1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3 * arch/arm/include/asm/atomic.h
4 *
5 * Copyright (C) 1996 Russell King.
6 * Copyright (C) 2002 Deep Blue Solutions Ltd.
7 */
8 #ifndef __ASM_ARM_ATOMIC_H
9 #define __ASM_ARM_ATOMIC_H
10
11 #include <linux/compiler.h>
12 #include <linux/prefetch.h>
13 #include <linux/types.h>
14 #include <linux/irqflags.h>
15 #include <asm/barrier.h>
16 #include <asm/cmpxchg.h>
17
18 #ifdef __KERNEL__
19
20 /*
21 * On ARM, ordinary assignment (str instruction) doesn't clear the local
22 * strex/ldrex monitor on some implementations. The reason we can use it for
23 * atomic_set() is the clrex or dummy strex done on every exception return.
24 */
25 #define atomic_read(v) READ_ONCE((v)->counter)
26 #define atomic_set(v,i) WRITE_ONCE(((v)->counter), (i))
27
28 #if __LINUX_ARM_ARCH__ >= 6
29
30 /*
31 * ARMv6 UP and SMP safe atomic ops. We use load exclusive and
32 * store exclusive to ensure that these are atomic. We may loop
33 * to ensure that the update happens.
34 */
35
36 #define ATOMIC_OP(op, c_op, asm_op) \
37 static inline void atomic_##op(int i, atomic_t *v) \
38 { \
39 unsigned long tmp; \
40 int result; \
41 \
42 prefetchw(&v->counter); \
43 __asm__ __volatile__("@ atomic_" #op "\n" \
44 "1: ldrex %0, [%3]\n" \
45 " " #asm_op " %0, %0, %4\n" \
46 " strex %1, %0, [%3]\n" \
47 " teq %1, #0\n" \
48 " bne 1b" \
49 : "=&r" (result), "=&r" (tmp), "+Qo" (v->counter) \
50 : "r" (&v->counter), "Ir" (i) \
51 : "cc"); \
52 } \
53
54 #define ATOMIC_OP_RETURN(op, c_op, asm_op) \
55 static inline int atomic_##op##_return_relaxed(int i, atomic_t *v) \
56 { \
57 unsigned long tmp; \
58 int result; \
59 \
60 prefetchw(&v->counter); \
61 \
62 __asm__ __volatile__("@ atomic_" #op "_return\n" \
63 "1: ldrex %0, [%3]\n" \
64 " " #asm_op " %0, %0, %4\n" \
65 " strex %1, %0, [%3]\n" \
66 " teq %1, #0\n" \
67 " bne 1b" \
68 : "=&r" (result), "=&r" (tmp), "+Qo" (v->counter) \
69 : "r" (&v->counter), "Ir" (i) \
70 : "cc"); \
71 \
72 return result; \
73 }
74
75 #define ATOMIC_FETCH_OP(op, c_op, asm_op) \
76 static inline int atomic_fetch_##op##_relaxed(int i, atomic_t *v) \
77 { \
78 unsigned long tmp; \
79 int result, val; \
80 \
81 prefetchw(&v->counter); \
82 \
83 __asm__ __volatile__("@ atomic_fetch_" #op "\n" \
84 "1: ldrex %0, [%4]\n" \
85 " " #asm_op " %1, %0, %5\n" \
86 " strex %2, %1, [%4]\n" \
87 " teq %2, #0\n" \
88 " bne 1b" \
89 : "=&r" (result), "=&r" (val), "=&r" (tmp), "+Qo" (v->counter) \
90 : "r" (&v->counter), "Ir" (i) \
91 : "cc"); \
92 \
93 return result; \
94 }
95
96 #define atomic_add_return_relaxed atomic_add_return_relaxed
97 #define atomic_sub_return_relaxed atomic_sub_return_relaxed
98 #define atomic_fetch_add_relaxed atomic_fetch_add_relaxed
99 #define atomic_fetch_sub_relaxed atomic_fetch_sub_relaxed
100
101 #define atomic_fetch_and_relaxed atomic_fetch_and_relaxed
102 #define atomic_fetch_andnot_relaxed atomic_fetch_andnot_relaxed
103 #define atomic_fetch_or_relaxed atomic_fetch_or_relaxed
104 #define atomic_fetch_xor_relaxed atomic_fetch_xor_relaxed
105
atomic_cmpxchg_relaxed(atomic_t * ptr,int old,int new)106 static inline int atomic_cmpxchg_relaxed(atomic_t *ptr, int old, int new)
107 {
108 int oldval;
109 unsigned long res;
110
111 prefetchw(&ptr->counter);
112
113 do {
114 __asm__ __volatile__("@ atomic_cmpxchg\n"
115 "ldrex %1, [%3]\n"
116 "mov %0, #0\n"
117 "teq %1, %4\n"
118 "strexeq %0, %5, [%3]\n"
119 : "=&r" (res), "=&r" (oldval), "+Qo" (ptr->counter)
120 : "r" (&ptr->counter), "Ir" (old), "r" (new)
121 : "cc");
122 } while (res);
123
124 return oldval;
125 }
126 #define atomic_cmpxchg_relaxed atomic_cmpxchg_relaxed
127
atomic_fetch_add_unless(atomic_t * v,int a,int u)128 static inline int atomic_fetch_add_unless(atomic_t *v, int a, int u)
129 {
130 int oldval, newval;
131 unsigned long tmp;
132
133 smp_mb();
134 prefetchw(&v->counter);
135
136 __asm__ __volatile__ ("@ atomic_add_unless\n"
137 "1: ldrex %0, [%4]\n"
138 " teq %0, %5\n"
139 " beq 2f\n"
140 " add %1, %0, %6\n"
141 " strex %2, %1, [%4]\n"
142 " teq %2, #0\n"
143 " bne 1b\n"
144 "2:"
145 : "=&r" (oldval), "=&r" (newval), "=&r" (tmp), "+Qo" (v->counter)
146 : "r" (&v->counter), "r" (u), "r" (a)
147 : "cc");
148
149 if (oldval != u)
150 smp_mb();
151
152 return oldval;
153 }
154 #define atomic_fetch_add_unless atomic_fetch_add_unless
155
156 #else /* ARM_ARCH_6 */
157
158 #ifdef CONFIG_SMP
159 #error SMP not supported on pre-ARMv6 CPUs
160 #endif
161
162 #define ATOMIC_OP(op, c_op, asm_op) \
163 static inline void atomic_##op(int i, atomic_t *v) \
164 { \
165 unsigned long flags; \
166 \
167 raw_local_irq_save(flags); \
168 v->counter c_op i; \
169 raw_local_irq_restore(flags); \
170 } \
171
172 #define ATOMIC_OP_RETURN(op, c_op, asm_op) \
173 static inline int atomic_##op##_return(int i, atomic_t *v) \
174 { \
175 unsigned long flags; \
176 int val; \
177 \
178 raw_local_irq_save(flags); \
179 v->counter c_op i; \
180 val = v->counter; \
181 raw_local_irq_restore(flags); \
182 \
183 return val; \
184 }
185
186 #define ATOMIC_FETCH_OP(op, c_op, asm_op) \
187 static inline int atomic_fetch_##op(int i, atomic_t *v) \
188 { \
189 unsigned long flags; \
190 int val; \
191 \
192 raw_local_irq_save(flags); \
193 val = v->counter; \
194 v->counter c_op i; \
195 raw_local_irq_restore(flags); \
196 \
197 return val; \
198 }
199
atomic_cmpxchg(atomic_t * v,int old,int new)200 static inline int atomic_cmpxchg(atomic_t *v, int old, int new)
201 {
202 int ret;
203 unsigned long flags;
204
205 raw_local_irq_save(flags);
206 ret = v->counter;
207 if (likely(ret == old))
208 v->counter = new;
209 raw_local_irq_restore(flags);
210
211 return ret;
212 }
213
214 #define atomic_fetch_andnot atomic_fetch_andnot
215
216 #endif /* __LINUX_ARM_ARCH__ */
217
218 #define ATOMIC_OPS(op, c_op, asm_op) \
219 ATOMIC_OP(op, c_op, asm_op) \
220 ATOMIC_OP_RETURN(op, c_op, asm_op) \
221 ATOMIC_FETCH_OP(op, c_op, asm_op)
222
223 ATOMIC_OPS(add, +=, add)
224 ATOMIC_OPS(sub, -=, sub)
225
226 #define atomic_andnot atomic_andnot
227
228 #undef ATOMIC_OPS
229 #define ATOMIC_OPS(op, c_op, asm_op) \
230 ATOMIC_OP(op, c_op, asm_op) \
231 ATOMIC_FETCH_OP(op, c_op, asm_op)
232
233 ATOMIC_OPS(and, &=, and)
234 ATOMIC_OPS(andnot, &= ~, bic)
235 ATOMIC_OPS(or, |=, orr)
236 ATOMIC_OPS(xor, ^=, eor)
237
238 #undef ATOMIC_OPS
239 #undef ATOMIC_FETCH_OP
240 #undef ATOMIC_OP_RETURN
241 #undef ATOMIC_OP
242
243 #define atomic_xchg(v, new) (xchg(&((v)->counter), new))
244
245 #ifndef CONFIG_GENERIC_ATOMIC64
246 typedef struct {
247 s64 counter;
248 } atomic64_t;
249
250 #define ATOMIC64_INIT(i) { (i) }
251
252 #ifdef CONFIG_ARM_LPAE
atomic64_read(const atomic64_t * v)253 static inline s64 atomic64_read(const atomic64_t *v)
254 {
255 s64 result;
256
257 __asm__ __volatile__("@ atomic64_read\n"
258 " ldrd %0, %H0, [%1]"
259 : "=&r" (result)
260 : "r" (&v->counter), "Qo" (v->counter)
261 );
262
263 return result;
264 }
265
atomic64_set(atomic64_t * v,s64 i)266 static inline void atomic64_set(atomic64_t *v, s64 i)
267 {
268 __asm__ __volatile__("@ atomic64_set\n"
269 " strd %2, %H2, [%1]"
270 : "=Qo" (v->counter)
271 : "r" (&v->counter), "r" (i)
272 );
273 }
274 #else
atomic64_read(const atomic64_t * v)275 static inline s64 atomic64_read(const atomic64_t *v)
276 {
277 s64 result;
278
279 __asm__ __volatile__("@ atomic64_read\n"
280 " ldrexd %0, %H0, [%1]"
281 : "=&r" (result)
282 : "r" (&v->counter), "Qo" (v->counter)
283 );
284
285 return result;
286 }
287
atomic64_set(atomic64_t * v,s64 i)288 static inline void atomic64_set(atomic64_t *v, s64 i)
289 {
290 s64 tmp;
291
292 prefetchw(&v->counter);
293 __asm__ __volatile__("@ atomic64_set\n"
294 "1: ldrexd %0, %H0, [%2]\n"
295 " strexd %0, %3, %H3, [%2]\n"
296 " teq %0, #0\n"
297 " bne 1b"
298 : "=&r" (tmp), "=Qo" (v->counter)
299 : "r" (&v->counter), "r" (i)
300 : "cc");
301 }
302 #endif
303
304 #define ATOMIC64_OP(op, op1, op2) \
305 static inline void atomic64_##op(s64 i, atomic64_t *v) \
306 { \
307 s64 result; \
308 unsigned long tmp; \
309 \
310 prefetchw(&v->counter); \
311 __asm__ __volatile__("@ atomic64_" #op "\n" \
312 "1: ldrexd %0, %H0, [%3]\n" \
313 " " #op1 " %Q0, %Q0, %Q4\n" \
314 " " #op2 " %R0, %R0, %R4\n" \
315 " strexd %1, %0, %H0, [%3]\n" \
316 " teq %1, #0\n" \
317 " bne 1b" \
318 : "=&r" (result), "=&r" (tmp), "+Qo" (v->counter) \
319 : "r" (&v->counter), "r" (i) \
320 : "cc"); \
321 } \
322
323 #define ATOMIC64_OP_RETURN(op, op1, op2) \
324 static inline s64 \
325 atomic64_##op##_return_relaxed(s64 i, atomic64_t *v) \
326 { \
327 s64 result; \
328 unsigned long tmp; \
329 \
330 prefetchw(&v->counter); \
331 \
332 __asm__ __volatile__("@ atomic64_" #op "_return\n" \
333 "1: ldrexd %0, %H0, [%3]\n" \
334 " " #op1 " %Q0, %Q0, %Q4\n" \
335 " " #op2 " %R0, %R0, %R4\n" \
336 " strexd %1, %0, %H0, [%3]\n" \
337 " teq %1, #0\n" \
338 " bne 1b" \
339 : "=&r" (result), "=&r" (tmp), "+Qo" (v->counter) \
340 : "r" (&v->counter), "r" (i) \
341 : "cc"); \
342 \
343 return result; \
344 }
345
346 #define ATOMIC64_FETCH_OP(op, op1, op2) \
347 static inline s64 \
348 atomic64_fetch_##op##_relaxed(s64 i, atomic64_t *v) \
349 { \
350 s64 result, val; \
351 unsigned long tmp; \
352 \
353 prefetchw(&v->counter); \
354 \
355 __asm__ __volatile__("@ atomic64_fetch_" #op "\n" \
356 "1: ldrexd %0, %H0, [%4]\n" \
357 " " #op1 " %Q1, %Q0, %Q5\n" \
358 " " #op2 " %R1, %R0, %R5\n" \
359 " strexd %2, %1, %H1, [%4]\n" \
360 " teq %2, #0\n" \
361 " bne 1b" \
362 : "=&r" (result), "=&r" (val), "=&r" (tmp), "+Qo" (v->counter) \
363 : "r" (&v->counter), "r" (i) \
364 : "cc"); \
365 \
366 return result; \
367 }
368
369 #define ATOMIC64_OPS(op, op1, op2) \
370 ATOMIC64_OP(op, op1, op2) \
371 ATOMIC64_OP_RETURN(op, op1, op2) \
372 ATOMIC64_FETCH_OP(op, op1, op2)
373
ATOMIC64_OPS(add,adds,adc)374 ATOMIC64_OPS(add, adds, adc)
375 ATOMIC64_OPS(sub, subs, sbc)
376
377 #define atomic64_add_return_relaxed atomic64_add_return_relaxed
378 #define atomic64_sub_return_relaxed atomic64_sub_return_relaxed
379 #define atomic64_fetch_add_relaxed atomic64_fetch_add_relaxed
380 #define atomic64_fetch_sub_relaxed atomic64_fetch_sub_relaxed
381
382 #undef ATOMIC64_OPS
383 #define ATOMIC64_OPS(op, op1, op2) \
384 ATOMIC64_OP(op, op1, op2) \
385 ATOMIC64_FETCH_OP(op, op1, op2)
386
387 #define atomic64_andnot atomic64_andnot
388
389 ATOMIC64_OPS(and, and, and)
390 ATOMIC64_OPS(andnot, bic, bic)
391 ATOMIC64_OPS(or, orr, orr)
392 ATOMIC64_OPS(xor, eor, eor)
393
394 #define atomic64_fetch_and_relaxed atomic64_fetch_and_relaxed
395 #define atomic64_fetch_andnot_relaxed atomic64_fetch_andnot_relaxed
396 #define atomic64_fetch_or_relaxed atomic64_fetch_or_relaxed
397 #define atomic64_fetch_xor_relaxed atomic64_fetch_xor_relaxed
398
399 #undef ATOMIC64_OPS
400 #undef ATOMIC64_FETCH_OP
401 #undef ATOMIC64_OP_RETURN
402 #undef ATOMIC64_OP
403
404 static inline s64 atomic64_cmpxchg_relaxed(atomic64_t *ptr, s64 old, s64 new)
405 {
406 s64 oldval;
407 unsigned long res;
408
409 prefetchw(&ptr->counter);
410
411 do {
412 __asm__ __volatile__("@ atomic64_cmpxchg\n"
413 "ldrexd %1, %H1, [%3]\n"
414 "mov %0, #0\n"
415 "teq %1, %4\n"
416 "teqeq %H1, %H4\n"
417 "strexdeq %0, %5, %H5, [%3]"
418 : "=&r" (res), "=&r" (oldval), "+Qo" (ptr->counter)
419 : "r" (&ptr->counter), "r" (old), "r" (new)
420 : "cc");
421 } while (res);
422
423 return oldval;
424 }
425 #define atomic64_cmpxchg_relaxed atomic64_cmpxchg_relaxed
426
atomic64_xchg_relaxed(atomic64_t * ptr,s64 new)427 static inline s64 atomic64_xchg_relaxed(atomic64_t *ptr, s64 new)
428 {
429 s64 result;
430 unsigned long tmp;
431
432 prefetchw(&ptr->counter);
433
434 __asm__ __volatile__("@ atomic64_xchg\n"
435 "1: ldrexd %0, %H0, [%3]\n"
436 " strexd %1, %4, %H4, [%3]\n"
437 " teq %1, #0\n"
438 " bne 1b"
439 : "=&r" (result), "=&r" (tmp), "+Qo" (ptr->counter)
440 : "r" (&ptr->counter), "r" (new)
441 : "cc");
442
443 return result;
444 }
445 #define atomic64_xchg_relaxed atomic64_xchg_relaxed
446
atomic64_dec_if_positive(atomic64_t * v)447 static inline s64 atomic64_dec_if_positive(atomic64_t *v)
448 {
449 s64 result;
450 unsigned long tmp;
451
452 smp_mb();
453 prefetchw(&v->counter);
454
455 __asm__ __volatile__("@ atomic64_dec_if_positive\n"
456 "1: ldrexd %0, %H0, [%3]\n"
457 " subs %Q0, %Q0, #1\n"
458 " sbc %R0, %R0, #0\n"
459 " teq %R0, #0\n"
460 " bmi 2f\n"
461 " strexd %1, %0, %H0, [%3]\n"
462 " teq %1, #0\n"
463 " bne 1b\n"
464 "2:"
465 : "=&r" (result), "=&r" (tmp), "+Qo" (v->counter)
466 : "r" (&v->counter)
467 : "cc");
468
469 smp_mb();
470
471 return result;
472 }
473 #define atomic64_dec_if_positive atomic64_dec_if_positive
474
atomic64_fetch_add_unless(atomic64_t * v,s64 a,s64 u)475 static inline s64 atomic64_fetch_add_unless(atomic64_t *v, s64 a, s64 u)
476 {
477 s64 oldval, newval;
478 unsigned long tmp;
479
480 smp_mb();
481 prefetchw(&v->counter);
482
483 __asm__ __volatile__("@ atomic64_add_unless\n"
484 "1: ldrexd %0, %H0, [%4]\n"
485 " teq %0, %5\n"
486 " teqeq %H0, %H5\n"
487 " beq 2f\n"
488 " adds %Q1, %Q0, %Q6\n"
489 " adc %R1, %R0, %R6\n"
490 " strexd %2, %1, %H1, [%4]\n"
491 " teq %2, #0\n"
492 " bne 1b\n"
493 "2:"
494 : "=&r" (oldval), "=&r" (newval), "=&r" (tmp), "+Qo" (v->counter)
495 : "r" (&v->counter), "r" (u), "r" (a)
496 : "cc");
497
498 if (oldval != u)
499 smp_mb();
500
501 return oldval;
502 }
503 #define atomic64_fetch_add_unless atomic64_fetch_add_unless
504
505 #endif /* !CONFIG_GENERIC_ATOMIC64 */
506 #endif
507 #endif
508
