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 embeds 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 preemptible 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, lock_ctx_op) \
68 static void __lockfunc __raw_##op##_lock(locktype##_t *lock) \
69 lock_ctx_op(lock) \
70 { \
71 for (;;) { \
72 preempt_disable(); \
73 if (likely(do_raw_##op##_trylock(lock))) \
74 break; \
75 preempt_enable(); \
76 \
77 arch_##op##_relax(&lock->raw_lock); \
78 } \
79 } \
80 \
81 static unsigned long __lockfunc __raw_##op##_lock_irqsave(locktype##_t *lock) \
82 lock_ctx_op(lock) \
83 { \
84 unsigned long flags; \
85 \
86 for (;;) { \
87 preempt_disable(); \
88 local_irq_save(flags); \
89 if (likely(do_raw_##op##_trylock(lock))) \
90 break; \
91 local_irq_restore(flags); \
92 preempt_enable(); \
93 \
94 arch_##op##_relax(&lock->raw_lock); \
95 } \
96 \
97 return flags; \
98 } \
99 \
100 static void __lockfunc __raw_##op##_lock_irq(locktype##_t *lock) \
101 lock_ctx_op(lock) \
102 { \
103 _raw_##op##_lock_irqsave(lock); \
104 } \
105 \
106 static void __lockfunc __raw_##op##_lock_bh(locktype##_t *lock) \
107 lock_ctx_op(lock) \
108 { \
109 unsigned long flags; \
110 \
111 /* */ \
112 /* Careful: we must exclude softirqs too, hence the */ \
113 /* irq-disabling. We use the generic preemption-aware */ \
114 /* function: */ \
115 /**/ \
116 flags = _raw_##op##_lock_irqsave(lock); \
117 local_bh_disable(); \
118 local_irq_restore(flags); \
119 } \
120
121 /*
122 * Build preemption-friendly versions of the following
123 * lock-spinning functions:
124 *
125 * __[spin|read|write]_lock()
126 * __[spin|read|write]_lock_irq()
127 * __[spin|read|write]_lock_irqsave()
128 * __[spin|read|write]_lock_bh()
129 */
130 BUILD_LOCK_OPS(spin, raw_spinlock, __acquires);
131
132 #ifndef CONFIG_PREEMPT_RT
133 BUILD_LOCK_OPS(read, rwlock, __acquires_shared);
134 BUILD_LOCK_OPS(write, rwlock, __acquires);
135 #endif
136
137 #endif
138
139 #ifndef CONFIG_INLINE_SPIN_TRYLOCK
_raw_spin_trylock(raw_spinlock_t * lock)140 noinline int __lockfunc _raw_spin_trylock(raw_spinlock_t *lock)
141 {
142 return __raw_spin_trylock(lock);
143 }
144 EXPORT_SYMBOL(_raw_spin_trylock);
145 #endif
146
147 #ifndef CONFIG_INLINE_SPIN_TRYLOCK_BH
_raw_spin_trylock_bh(raw_spinlock_t * lock)148 noinline int __lockfunc _raw_spin_trylock_bh(raw_spinlock_t *lock)
149 {
150 return __raw_spin_trylock_bh(lock);
151 }
152 EXPORT_SYMBOL(_raw_spin_trylock_bh);
153 #endif
154
155 #ifndef CONFIG_INLINE_SPIN_LOCK
_raw_spin_lock(raw_spinlock_t * lock)156 noinline void __lockfunc _raw_spin_lock(raw_spinlock_t *lock)
157 {
158 __raw_spin_lock(lock);
159 }
160 EXPORT_SYMBOL(_raw_spin_lock);
161 #endif
162
163 #ifndef CONFIG_INLINE_SPIN_LOCK_IRQSAVE
_raw_spin_lock_irqsave(raw_spinlock_t * lock)164 noinline unsigned long __lockfunc _raw_spin_lock_irqsave(raw_spinlock_t *lock)
165 {
166 return __raw_spin_lock_irqsave(lock);
167 }
168 EXPORT_SYMBOL(_raw_spin_lock_irqsave);
169 #endif
170
171 #ifndef CONFIG_INLINE_SPIN_LOCK_IRQ
_raw_spin_lock_irq(raw_spinlock_t * lock)172 noinline void __lockfunc _raw_spin_lock_irq(raw_spinlock_t *lock)
173 {
174 __raw_spin_lock_irq(lock);
175 }
176 EXPORT_SYMBOL(_raw_spin_lock_irq);
177 #endif
178
179 #ifndef CONFIG_INLINE_SPIN_LOCK_BH
_raw_spin_lock_bh(raw_spinlock_t * lock)180 noinline void __lockfunc _raw_spin_lock_bh(raw_spinlock_t *lock)
181 {
182 __raw_spin_lock_bh(lock);
183 }
184 EXPORT_SYMBOL(_raw_spin_lock_bh);
185 #endif
186
187 #ifdef CONFIG_UNINLINE_SPIN_UNLOCK
_raw_spin_unlock(raw_spinlock_t * lock)188 noinline void __lockfunc _raw_spin_unlock(raw_spinlock_t *lock)
189 {
190 __raw_spin_unlock(lock);
191 }
192 EXPORT_SYMBOL(_raw_spin_unlock);
193 #endif
194
195 #ifndef CONFIG_INLINE_SPIN_UNLOCK_IRQRESTORE
_raw_spin_unlock_irqrestore(raw_spinlock_t * lock,unsigned long flags)196 noinline void __lockfunc _raw_spin_unlock_irqrestore(raw_spinlock_t *lock, unsigned long flags)
197 {
198 __raw_spin_unlock_irqrestore(lock, flags);
199 }
200 EXPORT_SYMBOL(_raw_spin_unlock_irqrestore);
201 #endif
202
203 #ifndef CONFIG_INLINE_SPIN_UNLOCK_IRQ
_raw_spin_unlock_irq(raw_spinlock_t * lock)204 noinline void __lockfunc _raw_spin_unlock_irq(raw_spinlock_t *lock)
205 {
206 __raw_spin_unlock_irq(lock);
207 }
208 EXPORT_SYMBOL(_raw_spin_unlock_irq);
209 #endif
210
211 #ifndef CONFIG_INLINE_SPIN_UNLOCK_BH
_raw_spin_unlock_bh(raw_spinlock_t * lock)212 noinline void __lockfunc _raw_spin_unlock_bh(raw_spinlock_t *lock)
213 {
214 __raw_spin_unlock_bh(lock);
215 }
216 EXPORT_SYMBOL(_raw_spin_unlock_bh);
217 #endif
218
219 #ifndef CONFIG_PREEMPT_RT
220
221 #ifndef CONFIG_INLINE_READ_TRYLOCK
_raw_read_trylock(rwlock_t * lock)222 noinline int __lockfunc _raw_read_trylock(rwlock_t *lock)
223 {
224 return __raw_read_trylock(lock);
225 }
226 EXPORT_SYMBOL(_raw_read_trylock);
227 #endif
228
229 #ifndef CONFIG_INLINE_READ_LOCK
_raw_read_lock(rwlock_t * lock)230 noinline void __lockfunc _raw_read_lock(rwlock_t *lock)
231 {
232 __raw_read_lock(lock);
233 }
234 EXPORT_SYMBOL(_raw_read_lock);
235 #endif
236
237 #ifndef CONFIG_INLINE_READ_LOCK_IRQSAVE
_raw_read_lock_irqsave(rwlock_t * lock)238 noinline unsigned long __lockfunc _raw_read_lock_irqsave(rwlock_t *lock)
239 {
240 return __raw_read_lock_irqsave(lock);
241 }
242 EXPORT_SYMBOL(_raw_read_lock_irqsave);
243 #endif
244
245 #ifndef CONFIG_INLINE_READ_LOCK_IRQ
_raw_read_lock_irq(rwlock_t * lock)246 noinline void __lockfunc _raw_read_lock_irq(rwlock_t *lock)
247 {
248 __raw_read_lock_irq(lock);
249 }
250 EXPORT_SYMBOL(_raw_read_lock_irq);
251 #endif
252
253 #ifndef CONFIG_INLINE_READ_LOCK_BH
_raw_read_lock_bh(rwlock_t * lock)254 noinline void __lockfunc _raw_read_lock_bh(rwlock_t *lock)
255 {
256 __raw_read_lock_bh(lock);
257 }
258 EXPORT_SYMBOL(_raw_read_lock_bh);
259 #endif
260
261 #ifndef CONFIG_INLINE_READ_UNLOCK
_raw_read_unlock(rwlock_t * lock)262 noinline void __lockfunc _raw_read_unlock(rwlock_t *lock)
263 {
264 __raw_read_unlock(lock);
265 }
266 EXPORT_SYMBOL(_raw_read_unlock);
267 #endif
268
269 #ifndef CONFIG_INLINE_READ_UNLOCK_IRQRESTORE
_raw_read_unlock_irqrestore(rwlock_t * lock,unsigned long flags)270 noinline void __lockfunc _raw_read_unlock_irqrestore(rwlock_t *lock, unsigned long flags)
271 {
272 __raw_read_unlock_irqrestore(lock, flags);
273 }
274 EXPORT_SYMBOL(_raw_read_unlock_irqrestore);
275 #endif
276
277 #ifndef CONFIG_INLINE_READ_UNLOCK_IRQ
_raw_read_unlock_irq(rwlock_t * lock)278 noinline void __lockfunc _raw_read_unlock_irq(rwlock_t *lock)
279 {
280 __raw_read_unlock_irq(lock);
281 }
282 EXPORT_SYMBOL(_raw_read_unlock_irq);
283 #endif
284
285 #ifndef CONFIG_INLINE_READ_UNLOCK_BH
_raw_read_unlock_bh(rwlock_t * lock)286 noinline void __lockfunc _raw_read_unlock_bh(rwlock_t *lock)
287 {
288 __raw_read_unlock_bh(lock);
289 }
290 EXPORT_SYMBOL(_raw_read_unlock_bh);
291 #endif
292
293 #ifndef CONFIG_INLINE_WRITE_TRYLOCK
_raw_write_trylock(rwlock_t * lock)294 noinline int __lockfunc _raw_write_trylock(rwlock_t *lock)
295 {
296 return __raw_write_trylock(lock);
297 }
298 EXPORT_SYMBOL(_raw_write_trylock);
299 #endif
300
301 #ifndef CONFIG_INLINE_WRITE_LOCK
_raw_write_lock(rwlock_t * lock)302 noinline void __lockfunc _raw_write_lock(rwlock_t *lock)
303 {
304 __raw_write_lock(lock);
305 }
306 EXPORT_SYMBOL(_raw_write_lock);
307
308 #ifndef CONFIG_DEBUG_LOCK_ALLOC
309 #define __raw_write_lock_nested(lock, subclass) __raw_write_lock(((void)(subclass), (lock)))
310 #endif
311
_raw_write_lock_nested(rwlock_t * lock,int subclass)312 void __lockfunc _raw_write_lock_nested(rwlock_t *lock, int subclass)
313 {
314 __raw_write_lock_nested(lock, subclass);
315 }
316 EXPORT_SYMBOL(_raw_write_lock_nested);
317 #endif
318
319 #ifndef CONFIG_INLINE_WRITE_LOCK_IRQSAVE
_raw_write_lock_irqsave(rwlock_t * lock)320 noinline unsigned long __lockfunc _raw_write_lock_irqsave(rwlock_t *lock)
321 {
322 return __raw_write_lock_irqsave(lock);
323 }
324 EXPORT_SYMBOL(_raw_write_lock_irqsave);
325 #endif
326
327 #ifndef CONFIG_INLINE_WRITE_LOCK_IRQ
_raw_write_lock_irq(rwlock_t * lock)328 noinline void __lockfunc _raw_write_lock_irq(rwlock_t *lock)
329 {
330 __raw_write_lock_irq(lock);
331 }
332 EXPORT_SYMBOL(_raw_write_lock_irq);
333 #endif
334
335 #ifndef CONFIG_INLINE_WRITE_LOCK_BH
_raw_write_lock_bh(rwlock_t * lock)336 noinline void __lockfunc _raw_write_lock_bh(rwlock_t *lock)
337 {
338 __raw_write_lock_bh(lock);
339 }
340 EXPORT_SYMBOL(_raw_write_lock_bh);
341 #endif
342
343 #ifndef CONFIG_INLINE_WRITE_UNLOCK
_raw_write_unlock(rwlock_t * lock)344 noinline void __lockfunc _raw_write_unlock(rwlock_t *lock)
345 {
346 __raw_write_unlock(lock);
347 }
348 EXPORT_SYMBOL(_raw_write_unlock);
349 #endif
350
351 #ifndef CONFIG_INLINE_WRITE_UNLOCK_IRQRESTORE
_raw_write_unlock_irqrestore(rwlock_t * lock,unsigned long flags)352 noinline void __lockfunc _raw_write_unlock_irqrestore(rwlock_t *lock, unsigned long flags)
353 {
354 __raw_write_unlock_irqrestore(lock, flags);
355 }
356 EXPORT_SYMBOL(_raw_write_unlock_irqrestore);
357 #endif
358
359 #ifndef CONFIG_INLINE_WRITE_UNLOCK_IRQ
_raw_write_unlock_irq(rwlock_t * lock)360 noinline void __lockfunc _raw_write_unlock_irq(rwlock_t *lock)
361 {
362 __raw_write_unlock_irq(lock);
363 }
364 EXPORT_SYMBOL(_raw_write_unlock_irq);
365 #endif
366
367 #ifndef CONFIG_INLINE_WRITE_UNLOCK_BH
_raw_write_unlock_bh(rwlock_t * lock)368 noinline void __lockfunc _raw_write_unlock_bh(rwlock_t *lock)
369 {
370 __raw_write_unlock_bh(lock);
371 }
372 EXPORT_SYMBOL(_raw_write_unlock_bh);
373 #endif
374
375 #endif /* !CONFIG_PREEMPT_RT */
376
377 #ifdef CONFIG_DEBUG_LOCK_ALLOC
378
_raw_spin_lock_nested(raw_spinlock_t * lock,int subclass)379 void __lockfunc _raw_spin_lock_nested(raw_spinlock_t *lock, int subclass)
380 {
381 preempt_disable();
382 spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
383 LOCK_CONTENDED(lock, do_raw_spin_trylock, do_raw_spin_lock);
384 }
385 EXPORT_SYMBOL(_raw_spin_lock_nested);
386
_raw_spin_lock_irqsave_nested(raw_spinlock_t * lock,int subclass)387 unsigned long __lockfunc _raw_spin_lock_irqsave_nested(raw_spinlock_t *lock,
388 int subclass)
389 {
390 unsigned long flags;
391
392 local_irq_save(flags);
393 preempt_disable();
394 spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
395 LOCK_CONTENDED(lock, do_raw_spin_trylock, do_raw_spin_lock);
396 return flags;
397 }
398 EXPORT_SYMBOL(_raw_spin_lock_irqsave_nested);
399
_raw_spin_lock_nest_lock(raw_spinlock_t * lock,struct lockdep_map * nest_lock)400 void __lockfunc _raw_spin_lock_nest_lock(raw_spinlock_t *lock,
401 struct lockdep_map *nest_lock)
402 {
403 preempt_disable();
404 spin_acquire_nest(&lock->dep_map, 0, 0, nest_lock, _RET_IP_);
405 LOCK_CONTENDED(lock, do_raw_spin_trylock, do_raw_spin_lock);
406 }
407 EXPORT_SYMBOL(_raw_spin_lock_nest_lock);
408
409 #endif
410
in_lock_functions(unsigned long addr)411 notrace int in_lock_functions(unsigned long addr)
412 {
413 /* Linker adds these: start and end of __lockfunc functions */
414 extern char __lock_text_start[], __lock_text_end[];
415
416 return addr >= (unsigned long)__lock_text_start
417 && addr < (unsigned long)__lock_text_end;
418 }
419 EXPORT_SYMBOL(in_lock_functions);
420
421 #if defined(CONFIG_PROVE_LOCKING) && defined(CONFIG_PREEMPT_RT)
lockdep_assert_in_softirq_func(void)422 void notrace lockdep_assert_in_softirq_func(void)
423 {
424 lockdep_assert_in_softirq();
425 }
426 EXPORT_SYMBOL(lockdep_assert_in_softirq_func);
427 #endif
428