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Diffstat (limited to 'include/linux/atomic.h')
| -rw-r--r-- | include/linux/atomic.h | 323 |
1 files changed, 323 insertions, 0 deletions
diff --git a/include/linux/atomic.h b/include/linux/atomic.h index 5b08a8540ecf..41ea776052be 100644 --- a/include/linux/atomic.h +++ b/include/linux/atomic.h @@ -2,6 +2,329 @@ #ifndef _LINUX_ATOMIC_H #define _LINUX_ATOMIC_H #include <asm/atomic.h> +#include <asm/barrier.h> + +/* + * Relaxed variants of xchg, cmpxchg and some atomic operations. + * + * We support four variants: + * + * - Fully ordered: The default implementation, no suffix required. + * - Acquire: Provides ACQUIRE semantics, _acquire suffix. + * - Release: Provides RELEASE semantics, _release suffix. + * - Relaxed: No ordering guarantees, _relaxed suffix. + * + * For compound atomics performing both a load and a store, ACQUIRE + * semantics apply only to the load and RELEASE semantics only to the + * store portion of the operation. Note that a failed cmpxchg_acquire + * does -not- imply any memory ordering constraints. + * + * See Documentation/memory-barriers.txt for ACQUIRE/RELEASE definitions. + */ + +#ifndef atomic_read_acquire +#define atomic_read_acquire(v) smp_load_acquire(&(v)->counter) +#endif + +#ifndef atomic_set_release +#define atomic_set_release(v, i) smp_store_release(&(v)->counter, (i)) +#endif + +/* + * The idea here is to build acquire/release variants by adding explicit + * barriers on top of the relaxed variant. In the case where the relaxed + * variant is already fully ordered, no additional barriers are needed. + */ +#define __atomic_op_acquire(op, args...) \ +({ \ + typeof(op##_relaxed(args)) __ret = op##_relaxed(args); \ + smp_mb__after_atomic(); \ + __ret; \ +}) + +#define __atomic_op_release(op, args...) \ +({ \ + smp_mb__before_atomic(); \ + op##_relaxed(args); \ +}) + +#define __atomic_op_fence(op, args...) \ +({ \ + typeof(op##_relaxed(args)) __ret; \ + smp_mb__before_atomic(); \ + __ret = op##_relaxed(args); \ + smp_mb__after_atomic(); \ + __ret; \ +}) + +/* atomic_add_return_relaxed */ +#ifndef atomic_add_return_relaxed +#define atomic_add_return_relaxed atomic_add_return +#define atomic_add_return_acquire atomic_add_return +#define atomic_add_return_release atomic_add_return + +#else /* atomic_add_return_relaxed */ + +#ifndef atomic_add_return_acquire +#define atomic_add_return_acquire(...) \ + __atomic_op_acquire(atomic_add_return, __VA_ARGS__) +#endif + +#ifndef atomic_add_return_release +#define atomic_add_return_release(...) \ + __atomic_op_release(atomic_add_return, __VA_ARGS__) +#endif + +#ifndef atomic_add_return +#define atomic_add_return(...) \ + __atomic_op_fence(atomic_add_return, __VA_ARGS__) +#endif +#endif /* atomic_add_return_relaxed */ + +/* atomic_sub_return_relaxed */ +#ifndef atomic_sub_return_relaxed +#define atomic_sub_return_relaxed atomic_sub_return +#define atomic_sub_return_acquire atomic_sub_return +#define atomic_sub_return_release atomic_sub_return + +#else /* atomic_sub_return_relaxed */ + +#ifndef atomic_sub_return_acquire +#define atomic_sub_return_acquire(...) \ + __atomic_op_acquire(atomic_sub_return, __VA_ARGS__) +#endif + +#ifndef atomic_sub_return_release +#define atomic_sub_return_release(...) \ + __atomic_op_release(atomic_sub_return, __VA_ARGS__) +#endif + +#ifndef atomic_sub_return +#define atomic_sub_return(...) \ + __atomic_op_fence(atomic_sub_return, __VA_ARGS__) +#endif +#endif /* atomic_sub_return_relaxed */ + +/* atomic_xchg_relaxed */ +#ifndef atomic_xchg_relaxed +#define atomic_xchg_relaxed atomic_xchg +#define atomic_xchg_acquire atomic_xchg +#define atomic_xchg_release atomic_xchg + +#else /* atomic_xchg_relaxed */ + +#ifndef atomic_xchg_acquire +#define atomic_xchg_acquire(...) \ + __atomic_op_acquire(atomic_xchg, __VA_ARGS__) +#endif + +#ifndef atomic_xchg_release +#define atomic_xchg_release(...) \ + __atomic_op_release(atomic_xchg, __VA_ARGS__) +#endif + +#ifndef atomic_xchg +#define atomic_xchg(...) \ + __atomic_op_fence(atomic_xchg, __VA_ARGS__) +#endif +#endif /* atomic_xchg_relaxed */ + +/* atomic_cmpxchg_relaxed */ +#ifndef atomic_cmpxchg_relaxed +#define atomic_cmpxchg_relaxed atomic_cmpxchg +#define atomic_cmpxchg_acquire atomic_cmpxchg +#define atomic_cmpxchg_release atomic_cmpxchg + +#else /* atomic_cmpxchg_relaxed */ + +#ifndef atomic_cmpxchg_acquire +#define atomic_cmpxchg_acquire(...) \ + __atomic_op_acquire(atomic_cmpxchg, __VA_ARGS__) +#endif + +#ifndef atomic_cmpxchg_release +#define atomic_cmpxchg_release(...) \ + __atomic_op_release(atomic_cmpxchg, __VA_ARGS__) +#endif + +#ifndef atomic_cmpxchg +#define atomic_cmpxchg(...) \ + __atomic_op_fence(atomic_cmpxchg, __VA_ARGS__) +#endif +#endif /* atomic_cmpxchg_relaxed */ + +#ifndef atomic64_read_acquire +#define atomic64_read_acquire(v) smp_load_acquire(&(v)->counter) +#endif + +#ifndef atomic64_set_release +#define atomic64_set_release(v, i) smp_store_release(&(v)->counter, (i)) +#endif + +/* atomic64_add_return_relaxed */ +#ifndef atomic64_add_return_relaxed +#define atomic64_add_return_relaxed atomic64_add_return +#define atomic64_add_return_acquire atomic64_add_return +#define atomic64_add_return_release atomic64_add_return + +#else /* atomic64_add_return_relaxed */ + +#ifndef atomic64_add_return_acquire +#define atomic64_add_return_acquire(...) \ + __atomic_op_acquire(atomic64_add_return, __VA_ARGS__) +#endif + +#ifndef atomic64_add_return_release +#define atomic64_add_return_release(...) \ + __atomic_op_release(atomic64_add_return, __VA_ARGS__) +#endif + +#ifndef atomic64_add_return +#define atomic64_add_return(...) \ + __atomic_op_fence(atomic64_add_return, __VA_ARGS__) +#endif +#endif /* atomic64_add_return_relaxed */ + +/* atomic64_sub_return_relaxed */ +#ifndef atomic64_sub_return_relaxed +#define atomic64_sub_return_relaxed atomic64_sub_return +#define atomic64_sub_return_acquire atomic64_sub_return +#define atomic64_sub_return_release atomic64_sub_return + +#else /* atomic64_sub_return_relaxed */ + +#ifndef atomic64_sub_return_acquire +#define atomic64_sub_return_acquire(...) \ + __atomic_op_acquire(atomic64_sub_return, __VA_ARGS__) +#endif + +#ifndef atomic64_sub_return_release +#define atomic64_sub_return_release(...) \ + __atomic_op_release(atomic64_sub_return, __VA_ARGS__) +#endif + +#ifndef atomic64_sub_return +#define atomic64_sub_return(...) \ + __atomic_op_fence(atomic64_sub_return, __VA_ARGS__) +#endif +#endif /* atomic64_sub_return_relaxed */ + +/* atomic64_xchg_relaxed */ +#ifndef atomic64_xchg_relaxed +#define atomic64_xchg_relaxed atomic64_xchg +#define atomic64_xchg_acquire atomic64_xchg +#define atomic64_xchg_release atomic64_xchg + +#else /* atomic64_xchg_relaxed */ + +#ifndef atomic64_xchg_acquire +#define atomic64_xchg_acquire(...) \ + __atomic_op_acquire(atomic64_xchg, __VA_ARGS__) +#endif + +#ifndef atomic64_xchg_release +#define atomic64_xchg_release(...) \ + __atomic_op_release(atomic64_xchg, __VA_ARGS__) +#endif + +#ifndef atomic64_xchg +#define atomic64_xchg(...) \ + __atomic_op_fence(atomic64_xchg, __VA_ARGS__) +#endif +#endif /* atomic64_xchg_relaxed */ + +/* atomic64_cmpxchg_relaxed */ +#ifndef atomic64_cmpxchg_relaxed +#define atomic64_cmpxchg_relaxed atomic64_cmpxchg +#define atomic64_cmpxchg_acquire atomic64_cmpxchg +#define atomic64_cmpxchg_release atomic64_cmpxchg + +#else /* atomic64_cmpxchg_relaxed */ + +#ifndef atomic64_cmpxchg_acquire +#define atomic64_cmpxchg_acquire(...) \ + __atomic_op_acquire(atomic64_cmpxchg, __VA_ARGS__) +#endif + +#ifndef atomic64_cmpxchg_release +#define atomic64_cmpxchg_release(...) \ + __atomic_op_release(atomic64_cmpxchg, __VA_ARGS__) +#endif + +#ifndef atomic64_cmpxchg +#define atomic64_cmpxchg(...) \ + __atomic_op_fence(atomic64_cmpxchg, __VA_ARGS__) +#endif +#endif /* atomic64_cmpxchg_relaxed */ + +/* cmpxchg_relaxed */ +#ifndef cmpxchg_relaxed +#define cmpxchg_relaxed cmpxchg +#define cmpxchg_acquire cmpxchg +#define cmpxchg_release cmpxchg + +#else /* cmpxchg_relaxed */ + +#ifndef cmpxchg_acquire +#define cmpxchg_acquire(...) \ + __atomic_op_acquire(cmpxchg, __VA_ARGS__) +#endif + +#ifndef cmpxchg_release +#define cmpxchg_release(...) \ + __atomic_op_release(cmpxchg, __VA_ARGS__) +#endif + +#ifndef cmpxchg +#define cmpxchg(...) \ + __atomic_op_fence(cmpxchg, __VA_ARGS__) +#endif +#endif /* cmpxchg_relaxed */ + +/* cmpxchg64_relaxed */ +#ifndef cmpxchg64_relaxed +#define cmpxchg64_relaxed cmpxchg64 +#define cmpxchg64_acquire cmpxchg64 +#define cmpxchg64_release cmpxchg64 + +#else /* cmpxchg64_relaxed */ + +#ifndef cmpxchg64_acquire +#define cmpxchg64_acquire(...) \ + __atomic_op_acquire(cmpxchg64, __VA_ARGS__) +#endif + +#ifndef cmpxchg64_release +#define cmpxchg64_release(...) \ + __atomic_op_release(cmpxchg64, __VA_ARGS__) +#endif + +#ifndef cmpxchg64 +#define cmpxchg64(...) \ + __atomic_op_fence(cmpxchg64, __VA_ARGS__) +#endif +#endif /* cmpxchg64_relaxed */ + +/* xchg_relaxed */ +#ifndef xchg_relaxed +#define xchg_relaxed xchg +#define xchg_acquire xchg +#define xchg_release xchg + +#else /* xchg_relaxed */ + +#ifndef xchg_acquire +#define xchg_acquire(...) __atomic_op_acquire(xchg, __VA_ARGS__) +#endif + +#ifndef xchg_release +#define xchg_release(...) __atomic_op_release(xchg, __VA_ARGS__) +#endif + +#ifndef xchg +#define xchg(...) __atomic_op_fence(xchg, __VA_ARGS__) +#endif +#endif /* xchg_relaxed */ /** * atomic_add_unless - add unless the number is already a given value |