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 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) \
30 static 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) \
42 static 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) \
58 static 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) \
68 static 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) \
81 static 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
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 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 #endif /* __ASM_GENERIC_ATOMIC_H */
134
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