Messages in this thread Patch in this message |  | | Date | Thu, 19 Feb 2015 03:33:32 -0800 | From | tip-bot for Rik van Riel <> | Subject | [tip:x86/fpu] x86/fpu: Introduce task_disable_lazy_fpu_restore() helper |
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Commit-ID: 33e03dedd759cc9396252d9641b25d01909a26bb Gitweb: http://git.kernel.org/tip/33e03dedd759cc9396252d9641b25d01909a26bb Author: Rik van Riel <riel@redhat.com> AuthorDate: Fri, 6 Feb 2015 15:02:02 -0500 Committer: Borislav Petkov <bp@suse.de> CommitDate: Thu, 19 Feb 2015 11:15:53 +0100
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 <riel@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Link: http://lkml.kernel.org/r/1423252925-14451-6-git-send-email-riel@redhat.com Signed-off-by: Borislav Petkov <bp@suse.de> --- 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 217d6d7..9c27f44 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) &&
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