From: Rik van Riel <[email protected]> This change has no impact on normal tasks, but it allows tasks with multiple FPU states(like a KVM vcpu thread) to check whether its other FPU state is still loaded.
Exported so KVM can use it. Signed-off-by: Rik van Riel <[email protected]> --- arch/x86/include/asm/fpu-internal.h | 15 ++++++++------- arch/x86/kernel/cpu/common.c | 5 +++-- arch/x86/kernel/i387.c | 2 +- 3 files changed, 12 insertions(+), 10 deletions(-) diff --git a/arch/x86/include/asm/fpu-internal.h b/arch/x86/include/asm/fpu-internal.h index a5a40c7..8546c0a 100644 --- a/arch/x86/include/asm/fpu-internal.h +++ b/arch/x86/include/asm/fpu-internal.h @@ -42,7 +42,7 @@ extern unsigned int mxcsr_feature_mask; extern void fpu_init(void); extern void eager_fpu_init(void); -DECLARE_PER_CPU(struct task_struct *, fpu_owner_task); +DECLARE_PER_CPU(struct fpu *, fpu_owner); extern void convert_from_fxsr(struct user_i387_ia32_struct *env, struct task_struct *tsk); @@ -318,14 +318,14 @@ static inline int __thread_has_fpu(struct task_struct *tsk) static inline void __thread_clear_has_fpu(struct task_struct *tsk) { tsk->thread.fpu.has_fpu = 0; - this_cpu_write(fpu_owner_task, NULL); + this_cpu_write(fpu_owner, NULL); } /* Must be paired with a 'clts' before! */ static inline void __thread_set_has_fpu(struct task_struct *tsk) { tsk->thread.fpu.has_fpu = 1; - this_cpu_write(fpu_owner_task, tsk); + this_cpu_write(fpu_owner, &tsk->thread.fpu); } /* @@ -394,13 +394,14 @@ static inline void drop_init_fpu(struct task_struct *tsk) */ static inline void __cpu_disable_lazy_restore(unsigned int cpu) { - per_cpu(fpu_owner_task, cpu) = NULL; + per_cpu(fpu_owner, cpu) = NULL; } static inline int fpu_lazy_restore(struct task_struct *new, unsigned int cpu) { - return new == this_cpu_read_stable(fpu_owner_task) && - cpu == new->thread.fpu.last_cpu; + struct fpu *new_fpu = &new->thread.fpu; + return new_fpu == this_cpu_read_stable(fpu_owner) && + cpu == new_fpu->last_cpu; } static inline void switch_fpu_prepare(struct task_struct *old, struct task_struct *new, int cpu) @@ -421,7 +422,7 @@ static inline void switch_fpu_prepare(struct task_struct *old, struct task_struc cpu = ~0; old->thread.fpu.last_cpu = cpu; - old->thread.fpu.has_fpu = 0; /* But leave fpu_owner_task! */ + old->thread.fpu.has_fpu = 0; /* But leave fpu_owner! */ /* Don't change CR0.TS if we just switch! */ if (preload) { diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 36837bb..ad4d1a9 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -1143,8 +1143,9 @@ DEFINE_PER_CPU(unsigned int, irq_count) __visible = -1; DEFINE_PER_CPU(int, __preempt_count) = INIT_PREEMPT_COUNT; EXPORT_PER_CPU_SYMBOL(__preempt_count); -/* Task that currently has its FPU state loaded on the CPU. */ -DEFINE_PER_CPU(struct task_struct *, fpu_owner_task); +/* FPU state that is currently loaded on the CPU. */ +DEFINE_PER_CPU(struct fpu *, fpu_owner); +EXPORT_PER_CPU_SYMBOL_GPL(fpu_owner); /* * Special IST stacks which the CPU switches to when it calls diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c index a9a4229..c98f88d 100644 --- a/arch/x86/kernel/i387.c +++ b/arch/x86/kernel/i387.c @@ -78,7 +78,7 @@ void __kernel_fpu_begin(void) __save_init_fpu(me); /* We do 'stts()' in __kernel_fpu_end() */ } else if (!use_eager_fpu()) { - this_cpu_write(fpu_owner_task, NULL); + this_cpu_write(fpu_owner, NULL); clts(); } } -- 1.9.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
