Commit-ID: a9241ea5fd709fc935dade130f4e3b2612bbe9e3
Gitweb: http://git.kernel.org/tip/a9241ea5fd709fc935dade130f4e3b2612bbe9e3
Author: Oleg Nesterov <o...@redhat.com>
AuthorDate: Fri, 6 Feb 2015 15:01:58 -0500
Committer: Borislav Petkov <b...@suse.de>
CommitDate: Thu, 19 Feb 2015 11:12:40 +0100
x86/fpu: Don't reset thread.fpu_counter
The "else" branch clears ->fpu_counter as a remnant of the lazy FPU
usage counting:
e07e23e1fd30 ("[PATCH] non lazy "sleazy" fpu implementation")
However, switch_fpu_prepare() does this now so that else branch is
superfluous.
If we do use_eager_fpu(), then this has no effect. Otherwise, if we
actually wanted to prevent fpu preload after the context switch we would
need to reset it unconditionally, even if __thread_has_fpu().
Signed-off-by: Oleg Nesterov <o...@redhat.com>
Signed-off-by: Rik van Riel <r...@redhat.com>
Cc: Linus Torvalds <torva...@linux-foundation.org>
Link: http://lkml.kernel.org/r/1423252925-14451-2-git-send-email-r...@redhat.com
Signed-off-by: Borislav Petkov <b...@suse.de>
---
arch/x86/kernel/i387.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c
index a9a4229..4d0db9e 100644
--- a/arch/x86/kernel/i387.c
+++ b/arch/x86/kernel/i387.c
@@ -108,8 +108,7 @@ void unlazy_fpu(struct task_struct *tsk)
if (__thread_has_fpu(tsk)) {
__save_init_fpu(tsk);
__thread_fpu_end(tsk);
- } else
- tsk->thread.fpu_counter = 0;
+ }
preempt_enable();
}
EXPORT_SYMBOL(unlazy_fpu);
--
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