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-rw-r--r--include/asm-powerpc/system.h9
1 files changed, 9 insertions, 0 deletions
diff --git a/include/asm-powerpc/system.h b/include/asm-powerpc/system.h
index 7307aa77567..4c9f5229e83 100644
--- a/include/asm-powerpc/system.h
+++ b/include/asm-powerpc/system.h
@@ -53,6 +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;