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/export.h>
23
24 /*
25 * If lockdep is enabled then we use the non-preemption spin-ops
26 * even on CONFIG_PREEMPT, because lockdep assumes that interrupts are
27 * not re-enabled during lock-acquire (which the preempt-spin-ops do):
28 */
29 #if !defined(CONFIG_GENERIC_LOCKBREAK) || defined(CONFIG_DEBUG_LOCK_ALLOC)
30 /*
31 * The __lock_function inlines are taken from
32 * include/linux/spinlock_api_smp.h
33 */
34 #else
35 #define raw_read_can_lock(l) read_can_lock(l)
36 #define raw_write_can_lock(l) write_can_lock(l)
37 /*
38 * We build the __lock_function inlines here. They are too large for
39 * inlining all over the place, but here is only one user per function
40 * which embedds them into the calling _lock_function below.
41 *
42 * This could be a long-held lock. We both prepare to spin for a long
43 * time (making _this_ CPU preemptable if possible), and we also signal
44 * towards that other CPU that it should break the lock ASAP.
45 */
46 #define BUILD_LOCK_OPS(op, locktype) \
47 void __lockfunc __raw_##op##_lock(locktype##_t *lock) \
48 { \
49 for (;;) { \
50 preempt_disable(); \
51 if (likely(do_raw_##op##_trylock(lock))) \
52 break; \
53 preempt_enable(); \
54 \
55 if (!(lock)->break_lock) \
56 (lock)->break_lock = 1; \
57 while (!raw_##op##_can_lock(lock) && (lock)->break_lock)\
58 arch_##op##_relax(&lock->raw_lock); \
59 } \
60 (lock)->break_lock = 0; \
61 } \
62 \
63 unsigned long __lockfunc __raw_##op##_lock_irqsave(locktype##_t *lock) \
64 { \
65 unsigned long flags; \
66 \
67 for (;;) { \
68 preempt_disable(); \
69 local_irq_save(flags); \
70 if (likely(do_raw_##op##_trylock(lock))) \
71 break; \
72 local_irq_restore(flags); \
73 preempt_enable(); \
74 \
75 if (!(lock)->break_lock) \
76 (lock)->break_lock = 1; \
77 while (!raw_##op##_can_lock(lock) && (lock)->break_lock)\
78 arch_##op##_relax(&lock->raw_lock); \
79 } \
80 (lock)->break_lock = 0; \
81 return flags; \
82 } \
83 \
84 void __lockfunc __raw_##op##_lock_irq(locktype##_t *lock) \
85 { \
86 _raw_##op##_lock_irqsave(lock); \
87 } \
88 \
89 void __lockfunc __raw_##op##_lock_bh(locktype##_t *lock) \
90 { \
91 unsigned long flags; \
92 \
93 /* */ \
94 /* Careful: we must exclude softirqs too, hence the */ \
95 /* irq-disabling. We use the generic preemption-aware */ \
96 /* function: */ \
97 /**/ \
98 flags = _raw_##op##_lock_irqsave(lock); \
99 local_bh_disable(); \
100 local_irq_restore(flags); \
101 } \
102
103 /*
104 * Build preemption-friendly versions of the following
105 * lock-spinning functions:
106 *
107 * __[spin|read|write]_lock()
108 * __[spin|read|write]_lock_irq()
109 * __[spin|read|write]_lock_irqsave()
110 * __[spin|read|write]_lock_bh()
111 */
112 BUILD_LOCK_OPS(spin, raw_spinlock);
113 BUILD_LOCK_OPS(read, rwlock);
114 BUILD_LOCK_OPS(write, rwlock);
115
116 #endif
117
118 #ifndef CONFIG_INLINE_SPIN_TRYLOCK
_raw_spin_trylock(raw_spinlock_t * lock)119 int __lockfunc _raw_spin_trylock(raw_spinlock_t *lock)
120 {
121 return __raw_spin_trylock(lock);
122 }
123 EXPORT_SYMBOL(_raw_spin_trylock);
124 #endif
125
126 #ifndef CONFIG_INLINE_SPIN_TRYLOCK_BH
_raw_spin_trylock_bh(raw_spinlock_t * lock)127 int __lockfunc _raw_spin_trylock_bh(raw_spinlock_t *lock)
128 {
129 return __raw_spin_trylock_bh(lock);
130 }
131 EXPORT_SYMBOL(_raw_spin_trylock_bh);
132 #endif
133
134 #ifndef CONFIG_INLINE_SPIN_LOCK
_raw_spin_lock(raw_spinlock_t * lock)135 void __lockfunc _raw_spin_lock(raw_spinlock_t *lock)
136 {
137 __raw_spin_lock(lock);
138 }
139 EXPORT_SYMBOL(_raw_spin_lock);
140 #endif
141
142 #ifndef CONFIG_INLINE_SPIN_LOCK_IRQSAVE
_raw_spin_lock_irqsave(raw_spinlock_t * lock)143 unsigned long __lockfunc _raw_spin_lock_irqsave(raw_spinlock_t *lock)
144 {
145 return __raw_spin_lock_irqsave(lock);
146 }
147 EXPORT_SYMBOL(_raw_spin_lock_irqsave);
148 #endif
149
150 #ifndef CONFIG_INLINE_SPIN_LOCK_IRQ
_raw_spin_lock_irq(raw_spinlock_t * lock)151 void __lockfunc _raw_spin_lock_irq(raw_spinlock_t *lock)
152 {
153 __raw_spin_lock_irq(lock);
154 }
155 EXPORT_SYMBOL(_raw_spin_lock_irq);
156 #endif
157
158 #ifndef CONFIG_INLINE_SPIN_LOCK_BH
_raw_spin_lock_bh(raw_spinlock_t * lock)159 void __lockfunc _raw_spin_lock_bh(raw_spinlock_t *lock)
160 {
161 __raw_spin_lock_bh(lock);
162 }
163 EXPORT_SYMBOL(_raw_spin_lock_bh);
164 #endif
165
166 #ifdef CONFIG_UNINLINE_SPIN_UNLOCK
_raw_spin_unlock(raw_spinlock_t * lock)167 void __lockfunc _raw_spin_unlock(raw_spinlock_t *lock)
168 {
169 __raw_spin_unlock(lock);
170 }
171 EXPORT_SYMBOL(_raw_spin_unlock);
172 #endif
173
174 #ifndef CONFIG_INLINE_SPIN_UNLOCK_IRQRESTORE
_raw_spin_unlock_irqrestore(raw_spinlock_t * lock,unsigned long flags)175 void __lockfunc _raw_spin_unlock_irqrestore(raw_spinlock_t *lock, unsigned long flags)
176 {
177 __raw_spin_unlock_irqrestore(lock, flags);
178 }
179 EXPORT_SYMBOL(_raw_spin_unlock_irqrestore);
180 #endif
181
182 #ifndef CONFIG_INLINE_SPIN_UNLOCK_IRQ
_raw_spin_unlock_irq(raw_spinlock_t * lock)183 void __lockfunc _raw_spin_unlock_irq(raw_spinlock_t *lock)
184 {
185 __raw_spin_unlock_irq(lock);
186 }
187 EXPORT_SYMBOL(_raw_spin_unlock_irq);
188 #endif
189
190 #ifndef CONFIG_INLINE_SPIN_UNLOCK_BH
_raw_spin_unlock_bh(raw_spinlock_t * lock)191 void __lockfunc _raw_spin_unlock_bh(raw_spinlock_t *lock)
192 {
193 __raw_spin_unlock_bh(lock);
194 }
195 EXPORT_SYMBOL(_raw_spin_unlock_bh);
196 #endif
197
198 #ifndef CONFIG_INLINE_READ_TRYLOCK
_raw_read_trylock(rwlock_t * lock)199 int __lockfunc _raw_read_trylock(rwlock_t *lock)
200 {
201 return __raw_read_trylock(lock);
202 }
203 EXPORT_SYMBOL(_raw_read_trylock);
204 #endif
205
206 #ifndef CONFIG_INLINE_READ_LOCK
_raw_read_lock(rwlock_t * lock)207 void __lockfunc _raw_read_lock(rwlock_t *lock)
208 {
209 __raw_read_lock(lock);
210 }
211 EXPORT_SYMBOL(_raw_read_lock);
212 #endif
213
214 #ifndef CONFIG_INLINE_READ_LOCK_IRQSAVE
_raw_read_lock_irqsave(rwlock_t * lock)215 unsigned long __lockfunc _raw_read_lock_irqsave(rwlock_t *lock)
216 {
217 return __raw_read_lock_irqsave(lock);
218 }
219 EXPORT_SYMBOL(_raw_read_lock_irqsave);
220 #endif
221
222 #ifndef CONFIG_INLINE_READ_LOCK_IRQ
_raw_read_lock_irq(rwlock_t * lock)223 void __lockfunc _raw_read_lock_irq(rwlock_t *lock)
224 {
225 __raw_read_lock_irq(lock);
226 }
227 EXPORT_SYMBOL(_raw_read_lock_irq);
228 #endif
229
230 #ifndef CONFIG_INLINE_READ_LOCK_BH
_raw_read_lock_bh(rwlock_t * lock)231 void __lockfunc _raw_read_lock_bh(rwlock_t *lock)
232 {
233 __raw_read_lock_bh(lock);
234 }
235 EXPORT_SYMBOL(_raw_read_lock_bh);
236 #endif
237
238 #ifndef CONFIG_INLINE_READ_UNLOCK
_raw_read_unlock(rwlock_t * lock)239 void __lockfunc _raw_read_unlock(rwlock_t *lock)
240 {
241 __raw_read_unlock(lock);
242 }
243 EXPORT_SYMBOL(_raw_read_unlock);
244 #endif
245
246 #ifndef CONFIG_INLINE_READ_UNLOCK_IRQRESTORE
_raw_read_unlock_irqrestore(rwlock_t * lock,unsigned long flags)247 void __lockfunc _raw_read_unlock_irqrestore(rwlock_t *lock, unsigned long flags)
248 {
249 __raw_read_unlock_irqrestore(lock, flags);
250 }
251 EXPORT_SYMBOL(_raw_read_unlock_irqrestore);
252 #endif
253
254 #ifndef CONFIG_INLINE_READ_UNLOCK_IRQ
_raw_read_unlock_irq(rwlock_t * lock)255 void __lockfunc _raw_read_unlock_irq(rwlock_t *lock)
256 {
257 __raw_read_unlock_irq(lock);
258 }
259 EXPORT_SYMBOL(_raw_read_unlock_irq);
260 #endif
261
262 #ifndef CONFIG_INLINE_READ_UNLOCK_BH
_raw_read_unlock_bh(rwlock_t * lock)263 void __lockfunc _raw_read_unlock_bh(rwlock_t *lock)
264 {
265 __raw_read_unlock_bh(lock);
266 }
267 EXPORT_SYMBOL(_raw_read_unlock_bh);
268 #endif
269
270 #ifndef CONFIG_INLINE_WRITE_TRYLOCK
_raw_write_trylock(rwlock_t * lock)271 int __lockfunc _raw_write_trylock(rwlock_t *lock)
272 {
273 return __raw_write_trylock(lock);
274 }
275 EXPORT_SYMBOL(_raw_write_trylock);
276 #endif
277
278 #ifndef CONFIG_INLINE_WRITE_LOCK
_raw_write_lock(rwlock_t * lock)279 void __lockfunc _raw_write_lock(rwlock_t *lock)
280 {
281 __raw_write_lock(lock);
282 }
283 EXPORT_SYMBOL(_raw_write_lock);
284 #endif
285
286 #ifndef CONFIG_INLINE_WRITE_LOCK_IRQSAVE
_raw_write_lock_irqsave(rwlock_t * lock)287 unsigned long __lockfunc _raw_write_lock_irqsave(rwlock_t *lock)
288 {
289 return __raw_write_lock_irqsave(lock);
290 }
291 EXPORT_SYMBOL(_raw_write_lock_irqsave);
292 #endif
293
294 #ifndef CONFIG_INLINE_WRITE_LOCK_IRQ
_raw_write_lock_irq(rwlock_t * lock)295 void __lockfunc _raw_write_lock_irq(rwlock_t *lock)
296 {
297 __raw_write_lock_irq(lock);
298 }
299 EXPORT_SYMBOL(_raw_write_lock_irq);
300 #endif
301
302 #ifndef CONFIG_INLINE_WRITE_LOCK_BH
_raw_write_lock_bh(rwlock_t * lock)303 void __lockfunc _raw_write_lock_bh(rwlock_t *lock)
304 {
305 __raw_write_lock_bh(lock);
306 }
307 EXPORT_SYMBOL(_raw_write_lock_bh);
308 #endif
309
310 #ifndef CONFIG_INLINE_WRITE_UNLOCK
_raw_write_unlock(rwlock_t * lock)311 void __lockfunc _raw_write_unlock(rwlock_t *lock)
312 {
313 __raw_write_unlock(lock);
314 }
315 EXPORT_SYMBOL(_raw_write_unlock);
316 #endif
317
318 #ifndef CONFIG_INLINE_WRITE_UNLOCK_IRQRESTORE
_raw_write_unlock_irqrestore(rwlock_t * lock,unsigned long flags)319 void __lockfunc _raw_write_unlock_irqrestore(rwlock_t *lock, unsigned long flags)
320 {
321 __raw_write_unlock_irqrestore(lock, flags);
322 }
323 EXPORT_SYMBOL(_raw_write_unlock_irqrestore);
324 #endif
325
326 #ifndef CONFIG_INLINE_WRITE_UNLOCK_IRQ
_raw_write_unlock_irq(rwlock_t * lock)327 void __lockfunc _raw_write_unlock_irq(rwlock_t *lock)
328 {
329 __raw_write_unlock_irq(lock);
330 }
331 EXPORT_SYMBOL(_raw_write_unlock_irq);
332 #endif
333
334 #ifndef CONFIG_INLINE_WRITE_UNLOCK_BH
_raw_write_unlock_bh(rwlock_t * lock)335 void __lockfunc _raw_write_unlock_bh(rwlock_t *lock)
336 {
337 __raw_write_unlock_bh(lock);
338 }
339 EXPORT_SYMBOL(_raw_write_unlock_bh);
340 #endif
341
342 #ifdef CONFIG_DEBUG_LOCK_ALLOC
343
_raw_spin_lock_nested(raw_spinlock_t * lock,int subclass)344 void __lockfunc _raw_spin_lock_nested(raw_spinlock_t *lock, int subclass)
345 {
346 preempt_disable();
347 spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
348 LOCK_CONTENDED(lock, do_raw_spin_trylock, do_raw_spin_lock);
349 }
350 EXPORT_SYMBOL(_raw_spin_lock_nested);
351
_raw_spin_lock_irqsave_nested(raw_spinlock_t * lock,int subclass)352 unsigned long __lockfunc _raw_spin_lock_irqsave_nested(raw_spinlock_t *lock,
353 int subclass)
354 {
355 unsigned long flags;
356
357 local_irq_save(flags);
358 preempt_disable();
359 spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
360 LOCK_CONTENDED_FLAGS(lock, do_raw_spin_trylock, do_raw_spin_lock,
361 do_raw_spin_lock_flags, &flags);
362 return flags;
363 }
364 EXPORT_SYMBOL(_raw_spin_lock_irqsave_nested);
365
_raw_spin_lock_nest_lock(raw_spinlock_t * lock,struct lockdep_map * nest_lock)366 void __lockfunc _raw_spin_lock_nest_lock(raw_spinlock_t *lock,
367 struct lockdep_map *nest_lock)
368 {
369 preempt_disable();
370 spin_acquire_nest(&lock->dep_map, 0, 0, nest_lock, _RET_IP_);
371 LOCK_CONTENDED(lock, do_raw_spin_trylock, do_raw_spin_lock);
372 }
373 EXPORT_SYMBOL(_raw_spin_lock_nest_lock);
374
375 #endif
376
in_lock_functions(unsigned long addr)377 notrace int in_lock_functions(unsigned long addr)
378 {
379 /* Linker adds these: start and end of __lockfunc functions */
380 extern char __lock_text_start[], __lock_text_end[];
381
382 return addr >= (unsigned long)__lock_text_start
383 && addr < (unsigned long)__lock_text_end;
384 }
385 EXPORT_SYMBOL(in_lock_functions);
386