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kernel
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linux
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>
+44
-32
+42
-7
arch/tile/include/asm/atomic.h
+42
-7
arch/tile/include/asm/atomic.h
···
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*/
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#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
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-
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/*
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* We define xchg() and cmpxchg() in the included headers.
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* Note that we do not define __HAVE_ARCH_CMPXCHG, since that would imply
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* that cmpxchg() is an efficient operation, which is not particularly true.
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*/
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-
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/* Nonexistent functions intended to cause link errors. */
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extern unsigned long __xchg_called_with_bad_pointer(void);
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extern unsigned long __cmpxchg_called_with_bad_pointer(void);
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+
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#define xchg(ptr, x) \
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({ \
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typeof(*(ptr)) __x; \
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switch (sizeof(*(ptr))) { \
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case 4: \
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__x = (typeof(__x))(typeof(__x-__x))atomic_xchg( \
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(atomic_t *)(ptr), \
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(u32)(typeof((x)-(x)))(x)); \
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break; \
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case 8: \
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__x = (typeof(__x))(typeof(__x-__x))atomic64_xchg( \
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(atomic64_t *)(ptr), \
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(u64)(typeof((x)-(x)))(x)); \
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break; \
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default: \
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__xchg_called_with_bad_pointer(); \
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} \
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__x; \
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})
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+
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#define cmpxchg(ptr, o, n) \
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({ \
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typeof(*(ptr)) __x; \
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switch (sizeof(*(ptr))) { \
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case 4: \
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__x = (typeof(__x))(typeof(__x-__x))atomic_cmpxchg( \
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(atomic_t *)(ptr), \
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(u32)(typeof((o)-(o)))(o), \
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(u32)(typeof((n)-(n)))(n)); \
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break; \
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case 8: \
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__x = (typeof(__x))(typeof(__x-__x))atomic64_cmpxchg( \
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(atomic64_t *)(ptr), \
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(u64)(typeof((o)-(o)))(o), \
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(u64)(typeof((n)-(n)))(n)); \
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break; \
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default: \
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__cmpxchg_called_with_bad_pointer(); \
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} \
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__x; \
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})
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#define tas(ptr) (xchg((ptr), 1))
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-10
arch/tile/include/asm/atomic_32.h
-10
arch/tile/include/asm/atomic_32.h
···
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_atomic_xchg(v, n);
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}
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#define xchg(ptr, x) ((typeof(*(ptr))) \
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((sizeof(*(ptr)) == sizeof(atomic_t)) ? \
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atomic_xchg((atomic_t *)(ptr), (long)(x)) : \
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__xchg_called_with_bad_pointer()))
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#define cmpxchg(ptr, o, n) ((typeof(*(ptr))) \
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((sizeof(*(ptr)) == sizeof(atomic_t)) ? \
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atomic_cmpxchg((atomic_t *)(ptr), (long)(o), (long)(n)) : \
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__cmpxchg_called_with_bad_pointer()))
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-
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/* A 64bit atomic type */
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typedef struct {
+2
-15
arch/tile/include/asm/atomic_64.h
+2
-15
arch/tile/include/asm/atomic_64.h
···
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#define smp_mb__before_atomic_inc() smp_mb()
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#define smp_mb__after_atomic_inc() smp_mb()
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#define xchg(ptr, x) \
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((typeof(*(ptr))) \
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((sizeof(*(ptr)) == sizeof(atomic_t)) ? \
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atomic_xchg((atomic_t *)(ptr), (long)(x)) : \
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(sizeof(*(ptr)) == sizeof(atomic_long_t)) ? \
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atomic_long_xchg((atomic_long_t *)(ptr), (long)(x)) : \
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__xchg_called_with_bad_pointer()))
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-
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#define cmpxchg(ptr, o, n) \
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((typeof(*(ptr))) \
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((sizeof(*(ptr)) == sizeof(atomic_t)) ? \
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atomic_cmpxchg((atomic_t *)(ptr), (long)(o), (long)(n)) : \
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(sizeof(*(ptr)) == sizeof(atomic_long_t)) ? \
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atomic_long_cmpxchg((atomic_long_t *)(ptr), (long)(o), (long)(n)) : \
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__cmpxchg_called_with_bad_pointer()))
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/* Define this to indicate that cmpxchg is an efficient operation. */
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#define __HAVE_ARCH_CMPXCHG
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#endif /* !__ASSEMBLY__ */
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