Commit-ID: 531bd721812cad4b7f7158b246fba8303b555be7
Gitweb: https://git.kernel.org/tip/531bd721812cad4b7f7158b246fba8303b555be7
Author: Sebastian Andrzej Siewior <[email protected]>
AuthorDate: Tue, 30 Apr 2019 10:31:26 +0200
Committer: Ingo Molnar <[email protected]>
CommitDate: Tue, 30 Apr 2019 13:07:54 +0200
x86/fpu: Remove unnecessary saving of FPU registers in
copy_fpstate_to_sigframe()
Since commit:
eeec00d73be2e ("x86/fpu: Fault-in user stack if copy_fpstate_to_sigframe()
fails")
there is no need to have FPU registers saved if
copy_fpregs_to_sigframe() fails, because we retry it after we resolved
the fault condition.
Saving the registers is not wrong but it is not necessary and it forces us
to load the FPU registers on the retry attempt.
Don't save the FPU registers if copy_fpstate_to_sigframe() fails.
Signed-off-by: Sebastian Andrzej Siewior <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Fenghua Yu <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: [email protected]
Cc: Linus Torvalds <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
---
arch/x86/kernel/fpu/signal.c | 6 +-----
1 file changed, 1 insertion(+), 5 deletions(-)
diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c
index 6d6c2d6afde4..08c5059dc4ec 100644
--- a/arch/x86/kernel/fpu/signal.c
+++ b/arch/x86/kernel/fpu/signal.c
@@ -157,10 +157,9 @@ static inline int copy_fpregs_to_sigframe(struct
xregs_state __user *buf)
*/
int copy_fpstate_to_sigframe(void __user *buf, void __user *buf_fx, int size)
{
- struct fpu *fpu = ¤t->thread.fpu;
struct task_struct *tsk = current;
int ia32_fxstate = (buf != buf_fx);
- int ret = -EFAULT;
+ int ret;
ia32_fxstate &= (IS_ENABLED(CONFIG_X86_32) ||
IS_ENABLED(CONFIG_IA32_EMULATION));
@@ -187,9 +186,6 @@ retry:
pagefault_disable();
ret = copy_fpregs_to_sigframe(buf_fx);
pagefault_enable();
- if (ret && !test_thread_flag(TIF_NEED_FPU_LOAD))
- copy_fpregs_to_fpstate(fpu);
- set_thread_flag(TIF_NEED_FPU_LOAD);
fpregs_unlock();
if (ret) {
