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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/* No rwlock_t variants for now, so just build this function by hand */
133static void __lockfunc __raw_spin_lock_irq_disable(raw_spinlock_t *lock)
134{
135 for (;;) {
136 preempt_disable();
137 local_interrupt_disable();
138 if (likely(do_raw_spin_trylock(lock)))
139 break;
140 local_interrupt_enable();
141 preempt_enable();
142
143 arch_spin_relax(&lock->raw_lock);
144 }
145}
146
147#ifndef CONFIG_PREEMPT_RT
148BUILD_LOCK_OPS(read, rwlock, __acquires_shared);
149BUILD_LOCK_OPS(write, rwlock, __acquires);
150#endif
151
152#endif
153
154#ifndef CONFIG_INLINE_SPIN_TRYLOCK
155noinline int __lockfunc _raw_spin_trylock(raw_spinlock_t *lock)
156{
157 return __raw_spin_trylock(lock);
158}
159EXPORT_SYMBOL(_raw_spin_trylock);
160#endif
161
162#ifndef CONFIG_INLINE_SPIN_TRYLOCK_BH
163noinline int __lockfunc _raw_spin_trylock_bh(raw_spinlock_t *lock)
164{
165 return __raw_spin_trylock_bh(lock);
166}
167EXPORT_SYMBOL(_raw_spin_trylock_bh);
168#endif
169
170#ifndef CONFIG_INLINE_SPIN_LOCK
171noinline void __lockfunc _raw_spin_lock(raw_spinlock_t *lock)
172{
173 __raw_spin_lock(lock);
174}
175EXPORT_SYMBOL(_raw_spin_lock);
176#endif
177
178#ifndef CONFIG_INLINE_SPIN_LOCK_IRQSAVE
179noinline unsigned long __lockfunc _raw_spin_lock_irqsave(raw_spinlock_t *lock)
180{
181 return __raw_spin_lock_irqsave(lock);
182}
183EXPORT_SYMBOL(_raw_spin_lock_irqsave);
184#endif
185
186#ifndef CONFIG_INLINE_SPIN_LOCK_IRQ
187noinline void __lockfunc _raw_spin_lock_irq(raw_spinlock_t *lock)
188{
189 __raw_spin_lock_irq(lock);
190}
191EXPORT_SYMBOL(_raw_spin_lock_irq);
192#endif
193
194#ifndef CONFIG_INLINE_SPIN_LOCK_IRQ
195noinline void __lockfunc _raw_spin_lock_irq_disable(raw_spinlock_t *lock)
196{
197 __raw_spin_lock_irq_disable(lock);
198}
199EXPORT_SYMBOL_GPL(_raw_spin_lock_irq_disable);
200#endif
201
202#ifndef CONFIG_INLINE_SPIN_LOCK_BH
203noinline void __lockfunc _raw_spin_lock_bh(raw_spinlock_t *lock)
204{
205 __raw_spin_lock_bh(lock);
206}
207EXPORT_SYMBOL(_raw_spin_lock_bh);
208#endif
209
210#ifdef CONFIG_UNINLINE_SPIN_UNLOCK
211noinline void __lockfunc _raw_spin_unlock(raw_spinlock_t *lock)
212{
213 __raw_spin_unlock(lock);
214}
215EXPORT_SYMBOL(_raw_spin_unlock);
216#endif
217
218#ifndef CONFIG_INLINE_SPIN_UNLOCK_IRQRESTORE
219noinline void __lockfunc _raw_spin_unlock_irqrestore(raw_spinlock_t *lock, unsigned long flags)
220{
221 __raw_spin_unlock_irqrestore(lock, flags);
222}
223EXPORT_SYMBOL(_raw_spin_unlock_irqrestore);
224#endif
225
226#ifndef CONFIG_INLINE_SPIN_UNLOCK_IRQ
227noinline void __lockfunc _raw_spin_unlock_irq(raw_spinlock_t *lock)
228{
229 __raw_spin_unlock_irq(lock);
230}
231EXPORT_SYMBOL(_raw_spin_unlock_irq);
232#endif
233
234#ifndef CONFIG_INLINE_SPIN_UNLOCK_IRQ
235noinline void __lockfunc _raw_spin_unlock_irq_enable(raw_spinlock_t *lock)
236{
237 __raw_spin_unlock_irq_enable(lock);
238}
239EXPORT_SYMBOL_GPL(_raw_spin_unlock_irq_enable);
240#endif
241
242#ifndef CONFIG_INLINE_SPIN_UNLOCK_BH
243noinline void __lockfunc _raw_spin_unlock_bh(raw_spinlock_t *lock)
244{
245 __raw_spin_unlock_bh(lock);
246}
247EXPORT_SYMBOL(_raw_spin_unlock_bh);
248#endif
249
250#ifndef CONFIG_PREEMPT_RT
251
252#ifndef CONFIG_INLINE_READ_TRYLOCK
253noinline int __lockfunc _raw_read_trylock(rwlock_t *lock)
254{
255 return __raw_read_trylock(lock);
256}
257EXPORT_SYMBOL(_raw_read_trylock);
258#endif
259
260#ifndef CONFIG_INLINE_READ_LOCK
261noinline void __lockfunc _raw_read_lock(rwlock_t *lock)
262{
263 __raw_read_lock(lock);
264}
265EXPORT_SYMBOL(_raw_read_lock);
266#endif
267
268#ifndef CONFIG_INLINE_READ_LOCK_IRQSAVE
269noinline unsigned long __lockfunc _raw_read_lock_irqsave(rwlock_t *lock)
270{
271 return __raw_read_lock_irqsave(lock);
272}
273EXPORT_SYMBOL(_raw_read_lock_irqsave);
274#endif
275
276#ifndef CONFIG_INLINE_READ_LOCK_IRQ
277noinline void __lockfunc _raw_read_lock_irq(rwlock_t *lock)
278{
279 __raw_read_lock_irq(lock);
280}
281EXPORT_SYMBOL(_raw_read_lock_irq);
282#endif
283
284#ifndef CONFIG_INLINE_READ_LOCK_BH
285noinline void __lockfunc _raw_read_lock_bh(rwlock_t *lock)
286{
287 __raw_read_lock_bh(lock);
288}
289EXPORT_SYMBOL(_raw_read_lock_bh);
290#endif
291
292#ifndef CONFIG_INLINE_READ_UNLOCK
293noinline void __lockfunc _raw_read_unlock(rwlock_t *lock)
294{
295 __raw_read_unlock(lock);
296}
297EXPORT_SYMBOL(_raw_read_unlock);
298#endif
299
300#ifndef CONFIG_INLINE_READ_UNLOCK_IRQRESTORE
301noinline void __lockfunc _raw_read_unlock_irqrestore(rwlock_t *lock, unsigned long flags)
302{
303 __raw_read_unlock_irqrestore(lock, flags);
304}
305EXPORT_SYMBOL(_raw_read_unlock_irqrestore);
306#endif
307
308#ifndef CONFIG_INLINE_READ_UNLOCK_IRQ
309noinline void __lockfunc _raw_read_unlock_irq(rwlock_t *lock)
310{
311 __raw_read_unlock_irq(lock);
312}
313EXPORT_SYMBOL(_raw_read_unlock_irq);
314#endif
315
316#ifndef CONFIG_INLINE_READ_UNLOCK_BH
317noinline void __lockfunc _raw_read_unlock_bh(rwlock_t *lock)
318{
319 __raw_read_unlock_bh(lock);
320}
321EXPORT_SYMBOL(_raw_read_unlock_bh);
322#endif
323
324#ifndef CONFIG_INLINE_WRITE_TRYLOCK
325noinline int __lockfunc _raw_write_trylock(rwlock_t *lock)
326{
327 return __raw_write_trylock(lock);
328}
329EXPORT_SYMBOL(_raw_write_trylock);
330#endif
331
332#ifndef CONFIG_INLINE_WRITE_LOCK
333noinline void __lockfunc _raw_write_lock(rwlock_t *lock)
334{
335 __raw_write_lock(lock);
336}
337EXPORT_SYMBOL(_raw_write_lock);
338
339#ifndef CONFIG_DEBUG_LOCK_ALLOC
340#define __raw_write_lock_nested(lock, subclass) __raw_write_lock(((void)(subclass), (lock)))
341#endif
342
343void __lockfunc _raw_write_lock_nested(rwlock_t *lock, int subclass)
344{
345 __raw_write_lock_nested(lock, subclass);
346}
347EXPORT_SYMBOL(_raw_write_lock_nested);
348#endif
349
350#ifndef CONFIG_INLINE_WRITE_LOCK_IRQSAVE
351noinline unsigned long __lockfunc _raw_write_lock_irqsave(rwlock_t *lock)
352{
353 return __raw_write_lock_irqsave(lock);
354}
355EXPORT_SYMBOL(_raw_write_lock_irqsave);
356#endif
357
358#ifndef CONFIG_INLINE_WRITE_LOCK_IRQ
359noinline void __lockfunc _raw_write_lock_irq(rwlock_t *lock)
360{
361 __raw_write_lock_irq(lock);
362}
363EXPORT_SYMBOL(_raw_write_lock_irq);
364#endif
365
366#ifndef CONFIG_INLINE_WRITE_LOCK_BH
367noinline void __lockfunc _raw_write_lock_bh(rwlock_t *lock)
368{
369 __raw_write_lock_bh(lock);
370}
371EXPORT_SYMBOL(_raw_write_lock_bh);
372#endif
373
374#ifndef CONFIG_INLINE_WRITE_UNLOCK
375noinline void __lockfunc _raw_write_unlock(rwlock_t *lock)
376{
377 __raw_write_unlock(lock);
378}
379EXPORT_SYMBOL(_raw_write_unlock);
380#endif
381
382#ifndef CONFIG_INLINE_WRITE_UNLOCK_IRQRESTORE
383noinline void __lockfunc _raw_write_unlock_irqrestore(rwlock_t *lock, unsigned long flags)
384{
385 __raw_write_unlock_irqrestore(lock, flags);
386}
387EXPORT_SYMBOL(_raw_write_unlock_irqrestore);
388#endif
389
390#ifndef CONFIG_INLINE_WRITE_UNLOCK_IRQ
391noinline void __lockfunc _raw_write_unlock_irq(rwlock_t *lock)
392{
393 __raw_write_unlock_irq(lock);
394}
395EXPORT_SYMBOL(_raw_write_unlock_irq);
396#endif
397
398#ifndef CONFIG_INLINE_WRITE_UNLOCK_BH
399noinline void __lockfunc _raw_write_unlock_bh(rwlock_t *lock)
400{
401 __raw_write_unlock_bh(lock);
402}
403EXPORT_SYMBOL(_raw_write_unlock_bh);
404#endif
405
406#endif /* !CONFIG_PREEMPT_RT */
407
408#ifdef CONFIG_DEBUG_LOCK_ALLOC
409
410void __lockfunc _raw_spin_lock_nested(raw_spinlock_t *lock, int subclass)
411{
412 preempt_disable();
413 spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
414 LOCK_CONTENDED(lock, do_raw_spin_trylock, do_raw_spin_lock);
415}
416EXPORT_SYMBOL(_raw_spin_lock_nested);
417
418unsigned long __lockfunc _raw_spin_lock_irqsave_nested(raw_spinlock_t *lock,
419 int subclass)
420{
421 unsigned long flags;
422
423 local_irq_save(flags);
424 preempt_disable();
425 spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
426 LOCK_CONTENDED(lock, do_raw_spin_trylock, do_raw_spin_lock);
427 return flags;
428}
429EXPORT_SYMBOL(_raw_spin_lock_irqsave_nested);
430
431void __lockfunc _raw_spin_lock_nest_lock(raw_spinlock_t *lock,
432 struct lockdep_map *nest_lock)
433{
434 preempt_disable();
435 spin_acquire_nest(&lock->dep_map, 0, 0, nest_lock, _RET_IP_);
436 LOCK_CONTENDED(lock, do_raw_spin_trylock, do_raw_spin_lock);
437}
438EXPORT_SYMBOL(_raw_spin_lock_nest_lock);
439
440#endif
441
442notrace int in_lock_functions(unsigned long addr)
443{
444 /* Linker adds these: start and end of __lockfunc functions */
445 extern char __lock_text_start[], __lock_text_end[];
446
447 return addr >= (unsigned long)__lock_text_start
448 && addr < (unsigned long)__lock_text_end;
449}
450EXPORT_SYMBOL(in_lock_functions);
451
452#if defined(CONFIG_PROVE_LOCKING) && defined(CONFIG_PREEMPT_RT)
453void notrace lockdep_assert_in_softirq_func(void)
454{
455 lockdep_assert_in_softirq();
456}
457EXPORT_SYMBOL(lockdep_assert_in_softirq_func);
458#endif