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77ef50a5 VN |
1 | #ifndef ASM_X86__ATOMIC_32_H |
2 | #define ASM_X86__ATOMIC_32_H | |
1da177e4 | 3 | |
1da177e4 LT |
4 | #include <linux/compiler.h> |
5 | #include <asm/processor.h> | |
a436ed9c | 6 | #include <asm/cmpxchg.h> |
1da177e4 LT |
7 | |
8 | /* | |
9 | * Atomic operations that C can't guarantee us. Useful for | |
10 | * resource counting etc.. | |
11 | */ | |
12 | ||
1da177e4 LT |
13 | /* |
14 | * Make sure gcc doesn't try to be clever and move things around | |
15 | * on us. We need to use _exactly_ the address the user gave us, | |
16 | * not some alias that contains the same information. | |
17 | */ | |
78ff12ee JP |
18 | typedef struct { |
19 | int counter; | |
20 | } atomic_t; | |
1da177e4 LT |
21 | |
22 | #define ATOMIC_INIT(i) { (i) } | |
23 | ||
24 | /** | |
25 | * atomic_read - read atomic variable | |
26 | * @v: pointer of type atomic_t | |
78ff12ee | 27 | * |
1da177e4 | 28 | * Atomically reads the value of @v. |
78ff12ee | 29 | */ |
1da177e4 LT |
30 | #define atomic_read(v) ((v)->counter) |
31 | ||
32 | /** | |
33 | * atomic_set - set atomic variable | |
34 | * @v: pointer of type atomic_t | |
35 | * @i: required value | |
78ff12ee | 36 | * |
1da177e4 | 37 | * Atomically sets the value of @v to @i. |
78ff12ee JP |
38 | */ |
39 | #define atomic_set(v, i) (((v)->counter) = (i)) | |
1da177e4 LT |
40 | |
41 | /** | |
42 | * atomic_add - add integer to atomic variable | |
43 | * @i: integer value to add | |
44 | * @v: pointer of type atomic_t | |
78ff12ee | 45 | * |
1da177e4 LT |
46 | * Atomically adds @i to @v. |
47 | */ | |
78ff12ee | 48 | static inline void atomic_add(int i, atomic_t *v) |
1da177e4 | 49 | { |
78ff12ee JP |
50 | asm volatile(LOCK_PREFIX "addl %1,%0" |
51 | : "+m" (v->counter) | |
52 | : "ir" (i)); | |
1da177e4 LT |
53 | } |
54 | ||
55 | /** | |
cc38682f | 56 | * atomic_sub - subtract integer from atomic variable |
1da177e4 LT |
57 | * @i: integer value to subtract |
58 | * @v: pointer of type atomic_t | |
78ff12ee | 59 | * |
1da177e4 LT |
60 | * Atomically subtracts @i from @v. |
61 | */ | |
78ff12ee | 62 | static inline void atomic_sub(int i, atomic_t *v) |
1da177e4 | 63 | { |
78ff12ee JP |
64 | asm volatile(LOCK_PREFIX "subl %1,%0" |
65 | : "+m" (v->counter) | |
66 | : "ir" (i)); | |
1da177e4 LT |
67 | } |
68 | ||
69 | /** | |
70 | * atomic_sub_and_test - subtract value from variable and test result | |
71 | * @i: integer value to subtract | |
72 | * @v: pointer of type atomic_t | |
78ff12ee | 73 | * |
1da177e4 LT |
74 | * Atomically subtracts @i from @v and returns |
75 | * true if the result is zero, or false for all | |
76 | * other cases. | |
77 | */ | |
78ff12ee | 78 | static inline int atomic_sub_and_test(int i, atomic_t *v) |
1da177e4 LT |
79 | { |
80 | unsigned char c; | |
81 | ||
78ff12ee JP |
82 | asm volatile(LOCK_PREFIX "subl %2,%0; sete %1" |
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 | |
78ff12ee | 91 | * |
1da177e4 | 92 | * Atomically increments @v by 1. |
78ff12ee JP |
93 | */ |
94 | static inline void atomic_inc(atomic_t *v) | |
1da177e4 | 95 | { |
78ff12ee JP |
96 | asm volatile(LOCK_PREFIX "incl %0" |
97 | : "+m" (v->counter)); | |
1da177e4 LT |
98 | } |
99 | ||
100 | /** | |
101 | * atomic_dec - decrement atomic variable | |
102 | * @v: pointer of type atomic_t | |
78ff12ee | 103 | * |
1da177e4 | 104 | * Atomically decrements @v by 1. |
78ff12ee JP |
105 | */ |
106 | static inline void atomic_dec(atomic_t *v) | |
1da177e4 | 107 | { |
78ff12ee JP |
108 | asm volatile(LOCK_PREFIX "decl %0" |
109 | : "+m" (v->counter)); | |
1da177e4 LT |
110 | } |
111 | ||
112 | /** | |
113 | * atomic_dec_and_test - decrement and test | |
114 | * @v: pointer of type atomic_t | |
78ff12ee | 115 | * |
1da177e4 LT |
116 | * Atomically decrements @v by 1 and |
117 | * returns true if the result is 0, or false for all other | |
118 | * cases. | |
78ff12ee JP |
119 | */ |
120 | static inline int atomic_dec_and_test(atomic_t *v) | |
1da177e4 LT |
121 | { |
122 | unsigned char c; | |
123 | ||
78ff12ee JP |
124 | asm volatile(LOCK_PREFIX "decl %0; sete %1" |
125 | : "+m" (v->counter), "=qm" (c) | |
126 | : : "memory"); | |
1da177e4 LT |
127 | return c != 0; |
128 | } | |
129 | ||
130 | /** | |
78ff12ee | 131 | * atomic_inc_and_test - increment and test |
1da177e4 | 132 | * @v: pointer of type atomic_t |
78ff12ee | 133 | * |
1da177e4 LT |
134 | * Atomically increments @v by 1 |
135 | * and returns true if the result is zero, or false for all | |
136 | * other cases. | |
78ff12ee JP |
137 | */ |
138 | static inline int atomic_inc_and_test(atomic_t *v) | |
1da177e4 LT |
139 | { |
140 | unsigned char c; | |
141 | ||
78ff12ee JP |
142 | asm volatile(LOCK_PREFIX "incl %0; sete %1" |
143 | : "+m" (v->counter), "=qm" (c) | |
144 | : : "memory"); | |
1da177e4 LT |
145 | return c != 0; |
146 | } | |
147 | ||
148 | /** | |
149 | * atomic_add_negative - add and test if negative | |
150 | * @v: pointer of type atomic_t | |
151 | * @i: integer value to add | |
78ff12ee | 152 | * |
1da177e4 LT |
153 | * Atomically adds @i to @v and returns true |
154 | * if the result is negative, or false when | |
155 | * result is greater than or equal to zero. | |
78ff12ee JP |
156 | */ |
157 | static inline int atomic_add_negative(int i, atomic_t *v) | |
1da177e4 LT |
158 | { |
159 | unsigned char c; | |
160 | ||
78ff12ee JP |
161 | asm volatile(LOCK_PREFIX "addl %2,%0; sets %1" |
162 | : "+m" (v->counter), "=qm" (c) | |
163 | : "ir" (i) : "memory"); | |
1da177e4 LT |
164 | return c; |
165 | } | |
166 | ||
167 | /** | |
cc38682f | 168 | * atomic_add_return - add integer and return |
1da177e4 LT |
169 | * @v: pointer of type atomic_t |
170 | * @i: integer value to add | |
171 | * | |
172 | * Atomically adds @i to @v and returns @i + @v | |
173 | */ | |
78ff12ee | 174 | static inline int atomic_add_return(int i, atomic_t *v) |
1da177e4 LT |
175 | { |
176 | int __i; | |
177 | #ifdef CONFIG_M386 | |
1bb858f2 | 178 | unsigned long flags; |
78ff12ee | 179 | if (unlikely(boot_cpu_data.x86 <= 3)) |
1da177e4 LT |
180 | goto no_xadd; |
181 | #endif | |
182 | /* Modern 486+ processor */ | |
183 | __i = i; | |
78ff12ee JP |
184 | asm volatile(LOCK_PREFIX "xaddl %0, %1" |
185 | : "+r" (i), "+m" (v->counter) | |
186 | : : "memory"); | |
1da177e4 LT |
187 | return i + __i; |
188 | ||
189 | #ifdef CONFIG_M386 | |
190 | no_xadd: /* Legacy 386 processor */ | |
1bb858f2 | 191 | local_irq_save(flags); |
1da177e4 LT |
192 | __i = atomic_read(v); |
193 | atomic_set(v, i + __i); | |
1bb858f2 | 194 | local_irq_restore(flags); |
1da177e4 LT |
195 | return i + __i; |
196 | #endif | |
197 | } | |
198 | ||
cc38682f RD |
199 | /** |
200 | * atomic_sub_return - subtract integer and return | |
201 | * @v: pointer of type atomic_t | |
202 | * @i: integer value to subtract | |
203 | * | |
204 | * Atomically subtracts @i from @v and returns @v - @i | |
205 | */ | |
78ff12ee | 206 | static inline int atomic_sub_return(int i, atomic_t *v) |
1da177e4 | 207 | { |
78ff12ee | 208 | return atomic_add_return(-i, v); |
1da177e4 LT |
209 | } |
210 | ||
e656e245 MD |
211 | #define atomic_cmpxchg(v, old, new) (cmpxchg(&((v)->counter), (old), (new))) |
212 | #define atomic_xchg(v, new) (xchg(&((v)->counter), (new))) | |
4a6dae6d | 213 | |
8426e1f6 | 214 | /** |
72fd4a35 | 215 | * atomic_add_unless - add unless the number is already a given value |
8426e1f6 NP |
216 | * @v: pointer of type atomic_t |
217 | * @a: the amount to add to v... | |
218 | * @u: ...unless v is equal to u. | |
219 | * | |
72fd4a35 | 220 | * Atomically adds @a to @v, so long as @v was not already @u. |
8426e1f6 NP |
221 | * Returns non-zero if @v was not @u, and zero otherwise. |
222 | */ | |
78ff12ee | 223 | static inline int atomic_add_unless(atomic_t *v, int a, int u) |
2856f5e3 MD |
224 | { |
225 | int c, old; | |
226 | c = atomic_read(v); | |
227 | for (;;) { | |
228 | if (unlikely(c == (u))) | |
229 | break; | |
230 | old = atomic_cmpxchg((v), c, c + (a)); | |
231 | if (likely(old == c)) | |
232 | break; | |
233 | c = old; | |
234 | } | |
235 | return c != (u); | |
236 | } | |
237 | ||
8426e1f6 NP |
238 | #define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0) |
239 | ||
78ff12ee JP |
240 | #define atomic_inc_return(v) (atomic_add_return(1, v)) |
241 | #define atomic_dec_return(v) (atomic_sub_return(1, v)) | |
1da177e4 LT |
242 | |
243 | /* These are x86-specific, used by some header files */ | |
78ff12ee JP |
244 | #define atomic_clear_mask(mask, addr) \ |
245 | asm volatile(LOCK_PREFIX "andl %0,%1" \ | |
246 | : : "r" (~(mask)), "m" (*(addr)) : "memory") | |
1da177e4 | 247 | |
78ff12ee JP |
248 | #define atomic_set_mask(mask, addr) \ |
249 | asm volatile(LOCK_PREFIX "orl %0,%1" \ | |
250 | : : "r" (mask), "m" (*(addr)) : "memory") | |
1da177e4 LT |
251 | |
252 | /* Atomic operations are already serializing on x86 */ | |
253 | #define smp_mb__before_atomic_dec() barrier() | |
254 | #define smp_mb__after_atomic_dec() barrier() | |
255 | #define smp_mb__before_atomic_inc() barrier() | |
256 | #define smp_mb__after_atomic_inc() barrier() | |
257 | ||
d3cb4871 | 258 | #include <asm-generic/atomic.h> |
77ef50a5 | 259 | #endif /* ASM_X86__ATOMIC_32_H */ |