linux-kernel - [PATCH 2/2] x86: replace futex_atomic_cmpxchg_inatomic() with user_atomic_cmpxchg

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Date:	Sat, 14 Dec 2013 14:25:03 +0800
From:	Qiaowei Ren <qiaowei.ren@...el.com>
To:	"H. Peter Anvin" <hpa@...or.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>
Cc:	x86@...nel.org, linux-kernel@...r.kernel.org,
	Qiaowei Ren <qiaowei.ren@...el.com>
Subject: [PATCH 2/2] x86: replace futex_atomic_cmpxchg_inatomic() with user_atomic_cmpxchg_inatomic

futex_atomic_cmpxchg_inatomic() is only the 32bit implementation of
user_atomic_cmpxchg_inatomic(). This patch replaces it with
user_atomic_cmpxchg_inatomic().

Signed-off-by: Qiaowei Ren <qiaowei.ren@...el.com>
---
 arch/x86/include/asm/futex.h |   27 ++-------------------------
 1 files changed, 2 insertions(+), 25 deletions(-)

diff --git a/arch/x86/include/asm/futex.h b/arch/x86/include/asm/futex.h
index be27ba1..a9f7de4 100644
--- a/arch/x86/include/asm/futex.h
+++ b/arch/x86/include/asm/futex.h
@@ -41,6 +41,8 @@
 		       "+m" (*uaddr), "=&r" (tem)		\
 		     : "r" (oparg), "i" (-EFAULT), "1" (0))
 
+#define futex_atomic_cmpxchg_inatomic user_atomic_cmpxchg_inatomic
+
 static inline int futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr)
 {
 	int op = (encoded_op >> 28) & 7;
@@ -107,30 +109,5 @@ static inline int futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr)
 	return ret;
 }
 
-static inline int futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
-						u32 oldval, u32 newval)
-{
-	int ret = 0;
-
-	if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
-		return -EFAULT;
-
-	asm volatile("\t" ASM_STAC "\n"
-		     "1:\t" LOCK_PREFIX "cmpxchgl %4, %2\n"
-		     "2:\t" ASM_CLAC "\n"
-		     "\t.section .fixup, \"ax\"\n"
-		     "3:\tmov     %3, %0\n"
-		     "\tjmp     2b\n"
-		     "\t.previous\n"
-		     _ASM_EXTABLE(1b, 3b)
-		     : "+r" (ret), "=a" (oldval), "+m" (*uaddr)
-		     : "i" (-EFAULT), "r" (newval), "1" (oldval)
-		     : "memory"
-	);
-
-	*uval = oldval;
-	return ret;
-}
-
 #endif
 #endif /* _ASM_X86_FUTEX_H */
-- 
1.7.1

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