diff options
Diffstat (limited to 'arch/x86/include/asm/i387.h')
| -rw-r--r-- | arch/x86/include/asm/i387.h | 53 |
1 files changed, 38 insertions, 15 deletions
diff --git a/arch/x86/include/asm/i387.h b/arch/x86/include/asm/i387.h index a850b4d8d14d..247904945d3f 100644 --- a/arch/x86/include/asm/i387.h +++ b/arch/x86/include/asm/i387.h @@ -29,10 +29,11 @@ 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 *); +DECLARE_PER_CPU(struct task_struct *, fpu_owner_task); + extern user_regset_active_fn fpregs_active, xfpregs_active; extern user_regset_get_fn fpregs_get, xfpregs_get, fpregs_soft_get, xstateregs_get; @@ -269,6 +270,16 @@ 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.fpu.has_fpu)); + return fpu_restore_checking(&tsk->thread.fpu); } @@ -279,19 +290,21 @@ static inline int restore_fpu_checking(struct task_struct *tsk) */ static inline int __thread_has_fpu(struct task_struct *tsk) { - return tsk->thread.has_fpu; + return tsk->thread.fpu.has_fpu; } /* Must be paired with an 'stts' after! */ static inline void __thread_clear_has_fpu(struct task_struct *tsk) { - tsk->thread.has_fpu = 0; + tsk->thread.fpu.has_fpu = 0; + percpu_write(fpu_owner_task, NULL); } /* Must be paired with a 'clts' before! */ static inline void __thread_set_has_fpu(struct task_struct *tsk) { - tsk->thread.has_fpu = 1; + tsk->thread.fpu.has_fpu = 1; + percpu_write(fpu_owner_task, tsk); } /* @@ -336,30 +349,36 @@ typedef struct { int preload; } fpu_switch_t; * We don't do that yet, so "fpu_lazy_restore()" always returns * false, but some day.. */ -#define fpu_lazy_restore(tsk) (0) -#define fpu_lazy_state_intact(tsk) do { } while (0) +static inline int fpu_lazy_restore(struct task_struct *new, unsigned int cpu) +{ + return new == percpu_read_stable(fpu_owner_task) && + cpu == new->thread.fpu.last_cpu; +} -static inline fpu_switch_t switch_fpu_prepare(struct task_struct *old, struct task_struct *new) +static inline fpu_switch_t switch_fpu_prepare(struct task_struct *old, struct task_struct *new, int cpu) { fpu_switch_t fpu; fpu.preload = tsk_used_math(new) && new->fpu_counter > 5; if (__thread_has_fpu(old)) { - if (__save_init_fpu(old)) - fpu_lazy_state_intact(old); - __thread_clear_has_fpu(old); - old->fpu_counter++; + if (!__save_init_fpu(old)) + cpu = ~0; + old->thread.fpu.last_cpu = cpu; + old->thread.fpu.has_fpu = 0; /* But leave fpu_owner_task! */ /* Don't change CR0.TS if we just switch! */ if (fpu.preload) { + new->fpu_counter++; __thread_set_has_fpu(new); prefetch(new->thread.fpu.state); } else stts(); } else { old->fpu_counter = 0; + old->thread.fpu.last_cpu = ~0; if (fpu.preload) { - if (fpu_lazy_restore(new)) + new->fpu_counter++; + if (fpu_lazy_restore(new, cpu)) fpu.preload = 0; else prefetch(new->thread.fpu.state); @@ -377,8 +396,10 @@ 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); + } } /* @@ -451,8 +472,10 @@ static inline void kernel_fpu_begin(void) __save_init_fpu(me); __thread_clear_has_fpu(me); /* We do 'stts()' in kernel_fpu_end() */ - } else + } else { + percpu_write(fpu_owner_task, NULL); clts(); + } } static inline void kernel_fpu_end(void) |