sparc64: Make lock backoff really a NOP on UP builds.

As noticed by Mikulas Patocka, the backoff macros don't
completely nop out for UP builds, we still get a
branch always and a delay slot nop.

Fix this by making the branch to the backoff spin loop
selective, then we can nop out the spin loop completely.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 8 insertions, 3 deletions

diff --git a/arch/sparc/include/asm/backoff.h b/arch/sparc/include/asm/backoff.h
index fa1fdf67e350..db3af0d30fb1 100644
--- a/arch/sparc/include/asm/backoff.h
+++ b/arch/sparc/include/asm/backoff.h
@@ -8,6 +8,9 @@
 #define BACKOFF_SETUP(reg)      \
         mov     1, reg
 
+#define BACKOFF_LABEL(spin_label, continue_label) \
+        spin_label
+
 #define BACKOFF_SPIN(reg, tmp, label)   \
         mov     reg, tmp; \
 88:     brnz,pt tmp, 88b; \
@@ -22,9 +25,11 @@
 #else
 
 #define BACKOFF_SETUP(reg)
-#define BACKOFF_SPIN(reg, tmp, label) \
-        ba,pt   %xcc, label; \
-         nop;
+
+#define BACKOFF_LABEL(spin_label, continue_label) \
+        continue_label
+
+#define BACKOFF_SPIN(reg, tmp, label)
 
 #endif