From 02bfde5587941bd3fa4ead5d5884063d9a93c9ff Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Sun, 28 Aug 2011 10:35:59 -0700 Subject: [PATCH] powerpc: Strengthen value-returning-atomics memory barriers The trailing isync/lwsync in PowerPC value-returning atomics needs to be a sync in order to provide the required ordering properties. The leading lwsync/eieio can remain, as the remainder of the required ordering guarantees are provided by the atomic instructions: Any reordering will cause the stwcx to fail, which will result in a retry. This commit provides the needed adjustment. Signed-off-by: Paul E. McKenney Cc: anton@samba.org Cc: benh@kernel.crashing.org Cc: paulus@samba.org --- arch/powerpc/include/asm/synch.h | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) diff --git a/arch/powerpc/include/asm/synch.h b/arch/powerpc/include/asm/synch.h index d7cab44643c5..4d97fbeee74d 100644 --- a/arch/powerpc/include/asm/synch.h +++ b/arch/powerpc/include/asm/synch.h @@ -37,11 +37,7 @@ static inline void isync(void) #endif #ifdef CONFIG_SMP -#define __PPC_ACQUIRE_BARRIER \ - START_LWSYNC_SECTION(97); \ - isync; \ - MAKE_LWSYNC_SECTION_ENTRY(97, __lwsync_fixup); -#define PPC_ACQUIRE_BARRIER "\n" stringify_in_c(__PPC_ACQUIRE_BARRIER) +#define PPC_ACQUIRE_BARRIER "\n" stringify_in_c(sync;) #define PPC_RELEASE_BARRIER stringify_in_c(LWSYNC) "\n" #else #define PPC_ACQUIRE_BARRIER -- 2.39.5