[RESEND PATCH 2/2] locking/x86: Wire up sync_try_cmpxchg

[Uros Bizjak <ubizjak@gmail.com>]

Implement target specific support for sync_try_cmpxchg.

Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
---
 arch/x86/include/asm/cmpxchg.h | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/x86/include/asm/cmpxchg.h b/arch/x86/include/asm/cmpxchg.h
index d53636506134..5612648b0202 100644
--- a/arch/x86/include/asm/cmpxchg.h
+++ b/arch/x86/include/asm/cmpxchg.h
@@ -221,12 +221,18 @@ extern void __add_wrong_size(void)
 #define __try_cmpxchg(ptr, pold, new, size)				\
 	__raw_try_cmpxchg((ptr), (pold), (new), (size), LOCK_PREFIX)
 
+#define __sync_try_cmpxchg(ptr, pold, new, size)			\
+	__raw_try_cmpxchg((ptr), (pold), (new), (size), "lock; ")
+
 #define __try_cmpxchg_local(ptr, pold, new, size)			\
 	__raw_try_cmpxchg((ptr), (pold), (new), (size), "")
 
 #define arch_try_cmpxchg(ptr, pold, new) 				\
 	__try_cmpxchg((ptr), (pold), (new), sizeof(*(ptr)))
 
+#define arch_sync_try_cmpxchg(ptr, pold, new) 				\
+	__sync_try_cmpxchg((ptr), (pold), (new), sizeof(*(ptr)))
+
 #define arch_try_cmpxchg_local(ptr, pold, new)				\
 	__try_cmpxchg_local((ptr), (pold), (new), sizeof(*(ptr)))
 
-- 
2.41.0