/* SPDX-License-Identifier: GPL-2.0 */ #ifndef _TOOLS_LINUX_ASM_X86_ATOMIC_H #define _TOOLS_LINUX_ASM_X86_ATOMIC_H #include <linux/compiler.h> #include <linux/types.h> #include "rmwcc.h" #define LOCK_PREFIX "\n\tlock; " #include <asm/cmpxchg.h> /* * Atomic operations that C can't guarantee us. Useful for * resource counting etc.. */ #define ATOMIC_INIT(i) { (i) } /** * atomic_read - read atomic variable * @v: pointer of type atomic_t * * Atomically reads the value of @v. */ static inline int atomic_read(const atomic_t *v) { return READ_ONCE((v)->counter); } /** * atomic_set - set atomic variable * @v: pointer of type atomic_t * @i: required value * * Atomically sets the value of @v to @i. */ static inline void atomic_set(atomic_t *v, int i) { v->counter = i; } /** * atomic_inc - increment atomic variable * @v: pointer of type atomic_t * * Atomically increments @v by 1. */ static inline void atomic_inc(atomic_t *v) { asm volatile(LOCK_PREFIX "incl %0" : "+m" (v->counter)); } /** * atomic_dec_and_test - decrement and test * @v: pointer of type atomic_t * * Atomically decrements @v by 1 and * returns true if the result is 0, or false for all other * cases. */ static inline int atomic_dec_and_test(atomic_t *v) { GEN_UNARY_RMWcc(LOCK_PREFIX "decl", v->counter, "%0", "e"); } static __always_inline int atomic_cmpxchg(atomic_t *v, int old, int new) { return cmpxchg(&v->counter, old, new); } #endif /* _TOOLS_LINUX_ASM_X86_ATOMIC_H */