1 files changed, 17 insertions, 9 deletions

diff --git a/include/asm-powerpc/system.h b/include/asm-powerpc/system.h
index d075725bf444..4c9f5229e833 100644
--- a/include/asm-powerpc/system.h
+++ b/include/asm-powerpc/system.h
@@ -39,7 +39,6 @@
 #define read_barrier_depends()  do { } while(0)
 
 #define set_mb(var, value)      do { var = value; mb(); } while (0)
-#define set_wmb(var, value)     do { var = value; wmb(); } while (0)
 
 #ifdef __KERNEL__
 #ifdef CONFIG_SMP
@@ -54,6 +53,15 @@
 #define smp_read_barrier_depends()      do { } while(0)
 #endif /* CONFIG_SMP */
 
+/*
+ * This is a barrier which prevents following instructions from being
+ * started until the value of the argument x is known.  For example, if
+ * x is a variable loaded from memory, this prevents following
+ * instructions from being executed until the load has been performed.
+ */
+#define data_barrier(x) \
+        asm volatile("twi 0,%0,0; isync" : : "r" (x) : "memory");
+
 struct task_struct;
 struct pt_regs;
 
@@ -220,8 +228,8 @@ __xchg_u32(volatile void *p, unsigned long val)
 "       stwcx.  %3,0,%2 \n\
         bne-    1b"
         ISYNC_ON_SMP
-        : "=&r" (prev), "=m" (*(volatile unsigned int *)p)
-        : "r" (p), "r" (val), "m" (*(volatile unsigned int *)p)
+        : "=&r" (prev), "+m" (*(volatile unsigned int *)p)
+        : "r" (p), "r" (val)
         : "cc", "memory");
 
         return prev;
@@ -240,8 +248,8 @@ __xchg_u64(volatile void *p, unsigned long val)
 "       stdcx.  %3,0,%2 \n\
         bne-    1b"
         ISYNC_ON_SMP
-        : "=&r" (prev), "=m" (*(volatile unsigned long *)p)
-        : "r" (p), "r" (val), "m" (*(volatile unsigned long *)p)
+        : "=&r" (prev), "+m" (*(volatile unsigned long *)p)
+        : "r" (p), "r" (val)
         : "cc", "memory");
 
         return prev;
@@ -299,8 +307,8 @@ __cmpxchg_u32(volatile unsigned int *p, unsigned long old, unsigned long new)
         ISYNC_ON_SMP
         "\n\
 2:"
-        : "=&r" (prev), "=m" (*p)
-        : "r" (p), "r" (old), "r" (new), "m" (*p)
+        : "=&r" (prev), "+m" (*p)
+        : "r" (p), "r" (old), "r" (new)
         : "cc", "memory");
 
         return prev;
@@ -322,8 +330,8 @@ __cmpxchg_u64(volatile unsigned long *p, unsigned long old, unsigned long new)
         ISYNC_ON_SMP
         "\n\
 2:"
-        : "=&r" (prev), "=m" (*p)
-        : "r" (p), "r" (old), "r" (new), "m" (*p)
+        : "=&r" (prev), "+m" (*p)
+        : "r" (p), "r" (old), "r" (new)
         : "cc", "memory");
 
         return prev;