Commit 8263db4d authored by Paul Burton's avatar Paul Burton Committed by Ralf Baechle
Browse files

MIPS: cmpxchg: Implement __cmpxchg() as a function 



Replace the macro definition of __cmpxchg() with an inline function,
which is easier to read & modify. The cmpxchg() & cmpxchg_local() macros
are adjusted to call the new __cmpxchg() function.

Signed-off-by: default avatarPaul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16353/


Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
parent 62c6081d

arch/mips/include/asm/cmpxchg.h

+32 −27
Original line number Diff line number Diff line
@@ -34,7 +34,7 @@ 
 *

 * - Get an error at link-time due to the call to the missing function.

 */

extern void __cmpxchg_called_with_bad_pointer(void)

extern unsigned long __cmpxchg_called_with_bad_pointer(void)

	__compiletime_error("Bad argument size for cmpxchg");

extern unsigned long __xchg_called_with_bad_pointer(void)

	__compiletime_error("Bad argument size for xchg");
@@ -137,38 +137,43 @@ static inline unsigned long __xchg(unsigned long x, volatile void * ptr, int siz 
	__ret;								\

})



#define __cmpxchg(ptr, old, new, pre_barrier, post_barrier)		\

static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old,

				      unsigned long new, unsigned int size)

{

	switch (size) {

	case 4:

		return __cmpxchg_asm("ll", "sc", (volatile u32 *)ptr, old, new);



	case 8:

		/* lld/scd are only available for MIPS64 */

		if (!IS_ENABLED(CONFIG_64BIT))

			return __cmpxchg_called_with_bad_pointer();



		return __cmpxchg_asm("lld", "scd", (volatile u64 *)ptr, old, new);



	default:

		return __cmpxchg_called_with_bad_pointer();

	}

}



#define cmpxchg_local(ptr, old, new)					\

	((__typeof__(*(ptr)))						\

		__cmpxchg((ptr),					\

			  (unsigned long)(__typeof__(*(ptr)))(old),	\

			  (unsigned long)(__typeof__(*(ptr)))(new),	\

			  sizeof(*(ptr))))



#define cmpxchg(ptr, old, new)						\

({									\

	__typeof__(ptr) __ptr = (ptr);					\

	__typeof__(*(ptr)) __old = (old);				\

	__typeof__(*(ptr)) __new = (new);				\

	__typeof__(*(ptr)) __res = 0;					\

									\

	pre_barrier;							\

									\

	switch (sizeof(*(__ptr))) {					\

	case 4:								\

		__res = __cmpxchg_asm("ll", "sc", __ptr, __old, __new); \

		break;							\

	case 8:								\

		if (sizeof(long) == 8) {				\

			__res = __cmpxchg_asm("lld", "scd", __ptr,	\

					   __old, __new);		\

			break;						\

		}							\

	default:							\

		__cmpxchg_called_with_bad_pointer();			\

		break;							\

	}								\

	__typeof__(*(ptr)) __res;					\

									\

	post_barrier;							\

	smp_mb__before_llsc();						\

	__res = cmpxchg_local((ptr), (old), (new));			\

	smp_llsc_mb();							\

									\

	__res;								\

})



#define cmpxchg(ptr, old, new)		__cmpxchg(ptr, old, new, smp_mb__before_llsc(), smp_llsc_mb())

#define cmpxchg_local(ptr, old, new)	__cmpxchg(ptr, old, new, , )



#ifdef CONFIG_64BIT

#define cmpxchg64_local(ptr, o, n)					\

  ({									\

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