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) \ 20 static inline void atomic_##op(int i, atomic_t *v) \ 21 { \ 22 int c, old; \ 23 \ 24 c = v->counter; \ 25 while ((old = cmpxchg(&v->counter, c, c c_op i)) != c) \ 26 c = old; \ 27 } 28 29 #define ATOMIC_OP_RETURN(op, c_op) \ 30 static inline int atomic_##op##_return(int i, atomic_t *v) \ 31 { \ 32 int c, old; \ 33 \ 34 c = v->counter; \ 35 while ((old = 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) \ 42 static inline int atomic_fetch_##op(int i, atomic_t *v) \ 43 { \ 44 int c, old; \ 45 \ 46 c = v->counter; \ 47 while ((old = 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) \ 58 static inline void 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) \ 68 static inline int 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) \ 81 static inline int 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 96 ATOMIC_OP_RETURN(add, +) 97 ATOMIC_OP_RETURN(sub, -) 98 99 ATOMIC_FETCH_OP(add, +) 100 ATOMIC_FETCH_OP(sub, -) 101 ATOMIC_FETCH_OP(and, &) 102 ATOMIC_FETCH_OP(or, |) 103 ATOMIC_FETCH_OP(xor, ^) 104 105 ATOMIC_OP(add, +) 106 ATOMIC_OP(sub, -) 107 ATOMIC_OP(and, &) 108 ATOMIC_OP(or, |) 109 ATOMIC_OP(xor, ^) 110 111 #undef ATOMIC_FETCH_OP 112 #undef ATOMIC_OP_RETURN 113 #undef ATOMIC_OP 114 115 #define atomic_read(v) READ_ONCE((v)->counter) 116 #define atomic_set(v, i) WRITE_ONCE(((v)->counter), (i)) 117 118 #define atomic_xchg(ptr, v) (xchg(&(ptr)->counter, (v))) 119 #define atomic_cmpxchg(v, old, new) (cmpxchg(&((v)->counter), (old), (new))) 120 121 #endif /* __ASM_GENERIC_ATOMIC_H */ 122