Commit ddc348c4 authored by Vineet Gupta's avatar Vineet Gupta
Browse files

ARC: cmpxchg/xchg: implement relaxed variants (LLSC config only) 



It only makes sense to do this for the LLSC config

Acked-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarVineet Gupta <vgupta@kernel.org>
parent e188f333

arch/arc/include/asm/cmpxchg.h

+2 −9
Original line number Diff line number Diff line
@@ -38,7 +38,7 @@ 
	_prev;								\

})



#define arch_cmpxchg(ptr, old, new)				        \

#define arch_cmpxchg_relaxed(ptr, old, new)				\

({									\

	__typeof__(ptr) _p_ = (ptr);					\

	__typeof__(*(ptr)) _o_ = (old);					\
@@ -47,12 +47,7 @@ 
									\

	switch(sizeof((_p_))) {						\

	case 4:								\

	        /*							\

		 * Explicit full memory barrier needed before/after	\

	         */							\

		smp_mb();						\

		_prev_ = __cmpxchg(_p_, _o_, _n_);			\

		smp_mb();						\

		break;							\

	default:							\

		BUILD_BUG();						\
@@ -108,16 +103,14 @@ 
	_val_;		/* get old value */				\

})



#define arch_xchg(ptr, val)						\

#define arch_xchg_relaxed(ptr, val)					\

({									\

	__typeof__(ptr) _p_ = (ptr);					\

	__typeof__(*(ptr)) _val_ = (val);				\

									\

	switch(sizeof(*(_p_))) {					\

	case 4:								\

		smp_mb();						\

		_val_ = __xchg(_p_, _val_);				\

	        smp_mb();						\

		break;							\

	default:							\

		BUILD_BUG();						\