1#ifndef __LINUX_SPINLOCK_H 2#define __LINUX_SPINLOCK_H 3 4/* 5 * include/linux/spinlock.h - generic spinlock/rwlock declarations 6 * 7 * here's the role of the various spinlock/rwlock related include files: 8 * 9 * on SMP builds: 10 * 11 * asm/spinlock_types.h: contains the arch_spinlock_t/arch_rwlock_t and the 12 * initializers 13 * 14 * linux/spinlock_types.h: 15 * defines the generic type and initializers 16 * 17 * asm/spinlock.h: contains the arch_spin_*()/etc. lowlevel 18 * implementations, mostly inline assembly code 19 * 20 * (also included on UP-debug builds:) 21 * 22 * linux/spinlock_api_smp.h: 23 * contains the prototypes for the _spin_*() APIs. 24 * 25 * linux/spinlock.h: builds the final spin_*() APIs. 26 * 27 * on UP builds: 28 * 29 * linux/spinlock_type_up.h: 30 * contains the generic, simplified UP spinlock type. 31 * (which is an empty structure on non-debug builds) 32 * 33 * linux/spinlock_types.h: 34 * defines the generic type and initializers 35 * 36 * linux/spinlock_up.h: 37 * contains the arch_spin_*()/etc. version of UP 38 * builds. (which are NOPs on non-debug, non-preempt 39 * builds) 40 * 41 * (included on UP-non-debug builds:) 42 * 43 * linux/spinlock_api_up.h: 44 * builds the _spin_*() APIs. 45 * 46 * linux/spinlock.h: builds the final spin_*() APIs. 47 */ 48 49#include <linux/typecheck.h> 50#include <linux/preempt.h> 51#include <linux/linkage.h> 52#include <linux/compiler.h> 53#include <linux/irqflags.h> 54#include <linux/thread_info.h> 55#include <linux/kernel.h> 56#include <linux/stringify.h> 57#include <linux/bottom_half.h> 58#include <asm/barrier.h> 59 60 61/* 62 * Must define these before including other files, inline functions need them 63 */ 64#define LOCK_SECTION_NAME ".text..lock."KBUILD_BASENAME 65 66#define LOCK_SECTION_START(extra) \ 67 ".subsection 1\n\t" \ 68 extra \ 69 ".ifndef " LOCK_SECTION_NAME "\n\t" \ 70 LOCK_SECTION_NAME ":\n\t" \ 71 ".endif\n" 72 73#define LOCK_SECTION_END \ 74 ".previous\n\t" 75 76#define __lockfunc __attribute__((section(".spinlock.text"))) 77 78/* 79 * Pull the arch_spinlock_t and arch_rwlock_t definitions: 80 */ 81#include <linux/spinlock_types.h> 82 83/* 84 * Pull the arch_spin*() functions/declarations (UP-nondebug doesn't need them): 85 */ 86#ifdef CONFIG_SMP 87# include <asm/spinlock.h> 88#else 89# include <linux/spinlock_up.h> 90#endif 91 92#ifdef CONFIG_DEBUG_SPINLOCK 93 extern void __raw_spin_lock_init(raw_spinlock_t *lock, const char *name, 94 struct lock_class_key *key); 95# define raw_spin_lock_init(lock) \ 96do { \ 97 static struct lock_class_key __key; \ 98 \ 99 __raw_spin_lock_init((lock), #lock, &__key); \ 100} while (0) 101 102#else 103# define raw_spin_lock_init(lock) \ 104 do { *(lock) = __RAW_SPIN_LOCK_UNLOCKED(lock); } while (0) 105#endif 106 107#define raw_spin_is_locked(lock) arch_spin_is_locked(&(lock)->raw_lock) 108 109#ifdef CONFIG_GENERIC_LOCKBREAK 110#define raw_spin_is_contended(lock) ((lock)->break_lock) 111#else 112 113#ifdef arch_spin_is_contended 114#define raw_spin_is_contended(lock) arch_spin_is_contended(&(lock)->raw_lock) 115#else 116#define raw_spin_is_contended(lock) (((void)(lock), 0)) 117#endif /*arch_spin_is_contended*/ 118#endif 119 120/* 121 * Despite its name it doesn't necessarily has to be a full barrier. 122 * It should only guarantee that a STORE before the critical section 123 * can not be reordered with a LOAD inside this section. 124 * spin_lock() is the one-way barrier, this LOAD can not escape out 125 * of the region. So the default implementation simply ensures that 126 * a STORE can not move into the critical section, smp_wmb() should 127 * serialize it with another STORE done by spin_lock(). 128 */ 129#ifndef smp_mb__before_spinlock 130#define smp_mb__before_spinlock() smp_wmb() 131#endif 132 133/* 134 * Place this after a lock-acquisition primitive to guarantee that 135 * an UNLOCK+LOCK pair act as a full barrier. This guarantee applies 136 * if the UNLOCK and LOCK are executed by the same CPU or if the 137 * UNLOCK and LOCK operate on the same lock variable. 138 */ 139#ifndef smp_mb__after_unlock_lock 140#define smp_mb__after_unlock_lock() do { } while (0) 141#endif 142 143/** 144 * raw_spin_unlock_wait - wait until the spinlock gets unlocked 145 * @lock: the spinlock in question. 146 */ 147#define raw_spin_unlock_wait(lock) arch_spin_unlock_wait(&(lock)->raw_lock) 148 149#ifdef CONFIG_DEBUG_SPINLOCK 150 extern void do_raw_spin_lock(raw_spinlock_t *lock) __acquires(lock); 151#define do_raw_spin_lock_flags(lock, flags) do_raw_spin_lock(lock) 152 extern int do_raw_spin_trylock(raw_spinlock_t *lock); 153 extern void do_raw_spin_unlock(raw_spinlock_t *lock) __releases(lock); 154#else 155static inline void do_raw_spin_lock(raw_spinlock_t *lock) __acquires(lock) 156{ 157 __acquire(lock); 158 arch_spin_lock(&lock->raw_lock); 159} 160 161static inline void 162do_raw_spin_lock_flags(raw_spinlock_t *lock, unsigned long *flags) __acquires(lock) 163{ 164 __acquire(lock); 165 arch_spin_lock_flags(&lock->raw_lock, *flags); 166} 167 168static inline int do_raw_spin_trylock(raw_spinlock_t *lock) 169{ 170 return arch_spin_trylock(&(lock)->raw_lock); 171} 172 173static inline void do_raw_spin_unlock(raw_spinlock_t *lock) __releases(lock) 174{ 175 arch_spin_unlock(&lock->raw_lock); 176 __release(lock); 177} 178#endif 179 180/* 181 * Define the various spin_lock methods. Note we define these 182 * regardless of whether CONFIG_SMP or CONFIG_PREEMPT are set. The 183 * various methods are defined as nops in the case they are not 184 * required. 185 */ 186#define raw_spin_trylock(lock) __cond_lock(lock, _raw_spin_trylock(lock)) 187 188#define raw_spin_lock(lock) _raw_spin_lock(lock) 189 190#ifdef CONFIG_DEBUG_LOCK_ALLOC 191# define raw_spin_lock_nested(lock, subclass) \ 192 _raw_spin_lock_nested(lock, subclass) 193# define raw_spin_lock_bh_nested(lock, subclass) \ 194 _raw_spin_lock_bh_nested(lock, subclass) 195 196# define raw_spin_lock_nest_lock(lock, nest_lock) \ 197 do { \ 198 typecheck(struct lockdep_map *, &(nest_lock)->dep_map);\ 199 _raw_spin_lock_nest_lock(lock, &(nest_lock)->dep_map); \ 200 } while (0) 201#else 202/* 203 * Always evaluate the 'subclass' argument to avoid that the compiler 204 * warns about set-but-not-used variables when building with 205 * CONFIG_DEBUG_LOCK_ALLOC=n and with W=1. 206 */ 207# define raw_spin_lock_nested(lock, subclass) \ 208 _raw_spin_lock(((void)(subclass), (lock))) 209# define raw_spin_lock_nest_lock(lock, nest_lock) _raw_spin_lock(lock) 210# define raw_spin_lock_bh_nested(lock, subclass) _raw_spin_lock_bh(lock) 211#endif 212 213#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) 214 215#define raw_spin_lock_irqsave(lock, flags) \ 216 do { \ 217 typecheck(unsigned long, flags); \ 218 flags = _raw_spin_lock_irqsave(lock); \ 219 } while (0) 220 221#ifdef CONFIG_DEBUG_LOCK_ALLOC 222#define raw_spin_lock_irqsave_nested(lock, flags, subclass) \ 223 do { \ 224 typecheck(unsigned long, flags); \ 225 flags = _raw_spin_lock_irqsave_nested(lock, subclass); \ 226 } while (0) 227#else 228#define raw_spin_lock_irqsave_nested(lock, flags, subclass) \ 229 do { \ 230 typecheck(unsigned long, flags); \ 231 flags = _raw_spin_lock_irqsave(lock); \ 232 } while (0) 233#endif 234 235#else 236 237#define raw_spin_lock_irqsave(lock, flags) \ 238 do { \ 239 typecheck(unsigned long, flags); \ 240 _raw_spin_lock_irqsave(lock, flags); \ 241 } while (0) 242 243#define raw_spin_lock_irqsave_nested(lock, flags, subclass) \ 244 raw_spin_lock_irqsave(lock, flags) 245 246#endif 247 248#define raw_spin_lock_irq(lock) _raw_spin_lock_irq(lock) 249#define raw_spin_lock_bh(lock) _raw_spin_lock_bh(lock) 250#define raw_spin_unlock(lock) _raw_spin_unlock(lock) 251#define raw_spin_unlock_irq(lock) _raw_spin_unlock_irq(lock) 252 253#define raw_spin_unlock_irqrestore(lock, flags) \ 254 do { \ 255 typecheck(unsigned long, flags); \ 256 _raw_spin_unlock_irqrestore(lock, flags); \ 257 } while (0) 258#define raw_spin_unlock_bh(lock) _raw_spin_unlock_bh(lock) 259 260#define raw_spin_trylock_bh(lock) \ 261 __cond_lock(lock, _raw_spin_trylock_bh(lock)) 262 263#define raw_spin_trylock_irq(lock) \ 264({ \ 265 local_irq_disable(); \ 266 raw_spin_trylock(lock) ? \ 267 1 : ({ local_irq_enable(); 0; }); \ 268}) 269 270#define raw_spin_trylock_irqsave(lock, flags) \ 271({ \ 272 local_irq_save(flags); \ 273 raw_spin_trylock(lock) ? \ 274 1 : ({ local_irq_restore(flags); 0; }); \ 275}) 276 277/** 278 * raw_spin_can_lock - would raw_spin_trylock() succeed? 279 * @lock: the spinlock in question. 280 */ 281#define raw_spin_can_lock(lock) (!raw_spin_is_locked(lock)) 282 283/* Include rwlock functions */ 284#include <linux/rwlock.h> 285 286/* 287 * Pull the _spin_*()/_read_*()/_write_*() functions/declarations: 288 */ 289#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) 290# include <linux/spinlock_api_smp.h> 291#else 292# include <linux/spinlock_api_up.h> 293#endif 294 295/* 296 * Map the spin_lock functions to the raw variants for PREEMPT_RT=n 297 */ 298 299static inline raw_spinlock_t *spinlock_check(spinlock_t *lock) 300{ 301 return &lock->rlock; 302} 303 304#define spin_lock_init(_lock) \ 305do { \ 306 spinlock_check(_lock); \ 307 raw_spin_lock_init(&(_lock)->rlock); \ 308} while (0) 309 310static inline void spin_lock(spinlock_t *lock) 311{ 312 raw_spin_lock(&lock->rlock); 313} 314 315static inline void spin_lock_bh(spinlock_t *lock) 316{ 317 raw_spin_lock_bh(&lock->rlock); 318} 319 320static inline int spin_trylock(spinlock_t *lock) 321{ 322 return raw_spin_trylock(&lock->rlock); 323} 324 325#define spin_lock_nested(lock, subclass) \ 326do { \ 327 raw_spin_lock_nested(spinlock_check(lock), subclass); \ 328} while (0) 329 330#define spin_lock_bh_nested(lock, subclass) \ 331do { \ 332 raw_spin_lock_bh_nested(spinlock_check(lock), subclass);\ 333} while (0) 334 335#define spin_lock_nest_lock(lock, nest_lock) \ 336do { \ 337 raw_spin_lock_nest_lock(spinlock_check(lock), nest_lock); \ 338} while (0) 339 340static inline void spin_lock_irq(spinlock_t *lock) 341{ 342 raw_spin_lock_irq(&lock->rlock); 343} 344 345#define spin_lock_irqsave(lock, flags) \ 346do { \ 347 raw_spin_lock_irqsave(spinlock_check(lock), flags); \ 348} while (0) 349 350#define spin_lock_irqsave_nested(lock, flags, subclass) \ 351do { \ 352 raw_spin_lock_irqsave_nested(spinlock_check(lock), flags, subclass); \ 353} while (0) 354 355static inline void spin_unlock(spinlock_t *lock) 356{ 357 raw_spin_unlock(&lock->rlock); 358} 359 360static inline void spin_unlock_bh(spinlock_t *lock) 361{ 362 raw_spin_unlock_bh(&lock->rlock); 363} 364 365static inline void spin_unlock_irq(spinlock_t *lock) 366{ 367 raw_spin_unlock_irq(&lock->rlock); 368} 369 370static inline void spin_unlock_irqrestore(spinlock_t *lock, unsigned long flags) 371{ 372 raw_spin_unlock_irqrestore(&lock->rlock, flags); 373} 374 375static inline int spin_trylock_bh(spinlock_t *lock) 376{ 377 return raw_spin_trylock_bh(&lock->rlock); 378} 379 380static inline int spin_trylock_irq(spinlock_t *lock) 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 390static inline void spin_unlock_wait(spinlock_t *lock) 391{ 392 raw_spin_unlock_wait(&lock->rlock); 393} 394 395static inline int spin_is_locked(spinlock_t *lock) 396{ 397 return raw_spin_is_locked(&lock->rlock); 398} 399 400static inline int spin_is_contended(spinlock_t *lock) 401{ 402 return raw_spin_is_contended(&lock->rlock); 403} 404 405static inline int spin_can_lock(spinlock_t *lock) 406{ 407 return raw_spin_can_lock(&lock->rlock); 408} 409 410#define assert_spin_locked(lock) assert_raw_spin_locked(&(lock)->rlock) 411 412/* 413 * Pull the atomic_t declaration: 414 * (asm-mips/atomic.h needs above definitions) 415 */ 416#include <linux/atomic.h> 417/** 418 * atomic_dec_and_lock - lock on reaching reference count zero 419 * @atomic: the atomic counter 420 * @lock: the spinlock in question 421 * 422 * Decrements @atomic by 1. If the result is 0, returns true and locks 423 * @lock. Returns false for all other cases. 424 */ 425extern int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock); 426#define atomic_dec_and_lock(atomic, lock) \ 427 __cond_lock(lock, _atomic_dec_and_lock(atomic, lock)) 428 429#endif /* __LINUX_SPINLOCK_H */ 430