summaryrefslogtreecommitdiffstats
path: root/arch/x86/include/asm/i387.h
diff options
context:
space:
mode:
Diffstat (limited to 'arch/x86/include/asm/i387.h')
-rw-r--r--arch/x86/include/asm/i387.h17
1 files changed, 14 insertions, 3 deletions
diff --git a/arch/x86/include/asm/i387.h b/arch/x86/include/asm/i387.h
index 8df9584..74c607b 100644
--- a/arch/x86/include/asm/i387.h
+++ b/arch/x86/include/asm/i387.h
@@ -29,7 +29,6 @@ extern unsigned int sig_xstate_size;
extern void fpu_init(void);
extern void mxcsr_feature_mask_init(void);
extern int init_fpu(struct task_struct *child);
-extern void __math_state_restore(struct task_struct *);
extern void math_state_restore(void);
extern int dump_fpu(struct pt_regs *, struct user_i387_struct *);
@@ -269,6 +268,16 @@ static inline int fpu_restore_checking(struct fpu *fpu)
static inline int restore_fpu_checking(struct task_struct *tsk)
{
+ /* AMD K7/K8 CPUs don't save/restore FDP/FIP/FOP unless an exception
+ is pending. Clear the x87 state here by setting it to fixed
+ values. "m" is a random variable that should be in L1 */
+ alternative_input(
+ ASM_NOP8 ASM_NOP2,
+ "emms\n\t" /* clear stack tags */
+ "fildl %P[addr]", /* set F?P to defined value */
+ X86_FEATURE_FXSAVE_LEAK,
+ [addr] "m" (tsk->thread.has_fpu));
+
return fpu_restore_checking(&tsk->thread.fpu);
}
@@ -378,8 +387,10 @@ static inline fpu_switch_t switch_fpu_prepare(struct task_struct *old, struct ta
*/
static inline void switch_fpu_finish(struct task_struct *new, fpu_switch_t fpu)
{
- if (fpu.preload)
- __math_state_restore(new);
+ if (fpu.preload) {
+ if (unlikely(restore_fpu_checking(new)))
+ __thread_fpu_end(new);
+ }
}
/*
OpenPOWER on IntegriCloud