projects/linux·blob v7.2 · refs

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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (2004) Linus Torvalds
4 *
5 * Author: Zwane Mwaikambo <[email protected]>
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
27DEFINE_PER_CPU(struct mmiowb_state, __mmiowb_state);
28EXPORT_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) \
68static 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 \
81static 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 \
100static void __lockfunc __raw_##op##_lock_irq(locktype##_t *lock) \
101 lock_ctx_op(lock) \
102{ \
103 _raw_##op##_lock_irqsave(lock); \
104} \
105 \
106static 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 */
130BUILD_LOCK_OPS(spin, raw_spinlock, __acquires);
131
132#ifndef CONFIG_PREEMPT_RT
133BUILD_LOCK_OPS(read, rwlock, __acquires_shared);
134BUILD_LOCK_OPS(write, rwlock, __acquires);
135#endif
136
137#endif
138
139#ifndef CONFIG_INLINE_SPIN_TRYLOCK
140noinline int __lockfunc _raw_spin_trylock(raw_spinlock_t *lock)
141{
142 return __raw_spin_trylock(lock);
143}
144EXPORT_SYMBOL(_raw_spin_trylock);
145#endif
146
147#ifndef CONFIG_INLINE_SPIN_TRYLOCK_BH
148noinline int __lockfunc _raw_spin_trylock_bh(raw_spinlock_t *lock)
149{
150 return __raw_spin_trylock_bh(lock);
151}
152EXPORT_SYMBOL(_raw_spin_trylock_bh);
153#endif
154
155#ifndef CONFIG_INLINE_SPIN_LOCK
156noinline void __lockfunc _raw_spin_lock(raw_spinlock_t *lock)
157{
158 __raw_spin_lock(lock);
159}
160EXPORT_SYMBOL(_raw_spin_lock);
161#endif
162
163#ifndef CONFIG_INLINE_SPIN_LOCK_IRQSAVE
164noinline unsigned long __lockfunc _raw_spin_lock_irqsave(raw_spinlock_t *lock)
165{
166 return __raw_spin_lock_irqsave(lock);
167}
168EXPORT_SYMBOL(_raw_spin_lock_irqsave);
169#endif
170
171#ifndef CONFIG_INLINE_SPIN_LOCK_IRQ
172noinline void __lockfunc _raw_spin_lock_irq(raw_spinlock_t *lock)
173{
174 __raw_spin_lock_irq(lock);
175}
176EXPORT_SYMBOL(_raw_spin_lock_irq);
177#endif
178
179#ifndef CONFIG_INLINE_SPIN_LOCK_BH
180noinline void __lockfunc _raw_spin_lock_bh(raw_spinlock_t *lock)
181{
182 __raw_spin_lock_bh(lock);
183}
184EXPORT_SYMBOL(_raw_spin_lock_bh);
185#endif
186
187#ifdef CONFIG_UNINLINE_SPIN_UNLOCK
188noinline void __lockfunc _raw_spin_unlock(raw_spinlock_t *lock)
189{
190 __raw_spin_unlock(lock);
191}
192EXPORT_SYMBOL(_raw_spin_unlock);
193#endif
194
195#ifndef CONFIG_INLINE_SPIN_UNLOCK_IRQRESTORE
196noinline void __lockfunc _raw_spin_unlock_irqrestore(raw_spinlock_t *lock, unsigned long flags)
197{
198 __raw_spin_unlock_irqrestore(lock, flags);
199}
200EXPORT_SYMBOL(_raw_spin_unlock_irqrestore);
201#endif
202
203#ifndef CONFIG_INLINE_SPIN_UNLOCK_IRQ
204noinline void __lockfunc _raw_spin_unlock_irq(raw_spinlock_t *lock)
205{
206 __raw_spin_unlock_irq(lock);
207}
208EXPORT_SYMBOL(_raw_spin_unlock_irq);
209#endif
210
211#ifndef CONFIG_INLINE_SPIN_UNLOCK_BH
212noinline void __lockfunc _raw_spin_unlock_bh(raw_spinlock_t *lock)
213{
214 __raw_spin_unlock_bh(lock);
215}
216EXPORT_SYMBOL(_raw_spin_unlock_bh);
217#endif
218
219#ifndef CONFIG_PREEMPT_RT
220
221#ifndef CONFIG_INLINE_READ_TRYLOCK
222noinline int __lockfunc _raw_read_trylock(rwlock_t *lock)
223{
224 return __raw_read_trylock(lock);
225}
226EXPORT_SYMBOL(_raw_read_trylock);
227#endif
228
229#ifndef CONFIG_INLINE_READ_LOCK
230noinline void __lockfunc _raw_read_lock(rwlock_t *lock)
231{
232 __raw_read_lock(lock);
233}
234EXPORT_SYMBOL(_raw_read_lock);
235#endif
236
237#ifndef CONFIG_INLINE_READ_LOCK_IRQSAVE
238noinline unsigned long __lockfunc _raw_read_lock_irqsave(rwlock_t *lock)
239{
240 return __raw_read_lock_irqsave(lock);
241}
242EXPORT_SYMBOL(_raw_read_lock_irqsave);
243#endif
244
245#ifndef CONFIG_INLINE_READ_LOCK_IRQ
246noinline void __lockfunc _raw_read_lock_irq(rwlock_t *lock)
247{
248 __raw_read_lock_irq(lock);
249}
250EXPORT_SYMBOL(_raw_read_lock_irq);
251#endif
252
253#ifndef CONFIG_INLINE_READ_LOCK_BH
254noinline void __lockfunc _raw_read_lock_bh(rwlock_t *lock)
255{
256 __raw_read_lock_bh(lock);
257}
258EXPORT_SYMBOL(_raw_read_lock_bh);
259#endif
260
261#ifndef CONFIG_INLINE_READ_UNLOCK
262noinline void __lockfunc _raw_read_unlock(rwlock_t *lock)
263{
264 __raw_read_unlock(lock);
265}
266EXPORT_SYMBOL(_raw_read_unlock);
267#endif
268
269#ifndef CONFIG_INLINE_READ_UNLOCK_IRQRESTORE
270noinline void __lockfunc _raw_read_unlock_irqrestore(rwlock_t *lock, unsigned long flags)
271{
272 __raw_read_unlock_irqrestore(lock, flags);
273}
274EXPORT_SYMBOL(_raw_read_unlock_irqrestore);
275#endif
276
277#ifndef CONFIG_INLINE_READ_UNLOCK_IRQ
278noinline void __lockfunc _raw_read_unlock_irq(rwlock_t *lock)
279{
280 __raw_read_unlock_irq(lock);
281}
282EXPORT_SYMBOL(_raw_read_unlock_irq);
283#endif
284
285#ifndef CONFIG_INLINE_READ_UNLOCK_BH
286noinline void __lockfunc _raw_read_unlock_bh(rwlock_t *lock)
287{
288 __raw_read_unlock_bh(lock);
289}
290EXPORT_SYMBOL(_raw_read_unlock_bh);
291#endif
292
293#ifndef CONFIG_INLINE_WRITE_TRYLOCK
294noinline int __lockfunc _raw_write_trylock(rwlock_t *lock)
295{
296 return __raw_write_trylock(lock);
297}
298EXPORT_SYMBOL(_raw_write_trylock);
299#endif
300
301#ifndef CONFIG_INLINE_WRITE_LOCK
302noinline void __lockfunc _raw_write_lock(rwlock_t *lock)
303{
304 __raw_write_lock(lock);
305}
306EXPORT_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
312void __lockfunc _raw_write_lock_nested(rwlock_t *lock, int subclass)
313{
314 __raw_write_lock_nested(lock, subclass);
315}
316EXPORT_SYMBOL(_raw_write_lock_nested);
317#endif
318
319#ifndef CONFIG_INLINE_WRITE_LOCK_IRQSAVE
320noinline unsigned long __lockfunc _raw_write_lock_irqsave(rwlock_t *lock)
321{
322 return __raw_write_lock_irqsave(lock);
323}
324EXPORT_SYMBOL(_raw_write_lock_irqsave);
325#endif
326
327#ifndef CONFIG_INLINE_WRITE_LOCK_IRQ
328noinline void __lockfunc _raw_write_lock_irq(rwlock_t *lock)
329{
330 __raw_write_lock_irq(lock);
331}
332EXPORT_SYMBOL(_raw_write_lock_irq);
333#endif
334
335#ifndef CONFIG_INLINE_WRITE_LOCK_BH
336noinline void __lockfunc _raw_write_lock_bh(rwlock_t *lock)
337{
338 __raw_write_lock_bh(lock);
339}
340EXPORT_SYMBOL(_raw_write_lock_bh);
341#endif
342
343#ifndef CONFIG_INLINE_WRITE_UNLOCK
344noinline void __lockfunc _raw_write_unlock(rwlock_t *lock)
345{
346 __raw_write_unlock(lock);
347}
348EXPORT_SYMBOL(_raw_write_unlock);
349#endif
350
351#ifndef CONFIG_INLINE_WRITE_UNLOCK_IRQRESTORE
352noinline void __lockfunc _raw_write_unlock_irqrestore(rwlock_t *lock, unsigned long flags)
353{
354 __raw_write_unlock_irqrestore(lock, flags);
355}
356EXPORT_SYMBOL(_raw_write_unlock_irqrestore);
357#endif
358
359#ifndef CONFIG_INLINE_WRITE_UNLOCK_IRQ
360noinline void __lockfunc _raw_write_unlock_irq(rwlock_t *lock)
361{
362 __raw_write_unlock_irq(lock);
363}
364EXPORT_SYMBOL(_raw_write_unlock_irq);
365#endif
366
367#ifndef CONFIG_INLINE_WRITE_UNLOCK_BH
368noinline void __lockfunc _raw_write_unlock_bh(rwlock_t *lock)
369{
370 __raw_write_unlock_bh(lock);
371}
372EXPORT_SYMBOL(_raw_write_unlock_bh);
373#endif
374
375#endif /* !CONFIG_PREEMPT_RT */
376
377#ifdef CONFIG_DEBUG_LOCK_ALLOC
378
379void __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}
385EXPORT_SYMBOL(_raw_spin_lock_nested);
386
387unsigned 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}
398EXPORT_SYMBOL(_raw_spin_lock_irqsave_nested);
399
400void __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}
407EXPORT_SYMBOL(_raw_spin_lock_nest_lock);
408
409#endif
410
411notrace 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}
419EXPORT_SYMBOL(in_lock_functions);
420
421#if defined(CONFIG_PROVE_LOCKING) && defined(CONFIG_PREEMPT_RT)
422void notrace lockdep_assert_in_softirq_func(void)
423{
424 lockdep_assert_in_softirq();
425}
426EXPORT_SYMBOL(lockdep_assert_in_softirq_func);
427#endif