diff options
Diffstat (limited to 'arch/x86/include/asm/i387.h')
| -rw-r--r-- | arch/x86/include/asm/i387.h | 17 |
1 files changed, 14 insertions, 3 deletions
diff --git a/arch/x86/include/asm/i387.h b/arch/x86/include/asm/i387.h index 8df95849721d..74c607b37e87 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); + } } /* |