xref: /openbmc/linux/kernel/locking/spinlock.c (revision 9aeaf5bc)
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)					\
68 void __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 									\
80 unsigned 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 									\
98 void __lockfunc __raw_##op##_lock_irq(locktype##_t *lock)		\
99 {									\
100 	_raw_##op##_lock_irqsave(lock);					\
101 }									\
102 									\
103 void __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  */
126 BUILD_LOCK_OPS(spin, raw_spinlock);
127 
128 #ifndef CONFIG_PREEMPT_RT
129 BUILD_LOCK_OPS(read, rwlock);
130 BUILD_LOCK_OPS(write, rwlock);
131 #endif
132 
133 #endif
134 
135 #ifndef CONFIG_INLINE_SPIN_TRYLOCK
_raw_spin_trylock(raw_spinlock_t * lock)136 noinline int __lockfunc _raw_spin_trylock(raw_spinlock_t *lock)
137 {
138 	return __raw_spin_trylock(lock);
139 }
140 EXPORT_SYMBOL(_raw_spin_trylock);
141 #endif
142 
143 #ifndef CONFIG_INLINE_SPIN_TRYLOCK_BH
_raw_spin_trylock_bh(raw_spinlock_t * lock)144 noinline int __lockfunc _raw_spin_trylock_bh(raw_spinlock_t *lock)
145 {
146 	return __raw_spin_trylock_bh(lock);
147 }
148 EXPORT_SYMBOL(_raw_spin_trylock_bh);
149 #endif
150 
151 #ifndef CONFIG_INLINE_SPIN_LOCK
_raw_spin_lock(raw_spinlock_t * lock)152 noinline void __lockfunc _raw_spin_lock(raw_spinlock_t *lock)
153 {
154 	__raw_spin_lock(lock);
155 }
156 EXPORT_SYMBOL(_raw_spin_lock);
157 #endif
158 
159 #ifndef CONFIG_INLINE_SPIN_LOCK_IRQSAVE
_raw_spin_lock_irqsave(raw_spinlock_t * lock)160 noinline unsigned long __lockfunc _raw_spin_lock_irqsave(raw_spinlock_t *lock)
161 {
162 	return __raw_spin_lock_irqsave(lock);
163 }
164 EXPORT_SYMBOL(_raw_spin_lock_irqsave);
165 #endif
166 
167 #ifndef CONFIG_INLINE_SPIN_LOCK_IRQ
_raw_spin_lock_irq(raw_spinlock_t * lock)168 noinline void __lockfunc _raw_spin_lock_irq(raw_spinlock_t *lock)
169 {
170 	__raw_spin_lock_irq(lock);
171 }
172 EXPORT_SYMBOL(_raw_spin_lock_irq);
173 #endif
174 
175 #ifndef CONFIG_INLINE_SPIN_LOCK_BH
_raw_spin_lock_bh(raw_spinlock_t * lock)176 noinline void __lockfunc _raw_spin_lock_bh(raw_spinlock_t *lock)
177 {
178 	__raw_spin_lock_bh(lock);
179 }
180 EXPORT_SYMBOL(_raw_spin_lock_bh);
181 #endif
182 
183 #ifdef CONFIG_UNINLINE_SPIN_UNLOCK
_raw_spin_unlock(raw_spinlock_t * lock)184 noinline void __lockfunc _raw_spin_unlock(raw_spinlock_t *lock)
185 {
186 	__raw_spin_unlock(lock);
187 }
188 EXPORT_SYMBOL(_raw_spin_unlock);
189 #endif
190 
191 #ifndef CONFIG_INLINE_SPIN_UNLOCK_IRQRESTORE
_raw_spin_unlock_irqrestore(raw_spinlock_t * lock,unsigned long flags)192 noinline void __lockfunc _raw_spin_unlock_irqrestore(raw_spinlock_t *lock, unsigned long flags)
193 {
194 	__raw_spin_unlock_irqrestore(lock, flags);
195 }
196 EXPORT_SYMBOL(_raw_spin_unlock_irqrestore);
197 #endif
198 
199 #ifndef CONFIG_INLINE_SPIN_UNLOCK_IRQ
_raw_spin_unlock_irq(raw_spinlock_t * lock)200 noinline void __lockfunc _raw_spin_unlock_irq(raw_spinlock_t *lock)
201 {
202 	__raw_spin_unlock_irq(lock);
203 }
204 EXPORT_SYMBOL(_raw_spin_unlock_irq);
205 #endif
206 
207 #ifndef CONFIG_INLINE_SPIN_UNLOCK_BH
_raw_spin_unlock_bh(raw_spinlock_t * lock)208 noinline void __lockfunc _raw_spin_unlock_bh(raw_spinlock_t *lock)
209 {
210 	__raw_spin_unlock_bh(lock);
211 }
212 EXPORT_SYMBOL(_raw_spin_unlock_bh);
213 #endif
214 
215 #ifndef CONFIG_PREEMPT_RT
216 
217 #ifndef CONFIG_INLINE_READ_TRYLOCK
_raw_read_trylock(rwlock_t * lock)218 noinline int __lockfunc _raw_read_trylock(rwlock_t *lock)
219 {
220 	return __raw_read_trylock(lock);
221 }
222 EXPORT_SYMBOL(_raw_read_trylock);
223 #endif
224 
225 #ifndef CONFIG_INLINE_READ_LOCK
_raw_read_lock(rwlock_t * lock)226 noinline void __lockfunc _raw_read_lock(rwlock_t *lock)
227 {
228 	__raw_read_lock(lock);
229 }
230 EXPORT_SYMBOL(_raw_read_lock);
231 #endif
232 
233 #ifndef CONFIG_INLINE_READ_LOCK_IRQSAVE
_raw_read_lock_irqsave(rwlock_t * lock)234 noinline unsigned long __lockfunc _raw_read_lock_irqsave(rwlock_t *lock)
235 {
236 	return __raw_read_lock_irqsave(lock);
237 }
238 EXPORT_SYMBOL(_raw_read_lock_irqsave);
239 #endif
240 
241 #ifndef CONFIG_INLINE_READ_LOCK_IRQ
_raw_read_lock_irq(rwlock_t * lock)242 noinline void __lockfunc _raw_read_lock_irq(rwlock_t *lock)
243 {
244 	__raw_read_lock_irq(lock);
245 }
246 EXPORT_SYMBOL(_raw_read_lock_irq);
247 #endif
248 
249 #ifndef CONFIG_INLINE_READ_LOCK_BH
_raw_read_lock_bh(rwlock_t * lock)250 noinline void __lockfunc _raw_read_lock_bh(rwlock_t *lock)
251 {
252 	__raw_read_lock_bh(lock);
253 }
254 EXPORT_SYMBOL(_raw_read_lock_bh);
255 #endif
256 
257 #ifndef CONFIG_INLINE_READ_UNLOCK
_raw_read_unlock(rwlock_t * lock)258 noinline void __lockfunc _raw_read_unlock(rwlock_t *lock)
259 {
260 	__raw_read_unlock(lock);
261 }
262 EXPORT_SYMBOL(_raw_read_unlock);
263 #endif
264 
265 #ifndef CONFIG_INLINE_READ_UNLOCK_IRQRESTORE
_raw_read_unlock_irqrestore(rwlock_t * lock,unsigned long flags)266 noinline void __lockfunc _raw_read_unlock_irqrestore(rwlock_t *lock, unsigned long flags)
267 {
268 	__raw_read_unlock_irqrestore(lock, flags);
269 }
270 EXPORT_SYMBOL(_raw_read_unlock_irqrestore);
271 #endif
272 
273 #ifndef CONFIG_INLINE_READ_UNLOCK_IRQ
_raw_read_unlock_irq(rwlock_t * lock)274 noinline void __lockfunc _raw_read_unlock_irq(rwlock_t *lock)
275 {
276 	__raw_read_unlock_irq(lock);
277 }
278 EXPORT_SYMBOL(_raw_read_unlock_irq);
279 #endif
280 
281 #ifndef CONFIG_INLINE_READ_UNLOCK_BH
_raw_read_unlock_bh(rwlock_t * lock)282 noinline void __lockfunc _raw_read_unlock_bh(rwlock_t *lock)
283 {
284 	__raw_read_unlock_bh(lock);
285 }
286 EXPORT_SYMBOL(_raw_read_unlock_bh);
287 #endif
288 
289 #ifndef CONFIG_INLINE_WRITE_TRYLOCK
_raw_write_trylock(rwlock_t * lock)290 noinline int __lockfunc _raw_write_trylock(rwlock_t *lock)
291 {
292 	return __raw_write_trylock(lock);
293 }
294 EXPORT_SYMBOL(_raw_write_trylock);
295 #endif
296 
297 #ifndef CONFIG_INLINE_WRITE_LOCK
_raw_write_lock(rwlock_t * lock)298 noinline void __lockfunc _raw_write_lock(rwlock_t *lock)
299 {
300 	__raw_write_lock(lock);
301 }
302 EXPORT_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 
_raw_write_lock_nested(rwlock_t * lock,int subclass)308 void __lockfunc _raw_write_lock_nested(rwlock_t *lock, int subclass)
309 {
310 	__raw_write_lock_nested(lock, subclass);
311 }
312 EXPORT_SYMBOL(_raw_write_lock_nested);
313 #endif
314 
315 #ifndef CONFIG_INLINE_WRITE_LOCK_IRQSAVE
_raw_write_lock_irqsave(rwlock_t * lock)316 noinline unsigned long __lockfunc _raw_write_lock_irqsave(rwlock_t *lock)
317 {
318 	return __raw_write_lock_irqsave(lock);
319 }
320 EXPORT_SYMBOL(_raw_write_lock_irqsave);
321 #endif
322 
323 #ifndef CONFIG_INLINE_WRITE_LOCK_IRQ
_raw_write_lock_irq(rwlock_t * lock)324 noinline void __lockfunc _raw_write_lock_irq(rwlock_t *lock)
325 {
326 	__raw_write_lock_irq(lock);
327 }
328 EXPORT_SYMBOL(_raw_write_lock_irq);
329 #endif
330 
331 #ifndef CONFIG_INLINE_WRITE_LOCK_BH
_raw_write_lock_bh(rwlock_t * lock)332 noinline void __lockfunc _raw_write_lock_bh(rwlock_t *lock)
333 {
334 	__raw_write_lock_bh(lock);
335 }
336 EXPORT_SYMBOL(_raw_write_lock_bh);
337 #endif
338 
339 #ifndef CONFIG_INLINE_WRITE_UNLOCK
_raw_write_unlock(rwlock_t * lock)340 noinline void __lockfunc _raw_write_unlock(rwlock_t *lock)
341 {
342 	__raw_write_unlock(lock);
343 }
344 EXPORT_SYMBOL(_raw_write_unlock);
345 #endif
346 
347 #ifndef CONFIG_INLINE_WRITE_UNLOCK_IRQRESTORE
_raw_write_unlock_irqrestore(rwlock_t * lock,unsigned long flags)348 noinline void __lockfunc _raw_write_unlock_irqrestore(rwlock_t *lock, unsigned long flags)
349 {
350 	__raw_write_unlock_irqrestore(lock, flags);
351 }
352 EXPORT_SYMBOL(_raw_write_unlock_irqrestore);
353 #endif
354 
355 #ifndef CONFIG_INLINE_WRITE_UNLOCK_IRQ
_raw_write_unlock_irq(rwlock_t * lock)356 noinline void __lockfunc _raw_write_unlock_irq(rwlock_t *lock)
357 {
358 	__raw_write_unlock_irq(lock);
359 }
360 EXPORT_SYMBOL(_raw_write_unlock_irq);
361 #endif
362 
363 #ifndef CONFIG_INLINE_WRITE_UNLOCK_BH
_raw_write_unlock_bh(rwlock_t * lock)364 noinline void __lockfunc _raw_write_unlock_bh(rwlock_t *lock)
365 {
366 	__raw_write_unlock_bh(lock);
367 }
368 EXPORT_SYMBOL(_raw_write_unlock_bh);
369 #endif
370 
371 #endif /* !CONFIG_PREEMPT_RT */
372 
373 #ifdef CONFIG_DEBUG_LOCK_ALLOC
374 
_raw_spin_lock_nested(raw_spinlock_t * lock,int subclass)375 void __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 }
381 EXPORT_SYMBOL(_raw_spin_lock_nested);
382 
_raw_spin_lock_irqsave_nested(raw_spinlock_t * lock,int subclass)383 unsigned 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 }
394 EXPORT_SYMBOL(_raw_spin_lock_irqsave_nested);
395 
_raw_spin_lock_nest_lock(raw_spinlock_t * lock,struct lockdep_map * nest_lock)396 void __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 }
403 EXPORT_SYMBOL(_raw_spin_lock_nest_lock);
404 
405 #endif
406 
in_lock_functions(unsigned long addr)407 notrace 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 }
415 EXPORT_SYMBOL(in_lock_functions);
416