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: Chris Metcalf <cmetcalf@tilera.com>
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 @@
*/
#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__ */
diff --git a/arch/tile/include/asm/atomic_32.h b/arch/tile/include/asm/atomic_32.h
index ed359ae..92a8bee 100644
--- a/arch/tile/include/asm/atomic_32.h
+++ b/arch/tile/include/asm/atomic_32.h
@@ -110,16 +110,6 @@
_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 {
diff --git a/arch/tile/include/asm/atomic_64.h b/arch/tile/include/asm/atomic_64.h
index 3217052..1c1e60d 100644
--- a/arch/tile/include/asm/atomic_64.h
+++ b/arch/tile/include/asm/atomic_64.h
@@ -148,21 +148,8 @@
#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__ */