[PATCH] ARC: cpu_relax() to be compiler barrier even for UP

[Vineet Gupta]

cpu_relax() on ARC has been barrier only for SMP (and no-op for UP). Per
recent discussions, it is safer to make it a compiler barrier
unconditionally.

Link: http://lkml.kernel.org/r/53A7D3AA.9020100@xxxxxxxxxxxx
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Signed-off-by: Vineet Gupta <vgupta@xxxxxxxxxxxx>
---
 arch/arc/include/asm/processor.h | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/arch/arc/include/asm/processor.h b/arch/arc/include/asm/processor.h
index 44545354e9e8..1d694c1ef6d6 100644
--- a/arch/arc/include/asm/processor.h
+++ b/arch/arc/include/asm/processor.h
@@ -57,11 +57,7 @@ struct task_struct;
  * A lot of busy-wait loops in SMP are based off of non-volatile data otherwise
  * get optimised away by gcc
  */
-#ifdef CONFIG_SMP
 #define cpu_relax()	__asm__ __volatile__ ("" : : : "memory")
-#else
-#define cpu_relax()	do { } while (0)
-#endif

 #define cpu_relax_lowlatency() cpu_relax()

-- 
1.9.1

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