1 /*
2 * Copyright (2004) Linus Torvalds
3 *
4 * Author: Zwane Mwaikambo <zwane@fsmlabs.com>
5 *
6 * Copyright (2004, 2005) Ingo Molnar
7 *
8 * This file contains the spinlock/rwlock implementations for the
9 * SMP and the DEBUG_SPINLOCK cases. (UP-nondebug inlines them)
10 *
11 * Note that some architectures have special knowledge about the
12 * stack frames of these functions in their profile_pc. If you
13 * change anything significant here that could change the stack
14 * frame contact the architecture maintainers.
15 */
16
17 #include <linux/linkage.h>
18 #include <linux/preempt.h>
19 #include <linux/spinlock.h>
20 #include <linux/interrupt.h>
21 #include <linux/debug_locks.h>
22 #include <linux/module.h>
23
24 int __lockfunc _spin_trylock(spinlock_t *lock)
25 {
26 preempt_disable();
27 if (_raw_spin_trylock(lock)) {
28 spin_acquire(&lock->dep_map, 0, 1, _RET_IP_);
29 return 1;
30 }
31
32 preempt_enable();
33 return 0;
34 }
35 EXPORT_SYMBOL(_spin_trylock);
36
37 int __lockfunc _read_trylock(rwlock_t *lock)
38 {
39 preempt_disable();
40 if (_raw_read_trylock(lock)) {
41 rwlock_acquire_read(&lock->dep_map, 0, 1, _RET_IP_);
42 return 1;
43 }
44
45 preempt_enable();
46 return 0;
47 }
48 EXPORT_SYMBOL(_read_trylock);
49
50 int __lockfunc _write_trylock(rwlock_t *lock)
51 {
52 preempt_disable();
53 if (_raw_write_trylock(lock)) {
54 rwlock_acquire(&lock->dep_map, 0, 1, _RET_IP_);
55 return 1;
56 }
57
58 preempt_enable();
59 return 0;
60 }
61 EXPORT_SYMBOL(_write_trylock);
62
63 /*
64 * If lockdep is enabled then we use the non-preemption spin-ops
65 * even on CONFIG_PREEMPT, because lockdep assumes that interrupts are
66 * not re-enabled during lock-acquire (which the preempt-spin-ops do):
67 */
68 #if !defined(CONFIG_GENERIC_LOCKBREAK) || defined(CONFIG_DEBUG_LOCK_ALLOC)
69
70 void __lockfunc _read_lock(rwlock_t *lock)
71 {
72 preempt_disable();
73 rwlock_acquire_read(&lock->dep_map, 0, 0, _RET_IP_);
74 LOCK_CONTENDED(lock, _raw_read_trylock, _raw_read_lock);
75 }
76 EXPORT_SYMBOL(_read_lock);
77
78 unsigned long __lockfunc _spin_lock_irqsave(spinlock_t *lock)
79 {
80 unsigned long flags;
81
82 local_irq_save(flags);
83 preempt_disable();
84 spin_acquire(&lock->dep_map, 0, 0, _RET_IP_);
85 /*
86 * On lockdep we dont want the hand-coded irq-enable of
87 * _raw_spin_lock_flags() code, because lockdep assumes
88 * that interrupts are not re-enabled during lock-acquire:
89 */
90 #ifdef CONFIG_LOCKDEP
91 LOCK_CONTENDED(lock, _raw_spin_trylock, _raw_spin_lock);
92 #else
93 _raw_spin_lock_flags(lock, &flags);
94 #endif
95 return flags;
96 }
97 EXPORT_SYMBOL(_spin_lock_irqsave);
98
99 void __lockfunc _spin_lock_irq(spinlock_t *lock)
100 {
101 local_irq_disable();
102 preempt_disable();
103 spin_acquire(&lock->dep_map, 0, 0, _RET_IP_);
104 LOCK_CONTENDED(lock, _raw_spin_trylock, _raw_spin_lock);
105 }
106 EXPORT_SYMBOL(_spin_lock_irq);
107
108 void __lockfunc _spin_lock_bh(spinlock_t *lock)
109 {
110 local_bh_disable();
111 preempt_disable();
112 spin_acquire(&lock->dep_map, 0, 0, _RET_IP_);
113 LOCK_CONTENDED(lock, _raw_spin_trylock, _raw_spin_lock);
114 }
115 EXPORT_SYMBOL(_spin_lock_bh);
116
117 unsigned long __lockfunc _read_lock_irqsave(rwlock_t *lock)
118 {
119 unsigned long flags;
120
121 local_irq_save(flags);
122 preempt_disable();
123 rwlock_acquire_read(&lock->dep_map, 0, 0, _RET_IP_);
124 LOCK_CONTENDED_FLAGS(lock, _raw_read_trylock, _raw_read_lock,
125 _raw_read_lock_flags, &flags);
126 return flags;
127 }
128 EXPORT_SYMBOL(_read_lock_irqsave);
129
130 void __lockfunc _read_lock_irq(rwlock_t *lock)
131 {
132 local_irq_disable();
133 preempt_disable();
134 rwlock_acquire_read(&lock->dep_map, 0, 0, _RET_IP_);
135 LOCK_CONTENDED(lock, _raw_read_trylock, _raw_read_lock);
136 }
137 EXPORT_SYMBOL(_read_lock_irq);
138
139 void __lockfunc _read_lock_bh(rwlock_t *lock)
140 {
141 local_bh_disable();
142 preempt_disable();
143 rwlock_acquire_read(&lock->dep_map, 0, 0, _RET_IP_);
144 LOCK_CONTENDED(lock, _raw_read_trylock, _raw_read_lock);
145 }
146 EXPORT_SYMBOL(_read_lock_bh);
147
148 unsigned long __lockfunc _write_lock_irqsave(rwlock_t *lock)
149 {
150 unsigned long flags;
151
152 local_irq_save(flags);
153 preempt_disable();
154 rwlock_acquire(&lock->dep_map, 0, 0, _RET_IP_);
155 LOCK_CONTENDED_FLAGS(lock, _raw_write_trylock, _raw_write_lock,
156 _raw_write_lock_flags, &flags);
157 return flags;
158 }
159 EXPORT_SYMBOL(_write_lock_irqsave);
160
161 void __lockfunc _write_lock_irq(rwlock_t *lock)
162 {
163 local_irq_disable();
164 preempt_disable();
165 rwlock_acquire(&lock->dep_map, 0, 0, _RET_IP_);
166 LOCK_CONTENDED(lock, _raw_write_trylock, _raw_write_lock);
167 }
168 EXPORT_SYMBOL(_write_lock_irq);
169
170 void __lockfunc _write_lock_bh(rwlock_t *lock)
171 {
172 local_bh_disable();
173 preempt_disable();
174 rwlock_acquire(&lock->dep_map, 0, 0, _RET_IP_);
175 LOCK_CONTENDED(lock, _raw_write_trylock, _raw_write_lock);
176 }
177 EXPORT_SYMBOL(_write_lock_bh);
178
179 void __lockfunc _spin_lock(spinlock_t *lock)
180 {
181 preempt_disable();
182 spin_acquire(&lock->dep_map, 0, 0, _RET_IP_);
183 LOCK_CONTENDED(lock, _raw_spin_trylock, _raw_spin_lock);
184 }
185
186 EXPORT_SYMBOL(_spin_lock);
187
188 void __lockfunc _write_lock(rwlock_t *lock)
189 {
190 preempt_disable();
191 rwlock_acquire(&lock->dep_map, 0, 0, _RET_IP_);
192 LOCK_CONTENDED(lock, _raw_write_trylock, _raw_write_lock);
193 }
194
195 EXPORT_SYMBOL(_write_lock);
196
197 #else /* CONFIG_PREEMPT: */
198
199 /*
200 * This could be a long-held lock. We both prepare to spin for a long
201 * time (making _this_ CPU preemptable if possible), and we also signal
202 * towards that other CPU that it should break the lock ASAP.
203 *
204 * (We do this in a function because inlining it would be excessive.)
205 */
206
207 #define BUILD_LOCK_OPS(op, locktype) \
208 void __lockfunc _##op##_lock(locktype##_t *lock) \
209 { \
210 for (;;) { \
211 preempt_disable(); \
212 if (likely(_raw_##op##_trylock(lock))) \
213 break; \
214 preempt_enable(); \
215 \
216 if (!(lock)->break_lock) \
217 (lock)->break_lock = 1; \
218 while (!op##_can_lock(lock) && (lock)->break_lock) \
219 _raw_##op##_relax(&lock->raw_lock); \
220 } \
221 (lock)->break_lock = 0; \
222 } \
223 \
224 EXPORT_SYMBOL(_##op##_lock); \
225 \
226 unsigned long __lockfunc _##op##_lock_irqsave(locktype##_t *lock) \
227 { \
228 unsigned long flags; \
229 \
230 for (;;) { \
231 preempt_disable(); \
232 local_irq_save(flags); \
233 if (likely(_raw_##op##_trylock(lock))) \
234 break; \
235 local_irq_restore(flags); \
236 preempt_enable(); \
237 \
238 if (!(lock)->break_lock) \
239 (lock)->break_lock = 1; \
240 while (!op##_can_lock(lock) && (lock)->break_lock) \
241 _raw_##op##_relax(&lock->raw_lock); \
242 } \
243 (lock)->break_lock = 0; \
244 return flags; \
245 } \
246 \
247 EXPORT_SYMBOL(_##op##_lock_irqsave); \
248 \
249 void __lockfunc _##op##_lock_irq(locktype##_t *lock) \
250 { \
251 _##op##_lock_irqsave(lock); \
252 } \
253 \
254 EXPORT_SYMBOL(_##op##_lock_irq); \
255 \
256 void __lockfunc _##op##_lock_bh(locktype##_t *lock) \
257 { \
258 unsigned long flags; \
259 \
260 /* */ \
261 /* Careful: we must exclude softirqs too, hence the */ \
262 /* irq-disabling. We use the generic preemption-aware */ \
263 /* function: */ \
264 /**/ \
265 flags = _##op##_lock_irqsave(lock); \
266 local_bh_disable(); \
267 local_irq_restore(flags); \
268 } \
269 \
270 EXPORT_SYMBOL(_##op##_lock_bh)
271
272 /*
273 * Build preemption-friendly versions of the following
274 * lock-spinning functions:
275 *
276 * _[spin|read|write]_lock()
277 * _[spin|read|write]_lock_irq()
278 * _[spin|read|write]_lock_irqsave()
279 * _[spin|read|write]_lock_bh()
280 */
281 BUILD_LOCK_OPS(spin, spinlock);
282 BUILD_LOCK_OPS(read, rwlock);
283 BUILD_LOCK_OPS(write, rwlock);
284
285 #endif /* CONFIG_PREEMPT */
286
287 #ifdef CONFIG_DEBUG_LOCK_ALLOC
288
289 void __lockfunc _spin_lock_nested(spinlock_t *lock, int subclass)
290 {
291 preempt_disable();
292 spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
293 LOCK_CONTENDED(lock, _raw_spin_trylock, _raw_spin_lock);
294 }
295 EXPORT_SYMBOL(_spin_lock_nested);
296
297 unsigned long __lockfunc _spin_lock_irqsave_nested(spinlock_t *lock, int subclass)
298 {
299 unsigned long flags;
300
301 local_irq_save(flags);
302 preempt_disable();
303 spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
304 LOCK_CONTENDED_FLAGS(lock, _raw_spin_trylock, _raw_spin_lock,
305 _raw_spin_lock_flags, &flags);
306 return flags;
307 }
308 EXPORT_SYMBOL(_spin_lock_irqsave_nested);
309
310 void __lockfunc _spin_lock_nest_lock(spinlock_t *lock,
311 struct lockdep_map *nest_lock)
312 {
313 preempt_disable();
314 spin_acquire_nest(&lock->dep_map, 0, 0, nest_lock, _RET_IP_);
315 LOCK_CONTENDED(lock, _raw_spin_trylock, _raw_spin_lock);
316 }
317 EXPORT_SYMBOL(_spin_lock_nest_lock);
318
319 #endif
320
321 void __lockfunc _spin_unlock(spinlock_t *lock)
322 {
323 spin_release(&lock->dep_map, 1, _RET_IP_);
324 _raw_spin_unlock(lock);
325 preempt_enable();
326 }
327 EXPORT_SYMBOL(_spin_unlock);
328
329 void __lockfunc _write_unlock(rwlock_t *lock)
330 {
331 rwlock_release(&lock->dep_map, 1, _RET_IP_);
332 _raw_write_unlock(lock);
333 preempt_enable();
334 }
335 EXPORT_SYMBOL(_write_unlock);
336
337 void __lockfunc _read_unlock(rwlock_t *lock)
338 {
339 rwlock_release(&lock->dep_map, 1, _RET_IP_);
340 _raw_read_unlock(lock);
341 preempt_enable();
342 }
343 EXPORT_SYMBOL(_read_unlock);
344
345 void __lockfunc _spin_unlock_irqrestore(spinlock_t *lock, unsigned long flags)
346 {
347 spin_release(&lock->dep_map, 1, _RET_IP_);
348 _raw_spin_unlock(lock);
349 local_irq_restore(flags);
350 preempt_enable();
351 }
352 EXPORT_SYMBOL(_spin_unlock_irqrestore);
353
354 void __lockfunc _spin_unlock_irq(spinlock_t *lock)
355 {
356 spin_release(&lock->dep_map, 1, _RET_IP_);
357 _raw_spin_unlock(lock);
358 local_irq_enable();
359 preempt_enable();
360 }
361 EXPORT_SYMBOL(_spin_unlock_irq);
362
363 void __lockfunc _spin_unlock_bh(spinlock_t *lock)
364 {
365 spin_release(&lock->dep_map, 1, _RET_IP_);
366 _raw_spin_unlock(lock);
367 preempt_enable_no_resched();
368 local_bh_enable_ip((unsigned long)__builtin_return_address(0));
369 }
370 EXPORT_SYMBOL(_spin_unlock_bh);
371
372 void __lockfunc _read_unlock_irqrestore(rwlock_t *lock, unsigned long flags)
373 {
374 rwlock_release(&lock->dep_map, 1, _RET_IP_);
375 _raw_read_unlock(lock);
376 local_irq_restore(flags);
377 preempt_enable();
378 }
379 EXPORT_SYMBOL(_read_unlock_irqrestore);
380
381 void __lockfunc _read_unlock_irq(rwlock_t *lock)
382 {
383 rwlock_release(&lock->dep_map, 1, _RET_IP_);
384 _raw_read_unlock(lock);
385 local_irq_enable();
386 preempt_enable();
387 }
388 EXPORT_SYMBOL(_read_unlock_irq);
389
390 void __lockfunc _read_unlock_bh(rwlock_t *lock)
391 {
392 rwlock_release(&lock->dep_map, 1, _RET_IP_);
393 _raw_read_unlock(lock);
394 preempt_enable_no_resched();
395 local_bh_enable_ip((unsigned long)__builtin_return_address(0));
396 }
397 EXPORT_SYMBOL(_read_unlock_bh);
398
399 void __lockfunc _write_unlock_irqrestore(rwlock_t *lock, unsigned long flags)
400 {
401 rwlock_release(&lock->dep_map, 1, _RET_IP_);
402 _raw_write_unlock(lock);
403 local_irq_restore(flags);
404 preempt_enable();
405 }
406 EXPORT_SYMBOL(_write_unlock_irqrestore);
407
408 void __lockfunc _write_unlock_irq(rwlock_t *lock)
409 {
410 rwlock_release(&lock->dep_map, 1, _RET_IP_);
411 _raw_write_unlock(lock);
412 local_irq_enable();
413 preempt_enable();
414 }
415 EXPORT_SYMBOL(_write_unlock_irq);
416
417 void __lockfunc _write_unlock_bh(rwlock_t *lock)
418 {
419 rwlock_release(&lock->dep_map, 1, _RET_IP_);
420 _raw_write_unlock(lock);
421 preempt_enable_no_resched();
422 local_bh_enable_ip((unsigned long)__builtin_return_address(0));
423 }
424 EXPORT_SYMBOL(_write_unlock_bh);
425
426 int __lockfunc _spin_trylock_bh(spinlock_t *lock)
427 {
428 local_bh_disable();
429 preempt_disable();
430 if (_raw_spin_trylock(lock)) {
431 spin_acquire(&lock->dep_map, 0, 1, _RET_IP_);
432 return 1;
433 }
434
435 preempt_enable_no_resched();
436 local_bh_enable_ip((unsigned long)__builtin_return_address(0));
437 return 0;
438 }
439 EXPORT_SYMBOL(_spin_trylock_bh);
440
441 notrace int in_lock_functions(unsigned long addr)
442 {
443 /* Linker adds these: start and end of __lockfunc functions */
444 extern char __lock_text_start[], __lock_text_end[];
445
446 return addr >= (unsigned long)__lock_text_start
447 && addr < (unsigned long)__lock_text_end;
448 }
449 EXPORT_SYMBOL(in_lock_functions);
450
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