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 /*
26 * Using a branch-likely instruction to check the result of an sc instruction
27 * works around a bug present in R10000 CPUs prior to revision 3.0 that could
28 * cause ll-sc sequences to execute non-atomically.
29 */
30 #if R10000_LLSC_WAR
31 # define __scbeqz "beqzl"
32 #else
33 # define __scbeqz "beqz"
34 #endif
35
36 #define ATOMIC_INIT(i) { (i) }
37
38 /*
39 * atomic_read - read atomic variable
40 * @v: pointer of type atomic_t
41 *
42 * Atomically reads the value of @v.
43 */
44 #define atomic_read(v) READ_ONCE((v)->counter)
45
46 /*
47 * atomic_set - set atomic variable
48 * @v: pointer of type atomic_t
49 * @i: required value
50 *
51 * Atomically sets the value of @v to @i.
52 */
53 #define atomic_set(v, i) WRITE_ONCE((v)->counter, (i))
54
55 #define ATOMIC_OP(op, c_op, asm_op) \
56 static __inline__ void atomic_##op(int i, atomic_t * v) \
57 { \
58 if (kernel_uses_llsc) { \
59 int temp; \
60 \
61 loongson_llsc_mb(); \
62 __asm__ __volatile__( \
63 " .set push \n" \
64 " .set "MIPS_ISA_LEVEL" \n" \
65 "1: ll %0, %1 # atomic_" #op " \n" \
66 " " #asm_op " %0, %2 \n" \
67 " sc %0, %1 \n" \
68 "\t" __scbeqz " %0, 1b \n" \
69 " .set pop \n" \
70 : "=&r" (temp), "+" GCC_OFF_SMALL_ASM() (v->counter) \
71 : "Ir" (i) : __LLSC_CLOBBER); \
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_relaxed(int i, atomic_t * v) \
83 { \
84 int result; \
85 \
86 if (kernel_uses_llsc) { \
87 int temp; \
88 \
89 loongson_llsc_mb(); \
90 __asm__ __volatile__( \
91 " .set push \n" \
92 " .set "MIPS_ISA_LEVEL" \n" \
93 "1: ll %1, %2 # atomic_" #op "_return \n" \
94 " " #asm_op " %0, %1, %3 \n" \
95 " sc %0, %2 \n" \
96 "\t" __scbeqz " %0, 1b \n" \
97 " " #asm_op " %0, %1, %3 \n" \
98 " .set pop \n" \
99 : "=&r" (result), "=&r" (temp), \
100 "+" GCC_OFF_SMALL_ASM() (v->counter) \
101 : "Ir" (i) : __LLSC_CLOBBER); \
102 } else { \
103 unsigned long flags; \
104 \
105 raw_local_irq_save(flags); \
106 result = v->counter; \
107 result c_op i; \
108 v->counter = result; \
109 raw_local_irq_restore(flags); \
110 } \
111 \
112 return result; \
113 }
114
115 #define ATOMIC_FETCH_OP(op, c_op, asm_op) \
116 static __inline__ int atomic_fetch_##op##_relaxed(int i, atomic_t * v) \
117 { \
118 int result; \
119 \
120 if (kernel_uses_llsc) { \
121 int temp; \
122 \
123 loongson_llsc_mb(); \
124 __asm__ __volatile__( \
125 " .set push \n" \
126 " .set "MIPS_ISA_LEVEL" \n" \
127 "1: ll %1, %2 # atomic_fetch_" #op " \n" \
128 " " #asm_op " %0, %1, %3 \n" \
129 " sc %0, %2 \n" \
130 "\t" __scbeqz " %0, 1b \n" \
131 " .set pop \n" \
132 " move %0, %1 \n" \
133 : "=&r" (result), "=&r" (temp), \
134 "+" GCC_OFF_SMALL_ASM() (v->counter) \
135 : "Ir" (i) : __LLSC_CLOBBER); \
136 } else { \
137 unsigned long flags; \
138 \
139 raw_local_irq_save(flags); \
140 result = v->counter; \
141 v->counter c_op i; \
142 raw_local_irq_restore(flags); \
143 } \
144 \
145 return result; \
146 }
147
148 #define ATOMIC_OPS(op, c_op, asm_op) \
149 ATOMIC_OP(op, c_op, asm_op) \
150 ATOMIC_OP_RETURN(op, c_op, asm_op) \
151 ATOMIC_FETCH_OP(op, c_op, asm_op)
152
153 ATOMIC_OPS(add, +=, addu)
154 ATOMIC_OPS(sub, -=, subu)
155
156 #define atomic_add_return_relaxed atomic_add_return_relaxed
157 #define atomic_sub_return_relaxed atomic_sub_return_relaxed
158 #define atomic_fetch_add_relaxed atomic_fetch_add_relaxed
159 #define atomic_fetch_sub_relaxed atomic_fetch_sub_relaxed
160
161 #undef ATOMIC_OPS
162 #define ATOMIC_OPS(op, c_op, asm_op) \
163 ATOMIC_OP(op, c_op, asm_op) \
164 ATOMIC_FETCH_OP(op, c_op, asm_op)
165
166 ATOMIC_OPS(and, &=, and)
167 ATOMIC_OPS(or, |=, or)
168 ATOMIC_OPS(xor, ^=, xor)
169
170 #define atomic_fetch_and_relaxed atomic_fetch_and_relaxed
171 #define atomic_fetch_or_relaxed atomic_fetch_or_relaxed
172 #define atomic_fetch_xor_relaxed atomic_fetch_xor_relaxed
173
174 #undef ATOMIC_OPS
175 #undef ATOMIC_FETCH_OP
176 #undef ATOMIC_OP_RETURN
177 #undef ATOMIC_OP
178
179 /*
180 * atomic_sub_if_positive - conditionally subtract integer from atomic variable
181 * @i: integer value to subtract
182 * @v: pointer of type atomic_t
183 *
184 * Atomically test @v and subtract @i if @v is greater or equal than @i.
185 * The function returns the old value of @v minus @i.
186 */
187 static __inline__ int atomic_sub_if_positive(int i, atomic_t * v)
188 {
189 int result;
190
191 smp_mb__before_llsc();
192
193 if (kernel_uses_llsc) {
194 int temp;
195
196 loongson_llsc_mb();
197 __asm__ __volatile__(
198 " .set push \n"
199 " .set "MIPS_ISA_LEVEL" \n"
200 "1: ll %1, %2 # atomic_sub_if_positive\n"
201 " .set pop \n"
202 " subu %0, %1, %3 \n"
203 " move %1, %0 \n"
204 " bltz %0, 2f \n"
205 " .set push \n"
206 " .set "MIPS_ISA_LEVEL" \n"
207 " sc %1, %2 \n"
208 "\t" __scbeqz " %1, 1b \n"
209 "2: \n"
210 " .set pop \n"
211 : "=&r" (result), "=&r" (temp),
212 "+" GCC_OFF_SMALL_ASM() (v->counter)
213 : "Ir" (i) : __LLSC_CLOBBER);
214 } else {
215 unsigned long flags;
216
217 raw_local_irq_save(flags);
218 result = v->counter;
219 result -= i;
220 if (result >= 0)
221 v->counter = result;
222 raw_local_irq_restore(flags);
223 }
224
225 smp_llsc_mb();
226
227 return result;
228 }
229
230 #define atomic_cmpxchg(v, o, n) (cmpxchg(&((v)->counter), (o), (n)))
231 #define atomic_xchg(v, new) (xchg(&((v)->counter), (new)))
232
233 /*
234 * atomic_dec_if_positive - decrement by 1 if old value positive
235 * @v: pointer of type atomic_t
236 */
237 #define atomic_dec_if_positive(v) atomic_sub_if_positive(1, v)
238
239 #ifdef CONFIG_64BIT
240
241 #define ATOMIC64_INIT(i) { (i) }
242
243 /*
244 * atomic64_read - read atomic variable
245 * @v: pointer of type atomic64_t
246 *
247 */
248 #define atomic64_read(v) READ_ONCE((v)->counter)
249
250 /*
251 * atomic64_set - set atomic variable
252 * @v: pointer of type atomic64_t
253 * @i: required value
254 */
255 #define atomic64_set(v, i) WRITE_ONCE((v)->counter, (i))
256
257 #define ATOMIC64_OP(op, c_op, asm_op) \
258 static __inline__ void atomic64_##op(s64 i, atomic64_t * v) \
259 { \
260 if (kernel_uses_llsc) { \
261 s64 temp; \
262 \
263 loongson_llsc_mb(); \
264 __asm__ __volatile__( \
265 " .set push \n" \
266 " .set "MIPS_ISA_LEVEL" \n" \
267 "1: lld %0, %1 # atomic64_" #op " \n" \
268 " " #asm_op " %0, %2 \n" \
269 " scd %0, %1 \n" \
270 "\t" __scbeqz " %0, 1b \n" \
271 " .set pop \n" \
272 : "=&r" (temp), "+" GCC_OFF_SMALL_ASM() (v->counter) \
273 : "Ir" (i) : __LLSC_CLOBBER); \
274 } else { \
275 unsigned long flags; \
276 \
277 raw_local_irq_save(flags); \
278 v->counter c_op i; \
279 raw_local_irq_restore(flags); \
280 } \
281 }
282
283 #define ATOMIC64_OP_RETURN(op, c_op, asm_op) \
284 static __inline__ s64 atomic64_##op##_return_relaxed(s64 i, atomic64_t * v) \
285 { \
286 s64 result; \
287 \
288 if (kernel_uses_llsc) { \
289 s64 temp; \
290 \
291 loongson_llsc_mb(); \
292 __asm__ __volatile__( \
293 " .set push \n" \
294 " .set "MIPS_ISA_LEVEL" \n" \
295 "1: lld %1, %2 # atomic64_" #op "_return\n" \
296 " " #asm_op " %0, %1, %3 \n" \
297 " scd %0, %2 \n" \
298 "\t" __scbeqz " %0, 1b \n" \
299 " " #asm_op " %0, %1, %3 \n" \
300 " .set pop \n" \
301 : "=&r" (result), "=&r" (temp), \
302 "+" GCC_OFF_SMALL_ASM() (v->counter) \
303 : "Ir" (i) : __LLSC_CLOBBER); \
304 } else { \
305 unsigned long flags; \
306 \
307 raw_local_irq_save(flags); \
308 result = v->counter; \
309 result c_op i; \
310 v->counter = result; \
311 raw_local_irq_restore(flags); \
312 } \
313 \
314 return result; \
315 }
316
317 #define ATOMIC64_FETCH_OP(op, c_op, asm_op) \
318 static __inline__ s64 atomic64_fetch_##op##_relaxed(s64 i, atomic64_t * v) \
319 { \
320 s64 result; \
321 \
322 if (kernel_uses_llsc) { \
323 s64 temp; \
324 \
325 loongson_llsc_mb(); \
326 __asm__ __volatile__( \
327 " .set push \n" \
328 " .set "MIPS_ISA_LEVEL" \n" \
329 "1: lld %1, %2 # atomic64_fetch_" #op "\n" \
330 " " #asm_op " %0, %1, %3 \n" \
331 " scd %0, %2 \n" \
332 "\t" __scbeqz " %0, 1b \n" \
333 " move %0, %1 \n" \
334 " .set pop \n" \
335 : "=&r" (result), "=&r" (temp), \
336 "+" GCC_OFF_SMALL_ASM() (v->counter) \
337 : "Ir" (i) : __LLSC_CLOBBER); \
338 } else { \
339 unsigned long flags; \
340 \
341 raw_local_irq_save(flags); \
342 result = v->counter; \
343 v->counter c_op i; \
344 raw_local_irq_restore(flags); \
345 } \
346 \
347 return result; \
348 }
349
350 #define ATOMIC64_OPS(op, c_op, asm_op) \
351 ATOMIC64_OP(op, c_op, asm_op) \
352 ATOMIC64_OP_RETURN(op, c_op, asm_op) \
353 ATOMIC64_FETCH_OP(op, c_op, asm_op)
354
355 ATOMIC64_OPS(add, +=, daddu)
356 ATOMIC64_OPS(sub, -=, dsubu)
357
358 #define atomic64_add_return_relaxed atomic64_add_return_relaxed
359 #define atomic64_sub_return_relaxed atomic64_sub_return_relaxed
360 #define atomic64_fetch_add_relaxed atomic64_fetch_add_relaxed
361 #define atomic64_fetch_sub_relaxed atomic64_fetch_sub_relaxed
362
363 #undef ATOMIC64_OPS
364 #define ATOMIC64_OPS(op, c_op, asm_op) \
365 ATOMIC64_OP(op, c_op, asm_op) \
366 ATOMIC64_FETCH_OP(op, c_op, asm_op)
367
368 ATOMIC64_OPS(and, &=, and)
369 ATOMIC64_OPS(or, |=, or)
370 ATOMIC64_OPS(xor, ^=, xor)
371
372 #define atomic64_fetch_and_relaxed atomic64_fetch_and_relaxed
373 #define atomic64_fetch_or_relaxed atomic64_fetch_or_relaxed
374 #define atomic64_fetch_xor_relaxed atomic64_fetch_xor_relaxed
375
376 #undef ATOMIC64_OPS
377 #undef ATOMIC64_FETCH_OP
378 #undef ATOMIC64_OP_RETURN
379 #undef ATOMIC64_OP
380
381 /*
382 * atomic64_sub_if_positive - conditionally subtract integer from atomic
383 * variable
384 * @i: integer value to subtract
385 * @v: pointer of type atomic64_t
386 *
387 * Atomically test @v and subtract @i if @v is greater or equal than @i.
388 * The function returns the old value of @v minus @i.
389 */
390 static __inline__ s64 atomic64_sub_if_positive(s64 i, atomic64_t * v)
391 {
392 s64 result;
393
394 smp_mb__before_llsc();
395
396 if (kernel_uses_llsc) {
397 s64 temp;
398
399 __asm__ __volatile__(
400 " .set push \n"
401 " .set "MIPS_ISA_LEVEL" \n"
402 "1: lld %1, %2 # atomic64_sub_if_positive\n"
403 " dsubu %0, %1, %3 \n"
404 " move %1, %0 \n"
405 " bltz %0, 1f \n"
406 " scd %1, %2 \n"
407 "\t" __scbeqz " %1, 1b \n"
408 "1: \n"
409 " .set pop \n"
410 : "=&r" (result), "=&r" (temp),
411 "+" GCC_OFF_SMALL_ASM() (v->counter)
412 : "Ir" (i));
413 } else {
414 unsigned long flags;
415
416 raw_local_irq_save(flags);
417 result = v->counter;
418 result -= i;
419 if (result >= 0)
420 v->counter = result;
421 raw_local_irq_restore(flags);
422 }
423
424 smp_llsc_mb();
425
426 return result;
427 }
428
429 #define atomic64_cmpxchg(v, o, n) \
430 ((__typeof__((v)->counter))cmpxchg(&((v)->counter), (o), (n)))
431 #define atomic64_xchg(v, new) (xchg(&((v)->counter), (new)))
432
433 /*
434 * atomic64_dec_if_positive - decrement by 1 if old value positive
435 * @v: pointer of type atomic64_t
436 */
437 #define atomic64_dec_if_positive(v) atomic64_sub_if_positive(1, v)
438
439 #endif /* CONFIG_64BIT */
440
441 #endif /* _ASM_ATOMIC_H */