[patch 08/21] x86/fpu/signal: Convert to fpstate

Thomas Gleixner
2021-10-13T14:55:53Z

Convert signal related code to the new register storage mechanism in
preparation for dynamically sized buffers.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
arch/x86/kernel/fpu/signal.c | 30 ++++++++++++++++--------------
1 file changed, 16 insertions(+), 14 deletions(-)

--- a/arch/x86/kernel/fpu/signal.c
+++ b/arch/x86/kernel/fpu/signal.c
@@ -72,13 +72,13 @@ static inline bool check_xstate_in_sigfr
static inline bool save_fsave_header(struct task_struct *tsk, void __user *buf)
{
if (use_fxsr()) {
- struct xregs_state *xsave = &tsk->thread.fpu.state.xsave;
+ struct xregs_state *xsave = &tsk->thread.fpu.fpstate->regs.xsave;
struct user_i387_ia32_struct env;
struct _fpstate_32 __user *fp = buf;

fpregs_lock();
if (!test_thread_flag(TIF_NEED_FPU_LOAD))
- fxsave(&tsk->thread.fpu.state.fxsave);
+ fxsave(&tsk->thread.fpu.fpstate->regs.fxsave);
fpregs_unlock();

convert_from_fxsr(&env, tsk);
@@ -303,7 +303,7 @@ static bool restore_fpregs_from_user(voi
* been restored from a user buffer directly.
*/
if (test_thread_flag(TIF_NEED_FPU_LOAD) && xfeatures_mask_supervisor())
- os_xrstor(&fpu->state.xsave, xfeatures_mask_supervisor());
+ os_xrstor(&fpu->fpstate->regs.xsave, xfeatures_mask_supervisor());

fpregs_mark_activate();
fpregs_unlock();
@@ -317,6 +317,7 @@ static bool __fpu_restore_sig(void __use
struct task_struct *tsk = current;
struct fpu *fpu = &tsk->thread.fpu;
struct user_i387_ia32_struct env;
+ union fpregs_state *fpregs;
u64 user_xfeatures = 0;
bool fx_only = false;
bool success;
@@ -349,6 +350,7 @@ static bool __fpu_restore_sig(void __use
if (__copy_from_user(&env, buf, sizeof(env)))
return false;

+ fpregs = &fpu->fpstate->regs;
/*
* By setting TIF_NEED_FPU_LOAD it is ensured that our xstate is
* not modified on context switch and that the xstate is considered
@@ -366,7 +368,7 @@ static bool __fpu_restore_sig(void __use
* the right place in memory. It's ia32 mode. Shrug.
*/
if (xfeatures_mask_supervisor())
- os_xsave(&fpu->state.xsave);
+ os_xsave(&fpregs->xsave);
set_thread_flag(TIF_NEED_FPU_LOAD);
}
__fpu_invalidate_fpregs_state(fpu);
@@ -374,29 +376,29 @@ static bool __fpu_restore_sig(void __use
fpregs_unlock();

if (use_xsave() && !fx_only) {
- if (copy_sigframe_from_user_to_xstate(&fpu->state.xsave, buf_fx))
+ if (copy_sigframe_from_user_to_xstate(&fpregs->xsave, buf_fx))
return false;
} else {
- if (__copy_from_user(&fpu->state.fxsave, buf_fx,
- sizeof(fpu->state.fxsave)))
+ if (__copy_from_user(&fpregs->fxsave, buf_fx,
+ sizeof(fpregs->fxsave)))
return false;

if (IS_ENABLED(CONFIG_X86_64)) {
/* Reject invalid MXCSR values. */
- if (fpu->state.fxsave.mxcsr & ~mxcsr_feature_mask)
+ if (fpregs->fxsave.mxcsr & ~mxcsr_feature_mask)
return false;
} else {
/* Mask invalid bits out for historical reasons (broken hardware). */
- fpu->state.fxsave.mxcsr &= ~mxcsr_feature_mask;
+ fpregs->fxsave.mxcsr &= ~mxcsr_feature_mask;
}

/* Enforce XFEATURE_MASK_FPSSE when XSAVE is enabled */
if (use_xsave())
- fpu->state.xsave.header.xfeatures |= XFEATURE_MASK_FPSSE;
+ fpregs->xsave.header.xfeatures |= XFEATURE_MASK_FPSSE;
}

/* Fold the legacy FP storage */
- convert_to_fxsr(&fpu->state.fxsave, &env);
+ convert_to_fxsr(&fpregs->fxsave, &env);

fpregs_lock();
if (use_xsave()) {
@@ -411,10 +413,10 @@ static bool __fpu_restore_sig(void __use
*/
u64 mask = user_xfeatures | xfeatures_mask_supervisor();

- fpu->state.xsave.header.xfeatures &= mask;
- success = !os_xrstor_safe(&fpu->state.xsave, xfeatures_mask_all);
+ fpregs->xsave.header.xfeatures &= mask;
+ success = !os_xrstor_safe(&fpregs->xsave, xfeatures_mask_all);
} else {
- success = !fxrstor_safe(&fpu->state.fxsave);
+ success = !fxrstor_safe(&fpregs->fxsave);
}

if (likely(success))