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From: Vineet Gupta <Vineet.Gupta1@synopsys.com>
To: "Peter Zijlstra (Intel)" <peterz@infradead.org>,
	Thomas Gleixner <tglx@linutronix.de>
Cc: Michel Lespinasse <walken@google.com>,
	<arc-linux-dev@synopsys.com>, lkml <linux-kernel@vger.kernel.org>,
	Vineet Gupta <Vineet.Gupta1@synopsys.com>
Subject: [PATCH 2/4] ARC: futex cosmetics
Date: Thu, 6 Aug 2015 18:05:21 +0530	[thread overview]
Message-ID: <1438864523-31340-3-git-send-email-vgupta@synopsys.com> (raw)
In-Reply-To: <1438864523-31340-1-git-send-email-vgupta@synopsys.com>

Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Michel Lespinasse <walken@google.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
---
 arch/arc/include/asm/futex.h | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/arch/arc/include/asm/futex.h b/arch/arc/include/asm/futex.h
index 160656d0a15a..82902ff0517f 100644
--- a/arch/arc/include/asm/futex.h
+++ b/arch/arc/include/asm/futex.h
@@ -94,6 +94,7 @@ static inline int futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr)
 		__futex_atomic_op("mov %0, %3", ret, oldval, uaddr, oparg);
 		break;
 	case FUTEX_OP_ADD:
+		/* oldval = *uaddr; *uaddr += oparg ; ret = *uaddr */
 		__futex_atomic_op("add %0, %1, %3", ret, oldval, uaddr, oparg);
 		break;
 	case FUTEX_OP_OR:
@@ -147,12 +148,12 @@ static inline int futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr)
  *      -user access r/w fails: return -EFAULT
  */
 static inline int
-futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, u32 oldval,
-					u32 newval)
+futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, u32 expval,
+			      u32 newval)
 {
-	u32 val;
+	u32 existval;
 
-	if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
+	if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
 		return -EFAULT;
 
 	smp_mb();
@@ -178,14 +179,14 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, u32 oldval,
 	"	.word   1b, 4b	\n"
 	"	.word   2b, 4b	\n"
 	"	.previous\n"
-	: "=&r"(val)
-	: "r"(oldval), "r"(newval), "r"(uaddr), "ir"(-EFAULT)
+	: "=&r"(existval)
+	: "r"(expval), "r"(newval), "r"(uaddr), "ir"(-EFAULT)
 	: "cc", "memory");
 
 	smp_mb();
 
-	*uval = val;
-	return val;
+	*uval = existval;
+	return existval;
 }
 
 #endif
-- 
1.9.1


  parent reply	other threads:[~2015-08-06 12:36 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-08-06 12:35 [PATCH 0/4] ARC futex fixes Vineet Gupta
2015-08-06 12:35 ` [PATCH 1/4] ARC: add barriers to futex code Vineet Gupta
2015-08-06 13:15   ` David Hildenbrand
2015-08-06 13:28     ` Vineet Gupta
2015-08-06 13:48   ` Peter Zijlstra
2015-08-06 14:11     ` Will Deacon
2015-08-07 11:40     ` Peter Zijlstra
2015-08-06 12:35 ` Vineet Gupta [this message]
2015-08-06 12:35 ` [PATCH 3/4] ARC: make futex_atomic_cmpxchg_inatomic() return bimodal Vineet Gupta
2015-08-06 12:35 ` [PATCH 4/4] ARC: Enable HAVE_FUTEX_CMPXCHG Vineet Gupta
2015-08-06 13:46 ` [PATCH 5/4] ARC: ensure futex ops are atomic in !LLSC config Vineet Gupta
2015-08-17  7:46 ` [PATCH 0/4] ARC futex fixes Vineet Gupta

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