FRV: Don't make smp_{r, w, }mb() interpolate MEMBAR when CONFIG_SMP=n [try #2]
Don't make smp_{r,w,}mb() interpolate a MEMBAR instruction when CONFIG_SMP=n as
SMP memory barries on UP systems should interpolate a compiler barrier only.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/asm-frv/system.h b/include/asm-frv/system.h
index 2c57f473..30a67a9 100644
--- a/include/asm-frv/system.h
+++ b/include/asm-frv/system.h
@@ -179,14 +179,23 @@
#define mb() asm volatile ("membar" : : :"memory")
#define rmb() asm volatile ("membar" : : :"memory")
#define wmb() asm volatile ("membar" : : :"memory")
-#define set_mb(var, value) do { var = value; mb(); } while (0)
+#define read_barrier_depends() barrier()
-#define smp_mb() mb()
-#define smp_rmb() rmb()
-#define smp_wmb() wmb()
-
-#define read_barrier_depends() do {} while(0)
+#ifdef CONFIG_SMP
+#define smp_mb() mb()
+#define smp_rmb() rmb()
+#define smp_wmb() wmb()
#define smp_read_barrier_depends() read_barrier_depends()
+#define set_mb(var, value) \
+ do { xchg(&var, (value)); } while (0)
+#else
+#define smp_mb() barrier()
+#define smp_rmb() barrier()
+#define smp_wmb() barrier()
+#define smp_read_barrier_depends() do {} while(0)
+#define set_mb(var, value) \
+ do { var = (value); barrier(); } while (0)
+#endif
#define HARD_RESET_NOW() \
do { \