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Diffstat (limited to 'arch/x86/include/asm/i387.h')
-rw-r--r--arch/x86/include/asm/i387.h53
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)