locking/x86: Define arch_try_cmpxchg_local()

Define target specific arch_try_cmpxchg_local(). This
definition overrides the generic arch_try_cmpxchg_local()
fallback definition and enables target-specific
implementation of try_cmpxchg_local().

Signed-off-by: Uros Bizjak <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Cc: Linus Torvalds <[email protected]>

Author: ubizjak

arch/x86/include/asm/cmpxchg.h

@@ -221,9 +221,15 @@ extern void __add_wrong_size(void)
 #define __try_cmpxchg(ptr, pold, new, size)				\
 	__raw_try_cmpxchg((ptr), (pold), (new), (size), LOCK_PREFIX)
 
+#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_try_cmpxchg_local(ptr, pold, new)				\
+	__try_cmpxchg_local((ptr), (pold), (new), sizeof(*(ptr)))
+
 /*
  * xadd() adds "inc" to "*ptr" and atomically returns the previous
  * value of "*ptr".