atomic.h (3569B)
1/* SPDX-License-Identifier: GPL-2.0-or-later */ 2/* 3 * Generic C implementation of atomic counter operations. Do not include in 4 * machine independent code. 5 * 6 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. 7 * Written by David Howells (dhowells@redhat.com) 8 */ 9#ifndef __ASM_GENERIC_ATOMIC_H 10#define __ASM_GENERIC_ATOMIC_H 11 12#include <asm/cmpxchg.h> 13#include <asm/barrier.h> 14 15#ifdef CONFIG_SMP 16 17/* we can build all atomic primitives from cmpxchg */ 18 19#define ATOMIC_OP(op, c_op) \ 20static inline void generic_atomic_##op(int i, atomic_t *v) \ 21{ \ 22 int c, old; \ 23 \ 24 c = v->counter; \ 25 while ((old = arch_cmpxchg(&v->counter, c, c c_op i)) != c) \ 26 c = old; \ 27} 28 29#define ATOMIC_OP_RETURN(op, c_op) \ 30static inline int generic_atomic_##op##_return(int i, atomic_t *v) \ 31{ \ 32 int c, old; \ 33 \ 34 c = v->counter; \ 35 while ((old = arch_cmpxchg(&v->counter, c, c c_op i)) != c) \ 36 c = old; \ 37 \ 38 return c c_op i; \ 39} 40 41#define ATOMIC_FETCH_OP(op, c_op) \ 42static inline int generic_atomic_fetch_##op(int i, atomic_t *v) \ 43{ \ 44 int c, old; \ 45 \ 46 c = v->counter; \ 47 while ((old = arch_cmpxchg(&v->counter, c, c c_op i)) != c) \ 48 c = old; \ 49 \ 50 return c; \ 51} 52 53#else 54 55#include <linux/irqflags.h> 56 57#define ATOMIC_OP(op, c_op) \ 58static inline void generic_atomic_##op(int i, atomic_t *v) \ 59{ \ 60 unsigned long flags; \ 61 \ 62 raw_local_irq_save(flags); \ 63 v->counter = v->counter c_op i; \ 64 raw_local_irq_restore(flags); \ 65} 66 67#define ATOMIC_OP_RETURN(op, c_op) \ 68static inline int generic_atomic_##op##_return(int i, atomic_t *v) \ 69{ \ 70 unsigned long flags; \ 71 int ret; \ 72 \ 73 raw_local_irq_save(flags); \ 74 ret = (v->counter = v->counter c_op i); \ 75 raw_local_irq_restore(flags); \ 76 \ 77 return ret; \ 78} 79 80#define ATOMIC_FETCH_OP(op, c_op) \ 81static inline int generic_atomic_fetch_##op(int i, atomic_t *v) \ 82{ \ 83 unsigned long flags; \ 84 int ret; \ 85 \ 86 raw_local_irq_save(flags); \ 87 ret = v->counter; \ 88 v->counter = v->counter c_op i; \ 89 raw_local_irq_restore(flags); \ 90 \ 91 return ret; \ 92} 93 94#endif /* CONFIG_SMP */ 95 96ATOMIC_OP_RETURN(add, +) 97ATOMIC_OP_RETURN(sub, -) 98 99ATOMIC_FETCH_OP(add, +) 100ATOMIC_FETCH_OP(sub, -) 101ATOMIC_FETCH_OP(and, &) 102ATOMIC_FETCH_OP(or, |) 103ATOMIC_FETCH_OP(xor, ^) 104 105ATOMIC_OP(add, +) 106ATOMIC_OP(sub, -) 107ATOMIC_OP(and, &) 108ATOMIC_OP(or, |) 109ATOMIC_OP(xor, ^) 110 111#undef ATOMIC_FETCH_OP 112#undef ATOMIC_OP_RETURN 113#undef ATOMIC_OP 114 115#define arch_atomic_add_return generic_atomic_add_return 116#define arch_atomic_sub_return generic_atomic_sub_return 117 118#define arch_atomic_fetch_add generic_atomic_fetch_add 119#define arch_atomic_fetch_sub generic_atomic_fetch_sub 120#define arch_atomic_fetch_and generic_atomic_fetch_and 121#define arch_atomic_fetch_or generic_atomic_fetch_or 122#define arch_atomic_fetch_xor generic_atomic_fetch_xor 123 124#define arch_atomic_add generic_atomic_add 125#define arch_atomic_sub generic_atomic_sub 126#define arch_atomic_and generic_atomic_and 127#define arch_atomic_or generic_atomic_or 128#define arch_atomic_xor generic_atomic_xor 129 130#define arch_atomic_read(v) READ_ONCE((v)->counter) 131#define arch_atomic_set(v, i) WRITE_ONCE(((v)->counter), (i)) 132 133#define arch_atomic_xchg(ptr, v) (arch_xchg(&(ptr)->counter, (v))) 134#define arch_atomic_cmpxchg(v, old, new) (arch_cmpxchg(&((v)->counter), (old), (new))) 135 136#endif /* __ASM_GENERIC_ATOMIC_H */