[PATCH 02/10] x86/fpu: Clean up and rename variables in signal frame handling
From: Andrei Vagin
Date: Mon Jun 15 2026 - 15:38:28 EST
Clean up signal frame handling code by renaming several variables for
clarity and consistency, and moving masking logic closer to its usage.
- Rename 'fxbuf' to 'buf_fx' in check_xstate_in_sigframe() for consistency.
- Rename label 'setfx' to 'err_setfx' in check_xstate_in_sigframe() to
indicate it is an error path.
- In __restore_fpregs_from_user(), rename 'ufeatures' to 'task_xfeatures'
and 'xrestore' to 'xrestore_mask'.
- Move the masking logic 'xrestore_mask &= task_xfeatures' from
restore_fpregs_from_user() into __restore_fpregs_from_user().
- Rename 'xrestore' to 'xrestore_mask' in restore_fpregs_from_user() to
match the name in __restore_fpregs_from_user() and __fpu_restore_sig().
- In __fpu_restore_sig(), rename 'buf' to 'buf_f' to distinguish it from
'buf_fx', and 'user_xfeatures' to 'xrestore_mask'.
No functional changes.
Suggested-by: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Andrei Vagin <avagin@xxxxxxxxxx>
---
arch/x86/kernel/fpu/signal.c | 40 ++++++++++++++++++------------------
1 file changed, 20 insertions(+), 20 deletions(-)
diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c
index 20b638c507ca..42c3d78bd849 100644
--- a/arch/x86/kernel/fpu/signal.c
+++ b/arch/x86/kernel/fpu/signal.c
@@ -24,15 +24,15 @@
* Check for the presence of extended state information in the
* user fpstate pointer in the sigcontext.
*/
-static inline bool check_xstate_in_sigframe(struct fxregs_state __user *fxbuf,
+static inline bool check_xstate_in_sigframe(struct fxregs_state __user *buf_fx,
struct _fpx_sw_bytes *fx_sw)
{
int min_xstate_size = sizeof(struct fxregs_state) +
sizeof(struct xstate_header);
- void __user *fpstate = fxbuf;
+ void __user *fpstate = buf_fx;
unsigned int magic2;
- if (__copy_from_user(fx_sw, &fxbuf->sw_reserved[0], sizeof(*fx_sw)))
+ if (__copy_from_user(fx_sw, &buf_fx->sw_reserved[0], sizeof(*fx_sw)))
return false;
/* Check for the first magic field and other error scenarios. */
@@ -40,7 +40,7 @@ static inline bool check_xstate_in_sigframe(struct fxregs_state __user *fxbuf,
fx_sw->xstate_size < min_xstate_size ||
fx_sw->xstate_size > x86_task_fpu(current)->fpstate->user_size ||
fx_sw->xstate_size > fx_sw->extended_size)
- goto setfx;
+ goto err_setfx;
/*
* Check for the presence of second magic word at the end of memory
@@ -53,7 +53,7 @@ static inline bool check_xstate_in_sigframe(struct fxregs_state __user *fxbuf,
if (likely(magic2 == FP_XSTATE_MAGIC2))
return true;
-setfx:
+err_setfx:
trace_x86_fpu_xstate_check_failed(x86_task_fpu(current));
/* Set the parameters for fx only state */
@@ -240,15 +240,17 @@ bool copy_fpstate_to_sigframe(void __user *buf, void __user *buf_fx, int size, u
return true;
}
-static int __restore_fpregs_from_user(void __user *buf, u64 ufeatures,
- u64 xrestore, bool fx_only)
+static int __restore_fpregs_from_user(void __user *buf, u64 task_xfeatures,
+ u64 xrestore_mask, bool fx_only)
{
if (use_xsave()) {
- u64 init_bv = ufeatures & ~xrestore;
+ u64 init_bv = task_xfeatures & ~xrestore_mask;
int ret;
+ /* Restore enabled features only. */
+ xrestore_mask &= task_xfeatures;
if (likely(!fx_only))
- ret = xrstor_from_user_sigframe(buf, xrestore);
+ ret = xrstor_from_user_sigframe(buf, xrestore_mask);
else
ret = fxrstor_from_user_sigframe(buf);
@@ -266,20 +268,18 @@ static int __restore_fpregs_from_user(void __user *buf, u64 ufeatures,
* Attempt to restore the FPU registers directly from user memory.
* Pagefaults are handled and any errors returned are fatal.
*/
-static bool restore_fpregs_from_user(void __user *buf, u64 xrestore, bool fx_only)
+static bool restore_fpregs_from_user(void __user *buf, u64 xrestore_mask, bool fx_only)
{
struct fpu *fpu = x86_task_fpu(current);
int ret;
- /* Restore enabled features only. */
- xrestore &= fpu->fpstate->user_xfeatures;
retry:
fpregs_lock();
/* Ensure that XFD is up to date */
xfd_update_state(fpu->fpstate);
pagefault_disable();
ret = __restore_fpregs_from_user(buf, fpu->fpstate->user_xfeatures,
- xrestore, fx_only);
+ xrestore_mask, fx_only);
pagefault_enable();
if (unlikely(ret)) {
@@ -324,7 +324,7 @@ static bool restore_fpregs_from_user(void __user *buf, u64 xrestore, bool fx_onl
return true;
}
-static bool __fpu_restore_sig(void __user *buf, void __user *buf_fx,
+static bool __fpu_restore_sig(void __user *buf_f, void __user *buf_fx,
bool ia32_fxstate)
{
struct task_struct *tsk = current;
@@ -332,7 +332,7 @@ static bool __fpu_restore_sig(void __user *buf, void __user *buf_fx,
struct user_i387_ia32_struct env;
bool success, fx_only = false;
union fpregs_state *fpregs;
- u64 user_xfeatures = 0;
+ u64 xrestore_mask = 0;
if (use_xsave()) {
struct _fpx_sw_bytes fx_sw_user;
@@ -341,14 +341,14 @@ static bool __fpu_restore_sig(void __user *buf, void __user *buf_fx,
return false;
fx_only = !fx_sw_user.magic1;
- user_xfeatures = fx_sw_user.xfeatures;
+ xrestore_mask = fx_sw_user.xfeatures;
} else {
- user_xfeatures = XFEATURE_MASK_FPSSE;
+ xrestore_mask = XFEATURE_MASK_FPSSE;
}
if (likely(!ia32_fxstate)) {
/* Restore the FPU registers directly from user memory. */
- return restore_fpregs_from_user(buf_fx, user_xfeatures, fx_only);
+ return restore_fpregs_from_user(buf_fx, xrestore_mask, fx_only);
}
/*
@@ -356,7 +356,7 @@ static bool __fpu_restore_sig(void __user *buf, void __user *buf_fx,
* to be ignored for histerical raisins. The legacy state is folded
* in once the larger state has been copied.
*/
- if (__copy_from_user(&env, buf, sizeof(env)))
+ if (__copy_from_user(&env, buf_f, sizeof(env)))
return false;
/*
@@ -420,7 +420,7 @@ static bool __fpu_restore_sig(void __user *buf, void __user *buf_fx,
*
* Preserve supervisor states!
*/
- u64 mask = user_xfeatures | xfeatures_mask_supervisor();
+ u64 mask = xrestore_mask | xfeatures_mask_supervisor();
fpregs->xsave.header.xfeatures &= mask;
success = !os_xrstor_safe(fpu->fpstate,
--
2.54.0.1189.g8c84645362-goog