[patch 04/10] x86/fpu/signal: Change return type of copy_fpstate_to_sigframe() to boolean

From: Thomas Gleixner
Date: Mon Aug 30 2021 - 12:27:36 EST


None of the call sites cares about the actual return code. Change the
return type to boolean and return 'true' on success.

Suggested-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
arch/x86/ia32/ia32_signal.c | 4 ++--
arch/x86/include/asm/fpu/internal.h | 2 +-
arch/x86/kernel/fpu/signal.c | 20 ++++++++++----------
arch/x86/kernel/signal.c | 4 +---
4 files changed, 14 insertions(+), 16 deletions(-)

--- a/arch/x86/ia32/ia32_signal.c
+++ b/arch/x86/ia32/ia32_signal.c
@@ -220,8 +220,8 @@ static void __user *get_sigframe(struct

sp = fpu__alloc_mathframe(sp, 1, &fx_aligned, &math_size);
*fpstate = (struct _fpstate_32 __user *) sp;
- if (copy_fpstate_to_sigframe(*fpstate, (void __user *)fx_aligned,
- math_size) < 0)
+ if (!copy_fpstate_to_sigframe(*fpstate, (void __user *)fx_aligned,
+ math_size))
return (void __user *) -1L;

sp -= frame_size;
--- a/arch/x86/include/asm/fpu/internal.h
+++ b/arch/x86/include/asm/fpu/internal.h
@@ -391,7 +391,7 @@ static inline void restore_fpregs_from_f
__restore_fpregs_from_fpstate(fpstate, xfeatures_mask_fpstate());
}

-extern int copy_fpstate_to_sigframe(void __user *buf, void __user *fp, int size);
+extern bool copy_fpstate_to_sigframe(void __user *buf, void __user *fp, int size);

/*
* FPU context switch related helper methods:
--- a/arch/x86/kernel/fpu/signal.c
+++ b/arch/x86/kernel/fpu/signal.c
@@ -165,7 +165,7 @@ static inline int copy_fpregs_to_sigfram
* For [f]xsave state, update the SW reserved fields in the [f]xsave frame
* indicating the absence/presence of the extended state to the user.
*/
-int copy_fpstate_to_sigframe(void __user *buf, void __user *buf_fx, int size)
+bool copy_fpstate_to_sigframe(void __user *buf, void __user *buf_fx, int size)
{
struct task_struct *tsk = current;
int ia32_fxstate = (buf != buf_fx);
@@ -176,13 +176,14 @@ int copy_fpstate_to_sigframe(void __user

if (!static_cpu_has(X86_FEATURE_FPU)) {
struct user_i387_ia32_struct fp;
+
fpregs_soft_get(current, NULL, (struct membuf){.p = &fp,
.left = sizeof(fp)});
- return copy_to_user(buf, &fp, sizeof(fp)) ? -EFAULT : 0;
+ return !copy_to_user(buf, &fp, sizeof(fp));
}

if (!access_ok(buf, size))
- return -EACCES;
+ return false;

if (use_xsave()) {
struct xregs_state __user *xbuf = buf_fx;
@@ -191,9 +192,8 @@ int copy_fpstate_to_sigframe(void __user
* Clear the xsave header first, so that reserved fields are
* initialized to zero.
*/
- ret = __clear_user(&xbuf->header, sizeof(xbuf->header));
- if (unlikely(ret))
- return ret;
+ if (__clear_user(&xbuf->header, sizeof(xbuf->header)))
+ return false;
}
retry:
/*
@@ -215,17 +215,17 @@ int copy_fpstate_to_sigframe(void __user
if (!__clear_user(buf_fx, fpu_user_xstate_size) &&
ret == -X86_TRAP_PF)
goto retry;
- return -1;
+ return false;
}

/* Save the fsave header for the 32-bit frames. */
if ((ia32_fxstate || !use_fxsr()) && save_fsave_header(tsk, buf))
- return -1;
+ return false;

if (use_fxsr() && save_xstate_epilog(buf_fx, ia32_fxstate))
- return -1;
+ return false;

- return 0;
+ return true;
}

static int __restore_fpregs_from_user(void __user *buf, u64 xrestore,
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -244,7 +244,6 @@ get_sigframe(struct k_sigaction *ka, str
unsigned long math_size = 0;
unsigned long sp = regs->sp;
unsigned long buf_fx = 0;
- int ret;

/* redzone */
if (IS_ENABLED(CONFIG_X86_64))
@@ -292,8 +291,7 @@ get_sigframe(struct k_sigaction *ka, str
}

/* save i387 and extended state */
- ret = copy_fpstate_to_sigframe(*fpstate, (void __user *)buf_fx, math_size);
- if (ret < 0)
+ if (!copy_fpstate_to_sigframe(*fpstate, (void __user *)buf_fx, math_size))
return (void __user *)-1L;

return (void __user *)sp;