kernel/locking/spinlock.c

   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 static 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 static 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 static void __lockfunc __raw_##op##_lock_irq(locktype##_t *lock)        \
  99 {                                                                       \
 100         _raw_##op##_lock_irqsave(lock);                                 \
 101 }                                                                       \
 102                                                                         \
 103 static 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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 417 #if defined(CONFIG_PROVE_LOCKING) && defined(CONFIG_PREEMPT_RT)
 418 void notrace lockdep_assert_in_softirq_func(void)
 419 {
 420         lockdep_assert_in_softirq();
 421 }
 422 EXPORT_SYMBOL(lockdep_assert_in_softirq_func);
 423 #endif