From: Greg KH <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org,
alan@lxorguk.ukuu.org.uk
Subject: [ 05/10] i387: move TS_USEDFPU clearing out of __save_init_fpu and into callers
Date: Thu, 23 Feb 2012 16:02:25 -0800 [thread overview]
Message-ID: <20120224000220.759957746@linuxfoundation.org> (raw)
In-Reply-To: <20120224000510.GA1005@kroah.com>
3.2-stable review patch. If anyone has any objections, please let me know.
------------------
From: Linus Torvalds <torvalds@linux-foundation.org>
commit b6c66418dcad0fcf83cd1d0a39482db37bf4fc41 upstream.
Touching TS_USEDFPU without touching CR0.TS is confusing, so don't do
it. By moving it into the callers, we always do the TS_USEDFPU next to
the CR0.TS accesses in the source code, and it's much easier to see how
the two go hand in hand.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/include/asm/i387.h | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
--- a/arch/x86/include/asm/i387.h
+++ b/arch/x86/include/asm/i387.h
@@ -259,7 +259,6 @@ static inline void fpu_save_init(struct
static inline void __save_init_fpu(struct task_struct *tsk)
{
fpu_save_init(&tsk->thread.fpu);
- task_thread_info(tsk)->status &= ~TS_USEDFPU;
}
static inline int fpu_fxrstor_checking(struct fpu *fpu)
@@ -290,6 +289,7 @@ static inline void __unlazy_fpu(struct t
{
if (task_thread_info(tsk)->status & TS_USEDFPU) {
__save_init_fpu(tsk);
+ task_thread_info(tsk)->status &= ~TS_USEDFPU;
stts();
} else
tsk->fpu_counter = 0;
@@ -356,9 +356,11 @@ static inline void kernel_fpu_begin(void
WARN_ON_ONCE(!irq_fpu_usable());
preempt_disable();
- if (me->status & TS_USEDFPU)
+ if (me->status & TS_USEDFPU) {
__save_init_fpu(me->task);
- else
+ me->status &= ~TS_USEDFPU;
+ /* We do 'stts()' in kernel_fpu_end() */
+ } else
clts();
}
@@ -449,6 +451,7 @@ static inline void save_init_fpu(struct
WARN_ON_ONCE(!(task_thread_info(tsk)->status & TS_USEDFPU));
preempt_disable();
__save_init_fpu(tsk);
+ task_thread_info(tsk)->status &= ~TS_USEDFPU;
stts();
preempt_enable();
}
next prev parent reply other threads:[~2012-02-24 0:08 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-24 0:05 [ 00/10] 3.2.8-stable review Greg KH
2012-02-24 0:02 ` [ 01/10] i387: math_state_restore() isnt called from asm Greg KH
2012-02-24 0:02 ` [ 02/10] i387: make irq_fpu_usable() tests more robust Greg KH
2012-02-24 0:02 ` [ 03/10] i387: fix sense of sanity check Greg KH
2012-02-24 0:02 ` [ 04/10] i387: fix x86-64 preemption-unsafe user stack save/restore Greg KH
2012-02-24 0:02 ` Greg KH [this message]
2012-02-24 0:02 ` [ 06/10] i387: dont ever touch TS_USEDFPU directly, use helper functions Greg KH
2012-02-24 0:02 ` [ 07/10] i387: do not preload FPU state at task switch time Greg KH
2012-02-24 0:02 ` [ 08/10] i387: move AMD K7/K8 fpu fxsave/fxrstor workaround from save to restore Greg KH
2012-02-24 0:02 ` [ 09/10] i387: move TS_USEDFPU flag from thread_info to task_struct Greg KH
2012-02-24 0:02 ` [ 10/10] i387: re-introduce FPU state preloading at context switch time Greg KH
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