diff options
Diffstat (limited to 'arch/x86/kernel/traps.c')
-rw-r--r-- | arch/x86/kernel/traps.c | 40 |
1 files changed, 8 insertions, 32 deletions
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index 77da5b475ad2..4bbe04d96744 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c | |||
@@ -571,37 +571,6 @@ asmlinkage void __attribute__((weak)) smp_threshold_interrupt(void) | |||
571 | } | 571 | } |
572 | 572 | ||
573 | /* | 573 | /* |
574 | * This gets called with the process already owning the | ||
575 | * FPU state, and with CR0.TS cleared. It just needs to | ||
576 | * restore the FPU register state. | ||
577 | */ | ||
578 | void __math_state_restore(struct task_struct *tsk) | ||
579 | { | ||
580 | /* We need a safe address that is cheap to find and that is already | ||
581 | in L1. We've just brought in "tsk->thread.has_fpu", so use that */ | ||
582 | #define safe_address (tsk->thread.has_fpu) | ||
583 | |||
584 | /* AMD K7/K8 CPUs don't save/restore FDP/FIP/FOP unless an exception | ||
585 | is pending. Clear the x87 state here by setting it to fixed | ||
586 | values. safe_address is a random variable that should be in L1 */ | ||
587 | alternative_input( | ||
588 | ASM_NOP8 ASM_NOP2, | ||
589 | "emms\n\t" /* clear stack tags */ | ||
590 | "fildl %P[addr]", /* set F?P to defined value */ | ||
591 | X86_FEATURE_FXSAVE_LEAK, | ||
592 | [addr] "m" (safe_address)); | ||
593 | |||
594 | /* | ||
595 | * Paranoid restore. send a SIGSEGV if we fail to restore the state. | ||
596 | */ | ||
597 | if (unlikely(restore_fpu_checking(tsk))) { | ||
598 | __thread_fpu_end(tsk); | ||
599 | force_sig(SIGSEGV, tsk); | ||
600 | return; | ||
601 | } | ||
602 | } | ||
603 | |||
604 | /* | ||
605 | * 'math_state_restore()' saves the current math information in the | 574 | * 'math_state_restore()' saves the current math information in the |
606 | * old math state array, and gets the new ones from the current task | 575 | * old math state array, and gets the new ones from the current task |
607 | * | 576 | * |
@@ -631,7 +600,14 @@ void math_state_restore(void) | |||
631 | } | 600 | } |
632 | 601 | ||
633 | __thread_fpu_begin(tsk); | 602 | __thread_fpu_begin(tsk); |
634 | __math_state_restore(tsk); | 603 | /* |
604 | * Paranoid restore. send a SIGSEGV if we fail to restore the state. | ||
605 | */ | ||
606 | if (unlikely(restore_fpu_checking(tsk))) { | ||
607 | __thread_fpu_end(tsk); | ||
608 | force_sig(SIGSEGV, tsk); | ||
609 | return; | ||
610 | } | ||
635 | 611 | ||
636 | tsk->fpu_counter++; | 612 | tsk->fpu_counter++; |
637 | } | 613 | } |