[patch V2.1 20/20] x86/fpu/signal: Change return code of restore_fpregs_from_user() to boolean

From: Thomas Gleixner
Date: Tue Sep 07 2021 - 16:25:52 EST


__fpu_sig_restore() only needs information about success or fail and no
real error code.

This cleans up the confusing conversion of the trap number, which is
returned by the *RSTOR() exception fixups, to an error code.

Suggested-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
arch/x86/kernel/fpu/signal.c | 17 ++++++++---------
1 file changed, 8 insertions(+), 9 deletions(-)

--- a/arch/x86/kernel/fpu/signal.c
+++ b/arch/x86/kernel/fpu/signal.c
@@ -255,8 +255,8 @@ static int __restore_fpregs_from_user(vo
* Attempt to restore the FPU registers directly from user memory.
* Pagefaults are handled and any errors returned are fatal.
*/
-static int restore_fpregs_from_user(void __user *buf, u64 xrestore,
- bool fx_only, unsigned int size)
+static bool restore_fpregs_from_user(void __user *buf, u64 xrestore,
+ bool fx_only, unsigned int size)
{
struct fpu *fpu = &current->thread.fpu;
int ret;
@@ -285,12 +285,11 @@ static int restore_fpregs_from_user(void

/* Try to handle #PF, but anything else is fatal. */
if (ret != X86_TRAP_PF)
- return -EINVAL;
+ return false;

- ret = fault_in_pages_readable(buf, size);
- if (!ret)
+ if (!fault_in_pages_readable(buf, size))
goto retry;
- return ret;
+ return false;
}

/*
@@ -307,7 +306,7 @@ static int restore_fpregs_from_user(void

fpregs_mark_activate();
fpregs_unlock();
- return 0;
+ return true;
}

static bool __fpu_restore_sig(void __user *buf, void __user *buf_fx,
@@ -342,8 +341,8 @@ static bool __fpu_restore_sig(void __use
* faults. If it does, fall back to the slow path below, going
* through the kernel buffer with the enabled pagefault handler.
*/
- return !restore_fpregs_from_user(buf_fx, user_xfeatures, fx_only,
- state_size);
+ return restore_fpregs_from_user(buf_fx, user_xfeatures, fx_only,
+ state_size);
}

/*