Re: [PATCH RESEND v8 07/16] mm/execmem, arch: convert simple overrides of module_alloc to execmem

From: Google
Date: Tue May 07 2024 - 20:09:25 EST

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In reply to: Mike Rapoport: "[PATCH RESEND v8 07/16] mm/execmem, arch: convert simple overrides of module_alloc to execmem"
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On Sun, 5 May 2024 19:06:19 +0300
Mike Rapoport <rppt@xxxxxxxxxx> wrote:

> From: "Mike Rapoport (IBM)" <rppt@xxxxxxxxxx>
>
> Several architectures override module_alloc() only to define address
> range for code allocations different than VMALLOC address space.
>
> Provide a generic implementation in execmem that uses the parameters for
> address space ranges, required alignment and page protections provided
> by architectures.
>
> The architectures must fill execmem_info structure and implement
> execmem_arch_setup() that returns a pointer to that structure. This way the
> execmem initialization won't be called from every architecture, but rather
> from a central place, namely a core_initcall() in execmem.
>
> The execmem provides execmem_alloc() API that wraps __vmalloc_node_range()
> with the parameters defined by the architectures. If an architecture does
> not implement execmem_arch_setup(), execmem_alloc() will fall back to
> module_alloc().
>

Looks good to me.

Reviewed-by: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>

Thanks,

> Signed-off-by: Mike Rapoport (IBM) <rppt@xxxxxxxxxx>
> Acked-by: Song Liu <song@xxxxxxxxxx>
> ---
> arch/loongarch/kernel/module.c | 19 ++++++++--
> arch/mips/kernel/module.c | 20 ++++++++--
> arch/nios2/kernel/module.c | 21 ++++++++---
> arch/parisc/kernel/module.c | 24 ++++++++----
> arch/riscv/kernel/module.c | 24 ++++++++----
> arch/sparc/kernel/module.c | 20 ++++++++--
> include/linux/execmem.h | 47 ++++++++++++++++++++++++
> mm/execmem.c | 67 ++++++++++++++++++++++++++++++++--
> mm/mm_init.c | 2 +
> 9 files changed, 210 insertions(+), 34 deletions(-)
>
> diff --git a/arch/loongarch/kernel/module.c b/arch/loongarch/kernel/module.c
> index c7d0338d12c1..ca6dd7ea1610 100644
> --- a/arch/loongarch/kernel/module.c
> +++ b/arch/loongarch/kernel/module.c
> @@ -18,6 +18,7 @@
> #include <linux/ftrace.h>
> #include <linux/string.h>
> #include <linux/kernel.h>
> +#include <linux/execmem.h>
> #include <asm/alternative.h>
> #include <asm/inst.h>
> #include <asm/unwind.h>
> @@ -490,10 +491,22 @@ int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
> return 0;
> }
>
> -void *module_alloc(unsigned long size)
> +static struct execmem_info execmem_info __ro_after_init;
> +
> +struct execmem_info __init *execmem_arch_setup(void)
> {
> - return __vmalloc_node_range(size, 1, MODULES_VADDR, MODULES_END,
> - GFP_KERNEL, PAGE_KERNEL, 0, NUMA_NO_NODE, __builtin_return_address(0));
> + execmem_info = (struct execmem_info){
> + .ranges = {
> + [EXECMEM_DEFAULT] = {
> + .start = MODULES_VADDR,
> + .end = MODULES_END,
> + .pgprot = PAGE_KERNEL,
> + .alignment = 1,
> + },
> + },
> + };
> +
> + return &execmem_info;
> }
>
> static void module_init_ftrace_plt(const Elf_Ehdr *hdr,
> diff --git a/arch/mips/kernel/module.c b/arch/mips/kernel/module.c
> index 9a6c96014904..59225a3cf918 100644
> --- a/arch/mips/kernel/module.c
> +++ b/arch/mips/kernel/module.c
> @@ -20,6 +20,7 @@
> #include <linux/kernel.h>
> #include <linux/spinlock.h>
> #include <linux/jump_label.h>
> +#include <linux/execmem.h>
> #include <asm/jump_label.h>
>
> struct mips_hi16 {
> @@ -32,11 +33,22 @@ static LIST_HEAD(dbe_list);
> static DEFINE_SPINLOCK(dbe_lock);
>
> #ifdef MODULES_VADDR
> -void *module_alloc(unsigned long size)
> +static struct execmem_info execmem_info __ro_after_init;
> +
> +struct execmem_info __init *execmem_arch_setup(void)
> {
> - return __vmalloc_node_range(size, 1, MODULES_VADDR, MODULES_END,
> - GFP_KERNEL, PAGE_KERNEL, 0, NUMA_NO_NODE,
> - __builtin_return_address(0));
> + execmem_info = (struct execmem_info){
> + .ranges = {
> + [EXECMEM_DEFAULT] = {
> + .start = MODULES_VADDR,
> + .end = MODULES_END,
> + .pgprot = PAGE_KERNEL,
> + .alignment = 1,
> + },
> + },
> + };
> +
> + return &execmem_info;
> }
> #endif
>
> diff --git a/arch/nios2/kernel/module.c b/arch/nios2/kernel/module.c
> index 9c97b7513853..0d1ee86631fc 100644
> --- a/arch/nios2/kernel/module.c
> +++ b/arch/nios2/kernel/module.c
> @@ -18,15 +18,26 @@
> #include <linux/fs.h>
> #include <linux/string.h>
> #include <linux/kernel.h>
> +#include <linux/execmem.h>
>
> #include <asm/cacheflush.h>
>
> -void *module_alloc(unsigned long size)
> +static struct execmem_info execmem_info __ro_after_init;
> +
> +struct execmem_info __init *execmem_arch_setup(void)
> {
> - return __vmalloc_node_range(size, 1, MODULES_VADDR, MODULES_END,
> - GFP_KERNEL, PAGE_KERNEL_EXEC,
> - VM_FLUSH_RESET_PERMS, NUMA_NO_NODE,
> - __builtin_return_address(0));
> + execmem_info = (struct execmem_info){
> + .ranges = {
> + [EXECMEM_DEFAULT] = {
> + .start = MODULES_VADDR,
> + .end = MODULES_END,
> + .pgprot = PAGE_KERNEL_EXEC,
> + .alignment = 1,
> + },
> + },
> + };
> +
> + return &execmem_info;
> }
>
> int apply_relocate_add(Elf32_Shdr *sechdrs, const char *strtab,
> diff --git a/arch/parisc/kernel/module.c b/arch/parisc/kernel/module.c
> index d214bbe3c2af..bdfa85e10c1b 100644
> --- a/arch/parisc/kernel/module.c
> +++ b/arch/parisc/kernel/module.c
> @@ -49,6 +49,7 @@
> #include <linux/bug.h>
> #include <linux/mm.h>
> #include <linux/slab.h>
> +#include <linux/execmem.h>
>
> #include <asm/unwind.h>
> #include <asm/sections.h>
> @@ -173,15 +174,22 @@ static inline int reassemble_22(int as22)
> ((as22 & 0x0003ff) << 3));
> }
>
> -void *module_alloc(unsigned long size)
> +static struct execmem_info execmem_info __ro_after_init;
> +
> +struct execmem_info __init *execmem_arch_setup(void)
> {
> - /* using RWX means less protection for modules, but it's
> - * easier than trying to map the text, data, init_text and
> - * init_data correctly */
> - return __vmalloc_node_range(size, 1, VMALLOC_START, VMALLOC_END,
> - GFP_KERNEL,
> - PAGE_KERNEL_RWX, 0, NUMA_NO_NODE,
> - __builtin_return_address(0));
> + execmem_info = (struct execmem_info){
> + .ranges = {
> + [EXECMEM_DEFAULT] = {
> + .start = VMALLOC_START,
> + .end = VMALLOC_END,
> + .pgprot = PAGE_KERNEL_RWX,
> + .alignment = 1,
> + },
> + },
> + };
> +
> + return &execmem_info;
> }
>
> #ifndef CONFIG_64BIT
> diff --git a/arch/riscv/kernel/module.c b/arch/riscv/kernel/module.c
> index 5e5a82644451..182904127ba0 100644
> --- a/arch/riscv/kernel/module.c
> +++ b/arch/riscv/kernel/module.c
> @@ -14,6 +14,7 @@
> #include <linux/vmalloc.h>
> #include <linux/sizes.h>
> #include <linux/pgtable.h>
> +#include <linux/execmem.h>
> #include <asm/alternative.h>
> #include <asm/sections.h>
>
> @@ -906,13 +907,22 @@ int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
> }
>
> #if defined(CONFIG_MMU) && defined(CONFIG_64BIT)
> -void *module_alloc(unsigned long size)
> -{
> - return __vmalloc_node_range(size, 1, MODULES_VADDR,
> - MODULES_END, GFP_KERNEL,
> - PAGE_KERNEL, VM_FLUSH_RESET_PERMS,
> - NUMA_NO_NODE,
> - __builtin_return_address(0));
> +static struct execmem_info execmem_info __ro_after_init;
> +
> +struct execmem_info __init *execmem_arch_setup(void)
> +{
> + execmem_info = (struct execmem_info){
> + .ranges = {
> + [EXECMEM_DEFAULT] = {
> + .start = MODULES_VADDR,
> + .end = MODULES_END,
> + .pgprot = PAGE_KERNEL,
> + .alignment = 1,
> + },
> + },
> + };
> +
> + return &execmem_info;
> }
> #endif
>
> diff --git a/arch/sparc/kernel/module.c b/arch/sparc/kernel/module.c
> index d37adb2a0b54..8b7ee45defc3 100644
> --- a/arch/sparc/kernel/module.c
> +++ b/arch/sparc/kernel/module.c
> @@ -14,6 +14,7 @@
> #include <linux/string.h>
> #include <linux/ctype.h>
> #include <linux/mm.h>
> +#include <linux/execmem.h>
>
> #include <asm/processor.h>
> #include <asm/spitfire.h>
> @@ -21,11 +22,22 @@
>
> #include "entry.h"
>
> -void *module_alloc(unsigned long size)
> +static struct execmem_info execmem_info __ro_after_init;
> +
> +struct execmem_info __init *execmem_arch_setup(void)
> {
> - return __vmalloc_node_range(size, 1, MODULES_VADDR, MODULES_END,
> - GFP_KERNEL, PAGE_KERNEL, 0, NUMA_NO_NODE,
> - __builtin_return_address(0));
> + execmem_info = (struct execmem_info){
> + .ranges = {
> + [EXECMEM_DEFAULT] = {
> + .start = MODULES_VADDR,
> + .end = MODULES_END,
> + .pgprot = PAGE_KERNEL,
> + .alignment = 1,
> + },
> + },
> + };
> +
> + return &execmem_info;
> }
>
> /* Make generic code ignore STT_REGISTER dummy undefined symbols. */
> diff --git a/include/linux/execmem.h b/include/linux/execmem.h
> index 8eebc8ef66e7..96fc59258467 100644
> --- a/include/linux/execmem.h
> +++ b/include/linux/execmem.h
> @@ -33,6 +33,47 @@ enum execmem_type {
> EXECMEM_TYPE_MAX,
> };
>
> +/**
> + * struct execmem_range - definition of an address space suitable for code and
> + * related data allocations
> + * @start: address space start
> + * @end: address space end (inclusive)
> + * @pgprot: permissions for memory in this address space
> + * @alignment: alignment required for text allocations
> + */
> +struct execmem_range {
> + unsigned long start;
> + unsigned long end;
> + pgprot_t pgprot;
> + unsigned int alignment;
> +};
> +
> +/**
> + * struct execmem_info - architecture parameters for code allocations
> + * @ranges: array of parameter sets defining architecture specific
> + * parameters for executable memory allocations. The ranges that are not
> + * explicitly initialized by an architecture use parameters defined for
> + * @EXECMEM_DEFAULT.
> + */
> +struct execmem_info {
> + struct execmem_range ranges[EXECMEM_TYPE_MAX];
> +};
> +
> +/**
> + * execmem_arch_setup - define parameters for allocations of executable memory
> + *
> + * A hook for architectures to define parameters for allocations of
> + * executable memory. These parameters should be filled into the
> + * @execmem_info structure.
> + *
> + * For architectures that do not implement this method a default set of
> + * parameters will be used
> + *
> + * Return: a structure defining architecture parameters and restrictions
> + * for allocations of executable memory
> + */
> +struct execmem_info *execmem_arch_setup(void);
> +
> /**
> * execmem_alloc - allocate executable memory
> * @type: type of the allocation
> @@ -54,4 +95,10 @@ void *execmem_alloc(enum execmem_type type, size_t size);
> */
> void execmem_free(void *ptr);
>
> +#ifdef CONFIG_EXECMEM
> +void execmem_init(void);
> +#else
> +static inline void execmem_init(void) {}
> +#endif
> +
> #endif /* _LINUX_EXECMEM_ALLOC_H */
> diff --git a/mm/execmem.c b/mm/execmem.c
> index 480adc69b20d..80e61c1e7319 100644
> --- a/mm/execmem.c
> +++ b/mm/execmem.c
> @@ -11,14 +11,30 @@
> #include <linux/execmem.h>
> #include <linux/moduleloader.h>
>
> -static void *__execmem_alloc(size_t size)
> +static struct execmem_info *execmem_info __ro_after_init;
> +
> +static void *__execmem_alloc(struct execmem_range *range, size_t size)
> {
> - return module_alloc(size);
> + unsigned long start = range->start;
> + unsigned long end = range->end;
> + unsigned int align = range->alignment;
> + pgprot_t pgprot = range->pgprot;
> +
> + return __vmalloc_node_range(size, align, start, end,
> + GFP_KERNEL, pgprot, VM_FLUSH_RESET_PERMS,
> + NUMA_NO_NODE, __builtin_return_address(0));
> }
>
> void *execmem_alloc(enum execmem_type type, size_t size)
> {
> - return __execmem_alloc(size);
> + struct execmem_range *range;
> +
> + if (!execmem_info)
> + return module_alloc(size);
> +
> + range = &execmem_info->ranges[type];
> +
> + return __execmem_alloc(range, size);
> }
>
> void execmem_free(void *ptr)
> @@ -30,3 +46,48 @@ void execmem_free(void *ptr)
> WARN_ON(in_interrupt());
> vfree(ptr);
> }
> +
> +static bool execmem_validate(struct execmem_info *info)
> +{
> + struct execmem_range *r = &info->ranges[EXECMEM_DEFAULT];
> +
> + if (!r->alignment || !r->start || !r->end || !pgprot_val(r->pgprot)) {
> + pr_crit("Invalid parameters for execmem allocator, module loading will fail");
> + return false;
> + }
> +
> + return true;
> +}
> +
> +static void execmem_init_missing(struct execmem_info *info)
> +{
> + struct execmem_range *default_range = &info->ranges[EXECMEM_DEFAULT];
> +
> + for (int i = EXECMEM_DEFAULT + 1; i < EXECMEM_TYPE_MAX; i++) {
> + struct execmem_range *r = &info->ranges[i];
> +
> + if (!r->start) {
> + r->pgprot = default_range->pgprot;
> + r->alignment = default_range->alignment;
> + r->start = default_range->start;
> + r->end = default_range->end;
> + }
> + }
> +}
> +
> +struct execmem_info * __weak execmem_arch_setup(void)
> +{
> + return NULL;
> +}
> +
> +void __init execmem_init(void)
> +{
> + struct execmem_info *info = execmem_arch_setup();
> +
> + if (!info || !execmem_validate(info))
> + return;
> +
> + execmem_init_missing(info);
> +
> + execmem_info = info;
> +}
> diff --git a/mm/mm_init.c b/mm/mm_init.c
> index 549e76af8f82..b6a1fcf6e13a 100644
> --- a/mm/mm_init.c
> +++ b/mm/mm_init.c
> @@ -27,6 +27,7 @@
> #include <linux/swap.h>
> #include <linux/cma.h>
> #include <linux/crash_dump.h>
> +#include <linux/execmem.h>
> #include "internal.h"
> #include "slab.h"
> #include "shuffle.h"
> @@ -2793,4 +2794,5 @@ void __init mm_core_init(void)
> pti_init();
> kmsan_init_runtime();
> mm_cache_init();
> + execmem_init();
> }
> --
> 2.43.0
>

--
Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>

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