MIPS: New macro smp_mb__before_llsc.

Replace some instances of smp_llsc_mb() with a new macro
smp_mb__before_llsc().  It is used before ll/sc sequences that are
documented as needing write barrier semantics.

The default implementation of smp_mb__before_llsc() is just smp_llsc_mb(),
so there are no changes in semantics.

Also simplify definition of smp_mb(), smp_rmb(), and smp_wmb() to be just
barrier() in the non-SMP case.

Signed-off-by: David Daney <ddaney@caviumnetworks.com>
To: linux-mips@linux-mips.org
Patchwork: http://patchwork.linux-mips.org/patch/851/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 9 insertions, 6 deletions

diff --git a/arch/mips/include/asm/barrier.h b/arch/mips/include/asm/barrier.h
index 91785dc8e94e..1a5a51c3e96f 100644
--- a/arch/mips/include/asm/barrier.h
+++ b/arch/mips/include/asm/barrier.h
@@ -131,23 +131,26 @@
 #endif /* !CONFIG_CPU_HAS_WB */
 
 #if defined(CONFIG_WEAK_ORDERING) && defined(CONFIG_SMP)
-#define __WEAK_ORDERING_MB      "       sync    \n"
+#define smp_mb()        __asm__ __volatile__("sync" : : :"memory")
+#define smp_rmb()       __asm__ __volatile__("sync" : : :"memory")
+#define smp_wmb()       __asm__ __volatile__("sync" : : :"memory")
 #else
-#define __WEAK_ORDERING_MB      "               \n"
+#define smp_mb()        barrier()
+#define smp_rmb()       barrier()
+#define smp_wmb()       barrier()
 #endif
+
 #if defined(CONFIG_WEAK_REORDERING_BEYOND_LLSC) && defined(CONFIG_SMP)
 #define __WEAK_LLSC_MB          "       sync    \n"
 #else
 #define __WEAK_LLSC_MB          "               \n"
 #endif
 
-#define smp_mb()        __asm__ __volatile__(__WEAK_ORDERING_MB : : :"memory")
-#define smp_rmb()       __asm__ __volatile__(__WEAK_ORDERING_MB : : :"memory")
-#define smp_wmb()       __asm__ __volatile__(__WEAK_ORDERING_MB : : :"memory")
-
 #define set_mb(var, value) \
         do { var = value; smp_mb(); } while (0)
 
 #define smp_llsc_mb()   __asm__ __volatile__(__WEAK_LLSC_MB : : :"memory")
 
+#define smp_mb__before_llsc() smp_llsc_mb()
+
 #endif /* __ASM_BARRIER_H */