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x86, fpu: Merge tolerant_fwait() 

Commit e2e75c91 merged the math exception handler, allowing both 32-bit
and 64-bit to handle math exceptions from kernel mode.  Switch to using
the 64-bit version of tolerant_fwait() without fnclex, which simply
ignores the exception if one is still pending from userspace.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
LKML-Reference: <1283563039-3466-4-git-send-email-brgerst@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
This commit is contained in:
Brian Gerst 2010-09-03 21:17:10 -04:00 committed by H. Peter Anvin
parent 6ac8bac268
commit 51115d4d45
1 changed files with 4 additions and 15 deletions
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19
arch/x86/include/asm/i387.h
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@ -77,15 +77,6 @@ static inline void sanitize_i387_state(struct task_struct *tsk)
}
#ifdef CONFIG_X86_64
/* Ignore delayed exceptions from user space */
static inline void tolerant_fwait(void)
{
asm volatile("1: fwait\n"
"2:\n"
_ASM_EXTABLE(1b, 2b));
}
static inline int fxrstor_checking(struct i387_fxsave_struct *fx)
{
int err;
@ -220,11 +211,6 @@ extern void finit_soft_fpu(struct i387_soft_struct *soft);
static inline void finit_soft_fpu(struct i387_soft_struct *soft) {}
#endif
static inline void tolerant_fwait(void)
{
asm volatile("fnclex ; fwait");
}
/* perform fxrstor iff the processor has extended states, otherwise frstor */
static inline int fxrstor_checking(struct i387_fxsave_struct *fx)
{
@ -344,7 +330,10 @@ static inline void __unlazy_fpu(struct task_struct *tsk)
static inline void __clear_fpu(struct task_struct *tsk)
{
if (task_thread_info(tsk)->status & TS_USEDFPU) {
tolerant_fwait();
/* Ignore delayed exceptions from user space */
asm volatile("1: fwait\n"
"2:\n"
_ASM_EXTABLE(1b, 2b));
task_thread_info(tsk)->status &= ~TS_USEDFPU;
stts();
}