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 | ||
18 | #ifdef CONFIG_SMP | |
7505cb60 MF |
19 | /* Force people to define core atomics */ |
20 | # if !defined(atomic_add_return) || !defined(atomic_sub_return) || \ | |
21 | !defined(atomic_clear_mask) || !defined(atomic_set_mask) | |
22 | # error "SMP requires a little arch-specific magic" | |
23 | # endif | |
3f7e212d AB |
24 | #endif |
25 | ||
26 | /* | |
27 | * Atomic operations that C can't guarantee us. Useful for | |
28 | * resource counting etc.. | |
29 | */ | |
30 | ||
31 | #define ATOMIC_INIT(i) { (i) } | |
32 | ||
33 | #ifdef __KERNEL__ | |
34 | ||
35 | /** | |
36 | * atomic_read - read atomic variable | |
37 | * @v: pointer of type atomic_t | |
38 | * | |
37682177 | 39 | * Atomically reads the value of @v. |
3f7e212d | 40 | */ |
7505cb60 | 41 | #ifndef atomic_read |
f3d46f9d | 42 | #define atomic_read(v) (*(volatile int *)&(v)->counter) |
7505cb60 | 43 | #endif |
3f7e212d AB |
44 | |
45 | /** | |
46 | * atomic_set - set atomic variable | |
47 | * @v: pointer of type atomic_t | |
48 | * @i: required value | |
49 | * | |
37682177 | 50 | * Atomically sets the value of @v to @i. |
3f7e212d AB |
51 | */ |
52 | #define atomic_set(v, i) (((v)->counter) = (i)) | |
53 | ||
df9ee292 | 54 | #include <linux/irqflags.h> |
3f7e212d AB |
55 | #include <asm/system.h> |
56 | ||
57 | /** | |
58 | * atomic_add_return - add integer to atomic variable | |
59 | * @i: integer value to add | |
60 | * @v: pointer of type atomic_t | |
61 | * | |
62 | * Atomically adds @i to @v and returns the result | |
3f7e212d | 63 | */ |
7505cb60 | 64 | #ifndef atomic_add_return |
3f7e212d AB |
65 | static inline int atomic_add_return(int i, atomic_t *v) |
66 | { | |
67 | unsigned long flags; | |
68 | int temp; | |
69 | ||
df9ee292 | 70 | raw_local_irq_save(flags); /* Don't trace it in an irqsoff handler */ |
3f7e212d AB |
71 | temp = v->counter; |
72 | temp += i; | |
73 | v->counter = temp; | |
9e58143d | 74 | raw_local_irq_restore(flags); |
3f7e212d AB |
75 | |
76 | return temp; | |
77 | } | |
7505cb60 | 78 | #endif |
3f7e212d AB |
79 | |
80 | /** | |
81 | * atomic_sub_return - subtract integer from atomic variable | |
82 | * @i: integer value to subtract | |
83 | * @v: pointer of type atomic_t | |
84 | * | |
85 | * Atomically subtracts @i from @v and returns the result | |
3f7e212d | 86 | */ |
7505cb60 | 87 | #ifndef atomic_sub_return |
3f7e212d AB |
88 | static inline int atomic_sub_return(int i, atomic_t *v) |
89 | { | |
90 | unsigned long flags; | |
91 | int temp; | |
92 | ||
df9ee292 | 93 | raw_local_irq_save(flags); /* Don't trace it in an irqsoff handler */ |
3f7e212d AB |
94 | temp = v->counter; |
95 | temp -= i; | |
96 | v->counter = temp; | |
9e58143d | 97 | raw_local_irq_restore(flags); |
3f7e212d AB |
98 | |
99 | return temp; | |
100 | } | |
7505cb60 | 101 | #endif |
3f7e212d AB |
102 | |
103 | static inline int atomic_add_negative(int i, atomic_t *v) | |
104 | { | |
105 | return atomic_add_return(i, v) < 0; | |
106 | } | |
107 | ||
108 | static inline void atomic_add(int i, atomic_t *v) | |
109 | { | |
110 | atomic_add_return(i, v); | |
111 | } | |
112 | ||
113 | static inline void atomic_sub(int i, atomic_t *v) | |
114 | { | |
115 | atomic_sub_return(i, v); | |
116 | } | |
117 | ||
118 | static inline void atomic_inc(atomic_t *v) | |
119 | { | |
120 | atomic_add_return(1, v); | |
121 | } | |
122 | ||
123 | static inline void atomic_dec(atomic_t *v) | |
124 | { | |
125 | atomic_sub_return(1, v); | |
126 | } | |
127 | ||
128 | #define atomic_dec_return(v) atomic_sub_return(1, (v)) | |
129 | #define atomic_inc_return(v) atomic_add_return(1, (v)) | |
130 | ||
131 | #define atomic_sub_and_test(i, v) (atomic_sub_return((i), (v)) == 0) | |
3eea44ea MF |
132 | #define atomic_dec_and_test(v) (atomic_dec_return(v) == 0) |
133 | #define atomic_inc_and_test(v) (atomic_inc_return(v) == 0) | |
3f7e212d | 134 | |
8b9d4069 ML |
135 | #define atomic_xchg(ptr, v) (xchg(&(ptr)->counter, (v))) |
136 | #define atomic_cmpxchg(v, old, new) (cmpxchg(&((v)->counter), (old), (new))) | |
137 | ||
138 | #define cmpxchg_local(ptr, o, n) \ | |
139 | ((__typeof__(*(ptr)))__cmpxchg_local_generic((ptr), (unsigned long)(o),\ | |
140 | (unsigned long)(n), sizeof(*(ptr)))) | |
141 | ||
142 | #define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n)) | |
143 | ||
f24219b4 | 144 | static inline int __atomic_add_unless(atomic_t *v, int a, int u) |
8b9d4069 ML |
145 | { |
146 | int c, old; | |
147 | c = atomic_read(v); | |
148 | while (c != u && (old = atomic_cmpxchg(v, c, c + a)) != c) | |
149 | c = old; | |
f24219b4 | 150 | return c; |
8b9d4069 | 151 | } |
3f7e212d | 152 | |
f6081bd3 MF |
153 | /** |
154 | * atomic_clear_mask - Atomically clear bits in atomic variable | |
155 | * @mask: Mask of the bits to be cleared | |
156 | * @v: pointer of type atomic_t | |
157 | * | |
158 | * Atomically clears the bits set in @mask from @v | |
159 | */ | |
7505cb60 | 160 | #ifndef atomic_clear_mask |
f6081bd3 | 161 | static inline void atomic_clear_mask(unsigned long mask, atomic_t *v) |
3f7e212d AB |
162 | { |
163 | unsigned long flags; | |
164 | ||
165 | mask = ~mask; | |
9e58143d | 166 | raw_local_irq_save(flags); /* Don't trace it in a irqsoff handler */ |
f6081bd3 | 167 | v->counter &= mask; |
9e58143d | 168 | raw_local_irq_restore(flags); |
3f7e212d | 169 | } |
7505cb60 | 170 | #endif |
3f7e212d | 171 | |
00b3c28b MF |
172 | /** |
173 | * atomic_set_mask - Atomically set bits in atomic variable | |
174 | * @mask: Mask of the bits to be set | |
175 | * @v: pointer of type atomic_t | |
176 | * | |
177 | * Atomically sets the bits set in @mask in @v | |
178 | */ | |
7505cb60 | 179 | #ifndef atomic_set_mask |
00b3c28b MF |
180 | static inline void atomic_set_mask(unsigned int mask, atomic_t *v) |
181 | { | |
182 | unsigned long flags; | |
183 | ||
184 | raw_local_irq_save(flags); /* Don't trace it in a irqsoff handler */ | |
185 | v->counter |= mask; | |
186 | raw_local_irq_restore(flags); | |
187 | } | |
7505cb60 | 188 | #endif |
00b3c28b | 189 | |
3f7e212d AB |
190 | /* Assume that atomic operations are already serializing */ |
191 | #define smp_mb__before_atomic_dec() barrier() | |
192 | #define smp_mb__after_atomic_dec() barrier() | |
193 | #define smp_mb__before_atomic_inc() barrier() | |
194 | #define smp_mb__after_atomic_inc() barrier() | |
195 | ||
3f7e212d AB |
196 | #endif /* __KERNEL__ */ |
197 | #endif /* __ASM_GENERIC_ATOMIC_H */ |