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Commit 8aaf1dda authored by Chris Metcalf's avatar Chris Metcalf
Browse files

arch/tile: use better definitions of xchg() and cmpxchg() 



These definitions use a ({}) construct to avoid some cases where
we were getting warnings about unused return values.  We also
promote the definition to the common <asm/atomic.h>, since it applies
to both the 32- and 64-bit atomics.

In addition, define __HAVE_ARCH_CMPXCHG for TILE-Gx since it has
efficient direct atomic instructions.

Signed-off-by: default avatarChris Metcalf <cmetcalf@tilera.com>
parent 4800a5bb

arch/tile/include/asm/atomic.h

+42 −7
Original line number Diff line number Diff line
@@ -130,17 +130,52 @@ static inline int atomic_read(const atomic_t *v) 
 */

#define atomic_inc_not_zero(v)		atomic_add_unless((v), 1, 0)





/*

 * We define xchg() and cmpxchg() in the included headers.

 * Note that we do not define __HAVE_ARCH_CMPXCHG, since that would imply

 * that cmpxchg() is an efficient operation, which is not particularly true.

 */



/* Nonexistent functions intended to cause link errors. */

extern unsigned long __xchg_called_with_bad_pointer(void);

extern unsigned long __cmpxchg_called_with_bad_pointer(void);



#define xchg(ptr, x)							\

	({								\

		typeof(*(ptr)) __x;					\

		switch (sizeof(*(ptr))) {				\

		case 4:							\

			__x = (typeof(__x))(typeof(__x-__x))atomic_xchg( \

				(atomic_t *)(ptr),			\

				(u32)(typeof((x)-(x)))(x));		\

			break;						\

		case 8:							\

			__x = (typeof(__x))(typeof(__x-__x))atomic64_xchg( \

				(atomic64_t *)(ptr),			\

				(u64)(typeof((x)-(x)))(x));		\

			break;						\

		default:						\

			__xchg_called_with_bad_pointer();		\

		}							\

		__x;							\

	})



#define cmpxchg(ptr, o, n)						\

	({								\

		typeof(*(ptr)) __x;					\

		switch (sizeof(*(ptr))) {				\

		case 4:							\

			__x = (typeof(__x))(typeof(__x-__x))atomic_cmpxchg( \

				(atomic_t *)(ptr),			\

				(u32)(typeof((o)-(o)))(o),		\

				(u32)(typeof((n)-(n)))(n));		\

			break;						\

		case 8:							\

			__x = (typeof(__x))(typeof(__x-__x))atomic64_cmpxchg( \

				(atomic64_t *)(ptr),			\

				(u64)(typeof((o)-(o)))(o),		\

				(u64)(typeof((n)-(n)))(n));		\

			break;						\

		default:						\

			__cmpxchg_called_with_bad_pointer();		\

		}							\

		__x;							\

	})



#define tas(ptr) (xchg((ptr), 1))



#endif /* __ASSEMBLY__ */

arch/tile/include/asm/atomic_32.h

+0 −10
Original line number Diff line number Diff line
@@ -110,16 +110,6 @@ static inline void atomic_set(atomic_t *v, int n) 
	_atomic_xchg(v, n);

}



#define xchg(ptr, x) ((typeof(*(ptr))) \

  ((sizeof(*(ptr)) == sizeof(atomic_t)) ? \

   atomic_xchg((atomic_t *)(ptr), (long)(x)) : \

   __xchg_called_with_bad_pointer()))



#define cmpxchg(ptr, o, n) ((typeof(*(ptr))) \

  ((sizeof(*(ptr)) == sizeof(atomic_t)) ? \

   atomic_cmpxchg((atomic_t *)(ptr), (long)(o), (long)(n)) : \

   __cmpxchg_called_with_bad_pointer()))



/* A 64bit atomic type */



typedef struct {

arch/tile/include/asm/atomic_64.h

+2 −15
Original line number Diff line number Diff line
@@ -148,21 +148,8 @@ static inline long atomic64_add_unless(atomic64_t *v, long a, long u) 
#define smp_mb__before_atomic_inc()	smp_mb()

#define smp_mb__after_atomic_inc()	smp_mb()



#define xchg(ptr, x)							\

	((typeof(*(ptr)))						\

	 ((sizeof(*(ptr)) == sizeof(atomic_t)) ?			\

	  atomic_xchg((atomic_t *)(ptr), (long)(x)) :			\

	  (sizeof(*(ptr)) == sizeof(atomic_long_t)) ?			\

	  atomic_long_xchg((atomic_long_t *)(ptr), (long)(x)) :		\

	  __xchg_called_with_bad_pointer()))



#define cmpxchg(ptr, o, n)						\

	((typeof(*(ptr)))						\

	 ((sizeof(*(ptr)) == sizeof(atomic_t)) ?			\

	  atomic_cmpxchg((atomic_t *)(ptr), (long)(o), (long)(n)) :	\

	  (sizeof(*(ptr)) == sizeof(atomic_long_t)) ?			\

	  atomic_long_cmpxchg((atomic_long_t *)(ptr), (long)(o), (long)(n)) : \

	  __cmpxchg_called_with_bad_pointer()))

/* Define this to indicate that cmpxchg is an efficient operation. */

#define __HAVE_ARCH_CMPXCHG



#endif /* !__ASSEMBLY__ */