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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
1da177e4 LT |
2 | #ifndef __LINUX_SPINLOCK_H |
3 | #define __LINUX_SPINLOCK_H | |
4 | ||
5 | /* | |
fb1c8f93 IM |
6 | * include/linux/spinlock.h - generic spinlock/rwlock declarations |
7 | * | |
8 | * here's the role of the various spinlock/rwlock related include files: | |
9 | * | |
10 | * on SMP builds: | |
11 | * | |
fb3a6bbc | 12 | * asm/spinlock_types.h: contains the arch_spinlock_t/arch_rwlock_t and the |
fb1c8f93 IM |
13 | * initializers |
14 | * | |
15 | * linux/spinlock_types.h: | |
16 | * defines the generic type and initializers | |
17 | * | |
0199c4e6 | 18 | * asm/spinlock.h: contains the arch_spin_*()/etc. lowlevel |
fb1c8f93 IM |
19 | * implementations, mostly inline assembly code |
20 | * | |
21 | * (also included on UP-debug builds:) | |
22 | * | |
23 | * linux/spinlock_api_smp.h: | |
24 | * contains the prototypes for the _spin_*() APIs. | |
25 | * | |
26 | * linux/spinlock.h: builds the final spin_*() APIs. | |
27 | * | |
28 | * on UP builds: | |
29 | * | |
30 | * linux/spinlock_type_up.h: | |
31 | * contains the generic, simplified UP spinlock type. | |
32 | * (which is an empty structure on non-debug builds) | |
33 | * | |
34 | * linux/spinlock_types.h: | |
35 | * defines the generic type and initializers | |
36 | * | |
37 | * linux/spinlock_up.h: | |
0199c4e6 | 38 | * contains the arch_spin_*()/etc. version of UP |
fb1c8f93 IM |
39 | * builds. (which are NOPs on non-debug, non-preempt |
40 | * builds) | |
41 | * | |
42 | * (included on UP-non-debug builds:) | |
43 | * | |
44 | * linux/spinlock_api_up.h: | |
45 | * builds the _spin_*() APIs. | |
46 | * | |
47 | * linux/spinlock.h: builds the final spin_*() APIs. | |
1da177e4 LT |
48 | */ |
49 | ||
3f307891 | 50 | #include <linux/typecheck.h> |
1da177e4 LT |
51 | #include <linux/preempt.h> |
52 | #include <linux/linkage.h> | |
53 | #include <linux/compiler.h> | |
df9ee292 | 54 | #include <linux/irqflags.h> |
1da177e4 LT |
55 | #include <linux/thread_info.h> |
56 | #include <linux/kernel.h> | |
57 | #include <linux/stringify.h> | |
676dcb8b | 58 | #include <linux/bottom_half.h> |
96f951ed | 59 | #include <asm/barrier.h> |
1da177e4 | 60 | |
1da177e4 LT |
61 | |
62 | /* | |
63 | * Must define these before including other files, inline functions need them | |
64 | */ | |
75ddb0e8 | 65 | #define LOCK_SECTION_NAME ".text..lock."KBUILD_BASENAME |
1da177e4 LT |
66 | |
67 | #define LOCK_SECTION_START(extra) \ | |
68 | ".subsection 1\n\t" \ | |
69 | extra \ | |
70 | ".ifndef " LOCK_SECTION_NAME "\n\t" \ | |
71 | LOCK_SECTION_NAME ":\n\t" \ | |
72 | ".endif\n" | |
73 | ||
74 | #define LOCK_SECTION_END \ | |
75 | ".previous\n\t" | |
76 | ||
ec701584 | 77 | #define __lockfunc __attribute__((section(".spinlock.text"))) |
1da177e4 LT |
78 | |
79 | /* | |
fb3a6bbc | 80 | * Pull the arch_spinlock_t and arch_rwlock_t definitions: |
1da177e4 | 81 | */ |
fb1c8f93 | 82 | #include <linux/spinlock_types.h> |
1da177e4 | 83 | |
1da177e4 | 84 | /* |
25985edc | 85 | * Pull the arch_spin*() functions/declarations (UP-nondebug doesn't need them): |
1da177e4 | 86 | */ |
8a25d5de | 87 | #ifdef CONFIG_SMP |
fb1c8f93 | 88 | # include <asm/spinlock.h> |
1da177e4 | 89 | #else |
fb1c8f93 | 90 | # include <linux/spinlock_up.h> |
1da177e4 LT |
91 | #endif |
92 | ||
8a25d5de | 93 | #ifdef CONFIG_DEBUG_SPINLOCK |
c2f21ce2 TG |
94 | extern void __raw_spin_lock_init(raw_spinlock_t *lock, const char *name, |
95 | struct lock_class_key *key); | |
96 | # define raw_spin_lock_init(lock) \ | |
8a25d5de IM |
97 | do { \ |
98 | static struct lock_class_key __key; \ | |
99 | \ | |
c2f21ce2 | 100 | __raw_spin_lock_init((lock), #lock, &__key); \ |
8a25d5de IM |
101 | } while (0) |
102 | ||
103 | #else | |
c2f21ce2 TG |
104 | # define raw_spin_lock_init(lock) \ |
105 | do { *(lock) = __RAW_SPIN_LOCK_UNLOCKED(lock); } while (0) | |
8a25d5de IM |
106 | #endif |
107 | ||
c2f21ce2 | 108 | #define raw_spin_is_locked(lock) arch_spin_is_locked(&(lock)->raw_lock) |
fb1c8f93 | 109 | |
95c354fe | 110 | #ifdef CONFIG_GENERIC_LOCKBREAK |
c2f21ce2 | 111 | #define raw_spin_is_contended(lock) ((lock)->break_lock) |
95c354fe | 112 | #else |
a5ef7ca0 | 113 | |
0199c4e6 | 114 | #ifdef arch_spin_is_contended |
c2f21ce2 | 115 | #define raw_spin_is_contended(lock) arch_spin_is_contended(&(lock)->raw_lock) |
a5ef7ca0 | 116 | #else |
c2f21ce2 | 117 | #define raw_spin_is_contended(lock) (((void)(lock), 0)) |
0199c4e6 | 118 | #endif /*arch_spin_is_contended*/ |
95c354fe NP |
119 | #endif |
120 | ||
e0acd0a6 | 121 | /* |
d89e588c PZ |
122 | * This barrier must provide two things: |
123 | * | |
124 | * - it must guarantee a STORE before the spin_lock() is ordered against a | |
125 | * LOAD after it, see the comments at its two usage sites. | |
126 | * | |
127 | * - it must ensure the critical section is RCsc. | |
128 | * | |
129 | * The latter is important for cases where we observe values written by other | |
130 | * CPUs in spin-loops, without barriers, while being subject to scheduling. | |
131 | * | |
132 | * CPU0 CPU1 CPU2 | |
133 | * | |
134 | * for (;;) { | |
135 | * if (READ_ONCE(X)) | |
136 | * break; | |
137 | * } | |
138 | * X=1 | |
139 | * <sched-out> | |
140 | * <sched-in> | |
141 | * r = X; | |
142 | * | |
143 | * without transitivity it could be that CPU1 observes X!=0 breaks the loop, | |
144 | * we get migrated and CPU2 sees X==0. | |
145 | * | |
146 | * Since most load-store architectures implement ACQUIRE with an smp_mb() after | |
147 | * the LL/SC loop, they need no further barriers. Similarly all our TSO | |
148 | * architectures imply an smp_mb() for each atomic instruction and equally don't | |
149 | * need more. | |
150 | * | |
151 | * Architectures that can implement ACQUIRE better need to take care. | |
e0acd0a6 | 152 | */ |
d89e588c PZ |
153 | #ifndef smp_mb__after_spinlock |
154 | #define smp_mb__after_spinlock() do { } while (0) | |
ad462769 JO |
155 | #endif |
156 | ||
fb1c8f93 | 157 | #ifdef CONFIG_DEBUG_SPINLOCK |
b97c4bc1 | 158 | extern void do_raw_spin_lock(raw_spinlock_t *lock) __acquires(lock); |
9828ea9d TG |
159 | #define do_raw_spin_lock_flags(lock, flags) do_raw_spin_lock(lock) |
160 | extern int do_raw_spin_trylock(raw_spinlock_t *lock); | |
b97c4bc1 | 161 | extern void do_raw_spin_unlock(raw_spinlock_t *lock) __releases(lock); |
fb1c8f93 | 162 | #else |
b97c4bc1 | 163 | static inline void do_raw_spin_lock(raw_spinlock_t *lock) __acquires(lock) |
c2f21ce2 | 164 | { |
b97c4bc1 | 165 | __acquire(lock); |
c2f21ce2 TG |
166 | arch_spin_lock(&lock->raw_lock); |
167 | } | |
168 | ||
169 | static inline void | |
b97c4bc1 | 170 | do_raw_spin_lock_flags(raw_spinlock_t *lock, unsigned long *flags) __acquires(lock) |
c2f21ce2 | 171 | { |
b97c4bc1 | 172 | __acquire(lock); |
c2f21ce2 TG |
173 | arch_spin_lock_flags(&lock->raw_lock, *flags); |
174 | } | |
175 | ||
9828ea9d | 176 | static inline int do_raw_spin_trylock(raw_spinlock_t *lock) |
c2f21ce2 TG |
177 | { |
178 | return arch_spin_trylock(&(lock)->raw_lock); | |
179 | } | |
180 | ||
b97c4bc1 | 181 | static inline void do_raw_spin_unlock(raw_spinlock_t *lock) __releases(lock) |
c2f21ce2 TG |
182 | { |
183 | arch_spin_unlock(&lock->raw_lock); | |
b97c4bc1 | 184 | __release(lock); |
c2f21ce2 | 185 | } |
fb1c8f93 | 186 | #endif |
1da177e4 | 187 | |
1da177e4 | 188 | /* |
ef12f109 TG |
189 | * Define the various spin_lock methods. Note we define these |
190 | * regardless of whether CONFIG_SMP or CONFIG_PREEMPT are set. The | |
191 | * various methods are defined as nops in the case they are not | |
192 | * required. | |
1da177e4 | 193 | */ |
9c1721aa | 194 | #define raw_spin_trylock(lock) __cond_lock(lock, _raw_spin_trylock(lock)) |
1da177e4 | 195 | |
9c1721aa | 196 | #define raw_spin_lock(lock) _raw_spin_lock(lock) |
8a25d5de IM |
197 | |
198 | #ifdef CONFIG_DEBUG_LOCK_ALLOC | |
9c1721aa TG |
199 | # define raw_spin_lock_nested(lock, subclass) \ |
200 | _raw_spin_lock_nested(lock, subclass) | |
201 | ||
c2f21ce2 | 202 | # define raw_spin_lock_nest_lock(lock, nest_lock) \ |
b7d39aff PZ |
203 | do { \ |
204 | typecheck(struct lockdep_map *, &(nest_lock)->dep_map);\ | |
9c1721aa | 205 | _raw_spin_lock_nest_lock(lock, &(nest_lock)->dep_map); \ |
b7d39aff | 206 | } while (0) |
8a25d5de | 207 | #else |
4999201a BVA |
208 | /* |
209 | * Always evaluate the 'subclass' argument to avoid that the compiler | |
210 | * warns about set-but-not-used variables when building with | |
211 | * CONFIG_DEBUG_LOCK_ALLOC=n and with W=1. | |
212 | */ | |
213 | # define raw_spin_lock_nested(lock, subclass) \ | |
214 | _raw_spin_lock(((void)(subclass), (lock))) | |
9c1721aa | 215 | # define raw_spin_lock_nest_lock(lock, nest_lock) _raw_spin_lock(lock) |
8a25d5de IM |
216 | #endif |
217 | ||
fb1c8f93 | 218 | #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) |
b8e6ec86 | 219 | |
c2f21ce2 | 220 | #define raw_spin_lock_irqsave(lock, flags) \ |
3f307891 SR |
221 | do { \ |
222 | typecheck(unsigned long, flags); \ | |
9c1721aa | 223 | flags = _raw_spin_lock_irqsave(lock); \ |
3f307891 | 224 | } while (0) |
cfd3ef23 AV |
225 | |
226 | #ifdef CONFIG_DEBUG_LOCK_ALLOC | |
c2f21ce2 | 227 | #define raw_spin_lock_irqsave_nested(lock, flags, subclass) \ |
3f307891 SR |
228 | do { \ |
229 | typecheck(unsigned long, flags); \ | |
9c1721aa | 230 | flags = _raw_spin_lock_irqsave_nested(lock, subclass); \ |
3f307891 | 231 | } while (0) |
cfd3ef23 | 232 | #else |
c2f21ce2 | 233 | #define raw_spin_lock_irqsave_nested(lock, flags, subclass) \ |
3f307891 SR |
234 | do { \ |
235 | typecheck(unsigned long, flags); \ | |
9c1721aa | 236 | flags = _raw_spin_lock_irqsave(lock); \ |
3f307891 | 237 | } while (0) |
cfd3ef23 AV |
238 | #endif |
239 | ||
1da177e4 | 240 | #else |
b8e6ec86 | 241 | |
c2f21ce2 | 242 | #define raw_spin_lock_irqsave(lock, flags) \ |
3f307891 SR |
243 | do { \ |
244 | typecheck(unsigned long, flags); \ | |
9c1721aa | 245 | _raw_spin_lock_irqsave(lock, flags); \ |
3f307891 | 246 | } while (0) |
ef12f109 | 247 | |
c2f21ce2 TG |
248 | #define raw_spin_lock_irqsave_nested(lock, flags, subclass) \ |
249 | raw_spin_lock_irqsave(lock, flags) | |
cfd3ef23 | 250 | |
1da177e4 LT |
251 | #endif |
252 | ||
9c1721aa TG |
253 | #define raw_spin_lock_irq(lock) _raw_spin_lock_irq(lock) |
254 | #define raw_spin_lock_bh(lock) _raw_spin_lock_bh(lock) | |
255 | #define raw_spin_unlock(lock) _raw_spin_unlock(lock) | |
256 | #define raw_spin_unlock_irq(lock) _raw_spin_unlock_irq(lock) | |
1da177e4 | 257 | |
c2f21ce2 TG |
258 | #define raw_spin_unlock_irqrestore(lock, flags) \ |
259 | do { \ | |
260 | typecheck(unsigned long, flags); \ | |
9c1721aa | 261 | _raw_spin_unlock_irqrestore(lock, flags); \ |
3f307891 | 262 | } while (0) |
9c1721aa | 263 | #define raw_spin_unlock_bh(lock) _raw_spin_unlock_bh(lock) |
1da177e4 | 264 | |
9c1721aa TG |
265 | #define raw_spin_trylock_bh(lock) \ |
266 | __cond_lock(lock, _raw_spin_trylock_bh(lock)) | |
1da177e4 | 267 | |
c2f21ce2 | 268 | #define raw_spin_trylock_irq(lock) \ |
1da177e4 LT |
269 | ({ \ |
270 | local_irq_disable(); \ | |
c2f21ce2 | 271 | raw_spin_trylock(lock) ? \ |
fb1c8f93 | 272 | 1 : ({ local_irq_enable(); 0; }); \ |
1da177e4 LT |
273 | }) |
274 | ||
c2f21ce2 | 275 | #define raw_spin_trylock_irqsave(lock, flags) \ |
1da177e4 LT |
276 | ({ \ |
277 | local_irq_save(flags); \ | |
c2f21ce2 | 278 | raw_spin_trylock(lock) ? \ |
fb1c8f93 | 279 | 1 : ({ local_irq_restore(flags); 0; }); \ |
1da177e4 LT |
280 | }) |
281 | ||
c2f21ce2 TG |
282 | /** |
283 | * raw_spin_can_lock - would raw_spin_trylock() succeed? | |
284 | * @lock: the spinlock in question. | |
285 | */ | |
286 | #define raw_spin_can_lock(lock) (!raw_spin_is_locked(lock)) | |
287 | ||
288 | /* Include rwlock functions */ | |
289 | #include <linux/rwlock.h> | |
290 | ||
291 | /* | |
292 | * Pull the _spin_*()/_read_*()/_write_*() functions/declarations: | |
293 | */ | |
294 | #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) | |
295 | # include <linux/spinlock_api_smp.h> | |
296 | #else | |
297 | # include <linux/spinlock_api_up.h> | |
298 | #endif | |
299 | ||
300 | /* | |
301 | * Map the spin_lock functions to the raw variants for PREEMPT_RT=n | |
302 | */ | |
303 | ||
3490565b | 304 | static __always_inline raw_spinlock_t *spinlock_check(spinlock_t *lock) |
c2f21ce2 TG |
305 | { |
306 | return &lock->rlock; | |
307 | } | |
308 | ||
309 | #define spin_lock_init(_lock) \ | |
310 | do { \ | |
311 | spinlock_check(_lock); \ | |
312 | raw_spin_lock_init(&(_lock)->rlock); \ | |
313 | } while (0) | |
314 | ||
3490565b | 315 | static __always_inline void spin_lock(spinlock_t *lock) |
c2f21ce2 TG |
316 | { |
317 | raw_spin_lock(&lock->rlock); | |
318 | } | |
319 | ||
3490565b | 320 | static __always_inline void spin_lock_bh(spinlock_t *lock) |
c2f21ce2 TG |
321 | { |
322 | raw_spin_lock_bh(&lock->rlock); | |
323 | } | |
324 | ||
3490565b | 325 | static __always_inline int spin_trylock(spinlock_t *lock) |
c2f21ce2 TG |
326 | { |
327 | return raw_spin_trylock(&lock->rlock); | |
328 | } | |
329 | ||
330 | #define spin_lock_nested(lock, subclass) \ | |
331 | do { \ | |
332 | raw_spin_lock_nested(spinlock_check(lock), subclass); \ | |
333 | } while (0) | |
334 | ||
335 | #define spin_lock_nest_lock(lock, nest_lock) \ | |
336 | do { \ | |
337 | raw_spin_lock_nest_lock(spinlock_check(lock), nest_lock); \ | |
338 | } while (0) | |
339 | ||
3490565b | 340 | static __always_inline void spin_lock_irq(spinlock_t *lock) |
c2f21ce2 TG |
341 | { |
342 | raw_spin_lock_irq(&lock->rlock); | |
343 | } | |
344 | ||
345 | #define spin_lock_irqsave(lock, flags) \ | |
346 | do { \ | |
347 | raw_spin_lock_irqsave(spinlock_check(lock), flags); \ | |
348 | } while (0) | |
349 | ||
350 | #define spin_lock_irqsave_nested(lock, flags, subclass) \ | |
351 | do { \ | |
352 | raw_spin_lock_irqsave_nested(spinlock_check(lock), flags, subclass); \ | |
353 | } while (0) | |
354 | ||
3490565b | 355 | static __always_inline void spin_unlock(spinlock_t *lock) |
c2f21ce2 TG |
356 | { |
357 | raw_spin_unlock(&lock->rlock); | |
358 | } | |
359 | ||
3490565b | 360 | static __always_inline void spin_unlock_bh(spinlock_t *lock) |
c2f21ce2 TG |
361 | { |
362 | raw_spin_unlock_bh(&lock->rlock); | |
363 | } | |
364 | ||
3490565b | 365 | static __always_inline void spin_unlock_irq(spinlock_t *lock) |
c2f21ce2 TG |
366 | { |
367 | raw_spin_unlock_irq(&lock->rlock); | |
368 | } | |
369 | ||
3490565b | 370 | static __always_inline void spin_unlock_irqrestore(spinlock_t *lock, unsigned long flags) |
c2f21ce2 TG |
371 | { |
372 | raw_spin_unlock_irqrestore(&lock->rlock, flags); | |
373 | } | |
374 | ||
3490565b | 375 | static __always_inline int spin_trylock_bh(spinlock_t *lock) |
c2f21ce2 TG |
376 | { |
377 | return raw_spin_trylock_bh(&lock->rlock); | |
378 | } | |
379 | ||
3490565b | 380 | static __always_inline int spin_trylock_irq(spinlock_t *lock) |
c2f21ce2 TG |
381 | { |
382 | return raw_spin_trylock_irq(&lock->rlock); | |
383 | } | |
384 | ||
385 | #define spin_trylock_irqsave(lock, flags) \ | |
386 | ({ \ | |
387 | raw_spin_trylock_irqsave(spinlock_check(lock), flags); \ | |
388 | }) | |
389 | ||
3490565b | 390 | static __always_inline int spin_is_locked(spinlock_t *lock) |
c2f21ce2 TG |
391 | { |
392 | return raw_spin_is_locked(&lock->rlock); | |
393 | } | |
394 | ||
3490565b | 395 | static __always_inline int spin_is_contended(spinlock_t *lock) |
c2f21ce2 TG |
396 | { |
397 | return raw_spin_is_contended(&lock->rlock); | |
398 | } | |
399 | ||
3490565b | 400 | static __always_inline int spin_can_lock(spinlock_t *lock) |
c2f21ce2 TG |
401 | { |
402 | return raw_spin_can_lock(&lock->rlock); | |
403 | } | |
404 | ||
4ebc1b4b | 405 | #define assert_spin_locked(lock) assert_raw_spin_locked(&(lock)->rlock) |
c2f21ce2 | 406 | |
1da177e4 | 407 | /* |
fb1c8f93 IM |
408 | * Pull the atomic_t declaration: |
409 | * (asm-mips/atomic.h needs above definitions) | |
1da177e4 | 410 | */ |
60063497 | 411 | #include <linux/atomic.h> |
fb1c8f93 IM |
412 | /** |
413 | * atomic_dec_and_lock - lock on reaching reference count zero | |
414 | * @atomic: the atomic counter | |
415 | * @lock: the spinlock in question | |
dc07e721 BF |
416 | * |
417 | * Decrements @atomic by 1. If the result is 0, returns true and locks | |
418 | * @lock. Returns false for all other cases. | |
1da177e4 | 419 | */ |
fb1c8f93 IM |
420 | extern int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock); |
421 | #define atomic_dec_and_lock(atomic, lock) \ | |
dcc8e559 | 422 | __cond_lock(lock, _atomic_dec_and_lock(atomic, lock)) |
1da177e4 | 423 | |
1da177e4 | 424 | #endif /* __LINUX_SPINLOCK_H */ |