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