ieee1394: merge from Linus

[mv-sheeva.git] / include / asm-powerpc / system.h

diff --git a/include/asm-powerpc/system.h b/include/asm-powerpc/system.h
index c6569516ba3536269d03a38c5a18ae4029eaf480..4c9f5229e83355a6af341841e6230277422bd39b 100644 (file)
--- 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;