[tip:sched/core] sched/preempt, MIPS: Properly lock access to the FPU

[tip-bot for David Hildenbrand]

Commit-ID:  76deabd1867d6d2895152f31fdec819e3505738b
Gitweb:     http://git.kernel.org/tip/76deabd1867d6d2895152f31fdec819e3505738b
Author:     David Hildenbrand <dahi@xxxxxxxxxxxxxxxxxx>
AuthorDate: Mon, 11 May 2015 17:52:19 +0200
Committer:  Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Tue, 19 May 2015 08:39:18 +0200

sched/preempt, MIPS: Properly lock access to the FPU

Let's always disable preemption and pagefaults when locking the fpu,
so we can be sure that the owner won't change in between.

This is a preparation for pagefault_disable() not touching preemption
anymore.

Reviewed-and-tested-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: David Hildenbrand <dahi@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: David.Laight@xxxxxxxxxx
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: airlied@xxxxxxxx
Cc: akpm@xxxxxxxxxxxxxxxxxxxx
Cc: benh@xxxxxxxxxxxxxxxxxxx
Cc: bigeasy@xxxxxxxxxxxxx
Cc: borntraeger@xxxxxxxxxx
Cc: daniel.vetter@xxxxxxxxx
Cc: heiko.carstens@xxxxxxxxxx
Cc: herbert@xxxxxxxxxxxxxxxxxxx
Cc: hocko@xxxxxxx
Cc: hughd@xxxxxxxxxx
Cc: mst@xxxxxxxxxx
Cc: paulus@xxxxxxxxx
Cc: ralf@xxxxxxxxxxxxxx
Cc: schwidefsky@xxxxxxxxxx
Cc: yang.shi@xxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/1431359540-32227-15-git-send-email-dahi@xxxxxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
 arch/mips/kernel/signal-common.h | 9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/arch/mips/kernel/signal-common.h b/arch/mips/kernel/signal-common.h
index 06805e0..0b85f82 100644
--- a/arch/mips/kernel/signal-common.h
+++ b/arch/mips/kernel/signal-common.h
@@ -28,12 +28,7 @@ extern void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs,
 extern int fpcsr_pending(unsigned int __user *fpcsr);
 
 /* Make sure we will not lose FPU ownership */
-#ifdef CONFIG_PREEMPT
-#define lock_fpu_owner()	preempt_disable()
-#define unlock_fpu_owner()	preempt_enable()
-#else
-#define lock_fpu_owner()	pagefault_disable()
-#define unlock_fpu_owner()	pagefault_enable()
-#endif
+#define lock_fpu_owner()	({ preempt_disable(); pagefault_disable(); })
+#define unlock_fpu_owner()	({ pagefault_enable(); preempt_enable(); })
 
 #endif	/* __SIGNAL_COMMON_H */
--
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