Merge branch 'for-4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
[linux-2.6-microblaze.git] / include / asm-generic / atomic.h
1 /*
2  * Generic C implementation of atomic counter operations. Usable on
3  * UP systems only. Do not include in machine independent code.
4  *
5  * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
6  * Written by David Howells (dhowells@redhat.com)
7  *
8  * This program is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU General Public Licence
10  * as published by the Free Software Foundation; either version
11  * 2 of the Licence, or (at your option) any later version.
12  */
13 #ifndef __ASM_GENERIC_ATOMIC_H
14 #define __ASM_GENERIC_ATOMIC_H
15
16 #include <asm/cmpxchg.h>
17 #include <asm/barrier.h>
18
19 /*
20  * atomic_$op() - $op integer to atomic variable
21  * @i: integer value to $op
22  * @v: pointer to the atomic variable
23  *
24  * Atomically $ops @i to @v. Does not strictly guarantee a memory-barrier, use
25  * smp_mb__{before,after}_atomic().
26  */
27
28 /*
29  * atomic_$op_return() - $op interer to atomic variable and returns the result
30  * @i: integer value to $op
31  * @v: pointer to the atomic variable
32  *
33  * Atomically $ops @i to @v. Does imply a full memory barrier.
34  */
35
36 #ifdef CONFIG_SMP
37
38 /* we can build all atomic primitives from cmpxchg */
39
40 #define ATOMIC_OP(op, c_op)                                             \
41 static inline void atomic_##op(int i, atomic_t *v)                      \
42 {                                                                       \
43         int c, old;                                                     \
44                                                                         \
45         c = v->counter;                                                 \
46         while ((old = cmpxchg(&v->counter, c, c c_op i)) != c)          \
47                 c = old;                                                \
48 }
49
50 #define ATOMIC_OP_RETURN(op, c_op)                                      \
51 static inline int atomic_##op##_return(int i, atomic_t *v)              \
52 {                                                                       \
53         int c, old;                                                     \
54                                                                         \
55         c = v->counter;                                                 \
56         while ((old = cmpxchg(&v->counter, c, c c_op i)) != c)          \
57                 c = old;                                                \
58                                                                         \
59         return c c_op i;                                                \
60 }
61
62 #define ATOMIC_FETCH_OP(op, c_op)                                       \
63 static inline int atomic_fetch_##op(int i, atomic_t *v)                 \
64 {                                                                       \
65         int c, old;                                                     \
66                                                                         \
67         c = v->counter;                                                 \
68         while ((old = cmpxchg(&v->counter, c, c c_op i)) != c)          \
69                 c = old;                                                \
70                                                                         \
71         return c;                                                       \
72 }
73
74 #else
75
76 #include <linux/irqflags.h>
77
78 #define ATOMIC_OP(op, c_op)                                             \
79 static inline void atomic_##op(int i, atomic_t *v)                      \
80 {                                                                       \
81         unsigned long flags;                                            \
82                                                                         \
83         raw_local_irq_save(flags);                                      \
84         v->counter = v->counter c_op i;                                 \
85         raw_local_irq_restore(flags);                                   \
86 }
87
88 #define ATOMIC_OP_RETURN(op, c_op)                                      \
89 static inline int atomic_##op##_return(int i, atomic_t *v)              \
90 {                                                                       \
91         unsigned long flags;                                            \
92         int ret;                                                        \
93                                                                         \
94         raw_local_irq_save(flags);                                      \
95         ret = (v->counter = v->counter c_op i);                         \
96         raw_local_irq_restore(flags);                                   \
97                                                                         \
98         return ret;                                                     \
99 }
100
101 #define ATOMIC_FETCH_OP(op, c_op)                                       \
102 static inline int atomic_fetch_##op(int i, atomic_t *v)                 \
103 {                                                                       \
104         unsigned long flags;                                            \
105         int ret;                                                        \
106                                                                         \
107         raw_local_irq_save(flags);                                      \
108         ret = v->counter;                                               \
109         v->counter = v->counter c_op i;                                 \
110         raw_local_irq_restore(flags);                                   \
111                                                                         \
112         return ret;                                                     \
113 }
114
115 #endif /* CONFIG_SMP */
116
117 #ifndef atomic_add_return
118 ATOMIC_OP_RETURN(add, +)
119 #endif
120
121 #ifndef atomic_sub_return
122 ATOMIC_OP_RETURN(sub, -)
123 #endif
124
125 #ifndef atomic_fetch_add
126 ATOMIC_FETCH_OP(add, +)
127 #endif
128
129 #ifndef atomic_fetch_sub
130 ATOMIC_FETCH_OP(sub, -)
131 #endif
132
133 #ifndef atomic_fetch_and
134 ATOMIC_FETCH_OP(and, &)
135 #endif
136
137 #ifndef atomic_fetch_or
138 ATOMIC_FETCH_OP(or, |)
139 #endif
140
141 #ifndef atomic_fetch_xor
142 ATOMIC_FETCH_OP(xor, ^)
143 #endif
144
145 #ifndef atomic_and
146 ATOMIC_OP(and, &)
147 #endif
148
149 #ifndef atomic_or
150 ATOMIC_OP(or, |)
151 #endif
152
153 #ifndef atomic_xor
154 ATOMIC_OP(xor, ^)
155 #endif
156
157 #undef ATOMIC_FETCH_OP
158 #undef ATOMIC_OP_RETURN
159 #undef ATOMIC_OP
160
161 /*
162  * Atomic operations that C can't guarantee us.  Useful for
163  * resource counting etc..
164  */
165
166 #define ATOMIC_INIT(i)  { (i) }
167
168 /**
169  * atomic_read - read atomic variable
170  * @v: pointer of type atomic_t
171  *
172  * Atomically reads the value of @v.
173  */
174 #ifndef atomic_read
175 #define atomic_read(v)  READ_ONCE((v)->counter)
176 #endif
177
178 /**
179  * atomic_set - set atomic variable
180  * @v: pointer of type atomic_t
181  * @i: required value
182  *
183  * Atomically sets the value of @v to @i.
184  */
185 #define atomic_set(v, i) WRITE_ONCE(((v)->counter), (i))
186
187 #include <linux/irqflags.h>
188
189 static inline void atomic_add(int i, atomic_t *v)
190 {
191         atomic_add_return(i, v);
192 }
193
194 static inline void atomic_sub(int i, atomic_t *v)
195 {
196         atomic_sub_return(i, v);
197 }
198
199 #define atomic_xchg(ptr, v)             (xchg(&(ptr)->counter, (v)))
200 #define atomic_cmpxchg(v, old, new)     (cmpxchg(&((v)->counter), (old), (new)))
201
202 #endif /* __ASM_GENERIC_ATOMIC_H */