1 #ifndef _ASM_X86_ATOMIC_32_H
2 #define _ASM_X86_ATOMIC_32_H
3
4 #include <linux/compiler.h>
5 #include <linux/types.h>
6 #include <asm/processor.h>
7 #include <asm/cmpxchg.h>
8
9 /*
10 * Atomic operations that C can't guarantee us. Useful for
11 * resource counting etc..
12 */
13
14 #define ATOMIC_INIT(i) { (i) }
15
16 /**
17 * atomic_read - read atomic variable
18 * @v: pointer of type atomic_t
19 *
20 * Atomically reads the value of @v.
21 */
22 static inline int atomic_read(const atomic_t *v)
23 {
24 return v->counter;
25 }
26
27 /**
28 * atomic_set - set atomic variable
29 * @v: pointer of type atomic_t
30 * @i: required value
31 *
32 * Atomically sets the value of @v to @i.
33 */
34 static inline void atomic_set(atomic_t *v, int i)
35 {
36 v->counter = i;
37 }
38
39 /**
40 * atomic_add - add integer to atomic variable
41 * @i: integer value to add
42 * @v: pointer of type atomic_t
43 *
44 * Atomically adds @i to @v.
45 */
46 static inline void atomic_add(int i, atomic_t *v)
47 {
48 asm volatile(LOCK_PREFIX "addl %1,%0"
49 : "+m" (v->counter)
50 : "ir" (i));
51 }
52
53 /**
54 * atomic_sub - subtract integer from 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(LOCK_PREFIX "subl %1,%0"
63 : "+m" (v->counter)
64 : "ir" (i));
65 }
66
67 /**
68 * atomic_sub_and_test - subtract value from variable and test result
69 * @i: integer value to subtract
70 * @v: pointer of type atomic_t
71 *
72 * Atomically subtracts @i from @v and returns
73 * true if the result is zero, or false for all
74 * other cases.
75 */
76 static inline int atomic_sub_and_test(int i, atomic_t *v)
77 {
78 unsigned char c;
79
80 asm volatile(LOCK_PREFIX "subl %2,%0; sete %1"
81 : "+m" (v->counter), "=qm" (c)
82 : "ir" (i) : "memory");
83 return c;
84 }
85
86 /**
87 * atomic_inc - increment atomic variable
88 * @v: pointer of type atomic_t
89 *
90 * Atomically increments @v by 1.
91 */
92 static inline void atomic_inc(atomic_t *v)
93 {
94 asm volatile(LOCK_PREFIX "incl %0"
95 : "+m" (v->counter));
96 }
97
98 /**
99 * atomic_dec - decrement atomic variable
100 * @v: pointer of type atomic_t
101 *
102 * Atomically decrements @v by 1.
103 */
104 static inline void atomic_dec(atomic_t *v)
105 {
106 asm volatile(LOCK_PREFIX "decl %0"
107 : "+m" (v->counter));
108 }
109
110 /**
111 * atomic_dec_and_test - decrement and test
112 * @v: pointer of type atomic_t
113 *
114 * Atomically decrements @v by 1 and
115 * returns true if the result is 0, or false for all other
116 * cases.
117 */
118 static inline int atomic_dec_and_test(atomic_t *v)
119 {
120 unsigned char c;
121
122 asm volatile(LOCK_PREFIX "decl %0; sete %1"
123 : "+m" (v->counter), "=qm" (c)
124 : : "memory");
125 return c != 0;
126 }
127
128 /**
129 * atomic_inc_and_test - increment and test
130 * @v: pointer of type atomic_t
131 *
132 * Atomically increments @v by 1
133 * and returns true if the result is zero, or false for all
134 * other cases.
135 */
136 static inline int atomic_inc_and_test(atomic_t *v)
137 {
138 unsigned char c;
139
140 asm volatile(LOCK_PREFIX "incl %0; sete %1"
141 : "+m" (v->counter), "=qm" (c)
142 : : "memory");
143 return c != 0;
144 }
145
146 /**
147 * atomic_add_negative - add and test if negative
148 * @v: pointer of type atomic_t
149 * @i: integer value to add
150 *
151 * Atomically adds @i to @v and returns true
152 * if the result is negative, or false when
153 * result is greater than or equal to zero.
154 */
155 static inline int atomic_add_negative(int i, atomic_t *v)
156 {
157 unsigned char c;
158
159 asm volatile(LOCK_PREFIX "addl %2,%0; sets %1"
160 : "+m" (v->counter), "=qm" (c)
161 : "ir" (i) : "memory");
162 return c;
163 }
164
165 /**
166 * atomic_add_return - add integer and return
167 * @v: pointer of type atomic_t
168 * @i: integer value to add
169 *
170 * Atomically adds @i to @v and returns @i + @v
171 */
172 static inline int atomic_add_return(int i, atomic_t *v)
173 {
174 int __i;
175 #ifdef CONFIG_M386
176 unsigned long flags;
177 if (unlikely(boot_cpu_data.x86 <= 3))
178 goto no_xadd;
179 #endif
180 /* Modern 486+ processor */
181 __i = i;
182 asm volatile(LOCK_PREFIX "xaddl %0, %1"
183 : "+r" (i), "+m" (v->counter)
184 : : "memory");
185 return i + __i;
186
187 #ifdef CONFIG_M386
188 no_xadd: /* Legacy 386 processor */
189 local_irq_save(flags);
190 __i = atomic_read(v);
191 atomic_set(v, i + __i);
192 local_irq_restore(flags);
193 return i + __i;
194 #endif
195 }
196
197 /**
198 * atomic_sub_return - subtract integer and return
199 * @v: pointer of type atomic_t
200 * @i: integer value to subtract
201 *
202 * Atomically subtracts @i from @v and returns @v - @i
203 */
204 static inline int atomic_sub_return(int i, atomic_t *v)
205 {
206 return atomic_add_return(-i, v);
207 }
208
209 static inline int atomic_cmpxchg(atomic_t *v, int old, int new)
210 {
211 return cmpxchg(&v->counter, old, new);
212 }
213
214 static inline int atomic_xchg(atomic_t *v, int new)
215 {
216 return xchg(&v->counter, new);
217 }
218
219 /**
220 * atomic_add_unless - add unless the number is already a given value
221 * @v: pointer of type atomic_t
222 * @a: the amount to add to v...
223 * @u: ...unless v is equal to u.
224 *
225 * Atomically adds @a to @v, so long as @v was not already @u.
226 * Returns non-zero if @v was not @u, and zero otherwise.
227 */
228 static inline int atomic_add_unless(atomic_t *v, int a, int u)
229 {
230 int c, old;
231 c = atomic_read(v);
232 for (;;) {
233 if (unlikely(c == (u)))
234 break;
235 old = atomic_cmpxchg((v), c, c + (a));
236 if (likely(old == c))
237 break;
238 c = old;
239 }
240 return c != (u);
241 }
242
243 #define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
244
245 #define atomic_inc_return(v) (atomic_add_return(1, v))
246 #define atomic_dec_return(v) (atomic_sub_return(1, v))
247
248 /* These are x86-specific, used by some header files */
249 #define atomic_clear_mask(mask, addr) \
250 asm volatile(LOCK_PREFIX "andl %0,%1" \
251 : : "r" (~(mask)), "m" (*(addr)) : "memory")
252
253 #define atomic_set_mask(mask, addr) \
254 asm volatile(LOCK_PREFIX "orl %0,%1" \
255 : : "r" (mask), "m" (*(addr)) : "memory")
256
257 /* Atomic operations are already serializing on x86 */
258 #define smp_mb__before_atomic_dec() barrier()
259 #define smp_mb__after_atomic_dec() barrier()
260 #define smp_mb__before_atomic_inc() barrier()
261 #define smp_mb__after_atomic_inc() barrier()
262
263 /* An 64bit atomic type */
264
265 typedef struct {
266 u64 __aligned(8) counter;
267 } atomic64_t;
268
269 #define ATOMIC64_INIT(val) { (val) }
270
271 extern u64 atomic64_cmpxchg(atomic64_t *ptr, u64 old_val, u64 new_val);
272
273 /**
274 * atomic64_xchg - xchg atomic64 variable
275 * @ptr: pointer to type atomic64_t
276 * @new_val: value to assign
277 *
278 * Atomically xchgs the value of @ptr to @new_val and returns
279 * the old value.
280 */
281 extern u64 atomic64_xchg(atomic64_t *ptr, u64 new_val);
282
283 /**
284 * atomic64_set - set atomic64 variable
285 * @ptr: pointer to type atomic64_t
286 * @new_val: value to assign
287 *
288 * Atomically sets the value of @ptr to @new_val.
289 */
290 extern void atomic64_set(atomic64_t *ptr, u64 new_val);
291
292 /**
293 * atomic64_read - read atomic64 variable
294 * @ptr: pointer to type atomic64_t
295 *
296 * Atomically reads the value of @ptr and returns it.
297 */
298 static inline u64 atomic64_read(atomic64_t *ptr)
299 {
300 u64 res;
301
302 /*
303 * Note, we inline this atomic64_t primitive because
304 * it only clobbers EAX/EDX and leaves the others
305 * untouched. We also (somewhat subtly) rely on the
306 * fact that cmpxchg8b returns the current 64-bit value
307 * of the memory location we are touching:
308 */
309 asm volatile(
310 "mov %%ebx, %%eax\n\t"
311 "mov %%ecx, %%edx\n\t"
312 LOCK_PREFIX "cmpxchg8b %1\n"
313 : "=&A" (res)
314 : "m" (*ptr)
315 );
316
317 return res;
318 }
319
320 extern u64 atomic64_read(atomic64_t *ptr);
321
322 /**
323 * atomic64_add_return - add and return
324 * @delta: integer value to add
325 * @ptr: pointer to type atomic64_t
326 *
327 * Atomically adds @delta to @ptr and returns @delta + *@ptr
328 */
329 extern u64 atomic64_add_return(u64 delta, atomic64_t *ptr);
330
331 /*
332 * Other variants with different arithmetic operators:
333 */
334 extern u64 atomic64_sub_return(u64 delta, atomic64_t *ptr);
335 extern u64 atomic64_inc_return(atomic64_t *ptr);
336 extern u64 atomic64_dec_return(atomic64_t *ptr);
337
338 /**
339 * atomic64_add - add integer to atomic64 variable
340 * @delta: integer value to add
341 * @ptr: pointer to type atomic64_t
342 *
343 * Atomically adds @delta to @ptr.
344 */
345 extern void atomic64_add(u64 delta, atomic64_t *ptr);
346
347 /**
348 * atomic64_sub - subtract the atomic64 variable
349 * @delta: integer value to subtract
350 * @ptr: pointer to type atomic64_t
351 *
352 * Atomically subtracts @delta from @ptr.
353 */
354 extern void atomic64_sub(u64 delta, atomic64_t *ptr);
355
356 /**
357 * atomic64_sub_and_test - subtract value from variable and test result
358 * @delta: integer value to subtract
359 * @ptr: pointer to type atomic64_t
360 *
361 * Atomically subtracts @delta from @ptr and returns
362 * true if the result is zero, or false for all
363 * other cases.
364 */
365 extern int atomic64_sub_and_test(u64 delta, atomic64_t *ptr);
366
367 /**
368 * atomic64_inc - increment atomic64 variable
369 * @ptr: pointer to type atomic64_t
370 *
371 * Atomically increments @ptr by 1.
372 */
373 extern void atomic64_inc(atomic64_t *ptr);
374
375 /**
376 * atomic64_dec - decrement atomic64 variable
377 * @ptr: pointer to type atomic64_t
378 *
379 * Atomically decrements @ptr by 1.
380 */
381 extern void atomic64_dec(atomic64_t *ptr);
382
383 /**
384 * atomic64_dec_and_test - decrement and test
385 * @ptr: pointer to type atomic64_t
386 *
387 * Atomically decrements @ptr by 1 and
388 * returns true if the result is 0, or false for all other
389 * cases.
390 */
391 extern int atomic64_dec_and_test(atomic64_t *ptr);
392
393 /**
394 * atomic64_inc_and_test - increment and test
395 * @ptr: pointer to type atomic64_t
396 *
397 * Atomically increments @ptr by 1
398 * and returns true if the result is zero, or false for all
399 * other cases.
400 */
401 extern int atomic64_inc_and_test(atomic64_t *ptr);
402
403 /**
404 * atomic64_add_negative - add and test if negative
405 * @delta: integer value to add
406 * @ptr: pointer to type atomic64_t
407 *
408 * Atomically adds @delta to @ptr and returns true
409 * if the result is negative, or false when
410 * result is greater than or equal to zero.
411 */
412 extern int atomic64_add_negative(u64 delta, atomic64_t *ptr);
413
414 #include <asm-generic/atomic-long.h>
415 #endif /* _ASM_X86_ATOMIC_32_H */
416
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