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