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-rw-r--r--include/linux/spinlock.h606
1 files changed, 606 insertions, 0 deletions
diff --git a/include/linux/spinlock.h b/include/linux/spinlock.h
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+++ b/include/linux/spinlock.h
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1#ifndef __LINUX_SPINLOCK_H
2#define __LINUX_SPINLOCK_H
3
4/*
5 * include/linux/spinlock.h - generic locking declarations
6 */
7
8#include <linux/config.h>
9#include <linux/preempt.h>
10#include <linux/linkage.h>
11#include <linux/compiler.h>
12#include <linux/thread_info.h>
13#include <linux/kernel.h>
14#include <linux/stringify.h>
15
16#include <asm/processor.h> /* for cpu relax */
17#include <asm/system.h>
18
19/*
20 * Must define these before including other files, inline functions need them
21 */
22#define LOCK_SECTION_NAME \
23 ".text.lock." __stringify(KBUILD_BASENAME)
24
25#define LOCK_SECTION_START(extra) \
26 ".subsection 1\n\t" \
27 extra \
28 ".ifndef " LOCK_SECTION_NAME "\n\t" \
29 LOCK_SECTION_NAME ":\n\t" \
30 ".endif\n"
31
32#define LOCK_SECTION_END \
33 ".previous\n\t"
34
35#define __lockfunc fastcall __attribute__((section(".spinlock.text")))
36
37/*
38 * If CONFIG_SMP is set, pull in the _raw_* definitions
39 */
40#ifdef CONFIG_SMP
41
42#define assert_spin_locked(x) BUG_ON(!spin_is_locked(x))
43#include <asm/spinlock.h>
44
45int __lockfunc _spin_trylock(spinlock_t *lock);
46int __lockfunc _read_trylock(rwlock_t *lock);
47int __lockfunc _write_trylock(rwlock_t *lock);
48
49void __lockfunc _spin_lock(spinlock_t *lock) __acquires(spinlock_t);
50void __lockfunc _read_lock(rwlock_t *lock) __acquires(rwlock_t);
51void __lockfunc _write_lock(rwlock_t *lock) __acquires(rwlock_t);
52
53void __lockfunc _spin_unlock(spinlock_t *lock) __releases(spinlock_t);
54void __lockfunc _read_unlock(rwlock_t *lock) __releases(rwlock_t);
55void __lockfunc _write_unlock(rwlock_t *lock) __releases(rwlock_t);
56
57unsigned long __lockfunc _spin_lock_irqsave(spinlock_t *lock) __acquires(spinlock_t);
58unsigned long __lockfunc _read_lock_irqsave(rwlock_t *lock) __acquires(rwlock_t);
59unsigned long __lockfunc _write_lock_irqsave(rwlock_t *lock) __acquires(rwlock_t);
60
61void __lockfunc _spin_lock_irq(spinlock_t *lock) __acquires(spinlock_t);
62void __lockfunc _spin_lock_bh(spinlock_t *lock) __acquires(spinlock_t);
63void __lockfunc _read_lock_irq(rwlock_t *lock) __acquires(rwlock_t);
64void __lockfunc _read_lock_bh(rwlock_t *lock) __acquires(rwlock_t);
65void __lockfunc _write_lock_irq(rwlock_t *lock) __acquires(rwlock_t);
66void __lockfunc _write_lock_bh(rwlock_t *lock) __acquires(rwlock_t);
67
68void __lockfunc _spin_unlock_irqrestore(spinlock_t *lock, unsigned long flags) __releases(spinlock_t);
69void __lockfunc _spin_unlock_irq(spinlock_t *lock) __releases(spinlock_t);
70void __lockfunc _spin_unlock_bh(spinlock_t *lock) __releases(spinlock_t);
71void __lockfunc _read_unlock_irqrestore(rwlock_t *lock, unsigned long flags) __releases(rwlock_t);
72void __lockfunc _read_unlock_irq(rwlock_t *lock) __releases(rwlock_t);
73void __lockfunc _read_unlock_bh(rwlock_t *lock) __releases(rwlock_t);
74void __lockfunc _write_unlock_irqrestore(rwlock_t *lock, unsigned long flags) __releases(rwlock_t);
75void __lockfunc _write_unlock_irq(rwlock_t *lock) __releases(rwlock_t);
76void __lockfunc _write_unlock_bh(rwlock_t *lock) __releases(rwlock_t);
77
78int __lockfunc _spin_trylock_bh(spinlock_t *lock);
79int __lockfunc generic_raw_read_trylock(rwlock_t *lock);
80int in_lock_functions(unsigned long addr);
81
82#else
83
84#define in_lock_functions(ADDR) 0
85
86#if !defined(CONFIG_PREEMPT) && !defined(CONFIG_DEBUG_SPINLOCK)
87# define _atomic_dec_and_lock(atomic,lock) atomic_dec_and_test(atomic)
88# define ATOMIC_DEC_AND_LOCK
89#endif
90
91#ifdef CONFIG_DEBUG_SPINLOCK
92
93#define SPINLOCK_MAGIC 0x1D244B3C
94typedef struct {
95 unsigned long magic;
96 volatile unsigned long lock;
97 volatile unsigned int babble;
98 const char *module;
99 char *owner;
100 int oline;
101} spinlock_t;
102#define SPIN_LOCK_UNLOCKED (spinlock_t) { SPINLOCK_MAGIC, 0, 10, __FILE__ , NULL, 0}
103
104#define spin_lock_init(x) \
105 do { \
106 (x)->magic = SPINLOCK_MAGIC; \
107 (x)->lock = 0; \
108 (x)->babble = 5; \
109 (x)->module = __FILE__; \
110 (x)->owner = NULL; \
111 (x)->oline = 0; \
112 } while (0)
113
114#define CHECK_LOCK(x) \
115 do { \
116 if ((x)->magic != SPINLOCK_MAGIC) { \
117 printk(KERN_ERR "%s:%d: spin_is_locked on uninitialized spinlock %p.\n", \
118 __FILE__, __LINE__, (x)); \
119 } \
120 } while(0)
121
122#define _raw_spin_lock(x) \
123 do { \
124 CHECK_LOCK(x); \
125 if ((x)->lock&&(x)->babble) { \
126 (x)->babble--; \
127 printk("%s:%d: spin_lock(%s:%p) already locked by %s/%d\n", \
128 __FILE__,__LINE__, (x)->module, \
129 (x), (x)->owner, (x)->oline); \
130 } \
131 (x)->lock = 1; \
132 (x)->owner = __FILE__; \
133 (x)->oline = __LINE__; \
134 } while (0)
135
136/* without debugging, spin_is_locked on UP always says
137 * FALSE. --> printk if already locked. */
138#define spin_is_locked(x) \
139 ({ \
140 CHECK_LOCK(x); \
141 if ((x)->lock&&(x)->babble) { \
142 (x)->babble--; \
143 printk("%s:%d: spin_is_locked(%s:%p) already locked by %s/%d\n", \
144 __FILE__,__LINE__, (x)->module, \
145 (x), (x)->owner, (x)->oline); \
146 } \
147 0; \
148 })
149
150/* with debugging, assert_spin_locked() on UP does check
151 * the lock value properly */
152#define assert_spin_locked(x) \
153 ({ \
154 CHECK_LOCK(x); \
155 BUG_ON(!(x)->lock); \
156 })
157
158/* without debugging, spin_trylock on UP always says
159 * TRUE. --> printk if already locked. */
160#define _raw_spin_trylock(x) \
161 ({ \
162 CHECK_LOCK(x); \
163 if ((x)->lock&&(x)->babble) { \
164 (x)->babble--; \
165 printk("%s:%d: spin_trylock(%s:%p) already locked by %s/%d\n", \
166 __FILE__,__LINE__, (x)->module, \
167 (x), (x)->owner, (x)->oline); \
168 } \
169 (x)->lock = 1; \
170 (x)->owner = __FILE__; \
171 (x)->oline = __LINE__; \
172 1; \
173 })
174
175#define spin_unlock_wait(x) \
176 do { \
177 CHECK_LOCK(x); \
178 if ((x)->lock&&(x)->babble) { \
179 (x)->babble--; \
180 printk("%s:%d: spin_unlock_wait(%s:%p) owned by %s/%d\n", \
181 __FILE__,__LINE__, (x)->module, (x), \
182 (x)->owner, (x)->oline); \
183 }\
184 } while (0)
185
186#define _raw_spin_unlock(x) \
187 do { \
188 CHECK_LOCK(x); \
189 if (!(x)->lock&&(x)->babble) { \
190 (x)->babble--; \
191 printk("%s:%d: spin_unlock(%s:%p) not locked\n", \
192 __FILE__,__LINE__, (x)->module, (x));\
193 } \
194 (x)->lock = 0; \
195 } while (0)
196#else
197/*
198 * gcc versions before ~2.95 have a nasty bug with empty initializers.
199 */
200#if (__GNUC__ > 2)
201 typedef struct { } spinlock_t;
202 #define SPIN_LOCK_UNLOCKED (spinlock_t) { }
203#else
204 typedef struct { int gcc_is_buggy; } spinlock_t;
205 #define SPIN_LOCK_UNLOCKED (spinlock_t) { 0 }
206#endif
207
208/*
209 * If CONFIG_SMP is unset, declare the _raw_* definitions as nops
210 */
211#define spin_lock_init(lock) do { (void)(lock); } while(0)
212#define _raw_spin_lock(lock) do { (void)(lock); } while(0)
213#define spin_is_locked(lock) ((void)(lock), 0)
214#define assert_spin_locked(lock) do { (void)(lock); } while(0)
215#define _raw_spin_trylock(lock) (((void)(lock), 1))
216#define spin_unlock_wait(lock) (void)(lock)
217#define _raw_spin_unlock(lock) do { (void)(lock); } while(0)
218#endif /* CONFIG_DEBUG_SPINLOCK */
219
220/* RW spinlocks: No debug version */
221
222#if (__GNUC__ > 2)
223 typedef struct { } rwlock_t;
224 #define RW_LOCK_UNLOCKED (rwlock_t) { }
225#else
226 typedef struct { int gcc_is_buggy; } rwlock_t;
227 #define RW_LOCK_UNLOCKED (rwlock_t) { 0 }
228#endif
229
230#define rwlock_init(lock) do { (void)(lock); } while(0)
231#define _raw_read_lock(lock) do { (void)(lock); } while(0)
232#define _raw_read_unlock(lock) do { (void)(lock); } while(0)
233#define _raw_write_lock(lock) do { (void)(lock); } while(0)
234#define _raw_write_unlock(lock) do { (void)(lock); } while(0)
235#define read_can_lock(lock) (((void)(lock), 1))
236#define write_can_lock(lock) (((void)(lock), 1))
237#define _raw_read_trylock(lock) ({ (void)(lock); (1); })
238#define _raw_write_trylock(lock) ({ (void)(lock); (1); })
239
240#define _spin_trylock(lock) ({preempt_disable(); _raw_spin_trylock(lock) ? \
241 1 : ({preempt_enable(); 0;});})
242
243#define _read_trylock(lock) ({preempt_disable();_raw_read_trylock(lock) ? \
244 1 : ({preempt_enable(); 0;});})
245
246#define _write_trylock(lock) ({preempt_disable(); _raw_write_trylock(lock) ? \
247 1 : ({preempt_enable(); 0;});})
248
249#define _spin_trylock_bh(lock) ({preempt_disable(); local_bh_disable(); \
250 _raw_spin_trylock(lock) ? \
251 1 : ({preempt_enable(); local_bh_enable(); 0;});})
252
253#define _spin_lock(lock) \
254do { \
255 preempt_disable(); \
256 _raw_spin_lock(lock); \
257 __acquire(lock); \
258} while(0)
259
260#define _write_lock(lock) \
261do { \
262 preempt_disable(); \
263 _raw_write_lock(lock); \
264 __acquire(lock); \
265} while(0)
266
267#define _read_lock(lock) \
268do { \
269 preempt_disable(); \
270 _raw_read_lock(lock); \
271 __acquire(lock); \
272} while(0)
273
274#define _spin_unlock(lock) \
275do { \
276 _raw_spin_unlock(lock); \
277 preempt_enable(); \
278 __release(lock); \
279} while (0)
280
281#define _write_unlock(lock) \
282do { \
283 _raw_write_unlock(lock); \
284 preempt_enable(); \
285 __release(lock); \
286} while(0)
287
288#define _read_unlock(lock) \
289do { \
290 _raw_read_unlock(lock); \
291 preempt_enable(); \
292 __release(lock); \
293} while(0)
294
295#define _spin_lock_irqsave(lock, flags) \
296do { \
297 local_irq_save(flags); \
298 preempt_disable(); \
299 _raw_spin_lock(lock); \
300 __acquire(lock); \
301} while (0)
302
303#define _spin_lock_irq(lock) \
304do { \
305 local_irq_disable(); \
306 preempt_disable(); \
307 _raw_spin_lock(lock); \
308 __acquire(lock); \
309} while (0)
310
311#define _spin_lock_bh(lock) \
312do { \
313 local_bh_disable(); \
314 preempt_disable(); \
315 _raw_spin_lock(lock); \
316 __acquire(lock); \
317} while (0)
318
319#define _read_lock_irqsave(lock, flags) \
320do { \
321 local_irq_save(flags); \
322 preempt_disable(); \
323 _raw_read_lock(lock); \
324 __acquire(lock); \
325} while (0)
326
327#define _read_lock_irq(lock) \
328do { \
329 local_irq_disable(); \
330 preempt_disable(); \
331 _raw_read_lock(lock); \
332 __acquire(lock); \
333} while (0)
334
335#define _read_lock_bh(lock) \
336do { \
337 local_bh_disable(); \
338 preempt_disable(); \
339 _raw_read_lock(lock); \
340 __acquire(lock); \
341} while (0)
342
343#define _write_lock_irqsave(lock, flags) \
344do { \
345 local_irq_save(flags); \
346 preempt_disable(); \
347 _raw_write_lock(lock); \
348 __acquire(lock); \
349} while (0)
350
351#define _write_lock_irq(lock) \
352do { \
353 local_irq_disable(); \
354 preempt_disable(); \
355 _raw_write_lock(lock); \
356 __acquire(lock); \
357} while (0)
358
359#define _write_lock_bh(lock) \
360do { \
361 local_bh_disable(); \
362 preempt_disable(); \
363 _raw_write_lock(lock); \
364 __acquire(lock); \
365} while (0)
366
367#define _spin_unlock_irqrestore(lock, flags) \
368do { \
369 _raw_spin_unlock(lock); \
370 local_irq_restore(flags); \
371 preempt_enable(); \
372 __release(lock); \
373} while (0)
374
375#define _spin_unlock_irq(lock) \
376do { \
377 _raw_spin_unlock(lock); \
378 local_irq_enable(); \
379 preempt_enable(); \
380 __release(lock); \
381} while (0)
382
383#define _spin_unlock_bh(lock) \
384do { \
385 _raw_spin_unlock(lock); \
386 preempt_enable(); \
387 local_bh_enable(); \
388 __release(lock); \
389} while (0)
390
391#define _write_unlock_bh(lock) \
392do { \
393 _raw_write_unlock(lock); \
394 preempt_enable(); \
395 local_bh_enable(); \
396 __release(lock); \
397} while (0)
398
399#define _read_unlock_irqrestore(lock, flags) \
400do { \
401 _raw_read_unlock(lock); \
402 local_irq_restore(flags); \
403 preempt_enable(); \
404 __release(lock); \
405} while (0)
406
407#define _write_unlock_irqrestore(lock, flags) \
408do { \
409 _raw_write_unlock(lock); \
410 local_irq_restore(flags); \
411 preempt_enable(); \
412 __release(lock); \
413} while (0)
414
415#define _read_unlock_irq(lock) \
416do { \
417 _raw_read_unlock(lock); \
418 local_irq_enable(); \
419 preempt_enable(); \
420 __release(lock); \
421} while (0)
422
423#define _read_unlock_bh(lock) \
424do { \
425 _raw_read_unlock(lock); \
426 local_bh_enable(); \
427 preempt_enable(); \
428 __release(lock); \
429} while (0)
430
431#define _write_unlock_irq(lock) \
432do { \
433 _raw_write_unlock(lock); \
434 local_irq_enable(); \
435 preempt_enable(); \
436 __release(lock); \
437} while (0)
438
439#endif /* !SMP */
440
441/*
442 * Define the various spin_lock and rw_lock methods. Note we define these
443 * regardless of whether CONFIG_SMP or CONFIG_PREEMPT are set. The various
444 * methods are defined as nops in the case they are not required.
445 */
446#define spin_trylock(lock) __cond_lock(_spin_trylock(lock))
447#define read_trylock(lock) __cond_lock(_read_trylock(lock))
448#define write_trylock(lock) __cond_lock(_write_trylock(lock))
449
450#define spin_lock(lock) _spin_lock(lock)
451#define write_lock(lock) _write_lock(lock)
452#define read_lock(lock) _read_lock(lock)
453
454#ifdef CONFIG_SMP
455#define spin_lock_irqsave(lock, flags) flags = _spin_lock_irqsave(lock)
456#define read_lock_irqsave(lock, flags) flags = _read_lock_irqsave(lock)
457#define write_lock_irqsave(lock, flags) flags = _write_lock_irqsave(lock)
458#else
459#define spin_lock_irqsave(lock, flags) _spin_lock_irqsave(lock, flags)
460#define read_lock_irqsave(lock, flags) _read_lock_irqsave(lock, flags)
461#define write_lock_irqsave(lock, flags) _write_lock_irqsave(lock, flags)
462#endif
463
464#define spin_lock_irq(lock) _spin_lock_irq(lock)
465#define spin_lock_bh(lock) _spin_lock_bh(lock)
466
467#define read_lock_irq(lock) _read_lock_irq(lock)
468#define read_lock_bh(lock) _read_lock_bh(lock)
469
470#define write_lock_irq(lock) _write_lock_irq(lock)
471#define write_lock_bh(lock) _write_lock_bh(lock)
472
473#define spin_unlock(lock) _spin_unlock(lock)
474#define write_unlock(lock) _write_unlock(lock)
475#define read_unlock(lock) _read_unlock(lock)
476
477#define spin_unlock_irqrestore(lock, flags) _spin_unlock_irqrestore(lock, flags)
478#define spin_unlock_irq(lock) _spin_unlock_irq(lock)
479#define spin_unlock_bh(lock) _spin_unlock_bh(lock)
480
481#define read_unlock_irqrestore(lock, flags) _read_unlock_irqrestore(lock, flags)
482#define read_unlock_irq(lock) _read_unlock_irq(lock)
483#define read_unlock_bh(lock) _read_unlock_bh(lock)
484
485#define write_unlock_irqrestore(lock, flags) _write_unlock_irqrestore(lock, flags)
486#define write_unlock_irq(lock) _write_unlock_irq(lock)
487#define write_unlock_bh(lock) _write_unlock_bh(lock)
488
489#define spin_trylock_bh(lock) __cond_lock(_spin_trylock_bh(lock))
490
491#define spin_trylock_irq(lock) \
492({ \
493 local_irq_disable(); \
494 _spin_trylock(lock) ? \
495 1 : ({local_irq_enable(); 0; }); \
496})
497
498#define spin_trylock_irqsave(lock, flags) \
499({ \
500 local_irq_save(flags); \
501 _spin_trylock(lock) ? \
502 1 : ({local_irq_restore(flags); 0;}); \
503})
504
505#ifdef CONFIG_LOCKMETER
506extern void _metered_spin_lock (spinlock_t *lock);
507extern void _metered_spin_unlock (spinlock_t *lock);
508extern int _metered_spin_trylock(spinlock_t *lock);
509extern void _metered_read_lock (rwlock_t *lock);
510extern void _metered_read_unlock (rwlock_t *lock);
511extern void _metered_write_lock (rwlock_t *lock);
512extern void _metered_write_unlock (rwlock_t *lock);
513extern int _metered_read_trylock (rwlock_t *lock);
514extern int _metered_write_trylock(rwlock_t *lock);
515#endif
516
517/* "lock on reference count zero" */
518#ifndef ATOMIC_DEC_AND_LOCK
519#include <asm/atomic.h>
520extern int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock);
521#endif
522
523#define atomic_dec_and_lock(atomic,lock) __cond_lock(_atomic_dec_and_lock(atomic,lock))
524
525/*
526 * bit-based spin_lock()
527 *
528 * Don't use this unless you really need to: spin_lock() and spin_unlock()
529 * are significantly faster.
530 */
531static inline void bit_spin_lock(int bitnum, unsigned long *addr)
532{
533 /*
534 * Assuming the lock is uncontended, this never enters
535 * the body of the outer loop. If it is contended, then
536 * within the inner loop a non-atomic test is used to
537 * busywait with less bus contention for a good time to
538 * attempt to acquire the lock bit.
539 */
540 preempt_disable();
541#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
542 while (test_and_set_bit(bitnum, addr)) {
543 while (test_bit(bitnum, addr)) {
544 preempt_enable();
545 cpu_relax();
546 preempt_disable();
547 }
548 }
549#endif
550 __acquire(bitlock);
551}
552
553/*
554 * Return true if it was acquired
555 */
556static inline int bit_spin_trylock(int bitnum, unsigned long *addr)
557{
558 preempt_disable();
559#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
560 if (test_and_set_bit(bitnum, addr)) {
561 preempt_enable();
562 return 0;
563 }
564#endif
565 __acquire(bitlock);
566 return 1;
567}
568
569/*
570 * bit-based spin_unlock()
571 */
572static inline void bit_spin_unlock(int bitnum, unsigned long *addr)
573{
574#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
575 BUG_ON(!test_bit(bitnum, addr));
576 smp_mb__before_clear_bit();
577 clear_bit(bitnum, addr);
578#endif
579 preempt_enable();
580 __release(bitlock);
581}
582
583/*
584 * Return true if the lock is held.
585 */
586static inline int bit_spin_is_locked(int bitnum, unsigned long *addr)
587{
588#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
589 return test_bit(bitnum, addr);
590#elif defined CONFIG_PREEMPT
591 return preempt_count();
592#else
593 return 1;
594#endif
595}
596
597#define DEFINE_SPINLOCK(x) spinlock_t x = SPIN_LOCK_UNLOCKED
598#define DEFINE_RWLOCK(x) rwlock_t x = RW_LOCK_UNLOCKED
599
600/**
601 * spin_can_lock - would spin_trylock() succeed?
602 * @lock: the spinlock in question.
603 */
604#define spin_can_lock(lock) (!spin_is_locked(lock))
605
606#endif /* __LINUX_SPINLOCK_H */