spinlock.c 11 KB

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  1. /*
  2. * Copyright (2004) Linus Torvalds
  3. *
  4. * Author: Zwane Mwaikambo <zwane@fsmlabs.com>
  5. *
  6. * Copyright (2004, 2005) Ingo Molnar
  7. *
  8. * This file contains the spinlock/rwlock implementations for the
  9. * SMP and the DEBUG_SPINLOCK cases. (UP-nondebug inlines them)
  10. *
  11. * Note that some architectures have special knowledge about the
  12. * stack frames of these functions in their profile_pc. If you
  13. * change anything significant here that could change the stack
  14. * frame contact the architecture maintainers.
  15. */
  16. #include <linux/linkage.h>
  17. #include <linux/preempt.h>
  18. #include <linux/spinlock.h>
  19. #include <linux/interrupt.h>
  20. #include <linux/debug_locks.h>
  21. #include <linux/module.h>
  22. int __lockfunc _spin_trylock(spinlock_t *lock)
  23. {
  24. preempt_disable();
  25. if (_raw_spin_trylock(lock)) {
  26. spin_acquire(&lock->dep_map, 0, 1, _RET_IP_);
  27. return 1;
  28. }
  29. preempt_enable();
  30. return 0;
  31. }
  32. EXPORT_SYMBOL(_spin_trylock);
  33. int __lockfunc _read_trylock(rwlock_t *lock)
  34. {
  35. preempt_disable();
  36. if (_raw_read_trylock(lock)) {
  37. rwlock_acquire_read(&lock->dep_map, 0, 1, _RET_IP_);
  38. return 1;
  39. }
  40. preempt_enable();
  41. return 0;
  42. }
  43. EXPORT_SYMBOL(_read_trylock);
  44. int __lockfunc _write_trylock(rwlock_t *lock)
  45. {
  46. preempt_disable();
  47. if (_raw_write_trylock(lock)) {
  48. rwlock_acquire(&lock->dep_map, 0, 1, _RET_IP_);
  49. return 1;
  50. }
  51. preempt_enable();
  52. return 0;
  53. }
  54. EXPORT_SYMBOL(_write_trylock);
  55. /*
  56. * If lockdep is enabled then we use the non-preemption spin-ops
  57. * even on CONFIG_PREEMPT, because lockdep assumes that interrupts are
  58. * not re-enabled during lock-acquire (which the preempt-spin-ops do):
  59. */
  60. #if !defined(CONFIG_PREEMPT) || !defined(CONFIG_SMP) || \
  61. defined(CONFIG_DEBUG_LOCK_ALLOC)
  62. void __lockfunc _read_lock(rwlock_t *lock)
  63. {
  64. preempt_disable();
  65. rwlock_acquire_read(&lock->dep_map, 0, 0, _RET_IP_);
  66. _raw_read_lock(lock);
  67. }
  68. EXPORT_SYMBOL(_read_lock);
  69. unsigned long __lockfunc _spin_lock_irqsave(spinlock_t *lock)
  70. {
  71. unsigned long flags;
  72. local_irq_save(flags);
  73. preempt_disable();
  74. spin_acquire(&lock->dep_map, 0, 0, _RET_IP_);
  75. /*
  76. * On lockdep we dont want the hand-coded irq-enable of
  77. * _raw_spin_lock_flags() code, because lockdep assumes
  78. * that interrupts are not re-enabled during lock-acquire:
  79. */
  80. #ifdef CONFIG_PROVE_LOCKING
  81. _raw_spin_lock(lock);
  82. #else
  83. _raw_spin_lock_flags(lock, &flags);
  84. #endif
  85. return flags;
  86. }
  87. EXPORT_SYMBOL(_spin_lock_irqsave);
  88. void __lockfunc _spin_lock_irq(spinlock_t *lock)
  89. {
  90. local_irq_disable();
  91. preempt_disable();
  92. spin_acquire(&lock->dep_map, 0, 0, _RET_IP_);
  93. _raw_spin_lock(lock);
  94. }
  95. EXPORT_SYMBOL(_spin_lock_irq);
  96. void __lockfunc _spin_lock_bh(spinlock_t *lock)
  97. {
  98. local_bh_disable();
  99. preempt_disable();
  100. spin_acquire(&lock->dep_map, 0, 0, _RET_IP_);
  101. _raw_spin_lock(lock);
  102. }
  103. EXPORT_SYMBOL(_spin_lock_bh);
  104. unsigned long __lockfunc _read_lock_irqsave(rwlock_t *lock)
  105. {
  106. unsigned long flags;
  107. local_irq_save(flags);
  108. preempt_disable();
  109. rwlock_acquire_read(&lock->dep_map, 0, 0, _RET_IP_);
  110. _raw_read_lock(lock);
  111. return flags;
  112. }
  113. EXPORT_SYMBOL(_read_lock_irqsave);
  114. void __lockfunc _read_lock_irq(rwlock_t *lock)
  115. {
  116. local_irq_disable();
  117. preempt_disable();
  118. rwlock_acquire_read(&lock->dep_map, 0, 0, _RET_IP_);
  119. _raw_read_lock(lock);
  120. }
  121. EXPORT_SYMBOL(_read_lock_irq);
  122. void __lockfunc _read_lock_bh(rwlock_t *lock)
  123. {
  124. local_bh_disable();
  125. preempt_disable();
  126. rwlock_acquire_read(&lock->dep_map, 0, 0, _RET_IP_);
  127. _raw_read_lock(lock);
  128. }
  129. EXPORT_SYMBOL(_read_lock_bh);
  130. unsigned long __lockfunc _write_lock_irqsave(rwlock_t *lock)
  131. {
  132. unsigned long flags;
  133. local_irq_save(flags);
  134. preempt_disable();
  135. rwlock_acquire(&lock->dep_map, 0, 0, _RET_IP_);
  136. _raw_write_lock(lock);
  137. return flags;
  138. }
  139. EXPORT_SYMBOL(_write_lock_irqsave);
  140. void __lockfunc _write_lock_irq(rwlock_t *lock)
  141. {
  142. local_irq_disable();
  143. preempt_disable();
  144. rwlock_acquire(&lock->dep_map, 0, 0, _RET_IP_);
  145. _raw_write_lock(lock);
  146. }
  147. EXPORT_SYMBOL(_write_lock_irq);
  148. void __lockfunc _write_lock_bh(rwlock_t *lock)
  149. {
  150. local_bh_disable();
  151. preempt_disable();
  152. rwlock_acquire(&lock->dep_map, 0, 0, _RET_IP_);
  153. _raw_write_lock(lock);
  154. }
  155. EXPORT_SYMBOL(_write_lock_bh);
  156. void __lockfunc _spin_lock(spinlock_t *lock)
  157. {
  158. preempt_disable();
  159. spin_acquire(&lock->dep_map, 0, 0, _RET_IP_);
  160. _raw_spin_lock(lock);
  161. }
  162. EXPORT_SYMBOL(_spin_lock);
  163. void __lockfunc _write_lock(rwlock_t *lock)
  164. {
  165. preempt_disable();
  166. rwlock_acquire(&lock->dep_map, 0, 0, _RET_IP_);
  167. _raw_write_lock(lock);
  168. }
  169. EXPORT_SYMBOL(_write_lock);
  170. #else /* CONFIG_PREEMPT: */
  171. /*
  172. * This could be a long-held lock. We both prepare to spin for a long
  173. * time (making _this_ CPU preemptable if possible), and we also signal
  174. * towards that other CPU that it should break the lock ASAP.
  175. *
  176. * (We do this in a function because inlining it would be excessive.)
  177. */
  178. #define BUILD_LOCK_OPS(op, locktype) \
  179. void __lockfunc _##op##_lock(locktype##_t *lock) \
  180. { \
  181. for (;;) { \
  182. preempt_disable(); \
  183. if (likely(_raw_##op##_trylock(lock))) \
  184. break; \
  185. preempt_enable(); \
  186. \
  187. if (!(lock)->break_lock) \
  188. (lock)->break_lock = 1; \
  189. while (!op##_can_lock(lock) && (lock)->break_lock) \
  190. _raw_##op##_relax(&lock->raw_lock); \
  191. } \
  192. (lock)->break_lock = 0; \
  193. } \
  194. \
  195. EXPORT_SYMBOL(_##op##_lock); \
  196. \
  197. unsigned long __lockfunc _##op##_lock_irqsave(locktype##_t *lock) \
  198. { \
  199. unsigned long flags; \
  200. \
  201. for (;;) { \
  202. preempt_disable(); \
  203. local_irq_save(flags); \
  204. if (likely(_raw_##op##_trylock(lock))) \
  205. break; \
  206. local_irq_restore(flags); \
  207. preempt_enable(); \
  208. \
  209. if (!(lock)->break_lock) \
  210. (lock)->break_lock = 1; \
  211. while (!op##_can_lock(lock) && (lock)->break_lock) \
  212. _raw_##op##_relax(&lock->raw_lock); \
  213. } \
  214. (lock)->break_lock = 0; \
  215. return flags; \
  216. } \
  217. \
  218. EXPORT_SYMBOL(_##op##_lock_irqsave); \
  219. \
  220. void __lockfunc _##op##_lock_irq(locktype##_t *lock) \
  221. { \
  222. _##op##_lock_irqsave(lock); \
  223. } \
  224. \
  225. EXPORT_SYMBOL(_##op##_lock_irq); \
  226. \
  227. void __lockfunc _##op##_lock_bh(locktype##_t *lock) \
  228. { \
  229. unsigned long flags; \
  230. \
  231. /* */ \
  232. /* Careful: we must exclude softirqs too, hence the */ \
  233. /* irq-disabling. We use the generic preemption-aware */ \
  234. /* function: */ \
  235. /**/ \
  236. flags = _##op##_lock_irqsave(lock); \
  237. local_bh_disable(); \
  238. local_irq_restore(flags); \
  239. } \
  240. \
  241. EXPORT_SYMBOL(_##op##_lock_bh)
  242. /*
  243. * Build preemption-friendly versions of the following
  244. * lock-spinning functions:
  245. *
  246. * _[spin|read|write]_lock()
  247. * _[spin|read|write]_lock_irq()
  248. * _[spin|read|write]_lock_irqsave()
  249. * _[spin|read|write]_lock_bh()
  250. */
  251. BUILD_LOCK_OPS(spin, spinlock);
  252. BUILD_LOCK_OPS(read, rwlock);
  253. BUILD_LOCK_OPS(write, rwlock);
  254. #endif /* CONFIG_PREEMPT */
  255. #ifdef CONFIG_DEBUG_LOCK_ALLOC
  256. void __lockfunc _spin_lock_nested(spinlock_t *lock, int subclass)
  257. {
  258. preempt_disable();
  259. spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
  260. _raw_spin_lock(lock);
  261. }
  262. EXPORT_SYMBOL(_spin_lock_nested);
  263. unsigned long __lockfunc _spin_lock_irqsave_nested(spinlock_t *lock, int subclass)
  264. {
  265. unsigned long flags;
  266. local_irq_save(flags);
  267. preempt_disable();
  268. spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
  269. /*
  270. * On lockdep we dont want the hand-coded irq-enable of
  271. * _raw_spin_lock_flags() code, because lockdep assumes
  272. * that interrupts are not re-enabled during lock-acquire:
  273. */
  274. #ifdef CONFIG_PROVE_SPIN_LOCKING
  275. _raw_spin_lock(lock);
  276. #else
  277. _raw_spin_lock_flags(lock, &flags);
  278. #endif
  279. return flags;
  280. }
  281. EXPORT_SYMBOL(_spin_lock_irqsave_nested);
  282. #endif
  283. void __lockfunc _spin_unlock(spinlock_t *lock)
  284. {
  285. spin_release(&lock->dep_map, 1, _RET_IP_);
  286. _raw_spin_unlock(lock);
  287. preempt_enable();
  288. }
  289. EXPORT_SYMBOL(_spin_unlock);
  290. void __lockfunc _write_unlock(rwlock_t *lock)
  291. {
  292. rwlock_release(&lock->dep_map, 1, _RET_IP_);
  293. _raw_write_unlock(lock);
  294. preempt_enable();
  295. }
  296. EXPORT_SYMBOL(_write_unlock);
  297. void __lockfunc _read_unlock(rwlock_t *lock)
  298. {
  299. rwlock_release(&lock->dep_map, 1, _RET_IP_);
  300. _raw_read_unlock(lock);
  301. preempt_enable();
  302. }
  303. EXPORT_SYMBOL(_read_unlock);
  304. void __lockfunc _spin_unlock_irqrestore(spinlock_t *lock, unsigned long flags)
  305. {
  306. spin_release(&lock->dep_map, 1, _RET_IP_);
  307. _raw_spin_unlock(lock);
  308. local_irq_restore(flags);
  309. preempt_enable();
  310. }
  311. EXPORT_SYMBOL(_spin_unlock_irqrestore);
  312. void __lockfunc _spin_unlock_irq(spinlock_t *lock)
  313. {
  314. spin_release(&lock->dep_map, 1, _RET_IP_);
  315. _raw_spin_unlock(lock);
  316. local_irq_enable();
  317. preempt_enable();
  318. }
  319. EXPORT_SYMBOL(_spin_unlock_irq);
  320. void __lockfunc _spin_unlock_bh(spinlock_t *lock)
  321. {
  322. spin_release(&lock->dep_map, 1, _RET_IP_);
  323. _raw_spin_unlock(lock);
  324. preempt_enable_no_resched();
  325. local_bh_enable_ip((unsigned long)__builtin_return_address(0));
  326. }
  327. EXPORT_SYMBOL(_spin_unlock_bh);
  328. void __lockfunc _read_unlock_irqrestore(rwlock_t *lock, unsigned long flags)
  329. {
  330. rwlock_release(&lock->dep_map, 1, _RET_IP_);
  331. _raw_read_unlock(lock);
  332. local_irq_restore(flags);
  333. preempt_enable();
  334. }
  335. EXPORT_SYMBOL(_read_unlock_irqrestore);
  336. void __lockfunc _read_unlock_irq(rwlock_t *lock)
  337. {
  338. rwlock_release(&lock->dep_map, 1, _RET_IP_);
  339. _raw_read_unlock(lock);
  340. local_irq_enable();
  341. preempt_enable();
  342. }
  343. EXPORT_SYMBOL(_read_unlock_irq);
  344. void __lockfunc _read_unlock_bh(rwlock_t *lock)
  345. {
  346. rwlock_release(&lock->dep_map, 1, _RET_IP_);
  347. _raw_read_unlock(lock);
  348. preempt_enable_no_resched();
  349. local_bh_enable_ip((unsigned long)__builtin_return_address(0));
  350. }
  351. EXPORT_SYMBOL(_read_unlock_bh);
  352. void __lockfunc _write_unlock_irqrestore(rwlock_t *lock, unsigned long flags)
  353. {
  354. rwlock_release(&lock->dep_map, 1, _RET_IP_);
  355. _raw_write_unlock(lock);
  356. local_irq_restore(flags);
  357. preempt_enable();
  358. }
  359. EXPORT_SYMBOL(_write_unlock_irqrestore);
  360. void __lockfunc _write_unlock_irq(rwlock_t *lock)
  361. {
  362. rwlock_release(&lock->dep_map, 1, _RET_IP_);
  363. _raw_write_unlock(lock);
  364. local_irq_enable();
  365. preempt_enable();
  366. }
  367. EXPORT_SYMBOL(_write_unlock_irq);
  368. void __lockfunc _write_unlock_bh(rwlock_t *lock)
  369. {
  370. rwlock_release(&lock->dep_map, 1, _RET_IP_);
  371. _raw_write_unlock(lock);
  372. preempt_enable_no_resched();
  373. local_bh_enable_ip((unsigned long)__builtin_return_address(0));
  374. }
  375. EXPORT_SYMBOL(_write_unlock_bh);
  376. int __lockfunc _spin_trylock_bh(spinlock_t *lock)
  377. {
  378. local_bh_disable();
  379. preempt_disable();
  380. if (_raw_spin_trylock(lock)) {
  381. spin_acquire(&lock->dep_map, 0, 1, _RET_IP_);
  382. return 1;
  383. }
  384. preempt_enable_no_resched();
  385. local_bh_enable_ip((unsigned long)__builtin_return_address(0));
  386. return 0;
  387. }
  388. EXPORT_SYMBOL(_spin_trylock_bh);
  389. int in_lock_functions(unsigned long addr)
  390. {
  391. /* Linker adds these: start and end of __lockfunc functions */
  392. extern char __lock_text_start[], __lock_text_end[];
  393. return addr >= (unsigned long)__lock_text_start
  394. && addr < (unsigned long)__lock_text_end;
  395. }
  396. EXPORT_SYMBOL(in_lock_functions);