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[people/ms/linux.git] / arch / mips / include / asm / atomic.h
1 /*
2 * Atomic operations that C can't guarantee us. Useful for
3 * resource counting etc..
4 *
5 * But use these as seldom as possible since they are much more slower
6 * than regular operations.
7 *
8 * This file is subject to the terms and conditions of the GNU General Public
9 * License. See the file "COPYING" in the main directory of this archive
10 * for more details.
11 *
12 * Copyright (C) 1996, 97, 99, 2000, 03, 04, 06 by Ralf Baechle
13 */
14 #ifndef _ASM_ATOMIC_H
15 #define _ASM_ATOMIC_H
16
17 #include <linux/irqflags.h>
18 #include <linux/types.h>
19 #include <asm/barrier.h>
20 #include <asm/compiler.h>
21 #include <asm/cpu-features.h>
22 #include <asm/cmpxchg.h>
23 #include <asm/war.h>
24
25 #define ATOMIC_INIT(i) { (i) }
26
27 /*
28 * atomic_read - read atomic variable
29 * @v: pointer of type atomic_t
30 *
31 * Atomically reads the value of @v.
32 */
33 #define atomic_read(v) ACCESS_ONCE((v)->counter)
34
35 /*
36 * atomic_set - set atomic variable
37 * @v: pointer of type atomic_t
38 * @i: required value
39 *
40 * Atomically sets the value of @v to @i.
41 */
42 #define atomic_set(v, i) ((v)->counter = (i))
43
44 #define ATOMIC_OP(op, c_op, asm_op) \
45 static __inline__ void atomic_##op(int i, atomic_t * v) \
46 { \
47 if (kernel_uses_llsc && R10000_LLSC_WAR) { \
48 int temp; \
49 \
50 __asm__ __volatile__( \
51 " .set arch=r4000 \n" \
52 "1: ll %0, %1 # atomic_" #op " \n" \
53 " " #asm_op " %0, %2 \n" \
54 " sc %0, %1 \n" \
55 " beqzl %0, 1b \n" \
56 " .set mips0 \n" \
57 : "=&r" (temp), "+" GCC_OFF12_ASM() (v->counter) \
58 : "Ir" (i)); \
59 } else if (kernel_uses_llsc) { \
60 int temp; \
61 \
62 do { \
63 __asm__ __volatile__( \
64 " .set arch=r4000 \n" \
65 " ll %0, %1 # atomic_" #op "\n" \
66 " " #asm_op " %0, %2 \n" \
67 " sc %0, %1 \n" \
68 " .set mips0 \n" \
69 : "=&r" (temp), "+" GCC_OFF12_ASM() (v->counter) \
70 : "Ir" (i)); \
71 } while (unlikely(!temp)); \
72 } else { \
73 unsigned long flags; \
74 \
75 raw_local_irq_save(flags); \
76 v->counter c_op i; \
77 raw_local_irq_restore(flags); \
78 } \
79 }
80
81 #define ATOMIC_OP_RETURN(op, c_op, asm_op) \
82 static __inline__ int atomic_##op##_return(int i, atomic_t * v) \
83 { \
84 int result; \
85 \
86 smp_mb__before_llsc(); \
87 \
88 if (kernel_uses_llsc && R10000_LLSC_WAR) { \
89 int temp; \
90 \
91 __asm__ __volatile__( \
92 " .set arch=r4000 \n" \
93 "1: ll %1, %2 # atomic_" #op "_return \n" \
94 " " #asm_op " %0, %1, %3 \n" \
95 " sc %0, %2 \n" \
96 " beqzl %0, 1b \n" \
97 " " #asm_op " %0, %1, %3 \n" \
98 " .set mips0 \n" \
99 : "=&r" (result), "=&r" (temp), \
100 "+" GCC_OFF12_ASM() (v->counter) \
101 : "Ir" (i)); \
102 } else if (kernel_uses_llsc) { \
103 int temp; \
104 \
105 do { \
106 __asm__ __volatile__( \
107 " .set arch=r4000 \n" \
108 " ll %1, %2 # atomic_" #op "_return \n" \
109 " " #asm_op " %0, %1, %3 \n" \
110 " sc %0, %2 \n" \
111 " .set mips0 \n" \
112 : "=&r" (result), "=&r" (temp), \
113 "+" GCC_OFF12_ASM() (v->counter) \
114 : "Ir" (i)); \
115 } while (unlikely(!result)); \
116 \
117 result = temp; result c_op i; \
118 } else { \
119 unsigned long flags; \
120 \
121 raw_local_irq_save(flags); \
122 result = v->counter; \
123 result c_op i; \
124 v->counter = result; \
125 raw_local_irq_restore(flags); \
126 } \
127 \
128 smp_llsc_mb(); \
129 \
130 return result; \
131 }
132
133 #define ATOMIC_OPS(op, c_op, asm_op) \
134 ATOMIC_OP(op, c_op, asm_op) \
135 ATOMIC_OP_RETURN(op, c_op, asm_op)
136
137 ATOMIC_OPS(add, +=, addu)
138 ATOMIC_OPS(sub, -=, subu)
139
140 #undef ATOMIC_OPS
141 #undef ATOMIC_OP_RETURN
142 #undef ATOMIC_OP
143
144 /*
145 * atomic_sub_if_positive - conditionally subtract integer from atomic variable
146 * @i: integer value to subtract
147 * @v: pointer of type atomic_t
148 *
149 * Atomically test @v and subtract @i if @v is greater or equal than @i.
150 * The function returns the old value of @v minus @i.
151 */
152 static __inline__ int atomic_sub_if_positive(int i, atomic_t * v)
153 {
154 int result;
155
156 smp_mb__before_llsc();
157
158 if (kernel_uses_llsc && R10000_LLSC_WAR) {
159 int temp;
160
161 __asm__ __volatile__(
162 " .set arch=r4000 \n"
163 "1: ll %1, %2 # atomic_sub_if_positive\n"
164 " subu %0, %1, %3 \n"
165 " bltz %0, 1f \n"
166 " sc %0, %2 \n"
167 " .set noreorder \n"
168 " beqzl %0, 1b \n"
169 " subu %0, %1, %3 \n"
170 " .set reorder \n"
171 "1: \n"
172 " .set mips0 \n"
173 : "=&r" (result), "=&r" (temp),
174 "+" GCC_OFF12_ASM() (v->counter)
175 : "Ir" (i), GCC_OFF12_ASM() (v->counter)
176 : "memory");
177 } else if (kernel_uses_llsc) {
178 int temp;
179
180 __asm__ __volatile__(
181 " .set arch=r4000 \n"
182 "1: ll %1, %2 # atomic_sub_if_positive\n"
183 " subu %0, %1, %3 \n"
184 " bltz %0, 1f \n"
185 " sc %0, %2 \n"
186 " .set noreorder \n"
187 " beqz %0, 1b \n"
188 " subu %0, %1, %3 \n"
189 " .set reorder \n"
190 "1: \n"
191 " .set mips0 \n"
192 : "=&r" (result), "=&r" (temp),
193 "+" GCC_OFF12_ASM() (v->counter)
194 : "Ir" (i));
195 } else {
196 unsigned long flags;
197
198 raw_local_irq_save(flags);
199 result = v->counter;
200 result -= i;
201 if (result >= 0)
202 v->counter = result;
203 raw_local_irq_restore(flags);
204 }
205
206 smp_llsc_mb();
207
208 return result;
209 }
210
211 #define atomic_cmpxchg(v, o, n) (cmpxchg(&((v)->counter), (o), (n)))
212 #define atomic_xchg(v, new) (xchg(&((v)->counter), (new)))
213
214 /**
215 * __atomic_add_unless - add unless the number is a given value
216 * @v: pointer of type atomic_t
217 * @a: the amount to add to v...
218 * @u: ...unless v is equal to u.
219 *
220 * Atomically adds @a to @v, so long as it was not @u.
221 * Returns the old value of @v.
222 */
223 static __inline__ int __atomic_add_unless(atomic_t *v, int a, int u)
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;
236 }
237
238 #define atomic_dec_return(v) atomic_sub_return(1, (v))
239 #define atomic_inc_return(v) atomic_add_return(1, (v))
240
241 /*
242 * atomic_sub_and_test - subtract value from variable and test result
243 * @i: integer value to subtract
244 * @v: pointer of type atomic_t
245 *
246 * Atomically subtracts @i from @v and returns
247 * true if the result is zero, or false for all
248 * other cases.
249 */
250 #define atomic_sub_and_test(i, v) (atomic_sub_return((i), (v)) == 0)
251
252 /*
253 * atomic_inc_and_test - increment and test
254 * @v: pointer of type atomic_t
255 *
256 * Atomically increments @v by 1
257 * and returns true if the result is zero, or false for all
258 * other cases.
259 */
260 #define atomic_inc_and_test(v) (atomic_inc_return(v) == 0)
261
262 /*
263 * atomic_dec_and_test - decrement by 1 and test
264 * @v: pointer of type atomic_t
265 *
266 * Atomically decrements @v by 1 and
267 * returns true if the result is 0, or false for all other
268 * cases.
269 */
270 #define atomic_dec_and_test(v) (atomic_sub_return(1, (v)) == 0)
271
272 /*
273 * atomic_dec_if_positive - decrement by 1 if old value positive
274 * @v: pointer of type atomic_t
275 */
276 #define atomic_dec_if_positive(v) atomic_sub_if_positive(1, v)
277
278 /*
279 * atomic_inc - increment atomic variable
280 * @v: pointer of type atomic_t
281 *
282 * Atomically increments @v by 1.
283 */
284 #define atomic_inc(v) atomic_add(1, (v))
285
286 /*
287 * atomic_dec - decrement and test
288 * @v: pointer of type atomic_t
289 *
290 * Atomically decrements @v by 1.
291 */
292 #define atomic_dec(v) atomic_sub(1, (v))
293
294 /*
295 * atomic_add_negative - add and test if negative
296 * @v: pointer of type atomic_t
297 * @i: integer value to add
298 *
299 * Atomically adds @i to @v and returns true
300 * if the result is negative, or false when
301 * result is greater than or equal to zero.
302 */
303 #define atomic_add_negative(i, v) (atomic_add_return(i, (v)) < 0)
304
305 #ifdef CONFIG_64BIT
306
307 #define ATOMIC64_INIT(i) { (i) }
308
309 /*
310 * atomic64_read - read atomic variable
311 * @v: pointer of type atomic64_t
312 *
313 */
314 #define atomic64_read(v) ACCESS_ONCE((v)->counter)
315
316 /*
317 * atomic64_set - set atomic variable
318 * @v: pointer of type atomic64_t
319 * @i: required value
320 */
321 #define atomic64_set(v, i) ((v)->counter = (i))
322
323 #define ATOMIC64_OP(op, c_op, asm_op) \
324 static __inline__ void atomic64_##op(long i, atomic64_t * v) \
325 { \
326 if (kernel_uses_llsc && R10000_LLSC_WAR) { \
327 long temp; \
328 \
329 __asm__ __volatile__( \
330 " .set arch=r4000 \n" \
331 "1: lld %0, %1 # atomic64_" #op " \n" \
332 " " #asm_op " %0, %2 \n" \
333 " scd %0, %1 \n" \
334 " beqzl %0, 1b \n" \
335 " .set mips0 \n" \
336 : "=&r" (temp), "+" GCC_OFF12_ASM() (v->counter) \
337 : "Ir" (i)); \
338 } else if (kernel_uses_llsc) { \
339 long temp; \
340 \
341 do { \
342 __asm__ __volatile__( \
343 " .set arch=r4000 \n" \
344 " lld %0, %1 # atomic64_" #op "\n" \
345 " " #asm_op " %0, %2 \n" \
346 " scd %0, %1 \n" \
347 " .set mips0 \n" \
348 : "=&r" (temp), "+" GCC_OFF12_ASM() (v->counter) \
349 : "Ir" (i)); \
350 } while (unlikely(!temp)); \
351 } else { \
352 unsigned long flags; \
353 \
354 raw_local_irq_save(flags); \
355 v->counter c_op i; \
356 raw_local_irq_restore(flags); \
357 } \
358 }
359
360 #define ATOMIC64_OP_RETURN(op, c_op, asm_op) \
361 static __inline__ long atomic64_##op##_return(long i, atomic64_t * v) \
362 { \
363 long result; \
364 \
365 smp_mb__before_llsc(); \
366 \
367 if (kernel_uses_llsc && R10000_LLSC_WAR) { \
368 long temp; \
369 \
370 __asm__ __volatile__( \
371 " .set arch=r4000 \n" \
372 "1: lld %1, %2 # atomic64_" #op "_return\n" \
373 " " #asm_op " %0, %1, %3 \n" \
374 " scd %0, %2 \n" \
375 " beqzl %0, 1b \n" \
376 " " #asm_op " %0, %1, %3 \n" \
377 " .set mips0 \n" \
378 : "=&r" (result), "=&r" (temp), \
379 "+" GCC_OFF12_ASM() (v->counter) \
380 : "Ir" (i)); \
381 } else if (kernel_uses_llsc) { \
382 long temp; \
383 \
384 do { \
385 __asm__ __volatile__( \
386 " .set arch=r4000 \n" \
387 " lld %1, %2 # atomic64_" #op "_return\n" \
388 " " #asm_op " %0, %1, %3 \n" \
389 " scd %0, %2 \n" \
390 " .set mips0 \n" \
391 : "=&r" (result), "=&r" (temp), \
392 "=" GCC_OFF12_ASM() (v->counter) \
393 : "Ir" (i), GCC_OFF12_ASM() (v->counter) \
394 : "memory"); \
395 } while (unlikely(!result)); \
396 \
397 result = temp; result c_op i; \
398 } else { \
399 unsigned long flags; \
400 \
401 raw_local_irq_save(flags); \
402 result = v->counter; \
403 result c_op i; \
404 v->counter = result; \
405 raw_local_irq_restore(flags); \
406 } \
407 \
408 smp_llsc_mb(); \
409 \
410 return result; \
411 }
412
413 #define ATOMIC64_OPS(op, c_op, asm_op) \
414 ATOMIC64_OP(op, c_op, asm_op) \
415 ATOMIC64_OP_RETURN(op, c_op, asm_op)
416
417 ATOMIC64_OPS(add, +=, daddu)
418 ATOMIC64_OPS(sub, -=, dsubu)
419
420 #undef ATOMIC64_OPS
421 #undef ATOMIC64_OP_RETURN
422 #undef ATOMIC64_OP
423
424 /*
425 * atomic64_sub_if_positive - conditionally subtract integer from atomic
426 * variable
427 * @i: integer value to subtract
428 * @v: pointer of type atomic64_t
429 *
430 * Atomically test @v and subtract @i if @v is greater or equal than @i.
431 * The function returns the old value of @v minus @i.
432 */
433 static __inline__ long atomic64_sub_if_positive(long i, atomic64_t * v)
434 {
435 long result;
436
437 smp_mb__before_llsc();
438
439 if (kernel_uses_llsc && R10000_LLSC_WAR) {
440 long temp;
441
442 __asm__ __volatile__(
443 " .set arch=r4000 \n"
444 "1: lld %1, %2 # atomic64_sub_if_positive\n"
445 " dsubu %0, %1, %3 \n"
446 " bltz %0, 1f \n"
447 " scd %0, %2 \n"
448 " .set noreorder \n"
449 " beqzl %0, 1b \n"
450 " dsubu %0, %1, %3 \n"
451 " .set reorder \n"
452 "1: \n"
453 " .set mips0 \n"
454 : "=&r" (result), "=&r" (temp),
455 "=" GCC_OFF12_ASM() (v->counter)
456 : "Ir" (i), GCC_OFF12_ASM() (v->counter)
457 : "memory");
458 } else if (kernel_uses_llsc) {
459 long temp;
460
461 __asm__ __volatile__(
462 " .set arch=r4000 \n"
463 "1: lld %1, %2 # atomic64_sub_if_positive\n"
464 " dsubu %0, %1, %3 \n"
465 " bltz %0, 1f \n"
466 " scd %0, %2 \n"
467 " .set noreorder \n"
468 " beqz %0, 1b \n"
469 " dsubu %0, %1, %3 \n"
470 " .set reorder \n"
471 "1: \n"
472 " .set mips0 \n"
473 : "=&r" (result), "=&r" (temp),
474 "+" GCC_OFF12_ASM() (v->counter)
475 : "Ir" (i));
476 } else {
477 unsigned long flags;
478
479 raw_local_irq_save(flags);
480 result = v->counter;
481 result -= i;
482 if (result >= 0)
483 v->counter = result;
484 raw_local_irq_restore(flags);
485 }
486
487 smp_llsc_mb();
488
489 return result;
490 }
491
492 #define atomic64_cmpxchg(v, o, n) \
493 ((__typeof__((v)->counter))cmpxchg(&((v)->counter), (o), (n)))
494 #define atomic64_xchg(v, new) (xchg(&((v)->counter), (new)))
495
496 /**
497 * atomic64_add_unless - add unless the number is a given value
498 * @v: pointer of type atomic64_t
499 * @a: the amount to add to v...
500 * @u: ...unless v is equal to u.
501 *
502 * Atomically adds @a to @v, so long as it was not @u.
503 * Returns the old value of @v.
504 */
505 static __inline__ int atomic64_add_unless(atomic64_t *v, long a, long u)
506 {
507 long c, old;
508 c = atomic64_read(v);
509 for (;;) {
510 if (unlikely(c == (u)))
511 break;
512 old = atomic64_cmpxchg((v), c, c + (a));
513 if (likely(old == c))
514 break;
515 c = old;
516 }
517 return c != (u);
518 }
519
520 #define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0)
521
522 #define atomic64_dec_return(v) atomic64_sub_return(1, (v))
523 #define atomic64_inc_return(v) atomic64_add_return(1, (v))
524
525 /*
526 * atomic64_sub_and_test - subtract value from variable and test result
527 * @i: integer value to subtract
528 * @v: pointer of type atomic64_t
529 *
530 * Atomically subtracts @i from @v and returns
531 * true if the result is zero, or false for all
532 * other cases.
533 */
534 #define atomic64_sub_and_test(i, v) (atomic64_sub_return((i), (v)) == 0)
535
536 /*
537 * atomic64_inc_and_test - increment and test
538 * @v: pointer of type atomic64_t
539 *
540 * Atomically increments @v by 1
541 * and returns true if the result is zero, or false for all
542 * other cases.
543 */
544 #define atomic64_inc_and_test(v) (atomic64_inc_return(v) == 0)
545
546 /*
547 * atomic64_dec_and_test - decrement by 1 and test
548 * @v: pointer of type atomic64_t
549 *
550 * Atomically decrements @v by 1 and
551 * returns true if the result is 0, or false for all other
552 * cases.
553 */
554 #define atomic64_dec_and_test(v) (atomic64_sub_return(1, (v)) == 0)
555
556 /*
557 * atomic64_dec_if_positive - decrement by 1 if old value positive
558 * @v: pointer of type atomic64_t
559 */
560 #define atomic64_dec_if_positive(v) atomic64_sub_if_positive(1, v)
561
562 /*
563 * atomic64_inc - increment atomic variable
564 * @v: pointer of type atomic64_t
565 *
566 * Atomically increments @v by 1.
567 */
568 #define atomic64_inc(v) atomic64_add(1, (v))
569
570 /*
571 * atomic64_dec - decrement and test
572 * @v: pointer of type atomic64_t
573 *
574 * Atomically decrements @v by 1.
575 */
576 #define atomic64_dec(v) atomic64_sub(1, (v))
577
578 /*
579 * atomic64_add_negative - add and test if negative
580 * @v: pointer of type atomic64_t
581 * @i: integer value to add
582 *
583 * Atomically adds @i to @v and returns true
584 * if the result is negative, or false when
585 * result is greater than or equal to zero.
586 */
587 #define atomic64_add_negative(i, v) (atomic64_add_return(i, (v)) < 0)
588
589 #endif /* CONFIG_64BIT */
590
591 #endif /* _ASM_ATOMIC_H */
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