1 files changed, 34 insertions, 41 deletions

diff --git a/arch/arm/include/asm/cmpxchg.h b/arch/arm/include/asm/cmpxchg.h
index d41d7cbf0ad..abb2c3769b0 100644
--- a/arch/arm/include/asm/cmpxchg.h
+++ b/arch/arm/include/asm/cmpxchg.h
@@ -2,6 +2,7 @@
 #define __ASM_ARM_CMPXCHG_H
 
 #include <linux/irqflags.h>
+#include <linux/prefetch.h>
 #include <asm/barrier.h>
 
 #if defined(CONFIG_CPU_SA1100) || defined(CONFIG_CPU_SA110)
@@ -35,6 +36,7 @@ static inline unsigned long __xchg(unsigned long x, volatile void *ptr, int size
 #endif
 
 	smp_mb();
+	prefetchw((const void *)ptr);
 
 	switch (size) {
 #if __LINUX_ARM_ARCH__ >= 6
@@ -138,6 +140,8 @@ static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old,
 {
 	unsigned long oldval, res;
 
+	prefetchw((const void *)ptr);
+
 	switch (size) {
 #ifndef CONFIG_CPU_V6	/* min ARCH >= ARMv6K */
 	case 1:
@@ -223,45 +227,32 @@ static inline unsigned long __cmpxchg_local(volatile void *ptr,
 	return ret;
 }
 
-#define cmpxchg_local(ptr,o,n)						\
-	((__typeof__(*(ptr)))__cmpxchg_local((ptr),			\
-				       (unsigned long)(o),		\
-				       (unsigned long)(n),		\
-				       sizeof(*(ptr))))
-
-#ifndef CONFIG_CPU_V6	/* min ARCH >= ARMv6K */
-
-/*
- * Note : ARMv7-M (currently unsupported by Linux) does not support
- * ldrexd/strexd. If ARMv7-M is ever supported by the Linux kernel, it should
- * not be allowed to use __cmpxchg64.
- */
-static inline unsigned long long __cmpxchg64(volatile void *ptr,
+static inline unsigned long long __cmpxchg64(unsigned long long *ptr,
 					     unsigned long long old,
 					     unsigned long long new)
 {
-	register unsigned long long oldval asm("r0");
-	register unsigned long long __old asm("r2") = old;
-	register unsigned long long __new asm("r4") = new;
+	unsigned long long oldval;
 	unsigned long res;
 
-	do {
-		asm volatile(
-		"	@ __cmpxchg8\n"
-		"	ldrexd	%1, %H1, [%2]\n"
-		"	mov	%0, #0\n"
-		"	teq	%1, %3\n"
-		"	teqeq	%H1, %H3\n"
-		"	strexdeq %0, %4, %H4, [%2]\n"
-			: "=&r" (res), "=&r" (oldval)
-			: "r" (ptr), "Ir" (__old), "r" (__new)
-			: "memory", "cc");
-	} while (res);
+	prefetchw(ptr);
+
+	__asm__ __volatile__(
+"1:	ldrexd		%1, %H1, [%3]\n"
+"	teq		%1, %4\n"
+"	teqeq		%H1, %H4\n"
+"	bne		2f\n"
+"	strexd		%0, %5, %H5, [%3]\n"
+"	teq		%0, #0\n"
+"	bne		1b\n"
+"2:"
+	: "=&r" (res), "=&r" (oldval), "+Qo" (*ptr)
+	: "r" (ptr), "r" (old), "r" (new)
+	: "cc");
 
 	return oldval;
 }
 
-static inline unsigned long long __cmpxchg64_mb(volatile void *ptr,
+static inline unsigned long long __cmpxchg64_mb(unsigned long long *ptr,
 						unsigned long long old,
 						unsigned long long new)
 {
@@ -274,21 +265,23 @@ static inline unsigned long long __cmpxchg64_mb(volatile void *ptr,
 	return ret;
 }
 
-#define cmpxchg64(ptr,o,n)						\
+#define cmpxchg_local(ptr,o,n)						\
+	((__typeof__(*(ptr)))__cmpxchg_local((ptr),			\
+				       (unsigned long)(o),		\
+				       (unsigned long)(n),		\
+				       sizeof(*(ptr))))
+
+#define cmpxchg64(ptr, o, n)						\
 	((__typeof__(*(ptr)))__cmpxchg64_mb((ptr),			\
-					    (unsigned long long)(o),	\
-					    (unsigned long long)(n)))
+					(unsigned long long)(o),	\
+					(unsigned long long)(n)))
 
-#define cmpxchg64_local(ptr,o,n)					\
+#define cmpxchg64_relaxed(ptr, o, n)					\
 	((__typeof__(*(ptr)))__cmpxchg64((ptr),				\
-					 (unsigned long long)(o),	\
-					 (unsigned long long)(n)))
-
-#else /* min ARCH = ARMv6 */
+					(unsigned long long)(o),	\
+					(unsigned long long)(n)))
 
-#define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n))
-
-#endif
+#define cmpxchg64_local(ptr, o, n)	cmpxchg64_relaxed((ptr), (o), (n))
 
 #endif	/* __LINUX_ARM_ARCH__ >= 6 */