charp`]: ../../../include/linux/moduleparam.h
+pub enum StringParam {
+ /// A borrowed parameter value.
+ ///
+ /// Either the default value (which is static in the module) or borrowed
+ /// from the original argument buffer used to set the value.
+ Ref(&'static [u8]),
+
+ /// A value that was allocated when the parameter was set.
+ ///
+ /// The value needs to be freed when the parameter is reset or the module is
+ /// unloaded.
+ Owned(alloc::vec::Vec<u8>),
+}
+
+impl StringParam {
+ fn bytes(&self) -> &[u8] {
+ match self {
+ StringParam::Ref(bytes) => *bytes,
+ StringParam::Owned(vec) => &vec[..],
+ }
+ }
+}
+
+impl core::fmt::Display for StringParam {
+ fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+ let bytes = self.bytes();
+ match core::str::from_utf8(bytes) {
+ Ok(utf8) => write!(f, "{}", utf8),
+ Err(_) => write!(f, "{:?}", bytes),
+ }
+ }
+}
+
+impl ModuleParam for StringParam {
+ type Value = [u8];
+
+ const NOARG_ALLOWED: bool = false;
+
+ fn try_from_param_arg(arg: Option<&'static [u8]>) -> Option<Self> {
+ // SAFETY: It is always safe to call [`slab_is_available`](../../../include/linux/slab.h).
+ let slab_available = unsafe { crate::bindings::slab_is_available() };
+ arg.and_then(|arg| {
+ if slab_available {
+ let mut vec = alloc::vec::Vec::new();
+ vec.try_extend_from_slice(arg).ok()?;
+ Some(StringParam::Owned(vec))
+ } else {
+ Some(StringParam::Ref(arg))
+ }
+ })
+ }
+
+ fn value(&self) -> &Self::Value {
+ self.bytes()
+ }
+}
+
+make_param_ops!(
+ /// Rust implementation of [`kernel_param_ops`](../../../include/linux/moduleparam.h)
+ /// for [`StringParam`].
+ PARAM_OPS_STR,
+ StringParam
+);
diff --git a/rust/kernel/net.rs b/rust/kernel/net.rs
new file mode 100644
index 000000000000..0115f3a35cd0
--- /dev/null
+++ b/rust/kernel/net.rs
@@ -0,0 +1,392 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Networking core.
+//!
+//! C headers: [`include/net/net_namespace.h`](../../../../include/linux/net/net_namespace.h),
+//! [`include/linux/netdevice.h`](../../../../include/linux/netdevice.h),
+//! [`include/linux/skbuff.h`](../../../../include/linux/skbuff.h).
+
+use crate::{bindings, str::CStr, to_result, ARef, AlwaysRefCounted, Error, Result};
+use core::{cell::UnsafeCell, ptr::NonNull};
+
+#[cfg(CONFIG_NETFILTER)]
+pub mod filter;
+
+/// Wraps the kernel's `struct net_device`.
+#[repr(transparent)]
+pub struct Device(UnsafeCell<bindings::net_device>);
+
+// SAFETY: Instances of `Device` are created on the C side. They are always refcounted.
+unsafe impl AlwaysRefCounted for Device {
+ fn inc_ref(&self) {
+ // SAFETY: The existence of a shared reference means that the refcount is nonzero.
+ unsafe { bindings::dev_hold(self.0.get()) };
+ }
+
+ unsafe fn dec_ref(obj: core::ptr::NonNull<Self>) {
+ // SAFETY: The safety requirements guarantee that the refcount is nonzero.
+ unsafe { bindings::dev_put(obj.cast().as_ptr()) };
+ }
+}
+
+/// Wraps the kernel's `struct net`.
+#[repr(transparent)]
+pub struct Namespace(UnsafeCell<bindings::net>);
+
+impl Namespace {
+ /// Finds a network device with the given name in the namespace.
+ pub fn dev_get_by_name(&self, name: &CStr) -> Option<ARef<Device>> {
+ // SAFETY: The existence of a shared reference guarantees the refcount is nonzero.
+ let ptr =
+ NonNull::new(unsafe { bindings::dev_get_by_name(self.0.get(), name.as_char_ptr()) })?;
+ Some(unsafe { ARef::from_raw(ptr.cast()) })
+ }
+}
+
+// SAFETY: Instances of `Namespace` are created on the C side. They are always refcounted.
+unsafe impl AlwaysRefCounted for Namespace {
+ fn inc_ref(&self) {
+ // SAFETY: The existence of a shared reference means that the refcount is nonzero.
+ unsafe { bindings::get_net(self.0.get()) };
+ }
+
+ unsafe fn dec_ref(obj: core::ptr::NonNull<Self>) {
+ // SAFETY: The safety requirements guarantee that the refcount is nonzero.
+ unsafe { bindings::put_net(obj.cast().as_ptr()) };
+ }
+}
+
+/// Returns the network namespace for the `init` process.
+pub fn init_ns() -> &'static Namespace {
+ unsafe { &*core::ptr::addr_of!(bindings::init_net).cast() }
+}
+
+/// Wraps the kernel's `struct sk_buff`.
+#[repr(transparent)]
+pub struct SkBuff(UnsafeCell<bindings::sk_buff>);
+
+impl SkBuff {
+ /// Creates a reference to an [`SkBuff`] from a valid pointer.
+ ///
+ /// # Safety
+ ///
+ /// The caller must ensure that `ptr` is valid and remains valid for the lifetime of the
+ /// returned [`SkBuff`] instance.
+ pub unsafe fn from_ptr<'a>(ptr: *const bindings::sk_buff) -> &'a SkBuff {
+ // SAFETY: The safety requirements guarantee the validity of the dereference, while the
+ // `SkBuff` type being transparent makes the cast ok.
+ unsafe { &*ptr.cast() }
+ }
+
+ /// Returns the remaining data in the buffer's first segment.
+ pub fn head_data(&self) -> &[u8] {
+ // SAFETY: The existence of a shared reference means that the refcount is nonzero.
+ let headlen = unsafe { bindings::skb_headlen(self.0.get()) };
+ let len = headlen.try_into().unwrap_or(usize::MAX);
+ // SAFETY: The existence of a shared reference means `self.0` is valid.
+ let data = unsafe { core::ptr::addr_of!((*self.0.get()).data).read() };
+ // SAFETY: The `struct sk_buff` conventions guarantee that at least `skb_headlen(skb)` bytes
+ // are valid from `skb->data`.
+ unsafe { core::slice::from_raw_parts(data, len) }
+ }
+
+ /// Returns the total length of the data (in all segments) in the skb.
+ #[allow(clippy::len_without_is_empty)]
+ pub fn len(&self) -> u32 {
+ // SAFETY: The existence of a shared reference means `self.0` is valid.
+ unsafe { core::ptr::addr_of!((*self.0.get()).len).read() }
+ }
+}
+
+// SAFETY: Instances of `SkBuff` are created on the C side. They are always refcounted.
+unsafe impl AlwaysRefCounted for SkBuff {
+ fn inc_ref(&self) {
+ // SAFETY: The existence of a shared reference means that the refcount is nonzero.
+ unsafe { bindings::skb_get(self.0.get()) };
+ }
+
+ unsafe fn dec_ref(obj: core::ptr::NonNull<Self>) {
+ // SAFETY: The safety requirements guarantee that the refcount is nonzero.
+ unsafe {
+ bindings::kfree_skb_reason(
+ obj.cast().as_ptr(),
+ bindings::skb_drop_reason_SKB_DROP_REASON_NOT_SPECIFIED,
+ )
+ };
+ }
+}
+
+/// An IPv4 address.
+///
+/// This is equivalent to C's `in_addr`.
+#[repr(transparent)]
+pub struct Ipv4Addr(bindings::in_addr);
+
+impl Ipv4Addr {
+ /// A wildcard IPv4 address.
+ ///
+ /// Binding to this address means binding to all IPv4 addresses.
+ pub const ANY: Self = Self::new(0, 0, 0, 0);
+
+ /// The IPv4 loopback address.
+ pub const LOOPBACK: Self = Self::new(127, 0, 0, 1);
+
+ /// The IPv4 broadcast address.
+ pub const BROADCAST: Self = Self::new(255, 255, 255, 255);
+
+ /// Creates a new IPv4 address with the given components.
+ pub const fn new(a: u8, b: u8, c: u8, d: u8) -> Self {
+ Self(bindings::in_addr {
+ s_addr: u32::from_be_bytes([a, b, c, d]).to_be(),
+ })
+ }
+}
+
+/// An IPv6 address.
+///
+/// This is equivalent to C's `in6_addr`.
+#[repr(transparent)]
+pub struct Ipv6Addr(bindings::in6_addr);
+
+impl Ipv6Addr {
+ /// A wildcard IPv6 address.
+ ///
+ /// Binding to this address means binding to all IPv6 addresses.
+ pub const ANY: Self = Self::new(0, 0, 0, 0, 0, 0, 0, 0);
+
+ /// The IPv6 loopback address.
+ pub const LOOPBACK: Self = Self::new(0, 0, 0, 0, 0, 0, 0, 1);
+
+ /// Creates a new IPv6 address with the given components.
+ #[allow(clippy::too_many_arguments)]
+ pub const fn new(a: u16, b: u16, c: u16, d: u16, e: u16, f: u16, g: u16, h: u16) -> Self {
+ Self(bindings::in6_addr {
+ in6_u: bindings::in6_addr__bindgen_ty_1 {
+ u6_addr16: [
+ a.to_be(),
+ b.to_be(),
+ c.to_be(),
+ d.to_be(),
+ e.to_be(),
+ f.to_be(),
+ g.to_be(),
+ h.to_be(),
+ ],
+ },
+ })
+ }
+}
+
+/// A socket address.
+///
+/// It's an enum with either an IPv4 or IPv6 socket address.
+pub enum SocketAddr {
+ /// An IPv4 socket address.
+ V4(SocketAddrV4),
+
+ /// An IPv6 socket address.
+ V6(SocketAddrV6),
+}
+
+/// An IPv4 socket address.
+///
+/// This is equivalent to C's `sockaddr_in`.
+#[repr(transparent)]
+pub struct SocketAddrV4(bindings::sockaddr_in);
+
+impl SocketAddrV4 {
+ /// Creates a new IPv4 socket address.
+ pub const fn new(addr: Ipv4Addr, port: u16) -> Self {
+ Self(bindings::sockaddr_in {
+ sin_family: bindings::AF_INET as _,
+ sin_port: port.to_be(),
+ sin_addr: addr.0,
+ __pad: [0; 8],
+ })
+ }
+}
+
+/// An IPv6 socket address.
+///
+/// This is equivalent to C's `sockaddr_in6`.
+#[repr(transparent)]
+pub struct SocketAddrV6(bindings::sockaddr_in6);
+
+impl SocketAddrV6 {
+ /// Creates a new IPv6 socket address.
+ pub const fn new(addr: Ipv6Addr, port: u16, flowinfo: u32, scopeid: u32) -> Self {
+ Self(bindings::sockaddr_in6 {
+ sin6_family: bindings::AF_INET6 as _,
+ sin6_port: port.to_be(),
+ sin6_addr: addr.0,
+ sin6_flowinfo: flowinfo,
+ sin6_scope_id: scopeid,
+ })
+ }
+}
+
+/// A socket listening on a TCP port.
+///
+/// # Invariants
+///
+/// The socket pointer is always non-null and valid.
+pub struct TcpListener {
+ pub(crate) sock: *mut bindings::socket,
+}
+
+// SAFETY: `TcpListener` is just a wrapper for a kernel socket, which can be used from any thread.
+unsafe impl Send for TcpListener {}
+
+// SAFETY: `TcpListener` is just a wrapper for a kernel socket, which can be used from any thread.
+unsafe impl Sync for TcpListener {}
+
+impl TcpListener {
+ /// Creates a new TCP listener.
+ ///
+ /// It is configured to listen on the given socket address for the given namespace.
+ pub fn try_new(ns: &Namespace, addr: &SocketAddr) -> Result<Self> {
+ let mut socket = core::ptr::null_mut();
+ let (pf, addr, addrlen) = match addr {
+ SocketAddr::V4(addr) => (
+ bindings::PF_INET,
+ addr as *const _ as _,
+ core::mem::size_of::<bindings::sockaddr_in>(),
+ ),
+ SocketAddr::V6(addr) => (
+ bindings::PF_INET6,
+ addr as *const _ as _,
+ core::mem::size_of::<bindings::sockaddr_in6>(),
+ ),
+ };
+
+ // SAFETY: The namespace is valid and the output socket pointer is valid for write.
+ to_result(unsafe {
+ bindings::sock_create_kern(
+ ns.0.get(),
+ pf as _,
+ bindings::sock_type_SOCK_STREAM as _,
+ bindings::IPPROTO_TCP as _,
+ &mut socket,
+ )
+ })?;
+
+ // INVARIANT: The socket was just created, so it is valid.
+ let listener = Self { sock: socket };
+
+ // SAFETY: The type invariant guarantees that the socket is valid, and `addr` and `addrlen`
+ // were initialised based on valid values provided in the address enum.
+ to_result(unsafe { bindings::kernel_bind(socket, addr, addrlen as _) })?;
+
+ // SAFETY: The socket is valid per the type invariant.
+ to_result(unsafe { bindings::kernel_listen(socket, bindings::SOMAXCONN as _) })?;
+
+ Ok(listener)
+ }
+
+ /// Accepts a new connection.
+ ///
+ /// On success, returns the newly-accepted socket stream.
+ ///
+ /// If no connection is available to be accepted, one of two behaviours will occur:
+ /// - If `block` is `false`, returns [`crate::error::code::EAGAIN`];
+ /// - If `block` is `true`, blocks until an error occurs or some connection can be accepted.
+ pub fn accept(&self, block: bool) -> Result<TcpStream> {
+ let mut new = core::ptr::null_mut();
+ let flags = if block { 0 } else { bindings::O_NONBLOCK };
+ // SAFETY: The type invariant guarantees that the socket is valid, and the output argument
+ // is also valid for write.
+ to_result(unsafe { bindings::kernel_accept(self.sock, &mut new, flags as _) })?;
+ Ok(TcpStream { sock: new })
+ }
+}
+
+impl Drop for TcpListener {
+ fn drop(&mut self) {
+ // SAFETY: The type invariant guarantees that the socket is valid.
+ unsafe { bindings::sock_release(self.sock) };
+ }
+}
+
+/// A connected TCP socket.
+///
+/// # Invariants
+///
+/// The socket pointer is always non-null and valid.
+pub struct TcpStream {
+ pub(crate) sock: *mut bindings::socket,
+}
+
+// SAFETY: `TcpStream` is just a wrapper for a kernel socket, which can be used from any thread.
+unsafe impl Send for TcpStream {}
+
+// SAFETY: `TcpStream` is just a wrapper for a kernel socket, which can be used from any thread.
+unsafe impl Sync for TcpStream {}
+
+impl TcpStream {
+ /// Reads data from a connected socket.
+ ///
+ /// On success, returns the number of bytes read, which will be zero if the connection is
+ /// closed.
+ ///
+ /// If no data is immediately available for reading, one of two behaviours will occur:
+ /// - If `block` is `false`, returns [`crate::error::code::EAGAIN`];
+ /// - If `block` is `true`, blocks until an error occurs, the connection is closed, or some
+ /// becomes readable.
+ pub fn read(&self, buf: &mut [u8], block: bool) -> Result<usize> {
+ let mut msg = bindings::msghdr::default();
+ let mut vec = bindings::kvec {
+ iov_base: buf.as_mut_ptr().cast(),
+ iov_len: buf.len(),
+ };
+ // SAFETY: The type invariant guarantees that the socket is valid, and `vec` was
+ // initialised with the output buffer.
+ let r = unsafe {
+ bindings::kernel_recvmsg(
+ self.sock,
+ &mut msg,
+ &mut vec,
+ 1,
+ vec.iov_len,
+ if block { 0 } else { bindings::MSG_DONTWAIT } as _,
+ )
+ };
+ if r < 0 {
+ Err(Error::from_kernel_errno(r))
+ } else {
+ Ok(r as _)
+ }
+ }
+
+ /// Writes data to the connected socket.
+ ///
+ /// On success, returns the number of bytes written.
+ ///
+ /// If the send buffer of the socket is full, one of two behaviours will occur:
+ /// - If `block` is `false`, returns [`crate::error::code::EAGAIN`];
+ /// - If `block` is `true`, blocks until an error occurs or some data is written.
+ pub fn write(&self, buf: &[u8], block: bool) -> Result<usize> {
+ let mut msg = bindings::msghdr {
+ msg_flags: if block { 0 } else { bindings::MSG_DONTWAIT },
+ ..bindings::msghdr::default()
+ };
+ let mut vec = bindings::kvec {
+ iov_base: buf.as_ptr() as *mut u8 as _,
+ iov_len: buf.len(),
+ };
+ // SAFETY: The type invariant guarantees that the socket is valid, and `vec` was
+ // initialised with the input buffer.
+ let r = unsafe { bindings::kernel_sendmsg(self.sock, &mut msg, &mut vec, 1, vec.iov_len) };
+ if r < 0 {
+ Err(Error::from_kernel_errno(r))
+ } else {
+ Ok(r as _)
+ }
+ }
+}
+
+impl Drop for TcpStream {
+ fn drop(&mut self) {
+ // SAFETY: The type invariant guarantees that the socket is valid.
+ unsafe { bindings::sock_release(self.sock) };
+ }
+}
diff --git a/rust/kernel/net/filter.rs b/rust/kernel/net/filter.rs
new file mode 100644
index 000000000000..a50422d53848
--- /dev/null
+++ b/rust/kernel/net/filter.rs
@@ -0,0 +1,447 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Networking filters.
+//!
+//! C header: [`include/linux/netfilter.h`](../../../../../include/linux/netfilter.h)
+
+use crate::{
+ bindings,
+ error::{code::*, to_result},
+ net,
+ types::PointerWrapper,
+ ARef, AlwaysRefCounted, Result, ScopeGuard,
+};
+use alloc::boxed::Box;
+use core::{
+ marker::{PhantomData, PhantomPinned},
+ pin::Pin,
+};
+
+/// A network filter.
+pub trait Filter {
+ /// The type of the context data stored on registration and made available to the
+ /// [`Filter::filter`] function.
+ type Data: PointerWrapper + Sync = ();
+
+ /// Filters the packet stored in the given buffer.
+ ///
+ /// It dictates to the netfilter core what the fate of the packet should be.
+ fn filter(
+ _data: <Self::Data as PointerWrapper>::Borrowed<'_>,
+ _skb: &net::SkBuff,
+ ) -> Disposition;
+}
+
+/// Specifies the action to be taken by the netfilter core.
+pub enum Disposition {
+ /// Drop the packet.
+ Drop,
+
+ /// Accept the packet.
+ Accept,
+
+ /// The packet was stolen by the filter and must be treated as if it didn't exist.
+ Stolen,
+
+ /// Queue the packet to the given user-space queue.
+ Queue {
+ /// The identifier of the queue to which the packet should be added.
+ queue_id: u16,
+
+ /// Specifies the behaviour if a queue with the given identifier doesn't exist: if `true`,
+ /// the packet is accepted, otherwise it is rejected.
+ accept_if_queue_non_existent: bool,
+ },
+}
+
+/// The filter hook families.
+pub enum Family {
+ /// IPv4 and IPv6 packets.
+ INet(inet::Hook),
+
+ /// IPv4 packets.
+ Ipv4(ipv4::Hook, ipv4::PriorityBase),
+
+ /// All packets through a device.
+ ///
+ /// When this family is used, a device _must_ be specified.
+ NetDev(netdev::Hook),
+
+ /// IPv6 packets.
+ Ipv6(ipv6::Hook, ipv6::PriorityBase),
+
+ /// Address resolution protocol (ARP) packets.
+ Arp(arp::Hook),
+}
+
+/// A registration of a networking filter.
+///
+/// # Examples
+///
+/// The following is an example of a function that attaches an inbound filter (that always accepts
+/// all packets after printing their lengths) on the specified device (in the `init` ns).
+///
+/// ```
+/// use kernel::net::{self, filter as netfilter};
+///
+/// struct MyFilter;
+/// impl netfilter::Filter for MyFilter {
+/// fn filter(_data: (), skb: &net::SkBuff) -> netfilter::Disposition {
+/// pr_info!("Packet of length {}\n", skb.len());
+/// netfilter::Disposition::Accept
+/// }
+/// }
+///
+/// fn register(name: &CStr) -> Result<Pin<Box<netfilter::Registration<MyFilter>>>> {
+/// let ns = net::init_ns();
+/// let dev = ns.dev_get_by_name(name).ok_or(ENOENT)?;
+/// netfilter::Registration::new_pinned(
+/// netfilter::Family::NetDev(netfilter::netdev::Hook::Ingress),
+/// 0,
+/// ns.into(),
+/// Some(dev),
+/// (),
+/// )
+/// }
+/// ```
+#[derive(Default)]
+pub struct Registration<T: Filter> {
+ hook: bindings::nf_hook_ops,
+ // When `ns` is `Some(_)`, the hook is registered.
+ ns: Option<ARef<net::Namespace>>,
+ dev: Option<ARef<net::Device>>,
+ _p: PhantomData<T>,
+ _pinned: PhantomPinned,
+}
+
+// SAFETY: `Registration` does not expose any of its state across threads.
+unsafe impl<T: Filter> Sync for Registration<T> {}
+
+impl<T: Filter> Registration<T> {
+ /// Creates a new [`Registration`] but does not register it yet.
+ ///
+ /// It is allowed to move.
+ pub fn new() -> Self {
+ Self {
+ hook: bindings::nf_hook_ops::default(),
+ dev: None,
+ ns: None,
+ _p: PhantomData,
+ _pinned: PhantomPinned,
+ }
+ }
+
+ /// Creates a new filter registration and registers it.
+ ///
+ /// Returns a pinned heap-allocated representation of the registration.
+ pub fn new_pinned(
+ family: Family,
+ priority: i32,
+ ns: ARef<net::Namespace>,
+ dev: Option<ARef<net::Device>>,
+ data: T::Data,
+ ) -> Result<Pin<Box<Self>>> {
+ let mut filter = Pin::from(Box::try_new(Self::new())?);
+ filter.as_mut().register(family, priority, ns, dev, data)?;
+ Ok(filter)
+ }
+
+ /// Registers a network filter.
+ ///
+ /// It must be pinned because the C portion of the kernel stores a pointer to it while it is
+ /// registered.
+ ///
+ /// The priority is relative to the family's base priority. For example, if the base priority
+ /// is `100` and `priority` is `-1`, the actual priority will be `99`. If a family doesn't
+ /// explicitly allow a base to be specified, `0` is assumed.
+ pub fn register(
+ self: Pin<&mut Self>,
+ family: Family,
+ priority: i32,
+ ns: ARef<net::Namespace>,
+ dev: Option<ARef<net::Device>>,
+ data: T::Data,
+ ) -> Result {
+ // SAFETY: We must ensure that we never move out of `this`.
+ let this = unsafe { self.get_unchecked_mut() };
+ if this.ns.is_some() {
+ // Already registered.
+ return Err(EINVAL);
+ }
+
+ let data_pointer = data.into_pointer();
+
+ // SAFETY: `data_pointer` comes from the call to `data.into_pointer()` above.
+ let guard = ScopeGuard::new(|| unsafe {
+ T::Data::from_pointer(data_pointer);
+ });
+
+ let mut pri_base = 0i32;
+ match family {
+ Family::INet(hook) => {
+ this.hook.pf = bindings::NFPROTO_INET as _;
+ this.hook.hooknum = hook as _;
+ }
+ Family::Ipv4(hook, pbase) => {
+ this.hook.pf = bindings::NFPROTO_IPV4 as _;
+ this.hook.hooknum = hook as _;
+ pri_base = pbase as _;
+ }
+ Family::Ipv6(hook, pbase) => {
+ this.hook.pf = bindings::NFPROTO_IPV6 as _;
+ this.hook.hooknum = hook as _;
+ pri_base = pbase as _;
+ }
+ Family::NetDev(hook) => {
+ this.hook.pf = bindings::NFPROTO_NETDEV as _;
+ this.hook.hooknum = hook as _;
+ }
+ Family::Arp(hook) => {
+ this.hook.pf = bindings::NFPROTO_ARP as _;
+ this.hook.hooknum = hook as _;
+ }
+ }
+
+ this.hook.priority = pri_base.saturating_add(priority);
+ this.hook.priv_ = data_pointer as _;
+ this.hook.hook = Some(Self::hook_callback);
+ crate::static_assert!(bindings::nf_hook_ops_type_NF_HOOK_OP_UNDEFINED == 0);
+
+ if let Some(ref device) = dev {
+ this.hook.dev = device.0.get();
+ }
+
+ // SAFETY: `ns` has a valid reference to the namespace, and `this.hook` was just
+ // initialised above, so they're both valid.
+ to_result(unsafe { bindings::nf_register_net_hook(ns.0.get(), &this.hook) })?;
+
+ this.dev = dev;
+ this.ns = Some(ns);
+ guard.dismiss();
+ Ok(())
+ }
+
+ unsafe extern "C" fn hook_callback(
+ priv_: *mut core::ffi::c_void,
+ skb: *mut bindings::sk_buff,
+ _state: *const bindings::nf_hook_state,
+ ) -> core::ffi::c_uint {
+ // SAFETY: `priv_` was initialised on registration by a value returned from
+ // `T::Data::into_pointer`, and it remains valid until the hook is unregistered.
+ let data = unsafe { T::Data::borrow(priv_) };
+
+ // SAFETY: The C contract guarantees that `skb` remains valid for the duration of this
+ // function call.
+ match T::filter(data, unsafe { net::SkBuff::from_ptr(skb) }) {
+ Disposition::Drop => bindings::NF_DROP,
+ Disposition::Accept => bindings::NF_ACCEPT,
+ Disposition::Stolen => {
+ // SAFETY: This function takes over ownership of `skb` when it returns `NF_STOLEN`,
+ // so we decrement the refcount here to avoid a leak.
+ unsafe { net::SkBuff::dec_ref(core::ptr::NonNull::new(skb).unwrap().cast()) };
+ bindings::NF_STOLEN
+ }
+ Disposition::Queue {
+ queue_id,
+ accept_if_queue_non_existent,
+ } => {
+ // SAFETY: Just an FFI call, no additional safety requirements.
+ let verdict = unsafe { bindings::NF_QUEUE_NR(queue_id as _) };
+ if accept_if_queue_non_existent {
+ verdict | bindings::NF_VERDICT_FLAG_QUEUE_BYPASS
+ } else {
+ verdict
+ }
+ }
+ }
+ }
+}
+
+impl<T: Filter> Drop for Registration<T> {
+ fn drop(&mut self) {
+ if let Some(ref ns) = self.ns {
+ // SAFETY: `self.ns` is `Some(_)` only when a previous call to `nf_register_net_hook`
+ // succeeded. And the arguments are the same.
+ unsafe { bindings::nf_unregister_net_hook(ns.0.get(), &self.hook) };
+
+ // `self.hook.priv_` was initialised during registration to a value returned from
+ // `T::Data::into_pointer`, so it is ok to convert back here.
+ unsafe { T::Data::from_pointer(self.hook.priv_) };
+ }
+ }
+}
+
+/// Definitions used when defining hooks for the [`Family::NetDev`] family.
+pub mod netdev {
+ use crate::bindings;
+
+ /// Hooks allowed in the [`super::Family::NetDev`] family.
+ #[repr(u32)]
+ pub enum Hook {
+ /// All inbound packets through the given device.
+ Ingress = bindings::nf_dev_hooks_NF_NETDEV_INGRESS,
+
+ /// All outbound packets through the given device.
+ Egress = bindings::nf_dev_hooks_NF_NETDEV_EGRESS,
+ }
+}
+
+/// Definitions used when defining hooks for the [`Family::Ipv4`] family.
+pub mod ipv4 {
+ use crate::bindings;
+
+ /// Hooks allowed in [`super::Family::Ipv4`] family.
+ pub type Hook = super::inet::Hook;
+
+ /// The base priority for [`super::Family::Ipv4`] hooks.
+ ///
+ /// The actual priority is the base priority plus the priority specified when registering.
+ #[repr(i32)]
+ pub enum PriorityBase {
+ /// Same as the `NF_IP_PRI_FIRST` C constant.
+ First = bindings::nf_ip_hook_priorities_NF_IP_PRI_FIRST,
+
+ /// Same as the `NF_IP_PRI_RAW_BEFORE_DEFRAG` C constant.
+ RawBeforeDefrag = bindings::nf_ip_hook_priorities_NF_IP_PRI_RAW_BEFORE_DEFRAG,
+
+ /// Same as the `NF_IP_PRI_CONNTRACK_DEFRAG` C constant.
+ ConnTrackDefrag = bindings::nf_ip_hook_priorities_NF_IP_PRI_CONNTRACK_DEFRAG,
+
+ /// Same as the `NF_IP_PRI_RAW` C constant.
+ Raw = bindings::nf_ip_hook_priorities_NF_IP_PRI_RAW,
+
+ /// Same as the `NF_IP_PRI_SELINUX_FIRST` C constant.
+ SeLinuxFirst = bindings::nf_ip_hook_priorities_NF_IP_PRI_SELINUX_FIRST,
+
+ /// Same as the `NF_IP_PRI_CONNTRACK` C constant.
+ ConnTrack = bindings::nf_ip_hook_priorities_NF_IP_PRI_CONNTRACK,
+
+ /// Same as the `NF_IP_PRI_MANGLE` C constant.
+ Mangle = bindings::nf_ip_hook_priorities_NF_IP_PRI_MANGLE,
+
+ /// Same as the `NF_IP_PRI_NAT_DST` C constant.
+ NatDst = bindings::nf_ip_hook_priorities_NF_IP_PRI_NAT_DST,
+
+ /// Same as the `NF_IP_PRI_FILTER` C constant.
+ Filter = bindings::nf_ip_hook_priorities_NF_IP_PRI_FILTER,
+
+ /// Same as the `NF_IP_PRI_SECURITY` C constant.
+ Security = bindings::nf_ip_hook_priorities_NF_IP_PRI_SECURITY,
+
+ /// Same as the `NF_IP_PRI_NAT_SRC` C constant.
+ NatSrc = bindings::nf_ip_hook_priorities_NF_IP_PRI_NAT_SRC,
+
+ /// Same as the `NF_IP_PRI_SELINUX_LAST` C constant.
+ SeLinuxLast = bindings::nf_ip_hook_priorities_NF_IP_PRI_SELINUX_LAST,
+
+ /// Same as the `NF_IP_PRI_CONNTRACK_HELPER` C constant.
+ ConnTrackHelper = bindings::nf_ip_hook_priorities_NF_IP_PRI_CONNTRACK_HELPER,
+
+ /// Same as the `NF_IP_PRI_LAST` and `NF_IP_PRI_CONNTRACK_CONFIRM` C constants.
+ Last = bindings::nf_ip_hook_priorities_NF_IP_PRI_LAST,
+ }
+}
+
+/// Definitions used when defining hooks for the [`Family::Ipv6`] family.
+pub mod ipv6 {
+ use crate::bindings;
+
+ /// Hooks allowed in [`super::Family::Ipv6`] family.
+ pub type Hook = super::inet::Hook;
+
+ /// The base priority for [`super::Family::Ipv6`] hooks.
+ ///
+ /// The actual priority is the base priority plus the priority specified when registering.
+ #[repr(i32)]
+ pub enum PriorityBase {
+ /// Same as the `NF_IP6_PRI_FIRST` C constant.
+ First = bindings::nf_ip6_hook_priorities_NF_IP6_PRI_FIRST,
+
+ /// Same as the `NF_IP6_PRI_RAW_BEFORE_DEFRAG` C constant.
+ RawBeforeDefrag = bindings::nf_ip6_hook_priorities_NF_IP6_PRI_RAW_BEFORE_DEFRAG,
+
+ /// Same as the `NF_IP6_PRI_CONNTRACK_DEFRAG` C constant.
+ ConnTrackDefrag = bindings::nf_ip6_hook_priorities_NF_IP6_PRI_CONNTRACK_DEFRAG,
+
+ /// Same as the `NF_IP6_PRI_RAW` C constant.
+ Raw = bindings::nf_ip6_hook_priorities_NF_IP6_PRI_RAW,
+
+ /// Same as the `NF_IP6_PRI_SELINUX_FIRST` C constant.
+ SeLinuxFirst = bindings::nf_ip6_hook_priorities_NF_IP6_PRI_SELINUX_FIRST,
+
+ /// Same as the `NF_IP6_PRI_CONNTRACK` C constant.
+ ConnTrack = bindings::nf_ip6_hook_priorities_NF_IP6_PRI_CONNTRACK,
+
+ /// Same as the `NF_IP6_PRI_MANGLE` C constant.
+ Mangle = bindings::nf_ip6_hook_priorities_NF_IP6_PRI_MANGLE,
+
+ /// Same as the `NF_IP6_PRI_NAT_DST` C constant.
+ NatDst = bindings::nf_ip6_hook_priorities_NF_IP6_PRI_NAT_DST,
+
+ /// Same as the `NF_IP6_PRI_FILTER` C constant.
+ Filter = bindings::nf_ip6_hook_priorities_NF_IP6_PRI_FILTER,
+
+ /// Same as the `NF_IP6_PRI_SECURITY` C constant.
+ Security = bindings::nf_ip6_hook_priorities_NF_IP6_PRI_SECURITY,
+
+ /// Same as the `NF_IP6_PRI_NAT_SRC` C constant.
+ NatSrc = bindings::nf_ip6_hook_priorities_NF_IP6_PRI_NAT_SRC,
+
+ /// Same as the `NF_IP6_PRI_SELINUX_LAST` C constant.
+ SeLinuxLast = bindings::nf_ip6_hook_priorities_NF_IP6_PRI_SELINUX_LAST,
+
+ /// Same as the `NF_IP6_PRI_CONNTRACK_HELPER` C constant.
+ ConnTrackHelper = bindings::nf_ip6_hook_priorities_NF_IP6_PRI_CONNTRACK_HELPER,
+
+ /// Same as the `NF_IP6_PRI_LAST` C constant.
+ Last = bindings::nf_ip6_hook_priorities_NF_IP6_PRI_LAST,
+ }
+}
+
+/// Definitions used when defining hooks for the [`Family::Arp`] family.
+pub mod arp {
+ use crate::bindings;
+
+ /// Hooks allowed in the [`super::Family::Arp`] family.
+ #[repr(u32)]
+ pub enum Hook {
+ /// Inbound ARP packets.
+ In = bindings::NF_ARP_IN,
+
+ /// Outbound ARP packets.
+ Out = bindings::NF_ARP_OUT,
+
+ /// Forwarded ARP packets.
+ Forward = bindings::NF_ARP_FORWARD,
+ }
+}
+
+/// Definitions used when defining hooks for the [`Family::INet`] family.
+pub mod inet {
+ use crate::bindings;
+
+ /// Hooks allowed in the [`super::Family::INet`], [`super::Family::Ipv4`], and
+ /// [`super::Family::Ipv6`] families.
+ #[repr(u32)]
+ pub enum Hook {
+ /// Inbound packets before routing decisions are made (i.e., before it's determined if the
+ /// packet is to be delivered locally or forwarded to another host).
+ PreRouting = bindings::nf_inet_hooks_NF_INET_PRE_ROUTING as _,
+
+ /// Inbound packets that are meant to be delivered locally.
+ LocalIn = bindings::nf_inet_hooks_NF_INET_LOCAL_IN as _,
+
+ /// Inbound packets that are meant to be forwarded to another host.
+ Forward = bindings::nf_inet_hooks_NF_INET_FORWARD as _,
+
+ /// Outbound packet created by the local networking stack.
+ LocalOut = bindings::nf_inet_hooks_NF_INET_LOCAL_OUT as _,
+
+ /// All outbound packets (i.e., generated locally or being forwarded to another host).
+ PostRouting = bindings::nf_inet_hooks_NF_INET_POST_ROUTING as _,
+
+ /// Equivalent to [`super::netdev::Hook::Ingress`], so a device must be specified. Packets
+ /// of all types (not just ipv4/ipv6) will be delivered to the filter.
+ Ingress = bindings::nf_inet_hooks_NF_INET_INGRESS as _,
+ }
+}
diff --git a/rust/kernel/of.rs b/rust/kernel/of.rs
new file mode 100644
index 000000000000..cdcd83244337
--- /dev/null
+++ b/rust/kernel/of.rs
@@ -0,0 +1,63 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Devicetree and Open Firmware abstractions.
+//!
+//! C header: [`include/linux/of_*.h`](../../../../include/linux/of_*.h)
+
+use crate::{bindings, driver, str::BStr};
+
+/// An open firmware device id.
+#[derive(Clone, Copy)]
+pub enum DeviceId {
+ /// An open firmware device id where only a compatible string is specified.
+ Compatible(&'static BStr),
+}
+
+/// Defines a const open firmware device id table that also carries per-entry data/context/info.
+///
+/// The name of the const is `OF_DEVICE_ID_TABLE`, which is what buses are expected to name their
+/// open firmware tables.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::define_of_id_table;
+/// use kernel::of;
+///
+/// define_of_id_table! {u32, [
+/// (of::DeviceId::Compatible(b"test-device1,test-device2"), Some(0xff)),
+/// (of::DeviceId::Compatible(b"test-device3"), None),
+/// ]};
+/// ```
+#[macro_export]
+macro_rules! define_of_id_table {
+ ($data_type:ty, $($t:tt)*) => {
+ $crate::define_id_table!(OF_DEVICE_ID_TABLE, $crate::of::DeviceId, $data_type, $($t)*);
+ };
+}
+
+// SAFETY: `ZERO` is all zeroed-out and `to_rawid` stores `offset` in `of_device_id::data`.
+unsafe impl const driver::RawDeviceId for DeviceId {
+ type RawType = bindings::of_device_id;
+ const ZERO: Self::RawType = bindings::of_device_id {
+ name: [0; 32],
+ type_: [0; 32],
+ compatible: [0; 128],
+ data: core::ptr::null(),
+ };
+
+ fn to_rawid(&self, offset: isize) -> Self::RawType {
+ let DeviceId::Compatible(compatible) = self;
+ let mut id = Self::ZERO;
+ let mut i = 0;
+ while i < compatible.len() {
+ // If `compatible` does not fit in `id.compatible`, an "index out of bounds" build time
+ // error will be triggered.
+ id.compatible[i] = compatible[i] as _;
+ i += 1;
+ }
+ id.compatible[i] = b'\0' as _;
+ id.data = offset as _;
+ id
+ }
+}
diff --git a/rust/kernel/pages.rs b/rust/kernel/pages.rs
new file mode 100644
index 000000000000..f2bb26810cd7
--- /dev/null
+++ b/rust/kernel/pages.rs
@@ -0,0 +1,144 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Kernel page allocation and management.
+//!
+//! TODO: This module is a work in progress.
+
+use crate::{
+ bindings, error::code::*, io_buffer::IoBufferReader, user_ptr::UserSlicePtrReader, Result,
+ PAGE_SIZE,
+};
+use core::{marker::PhantomData, ptr};
+
+/// A set of physical pages.
+///
+/// `Pages` holds a reference to a set of pages of order `ORDER`. Having the order as a generic
+/// const allows the struct to have the same size as a pointer.
+///
+/// # Invariants
+///
+/// The pointer `Pages::pages` is valid and points to 2^ORDER pages.
+pub struct Pages<const ORDER: u32> {
+ pub(crate) pages: *mut bindings::page,
+}
+
+impl<const ORDER: u32> Pages<ORDER> {
+ /// Allocates a new set of contiguous pages.
+ pub fn new() -> Result<Self> {
+ // TODO: Consider whether we want to allow callers to specify flags.
+ // SAFETY: This only allocates pages. We check that it succeeds in the next statement.
+ let pages = unsafe {
+ bindings::alloc_pages(
+ bindings::GFP_KERNEL | bindings::__GFP_ZERO | bindings::__GFP_HIGHMEM,
+ ORDER,
+ )
+ };
+ if pages.is_null() {
+ return Err(ENOMEM);
+ }
+ // INVARIANTS: We checked that the allocation above succeeded.
+ Ok(Self { pages })
+ }
+
+ /// Copies data from the given [`UserSlicePtrReader`] into the pages.
+ pub fn copy_into_page(
+ &self,
+ reader: &mut UserSlicePtrReader,
+ offset: usize,
+ len: usize,
+ ) -> Result {
+ // TODO: For now this only works on the first page.
+ let end = offset.checked_add(len).ok_or(EINVAL)?;
+ if end > PAGE_SIZE {
+ return Err(EINVAL);
+ }
+
+ let mapping = self.kmap(0).ok_or(EINVAL)?;
+
+ // SAFETY: We ensured that the buffer was valid with the check above.
+ unsafe { reader.read_raw((mapping.ptr as usize + offset) as _, len) }?;
+ Ok(())
+ }
+
+ /// Maps the pages and reads from them into the given buffer.
+ ///
+ /// # Safety
+ ///
+ /// Callers must ensure that the destination buffer is valid for the given length.
+ /// Additionally, if the raw buffer is intended to be recast, they must ensure that the data
+ /// can be safely cast; [`crate::io_buffer::ReadableFromBytes`] has more details about it.
+ pub unsafe fn read(&self, dest: *mut u8, offset: usize, len: usize) -> Result {
+ // TODO: For now this only works on the first page.
+ let end = offset.checked_add(len).ok_or(EINVAL)?;
+ if end > PAGE_SIZE {
+ return Err(EINVAL);
+ }
+
+ let mapping = self.kmap(0).ok_or(EINVAL)?;
+ unsafe { ptr::copy((mapping.ptr as *mut u8).add(offset), dest, len) };
+ Ok(())
+ }
+
+ /// Maps the pages and writes into them from the given buffer.
+ ///
+ /// # Safety
+ ///
+ /// Callers must ensure that the buffer is valid for the given length. Additionally, if the
+ /// page is (or will be) mapped by userspace, they must ensure that no kernel data is leaked
+ /// through padding if it was cast from another type; [`crate::io_buffer::WritableToBytes`] has
+ /// more details about it.
+ pub unsafe fn write(&self, src: *const u8, offset: usize, len: usize) -> Result {
+ // TODO: For now this only works on the first page.
+ let end = offset.checked_add(len).ok_or(EINVAL)?;
+ if end > PAGE_SIZE {
+ return Err(EINVAL);
+ }
+
+ let mapping = self.kmap(0).ok_or(EINVAL)?;
+ unsafe { ptr::copy(src, (mapping.ptr as *mut u8).add(offset), len) };
+ Ok(())
+ }
+
+ /// Maps the page at index `index`.
+ fn kmap(&self, index: usize) -> Option<PageMapping<'_>> {
+ if index >= 1usize << ORDER {
+ return None;
+ }
+
+ // SAFETY: We checked above that `index` is within range.
+ let page = unsafe { self.pages.add(index) };
+
+ // SAFETY: `page` is valid based on the checks above.
+ let ptr = unsafe { bindings::kmap(page) };
+ if ptr.is_null() {
+ return None;
+ }
+
+ Some(PageMapping {
+ page,
+ ptr,
+ _phantom: PhantomData,
+ })
+ }
+}
+
+impl<const ORDER: u32> Drop for Pages<ORDER> {
+ fn drop(&mut self) {
+ // SAFETY: By the type invariants, we know the pages are allocated with the given order.
+ unsafe { bindings::__free_pages(self.pages, ORDER) };
+ }
+}
+
+struct PageMapping<'a> {
+ page: *mut bindings::page,
+ ptr: *mut core::ffi::c_void,
+ _phantom: PhantomData<&'a i32>,
+}
+
+impl Drop for PageMapping<'_> {
+ fn drop(&mut self) {
+ // SAFETY: An instance of `PageMapping` is created only when `kmap` succeeded for the given
+ // page, so it is safe to unmap it here.
+ unsafe { bindings::kunmap(self.page) };
+ }
+}
diff --git a/rust/kernel/platform.rs b/rust/kernel/platform.rs
new file mode 100644
index 000000000000..d8cc0e0120aa
--- /dev/null
+++ b/rust/kernel/platform.rs
@@ -0,0 +1,223 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Platform devices and drivers.
+//!
+//! Also called `platdev`, `pdev`.
+//!
+//! C header: [`include/linux/platform_device.h`](../../../../include/linux/platform_device.h)
+
+use crate::{
+ bindings,
+ device::{self, RawDevice},
+ driver,
+ error::{from_kernel_result, Result},
+ of,
+ str::CStr,
+ to_result,
+ types::PointerWrapper,
+ ThisModule,
+};
+
+/// A registration of a platform driver.
+pub type Registration<T> = driver::Registration<Adapter<T>>;
+
+/// An adapter for the registration of platform drivers.
+pub struct Adapter<T: Driver>(T);
+
+impl<T: Driver> driver::DriverOps for Adapter<T> {
+ type RegType = bindings::platform_driver;
+
+ unsafe fn register(
+ reg: *mut bindings::platform_driver,
+ name: &'static CStr,
+ module: &'static ThisModule,
+ ) -> Result {
+ // SAFETY: By the safety requirements of this function (defined in the trait definition),
+ // `reg` is non-null and valid.
+ let pdrv = unsafe { &mut *reg };
+
+ pdrv.driver.name = name.as_char_ptr();
+ pdrv.probe = Some(Self::probe_callback);
+ pdrv.remove = Some(Self::remove_callback);
+ if let Some(t) = T::OF_DEVICE_ID_TABLE {
+ pdrv.driver.of_match_table = t.as_ref();
+ }
+ // SAFETY:
+ // - `pdrv` lives at least until the call to `platform_driver_unregister()` returns.
+ // - `name` pointer has static lifetime.
+ // - `module.0` lives at least as long as the module.
+ // - `probe()` and `remove()` are static functions.
+ // - `of_match_table` is either a raw pointer with static lifetime,
+ // as guaranteed by the [`driver::IdTable`] type, or null.
+ to_result(unsafe { bindings::__platform_driver_register(reg, module.0) })
+ }
+
+ unsafe fn unregister(reg: *mut bindings::platform_driver) {
+ // SAFETY: By the safety requirements of this function (defined in the trait definition),
+ // `reg` was passed (and updated) by a previous successful call to
+ // `platform_driver_register`.
+ unsafe { bindings::platform_driver_unregister(reg) };
+ }
+}
+
+impl<T: Driver> Adapter<T> {
+ fn get_id_info(dev: &Device) -> Option<&'static T::IdInfo> {
+ let table = T::OF_DEVICE_ID_TABLE?;
+
+ // SAFETY: `table` has static lifetime, so it is valid for read. `dev` is guaranteed to be
+ // valid while it's alive, so is the raw device returned by it.
+ let id = unsafe { bindings::of_match_device(table.as_ref(), dev.raw_device()) };
+ if id.is_null() {
+ return None;
+ }
+
+ // SAFETY: `id` is a pointer within the static table, so it's always valid.
+ let offset = unsafe { (*id).data };
+ if offset.is_null() {
+ return None;
+ }
+
+ // SAFETY: The offset comes from a previous call to `offset_from` in `IdArray::new`, which
+ // guarantees that the resulting pointer is within the table.
+ let ptr = unsafe {
+ id.cast::<u8>()
+ .offset(offset as _)
+ .cast::<Option<T::IdInfo>>()
+ };
+
+ // SAFETY: The id table has a static lifetime, so `ptr` is guaranteed to be valid for read.
+ unsafe { (&*ptr).as_ref() }
+ }
+
+ extern "C" fn probe_callback(pdev: *mut bindings::platform_device) -> core::ffi::c_int {
+ from_kernel_result! {
+ // SAFETY: `pdev` is valid by the contract with the C code. `dev` is alive only for the
+ // duration of this call, so it is guaranteed to remain alive for the lifetime of
+ // `pdev`.
+ let mut dev = unsafe { Device::from_ptr(pdev) };
+ let info = Self::get_id_info(&dev);
+ let data = T::probe(&mut dev, info)?;
+ // SAFETY: `pdev` is guaranteed to be a valid, non-null pointer.
+ unsafe { bindings::platform_set_drvdata(pdev, data.into_pointer() as _) };
+ Ok(0)
+ }
+ }
+
+ extern "C" fn remove_callback(pdev: *mut bindings::platform_device) -> core::ffi::c_int {
+ from_kernel_result! {
+ // SAFETY: `pdev` is guaranteed to be a valid, non-null pointer.
+ let ptr = unsafe { bindings::platform_get_drvdata(pdev) };
+ // SAFETY:
+ // - we allocated this pointer using `T::Data::into_pointer`,
+ // so it is safe to turn back into a `T::Data`.
+ // - the allocation happened in `probe`, no-one freed the memory,
+ // `remove` is the canonical kernel location to free driver data. so OK
+ // to convert the pointer back to a Rust structure here.
+ let data = unsafe { T::Data::from_pointer(ptr) };
+ let ret = T::remove(&data);
+ <T::Data as driver::DeviceRemoval>::device_remove(&data);
+ ret?;
+ Ok(0)
+ }
+ }
+}
+
+/// A platform driver.
+pub trait Driver {
+ /// Data stored on device by driver.
+ ///
+ /// Corresponds to the data set or retrieved via the kernel's
+ /// `platform_{set,get}_drvdata()` functions.
+ ///
+ /// Require that `Data` implements `PointerWrapper`. We guarantee to
+ /// never move the underlying wrapped data structure. This allows
+ type Data: PointerWrapper + Send + Sync + driver::DeviceRemoval = ();
+
+ /// The type holding information about each device id supported by the driver.
+ type IdInfo: 'static = ();
+
+ /// The table of device ids supported by the driver.
+ const OF_DEVICE_ID_TABLE: Option<driver::IdTable<'static, of::DeviceId, Self::IdInfo>> = None;
+
+ /// Platform driver probe.
+ ///
+ /// Called when a new platform device is added or discovered.
+ /// Implementers should attempt to initialize the device here.
+ fn probe(dev: &mut Device, id_info: Option<&Self::IdInfo>) -> Result<Self::Data>;
+
+ /// Platform driver remove.
+ ///
+ /// Called when a platform device is removed.
+ /// Implementers should prepare the device for complete removal here.
+ fn remove(_data: &Self::Data) -> Result {
+ Ok(())
+ }
+}
+
+/// A platform device.
+///
+/// # Invariants
+///
+/// The field `ptr` is non-null and valid for the lifetime of the object.
+pub struct Device {
+ ptr: *mut bindings::platform_device,
+}
+
+impl Device {
+ /// Creates a new device from the given pointer.
+ ///
+ /// # Safety
+ ///
+ /// `ptr` must be non-null and valid. It must remain valid for the lifetime of the returned
+ /// instance.
+ unsafe fn from_ptr(ptr: *mut bindings::platform_device) -> Self {
+ // INVARIANT: The safety requirements of the function ensure the lifetime invariant.
+ Self { ptr }
+ }
+
+ /// Returns id of the platform device.
+ pub fn id(&self) -> i32 {
+ // SAFETY: By the type invariants, we know that `self.ptr` is non-null and valid.
+ unsafe { (*self.ptr).id }
+ }
+}
+
+// SAFETY: The device returned by `raw_device` is the raw platform device.
+unsafe impl device::RawDevice for Device {
+ fn raw_device(&self) -> *mut bindings::device {
+ // SAFETY: By the type invariants, we know that `self.ptr` is non-null and valid.
+ unsafe { &mut (*self.ptr).dev }
+ }
+}
+
+/// Declares a kernel module that exposes a single platform driver.
+///
+/// # Examples
+///
+/// ```ignore
+/// # use kernel::{platform, define_of_id_table, module_platform_driver};
+/// #
+/// struct MyDriver;
+/// impl platform::Driver for MyDriver {
+/// // [...]
+/// # fn probe(_dev: &mut platform::Device, _id_info: Option<&Self::IdInfo>) -> Result {
+/// # Ok(())
+/// # }
+/// # define_of_id_table! {(), [
+/// # (of::DeviceId::Compatible(b"brcm,bcm2835-rng"), None),
+/// # ]}
+/// }
+///
+/// module_platform_driver! {
+/// type: MyDriver,
+/// name: b"module_name",
+/// author: b"Author name",
+/// license: b"GPL",
+/// }
+/// ```
+#[macro_export]
+macro_rules! module_platform_driver {
+ ($($f:tt)*) => {
+ $crate::module_driver!(<T>, $crate::platform::Adapter<T>, { $($f)* });
+ };
+}
diff --git a/rust/kernel/power.rs b/rust/kernel/power.rs
new file mode 100644
index 000000000000..ef788557b269
--- /dev/null
+++ b/rust/kernel/power.rs
@@ -0,0 +1,118 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Power management interfaces.
+//!
+//! C header: [`include/linux/pm.h`](../../../../include/linux/pm.h)
+
+#![allow(dead_code)]
+
+use crate::{bindings, error::from_kernel_result, types::PointerWrapper, Result};
+use core::marker::PhantomData;
+
+/// Corresponds to the kernel's `struct dev_pm_ops`.
+///
+/// It is meant to be implemented by drivers that support power-management operations.
+pub trait Operations {
+ /// The type of the context data stored by the driver on each device.
+ type Data: PointerWrapper + Sync + Send;
+
+ /// Called before the system goes into a sleep state.
+ fn suspend(_data: <Self::Data as PointerWrapper>::Borrowed<'_>) -> Result {
+ Ok(())
+ }
+
+ /// Called after the system comes back from a sleep state.
+ fn resume(_data: <Self::Data as PointerWrapper>::Borrowed<'_>) -> Result {
+ Ok(())
+ }
+
+ /// Called before creating a hibernation image.
+ fn freeze(_data: <Self::Data as PointerWrapper>::Borrowed<'_>) -> Result {
+ Ok(())
+ }
+
+ /// Called after the system is restored from a hibernation image.
+ fn restore(_data: <Self::Data as PointerWrapper>::Borrowed<'_>) -> Result {
+ Ok(())
+ }
+}
+
+macro_rules! pm_callback {
+ ($callback:ident, $method:ident) => {
+ unsafe extern "C" fn $callback<T: Operations>(
+ dev: *mut bindings::device,
+ ) -> core::ffi::c_int {
+ from_kernel_result! {
+ // SAFETY: `dev` is valid as it was passed in by the C portion.
+ let ptr = unsafe { bindings::dev_get_drvdata(dev) };
+ // SAFETY: By the safety requirements of `OpsTable::build`, we know that `ptr` came
+ // from a previous call to `T::Data::into_pointer`.
+ let data = unsafe { T::Data::borrow(ptr) };
+ T::$method(data)?;
+ Ok(0)
+ }
+ }
+ };
+}
+
+pm_callback!(suspend_callback, suspend);
+pm_callback!(resume_callback, resume);
+pm_callback!(freeze_callback, freeze);
+pm_callback!(restore_callback, restore);
+
+pub(crate) struct OpsTable<T: Operations>(PhantomData<*const T>);
+
+impl<T: Operations> OpsTable<T> {
+ const VTABLE: bindings::dev_pm_ops = bindings::dev_pm_ops {
+ prepare: None,
+ complete: None,
+ suspend: Some(suspend_callback::<T>),
+ resume: Some(resume_callback::<T>),
+ freeze: Some(freeze_callback::<T>),
+ thaw: None,
+ poweroff: None,
+ restore: Some(restore_callback::<T>),
+ suspend_late: None,
+ resume_early: None,
+ freeze_late: None,
+ thaw_early: None,
+ poweroff_late: None,
+ restore_early: None,
+ suspend_noirq: None,
+ resume_noirq: None,
+ freeze_noirq: None,
+ thaw_noirq: None,
+ poweroff_noirq: None,
+ restore_noirq: None,
+ runtime_suspend: None,
+ runtime_resume: None,
+ runtime_idle: None,
+ };
+
+ /// Builds an instance of `struct dev_pm_ops`.
+ ///
+ /// # Safety
+ ///
+ /// The caller must ensure that `dev_get_drvdata` will result in a value returned by
+ /// [`T::Data::into_pointer`].
+ pub(crate) const unsafe fn build() -> &'static bindings::dev_pm_ops {
+ &Self::VTABLE
+ }
+}
+
+/// Implements the [`Operations`] trait as no-ops.
+///
+/// This is useful when one doesn't want to provide the implementation of any power-manager related
+/// operation.
+pub struct NoOperations<T: PointerWrapper>(PhantomData<T>);
+
+impl<T: PointerWrapper + Send + Sync> Operations for NoOperations<T> {
+ type Data = T;
+}
+
+// SAFETY: `NoOperation` provides no functionality, it is safe to send a reference to it to
+// different threads.
+unsafe impl<T: PointerWrapper> Sync for NoOperations<T> {}
+
+// SAFETY: `NoOperation` provides no functionality, it is safe to send it to different threads.
+unsafe impl<T: PointerWrapper> Send for NoOperations<T> {}
diff --git a/rust/kernel/prelude.rs b/rust/kernel/prelude.rs
new file mode 100644
index 000000000000..26f8af9e16ab
--- /dev/null
+++ b/rust/kernel/prelude.rs
@@ -0,0 +1,36 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! The `kernel` prelude.
+//!
+//! These are the most common items used by Rust code in the kernel,
+//! intended to be imported by all Rust code, for convenience.
+//!
+//! # Examples
+//!
+//! ```
+//! use kernel::prelude::*;
+//! ```
+
+pub use core::pin::Pin;
+
+pub use alloc::{boxed::Box, string::String, vec::Vec};
+
+pub use macros::{module, vtable};
+
+pub use super::build_assert;
+
+pub use super::{
+ dbg, dev_alert, dev_crit, dev_dbg, dev_emerg, dev_err, dev_info, dev_notice, dev_warn, fmt,
+ pr_alert, pr_crit, pr_debug, pr_emerg, pr_err, pr_info, pr_notice, pr_warn,
+};
+
+pub use super::{module_fs, module_misc_device};
+
+#[cfg(CONFIG_ARM_AMBA)]
+pub use super::module_amba_driver;
+
+pub use super::static_assert;
+
+pub use super::{error::code::*, Error, Result};
+
+pub use super::{str::CStr, ARef, ThisModule};
diff --git a/rust/kernel/print.rs b/rust/kernel/print.rs
new file mode 100644
index 000000000000..92541efc7e22
--- /dev/null
+++ b/rust/kernel/print.rs
@@ -0,0 +1,406 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Printing facilities.
+//!
+//! C header: [`include/linux/printk.h`](../../../../include/linux/printk.h)
+//!
+//! Reference: <https://www.kernel.org/doc/html/latest/core-api/printk-basics.html>
+
+use core::{
+ ffi::{c_char, c_void},
+ fmt,
+};
+
+use crate::str::RawFormatter;
+
+#[cfg(CONFIG_PRINTK)]
+use crate::bindings;
+
+// Called from `vsprintf` with format specifier `%pA`.
+#[no_mangle]
+unsafe fn rust_fmt_argument(buf: *mut c_char, end: *mut c_char, ptr: *const c_void) -> *mut c_char {
+ use fmt::Write;
+ // SAFETY: The C contract guarantees that `buf` is valid if it's less than `end`.
+ let mut w = unsafe { RawFormatter::from_ptrs(buf.cast(), end.cast()) };
+ let _ = w.write_fmt(unsafe { *(ptr as *const fmt::Arguments<'_>) });
+ w.pos().cast()
+}
+
+/// Format strings.
+///
+/// Public but hidden since it should only be used from public macros.
+#[doc(hidden)]
+pub mod format_strings {
+ use crate::bindings;
+
+ /// The length we copy from the `KERN_*` kernel prefixes.
+ const LENGTH_PREFIX: usize = 2;
+
+ /// The length of the fixed format strings.
+ pub const LENGTH: usize = 10;
+
+ /// Generates a fixed format string for the kernel's [`_printk`].
+ ///
+ /// The format string is always the same for a given level, i.e. for a
+ /// given `prefix`, which are the kernel's `KERN_*` constants.
+ ///
+ /// [`_printk`]: ../../../../include/linux/printk.h
+ const fn generate(is_cont: bool, prefix: &[u8; 3]) -> [u8; LENGTH] {
+ // Ensure the `KERN_*` macros are what we expect.
+ assert!(prefix[0] == b'\x01');
+ if is_cont {
+ assert!(prefix[1] == b'c');
+ } else {
+ assert!(prefix[1] >= b'0' && prefix[1] <= b'7');
+ }
+ assert!(prefix[2] == b'\x00');
+
+ let suffix: &[u8; LENGTH - LENGTH_PREFIX] = if is_cont {
+ b"%pA\0\0\0\0\0"
+ } else {
+ b"%s: %pA\0"
+ };
+
+ [
+ prefix[0], prefix[1], suffix[0], suffix[1], suffix[2], suffix[3], suffix[4], suffix[5],
+ suffix[6], suffix[7],
+ ]
+ }
+
+ // Generate the format strings at compile-time.
+ //
+ // This avoids the compiler generating the contents on the fly in the stack.
+ //
+ // Furthermore, `static` instead of `const` is used to share the strings
+ // for all the kernel.
+ pub static EMERG: [u8; LENGTH] = generate(false, bindings::KERN_EMERG);
+ pub static ALERT: [u8; LENGTH] = generate(false, bindings::KERN_ALERT);
+ pub static CRIT: [u8; LENGTH] = generate(false, bindings::KERN_CRIT);
+ pub static ERR: [u8; LENGTH] = generate(false, bindings::KERN_ERR);
+ pub static WARNING: [u8; LENGTH] = generate(false, bindings::KERN_WARNING);
+ pub static NOTICE: [u8; LENGTH] = generate(false, bindings::KERN_NOTICE);
+ pub static INFO: [u8; LENGTH] = generate(false, bindings::KERN_INFO);
+ pub static DEBUG: [u8; LENGTH] = generate(false, bindings::KERN_DEBUG);
+ pub static CONT: [u8; LENGTH] = generate(true, bindings::KERN_CONT);
+}
+
+/// Prints a message via the kernel's [`_printk`].
+///
+/// Public but hidden since it should only be used from public macros.
+///
+/// # Safety
+///
+/// The format string must be one of the ones in [`format_strings`], and
+/// the module name must be null-terminated.
+///
+/// [`_printk`]: ../../../../include/linux/_printk.h
+#[doc(hidden)]
+#[cfg_attr(not(CONFIG_PRINTK), allow(unused_variables))]
+pub unsafe fn call_printk(
+ format_string: &[u8; format_strings::LENGTH],
+ module_name: &[u8],
+ args: fmt::Arguments<'_>,
+) {
+ // `_printk` does not seem to fail in any path.
+ #[cfg(CONFIG_PRINTK)]
+ unsafe {
+ bindings::_printk(
+ format_string.as_ptr() as _,
+ module_name.as_ptr(),
+ &args as *const _ as *const c_void,
+ );
+ }
+}
+
+/// Prints a message via the kernel's [`_printk`] for the `CONT` level.
+///
+/// Public but hidden since it should only be used from public macros.
+///
+/// [`_printk`]: ../../../../include/linux/printk.h
+#[doc(hidden)]
+#[cfg_attr(not(CONFIG_PRINTK), allow(unused_variables))]
+pub fn call_printk_cont(args: fmt::Arguments<'_>) {
+ // `_printk` does not seem to fail in any path.
+ //
+ // SAFETY: The format string is fixed.
+ #[cfg(CONFIG_PRINTK)]
+ unsafe {
+ bindings::_printk(
+ format_strings::CONT.as_ptr() as _,
+ &args as *const _ as *const c_void,
+ );
+ }
+}
+
+/// Performs formatting and forwards the string to [`call_printk`].
+///
+/// Public but hidden since it should only be used from public macros.
+#[doc(hidden)]
+#[cfg(not(testlib))]
+#[macro_export]
+#[allow(clippy::crate_in_macro_def)]
+macro_rules! print_macro (
+ // The non-continuation cases (most of them, e.g. `INFO`).
+ ($format_string:path, false, $($arg:tt)+) => (
+ // SAFETY: This hidden macro should only be called by the documented
+ // printing macros which ensure the format string is one of the fixed
+ // ones. All `__LOG_PREFIX`s are null-terminated as they are generated
+ // by the `module!` proc macro or fixed values defined in a kernel
+ // crate.
+ unsafe {
+ $crate::print::call_printk(
+ &$format_string,
+ crate::__LOG_PREFIX,
+ format_args!($($arg)+),
+ );
+ }
+ );
+
+ // The `CONT` case.
+ ($format_string:path, true, $($arg:tt)+) => (
+ $crate::print::call_printk_cont(
+ format_args!($($arg)+),
+ );
+ );
+);
+
+/// Stub for doctests
+#[cfg(testlib)]
+#[macro_export]
+macro_rules! print_macro (
+ ($format_string:path, $e:expr, $($arg:tt)+) => (
+ ()
+ );
+);
+
+// We could use a macro to generate these macros. However, doing so ends
+// up being a bit ugly: it requires the dollar token trick to escape `$` as
+// well as playing with the `doc` attribute. Furthermore, they cannot be easily
+// imported in the prelude due to [1]. So, for the moment, we just write them
+// manually, like in the C side; while keeping most of the logic in another
+// macro, i.e. [`print_macro`].
+//
+// [1]: https://github.com/rust-lang/rust/issues/52234
+
+/// Prints an emergency-level message (level 0).
+///
+/// Use this level if the system is unusable.
+///
+/// Equivalent to the kernel's [`pr_emerg`] macro.
+///
+/// Mimics the interface of [`std::print!`]. See [`core::fmt`] and
+/// [`alloc::format!`] for information about the formatting syntax.
+///
+/// [`pr_emerg`]: https://www.kernel.org/doc/html/latest/core-api/printk-basics.html#c.pr_emerg
+/// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
+///
+/// # Examples
+///
+/// ```
+/// pr_emerg!("hello {}\n", "there");
+/// ```
+#[macro_export]
+macro_rules! pr_emerg (
+ ($($arg:tt)*) => (
+ $crate::print_macro!($crate::print::format_strings::EMERG, false, $($arg)*)
+ )
+);
+
+/// Prints an alert-level message (level 1).
+///
+/// Use this level if action must be taken immediately.
+///
+/// Equivalent to the kernel's [`pr_alert`] macro.
+///
+/// Mimics the interface of [`std::print!`]. See [`core::fmt`] and
+/// [`alloc::format!`] for information about the formatting syntax.
+///
+/// [`pr_alert`]: https://www.kernel.org/doc/html/latest/core-api/printk-basics.html#c.pr_alert
+/// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
+///
+/// # Examples
+///
+/// ```
+/// pr_alert!("hello {}\n", "there");
+/// ```
+#[macro_export]
+macro_rules! pr_alert (
+ ($($arg:tt)*) => (
+ $crate::print_macro!($crate::print::format_strings::ALERT, false, $($arg)*)
+ )
+);
+
+/// Prints a critical-level message (level 2).
+///
+/// Use this level for critical conditions.
+///
+/// Equivalent to the kernel's [`pr_crit`] macro.
+///
+/// Mimics the interface of [`std::print!`]. See [`core::fmt`] and
+/// [`alloc::format!`] for information about the formatting syntax.
+///
+/// [`pr_crit`]: https://www.kernel.org/doc/html/latest/core-api/printk-basics.html#c.pr_crit
+/// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
+///
+/// # Examples
+///
+/// ```
+/// pr_crit!("hello {}\n", "there");
+/// ```
+#[macro_export]
+macro_rules! pr_crit (
+ ($($arg:tt)*) => (
+ $crate::print_macro!($crate::print::format_strings::CRIT, false, $($arg)*)
+ )
+);
+
+/// Prints an error-level message (level 3).
+///
+/// Use this level for error conditions.
+///
+/// Equivalent to the kernel's [`pr_err`] macro.
+///
+/// Mimics the interface of [`std::print!`]. See [`core::fmt`] and
+/// [`alloc::format!`] for information about the formatting syntax.
+///
+/// [`pr_err`]: https://www.kernel.org/doc/html/latest/core-api/printk-basics.html#c.pr_err
+/// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
+///
+/// # Examples
+///
+/// ```
+/// pr_err!("hello {}\n", "there");
+/// ```
+#[macro_export]
+macro_rules! pr_err (
+ ($($arg:tt)*) => (
+ $crate::print_macro!($crate::print::format_strings::ERR, false, $($arg)*)
+ )
+);
+
+/// Prints a warning-level message (level 4).
+///
+/// Use this level for warning conditions.
+///
+/// Equivalent to the kernel's [`pr_warn`] macro.
+///
+/// Mimics the interface of [`std::print!`]. See [`core::fmt`] and
+/// [`alloc::format!`] for information about the formatting syntax.
+///
+/// [`pr_warn`]: https://www.kernel.org/doc/html/latest/core-api/printk-basics.html#c.pr_warn
+/// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
+///
+/// # Examples
+///
+/// ```
+/// pr_warn!("hello {}\n", "there");
+/// ```
+#[macro_export]
+macro_rules! pr_warn (
+ ($($arg:tt)*) => (
+ $crate::print_macro!($crate::print::format_strings::WARNING, false, $($arg)*)
+ )
+);
+
+/// Prints a notice-level message (level 5).
+///
+/// Use this level for normal but significant conditions.
+///
+/// Equivalent to the kernel's [`pr_notice`] macro.
+///
+/// Mimics the interface of [`std::print!`]. See [`core::fmt`] and
+/// [`alloc::format!`] for information about the formatting syntax.
+///
+/// [`pr_notice`]: https://www.kernel.org/doc/html/latest/core-api/printk-basics.html#c.pr_notice
+/// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
+///
+/// # Examples
+///
+/// ```
+/// pr_notice!("hello {}\n", "there");
+/// ```
+#[macro_export]
+macro_rules! pr_notice (
+ ($($arg:tt)*) => (
+ $crate::print_macro!($crate::print::format_strings::NOTICE, false, $($arg)*)
+ )
+);
+
+/// Prints an info-level message (level 6).
+///
+/// Use this level for informational messages.
+///
+/// Equivalent to the kernel's [`pr_info`] macro.
+///
+/// Mimics the interface of [`std::print!`]. See [`core::fmt`] and
+/// [`alloc::format!`] for information about the formatting syntax.
+///
+/// [`pr_info`]: https://www.kernel.org/doc/html/latest/core-api/printk-basics.html#c.pr_info
+/// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
+///
+/// # Examples
+///
+/// ```
+/// pr_info!("hello {}\n", "there");
+/// ```
+#[macro_export]
+#[doc(alias = "print")]
+macro_rules! pr_info (
+ ($($arg:tt)*) => (
+ $crate::print_macro!($crate::print::format_strings::INFO, false, $($arg)*)
+ )
+);
+
+/// Prints a debug-level message (level 7).
+///
+/// Use this level for debug messages.
+///
+/// Equivalent to the kernel's [`pr_debug`] macro, except that it doesn't support dynamic debug
+/// yet.
+///
+/// Mimics the interface of [`std::print!`]. See [`core::fmt`] and
+/// [`alloc::format!`] for information about the formatting syntax.
+///
+/// [`pr_debug`]: https://www.kernel.org/doc/html/latest/core-api/printk-basics.html#c.pr_debug
+/// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
+///
+/// # Examples
+///
+/// ```
+/// pr_debug!("hello {}\n", "there");
+/// ```
+#[macro_export]
+#[doc(alias = "print")]
+macro_rules! pr_debug (
+ ($($arg:tt)*) => (
+ if cfg!(debug_assertions) {
+ $crate::print_macro!($crate::print::format_strings::DEBUG, false, $($arg)*)
+ }
+ )
+);
+
+/// Continues a previous log message in the same line.
+///
+/// Use only when continuing a previous `pr_*!` macro (e.g. [`pr_info!`]).
+///
+/// Equivalent to the kernel's [`pr_cont`] macro.
+///
+/// Mimics the interface of [`std::print!`]. See [`core::fmt`] and
+/// [`alloc::format!`] for information about the formatting syntax.
+///
+/// [`pr_cont`]: https://www.kernel.org/doc/html/latest/core-api/printk-basics.html#c.pr_cont
+/// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::pr_cont;
+/// pr_info!("hello");
+/// pr_cont!(" {}\n", "there");
+/// ```
+#[macro_export]
+macro_rules! pr_cont (
+ ($($arg:tt)*) => (
+ $crate::print_macro!($crate::print::format_strings::CONT, true, $($arg)*)
+ )
+);
diff --git a/rust/kernel/random.rs b/rust/kernel/random.rs
new file mode 100644
index 000000000000..c30dd675d6a0
--- /dev/null
+++ b/rust/kernel/random.rs
@@ -0,0 +1,42 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Random numbers.
+//!
+//! C header: [`include/linux/random.h`](../../../../include/linux/random.h)
+
+use crate::{bindings, error::code::*, Error, Result};
+
+/// Fills a byte slice with random bytes generated from the kernel's CSPRNG.
+///
+/// Ensures that the CSPRNG has been seeded before generating any random bytes,
+/// and will block until it is ready.
+pub fn getrandom(dest: &mut [u8]) -> Result {
+ let res = unsafe { bindings::wait_for_random_bytes() };
+ if res != 0 {
+ return Err(Error::from_kernel_errno(res));
+ }
+
+ unsafe {
+ bindings::get_random_bytes(dest.as_mut_ptr() as *mut core::ffi::c_void, dest.len());
+ }
+ Ok(())
+}
+
+/// Fills a byte slice with random bytes generated from the kernel's CSPRNG.
+///
+/// If the CSPRNG is not yet seeded, returns an `Err(EAGAIN)` immediately.
+pub fn getrandom_nonblock(dest: &mut [u8]) -> Result {
+ if !unsafe { bindings::rng_is_initialized() } {
+ return Err(EAGAIN);
+ }
+ getrandom(dest)
+}
+
+/// Contributes the contents of a byte slice to the kernel's entropy pool.
+///
+/// Does *not* credit the kernel entropy counter though.
+pub fn add_randomness(data: &[u8]) {
+ unsafe {
+ bindings::add_device_randomness(data.as_ptr() as *const core::ffi::c_void, data.len());
+ }
+}
diff --git a/rust/kernel/raw_list.rs b/rust/kernel/raw_list.rs
new file mode 100644
index 000000000000..267b21709c29
--- /dev/null
+++ b/rust/kernel/raw_list.rs
@@ -0,0 +1,361 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Raw lists.
+//!
+//! TODO: This module is a work in progress.
+
+use core::{
+ cell::UnsafeCell,
+ ptr,
+ ptr::NonNull,
+ sync::atomic::{AtomicBool, Ordering},
+};
+
+/// A descriptor of list elements.
+///
+/// It describes the type of list elements and provides a function to determine how to get the
+/// links to be used on a list.
+///
+/// A type that may be in multiple lists simultaneously needs to implement one of these for each
+/// simultaneous list.
+pub trait GetLinks {
+ /// The type of the entries in the list.
+ type EntryType: ?Sized;
+
+ /// Returns the links to be used when linking an entry within a list.
+ fn get_links(data: &Self::EntryType) -> &Links<Self::EntryType>;
+}
+
+/// The links used to link an object on a linked list.
+///
+/// Instances of this type are usually embedded in structures and returned in calls to
+/// [`GetLinks::get_links`].
+pub struct Links<T: ?Sized> {
+ inserted: AtomicBool,
+ entry: UnsafeCell<ListEntry<T>>,
+}
+
+impl<T: ?Sized> Links<T> {
+ /// Constructs a new [`Links`] instance that isn't inserted on any lists yet.
+ pub fn new() -> Self {
+ Self {
+ inserted: AtomicBool::new(false),
+ entry: UnsafeCell::new(ListEntry::new()),
+ }
+ }
+
+ fn acquire_for_insertion(&self) -> bool {
+ self.inserted
+ .compare_exchange(false, true, Ordering::Acquire, Ordering::Relaxed)
+ .is_ok()
+ }
+
+ fn release_after_removal(&self) {
+ self.inserted.store(false, Ordering::Release);
+ }
+}
+
+impl<T: ?Sized> Default for Links<T> {
+ fn default() -> Self {
+ Self::new()
+ }
+}
+
+struct ListEntry<T: ?Sized> {
+ next: Option<NonNull<T>>,
+ prev: Option<NonNull<T>>,
+}
+
+impl<T: ?Sized> ListEntry<T> {
+ fn new() -> Self {
+ Self {
+ next: None,
+ prev: None,
+ }
+ }
+}
+
+/// A linked list.
+///
+/// # Invariants
+///
+/// The links of objects added to a list are owned by the list.
+pub(crate) struct RawList<G: GetLinks> {
+ head: Option<NonNull<G::EntryType>>,
+}
+
+impl<G: GetLinks> RawList<G> {
+ pub(crate) fn new() -> Self {
+ Self { head: None }
+ }
+
+ pub(crate) fn is_empty(&self) -> bool {
+ self.head.is_none()
+ }
+
+ fn insert_after_priv(
+ &mut self,
+ existing: &G::EntryType,
+ new_entry: &mut ListEntry<G::EntryType>,
+ new_ptr: Option<NonNull<G::EntryType>>,
+ ) {
+ {
+ // SAFETY: It's safe to get the previous entry of `existing` because the list cannot
+ // change.
+ let existing_links = unsafe { &mut *G::get_links(existing).entry.get() };
+ new_entry.next = existing_links.next;
+ existing_links.next = new_ptr;
+ }
+
+ new_entry.prev = Some(NonNull::from(existing));
+
+ // SAFETY: It's safe to get the next entry of `existing` because the list cannot change.
+ let next_links =
+ unsafe { &mut *G::get_links(new_entry.next.unwrap().as_ref()).entry.get() };
+ next_links.prev = new_ptr;
+ }
+
+ /// Inserts the given object after `existing`.
+ ///
+ /// # Safety
+ ///
+ /// Callers must ensure that `existing` points to a valid entry that is on the list.
+ pub(crate) unsafe fn insert_after(
+ &mut self,
+ existing: &G::EntryType,
+ new: &G::EntryType,
+ ) -> bool {
+ let links = G::get_links(new);
+ if !links.acquire_for_insertion() {
+ // Nothing to do if already inserted.
+ return false;
+ }
+
+ // SAFETY: The links are now owned by the list, so it is safe to get a mutable reference.
+ let new_entry = unsafe { &mut *links.entry.get() };
+ self.insert_after_priv(existing, new_entry, Some(NonNull::from(new)));
+ true
+ }
+
+ fn push_back_internal(&mut self, new: &G::EntryType) -> bool {
+ let links = G::get_links(new);
+ if !links.acquire_for_insertion() {
+ // Nothing to do if already inserted.
+ return false;
+ }
+
+ // SAFETY: The links are now owned by the list, so it is safe to get a mutable reference.
+ let new_entry = unsafe { &mut *links.entry.get() };
+ let new_ptr = Some(NonNull::from(new));
+ match self.back() {
+ // SAFETY: `back` is valid as the list cannot change.
+ Some(back) => self.insert_after_priv(unsafe { back.as_ref() }, new_entry, new_ptr),
+ None => {
+ self.head = new_ptr;
+ new_entry.next = new_ptr;
+ new_entry.prev = new_ptr;
+ }
+ }
+ true
+ }
+
+ pub(crate) unsafe fn push_back(&mut self, new: &G::EntryType) -> bool {
+ self.push_back_internal(new)
+ }
+
+ fn remove_internal(&mut self, data: &G::EntryType) -> bool {
+ let links = G::get_links(data);
+
+ // SAFETY: The links are now owned by the list, so it is safe to get a mutable reference.
+ let entry = unsafe { &mut *links.entry.get() };
+ let next = if let Some(next) = entry.next {
+ next
+ } else {
+ // Nothing to do if the entry is not on the list.
+ return false;
+ };
+
+ if ptr::eq(data, next.as_ptr()) {
+ // We're removing the only element.
+ self.head = None
+ } else {
+ // Update the head if we're removing it.
+ if let Some(raw_head) = self.head {
+ if ptr::eq(data, raw_head.as_ptr()) {
+ self.head = Some(next);
+ }
+ }
+
+ // SAFETY: It's safe to get the previous entry because the list cannot change.
+ unsafe { &mut *G::get_links(entry.prev.unwrap().as_ref()).entry.get() }.next =
+ entry.next;
+
+ // SAFETY: It's safe to get the next entry because the list cannot change.
+ unsafe { &mut *G::get_links(next.as_ref()).entry.get() }.prev = entry.prev;
+ }
+
+ // Reset the links of the element we're removing so that we know it's not on any list.
+ entry.next = None;
+ entry.prev = None;
+ links.release_after_removal();
+ true
+ }
+
+ /// Removes the given entry.
+ ///
+ /// # Safety
+ ///
+ /// Callers must ensure that `data` is either on this list or in no list. It being on another
+ /// list leads to memory unsafety.
+ pub(crate) unsafe fn remove(&mut self, data: &G::EntryType) -> bool {
+ self.remove_internal(data)
+ }
+
+ fn pop_front_internal(&mut self) -> Option<NonNull<G::EntryType>> {
+ let head = self.head?;
+ // SAFETY: The head is on the list as we just got it from there and it cannot change.
+ unsafe { self.remove(head.as_ref()) };
+ Some(head)
+ }
+
+ pub(crate) fn pop_front(&mut self) -> Option<NonNull<G::EntryType>> {
+ self.pop_front_internal()
+ }
+
+ pub(crate) fn front(&self) -> Option<NonNull<G::EntryType>> {
+ self.head
+ }
+
+ pub(crate) fn back(&self) -> Option<NonNull<G::EntryType>> {
+ // SAFETY: The links of head are owned by the list, so it is safe to get a reference.
+ unsafe { &*G::get_links(self.head?.as_ref()).entry.get() }.prev
+ }
+
+ pub(crate) fn cursor_front(&self) -> Cursor<'_, G> {
+ Cursor::new(self, self.front())
+ }
+
+ pub(crate) fn cursor_front_mut(&mut self) -> CursorMut<'_, G> {
+ CursorMut::new(self, self.front())
+ }
+}
+
+struct CommonCursor<G: GetLinks> {
+ cur: Option<NonNull<G::EntryType>>,
+}
+
+impl<G: GetLinks> CommonCursor<G> {
+ fn new(cur: Option<NonNull<G::EntryType>>) -> Self {
+ Self { cur }
+ }
+
+ fn move_next(&mut self, list: &RawList<G>) {
+ match self.cur.take() {
+ None => self.cur = list.head,
+ Some(cur) => {
+ if let Some(head) = list.head {
+ // SAFETY: We have a shared ref to the linked list, so the links can't change.
+ let links = unsafe { &*G::get_links(cur.as_ref()).entry.get() };
+ if links.next.unwrap() != head {
+ self.cur = links.next;
+ }
+ }
+ }
+ }
+ }
+
+ fn move_prev(&mut self, list: &RawList<G>) {
+ match list.head {
+ None => self.cur = None,
+ Some(head) => {
+ let next = match self.cur.take() {
+ None => head,
+ Some(cur) => {
+ if cur == head {
+ return;
+ }
+ cur
+ }
+ };
+ // SAFETY: There's a shared ref to the list, so the links can't change.
+ let links = unsafe { &*G::get_links(next.as_ref()).entry.get() };
+ self.cur = links.prev;
+ }
+ }
+ }
+}
+
+/// A list cursor that allows traversing a linked list and inspecting elements.
+pub struct Cursor<'a, G: GetLinks> {
+ cursor: CommonCursor<G>,
+ list: &'a RawList<G>,
+}
+
+impl<'a, G: GetLinks> Cursor<'a, G> {
+ fn new(list: &'a RawList<G>, cur: Option<NonNull<G::EntryType>>) -> Self {
+ Self {
+ list,
+ cursor: CommonCursor::new(cur),
+ }
+ }
+
+ /// Returns the element the cursor is currently positioned on.
+ pub fn current(&self) -> Option<&'a G::EntryType> {
+ let cur = self.cursor.cur?;
+ // SAFETY: Objects must be kept alive while on the list.
+ Some(unsafe { &*cur.as_ptr() })
+ }
+
+ /// Moves the cursor to the next element.
+ pub fn move_next(&mut self) {
+ self.cursor.move_next(self.list);
+ }
+}
+
+pub(crate) struct CursorMut<'a, G: GetLinks> {
+ cursor: CommonCursor<G>,
+ list: &'a mut RawList<G>,
+}
+
+impl<'a, G: GetLinks> CursorMut<'a, G> {
+ fn new(list: &'a mut RawList<G>, cur: Option<NonNull<G::EntryType>>) -> Self {
+ Self {
+ list,
+ cursor: CommonCursor::new(cur),
+ }
+ }
+
+ pub(crate) fn current(&mut self) -> Option<&mut G::EntryType> {
+ let cur = self.cursor.cur?;
+ // SAFETY: Objects must be kept alive while on the list.
+ Some(unsafe { &mut *cur.as_ptr() })
+ }
+
+ /// Removes the entry the cursor is pointing to and advances the cursor to the next entry. It
+ /// returns a raw pointer to the removed element (if one is removed).
+ pub(crate) fn remove_current(&mut self) -> Option<NonNull<G::EntryType>> {
+ let entry = self.cursor.cur?;
+ self.cursor.move_next(self.list);
+ // SAFETY: The entry is on the list as we just got it from there and it cannot change.
+ unsafe { self.list.remove(entry.as_ref()) };
+ Some(entry)
+ }
+
+ pub(crate) fn peek_next(&mut self) -> Option<&mut G::EntryType> {
+ let mut new = CommonCursor::new(self.cursor.cur);
+ new.move_next(self.list);
+ // SAFETY: Objects must be kept alive while on the list.
+ Some(unsafe { &mut *new.cur?.as_ptr() })
+ }
+
+ pub(crate) fn peek_prev(&mut self) -> Option<&mut G::EntryType> {
+ let mut new = CommonCursor::new(self.cursor.cur);
+ new.move_prev(self.list);
+ // SAFETY: Objects must be kept alive while on the list.
+ Some(unsafe { &mut *new.cur?.as_ptr() })
+ }
+
+ pub(crate) fn move_next(&mut self) {
+ self.cursor.move_next(self.list);
+ }
+}
diff --git a/rust/kernel/rbtree.rs b/rust/kernel/rbtree.rs
new file mode 100644
index 000000000000..a30739cc6839
--- /dev/null
+++ b/rust/kernel/rbtree.rs
@@ -0,0 +1,563 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Red-black trees.
+//!
+//! C header: [`include/linux/rbtree.h`](../../../../include/linux/rbtree.h)
+//!
+//! Reference: <https://www.kernel.org/doc/html/latest/core-api/rbtree.html>
+
+use crate::{bindings, Result};
+use alloc::boxed::Box;
+use core::{
+ cmp::{Ord, Ordering},
+ iter::{IntoIterator, Iterator},
+ marker::PhantomData,
+ mem::MaybeUninit,
+ ptr::{addr_of_mut, NonNull},
+};
+
+struct Node<K, V> {
+ links: bindings::rb_node,
+ key: K,
+ value: V,
+}
+
+/// A red-black tree with owned nodes.
+///
+/// It is backed by the kernel C red-black trees.
+///
+/// # Invariants
+///
+/// Non-null parent/children pointers stored in instances of the `rb_node` C struct are always
+/// valid, and pointing to a field of our internal representation of a node.
+///
+/// # Examples
+///
+/// In the example below we do several operations on a tree. We note that insertions may fail if
+/// the system is out of memory.
+///
+/// ```
+/// use kernel::rbtree::RBTree;
+///
+/// # fn test() -> Result {
+/// // Create a new tree.
+/// let mut tree = RBTree::new();
+///
+/// // Insert three elements.
+/// tree.try_insert(20, 200)?;
+/// tree.try_insert(10, 100)?;
+/// tree.try_insert(30, 300)?;
+///
+/// // Check the nodes we just inserted.
+/// {
+/// let mut iter = tree.iter();
+/// assert_eq!(iter.next().unwrap(), (&10, &100));
+/// assert_eq!(iter.next().unwrap(), (&20, &200));
+/// assert_eq!(iter.next().unwrap(), (&30, &300));
+/// assert!(iter.next().is_none());
+/// }
+///
+/// // Print all elements.
+/// for (key, value) in &tree {
+/// pr_info!("{} = {}\n", key, value);
+/// }
+///
+/// // Replace one of the elements.
+/// tree.try_insert(10, 1000)?;
+///
+/// // Check that the tree reflects the replacement.
+/// {
+/// let mut iter = tree.iter();
+/// assert_eq!(iter.next().unwrap(), (&10, &1000));
+/// assert_eq!(iter.next().unwrap(), (&20, &200));
+/// assert_eq!(iter.next().unwrap(), (&30, &300));
+/// assert!(iter.next().is_none());
+/// }
+///
+/// // Change the value of one of the elements.
+/// *tree.get_mut(&30).unwrap() = 3000;
+///
+/// // Check that the tree reflects the update.
+/// {
+/// let mut iter = tree.iter();
+/// assert_eq!(iter.next().unwrap(), (&10, &1000));
+/// assert_eq!(iter.next().unwrap(), (&20, &200));
+/// assert_eq!(iter.next().unwrap(), (&30, &3000));
+/// assert!(iter.next().is_none());
+/// }
+///
+/// // Remove an element.
+/// tree.remove(&10);
+///
+/// // Check that the tree reflects the removal.
+/// {
+/// let mut iter = tree.iter();
+/// assert_eq!(iter.next().unwrap(), (&20, &200));
+/// assert_eq!(iter.next().unwrap(), (&30, &3000));
+/// assert!(iter.next().is_none());
+/// }
+///
+/// // Update all values.
+/// for value in tree.values_mut() {
+/// *value *= 10;
+/// }
+///
+/// // Check that the tree reflects the changes to values.
+/// {
+/// let mut iter = tree.iter();
+/// assert_eq!(iter.next().unwrap(), (&20, &2000));
+/// assert_eq!(iter.next().unwrap(), (&30, &30000));
+/// assert!(iter.next().is_none());
+/// }
+///
+/// # Ok(())
+/// # }
+/// #
+/// # assert_eq!(test(), Ok(()));
+/// ```
+///
+/// In the example below, we first allocate a node, acquire a spinlock, then insert the node into
+/// the tree. This is useful when the insertion context does not allow sleeping, for example, when
+/// holding a spinlock.
+///
+/// ```
+/// use kernel::{rbtree::RBTree, sync::SpinLock};
+///
+/// fn insert_test(tree: &SpinLock<RBTree<u32, u32>>) -> Result {
+/// // Pre-allocate node. This may fail (as it allocates memory).
+/// let node = RBTree::try_allocate_node(10, 100)?;
+///
+/// // Insert node while holding the lock. It is guaranteed to succeed with no allocation
+/// // attempts.
+/// let mut guard = tree.lock();
+/// guard.insert(node);
+/// Ok(())
+/// }
+/// ```
+///
+/// In the example below, we reuse an existing node allocation from an element we removed.
+///
+/// ```
+/// use kernel::rbtree::RBTree;
+///
+/// # fn test() -> Result {
+/// // Create a new tree.
+/// let mut tree = RBTree::new();
+///
+/// // Insert three elements.
+/// tree.try_insert(20, 200)?;
+/// tree.try_insert(10, 100)?;
+/// tree.try_insert(30, 300)?;
+///
+/// // Check the nodes we just inserted.
+/// {
+/// let mut iter = tree.iter();
+/// assert_eq!(iter.next().unwrap(), (&10, &100));
+/// assert_eq!(iter.next().unwrap(), (&20, &200));
+/// assert_eq!(iter.next().unwrap(), (&30, &300));
+/// assert!(iter.next().is_none());
+/// }
+///
+/// // Remove a node, getting back ownership of it.
+/// let existing = tree.remove_node(&30).unwrap();
+///
+/// // Check that the tree reflects the removal.
+/// {
+/// let mut iter = tree.iter();
+/// assert_eq!(iter.next().unwrap(), (&10, &100));
+/// assert_eq!(iter.next().unwrap(), (&20, &200));
+/// assert!(iter.next().is_none());
+/// }
+///
+/// // Turn the node into a reservation so that we can reuse it with a different key/value.
+/// let reservation = existing.into_reservation();
+///
+/// // Insert a new node into the tree, reusing the previous allocation. This is guaranteed to
+/// // succeed (no memory allocations).
+/// tree.insert(reservation.into_node(15, 150));
+///
+/// // Check that the tree reflect the new insertion.
+/// {
+/// let mut iter = tree.iter();
+/// assert_eq!(iter.next().unwrap(), (&10, &100));
+/// assert_eq!(iter.next().unwrap(), (&15, &150));
+/// assert_eq!(iter.next().unwrap(), (&20, &200));
+/// assert!(iter.next().is_none());
+/// }
+///
+/// # Ok(())
+/// # }
+/// #
+/// # assert_eq!(test(), Ok(()));
+/// ```
+pub struct RBTree<K, V> {
+ root: bindings::rb_root,
+ _p: PhantomData<Node<K, V>>,
+}
+
+impl<K, V> RBTree<K, V> {
+ /// Creates a new and empty tree.
+ pub fn new() -> Self {
+ Self {
+ // INVARIANT: There are no nodes in the tree, so the invariant holds vacuously.
+ root: bindings::rb_root::default(),
+ _p: PhantomData,
+ }
+ }
+
+ /// Tries to insert a new value into the tree.
+ ///
+ /// It overwrites a node if one already exists with the same key and returns it (containing the
+ /// key/value pair). Returns [`None`] if a node with the same key didn't already exist.
+ ///
+ /// Returns an error if it cannot allocate memory for the new node.
+ pub fn try_insert(&mut self, key: K, value: V) -> Result<Option<RBTreeNode<K, V>>>
+ where
+ K: Ord,
+ {
+ Ok(self.insert(Self::try_allocate_node(key, value)?))
+ }
+
+ /// Allocates memory for a node to be eventually initialised and inserted into the tree via a
+ /// call to [`RBTree::insert`].
+ pub fn try_reserve_node() -> Result<RBTreeNodeReservation<K, V>> {
+ Ok(RBTreeNodeReservation {
+ node: Box::try_new(MaybeUninit::uninit())?,
+ })
+ }
+
+ /// Allocates and initialiases a node that can be inserted into the tree via
+ /// [`RBTree::insert`].
+ pub fn try_allocate_node(key: K, value: V) -> Result<RBTreeNode<K, V>> {
+ Ok(Self::try_reserve_node()?.into_node(key, value))
+ }
+
+ /// Inserts a new node into the tree.
+ ///
+ /// It overwrites a node if one already exists with the same key and returns it (containing the
+ /// key/value pair). Returns [`None`] if a node with the same key didn't already exist.
+ ///
+ /// This function always succeeds.
+ pub fn insert(&mut self, node: RBTreeNode<K, V>) -> Option<RBTreeNode<K, V>>
+ where
+ K: Ord,
+ {
+ let RBTreeNode { node } = node;
+ let node = Box::into_raw(node);
+ // SAFETY: `node` is valid at least until we call `Box::from_raw`, which only happens when
+ // the node is removed or replaced.
+ let node_links = unsafe { addr_of_mut!((*node).links) };
+ let mut new_link: &mut *mut bindings::rb_node = &mut self.root.rb_node;
+ let mut parent = core::ptr::null_mut();
+ while !new_link.is_null() {
+ let this = crate::container_of!(*new_link, Node<K, V>, links);
+
+ parent = *new_link;
+
+ // SAFETY: `this` is a non-null node so it is valid by the type invariants. `node` is
+ // valid until the node is removed.
+ match unsafe { (*node).key.cmp(&(*this).key) } {
+ // SAFETY: `parent` is a non-null node so it is valid by the type invariants.
+ Ordering::Less => new_link = unsafe { &mut (*parent).rb_left },
+ // SAFETY: `parent` is a non-null node so it is valid by the type invariants.
+ Ordering::Greater => new_link = unsafe { &mut (*parent).rb_right },
+ Ordering::Equal => {
+ // INVARIANT: We are replacing an existing node with a new one, which is valid.
+ // It remains valid because we "forgot" it with `Box::into_raw`.
+ // SAFETY: All pointers are non-null and valid (parent, despite the name, really
+ // is the node we're replacing).
+ unsafe { bindings::rb_replace_node(parent, node_links, &mut self.root) };
+
+ // INVARIANT: The node is being returned and the caller may free it, however,
+ // it was removed from the tree. So the invariants still hold.
+ return Some(RBTreeNode {
+ // SAFETY: `this` was a node in the tree, so it is valid.
+ node: unsafe { Box::from_raw(this as _) },
+ });
+ }
+ }
+ }
+
+ // INVARIANT: We are linking in a new node, which is valid. It remains valid because we
+ // "forgot" it with `Box::into_raw`.
+ // SAFETY: All pointers are non-null and valid (`*new_link` is null, but `new_link` is a
+ // mutable reference).
+ unsafe { bindings::rb_link_node(node_links, parent, new_link) };
+
+ // SAFETY: All pointers are valid. `node` has just been inserted into the tree.
+ unsafe { bindings::rb_insert_color(node_links, &mut self.root) };
+ None
+ }
+
+ /// Returns a node with the given key, if one exists.
+ fn find(&self, key: &K) -> Option<NonNull<Node<K, V>>>
+ where
+ K: Ord,
+ {
+ let mut node = self.root.rb_node;
+ while !node.is_null() {
+ let this = crate::container_of!(node, Node<K, V>, links);
+ // SAFETY: `this` is a non-null node so it is valid by the type invariants.
+ node = match key.cmp(unsafe { &(*this).key }) {
+ // SAFETY: `node` is a non-null node so it is valid by the type invariants.
+ Ordering::Less => unsafe { (*node).rb_left },
+ // SAFETY: `node` is a non-null node so it is valid by the type invariants.
+ Ordering::Greater => unsafe { (*node).rb_right },
+ Ordering::Equal => return NonNull::new(this as _),
+ }
+ }
+ None
+ }
+
+ /// Returns a reference to the value corresponding to the key.
+ pub fn get(&self, key: &K) -> Option<&V>
+ where
+ K: Ord,
+ {
+ // SAFETY: The `find` return value is a node in the tree, so it is valid.
+ self.find(key).map(|node| unsafe { &node.as_ref().value })
+ }
+
+ /// Returns a mutable reference to the value corresponding to the key.
+ pub fn get_mut(&mut self, key: &K) -> Option<&mut V>
+ where
+ K: Ord,
+ {
+ // SAFETY: The `find` return value is a node in the tree, so it is valid.
+ self.find(key)
+ .map(|mut node| unsafe { &mut node.as_mut().value })
+ }
+
+ /// Removes the node with the given key from the tree.
+ ///
+ /// It returns the node that was removed if one exists, or [`None`] otherwise.
+ pub fn remove_node(&mut self, key: &K) -> Option<RBTreeNode<K, V>>
+ where
+ K: Ord,
+ {
+ let mut node = self.find(key)?;
+
+ // SAFETY: The `find` return value is a node in the tree, so it is valid.
+ unsafe { bindings::rb_erase(&mut node.as_mut().links, &mut self.root) };
+
+ // INVARIANT: The node is being returned and the caller may free it, however, it was
+ // removed from the tree. So the invariants still hold.
+ Some(RBTreeNode {
+ // SAFETY: The `find` return value was a node in the tree, so it is valid.
+ node: unsafe { Box::from_raw(node.as_ptr()) },
+ })
+ }
+
+ /// Removes the node with the given key from the tree.
+ ///
+ /// It returns the value that was removed if one exists, or [`None`] otherwise.
+ pub fn remove(&mut self, key: &K) -> Option<V>
+ where
+ K: Ord,
+ {
+ let node = self.remove_node(key)?;
+ let RBTreeNode { node } = node;
+ let Node {
+ links: _,
+ key: _,
+ value,
+ } = *node;
+ Some(value)
+ }
+
+ /// Returns an iterator over the tree nodes, sorted by key.
+ pub fn iter(&self) -> RBTreeIterator<'_, K, V> {
+ RBTreeIterator {
+ _tree: PhantomData,
+ // SAFETY: `root` is valid as it's embedded in `self` and we have a valid `self`.
+ next: unsafe { bindings::rb_first(&self.root) },
+ }
+ }
+
+ /// Returns a mutable iterator over the tree nodes, sorted by key.
+ pub fn iter_mut(&mut self) -> RBTreeIteratorMut<'_, K, V> {
+ RBTreeIteratorMut {
+ _tree: PhantomData,
+ // SAFETY: `root` is valid as it's embedded in `self` and we have a valid `self`.
+ next: unsafe { bindings::rb_first(&self.root) },
+ }
+ }
+
+ /// Returns an iterator over the keys of the nodes in the tree, in sorted order.
+ pub fn keys(&self) -> impl Iterator<Item = &'_ K> {
+ self.iter().map(|(k, _)| k)
+ }
+
+ /// Returns an iterator over the values of the nodes in the tree, sorted by key.
+ pub fn values(&self) -> impl Iterator<Item = &'_ V> {
+ self.iter().map(|(_, v)| v)
+ }
+
+ /// Returns a mutable iterator over the values of the nodes in the tree, sorted by key.
+ pub fn values_mut(&mut self) -> impl Iterator<Item = &'_ mut V> {
+ self.iter_mut().map(|(_, v)| v)
+ }
+}
+
+impl<K, V> Default for RBTree<K, V> {
+ fn default() -> Self {
+ Self::new()
+ }
+}
+
+impl<K, V> Drop for RBTree<K, V> {
+ fn drop(&mut self) {
+ // SAFETY: `root` is valid as it's embedded in `self` and we have a valid `self`.
+ let mut next = unsafe { bindings::rb_first_postorder(&self.root) };
+
+ // INVARIANT: The loop invariant is that all tree nodes from `next` in postorder are valid.
+ while !next.is_null() {
+ let this = crate::container_of!(next, Node<K, V>, links);
+
+ // Find out what the next node is before disposing of the current one.
+ // SAFETY: `next` and all nodes in postorder are still valid.
+ next = unsafe { bindings::rb_next_postorder(next) };
+
+ // INVARIANT: This is the destructor, so we break the type invariant during clean-up,
+ // but it is not observable. The loop invariant is still maintained.
+ // SAFETY: `this` is valid per the loop invariant.
+ unsafe { Box::from_raw(this as *mut Node<K, V>) };
+ }
+ }
+}
+
+impl<'a, K, V> IntoIterator for &'a RBTree<K, V> {
+ type Item = (&'a K, &'a V);
+ type IntoIter = RBTreeIterator<'a, K, V>;
+
+ fn into_iter(self) -> Self::IntoIter {
+ self.iter()
+ }
+}
+
+/// An iterator over the nodes of a [`RBTree`].
+///
+/// Instances are created by calling [`RBTree::iter`].
+pub struct RBTreeIterator<'a, K, V> {
+ _tree: PhantomData<&'a RBTree<K, V>>,
+ next: *mut bindings::rb_node,
+}
+
+impl<'a, K, V> Iterator for RBTreeIterator<'a, K, V> {
+ type Item = (&'a K, &'a V);
+
+ fn next(&mut self) -> Option<Self::Item> {
+ if self.next.is_null() {
+ return None;
+ }
+
+ let cur = crate::container_of!(self.next, Node<K, V>, links);
+
+ // SAFETY: The reference to the tree used to create the iterator outlives the iterator, so
+ // the tree cannot change. By the tree invariant, all nodes are valid.
+ self.next = unsafe { bindings::rb_next(self.next) };
+
+ // SAFETY: By the same reasoning above, it is safe to dereference the node. Additionally,
+ // it is ok to return a reference to members because the iterator must outlive it.
+ Some(unsafe { (&(*cur).key, &(*cur).value) })
+ }
+}
+
+impl<'a, K, V> IntoIterator for &'a mut RBTree<K, V> {
+ type Item = (&'a K, &'a mut V);
+ type IntoIter = RBTreeIteratorMut<'a, K, V>;
+
+ fn into_iter(self) -> Self::IntoIter {
+ self.iter_mut()
+ }
+}
+
+/// A mutable iterator over the nodes of a [`RBTree`].
+///
+/// Instances are created by calling [`RBTree::iter_mut`].
+pub struct RBTreeIteratorMut<'a, K, V> {
+ _tree: PhantomData<&'a RBTree<K, V>>,
+ next: *mut bindings::rb_node,
+}
+
+impl<'a, K, V> Iterator for RBTreeIteratorMut<'a, K, V> {
+ type Item = (&'a K, &'a mut V);
+
+ fn next(&mut self) -> Option<Self::Item> {
+ if self.next.is_null() {
+ return None;
+ }
+
+ let cur = crate::container_of!(self.next, Node<K, V>, links) as *mut Node<K, V>;
+
+ // SAFETY: The reference to the tree used to create the iterator outlives the iterator, so
+ // the tree cannot change (except for the value of previous nodes, but those don't affect
+ // the iteration process). By the tree invariant, all nodes are valid.
+ self.next = unsafe { bindings::rb_next(self.next) };
+
+ // SAFETY: By the same reasoning above, it is safe to dereference the node. Additionally,
+ // it is ok to return a reference to members because the iterator must outlive it.
+ Some(unsafe { (&(*cur).key, &mut (*cur).value) })
+ }
+}
+
+/// A memory reservation for a red-black tree node.
+///
+/// It contains the memory needed to hold a node that can be inserted into a red-black tree. One
+/// can be obtained by directly allocating it ([`RBTree::try_reserve_node`]) or by "uninitialising"
+/// ([`RBTreeNode::into_reservation`]) an actual node (usually returned by some operation like
+/// removal from a tree).
+pub struct RBTreeNodeReservation<K, V> {
+ node: Box<MaybeUninit<Node<K, V>>>,
+}
+
+impl<K, V> RBTreeNodeReservation<K, V> {
+ /// Initialises a node reservation.
+ ///
+ /// It then becomes an [`RBTreeNode`] that can be inserted into a tree.
+ pub fn into_node(mut self, key: K, value: V) -> RBTreeNode<K, V> {
+ let node_ptr = self.node.as_mut_ptr();
+ // SAFETY: `node_ptr` is valid, and so are its fields.
+ unsafe { addr_of_mut!((*node_ptr).links).write(bindings::rb_node::default()) };
+ // SAFETY: `node_ptr` is valid, and so are its fields.
+ unsafe { addr_of_mut!((*node_ptr).key).write(key) };
+ // SAFETY: `node_ptr` is valid, and so are its fields.
+ unsafe { addr_of_mut!((*node_ptr).value).write(value) };
+ let raw = Box::into_raw(self.node);
+ RBTreeNode {
+ // SAFETY: The pointer came from a `MaybeUninit<Node>` whose fields have all been
+ // initialised. Additionally, it has the same layout as `Node`.
+ node: unsafe { Box::from_raw(raw as _) },
+ }
+ }
+}
+
+/// A red-black tree node.
+///
+/// The node is fully initialised (with key and value) and can be inserted into a tree without any
+/// extra allocations or failure paths.
+pub struct RBTreeNode<K, V> {
+ node: Box<Node<K, V>>,
+}
+
+impl<K, V> RBTreeNode<K, V> {
+ /// "Uninitialises" a node.
+ ///
+ /// It then becomes a reservation that can be re-initialised into a different node (i.e., with
+ /// a different key and/or value).
+ ///
+ /// The existing key and value are dropped in-place as part of this operation, that is, memory
+ /// may be freed (but only for the key/value; memory for the node itself is kept for reuse).
+ pub fn into_reservation(self) -> RBTreeNodeReservation<K, V> {
+ let raw = Box::into_raw(self.node);
+ let mut ret = RBTreeNodeReservation {
+ // SAFETY: The pointer came from a valid `Node`, which has the same layout as
+ // `MaybeUninit<Node>`.
+ node: unsafe { Box::from_raw(raw as _) },
+ };
+ // SAFETY: Although the type is `MaybeUninit<Node>`, we know it has been initialised
+ // because it came from a `Node`. So it is safe to drop it.
+ unsafe { core::ptr::drop_in_place(ret.node.as_mut_ptr()) };
+ ret
+ }
+}
diff --git a/rust/kernel/revocable.rs b/rust/kernel/revocable.rs
new file mode 100644
index 000000000000..1093c4d26026
--- /dev/null
+++ b/rust/kernel/revocable.rs
@@ -0,0 +1,425 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Revocable objects.
+//!
+//! The [`Revocable`] type wraps other types and allows access to them to be revoked. The existence
+//! of a [`RevocableGuard`] ensures that objects remain valid.
+
+use crate::{bindings, sync::rcu};
+use core::{
+ cell::UnsafeCell,
+ marker::PhantomData,
+ mem::MaybeUninit,
+ ops::Deref,
+ ptr::drop_in_place,
+ sync::atomic::{fence, AtomicBool, AtomicU32, Ordering},
+};
+
+/// An object that can become inaccessible at runtime.
+///
+/// Once access is revoked and all concurrent users complete (i.e., all existing instances of
+/// [`RevocableGuard`] are dropped), the wrapped object is also dropped.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::revocable::Revocable;
+///
+/// struct Example {
+/// a: u32,
+/// b: u32,
+/// }
+///
+/// fn add_two(v: &Revocable<Example>) -> Option<u32> {
+/// let guard = v.try_access()?;
+/// Some(guard.a + guard.b)
+/// }
+///
+/// let v = Revocable::new(Example { a: 10, b: 20 });
+/// assert_eq!(add_two(&v), Some(30));
+/// v.revoke();
+/// assert_eq!(add_two(&v), None);
+/// ```
+///
+/// Sample example as above, but explicitly using the rcu read side lock.
+///
+/// ```
+/// # use kernel::revocable::Revocable;
+/// use kernel::sync::rcu;
+///
+/// struct Example {
+/// a: u32,
+/// b: u32,
+/// }
+///
+/// fn add_two(v: &Revocable<Example>) -> Option<u32> {
+/// let guard = rcu::read_lock();
+/// let e = v.try_access_with_guard(&guard)?;
+/// Some(e.a + e.b)
+/// }
+///
+/// let v = Revocable::new(Example { a: 10, b: 20 });
+/// assert_eq!(add_two(&v), Some(30));
+/// v.revoke();
+/// assert_eq!(add_two(&v), None);
+/// ```
+pub struct Revocable<T> {
+ is_available: AtomicBool,
+ data: MaybeUninit<UnsafeCell<T>>,
+}
+
+// SAFETY: `Revocable` is `Send` if the wrapped object is also `Send`. This is because while the
+// functionality exposed by `Revocable` can be accessed from any thread/CPU, it is possible that
+// this isn't supported by the wrapped object.
+unsafe impl<T: Send> Send for Revocable<T> {}
+
+// SAFETY: `Revocable` is `Sync` if the wrapped object is both `Send` and `Sync`. We require `Send`
+// from the wrapped object as well because of `Revocable::revoke`, which can trigger the `Drop`
+// implementation of the wrapped object from an arbitrary thread.
+unsafe impl<T: Sync + Send> Sync for Revocable<T> {}
+
+impl<T> Revocable<T> {
+ /// Creates a new revocable instance of the given data.
+ pub const fn new(data: T) -> Self {
+ Self {
+ is_available: AtomicBool::new(true),
+ data: MaybeUninit::new(UnsafeCell::new(data)),
+ }
+ }
+
+ /// Tries to access the \[revocable\] wrapped object.
+ ///
+ /// Returns `None` if the object has been revoked and is therefore no longer accessible.
+ ///
+ /// Returns a guard that gives access to the object otherwise; the object is guaranteed to
+ /// remain accessible while the guard is alive. In such cases, callers are not allowed to sleep
+ /// because another CPU may be waiting to complete the revocation of this object.
+ pub fn try_access(&self) -> Option<RevocableGuard<'_, T>> {
+ let guard = rcu::read_lock();
+ if self.is_available.load(Ordering::Relaxed) {
+ // SAFETY: Since `self.is_available` is true, data is initialised and has to remain
+ // valid because the RCU read side lock prevents it from being dropped.
+ Some(unsafe { RevocableGuard::new(self.data.assume_init_ref().get(), guard) })
+ } else {
+ None
+ }
+ }
+
+ /// Tries to access the \[revocable\] wrapped object.
+ ///
+ /// Returns `None` if the object has been revoked and is therefore no longer accessible.
+ ///
+ /// Returns a shared reference to the object otherwise; the object is guaranteed to
+ /// remain accessible while the rcu read side guard is alive. In such cases, callers are not
+ /// allowed to sleep because another CPU may be waiting to complete the revocation of this
+ /// object.
+ pub fn try_access_with_guard<'a>(&'a self, _guard: &'a rcu::Guard) -> Option<&'a T> {
+ if self.is_available.load(Ordering::Relaxed) {
+ // SAFETY: Since `self.is_available` is true, data is initialised and has to remain
+ // valid because the RCU read side lock prevents it from being dropped.
+ Some(unsafe { &*self.data.assume_init_ref().get() })
+ } else {
+ None
+ }
+ }
+
+ /// Revokes access to and drops the wrapped object.
+ ///
+ /// Access to the object is revoked immediately to new callers of [`Revocable::try_access`]. If
+ /// there are concurrent users of the object (i.e., ones that called [`Revocable::try_access`]
+ /// beforehand and still haven't dropped the returned guard), this function waits for the
+ /// concurrent access to complete before dropping the wrapped object.
+ pub fn revoke(&self) {
+ if self
+ .is_available
+ .compare_exchange(true, false, Ordering::Relaxed, Ordering::Relaxed)
+ .is_ok()
+ {
+ // SAFETY: Just an FFI call, there are no further requirements.
+ unsafe { bindings::synchronize_rcu() };
+
+ // SAFETY: We know `self.data` is valid because only one CPU can succeed the
+ // `compare_exchange` above that takes `is_available` from `true` to `false`.
+ unsafe { drop_in_place(self.data.assume_init_ref().get()) };
+ }
+ }
+}
+
+impl<T> Drop for Revocable<T> {
+ fn drop(&mut self) {
+ // Drop only if the data hasn't been revoked yet (in which case it has already been
+ // dropped).
+ if *self.is_available.get_mut() {
+ // SAFETY: We know `self.data` is valid because no other CPU has changed
+ // `is_available` to `false` yet, and no other CPU can do it anymore because this CPU
+ // holds the only reference (mutable) to `self` now.
+ unsafe { drop_in_place(self.data.assume_init_ref().get()) };
+ }
+ }
+}
+
+/// A guard that allows access to a revocable object and keeps it alive.
+///
+/// CPUs may not sleep while holding on to [`RevocableGuard`] because it's in atomic context
+/// holding the RCU read-side lock.
+///
+/// # Invariants
+///
+/// The RCU read-side lock is held while the guard is alive.
+pub struct RevocableGuard<'a, T> {
+ data_ref: *const T,
+ _rcu_guard: rcu::Guard,
+ _p: PhantomData<&'a ()>,
+}
+
+impl<T> RevocableGuard<'_, T> {
+ fn new(data_ref: *const T, rcu_guard: rcu::Guard) -> Self {
+ Self {
+ data_ref,
+ _rcu_guard: rcu_guard,
+ _p: PhantomData,
+ }
+ }
+}
+
+impl<T> Deref for RevocableGuard<'_, T> {
+ type Target = T;
+
+ fn deref(&self) -> &Self::Target {
+ // SAFETY: By the type invariants, we hold the rcu read-side lock, so the object is
+ // guaranteed to remain valid.
+ unsafe { &*self.data_ref }
+ }
+}
+
+/// An object that can become inaccessible at runtime.
+///
+/// Once access is revoked and all concurrent users complete (i.e., all existing instances of
+/// [`AsyncRevocableGuard`] are dropped), the wrapped object is also dropped.
+///
+/// Unlike [`Revocable`], [`AsyncRevocable`] does not wait for concurrent users of the wrapped
+/// object to finish before [`AsyncRevocable::revoke`] completes -- thus the async qualifier. This
+/// has the advantage of not requiring RCU locks or waits of any kind.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::revocable::AsyncRevocable;
+///
+/// struct Example {
+/// a: u32,
+/// b: u32,
+/// }
+///
+/// fn add_two(v: &AsyncRevocable<Example>) -> Option<u32> {
+/// let guard = v.try_access()?;
+/// Some(guard.a + guard.b)
+/// }
+///
+/// let v = AsyncRevocable::new(Example { a: 10, b: 20 });
+/// assert_eq!(add_two(&v), Some(30));
+/// v.revoke();
+/// assert_eq!(add_two(&v), None);
+/// ```
+///
+/// Example where revocation happens while there is a user:
+///
+/// ```
+/// # use kernel::revocable::AsyncRevocable;
+/// use core::sync::atomic::{AtomicBool, Ordering};
+///
+/// struct Example {
+/// a: u32,
+/// b: u32,
+/// }
+///
+/// static DROPPED: AtomicBool = AtomicBool::new(false);
+///
+/// impl Drop for Example {
+/// fn drop(&mut self) {
+/// DROPPED.store(true, Ordering::Relaxed);
+/// }
+/// }
+///
+/// fn add_two(v: &AsyncRevocable<Example>) -> Option<u32> {
+/// let guard = v.try_access()?;
+/// Some(guard.a + guard.b)
+/// }
+///
+/// let v = AsyncRevocable::new(Example { a: 10, b: 20 });
+/// assert_eq!(add_two(&v), Some(30));
+///
+/// let guard = v.try_access().unwrap();
+/// assert!(!v.is_revoked());
+/// assert!(!DROPPED.load(Ordering::Relaxed));
+/// v.revoke();
+/// assert!(!DROPPED.load(Ordering::Relaxed));
+/// assert!(v.is_revoked());
+/// assert!(v.try_access().is_none());
+/// assert_eq!(guard.a + guard.b, 30);
+/// drop(guard);
+/// assert!(DROPPED.load(Ordering::Relaxed));
+/// ```
+pub struct AsyncRevocable<T> {
+ usage_count: AtomicU32,
+ data: MaybeUninit<UnsafeCell<T>>,
+}
+
+// SAFETY: `AsyncRevocable` is `Send` if the wrapped object is also `Send`. This is because while
+// the functionality exposed by `AsyncRevocable` can be accessed from any thread/CPU, it is
+// possible that this isn't supported by the wrapped object.
+unsafe impl<T: Send> Send for AsyncRevocable<T> {}
+
+// SAFETY: `AsyncRevocable` is `Sync` if the wrapped object is both `Send` and `Sync`. We require
+// `Send` from the wrapped object as well because of `AsyncRevocable::revoke`, which can trigger
+// the `Drop` implementation of the wrapped object from an arbitrary thread.
+unsafe impl<T: Sync + Send> Sync for AsyncRevocable<T> {}
+
+const REVOKED: u32 = 0x80000000;
+const COUNT_MASK: u32 = !REVOKED;
+const SATURATED_COUNT: u32 = REVOKED - 1;
+
+impl<T> AsyncRevocable<T> {
+ /// Creates a new asynchronously revocable instance of the given data.
+ pub fn new(data: T) -> Self {
+ Self {
+ usage_count: AtomicU32::new(0),
+ data: MaybeUninit::new(UnsafeCell::new(data)),
+ }
+ }
+
+ /// Tries to access the \[revocable\] wrapped object.
+ ///
+ /// Returns `None` if the object has been revoked and is therefore no longer accessible.
+ ///
+ /// Returns a guard that gives access to the object otherwise; the object is guaranteed to
+ /// remain accessible while the guard is alive.
+ pub fn try_access(&self) -> Option<AsyncRevocableGuard<'_, T>> {
+ loop {
+ let count = self.usage_count.load(Ordering::Relaxed);
+
+ // Fail attempt to access if the object is already revoked.
+ if count & REVOKED != 0 {
+ return None;
+ }
+
+ // No need to increment if the count is saturated.
+ if count == SATURATED_COUNT
+ || self
+ .usage_count
+ .compare_exchange(count, count + 1, Ordering::Relaxed, Ordering::Relaxed)
+ .is_ok()
+ {
+ return Some(AsyncRevocableGuard { revocable: self });
+ }
+ }
+ }
+
+ /// Revokes access to the protected object.
+ ///
+ /// Returns `true` if access has been revoked, or `false` when the object has already been
+ /// revoked by a previous call to [`AsyncRevocable::revoke`].
+ ///
+ /// This call is non-blocking, that is, no new users of the revocable object will be allowed,
+ /// but potential current users are able to continue to use it and the thread won't wait for
+ /// them to finish. In such cases, the object will be dropped when the last user completes.
+ pub fn revoke(&self) -> bool {
+ // Set the `REVOKED` bit.
+ //
+ // The acquire barrier matches up with the release when decrementing the usage count.
+ let prev = self.usage_count.fetch_or(REVOKED, Ordering::Acquire);
+ if prev & REVOKED != 0 {
+ // Another thread already revoked this object.
+ return false;
+ }
+
+ if prev == 0 {
+ // SAFETY: This thread just revoked the object and the usage count is zero, so the
+ // object is valid and there will be no future users.
+ unsafe { drop_in_place(UnsafeCell::raw_get(self.data.as_ptr())) };
+ }
+
+ true
+ }
+
+ /// Returns whether access to the object has been revoked.
+ pub fn is_revoked(&self) -> bool {
+ self.usage_count.load(Ordering::Relaxed) & REVOKED != 0
+ }
+}
+
+impl<T> Drop for AsyncRevocable<T> {
+ fn drop(&mut self) {
+ let count = *self.usage_count.get_mut();
+ if count != REVOKED {
+ // The object hasn't been dropped yet, so we do it now.
+
+ // This matches with the release when decrementing the usage count.
+ fence(Ordering::Acquire);
+
+ // SAFETY: Since `count` is does not indicate a count of 0 and the REVOKED bit set, the
+ // object is still valid.
+ unsafe { drop_in_place(UnsafeCell::raw_get(self.data.as_ptr())) };
+ }
+ }
+}
+
+/// A guard that allows access to a revocable object and keeps it alive.
+///
+/// # Invariants
+///
+/// The owner owns an increment on the usage count (which may have saturated it), which keeps the
+/// revocable object alive.
+pub struct AsyncRevocableGuard<'a, T> {
+ revocable: &'a AsyncRevocable<T>,
+}
+
+impl<T> Deref for AsyncRevocableGuard<'_, T> {
+ type Target = T;
+
+ fn deref(&self) -> &Self::Target {
+ // SAFETY: The type invariants guarantee that the caller owns an increment.
+ unsafe { &*self.revocable.data.assume_init_ref().get() }
+ }
+}
+
+impl<T> Drop for AsyncRevocableGuard<'_, T> {
+ fn drop(&mut self) {
+ loop {
+ let count = self.revocable.usage_count.load(Ordering::Relaxed);
+ let actual_count = count & COUNT_MASK;
+ if actual_count == SATURATED_COUNT {
+ // The count is saturated, so we won't decrement (nor do we drop the object).
+ return;
+ }
+
+ if actual_count == 0 {
+ // Trying to underflow the count.
+ panic!("actual_count is zero");
+ }
+
+ // On success, we use release ordering, which matches with the acquire in one of the
+ // places where we drop the object, namely: below, in `AsyncRevocable::revoke`, or in
+ // `AsyncRevocable::drop`.
+ if self
+ .revocable
+ .usage_count
+ .compare_exchange(count, count - 1, Ordering::Release, Ordering::Relaxed)
+ .is_ok()
+ {
+ if count == 1 | REVOKED {
+ // `count` is now zero and it is revoked, so free it now.
+
+ // This matches with the release above (which may have happened in other
+ // threads concurrently).
+ fence(Ordering::Acquire);
+
+ // SAFETY: Since `count` was 1, the object is still alive.
+ unsafe { drop_in_place(UnsafeCell::raw_get(self.revocable.data.as_ptr())) };
+ }
+
+ return;
+ }
+ }
+ }
+}
diff --git a/rust/kernel/security.rs b/rust/kernel/security.rs
new file mode 100644
index 000000000000..0a33363289d3
--- /dev/null
+++ b/rust/kernel/security.rs
@@ -0,0 +1,38 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Linux Security Modules (LSM).
+//!
+//! C header: [`include/linux/security.h`](../../../../include/linux/security.h).
+
+use crate::{bindings, cred::Credential, file::File, to_result, Result};
+
+/// Calls the security modules to determine if the given task can become the manager of a binder
+/// context.
+pub fn binder_set_context_mgr(mgr: &Credential) -> Result {
+ // SAFETY: `mrg.0` is valid because the shared reference guarantees a nonzero refcount.
+ to_result(unsafe { bindings::security_binder_set_context_mgr(mgr.0.get()) })
+}
+
+/// Calls the security modules to determine if binder transactions are allowed from task `from` to
+/// task `to`.
+pub fn binder_transaction(from: &Credential, to: &Credential) -> Result {
+ // SAFETY: `from` and `to` are valid because the shared references guarantee nonzero refcounts.
+ to_result(unsafe { bindings::security_binder_transaction(from.0.get(), to.0.get()) })
+}
+
+/// Calls the security modules to determine if task `from` is allowed to send binder objects
+/// (owned by itself or other processes) to task `to` through a binder transaction.
+pub fn binder_transfer_binder(from: &Credential, to: &Credential) -> Result {
+ // SAFETY: `from` and `to` are valid because the shared references guarantee nonzero refcounts.
+ to_result(unsafe { bindings::security_binder_transfer_binder(from.0.get(), to.0.get()) })
+}
+
+/// Calls the security modules to determine if task `from` is allowed to send the given file to
+/// task `to` (which would get its own file descriptor) through a binder transaction.
+pub fn binder_transfer_file(from: &Credential, to: &Credential, file: &File) -> Result {
+ // SAFETY: `from`, `to` and `file` are valid because the shared references guarantee nonzero
+ // refcounts.
+ to_result(unsafe {
+ bindings::security_binder_transfer_file(from.0.get(), to.0.get(), file.0.get())
+ })
+}
diff --git a/rust/kernel/static_assert.rs b/rust/kernel/static_assert.rs
new file mode 100644
index 000000000000..3115ee0ba8e9
--- /dev/null
+++ b/rust/kernel/static_assert.rs
@@ -0,0 +1,34 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Static assert.
+
+/// Static assert (i.e. compile-time assert).
+///
+/// Similar to C11 [`_Static_assert`] and C++11 [`static_assert`].
+///
+/// The feature may be added to Rust in the future: see [RFC 2790].
+///
+/// [`_Static_assert`]: https://en.cppreference.com/w/c/language/_Static_assert
+/// [`static_assert`]: https://en.cppreference.com/w/cpp/language/static_assert
+/// [RFC 2790]: https://github.com/rust-lang/rfcs/issues/2790
+///
+/// # Examples
+///
+/// ```
+/// static_assert!(42 > 24);
+/// static_assert!(core::mem::size_of::<u8>() == 1);
+///
+/// const X: &[u8] = b"bar";
+/// static_assert!(X[1] == b'a');
+///
+/// const fn f(x: i32) -> i32 {
+/// x + 2
+/// }
+/// static_assert!(f(40) == 42);
+/// ```
+#[macro_export]
+macro_rules! static_assert {
+ ($condition:expr) => {
+ const _: () = core::assert!($condition);
+ };
+}
diff --git a/rust/kernel/std_vendor.rs b/rust/kernel/std_vendor.rs
new file mode 100644
index 000000000000..ffbaca0c4cb7
--- /dev/null
+++ b/rust/kernel/std_vendor.rs
@@ -0,0 +1,161 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
+//! The contents of this file come from the Rust standard library, hosted in
+//! the <https://github.com/rust-lang/rust> repository, licensed under
+//! "Apache-2.0 OR MIT" and adapted for kernel use. For copyright details,
+//! see <https://github.com/rust-lang/rust/blob/master/COPYRIGHT>.
+
+/// [`std::dbg`], but using [`pr_info`] instead of [`eprintln`].
+///
+/// Prints and returns the value of a given expression for quick and dirty
+/// debugging.
+///
+/// An example:
+///
+/// ```rust
+/// let a = 2;
+/// # #[allow(clippy::dbg_macro)]
+/// let b = dbg!(a * 2) + 1;
+/// // ^-- prints: [src/main.rs:2] a * 2 = 4
+/// assert_eq!(b, 5);
+/// ```
+///
+/// The macro works by using the `Debug` implementation of the type of
+/// the given expression to print the value with [`printk`] along with the
+/// source location of the macro invocation as well as the source code
+/// of the expression.
+///
+/// Invoking the macro on an expression moves and takes ownership of it
+/// before returning the evaluated expression unchanged. If the type
+/// of the expression does not implement `Copy` and you don't want
+/// to give up ownership, you can instead borrow with `dbg!(&expr)`
+/// for some expression `expr`.
+///
+/// The `dbg!` macro works exactly the same in release builds.
+/// This is useful when debugging issues that only occur in release
+/// builds or when debugging in release mode is significantly faster.
+///
+/// Note that the macro is intended as a debugging tool and therefore you
+/// should avoid having uses of it in version control for long periods
+/// (other than in tests and similar).
+///
+/// # Stability
+///
+/// The exact output printed by this macro should not be relied upon
+/// and is subject to future changes.
+///
+/// # Further examples
+///
+/// With a method call:
+///
+/// ```rust
+/// # #[allow(clippy::dbg_macro)]
+/// fn foo(n: usize) {
+/// if dbg!(n.checked_sub(4)).is_some() {
+/// // ...
+/// }
+/// }
+///
+/// foo(3)
+/// ```
+///
+/// This prints to the kernel log:
+///
+/// ```text,ignore
+/// [src/main.rs:4] n.checked_sub(4) = None
+/// ```
+///
+/// Naive factorial implementation:
+///
+/// ```rust
+/// # #[allow(clippy::dbg_macro)]
+/// # {
+/// fn factorial(n: u32) -> u32 {
+/// if dbg!(n <= 1) {
+/// dbg!(1)
+/// } else {
+/// dbg!(n * factorial(n - 1))
+/// }
+/// }
+///
+/// dbg!(factorial(4));
+/// # }
+/// ```
+///
+/// This prints to the kernel log:
+///
+/// ```text,ignore
+/// [src/main.rs:3] n <= 1 = false
+/// [src/main.rs:3] n <= 1 = false
+/// [src/main.rs:3] n <= 1 = false
+/// [src/main.rs:3] n <= 1 = true
+/// [src/main.rs:4] 1 = 1
+/// [src/main.rs:5] n * factorial(n - 1) = 2
+/// [src/main.rs:5] n * factorial(n - 1) = 6
+/// [src/main.rs:5] n * factorial(n - 1) = 24
+/// [src/main.rs:11] factorial(4) = 24
+/// ```
+///
+/// The `dbg!(..)` macro moves the input:
+///
+// TODO: Could be `compile_fail` when supported.
+/// ```ignore
+/// /// A wrapper around `usize` which importantly is not Copyable.
+/// #[derive(Debug)]
+/// struct NoCopy(usize);
+///
+/// let a = NoCopy(42);
+/// let _ = dbg!(a); // <-- `a` is moved here.
+/// let _ = dbg!(a); // <-- `a` is moved again; error!
+/// ```
+///
+/// You can also use `dbg!()` without a value to just print the
+/// file and line whenever it's reached.
+///
+/// Finally, if you want to `dbg!(..)` multiple values, it will treat them as
+/// a tuple (and return it, too):
+///
+/// ```
+/// # #[allow(clippy::dbg_macro)]
+/// assert_eq!(dbg!(1usize, 2u32), (1, 2));
+/// ```
+///
+/// However, a single argument with a trailing comma will still not be treated
+/// as a tuple, following the convention of ignoring trailing commas in macro
+/// invocations. You can use a 1-tuple directly if you need one:
+///
+/// ```
+/// # #[allow(clippy::dbg_macro)]
+/// # {
+/// assert_eq!(1, dbg!(1u32,)); // trailing comma ignored
+/// assert_eq!((1,), dbg!((1u32,))); // 1-tuple
+/// # }
+/// ```
+///
+/// [`std::dbg`]: https://doc.rust-lang.org/std/macro.dbg.html
+/// [`eprintln`]: https://doc.rust-lang.org/std/macro.eprintln.html
+/// [`printk`]: https://www.kernel.org/doc/html/latest/core-api/printk-basics.html
+#[macro_export]
+macro_rules! dbg {
+ // NOTE: We cannot use `concat!` to make a static string as a format argument
+ // of `pr_info!` because `file!` could contain a `{` or
+ // `$val` expression could be a block (`{ .. }`), in which case the `pr_info!`
+ // will be malformed.
+ () => {
+ $crate::pr_info!("[{}:{}]\n", ::core::file!(), ::core::line!())
+ };
+ ($val:expr $(,)?) => {
+ // Use of `match` here is intentional because it affects the lifetimes
+ // of temporaries - https://stackoverflow.com/a/48732525/1063961
+ match $val {
+ tmp => {
+ $crate::pr_info!("[{}:{}] {} = {:#?}\n",
+ ::core::file!(), ::core::line!(), ::core::stringify!($val), &tmp);
+ tmp
+ }
+ }
+ };
+ ($($val:expr),+ $(,)?) => {
+ ($($crate::dbg!($val)),+,)
+ };
+}
diff --git a/rust/kernel/str.rs b/rust/kernel/str.rs
new file mode 100644
index 000000000000..874003e39cba
--- /dev/null
+++ b/rust/kernel/str.rs
@@ -0,0 +1,597 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! String representations.
+
+use alloc::vec::Vec;
+use core::fmt::{self, Write};
+use core::ops::{self, Deref, Index};
+
+use crate::{bindings, error::code::*, Error};
+
+/// Byte string without UTF-8 validity guarantee.
+///
+/// `BStr` is simply an alias to `[u8]`, but has a more evident semantical meaning.
+pub type BStr = [u8];
+
+/// Creates a new [`BStr`] from a string literal.
+///
+/// `b_str!` converts the supplied string literal to byte string, so non-ASCII
+/// characters can be included.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::b_str;
+/// # use kernel::str::BStr;
+/// const MY_BSTR: &BStr = b_str!("My awesome BStr!");
+/// ```
+#[macro_export]
+macro_rules! b_str {
+ ($str:literal) => {{
+ const S: &'static str = $str;
+ const C: &'static $crate::str::BStr = S.as_bytes();
+ C
+ }};
+}
+
+/// Possible errors when using conversion functions in [`CStr`].
+#[derive(Debug, Clone, Copy)]
+pub enum CStrConvertError {
+ /// Supplied bytes contain an interior `NUL`.
+ InteriorNul,
+
+ /// Supplied bytes are not terminated by `NUL`.
+ NotNulTerminated,
+}
+
+impl From<CStrConvertError> for Error {
+ #[inline]
+ fn from(_: CStrConvertError) -> Error {
+ EINVAL
+ }
+}
+
+/// A string that is guaranteed to have exactly one `NUL` byte, which is at the
+/// end.
+///
+/// Used for interoperability with kernel APIs that take C strings.
+#[repr(transparent)]
+pub struct CStr([u8]);
+
+impl CStr {
+ /// Returns the length of this string excluding `NUL`.
+ #[inline]
+ pub const fn len(&self) -> usize {
+ self.len_with_nul() - 1
+ }
+
+ /// Returns the length of this string with `NUL`.
+ #[inline]
+ pub const fn len_with_nul(&self) -> usize {
+ // SAFETY: This is one of the invariant of `CStr`.
+ // We add a `unreachable_unchecked` here to hint the optimizer that
+ // the value returned from this function is non-zero.
+ if self.0.is_empty() {
+ unsafe { core::hint::unreachable_unchecked() };
+ }
+ self.0.len()
+ }
+
+ /// Returns `true` if the string only includes `NUL`.
+ #[inline]
+ pub const fn is_empty(&self) -> bool {
+ self.len() == 0
+ }
+
+ /// Wraps a raw C string pointer.
+ ///
+ /// # Safety
+ ///
+ /// `ptr` must be a valid pointer to a `NUL`-terminated C string, and it must
+ /// last at least `'a`. When `CStr` is alive, the memory pointed by `ptr`
+ /// must not be mutated.
+ #[inline]
+ pub unsafe fn from_char_ptr<'a>(ptr: *const core::ffi::c_char) -> &'a Self {
+ // SAFETY: The safety precondition guarantees `ptr` is a valid pointer
+ // to a `NUL`-terminated C string.
+ let len = unsafe { bindings::strlen(ptr) } + 1;
+ // SAFETY: Lifetime guaranteed by the safety precondition.
+ let bytes = unsafe { core::slice::from_raw_parts(ptr as _, len as _) };
+ // SAFETY: As `len` is returned by `strlen`, `bytes` does not contain interior `NUL`.
+ // As we have added 1 to `len`, the last byte is known to be `NUL`.
+ unsafe { Self::from_bytes_with_nul_unchecked(bytes) }
+ }
+
+ /// Creates a [`CStr`] from a `[u8]`.
+ ///
+ /// The provided slice must be `NUL`-terminated, does not contain any
+ /// interior `NUL` bytes.
+ pub const fn from_bytes_with_nul(bytes: &[u8]) -> Result<&Self, CStrConvertError> {
+ if bytes.is_empty() {
+ return Err(CStrConvertError::NotNulTerminated);
+ }
+ if bytes[bytes.len() - 1] != 0 {
+ return Err(CStrConvertError::NotNulTerminated);
+ }
+ let mut i = 0;
+ // `i + 1 < bytes.len()` allows LLVM to optimize away bounds checking,
+ // while it couldn't optimize away bounds checks for `i < bytes.len() - 1`.
+ while i + 1 < bytes.len() {
+ if bytes[i] == 0 {
+ return Err(CStrConvertError::InteriorNul);
+ }
+ i += 1;
+ }
+ // SAFETY: We just checked that all properties hold.
+ Ok(unsafe { Self::from_bytes_with_nul_unchecked(bytes) })
+ }
+
+ /// Creates a [`CStr`] from a `[u8]`, panic if input is not valid.
+ ///
+ /// This function is only meant to be used by `c_str!` macro, so
+ /// crates using `c_str!` macro don't have to enable `const_panic` feature.
+ #[doc(hidden)]
+ pub const fn from_bytes_with_nul_unwrap(bytes: &[u8]) -> &Self {
+ match Self::from_bytes_with_nul(bytes) {
+ Ok(v) => v,
+ Err(_) => panic!("string contains interior NUL"),
+ }
+ }
+
+ /// Creates a [`CStr`] from a `[u8]` without performing any additional
+ /// checks.
+ ///
+ /// # Safety
+ ///
+ /// `bytes` *must* end with a `NUL` byte, and should only have a single
+ /// `NUL` byte (or the string will be truncated).
+ #[inline]
+ pub const unsafe fn from_bytes_with_nul_unchecked(bytes: &[u8]) -> &CStr {
+ // SAFETY: Properties of `bytes` guaranteed by the safety precondition.
+ unsafe { core::mem::transmute(bytes) }
+ }
+
+ /// Returns a C pointer to the string.
+ #[inline]
+ pub const fn as_char_ptr(&self) -> *const core::ffi::c_char {
+ self.0.as_ptr() as _
+ }
+
+ /// Convert the string to a byte slice without the trailing 0 byte.
+ #[inline]
+ pub fn as_bytes(&self) -> &[u8] {
+ &self.0[..self.len()]
+ }
+
+ /// Convert the string to a byte slice containing the trailing 0 byte.
+ #[inline]
+ pub const fn as_bytes_with_nul(&self) -> &[u8] {
+ &self.0
+ }
+
+ /// Yields a [`&str`] slice if the [`CStr`] contains valid UTF-8.
+ ///
+ /// If the contents of the [`CStr`] are valid UTF-8 data, this
+ /// function will return the corresponding [`&str`] slice. Otherwise,
+ /// it will return an error with details of where UTF-8 validation failed.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// # use kernel::str::CStr;
+ /// let cstr = CStr::from_bytes_with_nul(b"foo\0").unwrap();
+ /// assert_eq!(cstr.to_str(), Ok("foo"));
+ /// ```
+ #[inline]
+ pub fn to_str(&self) -> Result<&str, core::str::Utf8Error> {
+ core::str::from_utf8(self.as_bytes())
+ }
+
+ /// Unsafely convert this [`CStr`] into a [`&str`], without checking for
+ /// valid UTF-8.
+ ///
+ /// # Safety
+ ///
+ /// The contents must be valid UTF-8.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// # use kernel::c_str;
+ /// # use kernel::str::CStr;
+ /// // SAFETY: String literals are guaranteed to be valid UTF-8
+ /// // by the Rust compiler.
+ /// let bar = c_str!("ツ");
+ /// assert_eq!(unsafe { bar.as_str_unchecked() }, "ツ");
+ /// ```
+ #[inline]
+ pub unsafe fn as_str_unchecked(&self) -> &str {
+ unsafe { core::str::from_utf8_unchecked(self.as_bytes()) }
+ }
+}
+
+impl fmt::Display for CStr {
+ /// Formats printable ASCII characters, escaping the rest.
+ ///
+ /// ```
+ /// # use kernel::c_str;
+ /// # use kernel::str::CStr;
+ /// # use kernel::str::CString;
+ /// let penguin = c_str!("🐧");
+ /// let s = CString::try_from_fmt(fmt!("{}", penguin)).unwrap();
+ /// assert_eq!(s.as_bytes_with_nul(), "\\xf0\\x9f\\x90\\xa7\0".as_bytes());
+ ///
+ /// let ascii = c_str!("so \"cool\"");
+ /// let s = CString::try_from_fmt(fmt!("{}", ascii)).unwrap();
+ /// assert_eq!(s.as_bytes_with_nul(), "so \"cool\"\0".as_bytes());
+ /// ```
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ for &c in self.as_bytes() {
+ if (0x20..0x7f).contains(&c) {
+ // Printable character.
+ f.write_char(c as char)?;
+ } else {
+ write!(f, "\\x{:02x}", c)?;
+ }
+ }
+ Ok(())
+ }
+}
+
+impl fmt::Debug for CStr {
+ /// Formats printable ASCII characters with a double quote on either end, escaping the rest.
+ ///
+ /// ```
+ /// # use kernel::c_str;
+ /// # use kernel::str::CStr;
+ /// # use kernel::str::CString;
+ /// let penguin = c_str!("🐧");
+ /// let s = CString::try_from_fmt(fmt!("{:?}", penguin)).unwrap();
+ /// assert_eq!(s.as_bytes_with_nul(), "\"\\xf0\\x9f\\x90\\xa7\"\0".as_bytes());
+ ///
+ /// // Embedded double quotes are escaped.
+ /// let ascii = c_str!("so \"cool\"");
+ /// let s = CString::try_from_fmt(fmt!("{:?}", ascii)).unwrap();
+ /// assert_eq!(s.as_bytes_with_nul(), "\"so \\\"cool\\\"\"\0".as_bytes());
+ /// ```
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ f.write_str("\"")?;
+ for &c in self.as_bytes() {
+ match c {
+ // Printable characters.
+ b'\"' => f.write_str("\\\"")?,
+ 0x20..=0x7e => f.write_char(c as char)?,
+ _ => write!(f, "\\x{:02x}", c)?,
+ }
+ }
+ f.write_str("\"")
+ }
+}
+
+impl AsRef<BStr> for CStr {
+ #[inline]
+ fn as_ref(&self) -> &BStr {
+ self.as_bytes()
+ }
+}
+
+impl Deref for CStr {
+ type Target = BStr;
+
+ #[inline]
+ fn deref(&self) -> &Self::Target {
+ self.as_bytes()
+ }
+}
+
+impl Index<ops::RangeFrom<usize>> for CStr {
+ type Output = CStr;
+
+ #[inline]
+ fn index(&self, index: ops::RangeFrom<usize>) -> &Self::Output {
+ // Delegate bounds checking to slice.
+ // Assign to _ to mute clippy's unnecessary operation warning.
+ let _ = &self.as_bytes()[index.start..];
+ // SAFETY: We just checked the bounds.
+ unsafe { Self::from_bytes_with_nul_unchecked(&self.0[index.start..]) }
+ }
+}
+
+impl Index<ops::RangeFull> for CStr {
+ type Output = CStr;
+
+ #[inline]
+ fn index(&self, _index: ops::RangeFull) -> &Self::Output {
+ self
+ }
+}
+
+mod private {
+ use core::ops;
+
+ // Marker trait for index types that can be forward to `BStr`.
+ pub trait CStrIndex {}
+
+ impl CStrIndex for usize {}
+ impl CStrIndex for ops::Range<usize> {}
+ impl CStrIndex for ops::RangeInclusive<usize> {}
+ impl CStrIndex for ops::RangeToInclusive<usize> {}
+}
+
+impl<Idx> Index<Idx> for CStr
+where
+ Idx: private::CStrIndex,
+ BStr: Index<Idx>,
+{
+ type Output = <BStr as Index<Idx>>::Output;
+
+ #[inline]
+ fn index(&self, index: Idx) -> &Self::Output {
+ &self.as_bytes()[index]
+ }
+}
+
+/// Creates a new [`CStr`] from a string literal.
+///
+/// The string literal should not contain any `NUL` bytes.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::c_str;
+/// # use kernel::str::CStr;
+/// const MY_CSTR: &CStr = c_str!("My awesome CStr!");
+/// ```
+#[macro_export]
+macro_rules! c_str {
+ ($str:expr) => {{
+ const S: &str = concat!($str, "\0");
+ const C: &$crate::str::CStr = $crate::str::CStr::from_bytes_with_nul_unwrap(S.as_bytes());
+ C
+ }};
+}
+
+#[cfg(test)]
+mod tests {
+ use super::*;
+
+ #[test]
+ fn test_cstr_to_str() {
+ let good_bytes = b"\xf0\x9f\xa6\x80\0";
+ let checked_cstr = CStr::from_bytes_with_nul(good_bytes).unwrap();
+ let checked_str = checked_cstr.to_str().unwrap();
+ assert_eq!(checked_str, "🦀");
+ }
+
+ #[test]
+ #[should_panic]
+ fn test_cstr_to_str_panic() {
+ let bad_bytes = b"\xc3\x28\0";
+ let checked_cstr = CStr::from_bytes_with_nul(bad_bytes).unwrap();
+ checked_cstr.to_str().unwrap();
+ }
+
+ #[test]
+ fn test_cstr_as_str_unchecked() {
+ let good_bytes = b"\xf0\x9f\x90\xA7\0";
+ let checked_cstr = CStr::from_bytes_with_nul(good_bytes).unwrap();
+ let unchecked_str = unsafe { checked_cstr.as_str_unchecked() };
+ assert_eq!(unchecked_str, "🐧");
+ }
+}
+
+/// Allows formatting of [`fmt::Arguments`] into a raw buffer.
+///
+/// It does not fail if callers write past the end of the buffer so that they can calculate the
+/// size required to fit everything.
+///
+/// # Invariants
+///
+/// The memory region between `pos` (inclusive) and `end` (exclusive) is valid for writes if `pos`
+/// is less than `end`.
+pub(crate) struct RawFormatter {
+ // Use `usize` to use `saturating_*` functions.
+ beg: usize,
+ pos: usize,
+ end: usize,
+}
+
+impl RawFormatter {
+ /// Creates a new instance of [`RawFormatter`] with an empty buffer.
+ fn new() -> Self {
+ // INVARIANT: The buffer is empty, so the region that needs to be writable is empty.
+ Self {
+ beg: 0,
+ pos: 0,
+ end: 0,
+ }
+ }
+
+ /// Creates a new instance of [`RawFormatter`] with the given buffer pointers.
+ ///
+ /// # Safety
+ ///
+ /// If `pos` is less than `end`, then the region between `pos` (inclusive) and `end`
+ /// (exclusive) must be valid for writes for the lifetime of the returned [`RawFormatter`].
+ pub(crate) unsafe fn from_ptrs(pos: *mut u8, end: *mut u8) -> Self {
+ // INVARIANT: The safety requierments guarantee the type invariants.
+ Self {
+ beg: pos as _,
+ pos: pos as _,
+ end: end as _,
+ }
+ }
+
+ /// Creates a new instance of [`RawFormatter`] with the given buffer.
+ ///
+ /// # Safety
+ ///
+ /// The memory region starting at `buf` and extending for `len` bytes must be valid for writes
+ /// for the lifetime of the returned [`RawFormatter`].
+ pub(crate) unsafe fn from_buffer(buf: *mut u8, len: usize) -> Self {
+ let pos = buf as usize;
+ // INVARIANT: We ensure that `end` is never less then `buf`, and the safety requirements
+ // guarantees that the memory region is valid for writes.
+ Self {
+ pos,
+ beg: pos,
+ end: pos.saturating_add(len),
+ }
+ }
+
+ /// Returns the current insert position.
+ ///
+ /// N.B. It may point to invalid memory.
+ pub(crate) fn pos(&self) -> *mut u8 {
+ self.pos as _
+ }
+
+ /// Return the number of bytes written to the formatter.
+ pub(crate) fn bytes_written(&self) -> usize {
+ self.pos - self.beg
+ }
+}
+
+impl fmt::Write for RawFormatter {
+ fn write_str(&mut self, s: &str) -> fmt::Result {
+ // `pos` value after writing `len` bytes. This does not have to be bounded by `end`, but we
+ // don't want it to wrap around to 0.
+ let pos_new = self.pos.saturating_add(s.len());
+
+ // Amount that we can copy. `saturating_sub` ensures we get 0 if `pos` goes past `end`.
+ let len_to_copy = core::cmp::min(pos_new, self.end).saturating_sub(self.pos);
+
+ if len_to_copy > 0 {
+ // SAFETY: If `len_to_copy` is non-zero, then we know `pos` has not gone past `end`
+ // yet, so it is valid for write per the type invariants.
+ unsafe {
+ core::ptr::copy_nonoverlapping(
+ s.as_bytes().as_ptr(),
+ self.pos as *mut u8,
+ len_to_copy,
+ )
+ };
+ }
+
+ self.pos = pos_new;
+ Ok(())
+ }
+}
+
+/// Allows formatting of [`fmt::Arguments`] into a raw buffer.
+///
+/// Fails if callers attempt to write more than will fit in the buffer.
+pub(crate) struct Formatter(RawFormatter);
+
+impl Formatter {
+ /// Creates a new instance of [`Formatter`] with the given buffer.
+ ///
+ /// # Safety
+ ///
+ /// The memory region starting at `buf` and extending for `len` bytes must be valid for writes
+ /// for the lifetime of the returned [`Formatter`].
+ pub(crate) unsafe fn from_buffer(buf: *mut u8, len: usize) -> Self {
+ // SAFETY: The safety requirements of this function satisfy those of the callee.
+ Self(unsafe { RawFormatter::from_buffer(buf, len) })
+ }
+}
+
+impl Deref for Formatter {
+ type Target = RawFormatter;
+
+ fn deref(&self) -> &Self::Target {
+ &self.0
+ }
+}
+
+impl fmt::Write for Formatter {
+ fn write_str(&mut self, s: &str) -> fmt::Result {
+ self.0.write_str(s)?;
+
+ // Fail the request if we go past the end of the buffer.
+ if self.0.pos > self.0.end {
+ Err(fmt::Error)
+ } else {
+ Ok(())
+ }
+ }
+}
+
+/// An owned string that is guaranteed to have exactly one `NUL` byte, which is at the end.
+///
+/// Used for interoperability with kernel APIs that take C strings.
+///
+/// # Invariants
+///
+/// The string is always `NUL`-terminated and contains no other `NUL` bytes.
+///
+/// # Examples
+///
+/// ```
+/// use kernel::str::CString;
+///
+/// let s = CString::try_from_fmt(fmt!("{}{}{}", "abc", 10, 20)).unwrap();
+/// assert_eq!(s.as_bytes_with_nul(), "abc1020\0".as_bytes());
+///
+/// let tmp = "testing";
+/// let s = CString::try_from_fmt(fmt!("{tmp}{}", 123)).unwrap();
+/// assert_eq!(s.as_bytes_with_nul(), "testing123\0".as_bytes());
+///
+/// // This fails because it has an embedded `NUL` byte.
+/// let s = CString::try_from_fmt(fmt!("a\0b{}", 123));
+/// assert_eq!(s.is_ok(), false);
+/// ```
+pub struct CString {
+ buf: Vec<u8>,
+}
+
+impl CString {
+ /// Creates an instance of [`CString`] from the given formatted arguments.
+ pub fn try_from_fmt(args: fmt::Arguments<'_>) -> Result<Self, Error> {
+ // Calculate the size needed (formatted string plus `NUL` terminator).
+ let mut f = RawFormatter::new();
+ f.write_fmt(args)?;
+ f.write_str("\0")?;
+ let size = f.bytes_written();
+
+ // Allocate a vector with the required number of bytes, and write to it.
+ let mut buf = Vec::try_with_capacity(size)?;
+ // SAFETY: The buffer stored in `buf` is at least of size `size` and is valid for writes.
+ let mut f = unsafe { Formatter::from_buffer(buf.as_mut_ptr(), size) };
+ f.write_fmt(args)?;
+ f.write_str("\0")?;
+
+ // SAFETY: The number of bytes that can be written to `f` is bounded by `size`, which is
+ // `buf`'s capacity. The contents of the buffer have been initialised by writes to `f`.
+ unsafe { buf.set_len(f.bytes_written()) };
+
+ // Check that there are no `NUL` bytes before the end.
+ // SAFETY: The buffer is valid for read because `f.bytes_written()` is bounded by `size`
+ // (which the minimum buffer size) and is non-zero (we wrote at least the `NUL` terminator)
+ // so `f.bytes_written() - 1` doesn't underflow.
+ let ptr = unsafe { bindings::memchr(buf.as_ptr().cast(), 0, (f.bytes_written() - 1) as _) };
+ if !ptr.is_null() {
+ return Err(EINVAL);
+ }
+
+ // INVARIANT: We wrote the `NUL` terminator and checked above that no other `NUL` bytes
+ // exist in the buffer.
+ Ok(Self { buf })
+ }
+}
+
+impl Deref for CString {
+ type Target = CStr;
+
+ fn deref(&self) -> &Self::Target {
+ // SAFETY: The type invariants guarantee that the string is `NUL`-terminated and that no
+ // other `NUL` bytes exist.
+ unsafe { CStr::from_bytes_with_nul_unchecked(self.buf.as_slice()) }
+ }
+}
+
+/// A convenience alias for [`core::format_args`].
+#[macro_export]
+macro_rules! fmt {
+ ($($f:tt)*) => ( core::format_args!($($f)*) )
+}
diff --git a/rust/kernel/sync.rs b/rust/kernel/sync.rs
index dbf705d573e6..255a4928a47a 100644
--- a/rust/kernel/sync.rs
+++ b/rust/kernel/sync.rs
@@ -22,7 +22,7 @@
//! ```

use crate::{bindings, str::CStr};
-use core::pin::Pin;
+use core::{cell::UnsafeCell, mem::MaybeUninit, pin::Pin};

mod arc;
mod condvar;
@@ -30,13 +30,14 @@ mod guard;
mod locked_by;
mod mutex;
mod nowait;
+pub mod rcu;
mod revocable;
mod rwsem;
mod seqlock;
pub mod smutex;
mod spinlock;

-pub use arc::{Ref, RefBorrow, UniqueRef};
+pub use arc::{new_refcount, Ref, RefBorrow, StaticRef, UniqueRef};
pub use condvar::CondVar;
pub use guard::{Guard, Lock, LockFactory, LockInfo, LockIniter, ReadLock, WriteLock};
pub use locked_by::LockedBy;
@@ -47,6 +48,25 @@ pub use rwsem::{RevocableRwSemaphore, RevocableRwSemaphoreGuard, RwSemaphore};
pub use seqlock::{SeqLock, SeqLockReadGuard};
pub use spinlock::{RawSpinLock, SpinLock};

+/// Represents a lockdep class. It's a wrapper around C's `lock_class_key`.
+#[repr(transparent)]
+pub struct LockClassKey(UnsafeCell<MaybeUninit<bindings::lock_class_key>>);
+
+// SAFETY: This is a wrapper around a lock class key, so it is safe to use references to it from
+// any thread.
+unsafe impl Sync for LockClassKey {}
+
+impl LockClassKey {
+ /// Creates a new lock class key.
+ pub const fn new() -> Self {
+ Self(UnsafeCell::new(MaybeUninit::uninit()))
+ }
+
+ pub(crate) fn get(&self) -> *mut bindings::lock_class_key {
+ self.0.get().cast()
+ }
+}
+
/// Safely initialises an object that has an `init` function that takes a name and a lock class as
/// arguments, examples of these are [`Mutex`] and [`SpinLock`]. Each of them also provides a more
/// specialised name that uses this macro.
@@ -54,18 +74,11 @@ pub use spinlock::{RawSpinLock, SpinLock};
#[macro_export]
macro_rules! init_with_lockdep {
($obj:expr, $name:expr) => {{
- static mut CLASS1: core::mem::MaybeUninit<$crate::bindings::lock_class_key> =
- core::mem::MaybeUninit::uninit();
- static mut CLASS2: core::mem::MaybeUninit<$crate::bindings::lock_class_key> =
- core::mem::MaybeUninit::uninit();
+ static CLASS1: $crate::sync::LockClassKey = $crate::sync::LockClassKey::new();
+ static CLASS2: $crate::sync::LockClassKey = $crate::sync::LockClassKey::new();
let obj = $obj;
let name = $crate::c_str!($name);
- // SAFETY: `CLASS1` and `CLASS2` are never used by Rust code directly; the C portion of the
- // kernel may change it though.
- #[allow(unused_unsafe)]
- unsafe {
- $crate::sync::NeedsLockClass::init(obj, name, CLASS1.as_mut_ptr(), CLASS2.as_mut_ptr())
- };
+ $crate::sync::NeedsLockClass::init(obj, name, &CLASS1, &CLASS2)
}};
}

@@ -78,16 +91,11 @@ pub trait NeedsLockClass {
///
/// Callers are encouraged to use the [`init_with_lockdep`] macro as it automatically creates a
/// new lock class on each usage.
- ///
- /// # Safety
- ///
- /// `key1` and `key2` must point to valid memory locations and remain valid until `self` is
- /// dropped.
- unsafe fn init(
+ fn init(
self: Pin<&mut Self>,
name: &'static CStr,
- key1: *mut bindings::lock_class_key,
- key2: *mut bindings::lock_class_key,
+ key1: &'static LockClassKey,
+ key2: &'static LockClassKey,
);
}

diff --git a/rust/kernel/sysctl.rs b/rust/kernel/sysctl.rs
new file mode 100644
index 000000000000..8f742d60037d
--- /dev/null
+++ b/rust/kernel/sysctl.rs
@@ -0,0 +1,199 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! System control.
+//!
+//! C header: [`include/linux/sysctl.h`](../../../../include/linux/sysctl.h)
+//!
+//! Reference: <https://www.kernel.org/doc/Documentation/sysctl/README>
+
+use alloc::boxed::Box;
+use alloc::vec::Vec;
+use core::mem;
+use core::ptr;
+use core::sync::atomic;
+
+use crate::{
+ bindings,
+ error::code::*,
+ io_buffer::IoBufferWriter,
+ str::CStr,
+ types,
+ user_ptr::{UserSlicePtr, UserSlicePtrWriter},
+ Result,
+};
+
+/// Sysctl storage.
+pub trait SysctlStorage: Sync {
+ /// Writes a byte slice.
+ fn store_value(&self, data: &[u8]) -> (usize, Result);
+
+ /// Reads via a [`UserSlicePtrWriter`].
+ fn read_value(&self, data: &mut UserSlicePtrWriter) -> (usize, Result);
+}
+
+fn trim_whitespace(mut data: &[u8]) -> &[u8] {
+ while !data.is_empty() && (data[0] == b' ' || data[0] == b'\t' || data[0] == b'\n') {
+ data = &data[1..];
+ }
+ while !data.is_empty()
+ && (data[data.len() - 1] == b' '
+ || data[data.len() - 1] == b'\t'
+ || data[data.len() - 1] == b'\n')
+ {
+ data = &data[..data.len() - 1];
+ }
+ data
+}
+
+impl<T> SysctlStorage for &T
+where
+ T: SysctlStorage,
+{
+ fn store_value(&self, data: &[u8]) -> (usize, Result) {
+ (*self).store_value(data)
+ }
+
+ fn read_value(&self, data: &mut UserSlicePtrWriter) -> (usize, Result) {
+ (*self).read_value(data)
+ }
+}
+
+impl SysctlStorage for atomic::AtomicBool {
+ fn store_value(&self, data: &[u8]) -> (usize, Result) {
+ let result = match trim_whitespace(data) {
+ b"0" => {
+ self.store(false, atomic::Ordering::Relaxed);
+ Ok(())
+ }
+ b"1" => {
+ self.store(true, atomic::Ordering::Relaxed);
+ Ok(())
+ }
+ _ => Err(EINVAL),
+ };
+ (data.len(), result)
+ }
+
+ fn read_value(&self, data: &mut UserSlicePtrWriter) -> (usize, Result) {
+ let value = if self.load(atomic::Ordering::Relaxed) {
+ b"1\n"
+ } else {
+ b"0\n"
+ };
+ (value.len(), data.write_slice(value))
+ }
+}
+
+/// Holds a single `sysctl` entry (and its table).
+pub struct Sysctl<T: SysctlStorage> {
+ inner: Box<T>,
+ // Responsible for keeping the `ctl_table` alive.
+ _table: Box<[bindings::ctl_table]>,
+ header: *mut bindings::ctl_table_header,
+}
+
+// SAFETY: The only public method we have is `get()`, which returns `&T`, and
+// `T: Sync`. Any new methods must adhere to this requirement.
+unsafe impl<T: SysctlStorage> Sync for Sysctl<T> {}
+
+unsafe extern "C" fn proc_handler<T: SysctlStorage>(
+ ctl: *mut bindings::ctl_table,
+ write: core::ffi::c_int,
+ buffer: *mut core::ffi::c_void,
+ len: *mut usize,
+ ppos: *mut bindings::loff_t,
+) -> core::ffi::c_int {
+ // If we are reading from some offset other than the beginning of the file,
+ // return an empty read to signal EOF.
+ if unsafe { *ppos } != 0 && write == 0 {
+ unsafe { *len = 0 };
+ return 0;
+ }
+
+ let data = unsafe { UserSlicePtr::new(buffer, *len) };
+ let storage = unsafe { &*((*ctl).data as *const T) };
+ let (bytes_processed, result) = if write != 0 {
+ let data = match data.read_all() {
+ Ok(r) => r,
+ Err(e) => return e.to_kernel_errno(),
+ };
+ storage.store_value(&data)
+ } else {
+ let mut writer = data.writer();
+ storage.read_value(&mut writer)
+ };
+ unsafe { *len = bytes_processed };
+ unsafe { *ppos += *len as bindings::loff_t };
+ match result {
+ Ok(()) => 0,
+ Err(e) => e.to_kernel_errno(),
+ }
+}
+
+impl<T: SysctlStorage> Sysctl<T> {
+ /// Registers a single entry in `sysctl`.
+ pub fn register(
+ path: &'static CStr,
+ name: &'static CStr,
+ storage: T,
+ mode: types::Mode,
+ ) -> Result<Sysctl<T>> {
+ if name.contains(&b'/') {
+ return Err(EINVAL);
+ }
+
+ let storage = Box::try_new(storage)?;
+ let mut table = Vec::try_with_capacity(2)?;
+ table.try_push(bindings::ctl_table {
+ procname: name.as_char_ptr(),
+ mode: mode.as_int(),
+ data: &*storage as *const T as *mut core::ffi::c_void,
+ proc_handler: Some(proc_handler::<T>),
+
+ maxlen: 0,
+ child: ptr::null_mut(),
+ poll: ptr::null_mut(),
+ extra1: ptr::null_mut(),
+ extra2: ptr::null_mut(),
+ })?;
+ table.try_push(unsafe { mem::zeroed() })?;
+ let mut table = table.try_into_boxed_slice()?;
+
+ let result = unsafe { bindings::register_sysctl(path.as_char_ptr(), table.as_mut_ptr()) };
+ if result.is_null() {
+ return Err(ENOMEM);
+ }
+
+ Ok(Sysctl {
+ inner: storage,
+ _table: table,
+ header: result,
+ })
+ }
+
+ /// Gets the storage.
+ pub fn get(&self) -> &T {
+ &self.inner
+ }
+}
+
+impl<T: SysctlStorage> Drop for Sysctl<T> {
+ fn drop(&mut self) {
+ unsafe {
+ bindings::unregister_sysctl_table(self.header);
+ }
+ self.header = ptr::null_mut();
+ }
+}
+
+#[cfg(test)]
+mod tests {
+ use super::*;
+
+ #[test]
+ fn test_trim_whitespace() {
+ assert_eq!(trim_whitespace(b"foo "), b"foo");
+ assert_eq!(trim_whitespace(b" foo"), b"foo");
+ assert_eq!(trim_whitespace(b" foo "), b"foo");
+ }
+}
diff --git a/rust/kernel/task.rs b/rust/kernel/task.rs
new file mode 100644
index 000000000000..67040b532816
--- /dev/null
+++ b/rust/kernel/task.rs
@@ -0,0 +1,239 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Tasks (threads and processes).
+//!
+//! C header: [`include/linux/sched.h`](../../../../include/linux/sched.h).
+
+use crate::{
+ bindings, c_str, error::from_kernel_err_ptr, types::PointerWrapper, ARef, AlwaysRefCounted,
+ Result, ScopeGuard,
+};
+use alloc::boxed::Box;
+use core::{cell::UnsafeCell, fmt, marker::PhantomData, ops::Deref, ptr};
+
+/// Wraps the kernel's `struct task_struct`.
+///
+/// # Invariants
+///
+/// Instances of this type are always ref-counted, that is, a call to `get_task_struct` ensures
+/// that the allocation remains valid at least until the matching call to `put_task_struct`.
+///
+/// # Examples
+///
+/// The following is an example of getting the PID of the current thread with zero additional cost
+/// when compared to the C version:
+///
+/// ```
+/// use kernel::task::Task;
+///
+/// let pid = Task::current().pid();
+/// ```
+///
+/// Getting the PID of the current process, also zero additional cost:
+///
+/// ```
+/// use kernel::task::Task;
+///
+/// let pid = Task::current().group_leader().pid();
+/// ```
+///
+/// Getting the current task and storing it in some struct. The reference count is automatically
+/// incremented when creating `State` and decremented when it is dropped:
+///
+/// ```
+/// use kernel::{task::Task, ARef};
+///
+/// struct State {
+/// creator: ARef<Task>,
+/// index: u32,
+/// }
+///
+/// impl State {
+/// fn new() -> Self {
+/// Self {
+/// creator: Task::current().into(),
+/// index: 0,
+/// }
+/// }
+/// }
+/// ```
+#[repr(transparent)]
+pub struct Task(pub(crate) UnsafeCell<bindings::task_struct>);
+
+// SAFETY: It's OK to access `Task` through references from other threads because we're either
+// accessing properties that don't change (e.g., `pid`, `group_leader`) or that are properly
+// synchronised by C code (e.g., `signal_pending`).
+unsafe impl Sync for Task {}
+
+/// The type of process identifiers (PIDs).
+type Pid = bindings::pid_t;
+
+impl Task {
+ /// Returns a task reference for the currently executing task/thread.
+ pub fn current<'a>() -> TaskRef<'a> {
+ // SAFETY: Just an FFI call.
+ let ptr = unsafe { bindings::get_current() };
+
+ TaskRef {
+ // SAFETY: If the current thread is still running, the current task is valid. Given
+ // that `TaskRef` is not `Send`, we know it cannot be transferred to another thread
+ // (where it could potentially outlive the caller).
+ task: unsafe { &*ptr.cast() },
+ _not_send: PhantomData,
+ }
+ }
+
+ /// Returns the group leader of the given task.
+ pub fn group_leader(&self) -> &Task {
+ // SAFETY: By the type invariant, we know that `self.0` is valid.
+ let ptr = unsafe { core::ptr::addr_of!((*self.0.get()).group_leader).read() };
+
+ // SAFETY: The lifetime of the returned task reference is tied to the lifetime of `self`,
+ // and given that a task has a reference to its group leader, we know it must be valid for
+ // the lifetime of the returned task reference.
+ unsafe { &*ptr.cast() }
+ }
+
+ /// Returns the PID of the given task.
+ pub fn pid(&self) -> Pid {
+ // SAFETY: By the type invariant, we know that `self.0` is valid.
+ unsafe { core::ptr::addr_of!((*self.0.get()).pid).read() }
+ }
+
+ /// Determines whether the given task has pending signals.
+ pub fn signal_pending(&self) -> bool {
+ // SAFETY: By the type invariant, we know that `self.0` is valid.
+ unsafe { bindings::signal_pending(self.0.get()) != 0 }
+ }
+
+ /// Starts a new kernel thread and runs it.
+ ///
+ /// # Examples
+ ///
+ /// Launches 10 threads and waits for them to complete.
+ ///
+ /// ```
+ /// use core::sync::atomic::{AtomicU32, Ordering};
+ /// use kernel::sync::{CondVar, Mutex};
+ /// use kernel::task::Task;
+ ///
+ /// kernel::init_static_sync! {
+ /// static COUNT: Mutex<u32> = 0;
+ /// static COUNT_IS_ZERO: CondVar;
+ /// }
+ ///
+ /// fn threadfn() {
+ /// pr_info!("Running from thread {}\n", Task::current().pid());
+ /// let mut guard = COUNT.lock();
+ /// *guard -= 1;
+ /// if *guard == 0 {
+ /// COUNT_IS_ZERO.notify_all();
+ /// }
+ /// }
+ ///
+ /// // Set count to 10 and spawn 10 threads.
+ /// *COUNT.lock() = 10;
+ /// for i in 0..10 {
+ /// Task::spawn(fmt!("test{i}"), threadfn).unwrap();
+ /// }
+ ///
+ /// // Wait for count to drop to zero.
+ /// let mut guard = COUNT.lock();
+ /// while (*guard != 0) {
+ /// COUNT_IS_ZERO.wait(&mut guard);
+ /// }
+ /// ```
+ pub fn spawn<T: FnOnce() + Send + 'static>(
+ name: fmt::Arguments<'_>,
+ func: T,
+ ) -> Result<ARef<Task>> {
+ unsafe extern "C" fn threadfn<T: FnOnce() + Send + 'static>(
+ arg: *mut core::ffi::c_void,
+ ) -> core::ffi::c_int {
+ // SAFETY: The thread argument is always a `Box<T>` because it is only called via the
+ // thread creation below.
+ let bfunc = unsafe { Box::<T>::from_pointer(arg) };
+ bfunc();
+ 0
+ }
+
+ let arg = Box::try_new(func)?.into_pointer();
+
+ // SAFETY: `arg` was just created with a call to `into_pointer` above.
+ let guard = ScopeGuard::new(|| unsafe {
+ Box::<T>::from_pointer(arg);
+ });
+
+ // SAFETY: The function pointer is always valid (as long as the module remains loaded).
+ // Ownership of `raw` is transferred to the new thread (if one is actually created), so it
+ // remains valid. Lastly, the C format string is a constant that require formatting as the
+ // one and only extra argument.
+ let ktask = from_kernel_err_ptr(unsafe {
+ bindings::kthread_create_on_node(
+ Some(threadfn::<T>),
+ arg as _,
+ bindings::NUMA_NO_NODE,
+ c_str!("%pA").as_char_ptr(),
+ &name as *const _ as *const core::ffi::c_void,
+ )
+ })?;
+
+ // SAFETY: Since the kthread creation succeeded and we haven't run it yet, we know the task
+ // is valid.
+ let task: ARef<_> = unsafe { &*(ktask as *const Task) }.into();
+
+ // Wakes up the thread, otherwise it won't run.
+ task.wake_up();
+
+ guard.dismiss();
+ Ok(task)
+ }
+
+ /// Wakes up the task.
+ pub fn wake_up(&self) {
+ // SAFETY: By the type invariant, we know that `self.0.get()` is non-null and valid.
+ // And `wake_up_process` is safe to be called for any valid task, even if the task is
+ // running.
+ unsafe { bindings::wake_up_process(self.0.get()) };
+ }
+}
+
+// SAFETY: The type invariants guarantee that `Task` is always ref-counted.
+unsafe impl AlwaysRefCounted for Task {
+ fn inc_ref(&self) {
+ // SAFETY: The existence of a shared reference means that the refcount is nonzero.
+ unsafe { bindings::get_task_struct(self.0.get()) };
+ }
+
+ unsafe fn dec_ref(obj: ptr::NonNull<Self>) {
+ // SAFETY: The safety requirements guarantee that the refcount is nonzero.
+ unsafe { bindings::put_task_struct(obj.cast().as_ptr()) }
+ }
+}
+
+/// A wrapper for a shared reference to [`Task`] that isn't [`Send`].
+///
+/// We make this explicitly not [`Send`] so that we can use it to represent the current thread
+/// without having to increment/decrement the task's reference count.
+///
+/// # Invariants
+///
+/// The wrapped [`Task`] remains valid for the lifetime of the object.
+pub struct TaskRef<'a> {
+ task: &'a Task,
+ _not_send: PhantomData<*mut ()>,
+}
+
+impl Deref for TaskRef<'_> {
+ type Target = Task;
+
+ fn deref(&self) -> &Self::Target {
+ self.task
+ }
+}
+
+impl From<TaskRef<'_>> for ARef<Task> {
+ fn from(t: TaskRef<'_>) -> Self {
+ t.deref().into()
+ }
+}
diff --git a/rust/kernel/types.rs b/rust/kernel/types.rs
new file mode 100644
index 000000000000..b1f73aeece0b
--- /dev/null
+++ b/rust/kernel/types.rs
@@ -0,0 +1,705 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Kernel types.
+//!
+//! C header: [`include/linux/types.h`](../../../../include/linux/types.h)
+
+use crate::{
+ bindings,
+ sync::{Ref, RefBorrow},
+};
+use alloc::boxed::Box;
+use core::{
+ cell::UnsafeCell,
+ marker::PhantomData,
+ mem::MaybeUninit,
+ ops::{self, Deref, DerefMut},
+ pin::Pin,
+ ptr::NonNull,
+};
+
+/// Permissions.
+///
+/// C header: [`include/uapi/linux/stat.h`](../../../../include/uapi/linux/stat.h)
+///
+/// C header: [`include/linux/stat.h`](../../../../include/linux/stat.h)
+pub struct Mode(bindings::umode_t);
+
+impl Mode {
+ /// Creates a [`Mode`] from an integer.
+ pub fn from_int(m: u16) -> Mode {
+ Mode(m)
+ }
+
+ /// Returns the mode as an integer.
+ pub fn as_int(&self) -> u16 {
+ self.0
+ }
+}
+
+/// Used to convert an object into a raw pointer that represents it.
+///
+/// It can eventually be converted back into the object. This is used to store objects as pointers
+/// in kernel data structures, for example, an implementation of
+/// [`Operations`][crate::file::Operations] in `struct
+/// file::private_data`.
+pub trait PointerWrapper {
+ /// Type of values borrowed between calls to [`PointerWrapper::into_pointer`] and
+ /// [`PointerWrapper::from_pointer`].
+ type Borrowed<'a>;
+
+ /// Returns the raw pointer.
+ fn into_pointer(self) -> *const core::ffi::c_void;
+
+ /// Returns a borrowed value.
+ ///
+ /// # Safety
+ ///
+ /// `ptr` must have been returned by a previous call to [`PointerWrapper::into_pointer`].
+ /// Additionally, [`PointerWrapper::from_pointer`] can only be called after *all* values
+ /// returned by [`PointerWrapper::borrow`] have been dropped.
+ unsafe fn borrow<'a>(ptr: *const core::ffi::c_void) -> Self::Borrowed<'a>;
+
+ /// Returns a mutably borrowed value.
+ ///
+ /// # Safety
+ ///
+ /// The passed pointer must come from a previous to [`PointerWrapper::into_pointer`], and no
+ /// other concurrent users of the pointer (except the ones derived from the returned value) run
+ /// at least until the returned [`ScopeGuard`] is dropped.
+ unsafe fn borrow_mut<T: PointerWrapper>(ptr: *const core::ffi::c_void) -> ScopeGuard<T, fn(T)> {
+ // SAFETY: The safety requirements ensure that `ptr` came from a previous call to
+ // `into_pointer`.
+ ScopeGuard::new_with_data(unsafe { T::from_pointer(ptr) }, |d| {
+ d.into_pointer();
+ })
+ }
+
+ /// Returns the instance back from the raw pointer.
+ ///
+ /// # Safety
+ ///
+ /// The passed pointer must come from a previous call to [`PointerWrapper::into_pointer()`].
+ unsafe fn from_pointer(ptr: *const core::ffi::c_void) -> Self;
+}
+
+impl<T: 'static> PointerWrapper for Box<T> {
+ type Borrowed<'a> = &'a T;
+
+ fn into_pointer(self) -> *const core::ffi::c_void {
+ Box::into_raw(self) as _
+ }
+
+ unsafe fn borrow<'a>(ptr: *const core::ffi::c_void) -> &'a T {
+ // SAFETY: The safety requirements for this function ensure that the object is still alive,
+ // so it is safe to dereference the raw pointer.
+ // The safety requirements also ensure that the object remains alive for the lifetime of
+ // the returned value.
+ unsafe { &*ptr.cast() }
+ }
+
+ unsafe fn from_pointer(ptr: *const core::ffi::c_void) -> Self {
+ // SAFETY: The passed pointer comes from a previous call to [`Self::into_pointer()`].
+ unsafe { Box::from_raw(ptr as _) }
+ }
+}
+
+impl<T: 'static> PointerWrapper for Ref<T> {
+ type Borrowed<'a> = RefBorrow<'a, T>;
+
+ fn into_pointer(self) -> *const core::ffi::c_void {
+ Ref::into_usize(self) as _
+ }
+
+ unsafe fn borrow<'a>(ptr: *const core::ffi::c_void) -> RefBorrow<'a, T> {
+ // SAFETY: The safety requirements for this function ensure that the underlying object
+ // remains valid for the lifetime of the returned value.
+ unsafe { Ref::borrow_usize(ptr as _) }
+ }
+
+ unsafe fn from_pointer(ptr: *const core::ffi::c_void) -> Self {
+ // SAFETY: The passed pointer comes from a previous call to [`Self::into_pointer()`].
+ unsafe { Ref::from_usize(ptr as _) }
+ }
+}
+
+impl<T: PointerWrapper + Deref> PointerWrapper for Pin<T> {
+ type Borrowed<'a> = T::Borrowed<'a>;
+
+ fn into_pointer(self) -> *const core::ffi::c_void {
+ // SAFETY: We continue to treat the pointer as pinned by returning just a pointer to it to
+ // the caller.
+ let inner = unsafe { Pin::into_inner_unchecked(self) };
+ inner.into_pointer()
+ }
+
+ unsafe fn borrow<'a>(ptr: *const core::ffi::c_void) -> Self::Borrowed<'a> {
+ // SAFETY: The safety requirements for this function are the same as the ones for
+ // `T::borrow`.
+ unsafe { T::borrow(ptr) }
+ }
+
+ unsafe fn from_pointer(p: *const core::ffi::c_void) -> Self {
+ // SAFETY: The object was originally pinned.
+ // The passed pointer comes from a previous call to `inner::into_pointer()`.
+ unsafe { Pin::new_unchecked(T::from_pointer(p)) }
+ }
+}
+
+impl<T> PointerWrapper for *mut T {
+ type Borrowed<'a> = *mut T;
+
+ fn into_pointer(self) -> *const core::ffi::c_void {
+ self as _
+ }
+
+ unsafe fn borrow<'a>(ptr: *const core::ffi::c_void) -> Self::Borrowed<'a> {
+ ptr as _
+ }
+
+ unsafe fn from_pointer(ptr: *const core::ffi::c_void) -> Self {
+ ptr as _
+ }
+}
+
+impl PointerWrapper for () {
+ type Borrowed<'a> = ();
+
+ fn into_pointer(self) -> *const core::ffi::c_void {
+ // We use 1 to be different from a null pointer.
+ 1usize as _
+ }
+
+ unsafe fn borrow<'a>(_: *const core::ffi::c_void) -> Self::Borrowed<'a> {}
+
+ unsafe fn from_pointer(_: *const core::ffi::c_void) -> Self {}
+}
+
+/// Runs a cleanup function/closure when dropped.
+///
+/// The [`ScopeGuard::dismiss`] function prevents the cleanup function from running.
+///
+/// # Examples
+///
+/// In the example below, we have multiple exit paths and we want to log regardless of which one is
+/// taken:
+/// ```
+/// # use kernel::ScopeGuard;
+/// fn example1(arg: bool) {
+/// let _log = ScopeGuard::new(|| pr_info!("example1 completed\n"));
+///
+/// if arg {
+/// return;
+/// }
+///
+/// pr_info!("Do something...\n");
+/// }
+///
+/// # example1(false);
+/// # example1(true);
+/// ```
+///
+/// In the example below, we want to log the same message on all early exits but a different one on
+/// the main exit path:
+/// ```
+/// # use kernel::ScopeGuard;
+/// fn example2(arg: bool) {
+/// let log = ScopeGuard::new(|| pr_info!("example2 returned early\n"));
+///
+/// if arg {
+/// return;
+/// }
+///
+/// // (Other early returns...)
+///
+/// log.dismiss();
+/// pr_info!("example2 no early return\n");
+/// }
+///
+/// # example2(false);
+/// # example2(true);
+/// ```
+///
+/// In the example below, we need a mutable object (the vector) to be accessible within the log
+/// function, so we wrap it in the [`ScopeGuard`]:
+/// ```
+/// # use kernel::ScopeGuard;
+/// fn example3(arg: bool) -> Result {
+/// let mut vec =
+/// ScopeGuard::new_with_data(Vec::new(), |v| pr_info!("vec had {} elements\n", v.len()));
+///
+/// vec.try_push(10u8)?;
+/// if arg {
+/// return Ok(());
+/// }
+/// vec.try_push(20u8)?;
+/// Ok(())
+/// }
+///
+/// # assert_eq!(example3(false), Ok(()));
+/// # assert_eq!(example3(true), Ok(()));
+/// ```
+///
+/// # Invariants
+///
+/// The value stored in the struct is nearly always `Some(_)`, except between
+/// [`ScopeGuard::dismiss`] and [`ScopeGuard::drop`]: in this case, it will be `None` as the value
+/// will have been returned to the caller. Since [`ScopeGuard::dismiss`] consumes the guard,
+/// callers won't be able to use it anymore.
+pub struct ScopeGuard<T, F: FnOnce(T)>(Option<(T, F)>);
+
+impl<T, F: FnOnce(T)> ScopeGuard<T, F> {
+ /// Creates a new guarded object wrapping the given data and with the given cleanup function.
+ pub fn new_with_data(data: T, cleanup_func: F) -> Self {
+ // INVARIANT: The struct is being initialised with `Some(_)`.
+ Self(Some((data, cleanup_func)))
+ }
+
+ /// Prevents the cleanup function from running and returns the guarded data.
+ pub fn dismiss(mut self) -> T {
+ // INVARIANT: This is the exception case in the invariant; it is not visible to callers
+ // because this function consumes `self`.
+ self.0.take().unwrap().0
+ }
+}
+
+impl ScopeGuard<(), Box<dyn FnOnce(())>> {
+ /// Creates a new guarded object with the given cleanup function.
+ pub fn new(cleanup: impl FnOnce()) -> ScopeGuard<(), impl FnOnce(())> {
+ ScopeGuard::new_with_data((), move |_| cleanup())
+ }
+}
+
+impl<T, F: FnOnce(T)> Deref for ScopeGuard<T, F> {
+ type Target = T;
+
+ fn deref(&self) -> &T {
+ // The type invariants guarantee that `unwrap` will succeed.
+ &self.0.as_ref().unwrap().0
+ }
+}
+
+impl<T, F: FnOnce(T)> DerefMut for ScopeGuard<T, F> {
+ fn deref_mut(&mut self) -> &mut T {
+ // The type invariants guarantee that `unwrap` will succeed.
+ &mut self.0.as_mut().unwrap().0
+ }
+}
+
+impl<T, F: FnOnce(T)> Drop for ScopeGuard<T, F> {
+ fn drop(&mut self) {
+ // Run the cleanup function if one is still present.
+ if let Some((data, cleanup)) = self.0.take() {
+ cleanup(data)
+ }
+ }
+}
+
+/// Stores an opaque value.
+///
+/// This is meant to be used with FFI objects that are never interpreted by Rust code.
+#[repr(transparent)]
+pub struct Opaque<T>(MaybeUninit<UnsafeCell<T>>);
+
+impl<T> Opaque<T> {
+ /// Creates a new opaque value.
+ pub const fn new(value: T) -> Self {
+ Self(MaybeUninit::new(UnsafeCell::new(value)))
+ }
+
+ /// Creates an uninitialised value.
+ pub const fn uninit() -> Self {
+ Self(MaybeUninit::uninit())
+ }
+
+ /// Returns a raw pointer to the opaque data.
+ pub fn get(&self) -> *mut T {
+ UnsafeCell::raw_get(self.0.as_ptr())
+ }
+}
+
+/// A bitmask.
+///
+/// It has a restriction that all bits must be the same, except one. For example, `0b1110111` and
+/// `0b1000` are acceptable masks.
+#[derive(Clone, Copy)]
+pub struct Bit<T> {
+ index: T,
+ inverted: bool,
+}
+
+/// Creates a bit mask with a single bit set.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::bit;
+/// let mut x = 0xfeu32;
+///
+/// assert_eq!(x & bit(0), 0);
+/// assert_eq!(x & bit(1), 2);
+/// assert_eq!(x & bit(2), 4);
+/// assert_eq!(x & bit(3), 8);
+///
+/// x |= bit(0);
+/// assert_eq!(x, 0xff);
+///
+/// x &= !bit(1);
+/// assert_eq!(x, 0xfd);
+///
+/// x &= !bit(7);
+/// assert_eq!(x, 0x7d);
+///
+/// let y: u64 = bit(34).into();
+/// assert_eq!(y, 0x400000000);
+///
+/// assert_eq!(y | bit(35), 0xc00000000);
+/// ```
+pub fn bit<T: Copy>(index: T) -> Bit<T> {
+ Bit {
+ index,
+ inverted: false,
+ }
+}
+
+impl<T: Copy> ops::Not for Bit<T> {
+ type Output = Self;
+ fn not(self) -> Self {
+ Self {
+ index: self.index,
+ inverted: !self.inverted,
+ }
+ }
+}
+
+/// Implemented by integer types that allow counting the number of trailing zeroes.
+pub trait TrailingZeros {
+ /// Returns the number of trailing zeroes in the binary representation of `self`.
+ fn trailing_zeros(&self) -> u32;
+}
+
+macro_rules! define_unsigned_number_traits {
+ ($type_name:ty) => {
+ impl TrailingZeros for $type_name {
+ fn trailing_zeros(&self) -> u32 {
+ <$type_name>::trailing_zeros(*self)
+ }
+ }
+
+ impl<T: Copy> core::convert::From<Bit<T>> for $type_name
+ where
+ Self: ops::Shl<T, Output = Self> + core::convert::From<u8> + ops::Not<Output = Self>,
+ {
+ fn from(v: Bit<T>) -> Self {
+ let c = Self::from(1u8) << v.index;
+ if v.inverted {
+ !c
+ } else {
+ c
+ }
+ }
+ }
+
+ impl<T: Copy> ops::BitAnd<Bit<T>> for $type_name
+ where
+ Self: ops::Shl<T, Output = Self> + core::convert::From<u8>,
+ {
+ type Output = Self;
+ fn bitand(self, rhs: Bit<T>) -> Self::Output {
+ self & Self::from(rhs)
+ }
+ }
+
+ impl<T: Copy> ops::BitOr<Bit<T>> for $type_name
+ where
+ Self: ops::Shl<T, Output = Self> + core::convert::From<u8>,
+ {
+ type Output = Self;
+ fn bitor(self, rhs: Bit<T>) -> Self::Output {
+ self | Self::from(rhs)
+ }
+ }
+
+ impl<T: Copy> ops::BitAndAssign<Bit<T>> for $type_name
+ where
+ Self: ops::Shl<T, Output = Self> + core::convert::From<u8>,
+ {
+ fn bitand_assign(&mut self, rhs: Bit<T>) {
+ *self &= Self::from(rhs)
+ }
+ }
+
+ impl<T: Copy> ops::BitOrAssign<Bit<T>> for $type_name
+ where
+ Self: ops::Shl<T, Output = Self> + core::convert::From<u8>,
+ {
+ fn bitor_assign(&mut self, rhs: Bit<T>) {
+ *self |= Self::from(rhs)
+ }
+ }
+ };
+}
+
+define_unsigned_number_traits!(u8);
+define_unsigned_number_traits!(u16);
+define_unsigned_number_traits!(u32);
+define_unsigned_number_traits!(u64);
+define_unsigned_number_traits!(usize);
+
+/// Returns an iterator over the set bits of `value`.
+///
+/// # Examples
+///
+/// ```
+/// use kernel::bits_iter;
+///
+/// let mut iter = bits_iter(5usize);
+/// assert_eq!(iter.next().unwrap(), 0);
+/// assert_eq!(iter.next().unwrap(), 2);
+/// assert!(iter.next().is_none());
+/// ```
+///
+/// ```
+/// use kernel::bits_iter;
+///
+/// fn print_bits(x: usize) {
+/// for bit in bits_iter(x) {
+/// pr_info!("{}\n", bit);
+/// }
+/// }
+///
+/// # print_bits(42);
+/// ```
+#[inline]
+pub fn bits_iter<T>(value: T) -> impl Iterator<Item = u32>
+where
+ T: core::cmp::PartialEq
+ + From<u8>
+ + ops::Shl<u32, Output = T>
+ + ops::Not<Output = T>
+ + ops::BitAndAssign
+ + TrailingZeros,
+{
+ struct BitIterator {
+ value: U,
+ }
+
+ impl Iterator for BitIterator
+ where
+ U: core::cmp::PartialEq
+ + From<u8>
+ + ops::Shl<u32, Output = U>
+ + ops::Not<Output = U>
+ + ops::BitAndAssign
+ + TrailingZeros,
+ {
+ type Item = u32;
+
+ #[inline]
+ fn next(&mut self) -> Option<u32> {
+ if self.value == U::from(0u8) {
+ return None;
+ }
+ let ret = self.value.trailing_zeros();
+ self.value &= !(U::from(1u8) << ret);
+ Some(ret)
+ }
+ }
+
+ BitIterator { value }
+}
+
+/// A trait for boolean types.
+///
+/// This is meant to be used in type states to allow boolean constraints in implementation blocks.
+/// In the example below, the implementation containing `MyType::set_value` could _not_ be
+/// constrained to type states containing `Writable = true` if `Writable` were a constant instead
+/// of a type.
+///
+/// # Safety
+///
+/// No additional implementations of [`Bool`] should be provided, as [`True`] and [`False`] are
+/// already provided.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::{Bool, False, True};
+/// use core::marker::PhantomData;
+///
+/// // Type state specifies whether the type is writable.
+/// trait MyTypeState {
+/// type Writable: Bool;
+/// }
+///
+/// // In state S1, the type is writable.
+/// struct S1;
+/// impl MyTypeState for S1 {
+/// type Writable = True;
+/// }
+///
+/// // In state S2, the type is not writable.
+/// struct S2;
+/// impl MyTypeState for S2 {
+/// type Writable = False;
+/// }
+///
+/// struct MyType<T: MyTypeState> {
+/// value: u32,
+/// _p: PhantomData<T>,
+/// }
+///
+/// impl<T: MyTypeState> MyType<T> {
+/// fn new(value: u32) -> Self {
+/// Self {
+/// value,
+/// _p: PhantomData,
+/// }
+/// }
+/// }
+///
+/// // This implementation block only applies if the type state is writable.
+/// impl<T> MyType<T>
+/// where
+/// T: MyTypeState<Writable = True>,
+/// {
+/// fn set_value(&mut self, v: u32) {
+/// self.value = v;
+/// }
+/// }
+///
+/// let mut x = MyType::<S1>::new(10);
+/// let mut y = MyType::<S2>::new(20);
+///
+/// x.set_value(30);
+///
+/// // The code below fails to compile because `S2` is not writable.
+/// // y.set_value(40);
+/// ```
+pub unsafe trait Bool {}
+
+/// Represents the `true` value for types with [`Bool`] bound.
+pub struct True;
+
+// SAFETY: This is one of the only two implementations of `Bool`.
+unsafe impl Bool for True {}
+
+/// Represents the `false` value for types wth [`Bool`] bound.
+pub struct False;
+
+// SAFETY: This is one of the only two implementations of `Bool`.
+unsafe impl Bool for False {}
+
+/// Types that are _always_ reference counted.
+///
+/// It allows such types to define their own custom ref increment and decrement functions.
+/// Additionally, it allows users to convert from a shared reference `&T` to an owned reference
+/// [`ARef<T>`].
+///
+/// This is usually implemented by wrappers to existing structures on the C side of the code. For
+/// Rust code, the recommendation is to use [`Ref`] to create reference-counted instances of a
+/// type.
+///
+/// # Safety
+///
+/// Implementers must ensure that increments to the reference count keeps the object alive in
+/// memory at least until a matching decrement performed.
+///
+/// Implementers must also ensure that all instances are reference-counted. (Otherwise they
+/// won't be able to honour the requirement that [`AlwaysRefCounted::inc_ref`] keep the object
+/// alive.)
+pub unsafe trait AlwaysRefCounted {
+ /// Increments the reference count on the object.
+ fn inc_ref(&self);
+
+ /// Decrements the reference count on the object.
+ ///
+ /// Frees the object when the count reaches zero.
+ ///
+ /// # Safety
+ ///
+ /// Callers must ensure that there was a previous matching increment to the reference count,
+ /// and that the object is no longer used after its reference count is decremented (as it may
+ /// result in the object being freed), unless the caller owns another increment on the refcount
+ /// (e.g., it calls [`AlwaysRefCounted::inc_ref`] twice, then calls
+ /// [`AlwaysRefCounted::dec_ref`] once).
+ unsafe fn dec_ref(obj: NonNull<Self>);
+}
+
+/// An owned reference to an always-reference-counted object.
+///
+/// The object's reference count is automatically decremented when an instance of [`ARef`] is
+/// dropped. It is also automatically incremented when a new instance is created via
+/// [`ARef::clone`].
+///
+/// # Invariants
+///
+/// The pointer stored in `ptr` is non-null and valid for the lifetime of the [`ARef`] instance. In
+/// particular, the [`ARef`] instance owns an increment on underlying object's reference count.
+pub struct ARef<T: AlwaysRefCounted> {
+ ptr: NonNull<T>,
+ _p: PhantomData<T>,
+}
+
+impl<T: AlwaysRefCounted> ARef<T> {
+ /// Creates a new instance of [`ARef`].
+ ///
+ /// It takes over an increment of the reference count on the underlying object.
+ ///
+ /// # Safety
+ ///
+ /// Callers must ensure that the reference count was incremented at least once, and that they
+ /// are properly relinquishing one increment. That is, if there is only one increment, callers
+ /// must not use the underlying object anymore -- it is only safe to do so via the newly
+ /// created [`ARef`].
+ pub unsafe fn from_raw(ptr: NonNull<T>) -> Self {
+ // INVARIANT: The safety requirements guarantee that the new instance now owns the
+ // increment on the refcount.
+ Self {
+ ptr,
+ _p: PhantomData,
+ }
+ }
+}
+
+impl<T: AlwaysRefCounted> Clone for ARef<T> {
+ fn clone(&self) -> Self {
+ self.inc_ref();
+ // SAFETY: We just incremented the refcount above.
+ unsafe { Self::from_raw(self.ptr) }
+ }
+}
+
+impl<T: AlwaysRefCounted> Deref for ARef<T> {
+ type Target = T;
+
+ fn deref(&self) -> &Self::Target {
+ // SAFETY: The type invariants guarantee that the object is valid.
+ unsafe { self.ptr.as_ref() }
+ }
+}
+
+impl<T: AlwaysRefCounted> From<&T> for ARef<T> {
+ fn from(b: &T) -> Self {
+ b.inc_ref();
+ // SAFETY: We just incremented the refcount above.
+ unsafe { Self::from_raw(NonNull::from(b)) }
+ }
+}
+
+impl<T: AlwaysRefCounted> Drop for ARef<T> {
+ fn drop(&mut self) {
+ // SAFETY: The type invariants guarantee that the `ARef` owns the reference we're about to
+ // decrement.
+ unsafe { T::dec_ref(self.ptr) };
+ }
+}
+
+/// A sum type that always holds either a value of type `L` or `R`.
+pub enum Either<L, R> {
+ /// Constructs an instance of [`Either`] containing a value of type `L`.
+ Left(L),
+
+ /// Constructs an instance of [`Either`] containing a value of type `R`.
+ Right(R),
+}
diff --git a/rust/kernel/unsafe_list.rs b/rust/kernel/unsafe_list.rs
new file mode 100644
index 000000000000..df496667c033
--- /dev/null
+++ b/rust/kernel/unsafe_list.rs
@@ -0,0 +1,680 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Intrusive circular doubly-linked lists.
+//!
+//! We don't use the C version for two main reasons:
+//! - Next/prev pointers do not support `?Sized` types, so wouldn't be able to have a list of, for
+//! example, `dyn Trait`.
+//! - It would require the list head to be pinned (in addition to the list entries).
+
+use core::{cell::UnsafeCell, iter, marker::PhantomPinned, mem::MaybeUninit, ptr::NonNull};
+
+/// An intrusive circular doubly-linked list.
+///
+/// Membership of elements of the list must be tracked by the owner of the list.
+///
+/// While elements of the list must remain pinned while in the list, the list itself does not
+/// require pinning. In other words, users are allowed to move instances of [`List`].
+///
+/// # Invariants
+///
+/// The links of an entry are wrapped in [`UnsafeCell`] and they are acessible when the list itself
+/// is. For example, when a thread has a mutable reference to a list, it may also safely get
+/// mutable references to the links of the elements in the list.
+///
+/// The links of an entry are also wrapped in [`MaybeUninit`] and they are initialised when they
+/// are present in a list. Otherwise they are uninitialised.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::unsafe_list::{Adapter, Links, List};
+///
+/// struct Example {
+/// v: usize,
+/// links: Links<Example>,
+/// }
+///
+/// // SAFETY: This adapter is the only one that uses `Example::links`.
+/// unsafe impl Adapter for Example {
+/// type EntryType = Self;
+/// fn to_links(obj: &Self) -> &Links<Self> {
+/// &obj.links
+/// }
+/// }
+///
+/// let a = Example {
+/// v: 0,
+/// links: Links::new(),
+/// };
+/// let b = Example {
+/// v: 1,
+/// links: Links::new(),
+/// };
+///
+/// let mut list = List::<Example>::new();
+/// assert!(list.is_empty());
+///
+/// // SAFETY: `a` was declared above, it's not in any lists yet, is never moved, and outlives the
+/// // list.
+/// unsafe { list.push_back(&a) };
+///
+/// // SAFETY: `b` was declared above, it's not in any lists yet, is never moved, and outlives the
+/// // list.
+/// unsafe { list.push_back(&b) };
+///
+/// assert!(core::ptr::eq(&a, list.front().unwrap().as_ptr()));
+/// assert!(core::ptr::eq(&b, list.back().unwrap().as_ptr()));
+///
+/// for (i, e) in list.iter().enumerate() {
+/// assert_eq!(i, e.v);
+/// }
+///
+/// for e in &list {
+/// pr_info!("{}", e.v);
+/// }
+///
+/// // SAFETY: `b` was added to the list above and wasn't removed yet.
+/// unsafe { list.remove(&b) };
+///
+/// assert!(core::ptr::eq(&a, list.front().unwrap().as_ptr()));
+/// assert!(core::ptr::eq(&a, list.back().unwrap().as_ptr()));
+/// ```
+pub struct List<A: Adapter + ?Sized> {
+ first: Option<NonNull<A::EntryType>>,
+}
+
+// SAFETY: The list is itself can be safely sent to other threads but we restrict it to being `Send`
+// only when its entries are also `Send`.
+unsafe impl<A: Adapter + ?Sized> Send for List<A> where A::EntryType: Send {}
+
+// SAFETY: The list is itself usable from other threads via references but we restrict it to being
+// `Sync` only when its entries are also `Sync`.
+unsafe impl<A: Adapter + ?Sized> Sync for List<A> where A::EntryType: Sync {}
+
+impl<A: Adapter + ?Sized> List<A> {
+ /// Constructs a new empty list.
+ pub const fn new() -> Self {
+ Self { first: None }
+ }
+
+ /// Determines if the list is empty.
+ pub fn is_empty(&self) -> bool {
+ self.first.is_none()
+ }
+
+ /// Inserts the only entry to a list.
+ ///
+ /// This must only be called when the list is empty.
+ pub fn insert_only_entry(&mut self, obj: &A::EntryType) {
+ let obj_ptr = NonNull::from(obj);
+
+ // SAFETY: We have mutable access to the list, so we also have access to the entry
+ // we're about to insert (and it's not in any other lists per the function safety
+ // requirements).
+ let obj_inner = unsafe { &mut *A::to_links(obj).0.get() };
+
+ // INVARIANTS: All fields of the links of the newly-inserted object are initialised
+ // below.
+ obj_inner.write(LinksInner {
+ next: obj_ptr,
+ prev: obj_ptr,
+ _pin: PhantomPinned,
+ });
+ self.first = Some(obj_ptr);
+ }
+
+ /// Adds the given object to the end of the list.
+ ///
+ /// # Safety
+ ///
+ /// Callers must ensure that:
+ /// - The object is not currently in any lists.
+ /// - The object remains alive until it is removed from the list.
+ /// - The object is not moved until it is removed from the list.
+ pub unsafe fn push_back(&mut self, obj: &A::EntryType) {
+ if let Some(first) = self.first {
+ // SAFETY: The previous entry to the first one is necessarily present in the list (it
+ // may in fact be the first entry itself as this is a circular list). The safety
+ // requirements of this function regarding `obj` satisfy those of `insert_after`.
+ unsafe { self.insert_after(self.inner_ref(first).prev, obj) };
+ } else {
+ self.insert_only_entry(obj);
+ }
+ }
+
+ /// Adds the given object to the beginning of the list.
+ ///
+ /// # Safety
+ ///
+ /// Callers must ensure that:
+ /// - The object is not currently in any lists.
+ /// - The object remains alive until it is removed from the list.
+ /// - The object is not moved until it is removed from the list.
+ pub unsafe fn push_front(&mut self, obj: &A::EntryType) {
+ if let Some(first) = self.first {
+ // SAFETY: The safety requirements of this function regarding `obj` satisfy those of
+ // `insert_before`. Additionally, `first` is in the list.
+ unsafe { self.insert_before(first, obj) };
+ } else {
+ self.insert_only_entry(obj);
+ }
+ }
+
+ /// Removes the given object from the list.
+ ///
+ /// # Safety
+ ///
+ /// The object must be in the list. In other words, the object must have previously been
+ /// inserted into this list and not removed yet.
+ pub unsafe fn remove(&mut self, entry: &A::EntryType) {
+ // SAFETY: Per the function safety requirements, `entry` is in the list.
+ let inner = unsafe { self.inner_ref(NonNull::from(entry)) };
+ let next = inner.next;
+ let prev = inner.prev;
+
+ // SAFETY: We have mutable access to the list, so we also have access to the entry we're
+ // about to remove (which we know is in the list per the function safety requirements).
+ let inner = unsafe { &mut *A::to_links(entry).0.get() };
+
+ // SAFETY: Since the entry was in the list, it was initialised.
+ unsafe { inner.assume_init_drop() };
+
+ if core::ptr::eq(next.as_ptr(), entry) {
+ // Removing the only element.
+ self.first = None;
+ } else {
+ // SAFETY: `prev` is in the list because it is pointed at by the entry being removed.
+ unsafe { self.inner(prev).next = next };
+ // SAFETY: `next` is in the list because it is pointed at by the entry being removed.
+ unsafe { self.inner(next).prev = prev };
+
+ if core::ptr::eq(self.first.unwrap().as_ptr(), entry) {
+ // Update the pointer to the first element as we're removing it.
+ self.first = Some(next);
+ }
+ }
+ }
+
+ /// Adds the given object after another object already in the list.
+ ///
+ /// # Safety
+ ///
+ /// Callers must ensure that:
+ /// - The existing object is currently in the list.
+ /// - The new object is not currently in any lists.
+ /// - The new object remains alive until it is removed from the list.
+ /// - The new object is not moved until it is removed from the list.
+ pub unsafe fn insert_after(&mut self, existing: NonNull<A::EntryType>, new: &A::EntryType) {
+ // SAFETY: We have mutable access to the list, so we also have access to the entry we're
+ // about to insert (and it's not in any other lists per the function safety requirements).
+ let new_inner = unsafe { &mut *A::to_links(new).0.get() };
+
+ // SAFETY: Per the function safety requirements, `existing` is in the list.
+ let existing_inner = unsafe { self.inner(existing) };
+ let next = existing_inner.next;
+
+ // INVARIANTS: All fields of the links of the newly-inserted object are initialised below.
+ new_inner.write(LinksInner {
+ next,
+ prev: existing,
+ _pin: PhantomPinned,
+ });
+
+ existing_inner.next = NonNull::from(new);
+
+ // SAFETY: `next` is in the list because it's pointed at by the existing entry.
+ unsafe { self.inner(next).prev = NonNull::from(new) };
+ }
+
+ /// Adds the given object before another object already in the list.
+ ///
+ /// # Safety
+ ///
+ /// Callers must ensure that:
+ /// - The existing object is currently in the list.
+ /// - The new object is not currently in any lists.
+ /// - The new object remains alive until it is removed from the list.
+ /// - The new object is not moved until it is removed from the list.
+ pub unsafe fn insert_before(&mut self, existing: NonNull<A::EntryType>, new: &A::EntryType) {
+ // SAFETY: The safety requirements of this function satisfy those of `insert_after`.
+ unsafe { self.insert_after(self.inner_ref(existing).prev, new) };
+
+ if self.first.unwrap() == existing {
+ // Update the pointer to the first element as we're inserting before it.
+ self.first = Some(NonNull::from(new));
+ }
+ }
+
+ /// Returns the first element of the list, if one exists.
+ pub fn front(&self) -> Option<NonNull<A::EntryType>> {
+ self.first
+ }
+
+ /// Returns the last element of the list, if one exists.
+ pub fn back(&self) -> Option<NonNull<A::EntryType>> {
+ // SAFETY: Having a pointer to it guarantees that the object is in the list.
+ self.first.map(|f| unsafe { self.inner_ref(f).prev })
+ }
+
+ /// Returns an iterator for the list starting at the first entry.
+ pub fn iter(&self) -> Iterator<'_, A> {
+ Iterator::new(self.cursor_front())
+ }
+
+ /// Returns an iterator for the list starting at the last entry.
+ pub fn iter_back(&self) -> impl iter::DoubleEndedIterator<Item = &'_ A::EntryType> {
+ Iterator::new(self.cursor_back())
+ }
+
+ /// Returns a cursor starting on the first (front) element of the list.
+ pub fn cursor_front(&self) -> Cursor<'_, A> {
+ // SAFETY: `front` is in the list (or is `None`) because we've read it from the list head
+ // and the list cannot have changed because we hold a shared reference to it.
+ unsafe { Cursor::new(self, self.front()) }
+ }
+
+ /// Returns a cursor starting on the last (back) element of the list.
+ pub fn cursor_back(&self) -> Cursor<'_, A> {
+ // SAFETY: `back` is in the list (or is `None`) because we've read it from the list head
+ // and the list cannot have changed because we hold a shared reference to it.
+ unsafe { Cursor::new(self, self.back()) }
+ }
+
+ /// Returns a mutable reference to the links of a given object.
+ ///
+ /// # Safety
+ ///
+ /// Callers must ensure that the element is in the list.
+ unsafe fn inner(&mut self, ptr: NonNull<A::EntryType>) -> &mut LinksInner<A::EntryType> {
+ // SAFETY: The safety requirements guarantee that we the links are initialised because
+ // that's part of the type invariants. Additionally, the type invariants also guarantee
+ // that having a mutable reference to the list guarantees that the links are mutably
+ // accessible as well.
+ unsafe { (*A::to_links(ptr.as_ref()).0.get()).assume_init_mut() }
+ }
+
+ /// Returns a shared reference to the links of a given object.
+ ///
+ /// # Safety
+ ///
+ /// Callers must ensure that the element is in the list.
+ unsafe fn inner_ref(&self, ptr: NonNull<A::EntryType>) -> &LinksInner<A::EntryType> {
+ // SAFETY: The safety requirements guarantee that we the links are initialised because
+ // that's part of the type invariants. Additionally, the type invariants also guarantee
+ // that having a shared reference to the list guarantees that the links are accessible in
+ // shared mode as well.
+ unsafe { (*A::to_links(ptr.as_ref()).0.get()).assume_init_ref() }
+ }
+}
+
+impl<'a, A: Adapter + ?Sized> iter::IntoIterator for &'a List<A> {
+ type Item = &'a A::EntryType;
+ type IntoIter = Iterator<'a, A>;
+ fn into_iter(self) -> Self::IntoIter {
+ self.iter()
+ }
+}
+
+/// An iterator for the linked list.
+pub struct Iterator<'a, A: Adapter + ?Sized> {
+ cursor: Cursor<'a, A>,
+}
+
+impl<'a, A: Adapter + ?Sized> Iterator<'a, A> {
+ fn new(cursor: Cursor<'a, A>) -> Self {
+ Self { cursor }
+ }
+}
+
+impl<'a, A: Adapter + ?Sized> iter::Iterator for Iterator<'a, A> {
+ type Item = &'a A::EntryType;
+
+ fn next(&mut self) -> Option<Self::Item> {
+ let ret = self.cursor.current()?;
+ self.cursor.move_next();
+ Some(ret)
+ }
+}
+
+impl<A: Adapter + ?Sized> iter::DoubleEndedIterator for Iterator<'_, A> {
+ fn next_back(&mut self) -> Option<Self::Item> {
+ let ret = self.cursor.current()?;
+ self.cursor.move_prev();
+ Some(ret)
+ }
+}
+
+/// A linked-list adapter.
+///
+/// It is a separate type (as opposed to implemented by the type of the elements of the list)
+/// so that a given type can be inserted into multiple lists at the same time; in such cases, each
+/// list needs its own adapter that returns a different pointer to links.
+///
+/// It may, however, be implemented by the type itself to be inserted into lists, which makes it
+/// more readable.
+///
+/// # Safety
+///
+/// Implementers must ensure that the links returned by [`Adapter::to_links`] are unique to the
+/// adapter. That is, different adapters must return different links for a given object.
+///
+/// The reason for this requirement is to avoid confusion that may lead to UB. In particular, if
+/// two adapters were to use the same links, a user may have two lists (one for each adapter) and
+/// try to insert the same object into both at the same time; although this clearly violates the
+/// list safety requirements (e.g., those in [`List::push_back`]), for users to notice it, they'd
+/// have to dig into the details of the two adapters.
+///
+/// By imposing the requirement on the adapter, we make it easier for users to check compliance
+/// with the requirements when using the list.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::unsafe_list::{Adapter, Links, List};
+///
+/// struct Example {
+/// a: u32,
+/// b: u32,
+/// links1: Links<Example>,
+/// links2: Links<Example>,
+/// }
+///
+/// // SAFETY: This adapter is the only one that uses `Example::links1`.
+/// unsafe impl Adapter for Example {
+/// type EntryType = Self;
+/// fn to_links(obj: &Self) -> &Links<Self> {
+/// &obj.links1
+/// }
+/// }
+///
+/// struct ExampleAdapter;
+///
+/// // SAFETY: This adapter is the only one that uses `Example::links2`.
+/// unsafe impl Adapter for ExampleAdapter {
+/// type EntryType = Example;
+/// fn to_links(obj: &Example) -> &Links<Example> {
+/// &obj.links2
+/// }
+/// }
+///
+/// static LIST1: List<Example> = List::new();
+/// static LIST2: List<ExampleAdapter> = List::new();
+/// ```
+pub unsafe trait Adapter {
+ /// The type of the enties in the list.
+ type EntryType: ?Sized;
+
+ /// Retrieves the linked list links for the given object.
+ fn to_links(obj: &Self::EntryType) -> &Links<Self::EntryType>;
+}
+
+struct LinksInner<T: ?Sized> {
+ next: NonNull<T>,
+ prev: NonNull<T>,
+ _pin: PhantomPinned,
+}
+
+/// Links of a linked list.
+///
+/// List entries need one of these per concurrent list.
+pub struct Links<T: ?Sized>(UnsafeCell<MaybeUninit<LinksInner<T>>>);
+
+// SAFETY: `Links` can be safely sent to other threads but we restrict it to being `Send` only when
+// the list entries it points to are also `Send`.
+unsafe impl<T: ?Sized> Send for Links<T> {}
+
+// SAFETY: `Links` is usable from other threads via references but we restrict it to being `Sync`
+// only when the list entries it points to are also `Sync`.
+unsafe impl<T: ?Sized> Sync for Links<T> {}
+
+impl<T: ?Sized> Links<T> {
+ /// Constructs a new instance of the linked-list links.
+ pub const fn new() -> Self {
+ Self(UnsafeCell::new(MaybeUninit::uninit()))
+ }
+}
+
+pub(crate) struct CommonCursor<A: Adapter + ?Sized> {
+ pub(crate) cur: Option<NonNull<A::EntryType>>,
+}
+
+impl<A: Adapter + ?Sized> CommonCursor<A> {
+ pub(crate) fn new(cur: Option<NonNull<A::EntryType>>) -> Self {
+ Self { cur }
+ }
+
+ /// Moves the cursor to the next entry of the list.
+ ///
+ /// # Safety
+ ///
+ /// Callers must ensure that the cursor is either [`None`] or points to an entry that is in
+ /// `list`.
+ pub(crate) unsafe fn move_next(&mut self, list: &List<A>) {
+ match self.cur.take() {
+ None => self.cur = list.first,
+ Some(cur) => {
+ if let Some(head) = list.first {
+ // SAFETY: Per the function safety requirements, `cur` is in the list.
+ let links = unsafe { list.inner_ref(cur) };
+ if links.next != head {
+ self.cur = Some(links.next);
+ }
+ }
+ }
+ }
+ }
+
+ /// Moves the cursor to the previous entry of the list.
+ ///
+ /// # Safety
+ ///
+ /// Callers must ensure that the cursor is either [`None`] or points to an entry that is in
+ /// `list`.
+ pub(crate) unsafe fn move_prev(&mut self, list: &List<A>) {
+ match list.first {
+ None => self.cur = None,
+ Some(head) => {
+ let next = match self.cur.take() {
+ None => head,
+ Some(cur) => {
+ if cur == head {
+ return;
+ }
+ cur
+ }
+ };
+ // SAFETY: `next` is either `head` or `cur`. The former is in the list because it's
+ // its head; the latter is in the list per the function safety requirements.
+ self.cur = Some(unsafe { list.inner_ref(next) }.prev);
+ }
+ }
+ }
+}
+
+/// A list cursor that allows traversing a linked list and inspecting elements.
+pub struct Cursor<'a, A: Adapter + ?Sized> {
+ cursor: CommonCursor<A>,
+ list: &'a List<A>,
+}
+
+impl<'a, A: Adapter + ?Sized> Cursor<'a, A> {
+ /// Creates a new cursor.
+ ///
+ /// # Safety
+ ///
+ /// Callers must ensure that `cur` is either [`None`] or points to an entry in `list`.
+ pub(crate) unsafe fn new(list: &'a List<A>, cur: Option<NonNull<A::EntryType>>) -> Self {
+ Self {
+ list,
+ cursor: CommonCursor::new(cur),
+ }
+ }
+
+ /// Returns the element the cursor is currently positioned on.
+ pub fn current(&self) -> Option<&'a A::EntryType> {
+ let cur = self.cursor.cur?;
+ // SAFETY: `cursor` starts off in the list and only changes within the list. Additionally,
+ // the list cannot change because we hold a shared reference to it, so the cursor is always
+ // within the list.
+ Some(unsafe { cur.as_ref() })
+ }
+
+ /// Moves the cursor to the next element.
+ pub fn move_next(&mut self) {
+ // SAFETY: `cursor` starts off in the list and only changes within the list. Additionally,
+ // the list cannot change because we hold a shared reference to it, so the cursor is always
+ // within the list.
+ unsafe { self.cursor.move_next(self.list) };
+ }
+
+ /// Moves the cursor to the previous element.
+ pub fn move_prev(&mut self) {
+ // SAFETY: `cursor` starts off in the list and only changes within the list. Additionally,
+ // the list cannot change because we hold a shared reference to it, so the cursor is always
+ // within the list.
+ unsafe { self.cursor.move_prev(self.list) };
+ }
+}
+
+#[cfg(test)]
+mod tests {
+ use alloc::{boxed::Box, vec::Vec};
+ use core::ptr::NonNull;
+
+ struct Example {
+ links: super::Links<Self>,
+ }
+
+ // SAFETY: This is the only adapter that uses `Example::links`.
+ unsafe impl super::Adapter for Example {
+ type EntryType = Self;
+ fn to_links(obj: &Self) -> &super::Links<Self> {
+ &obj.links
+ }
+ }
+
+ fn build_vector(size: usize) -> Vec<Box<Example>> {
+ let mut v = Vec::new();
+ v.reserve(size);
+ for _ in 0..size {
+ v.push(Box::new(Example {
+ links: super::Links::new(),
+ }));
+ }
+ v
+ }
+
+ #[track_caller]
+ fn assert_list_contents(v: &[Box<Example>], list: &super::List<Example>) {
+ let n = v.len();
+
+ // Assert that the list is ok going forward.
+ let mut count = 0;
+ for (i, e) in list.iter().enumerate() {
+ assert!(core::ptr::eq(e, &*v[i]));
+ count += 1;
+ }
+ assert_eq!(count, n);
+
+ // Assert that the list is ok going backwards.
+ let mut count = 0;
+ for (i, e) in list.iter_back().rev().enumerate() {
+ assert!(core::ptr::eq(e, &*v[n - 1 - i]));
+ count += 1;
+ }
+ assert_eq!(count, n);
+ }
+
+ #[track_caller]
+ fn test_each_element(
+ min_len: usize,
+ max_len: usize,
+ test: impl Fn(&mut Vec<Box<Example>>, &mut super::List<Example>, usize, Box<Example>),
+ ) {
+ for n in min_len..=max_len {
+ for i in 0..n {
+ let extra = Box::new(Example {
+ links: super::Links::new(),
+ });
+ let mut v = build_vector(n);
+ let mut list = super::List::<Example>::new();
+
+ // Build list.
+ for j in 0..n {
+ // SAFETY: The entry was allocated above, it's not in any lists yet, is never
+ // moved, and outlives the list.
+ unsafe { list.push_back(&v[j]) };
+ }
+
+ // Call the test case.
+ test(&mut v, &mut list, i, extra);
+
+ // Check that the list is ok.
+ assert_list_contents(&v, &list);
+ }
+ }
+ }
+
+ #[test]
+ fn test_push_back() {
+ const MAX: usize = 10;
+ let v = build_vector(MAX);
+ let mut list = super::List::<Example>::new();
+
+ for n in 1..=MAX {
+ // SAFETY: The entry was allocated above, it's not in any lists yet, is never moved,
+ // and outlives the list.
+ unsafe { list.push_back(&v[n - 1]) };
+ assert_list_contents(&v[..n], &list);
+ }
+ }
+
+ #[test]
+ fn test_push_front() {
+ const MAX: usize = 10;
+ let v = build_vector(MAX);
+ let mut list = super::List::<Example>::new();
+
+ for n in 1..=MAX {
+ // SAFETY: The entry was allocated above, it's not in any lists yet, is never moved,
+ // and outlives the list.
+ unsafe { list.push_front(&v[MAX - n]) };
+ assert_list_contents(&v[MAX - n..], &list);
+ }
+ }
+
+ #[test]
+ fn test_one_removal() {
+ test_each_element(1, 10, |v, list, i, _| {
+ // Remove the i-th element.
+ // SAFETY: The i-th element was added to the list above, and wasn't removed yet.
+ unsafe { list.remove(&v[i]) };
+ v.remove(i);
+ });
+ }
+
+ #[test]
+ fn test_one_insert_after() {
+ test_each_element(1, 10, |v, list, i, extra| {
+ // Insert after the i-th element.
+ // SAFETY: The i-th element was added to the list above, and wasn't removed yet.
+ // Additionally, the new element isn't in any list yet, isn't moved, and outlives
+ // the list.
+ unsafe { list.insert_after(NonNull::from(&*v[i]), &*extra) };
+ v.insert(i + 1, extra);
+ });
+ }
+
+ #[test]
+ fn test_one_insert_before() {
+ test_each_element(1, 10, |v, list, i, extra| {
+ // Insert before the i-th element.
+ // SAFETY: The i-th element was added to the list above, and wasn't removed yet.
+ // Additionally, the new element isn't in any list yet, isn't moved, and outlives
+ // the list.
+ unsafe { list.insert_before(NonNull::from(&*v[i]), &*extra) };
+ v.insert(i, extra);
+ });
+ }
+}
diff --git a/rust/kernel/user_ptr.rs b/rust/kernel/user_ptr.rs
new file mode 100644
index 000000000000..0bc2c7f1331e
--- /dev/null
+++ b/rust/kernel/user_ptr.rs
@@ -0,0 +1,175 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! User pointers.
+//!
+//! C header: [`include/linux/uaccess.h`](../../../../include/linux/uaccess.h)
+
+use crate::{
+ bindings,
+ error::code::*,
+ io_buffer::{IoBufferReader, IoBufferWriter},
+ Result,
+};
+use alloc::vec::Vec;
+
+/// A reference to an area in userspace memory, which can be either
+/// read-only or read-write.
+///
+/// All methods on this struct are safe: invalid pointers return
+/// `EFAULT`. Concurrent access, *including data races to/from userspace
+/// memory*, is permitted, because fundamentally another userspace
+/// thread/process could always be modifying memory at the same time
+/// (in the same way that userspace Rust's [`std::io`] permits data races
+/// with the contents of files on disk). In the presence of a race, the
+/// exact byte values read/written are unspecified but the operation is
+/// well-defined. Kernelspace code should validate its copy of data
+/// after completing a read, and not expect that multiple reads of the
+/// same address will return the same value.
+///
+/// All APIs enforce the invariant that a given byte of memory from userspace
+/// may only be read once. By preventing double-fetches we avoid TOCTOU
+/// vulnerabilities. This is accomplished by taking `self` by value to prevent
+/// obtaining multiple readers on a given [`UserSlicePtr`], and the readers
+/// only permitting forward reads.
+///
+/// Constructing a [`UserSlicePtr`] performs no checks on the provided
+/// address and length, it can safely be constructed inside a kernel thread
+/// with no current userspace process. Reads and writes wrap the kernel APIs
+/// `copy_from_user` and `copy_to_user`, which check the memory map of the
+/// current process and enforce that the address range is within the user
+/// range (no additional calls to `access_ok` are needed).
+///
+/// [`std::io`]: https://doc.rust-lang.org/std/io/index.html
+pub struct UserSlicePtr(*mut core::ffi::c_void, usize);
+
+impl UserSlicePtr {
+ /// Constructs a user slice from a raw pointer and a length in bytes.
+ ///
+ /// # Safety
+ ///
+ /// Callers must be careful to avoid time-of-check-time-of-use
+ /// (TOCTOU) issues. The simplest way is to create a single instance of
+ /// [`UserSlicePtr`] per user memory block as it reads each byte at
+ /// most once.
+ pub unsafe fn new(ptr: *mut core::ffi::c_void, length: usize) -> Self {
+ UserSlicePtr(ptr, length)
+ }
+
+ /// Reads the entirety of the user slice.
+ ///
+ /// Returns `EFAULT` if the address does not currently point to
+ /// mapped, readable memory.
+ pub fn read_all(self) -> Result<Vec<u8>> {
+ self.reader().read_all()
+ }
+
+ /// Constructs a [`UserSlicePtrReader`].
+ pub fn reader(self) -> UserSlicePtrReader {
+ UserSlicePtrReader(self.0, self.1)
+ }
+
+ /// Writes the provided slice into the user slice.
+ ///
+ /// Returns `EFAULT` if the address does not currently point to
+ /// mapped, writable memory (in which case some data from before the
+ /// fault may be written), or `data` is larger than the user slice
+ /// (in which case no data is written).
+ pub fn write_all(self, data: &[u8]) -> Result {
+ self.writer().write_slice(data)
+ }
+
+ /// Constructs a [`UserSlicePtrWriter`].
+ pub fn writer(self) -> UserSlicePtrWriter {
+ UserSlicePtrWriter(self.0, self.1)
+ }
+
+ /// Constructs both a [`UserSlicePtrReader`] and a [`UserSlicePtrWriter`].
+ pub fn reader_writer(self) -> (UserSlicePtrReader, UserSlicePtrWriter) {
+ (
+ UserSlicePtrReader(self.0, self.1),
+ UserSlicePtrWriter(self.0, self.1),
+ )
+ }
+}
+
+/// A reader for [`UserSlicePtr`].
+///
+/// Used to incrementally read from the user slice.
+pub struct UserSlicePtrReader(*mut core::ffi::c_void, usize);
+
+impl IoBufferReader for UserSlicePtrReader {
+ /// Returns the number of bytes left to be read from this.
+ ///
+ /// Note that even reading less than this number of bytes may fail.
+ fn len(&self) -> usize {
+ self.1
+ }
+
+ /// Reads raw data from the user slice into a raw kernel buffer.
+ ///
+ /// # Safety
+ ///
+ /// The output buffer must be valid.
+ unsafe fn read_raw(&mut self, out: *mut u8, len: usize) -> Result {
+ if len > self.1 || len > u32::MAX as usize {
+ return Err(EFAULT);
+ }
+ let res = unsafe { bindings::copy_from_user(out as _, self.0, len as _) };
+ if res != 0 {
+ return Err(EFAULT);
+ }
+ // Since this is not a pointer to a valid object in our program,
+ // we cannot use `add`, which has C-style rules for defined
+ // behavior.
+ self.0 = self.0.wrapping_add(len);
+ self.1 -= len;
+ Ok(())
+ }
+}
+
+/// A writer for [`UserSlicePtr`].
+///
+/// Used to incrementally write into the user slice.
+pub struct UserSlicePtrWriter(*mut core::ffi::c_void, usize);
+
+impl IoBufferWriter for UserSlicePtrWriter {
+ fn len(&self) -> usize {
+ self.1
+ }
+
+ fn clear(&mut self, mut len: usize) -> Result {
+ let mut ret = Ok(());
+ if len > self.1 {
+ ret = Err(EFAULT);
+ len = self.1;
+ }
+
+ // SAFETY: The buffer will be validated by `clear_user`. We ensure that `len` is within
+ // bounds in the check above.
+ let left = unsafe { bindings::clear_user(self.0, len as _) } as usize;
+ if left != 0 {
+ ret = Err(EFAULT);
+ len -= left;
+ }
+
+ self.0 = self.0.wrapping_add(len);
+ self.1 -= len;
+ ret
+ }
+
+ unsafe fn write_raw(&mut self, data: *const u8, len: usize) -> Result {
+ if len > self.1 || len > u32::MAX as usize {
+ return Err(EFAULT);
+ }
+ let res = unsafe { bindings::copy_to_user(self.0, data as _, len as _) };
+ if res != 0 {
+ return Err(EFAULT);
+ }
+ // Since this is not a pointer to a valid object in our program,
+ // we cannot use `add`, which has C-style rules for defined
+ // behavior.
+ self.0 = self.0.wrapping_add(len);
+ self.1 -= len;
+ Ok(())
+ }
+}
diff --git a/rust/kernel/workqueue.rs b/rust/kernel/workqueue.rs
new file mode 100644
index 000000000000..c6b89f137469
--- /dev/null
+++ b/rust/kernel/workqueue.rs
@@ -0,0 +1,512 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Work queues.
+//!
+//! C header: [`include/linux/workqueue.h`](../../../../include/linux/workqueue.h)
+
+use crate::{
+ bindings, c_str,
+ error::code::*,
+ sync::{LockClassKey, Ref, UniqueRef},
+ Opaque, Result,
+};
+use core::{fmt, ops::Deref, ptr::NonNull};
+
+/// Spawns a new work item to run in the work queue.
+///
+/// It also automatically defines a new lockdep lock class for the work item.
+#[macro_export]
+macro_rules! spawn_work_item {
+ ($queue:expr, $func:expr) => {{
+ static CLASS: $crate::sync::LockClassKey = $crate::sync::LockClassKey::new();
+ $crate::workqueue::Queue::try_spawn($queue, &CLASS, $func)
+ }};
+}
+
+/// Implements the [`WorkAdapter`] trait for a type where its [`Work`] instance is a field.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::workqueue::Work;
+///
+/// struct Example {
+/// work: Work,
+/// }
+///
+/// kernel::impl_self_work_adapter!(Example, work, |_| {});
+/// ```
+#[macro_export]
+macro_rules! impl_self_work_adapter {
+ ($work_type:ty, $field:ident, $closure:expr) => {
+ $crate::impl_work_adapter!($work_type, $work_type, $field, $closure);
+ };
+}
+
+/// Implements the [`WorkAdapter`] trait for an adapter type.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::workqueue::Work;
+///
+/// struct Example {
+/// work: Work,
+/// }
+///
+/// struct Adapter;
+///
+/// kernel::impl_work_adapter!(Adapter, Example, work, |_| {});
+/// ```
+#[macro_export]
+macro_rules! impl_work_adapter {
+ ($adapter:ty, $work_type:ty, $field:ident, $closure:expr) => {
+ // SAFETY: We use `offset_of` to ensure that the field is within the given type, and we
+ // also check its type is `Work`.
+ unsafe impl $crate::workqueue::WorkAdapter for $adapter {
+ type Target = $work_type;
+ const FIELD_OFFSET: isize = $crate::offset_of!(Self::Target, $field);
+ fn run(w: $crate::sync::Ref<Self::Target>) {
+ let closure: fn($crate::sync::Ref<Self::Target>) = $closure;
+ closure(w);
+ return;
+
+ // Checks that the type of the field is actually `Work`.
+ let tmp = core::mem::MaybeUninit::<$work_type>::uninit();
+ // SAFETY: The pointer is valid and aligned, just not initialised; `addr_of`
+ // ensures that we don't actually read from it (which would be UB) nor create an
+ // intermediate reference.
+ let _x: *const $crate::workqueue::Work =
+ unsafe { core::ptr::addr_of!((*tmp.as_ptr()).$field) };
+ }
+ }
+ };
+}
+
+/// Initialises a work item.
+///
+/// It automatically defines a new lockdep lock class for the work item.
+#[macro_export]
+macro_rules! init_work_item {
+ ($work_container:expr) => {{
+ static CLASS: $crate::sync::LockClassKey = $crate::sync::LockClassKey::new();
+ $crate::workqueue::Work::init($work_container, &CLASS)
+ }};
+}
+
+/// Initialises a work item with the given adapter.
+///
+/// It automatically defines a new lockdep lock class for the work item.
+#[macro_export]
+macro_rules! init_work_item_adapter {
+ ($adapter:ty, $work_container:expr) => {{
+ static CLASS: $crate::sync::LockClassKey = $crate::sync::LockClassKey::new();
+ $crate::workqueue::Work::init_with_adapter::<$adapter>($work_container, &CLASS)
+ }};
+}
+
+/// A kernel work queue.
+///
+/// Wraps the kernel's C `struct workqueue_struct`.
+///
+/// It allows work items to be queued to run on thread pools managed by the kernel. Several are
+/// always available, for example, the ones returned by [`system`], [`system_highpri`],
+/// [`system_long`], etc.
+///
+/// # Examples
+///
+/// The following example is the simplest way to launch a work item:
+///
+/// ```
+/// # use kernel::{spawn_work_item, workqueue};
+///
+/// # fn example() -> Result {
+/// spawn_work_item!(workqueue::system(), || pr_info!("Hello from a work item\n"))?;
+/// # Ok(())
+/// # }
+///
+/// # example().unwrap()
+/// ```
+///
+/// The following example is used to create a work item and enqueue it several times. We note that
+/// enqueuing while the work item is already queued is a no-op, so we enqueue it when it is not
+/// enqueued yet.
+///
+/// ```
+/// # use kernel::workqueue::{self, Work};
+/// use core::sync::atomic::{AtomicU32, Ordering};
+/// use kernel::sync::UniqueRef;
+///
+/// struct Example {
+/// count: AtomicU32,
+/// work: Work,
+/// }
+///
+/// kernel::impl_self_work_adapter!(Example, work, |w| {
+/// let count = w.count.fetch_add(1, Ordering::Relaxed);
+/// pr_info!("Called with count={}\n", count);
+///
+/// // Queue again if the count is less than 10.
+/// if count < 10 {
+/// workqueue::system().enqueue(w);
+/// }
+/// });
+///
+/// # fn example() -> Result {
+/// let e = UniqueRef::try_new(Example {
+/// count: AtomicU32::new(0),
+/// // SAFETY: `work` is initialised below.
+/// work: unsafe { Work::new() },
+/// })?;
+///
+/// kernel::init_work_item!(&e);
+///
+/// // Queue the first time.
+/// workqueue::system().enqueue(e.into());
+/// # Ok(())
+/// # }
+///
+/// # example().unwrap()
+/// ```
+///
+/// The following example has two different work items in the same struct, which allows it to be
+/// queued twice.
+///
+/// ```
+/// # use kernel::workqueue::{self, Work, WorkAdapter};
+/// use core::sync::atomic::{AtomicU32, Ordering};
+/// use kernel::sync::{Ref, UniqueRef};
+///
+/// struct Example {
+/// work1: Work,
+/// work2: Work,
+/// }
+///
+/// kernel::impl_self_work_adapter!(Example, work1, |_| pr_info!("First work\n"));
+///
+/// struct SecondAdapter;
+/// kernel::impl_work_adapter!(SecondAdapter, Example, work2, |_| pr_info!("Second work\n"));
+///
+/// # fn example() -> Result {
+/// let e = UniqueRef::try_new(Example {
+/// // SAFETY: `work1` is initialised below.
+/// work1: unsafe { Work::new() },
+/// // SAFETY: `work2` is initialised below.
+/// work2: unsafe { Work::new() },
+/// })?;
+///
+/// kernel::init_work_item!(&e);
+/// kernel::init_work_item_adapter!(SecondAdapter, &e);
+///
+/// let e = Ref::from(e);
+///
+/// // Enqueue the two different work items.
+/// workqueue::system().enqueue(e.clone());
+/// workqueue::system().enqueue_adapter::<SecondAdapter>(e);
+/// # Ok(())
+/// # }
+///
+/// # example().unwrap()
+/// ```
+#[repr(transparent)]
+pub struct Queue(Opaque<bindings::workqueue_struct>);
+
+// SAFETY: Kernel workqueues are usable from any thread.
+unsafe impl Sync for Queue {}
+
+impl Queue {
+ /// Tries to allocate a new work queue.
+ ///
+ /// Callers should first consider using one of the existing ones (e.g. [`system`]) before
+ /// deciding to create a new one.
+ pub fn try_new(name: fmt::Arguments<'_>) -> Result<BoxedQueue> {
+ // SAFETY: We use a format string that requires an `fmt::Arguments` pointer as the first
+ // and only argument.
+ let ptr = unsafe {
+ bindings::alloc_workqueue(
+ c_str!("%pA").as_char_ptr(),
+ 0,
+ 0,
+ &name as *const _ as *const core::ffi::c_void,
+ )
+ };
+ if ptr.is_null() {
+ return Err(ENOMEM);
+ }
+
+ // SAFETY: `ptr` was just allocated and checked above, so it non-null and valid. Plus, it
+ // isn't touched after the call below, so ownership is transferred.
+ Ok(unsafe { BoxedQueue::new(ptr) })
+ }
+
+ /// Enqueues a work item.
+ ///
+ /// Returns `true` if the work item was successfully enqueue; returns `false` if it had already
+ /// been (and continued to be) enqueued.
+ pub fn enqueue<T: WorkAdapter<Target = T>>(&self, w: Ref<T>) -> bool {
+ self.enqueue_adapter::<T>(w)
+ }
+
+ /// Enqueues a work item with an explicit adapter.
+ ///
+ /// Returns `true` if the work item was successfully enqueue; returns `false` if it had already
+ /// been (and continued to be) enqueued.
+ pub fn enqueue_adapter<A: WorkAdapter + ?Sized>(&self, w: Ref<A::Target>) -> bool {
+ let ptr = Ref::into_raw(w);
+ let field_ptr =
+ (ptr as *const u8).wrapping_offset(A::FIELD_OFFSET) as *mut bindings::work_struct;
+
+ // SAFETY: Having a shared reference to work queue guarantees that it remains valid, while
+ // the work item remains valid because we called `into_raw` and only call `from_raw` again
+ // if the object was already queued (so a previous call already guarantees it remains
+ // alive), when the work item runs, or when the work item is canceled.
+ let ret = unsafe {
+ bindings::queue_work_on(bindings::WORK_CPU_UNBOUND as _, self.0.get(), field_ptr)
+ };
+
+ if !ret {
+ // SAFETY: `ptr` comes from a previous call to `into_raw`. Additionally, given that
+ // `queue_work_on` returned `false`, we know that no-one is going to use the result of
+ // `into_raw`, so we must drop it here to avoid a reference leak.
+ unsafe { Ref::from_raw(ptr) };
+ }
+
+ ret
+ }
+
+ /// Tries to spawn the given function or closure as a work item.
+ ///
+ /// Users are encouraged to use [`spawn_work_item`] as it automatically defines the lock class
+ /// key to be used.
+ pub fn try_spawn<T: 'static + Send + Fn()>(
+ &self,
+ key: &'static LockClassKey,
+ func: T,
+ ) -> Result {
+ let w = UniqueRef::<ClosureAdapter<T>>::try_new(ClosureAdapter {
+ // SAFETY: `work` is initialised below.
+ work: unsafe { Work::new() },
+ func,
+ })?;
+ Work::init(&w, key);
+ self.enqueue(w.into());
+ Ok(())
+ }
+}
+
+struct ClosureAdapter<T: Fn() + Send> {
+ work: Work,
+ func: T,
+}
+
+// SAFETY: `ClosureAdapter::work` is of type `Work`.
+unsafe impl<T: Fn() + Send> WorkAdapter for ClosureAdapter<T> {
+ type Target = Self;
+ const FIELD_OFFSET: isize = crate::offset_of!(Self, work);
+
+ fn run(w: Ref<Self::Target>) {
+ (w.func)();
+ }
+}
+
+/// An adapter for work items.
+///
+/// For the most usual case where a type has a [`Work`] in it and is itself the adapter, it is
+/// recommended that they use the [`impl_self_work_adapter`] or [`impl_work_adapter`] macros
+/// instead of implementing the [`WorkAdapter`] manually. The great advantage is that they don't
+/// require any unsafe blocks.
+///
+/// # Safety
+///
+/// Implementers must ensure that there is a [`Work`] instance `FIELD_OFFSET` bytes from the
+/// beginning of a valid `Target` type. It is normally safe to use the [`crate::offset_of`] macro
+/// for this.
+pub unsafe trait WorkAdapter {
+ /// The type that this work adapter is meant to use.
+ type Target;
+
+ /// The offset, in bytes, from the beginning of [`Self::Target`] to the instance of [`Work`].
+ const FIELD_OFFSET: isize;
+
+ /// Runs when the work item is picked up for execution after it has been enqueued to some work
+ /// queue.
+ fn run(w: Ref<Self::Target>);
+}
+
+/// A work item.
+///
+/// Wraps the kernel's C `struct work_struct`.
+///
+/// Users must add a field of this type to a structure, then implement [`WorkAdapter`] so that it
+/// can be queued for execution in a thread pool. Examples of it being used are available in the
+/// documentation for [`Queue`].
+#[repr(transparent)]
+pub struct Work(Opaque<bindings::work_struct>);
+
+impl Work {
+ /// Creates a new instance of [`Work`].
+ ///
+ /// # Safety
+ ///
+ /// Callers must call either [`Work::init`] or [`Work::init_with_adapter`] before the work item
+ /// can be used.
+ pub unsafe fn new() -> Self {
+ Self(Opaque::uninit())
+ }
+
+ /// Initialises the work item.
+ ///
+ /// Users should prefer the [`init_work_item`] macro because it automatically defines a new
+ /// lock class key.
+ pub fn init<T: WorkAdapter<Target = T>>(obj: &UniqueRef<T>, key: &'static LockClassKey) {
+ Self::init_with_adapter::<T>(obj, key)
+ }
+
+ /// Initialises the work item with the given adapter.
+ ///
+ /// Users should prefer the [`init_work_item_adapter`] macro because it automatically defines a
+ /// new lock class key.
+ pub fn init_with_adapter<A: WorkAdapter>(
+ obj: &UniqueRef<A::Target>,
+ key: &'static LockClassKey,
+ ) {
+ let ptr = &**obj as *const _ as *const u8;
+ let field_ptr = ptr.wrapping_offset(A::FIELD_OFFSET) as *mut bindings::work_struct;
+
+ // SAFETY: `work` is valid for writes -- the `UniqueRef` instance guarantees that it has
+ // been allocated and there is only one pointer to it. Additionally, `work_func` is a valid
+ // callback for the work item.
+ unsafe {
+ bindings::__INIT_WORK_WITH_KEY(field_ptr, Some(Self::work_func::<A>), false, key.get())
+ };
+ }
+
+ /// Cancels the work item.
+ ///
+ /// It is ok for this to be called when the work is not queued.
+ pub fn cancel(&self) {
+ // SAFETY: The work is valid (we have a reference to it), and the function can be called
+ // whether the work is queued or not.
+ if unsafe { bindings::cancel_work_sync(self.0.get()) } {
+ // SAFETY: When the work was queued, a call to `into_raw` was made. We just canceled
+ // the work without it having the chance to run, so we need to explicitly destroy this
+ // reference (which would have happened in `work_func` if it did run).
+ unsafe { Ref::from_raw(&*self) };
+ }
+ }
+
+ unsafe extern "C" fn work_func<A: WorkAdapter>(work: *mut bindings::work_struct) {
+ let field_ptr = work as *const _ as *const u8;
+ let ptr = field_ptr.wrapping_offset(-A::FIELD_OFFSET) as *const A::Target;
+
+ // SAFETY: This callback is only ever used by the `init_with_adapter` method, so it is
+ // always the case that the work item is embedded in a `Work` (Self) struct.
+ let w = unsafe { Ref::from_raw(ptr) };
+ A::run(w);
+ }
+}
+
+/// A boxed owned workqueue.
+///
+/// # Invariants
+///
+/// `ptr` is owned by this instance of [`BoxedQueue`], so it's always valid.
+pub struct BoxedQueue {
+ ptr: NonNull<Queue>,
+}
+
+impl BoxedQueue {
+ /// Creates a new instance of [`BoxedQueue`].
+ ///
+ /// # Safety
+ ///
+ /// `ptr` must be non-null and valid. Additionally, ownership must be handed over to new
+ /// instance of [`BoxedQueue`].
+ unsafe fn new(ptr: *mut bindings::workqueue_struct) -> Self {
+ Self {
+ // SAFETY: We checked above that `ptr` is non-null.
+ ptr: unsafe { NonNull::new_unchecked(ptr.cast()) },
+ }
+ }
+}
+
+impl Deref for BoxedQueue {
+ type Target = Queue;
+
+ fn deref(&self) -> &Queue {
+ // SAFETY: The type invariants guarantee that `ptr` is always valid.
+ unsafe { self.ptr.as_ref() }
+ }
+}
+
+impl Drop for BoxedQueue {
+ fn drop(&mut self) {
+ // SAFETY: The type invariants guarantee that `ptr` is always valid.
+ unsafe { bindings::destroy_workqueue(self.ptr.as_ref().0.get()) };
+ }
+}
+
+/// Returns the system work queue (`system_wq`).
+///
+/// It is the one used by schedule\[_delayed\]_work\[_on\](). Multi-CPU multi-threaded. There are
+/// users which expect relatively short queue flush time.
+///
+/// Callers shouldn't queue work items which can run for too long.
+pub fn system() -> &'static Queue {
+ // SAFETY: `system_wq` is a C global, always available.
+ unsafe { &*bindings::system_wq.cast() }
+}
+
+/// Returns the system high-priority work queue (`system_highpri_wq`).
+///
+/// It is similar to the one returned by [`system`] but for work items which require higher
+/// scheduling priority.
+pub fn system_highpri() -> &'static Queue {
+ // SAFETY: `system_highpri_wq` is a C global, always available.
+ unsafe { &*bindings::system_highpri_wq.cast() }
+}
+
+/// Returns the system work queue for potentially long-running work items (`system_long_wq`).
+///
+/// It is similar to the one returned by [`system`] but may host long running work items. Queue
+/// flushing might take relatively long.
+pub fn system_long() -> &'static Queue {
+ // SAFETY: `system_long_wq` is a C global, always available.
+ unsafe { &*bindings::system_long_wq.cast() }
+}
+
+/// Returns the system unbound work queue (`system_unbound_wq`).
+///
+/// Workers are not bound to any specific CPU, not concurrency managed, and all queued work items
+/// are executed immediately as long as `max_active` limit is not reached and resources are
+/// available.
+pub fn system_unbound() -> &'static Queue {
+ // SAFETY: `system_unbound_wq` is a C global, always available.
+ unsafe { &*bindings::system_unbound_wq.cast() }
+}
+
+/// Returns the system freezable work queue (`system_freezable_wq`).
+///
+/// It is equivalent to the one returned by [`system`] except that it's freezable.
+pub fn system_freezable() -> &'static Queue {
+ // SAFETY: `system_freezable_wq` is a C global, always available.
+ unsafe { &*bindings::system_freezable_wq.cast() }
+}
+
+/// Returns the system power-efficient work queue (`system_power_efficient_wq`).
+///
+/// It is inclined towards saving power and is converted to "unbound" variants if the
+/// `workqueue.power_efficient` kernel parameter is specified; otherwise, it is similar to the one
+/// returned by [`system`].
+pub fn system_power_efficient() -> &'static Queue {
+ // SAFETY: `system_power_efficient_wq` is a C global, always available.
+ unsafe { &*bindings::system_power_efficient_wq.cast() }
+}
+
+/// Returns the system freezable power-efficient work queue (`system_freezable_power_efficient_wq`).
+///
+/// It is similar to the one returned by [`system_power_efficient`] except that is freezable.
+pub fn system_freezable_power_efficient() -> &'static Queue {
+ // SAFETY: `system_freezable_power_efficient_wq` is a C global, always available.
+ unsafe { &*bindings::system_freezable_power_efficient_wq.cast() }
+}
--
2.37.1

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