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Subject[tip:sched/core] sched/preempt, MIPS: Properly lock access to the FPU
Commit-ID:  76deabd1867d6d2895152f31fdec819e3505738b
Gitweb: http://git.kernel.org/tip/76deabd1867d6d2895152f31fdec819e3505738b
Author: David Hildenbrand <dahi@linux.vnet.ibm.com>
AuthorDate: Mon, 11 May 2015 17:52:19 +0200
Committer: Ingo Molnar <mingo@kernel.org>
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@linutronix.de>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: David.Laight@ACULAB.COM
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: airlied@linux.ie
Cc: akpm@linux-foundation.org
Cc: benh@kernel.crashing.org
Cc: bigeasy@linutronix.de
Cc: borntraeger@de.ibm.com
Cc: daniel.vetter@intel.com
Cc: heiko.carstens@de.ibm.com
Cc: herbert@gondor.apana.org.au
Cc: hocko@suse.cz
Cc: hughd@google.com
Cc: mst@redhat.com
Cc: paulus@samba.org
Cc: ralf@linux-mips.org
Cc: schwidefsky@de.ibm.com
Cc: yang.shi@windriver.com
Link: http://lkml.kernel.org/r/1431359540-32227-15-git-send-email-dahi@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
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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