From 8aaf1dda42576b0f8dffb004065baa806f4df9b6 Mon Sep 17 00:00:00 2001 From: Chris Metcalf Date: Mon, 16 May 2011 13:59:39 -0400 Subject: 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 , 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: Chris Metcalf --- arch/tile/include/asm/atomic.h | 49 ++++++++++++++++++++++++++++++++++++------ 1 file changed, 42 insertions(+), 7 deletions(-) (limited to 'arch/tile/include/asm/atomic.h') diff --git a/arch/tile/include/asm/atomic.h b/arch/tile/include/asm/atomic.h index 75a1602..739cfe0 100644 --- a/arch/tile/include/asm/atomic.h +++ b/arch/tile/include/asm/atomic.h @@ -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__ */ -- cgit v1.1