[PATCH] ARM SMP: Add ARMv6 memory barriers
Convert explicit gcc asm-based memory barriers into smp_mb() calls.
These change between barrier() and the ARMv6 data memory barrier
instruction depending on whether ARMv6 SMP is enabled.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/include/asm-arm/system.h b/include/asm-arm/system.h
index 3f9c362..8efa4eb 100644
--- a/include/asm-arm/system.h
+++ b/include/asm-arm/system.h
@@ -139,7 +139,12 @@
#define vectors_high() (0)
#endif
+#if __LINUX_ARM_ARCH__ >= 6
+#define mb() __asm__ __volatile__ ("mcr p15, 0, %0, c7, c10, 5" \
+ : : "r" (0) : "memory")
+#else
#define mb() __asm__ __volatile__ ("" : : : "memory")
+#endif
#define rmb() mb()
#define wmb() mb()
#define read_barrier_depends() do { } while(0)