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
19 spinlock_t __atomic_hash[ATOMIC_HASH_SIZE] = {
20 [0 ... (ATOMIC_HASH_SIZE-1)] = __SPIN_LOCK_UNLOCKED(__atomic_hash)
21 };
22
23 #else /* SMP */
24
25 static 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) \
32 int 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 } \
44 EXPORT_SYMBOL(atomic_fetch_##op);
45
46 #define ATOMIC_OP_RETURN(op, c_op) \
47 int 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 } \
58 EXPORT_SYMBOL(atomic_##op##_return);
59
60 ATOMIC_OP_RETURN(add, +=)
61
62 ATOMIC_FETCH_OP(add, +=)
63 ATOMIC_FETCH_OP(and, &=)
64 ATOMIC_FETCH_OP(or, |=)
65 ATOMIC_FETCH_OP(xor, ^=)
66
67 #undef ATOMIC_FETCH_OP
68 #undef ATOMIC_OP_RETURN
69
atomic_xchg(atomic_t * v,int new)70 int 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 }
81 EXPORT_SYMBOL(atomic_xchg);
82
atomic_cmpxchg(atomic_t * v,int old,int new)83 int 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 }
96 EXPORT_SYMBOL(atomic_cmpxchg);
97
atomic_fetch_add_unless(atomic_t * v,int a,int u)98 int 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 }
110 EXPORT_SYMBOL(atomic_fetch_add_unless);
111
112 /* Atomic operations are already serializing */
atomic_set(atomic_t * v,int i)113 void 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 }
121 EXPORT_SYMBOL(atomic_set);
122
___set_bit(unsigned long * addr,unsigned long mask)123 unsigned long ___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 }
134 EXPORT_SYMBOL(___set_bit);
135
___clear_bit(unsigned long * addr,unsigned long mask)136 unsigned long ___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 }
147 EXPORT_SYMBOL(___clear_bit);
148
___change_bit(unsigned long * addr,unsigned long mask)149 unsigned long ___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 }
160 EXPORT_SYMBOL(___change_bit);
161
__cmpxchg_u32(volatile u32 * ptr,u32 old,u32 new)162 unsigned long __cmpxchg_u32(volatile u32 *ptr, u32 old, u32 new)
163 {
164 unsigned long flags;
165 u32 prev;
166
167 spin_lock_irqsave(ATOMIC_HASH(ptr), flags);
168 if ((prev = *ptr) == old)
169 *ptr = new;
170 spin_unlock_irqrestore(ATOMIC_HASH(ptr), flags);
171
172 return (unsigned long)prev;
173 }
174 EXPORT_SYMBOL(__cmpxchg_u32);
175
__cmpxchg_u64(u64 * ptr,u64 old,u64 new)176 u64 __cmpxchg_u64(u64 *ptr, u64 old, u64 new)
177 {
178 unsigned long flags;
179 u64 prev;
180
181 spin_lock_irqsave(ATOMIC_HASH(ptr), flags);
182 if ((prev = *ptr) == old)
183 *ptr = new;
184 spin_unlock_irqrestore(ATOMIC_HASH(ptr), flags);
185
186 return prev;
187 }
188 EXPORT_SYMBOL(__cmpxchg_u64);
189
__xchg_u32(volatile u32 * ptr,u32 new)190 unsigned long __xchg_u32(volatile u32 *ptr, u32 new)
191 {
192 unsigned long flags;
193 u32 prev;
194
195 spin_lock_irqsave(ATOMIC_HASH(ptr), flags);
196 prev = *ptr;
197 *ptr = new;
198 spin_unlock_irqrestore(ATOMIC_HASH(ptr), flags);
199
200 return (unsigned long)prev;
201 }
202 EXPORT_SYMBOL(__xchg_u32);
203
