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1da177e4 LT |
1 | #ifndef __ARCH_I386_ATOMIC__ |
2 | #define __ARCH_I386_ATOMIC__ | |
3 | ||
1da177e4 LT |
4 | #include <linux/compiler.h> |
5 | #include <asm/processor.h> | |
6 | ||
7 | /* | |
8 | * Atomic operations that C can't guarantee us. Useful for | |
9 | * resource counting etc.. | |
10 | */ | |
11 | ||
1da177e4 LT |
12 | /* |
13 | * Make sure gcc doesn't try to be clever and move things around | |
14 | * on us. We need to use _exactly_ the address the user gave us, | |
15 | * not some alias that contains the same information. | |
16 | */ | |
f9e9dcb3 | 17 | typedef struct { int counter; } atomic_t; |
1da177e4 LT |
18 | |
19 | #define ATOMIC_INIT(i) { (i) } | |
20 | ||
21 | /** | |
22 | * atomic_read - read atomic variable | |
23 | * @v: pointer of type atomic_t | |
24 | * | |
25 | * Atomically reads the value of @v. | |
26 | */ | |
27 | #define atomic_read(v) ((v)->counter) | |
28 | ||
29 | /** | |
30 | * atomic_set - set atomic variable | |
31 | * @v: pointer of type atomic_t | |
32 | * @i: required value | |
33 | * | |
34 | * Atomically sets the value of @v to @i. | |
35 | */ | |
36 | #define atomic_set(v,i) (((v)->counter) = (i)) | |
37 | ||
38 | /** | |
39 | * atomic_add - add integer to atomic variable | |
40 | * @i: integer value to add | |
41 | * @v: pointer of type atomic_t | |
42 | * | |
43 | * Atomically adds @i to @v. | |
44 | */ | |
45 | static __inline__ void atomic_add(int i, atomic_t *v) | |
46 | { | |
47 | __asm__ __volatile__( | |
9a0b5817 | 48 | LOCK_PREFIX "addl %1,%0" |
b862f3b0 LT |
49 | :"+m" (v->counter) |
50 | :"ir" (i)); | |
1da177e4 LT |
51 | } |
52 | ||
53 | /** | |
54 | * atomic_sub - subtract the atomic variable | |
55 | * @i: integer value to subtract | |
56 | * @v: pointer of type atomic_t | |
57 | * | |
58 | * Atomically subtracts @i from @v. | |
59 | */ | |
60 | static __inline__ void atomic_sub(int i, atomic_t *v) | |
61 | { | |
62 | __asm__ __volatile__( | |
9a0b5817 | 63 | LOCK_PREFIX "subl %1,%0" |
b862f3b0 LT |
64 | :"+m" (v->counter) |
65 | :"ir" (i)); | |
1da177e4 LT |
66 | } |
67 | ||
68 | /** | |
69 | * atomic_sub_and_test - subtract value from variable and test result | |
70 | * @i: integer value to subtract | |
71 | * @v: pointer of type atomic_t | |
72 | * | |
73 | * Atomically subtracts @i from @v and returns | |
74 | * true if the result is zero, or false for all | |
75 | * other cases. | |
76 | */ | |
77 | static __inline__ int atomic_sub_and_test(int i, atomic_t *v) | |
78 | { | |
79 | unsigned char c; | |
80 | ||
81 | __asm__ __volatile__( | |
9a0b5817 | 82 | LOCK_PREFIX "subl %2,%0; sete %1" |
b862f3b0 LT |
83 | :"+m" (v->counter), "=qm" (c) |
84 | :"ir" (i) : "memory"); | |
1da177e4 LT |
85 | return c; |
86 | } | |
87 | ||
88 | /** | |
89 | * atomic_inc - increment atomic variable | |
90 | * @v: pointer of type atomic_t | |
91 | * | |
92 | * Atomically increments @v by 1. | |
93 | */ | |
94 | static __inline__ void atomic_inc(atomic_t *v) | |
95 | { | |
96 | __asm__ __volatile__( | |
9a0b5817 | 97 | LOCK_PREFIX "incl %0" |
b862f3b0 | 98 | :"+m" (v->counter)); |
1da177e4 LT |
99 | } |
100 | ||
101 | /** | |
102 | * atomic_dec - decrement atomic variable | |
103 | * @v: pointer of type atomic_t | |
104 | * | |
105 | * Atomically decrements @v by 1. | |
106 | */ | |
107 | static __inline__ void atomic_dec(atomic_t *v) | |
108 | { | |
109 | __asm__ __volatile__( | |
9a0b5817 | 110 | LOCK_PREFIX "decl %0" |
b862f3b0 | 111 | :"+m" (v->counter)); |
1da177e4 LT |
112 | } |
113 | ||
114 | /** | |
115 | * atomic_dec_and_test - decrement and test | |
116 | * @v: pointer of type atomic_t | |
117 | * | |
118 | * Atomically decrements @v by 1 and | |
119 | * returns true if the result is 0, or false for all other | |
120 | * cases. | |
121 | */ | |
122 | static __inline__ int atomic_dec_and_test(atomic_t *v) | |
123 | { | |
124 | unsigned char c; | |
125 | ||
126 | __asm__ __volatile__( | |
9a0b5817 | 127 | LOCK_PREFIX "decl %0; sete %1" |
b862f3b0 LT |
128 | :"+m" (v->counter), "=qm" (c) |
129 | : : "memory"); | |
1da177e4 LT |
130 | return c != 0; |
131 | } | |
132 | ||
133 | /** | |
134 | * atomic_inc_and_test - increment and test | |
135 | * @v: pointer of type atomic_t | |
136 | * | |
137 | * Atomically increments @v by 1 | |
138 | * and returns true if the result is zero, or false for all | |
139 | * other cases. | |
140 | */ | |
141 | static __inline__ int atomic_inc_and_test(atomic_t *v) | |
142 | { | |
143 | unsigned char c; | |
144 | ||
145 | __asm__ __volatile__( | |
9a0b5817 | 146 | LOCK_PREFIX "incl %0; sete %1" |
b862f3b0 LT |
147 | :"+m" (v->counter), "=qm" (c) |
148 | : : "memory"); | |
1da177e4 LT |
149 | return c != 0; |
150 | } | |
151 | ||
152 | /** | |
153 | * atomic_add_negative - add and test if negative | |
154 | * @v: pointer of type atomic_t | |
155 | * @i: integer value to add | |
156 | * | |
157 | * Atomically adds @i to @v and returns true | |
158 | * if the result is negative, or false when | |
159 | * result is greater than or equal to zero. | |
160 | */ | |
161 | static __inline__ int atomic_add_negative(int i, atomic_t *v) | |
162 | { | |
163 | unsigned char c; | |
164 | ||
165 | __asm__ __volatile__( | |
9a0b5817 | 166 | LOCK_PREFIX "addl %2,%0; sets %1" |
b862f3b0 LT |
167 | :"+m" (v->counter), "=qm" (c) |
168 | :"ir" (i) : "memory"); | |
1da177e4 LT |
169 | return c; |
170 | } | |
171 | ||
172 | /** | |
173 | * atomic_add_return - add and return | |
174 | * @v: pointer of type atomic_t | |
175 | * @i: integer value to add | |
176 | * | |
177 | * Atomically adds @i to @v and returns @i + @v | |
178 | */ | |
179 | static __inline__ int atomic_add_return(int i, atomic_t *v) | |
180 | { | |
181 | int __i; | |
182 | #ifdef CONFIG_M386 | |
1bb858f2 | 183 | unsigned long flags; |
1da177e4 LT |
184 | if(unlikely(boot_cpu_data.x86==3)) |
185 | goto no_xadd; | |
186 | #endif | |
187 | /* Modern 486+ processor */ | |
188 | __i = i; | |
189 | __asm__ __volatile__( | |
e4b522d7 DS |
190 | LOCK_PREFIX "xaddl %0, %1" |
191 | :"+r" (i), "+m" (v->counter) | |
192 | : : "memory"); | |
1da177e4 LT |
193 | return i + __i; |
194 | ||
195 | #ifdef CONFIG_M386 | |
196 | no_xadd: /* Legacy 386 processor */ | |
1bb858f2 | 197 | local_irq_save(flags); |
1da177e4 LT |
198 | __i = atomic_read(v); |
199 | atomic_set(v, i + __i); | |
1bb858f2 | 200 | local_irq_restore(flags); |
1da177e4 LT |
201 | return i + __i; |
202 | #endif | |
203 | } | |
204 | ||
205 | static __inline__ int atomic_sub_return(int i, atomic_t *v) | |
206 | { | |
207 | return atomic_add_return(-i,v); | |
208 | } | |
209 | ||
4a6dae6d | 210 | #define atomic_cmpxchg(v, old, new) ((int)cmpxchg(&((v)->counter), old, new)) |
ffbf670f | 211 | #define atomic_xchg(v, new) (xchg(&((v)->counter), new)) |
4a6dae6d | 212 | |
8426e1f6 | 213 | /** |
72fd4a35 | 214 | * atomic_add_unless - add unless the number is already a given value |
8426e1f6 NP |
215 | * @v: pointer of type atomic_t |
216 | * @a: the amount to add to v... | |
217 | * @u: ...unless v is equal to u. | |
218 | * | |
72fd4a35 | 219 | * Atomically adds @a to @v, so long as @v was not already @u. |
8426e1f6 NP |
220 | * Returns non-zero if @v was not @u, and zero otherwise. |
221 | */ | |
222 | #define atomic_add_unless(v, a, u) \ | |
223 | ({ \ | |
224 | int c, old; \ | |
225 | c = atomic_read(v); \ | |
0b2fcfdb NP |
226 | for (;;) { \ |
227 | if (unlikely(c == (u))) \ | |
228 | break; \ | |
229 | old = atomic_cmpxchg((v), c, c + (a)); \ | |
230 | if (likely(old == c)) \ | |
231 | break; \ | |
8426e1f6 | 232 | c = old; \ |
0b2fcfdb | 233 | } \ |
8426e1f6 NP |
234 | c != (u); \ |
235 | }) | |
236 | #define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0) | |
237 | ||
1da177e4 LT |
238 | #define atomic_inc_return(v) (atomic_add_return(1,v)) |
239 | #define atomic_dec_return(v) (atomic_sub_return(1,v)) | |
240 | ||
241 | /* These are x86-specific, used by some header files */ | |
242 | #define atomic_clear_mask(mask, addr) \ | |
9a0b5817 | 243 | __asm__ __volatile__(LOCK_PREFIX "andl %0,%1" \ |
1da177e4 LT |
244 | : : "r" (~(mask)),"m" (*addr) : "memory") |
245 | ||
246 | #define atomic_set_mask(mask, addr) \ | |
9a0b5817 | 247 | __asm__ __volatile__(LOCK_PREFIX "orl %0,%1" \ |
1da177e4 LT |
248 | : : "r" (mask),"m" (*(addr)) : "memory") |
249 | ||
250 | /* Atomic operations are already serializing on x86 */ | |
251 | #define smp_mb__before_atomic_dec() barrier() | |
252 | #define smp_mb__after_atomic_dec() barrier() | |
253 | #define smp_mb__before_atomic_inc() barrier() | |
254 | #define smp_mb__after_atomic_inc() barrier() | |
255 | ||
d3cb4871 | 256 | #include <asm-generic/atomic.h> |
1da177e4 | 257 | #endif |