/* SPDX-License-Identifier: GPL-2.0 *//* Atomic operations usable in machine independent code */#ifndef _LINUX_ATOMIC_H#define _LINUX_ATOMIC_H#include <linux/types.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. */ #define atomic_cond_read_acquire(v, c) smp_cond_load_acquire(&(v)->counter, (c))#define atomic_cond_read_relaxed(v, c) smp_cond_load_relaxed(&(v)->counter, (c)) #define atomic64_cond_read_acquire(v, c) smp_cond_load_acquire(&(v)->counter, (c))#define atomic64_cond_read_relaxed(v, c) smp_cond_load_relaxed(&(v)->counter, (c)) /* * 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. * * If an architecture overrides __atomic_acquire_fence() it will probably * want to define smp_mb__after_spinlock(). */#ifndef __atomic_acquire_fence#define __atomic_acquire_fence		smp_mb__after_atomic#endif #ifndef __atomic_release_fence#define __atomic_release_fence		smp_mb__before_atomic#endif #ifndef __atomic_pre_full_fence#define __atomic_pre_full_fence		smp_mb__before_atomic#endif #ifndef __atomic_post_full_fence#define __atomic_post_full_fence	smp_mb__after_atomic#endif #define __atomic_op_acquire(op, args...)				\({									\	typeof(op##_relaxed(args)) __ret  = op##_relaxed(args);		\	__atomic_acquire_fence();					\	__ret;								\}) #define __atomic_op_release(op, args...)				\({									\	__atomic_release_fence();					\	op##_relaxed(args);						\}) #define __atomic_op_fence(op, args...)					\({									\	typeof(op##_relaxed(args)) __ret;				\	__atomic_pre_full_fence();					\	__ret = op##_relaxed(args);					\	__atomic_post_full_fence();					\	__ret;								\}) #include <linux/atomic/atomic-arch-fallback.h>#include <linux/atomic/atomic-long.h>#include <linux/atomic/atomic-instrumented.h> #endif /* _LINUX_ATOMIC_H */