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Commit 51115d4d authored by Brian Gerst's avatar Brian Gerst Committed by H. Peter Anvin
Browse files

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: default avatarBrian Gerst <brgerst@gmail.com>
Acked-by: default avatarPekka 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: default avatarH. Peter Anvin <hpa@linux.intel.com>
parent 6ac8bac2

arch/x86/include/asm/i387.h

+4 −15
Original line number Diff line number Diff line
@@ -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();

	}