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

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Date:	Tue, 19 May 2015 00:22:20 -0700
From:	tip-bot for David Hildenbrand <tipbot@...or.com>
To:	linux-tip-commits@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org, tglx@...utronix.de,
	torvalds@...ux-foundation.org, hpa@...or.com, peterz@...radead.org,
	dahi@...ux.vnet.ibm.com, mingo@...nel.org
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@...ux.vnet.ibm.com>
AuthorDate: Mon, 11 May 2015 17:52:19 +0200
Committer:  Ingo Molnar <mingo@...nel.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@...utronix.de>
Signed-off-by: David Hildenbrand <dahi@...ux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Cc: David.Laight@...LAB.COM
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: airlied@...ux.ie
Cc: akpm@...ux-foundation.org
Cc: benh@...nel.crashing.org
Cc: bigeasy@...utronix.de
Cc: borntraeger@...ibm.com
Cc: daniel.vetter@...el.com
Cc: heiko.carstens@...ibm.com
Cc: herbert@...dor.apana.org.au
Cc: hocko@...e.cz
Cc: hughd@...gle.com
Cc: mst@...hat.com
Cc: paulus@...ba.org
Cc: ralf@...ux-mips.org
Cc: schwidefsky@...ibm.com
Cc: yang.shi@...driver.com
Link: http://lkml.kernel.org/r/1431359540-32227-15-git-send-email-dahi@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@...nel.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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