From 33e03dedd759cc9396252d9641b25d01909a26bb Mon Sep 17 00:00:00 2001 From: Rik van Riel Date: Fri, 6 Feb 2015 15:02:02 -0500 Subject: [PATCH] x86/fpu: Introduce task_disable_lazy_fpu_restore() helper Currently there are a few magic assignments sprinkled through the code that disable lazy FPU state restoring, some more effective than others, and all equally mystifying. It would be easier to have a helper to explicitly disable lazy FPU state restoring for a task. Signed-off-by: Rik van Riel Cc: Linus Torvalds Cc: Oleg Nesterov Link: http://lkml.kernel.org/r/1423252925-14451-6-git-send-email-riel@redhat.com Signed-off-by: Borislav Petkov --- arch/x86/include/asm/fpu-internal.h | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/arch/x86/include/asm/fpu-internal.h b/arch/x86/include/asm/fpu-internal.h index 217d6d7b9cb0..9c27f44e1c5c 100644 --- a/arch/x86/include/asm/fpu-internal.h +++ b/arch/x86/include/asm/fpu-internal.h @@ -79,6 +79,16 @@ static inline void __cpu_disable_lazy_restore(unsigned int cpu) per_cpu(fpu_owner_task, cpu) = NULL; } +/* + * Used to indicate that the FPU state in memory is newer than the FPU + * state in registers, and the FPU state should be reloaded next time the + * task is run. Only safe on the current task, or non-running tasks. + */ +static inline void task_disable_lazy_fpu_restore(struct task_struct *tsk) +{ + tsk->thread.fpu.last_cpu = ~0; +} + static inline int fpu_lazy_restore(struct task_struct *new, unsigned int cpu) { return new == this_cpu_read_stable(fpu_owner_task) && -- 2.45.2