kernel/kernel/locking/spinlock.c

   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
  17 #include <linux/linkage.h>
  18 #include <linux/preempt.h>
  19 #include <linux/spinlock.h>
  20 #include <linux/interrupt.h>
  21 #include <linux/debug_locks.h>
  22 #include <linux/export.h>
  23
  24 /*
  25  * If lockdep is enabled then we use the non-preemption spin-ops
  26  * even on CONFIG_PREEMPT, because lockdep assumes that interrupts are
  27  * not re-enabled during lock-acquire (which the preempt-spin-ops do):
  28  */
  29 #if !defined(CONFIG_GENERIC_LOCKBREAK) || defined(CONFIG_DEBUG_LOCK_ALLOC)
  30 /*
  31  * The __lock_function inlines are taken from
  32  * include/linux/spinlock_api_smp.h
  33  */
  34 #else
  35 #define raw_read_can_lock(l)    read_can_lock(l)
  36 #define raw_write_can_lock(l)   write_can_lock(l)
  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                 if (!(lock)->break_lock)                                \
  70                         (lock)->break_lock = 1;                         \
  71                 while (!raw_##op##_can_lock(lock) && (lock)->break_lock)\
  72                         arch_##op##_relax(&lock->raw_lock);             \
  73         }                                                               \
  74         (lock)->break_lock = 0;                                         \
  75 }                                                                       \
  76                                                                         \
  77 unsigned long __lockfunc __raw_##op##_lock_irqsave(locktype##_t *lock)  \
  78 {                                                                       \
  79         unsigned long flags;                                            \
  80                                                                         \
  81         for (;;) {                                                      \
  82                 preempt_disable();                                      \
  83                 local_irq_save(flags);                                  \
  84                 if (likely(do_raw_##op##_trylock(lock)))                \
  85                         break;                                          \
  86                 local_irq_restore(flags);                               \
  87                 preempt_enable();                                       \
  88                                                                         \
  89                 if (!(lock)->break_lock)                                \
  90                         (lock)->break_lock = 1;                         \
  91                 while (!raw_##op##_can_lock(lock) && (lock)->break_lock)\
  92                         arch_##op##_relax(&lock->raw_lock);             \
  93         }                                                               \
  94         (lock)->break_lock = 0;                                         \
  95         return flags;                                                   \
  96 }                                                                       \
  97                                                                         \
  98 void __lockfunc __raw_##op##_lock_irq(locktype##_t *lock)               \
  99 {                                                                       \
 100         _raw_##op##_lock_irqsave(lock);                                 \
 101 }                                                                       \
 102                                                                         \
 103 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_FULL
 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 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 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 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 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 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 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 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 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 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 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_FULL
 216
 217 #ifndef CONFIG_INLINE_READ_TRYLOCK
 218 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 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 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 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 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 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 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 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 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 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 void __lockfunc _raw_write_lock(rwlock_t *lock)
 299 {
 300         __raw_write_lock(lock);
 301 }
 302 EXPORT_SYMBOL(_raw_write_lock);
 303 #endif
 304
 305 #ifndef CONFIG_INLINE_WRITE_LOCK_IRQSAVE
 306 unsigned long __lockfunc _raw_write_lock_irqsave(rwlock_t *lock)
 307 {
 308         return __raw_write_lock_irqsave(lock);
 309 }
 310 EXPORT_SYMBOL(_raw_write_lock_irqsave);
 311 #endif
 312
 313 #ifndef CONFIG_INLINE_WRITE_LOCK_IRQ
 314 void __lockfunc _raw_write_lock_irq(rwlock_t *lock)
 315 {
 316         __raw_write_lock_irq(lock);
 317 }
 318 EXPORT_SYMBOL(_raw_write_lock_irq);
 319 #endif
 320
 321 #ifndef CONFIG_INLINE_WRITE_LOCK_BH
 322 void __lockfunc _raw_write_lock_bh(rwlock_t *lock)
 323 {
 324         __raw_write_lock_bh(lock);
 325 }
 326 EXPORT_SYMBOL(_raw_write_lock_bh);
 327 #endif
 328
 329 #ifndef CONFIG_INLINE_WRITE_UNLOCK
 330 void __lockfunc _raw_write_unlock(rwlock_t *lock)
 331 {
 332         __raw_write_unlock(lock);
 333 }
 334 EXPORT_SYMBOL(_raw_write_unlock);
 335 #endif
 336
 337 #ifndef CONFIG_INLINE_WRITE_UNLOCK_IRQRESTORE
 338 void __lockfunc _raw_write_unlock_irqrestore(rwlock_t *lock, unsigned long flags)
 339 {
 340         __raw_write_unlock_irqrestore(lock, flags);
 341 }
 342 EXPORT_SYMBOL(_raw_write_unlock_irqrestore);
 343 #endif
 344
 345 #ifndef CONFIG_INLINE_WRITE_UNLOCK_IRQ
 346 void __lockfunc _raw_write_unlock_irq(rwlock_t *lock)
 347 {
 348         __raw_write_unlock_irq(lock);
 349 }
 350 EXPORT_SYMBOL(_raw_write_unlock_irq);
 351 #endif
 352
 353 #ifndef CONFIG_INLINE_WRITE_UNLOCK_BH
 354 void __lockfunc _raw_write_unlock_bh(rwlock_t *lock)
 355 {
 356         __raw_write_unlock_bh(lock);
 357 }
 358 EXPORT_SYMBOL(_raw_write_unlock_bh);
 359 #endif
 360
 361 #endif /* !PREEMPT_RT_FULL */
 362
 363 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 364
 365 void __lockfunc _raw_spin_lock_nested(raw_spinlock_t *lock, int subclass)
 366 {
 367         preempt_disable();
 368         spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
 369         LOCK_CONTENDED(lock, do_raw_spin_trylock, do_raw_spin_lock);
 370 }
 371 EXPORT_SYMBOL(_raw_spin_lock_nested);
 372
 373 void __lockfunc _raw_spin_lock_bh_nested(raw_spinlock_t *lock, int subclass)
 374 {
 375         __local_bh_disable_ip(_RET_IP_, SOFTIRQ_LOCK_OFFSET);
 376         spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
 377         LOCK_CONTENDED(lock, do_raw_spin_trylock, do_raw_spin_lock);
 378 }
 379 EXPORT_SYMBOL(_raw_spin_lock_bh_nested);
 380
 381 unsigned long __lockfunc _raw_spin_lock_irqsave_nested(raw_spinlock_t *lock,
 382                                                    int subclass)
 383 {
 384         unsigned long flags;
 385
 386         local_irq_save(flags);
 387         preempt_disable();
 388         spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
 389         LOCK_CONTENDED_FLAGS(lock, do_raw_spin_trylock, do_raw_spin_lock,
 390                                 do_raw_spin_lock_flags, &flags);
 391         return flags;
 392 }
 393 EXPORT_SYMBOL(_raw_spin_lock_irqsave_nested);
 394
 395 void __lockfunc _raw_spin_lock_nest_lock(raw_spinlock_t *lock,
 396                                      struct lockdep_map *nest_lock)
 397 {
 398         preempt_disable();
 399         spin_acquire_nest(&lock->dep_map, 0, 0, nest_lock, _RET_IP_);
 400         LOCK_CONTENDED(lock, do_raw_spin_trylock, do_raw_spin_lock);
 401 }
 402 EXPORT_SYMBOL(_raw_spin_lock_nest_lock);
 403
 404 #endif
 405
 406 notrace int in_lock_functions(unsigned long addr)
 407 {
 408         /* Linker adds these: start and end of __lockfunc functions */
 409         extern char __lock_text_start[], __lock_text_end[];
 410
 411         return addr >= (unsigned long)__lock_text_start
 412         && addr < (unsigned long)__lock_text_end;
 413 }
 414 EXPORT_SYMBOL(in_lock_functions);