Linux kernel mirror (for testing)
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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * atomic32.c: 32-bit atomic_t implementation
4 *
5 * Copyright (C) 2004 Keith M Wesolowski
6 * Copyright (C) 2007 Kyle McMartin
7 *
8 * Based on asm-parisc/atomic.h Copyright (C) 2000 Philipp Rumpf
9 */
10
11#include <linux/atomic.h>
12#include <linux/spinlock.h>
13#include <linux/module.h>
14
15#ifdef CONFIG_SMP
16#define ATOMIC_HASH_SIZE 4
17#define ATOMIC_HASH(a) (&__atomic_hash[(((unsigned long)a)>>8) & (ATOMIC_HASH_SIZE-1)])
18
19spinlock_t __atomic_hash[ATOMIC_HASH_SIZE] = {
20 [0 ... (ATOMIC_HASH_SIZE-1)] = __SPIN_LOCK_UNLOCKED(__atomic_hash)
21};
22
23#else /* SMP */
24
25static DEFINE_SPINLOCK(dummy);
26#define ATOMIC_HASH_SIZE 1
27#define ATOMIC_HASH(a) (&dummy)
28
29#endif /* SMP */
30
31#define ATOMIC_FETCH_OP(op, c_op) \
32int arch_atomic_fetch_##op(int i, atomic_t *v) \
33{ \
34 int ret; \
35 unsigned long flags; \
36 spin_lock_irqsave(ATOMIC_HASH(v), flags); \
37 \
38 ret = v->counter; \
39 v->counter c_op i; \
40 \
41 spin_unlock_irqrestore(ATOMIC_HASH(v), flags); \
42 return ret; \
43} \
44EXPORT_SYMBOL(arch_atomic_fetch_##op);
45
46#define ATOMIC_OP_RETURN(op, c_op) \
47int arch_atomic_##op##_return(int i, atomic_t *v) \
48{ \
49 int ret; \
50 unsigned long flags; \
51 spin_lock_irqsave(ATOMIC_HASH(v), flags); \
52 \
53 ret = (v->counter c_op i); \
54 \
55 spin_unlock_irqrestore(ATOMIC_HASH(v), flags); \
56 return ret; \
57} \
58EXPORT_SYMBOL(arch_atomic_##op##_return);
59
60ATOMIC_OP_RETURN(add, +=)
61
62ATOMIC_FETCH_OP(add, +=)
63ATOMIC_FETCH_OP(and, &=)
64ATOMIC_FETCH_OP(or, |=)
65ATOMIC_FETCH_OP(xor, ^=)
66
67#undef ATOMIC_FETCH_OP
68#undef ATOMIC_OP_RETURN
69
70int arch_atomic_xchg(atomic_t *v, int new)
71{
72 int ret;
73 unsigned long flags;
74
75 spin_lock_irqsave(ATOMIC_HASH(v), flags);
76 ret = v->counter;
77 v->counter = new;
78 spin_unlock_irqrestore(ATOMIC_HASH(v), flags);
79 return ret;
80}
81EXPORT_SYMBOL(arch_atomic_xchg);
82
83int arch_atomic_cmpxchg(atomic_t *v, int old, int new)
84{
85 int ret;
86 unsigned long flags;
87
88 spin_lock_irqsave(ATOMIC_HASH(v), flags);
89 ret = v->counter;
90 if (likely(ret == old))
91 v->counter = new;
92
93 spin_unlock_irqrestore(ATOMIC_HASH(v), flags);
94 return ret;
95}
96EXPORT_SYMBOL(arch_atomic_cmpxchg);
97
98int arch_atomic_fetch_add_unless(atomic_t *v, int a, int u)
99{
100 int ret;
101 unsigned long flags;
102
103 spin_lock_irqsave(ATOMIC_HASH(v), flags);
104 ret = v->counter;
105 if (ret != u)
106 v->counter += a;
107 spin_unlock_irqrestore(ATOMIC_HASH(v), flags);
108 return ret;
109}
110EXPORT_SYMBOL(arch_atomic_fetch_add_unless);
111
112/* Atomic operations are already serializing */
113void arch_atomic_set(atomic_t *v, int i)
114{
115 unsigned long flags;
116
117 spin_lock_irqsave(ATOMIC_HASH(v), flags);
118 v->counter = i;
119 spin_unlock_irqrestore(ATOMIC_HASH(v), flags);
120}
121EXPORT_SYMBOL(arch_atomic_set);
122
123unsigned long sp32___set_bit(unsigned long *addr, unsigned long mask)
124{
125 unsigned long old, flags;
126
127 spin_lock_irqsave(ATOMIC_HASH(addr), flags);
128 old = *addr;
129 *addr = old | mask;
130 spin_unlock_irqrestore(ATOMIC_HASH(addr), flags);
131
132 return old & mask;
133}
134EXPORT_SYMBOL(sp32___set_bit);
135
136unsigned long sp32___clear_bit(unsigned long *addr, unsigned long mask)
137{
138 unsigned long old, flags;
139
140 spin_lock_irqsave(ATOMIC_HASH(addr), flags);
141 old = *addr;
142 *addr = old & ~mask;
143 spin_unlock_irqrestore(ATOMIC_HASH(addr), flags);
144
145 return old & mask;
146}
147EXPORT_SYMBOL(sp32___clear_bit);
148
149unsigned long sp32___change_bit(unsigned long *addr, unsigned long mask)
150{
151 unsigned long old, flags;
152
153 spin_lock_irqsave(ATOMIC_HASH(addr), flags);
154 old = *addr;
155 *addr = old ^ mask;
156 spin_unlock_irqrestore(ATOMIC_HASH(addr), flags);
157
158 return old & mask;
159}
160EXPORT_SYMBOL(sp32___change_bit);
161
162#define CMPXCHG(T) \
163 T __cmpxchg_##T(volatile T *ptr, T old, T new) \
164 { \
165 unsigned long flags; \
166 T prev; \
167 \
168 spin_lock_irqsave(ATOMIC_HASH(ptr), flags); \
169 if ((prev = *ptr) == old) \
170 *ptr = new; \
171 spin_unlock_irqrestore(ATOMIC_HASH(ptr), flags);\
172 \
173 return prev; \
174 }
175
176CMPXCHG(u8)
177CMPXCHG(u16)
178CMPXCHG(u32)
179CMPXCHG(u64)
180EXPORT_SYMBOL(__cmpxchg_u8);
181EXPORT_SYMBOL(__cmpxchg_u16);
182EXPORT_SYMBOL(__cmpxchg_u32);
183EXPORT_SYMBOL(__cmpxchg_u64);
184
185unsigned long __xchg_u32(volatile u32 *ptr, u32 new)
186{
187 unsigned long flags;
188 u32 prev;
189
190 spin_lock_irqsave(ATOMIC_HASH(ptr), flags);
191 prev = *ptr;
192 *ptr = new;
193 spin_unlock_irqrestore(ATOMIC_HASH(ptr), flags);
194
195 return (unsigned long)prev;
196}
197EXPORT_SYMBOL(__xchg_u32);