Commit 62c6081d authored by Paul Burton's avatar Paul Burton Committed by Ralf Baechle
Browse files

MIPS: cmpxchg: Drop __xchg_u{32,64} functions 



The __xchg_u32() & __xchg_u64() functions now add very little value.
This patch therefore removes them, by:

  - Moving memory barriers out of them & into xchg(), which also removes
    the duplication & readies us to support xchg_relaxed() if we wish to.

  - Calling __xchg_asm() directly from __xchg().

  - Performing the check for CONFIG_64BIT being enabled in the size=8
    case of __xchg().

Signed-off-by: default avatarPaul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16352/


Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
parent d15dc68c

arch/mips/include/asm/cmpxchg.h

+17 −31
Original line number Diff line number Diff line
@@ -70,40 +70,18 @@ extern unsigned long __xchg_called_with_bad_pointer(void) 
	__ret;								\

})



static inline unsigned long __xchg_u32(volatile int * m, unsigned int val)

{

	__u32 retval;



	smp_mb__before_llsc();

	retval = __xchg_asm("ll", "sc", m, val);

	smp_llsc_mb();



	return retval;

}



#ifdef CONFIG_64BIT

static inline __u64 __xchg_u64(volatile __u64 * m, __u64 val)

{

	__u64 retval;



	smp_mb__before_llsc();

	retval = __xchg_asm("lld", "scd", m, val);

	smp_llsc_mb();



	return retval;

}

#else

extern __u64 __xchg_u64_unsupported_on_32bit_kernels(volatile __u64 * m, __u64 val);

#define __xchg_u64 __xchg_u64_unsupported_on_32bit_kernels

#endif



static inline unsigned long __xchg(unsigned long x, volatile void * ptr, int size)

{

	switch (size) {

	case 4:

		return __xchg_u32(ptr, x);

		return __xchg_asm("ll", "sc", (volatile u32 *)ptr, x);



	case 8:

		return __xchg_u64(ptr, x);

		if (!IS_ENABLED(CONFIG_64BIT))

			return __xchg_called_with_bad_pointer();



		return __xchg_asm("lld", "scd", (volatile u64 *)ptr, x);



	default:

		return __xchg_called_with_bad_pointer();

	}
@@ -111,10 +89,18 @@ static inline unsigned long __xchg(unsigned long x, volatile void * ptr, int siz 


#define xchg(ptr, x)							\

({									\

	__typeof__(*(ptr)) __res;					\

									\

	BUILD_BUG_ON(sizeof(*(ptr)) & ~0xc);				\

									\

	((__typeof__(*(ptr)))						\

		__xchg((unsigned long)(x), (ptr), sizeof(*(ptr))));	\

	smp_mb__before_llsc();						\

									\

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

		__xchg((unsigned long)(x), (ptr), sizeof(*(ptr)));	\

									\

	smp_llsc_mb();							\

									\

	__res;								\

})



#define __cmpxchg_asm(ld, st, m, old, new)				\

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