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x86, fpu: remove unnecessary user_fpu_end() in save_xstate_sig()

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Few lines below we do drop_fpu() which is more safer. Remove the
unnecessary user_fpu_end() in save_xstate_sig(), which allows
the drop_fpu() to ignore any pending exceptions from the user-space
and drop the current fpu.

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Link: http://lkml.kernel.org/r/1345842782-24175-3-git-send-email-suresh.b.siddha@intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
This commit is contained in:
Suresh Siddha 2012-08-24 14:12:58 -07:00 committed by H. Peter Anvin
parent e962591749
commit 377ffbcc53
2 changed files with 3 additions and 15 deletions
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17
arch/x86/include/asm/fpu-internal.h
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@ -412,22 +412,11 @@ static inline void __drop_fpu(struct task_struct *tsk)
}
/*
* The actual user_fpu_begin/end() functions
* need to be preemption-safe.
* Need to be preemption-safe.
*
* NOTE! user_fpu_end() must be used only after you
* have saved the FP state, and user_fpu_begin() must
* be used only immediately before restoring it.
* These functions do not do any save/restore on
* their own.
* NOTE! user_fpu_begin() must be used only immediately before restoring
* it. This function does not do any save/restore on their own.
*/
static inline void user_fpu_end(void)
{
preempt_disable();
__thread_fpu_end(current);
preempt_enable();
}
static inline void user_fpu_begin(void)
{
preempt_disable();

1
arch/x86/kernel/xsave.c
View file

@ -255,7 +255,6 @@ int save_xstate_sig(void __user *buf, void __user *buf_fx, int size)
/* Update the thread's fxstate to save the fsave header. */
if (ia32_fxstate)
fpu_fxsave(&tsk->thread.fpu);
user_fpu_end();
} else {
sanitize_i387_state(tsk);
if (__copy_to_user(buf_fx, xsave, xstate_size))