1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (2004) Linus Torvalds
4 *
5 * Author: Zwane Mwaikambo <zwane@fsmlabs.com>
6 *
7 * Copyright (2004, 2005) Ingo Molnar
8 *
9 * This file contains the spinlock/rwlock implementations for the
10 * SMP and the DEBUG_SPINLOCK cases. (UP-nondebug inlines them)
11 *
12 * Note that some architectures have special knowledge about the
13 * stack frames of these functions in their profile_pc. If you
14 * change anything significant here that could change the stack
15 * frame contact the architecture maintainers.
16 */
17
18 #include <linux/linkage.h>
19 #include <linux/preempt.h>
20 #include <linux/spinlock.h>
21 #include <linux/interrupt.h>
22 #include <linux/debug_locks.h>
23 #include <linux/export.h>
24
25 #ifdef CONFIG_MMIOWB
26 #ifndef arch_mmiowb_state
27 DEFINE_PER_CPU(struct mmiowb_state, __mmiowb_state);
28 EXPORT_PER_CPU_SYMBOL(__mmiowb_state);
29 #endif
30 #endif
31
32 /*
33 * If lockdep is enabled then we use the non-preemption spin-ops
34 * even on CONFIG_PREEMPT, because lockdep assumes that interrupts are
35 * not re-enabled during lock-acquire (which the preempt-spin-ops do):
36 */
37 #if !defined(CONFIG_GENERIC_LOCKBREAK) || defined(CONFIG_DEBUG_LOCK_ALLOC)
38 /*
39 * The __lock_function inlines are taken from
40 * spinlock : include/linux/spinlock_api_smp.h
41 * rwlock : include/linux/rwlock_api_smp.h
42 */
43 #else
44
45 /*
46 * Some architectures can relax in favour of the CPU owning the lock.
47 */
48 #ifndef arch_read_relax
49 # define arch_read_relax(l) cpu_relax()
50 #endif
51 #ifndef arch_write_relax
52 # define arch_write_relax(l) cpu_relax()
53 #endif
54 #ifndef arch_spin_relax
55 # define arch_spin_relax(l) cpu_relax()
56 #endif
57
58 /*
59 * We build the __lock_function inlines here. They are too large for
60 * inlining all over the place, but here is only one user per function
61 * which embedds them into the calling _lock_function below.
62 *
63 * This could be a long-held lock. We both prepare to spin for a long
64 * time (making _this_ CPU preemptable if possible), and we also signal
65 * towards that other CPU that it should break the lock ASAP.
66 */
67 #define BUILD_LOCK_OPS(op, locktype) \
68 void __lockfunc __raw_##op##_lock(locktype##_t *lock) \
69 { \
70 for (;;) { \
71 preempt_disable(); \
72 if (likely(do_raw_##op##_trylock(lock))) \
73 break; \
74 preempt_enable(); \
75 \
76 arch_##op##_relax(&lock->raw_lock); \
77 } \
78 } \
79 \
80 unsigned long __lockfunc __raw_##op##_lock_irqsave(locktype##_t *lock) \
81 { \
82 unsigned long flags; \
83 \
84 for (;;) { \
85 preempt_disable(); \
86 local_irq_save(flags); \
87 if (likely(do_raw_##op##_trylock(lock))) \
88 break; \
89 local_irq_restore(flags); \
90 preempt_enable(); \
91 \
92 arch_##op##_relax(&lock->raw_lock); \
93 } \
94 \
95 return flags; \
96 } \
97 \
98 void __lockfunc __raw_##op##_lock_irq(locktype##_t *lock) \
99 { \
100 _raw_##op##_lock_irqsave(lock); \
101 } \
102 \
103 void __lockfunc __raw_##op##_lock_bh(locktype##_t *lock) \
104 { \
105 unsigned long flags; \
106 \
107 /* */ \
108 /* Careful: we must exclude softirqs too, hence the */ \
109 /* irq-disabling. We use the generic preemption-aware */ \
110 /* function: */ \
111 /**/ \
112 flags = _raw_##op##_lock_irqsave(lock); \
113 local_bh_disable(); \
114 local_irq_restore(flags); \
115 } \
116
117 /*
118 * Build preemption-friendly versions of the following
119 * lock-spinning functions:
120 *
121 * __[spin|read|write]_lock()
122 * __[spin|read|write]_lock_irq()
123 * __[spin|read|write]_lock_irqsave()
124 * __[spin|read|write]_lock_bh()
125 */
126 BUILD_LOCK_OPS(spin, raw_spinlock);
127 BUILD_LOCK_OPS(read, rwlock);
128 BUILD_LOCK_OPS(write, rwlock);
129
130 #endif
131
132 #ifndef CONFIG_INLINE_SPIN_TRYLOCK
_raw_spin_trylock(raw_spinlock_t * lock)133 int __lockfunc _raw_spin_trylock(raw_spinlock_t *lock)
134 {
135 return __raw_spin_trylock(lock);
136 }
137 EXPORT_SYMBOL(_raw_spin_trylock);
138 #endif
139
140 #ifndef CONFIG_INLINE_SPIN_TRYLOCK_BH
_raw_spin_trylock_bh(raw_spinlock_t * lock)141 int __lockfunc _raw_spin_trylock_bh(raw_spinlock_t *lock)
142 {
143 return __raw_spin_trylock_bh(lock);
144 }
145 EXPORT_SYMBOL(_raw_spin_trylock_bh);
146 #endif
147
148 #ifndef CONFIG_INLINE_SPIN_LOCK
_raw_spin_lock(raw_spinlock_t * lock)149 void __lockfunc _raw_spin_lock(raw_spinlock_t *lock)
150 {
151 __raw_spin_lock(lock);
152 }
153 EXPORT_SYMBOL(_raw_spin_lock);
154 #endif
155
156 #ifndef CONFIG_INLINE_SPIN_LOCK_IRQSAVE
_raw_spin_lock_irqsave(raw_spinlock_t * lock)157 unsigned long __lockfunc _raw_spin_lock_irqsave(raw_spinlock_t *lock)
158 {
159 return __raw_spin_lock_irqsave(lock);
160 }
161 EXPORT_SYMBOL(_raw_spin_lock_irqsave);
162 #endif
163
164 #ifndef CONFIG_INLINE_SPIN_LOCK_IRQ
_raw_spin_lock_irq(raw_spinlock_t * lock)165 void __lockfunc _raw_spin_lock_irq(raw_spinlock_t *lock)
166 {
167 __raw_spin_lock_irq(lock);
168 }
169 EXPORT_SYMBOL(_raw_spin_lock_irq);
170 #endif
171
172 #ifndef CONFIG_INLINE_SPIN_LOCK_BH
_raw_spin_lock_bh(raw_spinlock_t * lock)173 void __lockfunc _raw_spin_lock_bh(raw_spinlock_t *lock)
174 {
175 __raw_spin_lock_bh(lock);
176 }
177 EXPORT_SYMBOL(_raw_spin_lock_bh);
178 #endif
179
180 #ifdef CONFIG_UNINLINE_SPIN_UNLOCK
_raw_spin_unlock(raw_spinlock_t * lock)181 void __lockfunc _raw_spin_unlock(raw_spinlock_t *lock)
182 {
183 __raw_spin_unlock(lock);
184 }
185 EXPORT_SYMBOL(_raw_spin_unlock);
186 #endif
187
188 #ifndef CONFIG_INLINE_SPIN_UNLOCK_IRQRESTORE
_raw_spin_unlock_irqrestore(raw_spinlock_t * lock,unsigned long flags)189 void __lockfunc _raw_spin_unlock_irqrestore(raw_spinlock_t *lock, unsigned long flags)
190 {
191 __raw_spin_unlock_irqrestore(lock, flags);
192 }
193 EXPORT_SYMBOL(_raw_spin_unlock_irqrestore);
194 #endif
195
196 #ifndef CONFIG_INLINE_SPIN_UNLOCK_IRQ
_raw_spin_unlock_irq(raw_spinlock_t * lock)197 void __lockfunc _raw_spin_unlock_irq(raw_spinlock_t *lock)
198 {
199 __raw_spin_unlock_irq(lock);
200 }
201 EXPORT_SYMBOL(_raw_spin_unlock_irq);
202 #endif
203
204 #ifndef CONFIG_INLINE_SPIN_UNLOCK_BH
_raw_spin_unlock_bh(raw_spinlock_t * lock)205 void __lockfunc _raw_spin_unlock_bh(raw_spinlock_t *lock)
206 {
207 __raw_spin_unlock_bh(lock);
208 }
209 EXPORT_SYMBOL(_raw_spin_unlock_bh);
210 #endif
211
212 #ifndef CONFIG_INLINE_READ_TRYLOCK
_raw_read_trylock(rwlock_t * lock)213 int __lockfunc _raw_read_trylock(rwlock_t *lock)
214 {
215 return __raw_read_trylock(lock);
216 }
217 EXPORT_SYMBOL(_raw_read_trylock);
218 #endif
219
220 #ifndef CONFIG_INLINE_READ_LOCK
_raw_read_lock(rwlock_t * lock)221 void __lockfunc _raw_read_lock(rwlock_t *lock)
222 {
223 __raw_read_lock(lock);
224 }
225 EXPORT_SYMBOL(_raw_read_lock);
226 #endif
227
228 #ifndef CONFIG_INLINE_READ_LOCK_IRQSAVE
_raw_read_lock_irqsave(rwlock_t * lock)229 unsigned long __lockfunc _raw_read_lock_irqsave(rwlock_t *lock)
230 {
231 return __raw_read_lock_irqsave(lock);
232 }
233 EXPORT_SYMBOL(_raw_read_lock_irqsave);
234 #endif
235
236 #ifndef CONFIG_INLINE_READ_LOCK_IRQ
_raw_read_lock_irq(rwlock_t * lock)237 void __lockfunc _raw_read_lock_irq(rwlock_t *lock)
238 {
239 __raw_read_lock_irq(lock);
240 }
241 EXPORT_SYMBOL(_raw_read_lock_irq);
242 #endif
243
244 #ifndef CONFIG_INLINE_READ_LOCK_BH
_raw_read_lock_bh(rwlock_t * lock)245 void __lockfunc _raw_read_lock_bh(rwlock_t *lock)
246 {
247 __raw_read_lock_bh(lock);
248 }
249 EXPORT_SYMBOL(_raw_read_lock_bh);
250 #endif
251
252 #ifndef CONFIG_INLINE_READ_UNLOCK
_raw_read_unlock(rwlock_t * lock)253 void __lockfunc _raw_read_unlock(rwlock_t *lock)
254 {
255 __raw_read_unlock(lock);
256 }
257 EXPORT_SYMBOL(_raw_read_unlock);
258 #endif
259
260 #ifndef CONFIG_INLINE_READ_UNLOCK_IRQRESTORE
_raw_read_unlock_irqrestore(rwlock_t * lock,unsigned long flags)261 void __lockfunc _raw_read_unlock_irqrestore(rwlock_t *lock, unsigned long flags)
262 {
263 __raw_read_unlock_irqrestore(lock, flags);
264 }
265 EXPORT_SYMBOL(_raw_read_unlock_irqrestore);
266 #endif
267
268 #ifndef CONFIG_INLINE_READ_UNLOCK_IRQ
_raw_read_unlock_irq(rwlock_t * lock)269 void __lockfunc _raw_read_unlock_irq(rwlock_t *lock)
270 {
271 __raw_read_unlock_irq(lock);
272 }
273 EXPORT_SYMBOL(_raw_read_unlock_irq);
274 #endif
275
276 #ifndef CONFIG_INLINE_READ_UNLOCK_BH
_raw_read_unlock_bh(rwlock_t * lock)277 void __lockfunc _raw_read_unlock_bh(rwlock_t *lock)
278 {
279 __raw_read_unlock_bh(lock);
280 }
281 EXPORT_SYMBOL(_raw_read_unlock_bh);
282 #endif
283
284 #ifndef CONFIG_INLINE_WRITE_TRYLOCK
_raw_write_trylock(rwlock_t * lock)285 int __lockfunc _raw_write_trylock(rwlock_t *lock)
286 {
287 return __raw_write_trylock(lock);
288 }
289 EXPORT_SYMBOL(_raw_write_trylock);
290 #endif
291
292 #ifndef CONFIG_INLINE_WRITE_LOCK
_raw_write_lock(rwlock_t * lock)293 void __lockfunc _raw_write_lock(rwlock_t *lock)
294 {
295 __raw_write_lock(lock);
296 }
297 EXPORT_SYMBOL(_raw_write_lock);
298 #endif
299
300 #ifndef CONFIG_INLINE_WRITE_LOCK_IRQSAVE
_raw_write_lock_irqsave(rwlock_t * lock)301 unsigned long __lockfunc _raw_write_lock_irqsave(rwlock_t *lock)
302 {
303 return __raw_write_lock_irqsave(lock);
304 }
305 EXPORT_SYMBOL(_raw_write_lock_irqsave);
306 #endif
307
308 #ifndef CONFIG_INLINE_WRITE_LOCK_IRQ
_raw_write_lock_irq(rwlock_t * lock)309 void __lockfunc _raw_write_lock_irq(rwlock_t *lock)
310 {
311 __raw_write_lock_irq(lock);
312 }
313 EXPORT_SYMBOL(_raw_write_lock_irq);
314 #endif
315
316 #ifndef CONFIG_INLINE_WRITE_LOCK_BH
_raw_write_lock_bh(rwlock_t * lock)317 void __lockfunc _raw_write_lock_bh(rwlock_t *lock)
318 {
319 __raw_write_lock_bh(lock);
320 }
321 EXPORT_SYMBOL(_raw_write_lock_bh);
322 #endif
323
324 #ifndef CONFIG_INLINE_WRITE_UNLOCK
_raw_write_unlock(rwlock_t * lock)325 void __lockfunc _raw_write_unlock(rwlock_t *lock)
326 {
327 __raw_write_unlock(lock);
328 }
329 EXPORT_SYMBOL(_raw_write_unlock);
330 #endif
331
332 #ifndef CONFIG_INLINE_WRITE_UNLOCK_IRQRESTORE
_raw_write_unlock_irqrestore(rwlock_t * lock,unsigned long flags)333 void __lockfunc _raw_write_unlock_irqrestore(rwlock_t *lock, unsigned long flags)
334 {
335 __raw_write_unlock_irqrestore(lock, flags);
336 }
337 EXPORT_SYMBOL(_raw_write_unlock_irqrestore);
338 #endif
339
340 #ifndef CONFIG_INLINE_WRITE_UNLOCK_IRQ
_raw_write_unlock_irq(rwlock_t * lock)341 void __lockfunc _raw_write_unlock_irq(rwlock_t *lock)
342 {
343 __raw_write_unlock_irq(lock);
344 }
345 EXPORT_SYMBOL(_raw_write_unlock_irq);
346 #endif
347
348 #ifndef CONFIG_INLINE_WRITE_UNLOCK_BH
_raw_write_unlock_bh(rwlock_t * lock)349 void __lockfunc _raw_write_unlock_bh(rwlock_t *lock)
350 {
351 __raw_write_unlock_bh(lock);
352 }
353 EXPORT_SYMBOL(_raw_write_unlock_bh);
354 #endif
355
356 #ifdef CONFIG_DEBUG_LOCK_ALLOC
357
_raw_spin_lock_nested(raw_spinlock_t * lock,int subclass)358 void __lockfunc _raw_spin_lock_nested(raw_spinlock_t *lock, int subclass)
359 {
360 preempt_disable();
361 spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
362 LOCK_CONTENDED(lock, do_raw_spin_trylock, do_raw_spin_lock);
363 }
364 EXPORT_SYMBOL(_raw_spin_lock_nested);
365
_raw_spin_lock_irqsave_nested(raw_spinlock_t * lock,int subclass)366 unsigned long __lockfunc _raw_spin_lock_irqsave_nested(raw_spinlock_t *lock,
367 int subclass)
368 {
369 unsigned long flags;
370
371 local_irq_save(flags);
372 preempt_disable();
373 spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
374 LOCK_CONTENDED_FLAGS(lock, do_raw_spin_trylock, do_raw_spin_lock,
375 do_raw_spin_lock_flags, &flags);
376 return flags;
377 }
378 EXPORT_SYMBOL(_raw_spin_lock_irqsave_nested);
379
_raw_spin_lock_nest_lock(raw_spinlock_t * lock,struct lockdep_map * nest_lock)380 void __lockfunc _raw_spin_lock_nest_lock(raw_spinlock_t *lock,
381 struct lockdep_map *nest_lock)
382 {
383 preempt_disable();
384 spin_acquire_nest(&lock->dep_map, 0, 0, nest_lock, _RET_IP_);
385 LOCK_CONTENDED(lock, do_raw_spin_trylock, do_raw_spin_lock);
386 }
387 EXPORT_SYMBOL(_raw_spin_lock_nest_lock);
388
389 #endif
390
in_lock_functions(unsigned long addr)391 notrace int in_lock_functions(unsigned long addr)
392 {
393 /* Linker adds these: start and end of __lockfunc functions */
394 extern char __lock_text_start[], __lock_text_end[];
395
396 return addr >= (unsigned long)__lock_text_start
397 && addr < (unsigned long)__lock_text_end;
398 }
399 EXPORT_SYMBOL(in_lock_functions);
400
