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 /*
  26  * If lockdep is enabled then we use the non-preemption spin-ops
  27  * even on CONFIG_PREEMPT, because lockdep assumes that interrupts are
  28  * not re-enabled during lock-acquire (which the preempt-spin-ops do):
  29  */
  30 #if !defined(CONFIG_GENERIC_LOCKBREAK) || defined(CONFIG_DEBUG_LOCK_ALLOC)
  31 /*
  32  * The __lock_function inlines are taken from
  33  * spinlock : include/linux/spinlock_api_smp.h
  34  * rwlock   : include/linux/rwlock_api_smp.h
  35  */
  36 #else
  37
  38 /*
  39  * Some architectures can relax in favour of the CPU owning the lock.
  40  */
  41 #ifndef arch_read_relax
  42 # define arch_read_relax(l)     cpu_relax()
  43 #endif
  44 #ifndef arch_write_relax
  45 # define arch_write_relax(l)    cpu_relax()
  46 #endif
  47 #ifndef arch_spin_relax
  48 # define arch_spin_relax(l)     cpu_relax()
  49 #endif
  50
  51 /*
  52  * We build the __lock_function inlines here. They are too large for
  53  * inlining all over the place, but here is only one user per function
  54  * which embedds them into the calling _lock_function below.
  55  *
  56  * This could be a long-held lock. We both prepare to spin for a long
  57  * time (making _this_ CPU preemptable if possible), and we also signal
  58  * towards that other CPU that it should break the lock ASAP.
  59  */
  60 #define BUILD_LOCK_OPS(op, locktype)                                    \
  61 void __lockfunc __raw_##op##_lock(locktype##_t *lock)                   \
  62 {                                                                       \
  63         for (;;) {                                                      \
  64                 preempt_disable();                                      \
  65                 if (likely(do_raw_##op##_trylock(lock)))                \
  66                         break;                                          \
  67                 preempt_enable();                                       \
  68                                                                         \
  69                 arch_##op##_relax(&lock->raw_lock);                     \
  70         }                                                               \
  71 }                                                                       \
  72                                                                         \
  73 unsigned long __lockfunc __raw_##op##_lock_irqsave(locktype##_t *lock)  \
  74 {                                                                       \
  75         unsigned long flags;                                            \
  76                                                                         \
  77         for (;;) {                                                      \
  78                 preempt_disable();                                      \
  79                 local_irq_save(flags);                                  \
  80                 if (likely(do_raw_##op##_trylock(lock)))                \
  81                         break;                                          \
  82                 local_irq_restore(flags);                               \
  83                 preempt_enable();                                       \
  84                                                                         \
  85                 arch_##op##_relax(&lock->raw_lock);                     \
  86         }                                                               \
  87                                                                         \
  88         return flags;                                                   \
  89 }                                                                       \
  90                                                                         \
  91 void __lockfunc __raw_##op##_lock_irq(locktype##_t *lock)               \
  92 {                                                                       \
  93         _raw_##op##_lock_irqsave(lock);                                 \
  94 }                                                                       \
  95                                                                         \
  96 void __lockfunc __raw_##op##_lock_bh(locktype##_t *lock)                \
  97 {                                                                       \
  98         unsigned long flags;                                            \
  99                                                                         \
 100         /*                                                      */      \
 101         /* Careful: we must exclude softirqs too, hence the     */      \
 102         /* irq-disabling. We use the generic preemption-aware   */      \
 103         /* function:                                            */      \
 104         /**/                                                            \
 105         flags = _raw_##op##_lock_irqsave(lock);                         \
 106         local_bh_disable();                                             \
 107         local_irq_restore(flags);                                       \
 108 }                                                                       \
 109
 110 /*
 111  * Build preemption-friendly versions of the following
 112  * lock-spinning functions:
 113  *
 114  *         __[spin|read|write]_lock()
 115  *         __[spin|read|write]_lock_irq()
 116  *         __[spin|read|write]_lock_irqsave()
 117  *         __[spin|read|write]_lock_bh()
 118  */
 119 BUILD_LOCK_OPS(spin, raw_spinlock);
 120 BUILD_LOCK_OPS(read, rwlock);
 121 BUILD_LOCK_OPS(write, rwlock);
 122
 123 #endif
 124
 125 #ifndef CONFIG_INLINE_SPIN_TRYLOCK
 126 int __lockfunc _raw_spin_trylock(raw_spinlock_t *lock)
 127 {
 128         return __raw_spin_trylock(lock);
 129 }
 130 EXPORT_SYMBOL(_raw_spin_trylock);
 131 #endif
 132
 133 #ifndef CONFIG_INLINE_SPIN_TRYLOCK_BH
 134 int __lockfunc _raw_spin_trylock_bh(raw_spinlock_t *lock)
 135 {
 136         return __raw_spin_trylock_bh(lock);
 137 }
 138 EXPORT_SYMBOL(_raw_spin_trylock_bh);
 139 #endif
 140
 141 #ifndef CONFIG_INLINE_SPIN_LOCK
 142 void __lockfunc _raw_spin_lock(raw_spinlock_t *lock)
 143 {
 144         __raw_spin_lock(lock);
 145 }
 146 EXPORT_SYMBOL(_raw_spin_lock);
 147 #endif
 148
 149 #ifndef CONFIG_INLINE_SPIN_LOCK_IRQSAVE
 150 unsigned long __lockfunc _raw_spin_lock_irqsave(raw_spinlock_t *lock)
 151 {
 152         return __raw_spin_lock_irqsave(lock);
 153 }
 154 EXPORT_SYMBOL(_raw_spin_lock_irqsave);
 155 #endif
 156
 157 #ifndef CONFIG_INLINE_SPIN_LOCK_IRQ
 158 void __lockfunc _raw_spin_lock_irq(raw_spinlock_t *lock)
 159 {
 160         __raw_spin_lock_irq(lock);
 161 }
 162 EXPORT_SYMBOL(_raw_spin_lock_irq);
 163 #endif
 164
 165 #ifndef CONFIG_INLINE_SPIN_LOCK_BH
 166 void __lockfunc _raw_spin_lock_bh(raw_spinlock_t *lock)
 167 {
 168         __raw_spin_lock_bh(lock);
 169 }
 170 EXPORT_SYMBOL(_raw_spin_lock_bh);
 171 #endif
 172
 173 #ifdef CONFIG_UNINLINE_SPIN_UNLOCK
 174 void __lockfunc _raw_spin_unlock(raw_spinlock_t *lock)
 175 {
 176         __raw_spin_unlock(lock);
 177 }
 178 EXPORT_SYMBOL(_raw_spin_unlock);
 179 #endif
 180
 181 #ifndef CONFIG_INLINE_SPIN_UNLOCK_IRQRESTORE
 182 void __lockfunc _raw_spin_unlock_irqrestore(raw_spinlock_t *lock, unsigned long flags)
 183 {
 184         __raw_spin_unlock_irqrestore(lock, flags);
 185 }
 186 EXPORT_SYMBOL(_raw_spin_unlock_irqrestore);
 187 #endif
 188
 189 #ifndef CONFIG_INLINE_SPIN_UNLOCK_IRQ
 190 void __lockfunc _raw_spin_unlock_irq(raw_spinlock_t *lock)
 191 {
 192         __raw_spin_unlock_irq(lock);
 193 }
 194 EXPORT_SYMBOL(_raw_spin_unlock_irq);
 195 #endif
 196
 197 #ifndef CONFIG_INLINE_SPIN_UNLOCK_BH
 198 void __lockfunc _raw_spin_unlock_bh(raw_spinlock_t *lock)
 199 {
 200         __raw_spin_unlock_bh(lock);
 201 }
 202 EXPORT_SYMBOL(_raw_spin_unlock_bh);
 203 #endif
 204
 205 #ifndef CONFIG_INLINE_READ_TRYLOCK
 206 int __lockfunc _raw_read_trylock(rwlock_t *lock)
 207 {
 208         return __raw_read_trylock(lock);
 209 }
 210 EXPORT_SYMBOL(_raw_read_trylock);
 211 #endif
 212
 213 #ifndef CONFIG_INLINE_READ_LOCK
 214 void __lockfunc _raw_read_lock(rwlock_t *lock)
 215 {
 216         __raw_read_lock(lock);
 217 }
 218 EXPORT_SYMBOL(_raw_read_lock);
 219 #endif
 220
 221 #ifndef CONFIG_INLINE_READ_LOCK_IRQSAVE
 222 unsigned long __lockfunc _raw_read_lock_irqsave(rwlock_t *lock)
 223 {
 224         return __raw_read_lock_irqsave(lock);
 225 }
 226 EXPORT_SYMBOL(_raw_read_lock_irqsave);
 227 #endif
 228
 229 #ifndef CONFIG_INLINE_READ_LOCK_IRQ
 230 void __lockfunc _raw_read_lock_irq(rwlock_t *lock)
 231 {
 232         __raw_read_lock_irq(lock);
 233 }
 234 EXPORT_SYMBOL(_raw_read_lock_irq);
 235 #endif
 236
 237 #ifndef CONFIG_INLINE_READ_LOCK_BH
 238 void __lockfunc _raw_read_lock_bh(rwlock_t *lock)
 239 {
 240         __raw_read_lock_bh(lock);
 241 }
 242 EXPORT_SYMBOL(_raw_read_lock_bh);
 243 #endif
 244
 245 #ifndef CONFIG_INLINE_READ_UNLOCK
 246 void __lockfunc _raw_read_unlock(rwlock_t *lock)
 247 {
 248         __raw_read_unlock(lock);
 249 }
 250 EXPORT_SYMBOL(_raw_read_unlock);
 251 #endif
 252
 253 #ifndef CONFIG_INLINE_READ_UNLOCK_IRQRESTORE
 254 void __lockfunc _raw_read_unlock_irqrestore(rwlock_t *lock, unsigned long flags)
 255 {
 256         __raw_read_unlock_irqrestore(lock, flags);
 257 }
 258 EXPORT_SYMBOL(_raw_read_unlock_irqrestore);
 259 #endif
 260
 261 #ifndef CONFIG_INLINE_READ_UNLOCK_IRQ
 262 void __lockfunc _raw_read_unlock_irq(rwlock_t *lock)
 263 {
 264         __raw_read_unlock_irq(lock);
 265 }
 266 EXPORT_SYMBOL(_raw_read_unlock_irq);
 267 #endif
 268
 269 #ifndef CONFIG_INLINE_READ_UNLOCK_BH
 270 void __lockfunc _raw_read_unlock_bh(rwlock_t *lock)
 271 {
 272         __raw_read_unlock_bh(lock);
 273 }
 274 EXPORT_SYMBOL(_raw_read_unlock_bh);
 275 #endif
 276
 277 #ifndef CONFIG_INLINE_WRITE_TRYLOCK
 278 int __lockfunc _raw_write_trylock(rwlock_t *lock)
 279 {
 280         return __raw_write_trylock(lock);
 281 }
 282 EXPORT_SYMBOL(_raw_write_trylock);
 283 #endif
 284
 285 #ifndef CONFIG_INLINE_WRITE_LOCK
 286 void __lockfunc _raw_write_lock(rwlock_t *lock)
 287 {
 288         __raw_write_lock(lock);
 289 }
 290 EXPORT_SYMBOL(_raw_write_lock);
 291 #endif
 292
 293 #ifndef CONFIG_INLINE_WRITE_LOCK_IRQSAVE
 294 unsigned long __lockfunc _raw_write_lock_irqsave(rwlock_t *lock)
 295 {
 296         return __raw_write_lock_irqsave(lock);
 297 }
 298 EXPORT_SYMBOL(_raw_write_lock_irqsave);
 299 #endif
 300
 301 #ifndef CONFIG_INLINE_WRITE_LOCK_IRQ
 302 void __lockfunc _raw_write_lock_irq(rwlock_t *lock)
 303 {
 304         __raw_write_lock_irq(lock);
 305 }
 306 EXPORT_SYMBOL(_raw_write_lock_irq);
 307 #endif
 308
 309 #ifndef CONFIG_INLINE_WRITE_LOCK_BH
 310 void __lockfunc _raw_write_lock_bh(rwlock_t *lock)
 311 {
 312         __raw_write_lock_bh(lock);
 313 }
 314 EXPORT_SYMBOL(_raw_write_lock_bh);
 315 #endif
 316
 317 #ifndef CONFIG_INLINE_WRITE_UNLOCK
 318 void __lockfunc _raw_write_unlock(rwlock_t *lock)
 319 {
 320         __raw_write_unlock(lock);
 321 }
 322 EXPORT_SYMBOL(_raw_write_unlock);
 323 #endif
 324
 325 #ifndef CONFIG_INLINE_WRITE_UNLOCK_IRQRESTORE
 326 void __lockfunc _raw_write_unlock_irqrestore(rwlock_t *lock, unsigned long flags)
 327 {
 328         __raw_write_unlock_irqrestore(lock, flags);
 329 }
 330 EXPORT_SYMBOL(_raw_write_unlock_irqrestore);
 331 #endif
 332
 333 #ifndef CONFIG_INLINE_WRITE_UNLOCK_IRQ
 334 void __lockfunc _raw_write_unlock_irq(rwlock_t *lock)
 335 {
 336         __raw_write_unlock_irq(lock);
 337 }
 338 EXPORT_SYMBOL(_raw_write_unlock_irq);
 339 #endif
 340
 341 #ifndef CONFIG_INLINE_WRITE_UNLOCK_BH
 342 void __lockfunc _raw_write_unlock_bh(rwlock_t *lock)
 343 {
 344         __raw_write_unlock_bh(lock);
 345 }
 346 EXPORT_SYMBOL(_raw_write_unlock_bh);
 347 #endif
 348
 349 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 350
 351 void __lockfunc _raw_spin_lock_nested(raw_spinlock_t *lock, int subclass)
 352 {
 353         preempt_disable();
 354         spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
 355         LOCK_CONTENDED(lock, do_raw_spin_trylock, do_raw_spin_lock);
 356 }
 357 EXPORT_SYMBOL(_raw_spin_lock_nested);
 358
 359 unsigned long __lockfunc _raw_spin_lock_irqsave_nested(raw_spinlock_t *lock,
 360                                                    int subclass)
 361 {
 362         unsigned long flags;
 363
 364         local_irq_save(flags);
 365         preempt_disable();
 366         spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
 367         LOCK_CONTENDED_FLAGS(lock, do_raw_spin_trylock, do_raw_spin_lock,
 368                                 do_raw_spin_lock_flags, &flags);
 369         return flags;
 370 }
 371 EXPORT_SYMBOL(_raw_spin_lock_irqsave_nested);
 372
 373 void __lockfunc _raw_spin_lock_nest_lock(raw_spinlock_t *lock,
 374                                      struct lockdep_map *nest_lock)
 375 {
 376         preempt_disable();
 377         spin_acquire_nest(&lock->dep_map, 0, 0, nest_lock, _RET_IP_);
 378         LOCK_CONTENDED(lock, do_raw_spin_trylock, do_raw_spin_lock);
 379 }
 380 EXPORT_SYMBOL(_raw_spin_lock_nest_lock);
 381
 382 #endif
 383
 384 notrace int in_lock_functions(unsigned long addr)
 385 {
 386         /* Linker adds these: start and end of __lockfunc functions */
 387         extern char __lock_text_start[], __lock_text_end[];
 388
 389         return addr >= (unsigned long)__lock_text_start
 390         && addr < (unsigned long)__lock_text_end;
 391 }
 392 EXPORT_SYMBOL(in_lock_functions);