Commit | Line | Data |
---|---|---|
3f7e212d | 1 | /* |
acac43e2 AS |
2 | * Generic C implementation of atomic counter operations. Usable on |
3 | * UP systems only. Do not include in machine independent code. | |
4 | * | |
3f7e212d AB |
5 | * Originally implemented for MN10300. |
6 | * | |
7 | * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. | |
8 | * Written by David Howells (dhowells@redhat.com) | |
9 | * | |
10 | * This program is free software; you can redistribute it and/or | |
11 | * modify it under the terms of the GNU General Public Licence | |
12 | * as published by the Free Software Foundation; either version | |
13 | * 2 of the Licence, or (at your option) any later version. | |
14 | */ | |
15 | #ifndef __ASM_GENERIC_ATOMIC_H | |
16 | #define __ASM_GENERIC_ATOMIC_H | |
17 | ||
34484277 | 18 | #include <asm/cmpxchg.h> |
febdbfe8 | 19 | #include <asm/barrier.h> |
34484277 | 20 | |
560cb12a PZ |
21 | /* |
22 | * atomic_$op() - $op integer to atomic variable | |
23 | * @i: integer value to $op | |
24 | * @v: pointer to the atomic variable | |
25 | * | |
26 | * Atomically $ops @i to @v. Does not strictly guarantee a memory-barrier, use | |
27 | * smp_mb__{before,after}_atomic(). | |
28 | */ | |
29 | ||
30 | /* | |
31 | * atomic_$op_return() - $op interer to atomic variable and returns the result | |
32 | * @i: integer value to $op | |
33 | * @v: pointer to the atomic variable | |
34 | * | |
35 | * Atomically $ops @i to @v. Does imply a full memory barrier. | |
36 | */ | |
37 | ||
3f7e212d | 38 | #ifdef CONFIG_SMP |
560cb12a PZ |
39 | |
40 | /* we can build all atomic primitives from cmpxchg */ | |
41 | ||
42 | #define ATOMIC_OP(op, c_op) \ | |
43 | static inline void atomic_##op(int i, atomic_t *v) \ | |
44 | { \ | |
45 | int c, old; \ | |
46 | \ | |
47 | c = v->counter; \ | |
48 | while ((old = cmpxchg(&v->counter, c, c c_op i)) != c) \ | |
49 | c = old; \ | |
50 | } | |
51 | ||
52 | #define ATOMIC_OP_RETURN(op, c_op) \ | |
53 | static inline int atomic_##op##_return(int i, atomic_t *v) \ | |
54 | { \ | |
55 | int c, old; \ | |
56 | \ | |
57 | c = v->counter; \ | |
58 | while ((old = cmpxchg(&v->counter, c, c c_op i)) != c) \ | |
59 | c = old; \ | |
60 | \ | |
61 | return c c_op i; \ | |
62 | } | |
63 | ||
64 | #else | |
65 | ||
66 | #include <linux/irqflags.h> | |
67 | ||
68 | #define ATOMIC_OP(op, c_op) \ | |
69 | static inline void atomic_##op(int i, atomic_t *v) \ | |
70 | { \ | |
71 | unsigned long flags; \ | |
72 | \ | |
73 | raw_local_irq_save(flags); \ | |
74 | v->counter = v->counter c_op i; \ | |
75 | raw_local_irq_restore(flags); \ | |
76 | } | |
77 | ||
78 | #define ATOMIC_OP_RETURN(op, c_op) \ | |
79 | static inline int atomic_##op##_return(int i, atomic_t *v) \ | |
80 | { \ | |
81 | unsigned long flags; \ | |
82 | int ret; \ | |
83 | \ | |
84 | raw_local_irq_save(flags); \ | |
85 | ret = (v->counter = v->counter c_op i); \ | |
86 | raw_local_irq_restore(flags); \ | |
87 | \ | |
88 | return ret; \ | |
89 | } | |
90 | ||
91 | #endif /* CONFIG_SMP */ | |
92 | ||
93 | #ifndef atomic_add_return | |
94 | ATOMIC_OP_RETURN(add, +) | |
95 | #endif | |
96 | ||
97 | #ifndef atomic_sub_return | |
98 | ATOMIC_OP_RETURN(sub, -) | |
99 | #endif | |
100 | ||
56d1defe | 101 | #ifndef atomic_and |
560cb12a | 102 | ATOMIC_OP(and, &) |
56d1defe PZ |
103 | #endif |
104 | ||
56d1defe | 105 | #ifndef atomic_or |
560cb12a | 106 | ATOMIC_OP(or, |) |
56d1defe PZ |
107 | #endif |
108 | ||
e6942b7d PZ |
109 | #ifndef atomic_xor |
110 | ATOMIC_OP(xor, ^) | |
560cb12a PZ |
111 | #endif |
112 | ||
113 | #undef ATOMIC_OP_RETURN | |
114 | #undef ATOMIC_OP | |
115 | ||
3f7e212d AB |
116 | /* |
117 | * Atomic operations that C can't guarantee us. Useful for | |
118 | * resource counting etc.. | |
119 | */ | |
120 | ||
121 | #define ATOMIC_INIT(i) { (i) } | |
122 | ||
3f7e212d AB |
123 | /** |
124 | * atomic_read - read atomic variable | |
125 | * @v: pointer of type atomic_t | |
126 | * | |
37682177 | 127 | * Atomically reads the value of @v. |
3f7e212d | 128 | */ |
7505cb60 | 129 | #ifndef atomic_read |
62e8a325 | 130 | #define atomic_read(v) READ_ONCE((v)->counter) |
7505cb60 | 131 | #endif |
3f7e212d AB |
132 | |
133 | /** | |
134 | * atomic_set - set atomic variable | |
135 | * @v: pointer of type atomic_t | |
136 | * @i: required value | |
137 | * | |
37682177 | 138 | * Atomically sets the value of @v to @i. |
3f7e212d | 139 | */ |
62e8a325 | 140 | #define atomic_set(v, i) WRITE_ONCE(((v)->counter), (i)) |
3f7e212d | 141 | |
df9ee292 | 142 | #include <linux/irqflags.h> |
3f7e212d | 143 | |
3f7e212d AB |
144 | static inline int atomic_add_negative(int i, atomic_t *v) |
145 | { | |
146 | return atomic_add_return(i, v) < 0; | |
147 | } | |
148 | ||
149 | static inline void atomic_add(int i, atomic_t *v) | |
150 | { | |
151 | atomic_add_return(i, v); | |
152 | } | |
153 | ||
154 | static inline void atomic_sub(int i, atomic_t *v) | |
155 | { | |
156 | atomic_sub_return(i, v); | |
157 | } | |
158 | ||
159 | static inline void atomic_inc(atomic_t *v) | |
160 | { | |
161 | atomic_add_return(1, v); | |
162 | } | |
163 | ||
164 | static inline void atomic_dec(atomic_t *v) | |
165 | { | |
166 | atomic_sub_return(1, v); | |
167 | } | |
168 | ||
169 | #define atomic_dec_return(v) atomic_sub_return(1, (v)) | |
170 | #define atomic_inc_return(v) atomic_add_return(1, (v)) | |
171 | ||
172 | #define atomic_sub_and_test(i, v) (atomic_sub_return((i), (v)) == 0) | |
3eea44ea MF |
173 | #define atomic_dec_and_test(v) (atomic_dec_return(v) == 0) |
174 | #define atomic_inc_and_test(v) (atomic_inc_return(v) == 0) | |
3f7e212d | 175 | |
8b9d4069 ML |
176 | #define atomic_xchg(ptr, v) (xchg(&(ptr)->counter, (v))) |
177 | #define atomic_cmpxchg(v, old, new) (cmpxchg(&((v)->counter), (old), (new))) | |
178 | ||
f24219b4 | 179 | static inline int __atomic_add_unless(atomic_t *v, int a, int u) |
8b9d4069 | 180 | { |
560cb12a PZ |
181 | int c, old; |
182 | c = atomic_read(v); | |
183 | while (c != u && (old = atomic_cmpxchg(v, c, c + a)) != c) | |
184 | c = old; | |
185 | return c; | |
3f7e212d | 186 | } |
00b3c28b | 187 | |
3f7e212d | 188 | #endif /* __ASM_GENERIC_ATOMIC_H */ |