mutex.h revision 167387
1/*- 2 * Copyright (c) 1997 Berkeley Software Design, Inc. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 3. Berkeley Software Design Inc's name may not be used to endorse or 13 * promote products derived from this software without specific prior 14 * written permission. 15 * 16 * THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN INC ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL BERKELEY SOFTWARE DESIGN INC BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 * 28 * from BSDI $Id: mutex.h,v 2.7.2.35 2000/04/27 03:10:26 cp Exp $ 29 * $FreeBSD: head/sys/sys/mutex.h 167387 2007-03-09 22:41:01Z jhb $ 30 */ 31 32#ifndef _SYS_MUTEX_H_ 33#define _SYS_MUTEX_H_ 34 35#ifndef LOCORE 36#include <sys/queue.h> 37#include <sys/_lock.h> 38#include <sys/_mutex.h> 39 40#ifdef _KERNEL 41#include <sys/pcpu.h> 42#include <sys/lock_profile.h> 43#include <machine/atomic.h> 44#include <machine/cpufunc.h> 45#endif /* _KERNEL_ */ 46#endif /* !LOCORE */ 47 48#include <machine/mutex.h> 49 50#ifdef _KERNEL 51 52/* 53 * Mutex types and options passed to mtx_init(). MTX_QUIET and MTX_DUPOK 54 * can also be passed in. 55 */ 56#define MTX_DEF 0x00000000 /* DEFAULT (sleep) lock */ 57#define MTX_SPIN 0x00000001 /* Spin lock (disables interrupts) */ 58#define MTX_RECURSE 0x00000004 /* Option: lock allowed to recurse */ 59#define MTX_NOWITNESS 0x00000008 /* Don't do any witness checking. */ 60#define MTX_NOPROFILE 0x00000020 /* Don't profile this lock */ 61 62/* 63 * Option flags passed to certain lock/unlock routines, through the use 64 * of corresponding mtx_{lock,unlock}_flags() interface macros. 65 */ 66#define MTX_QUIET LOP_QUIET /* Don't log a mutex event */ 67#define MTX_DUPOK LOP_DUPOK /* Don't log a duplicate acquire */ 68 69/* 70 * State bits kept in mutex->mtx_lock, for the DEFAULT lock type. None of this, 71 * with the exception of MTX_UNOWNED, applies to spin locks. 72 */ 73#define MTX_RECURSED 0x00000001 /* lock recursed (for MTX_DEF only) */ 74#define MTX_CONTESTED 0x00000002 /* lock contested (for MTX_DEF only) */ 75#define MTX_UNOWNED 0x00000004 /* Cookie for free mutex */ 76#define MTX_FLAGMASK (MTX_RECURSED | MTX_CONTESTED | MTX_UNOWNED) 77 78/* 79 * Value stored in mutex->mtx_lock to denote a destroyed mutex. 80 */ 81#define MTX_DESTROYED (MTX_CONTESTED | MTX_UNOWNED) 82 83#endif /* _KERNEL */ 84 85#ifndef LOCORE 86 87/* 88 * XXX: Friendly reminder to fix things in MP code that is presently being 89 * XXX: worked on. 90 */ 91#define mp_fixme(string) 92 93#ifdef _KERNEL 94 95/* 96 * Prototypes 97 * 98 * NOTE: Functions prepended with `_' (underscore) are exported to other parts 99 * of the kernel via macros, thus allowing us to use the cpp LOCK_FILE 100 * and LOCK_LINE. These functions should not be called directly by any 101 * code using the API. Their macros cover their functionality. 102 * 103 * [See below for descriptions] 104 * 105 */ 106void mtx_init(struct mtx *m, const char *name, const char *type, int opts); 107void mtx_destroy(struct mtx *m); 108void mtx_sysinit(void *arg); 109void mutex_init(void); 110void _mtx_lock_sleep(struct mtx *m, uintptr_t tid, int opts, 111 const char *file, int line); 112void _mtx_unlock_sleep(struct mtx *m, int opts, const char *file, int line); 113#ifdef SMP 114void _mtx_lock_spin(struct mtx *m, uintptr_t tid, int opts, 115 const char *file, int line); 116#endif 117void _mtx_unlock_spin(struct mtx *m, int opts, const char *file, int line); 118int _mtx_trylock(struct mtx *m, int opts, const char *file, int line); 119void _mtx_lock_flags(struct mtx *m, int opts, const char *file, int line); 120void _mtx_unlock_flags(struct mtx *m, int opts, const char *file, int line); 121void _mtx_lock_spin_flags(struct mtx *m, int opts, const char *file, 122 int line); 123void _mtx_unlock_spin_flags(struct mtx *m, int opts, const char *file, 124 int line); 125#if defined(INVARIANTS) || defined(INVARIANT_SUPPORT) 126void _mtx_assert(struct mtx *m, int what, const char *file, int line); 127#endif 128 129/* 130 * We define our machine-independent (unoptimized) mutex micro-operations 131 * here, if they are not already defined in the machine-dependent mutex.h 132 */ 133 134/* Try to obtain mtx_lock once. */ 135#ifndef _obtain_lock 136#define _obtain_lock(mp, tid) \ 137 atomic_cmpset_acq_ptr(&(mp)->mtx_lock, MTX_UNOWNED, (tid)) 138#endif 139 140/* Try to release mtx_lock if it is unrecursed and uncontested. */ 141#ifndef _release_lock 142#define _release_lock(mp, tid) \ 143 atomic_cmpset_rel_ptr(&(mp)->mtx_lock, (tid), MTX_UNOWNED) 144#endif 145 146/* Release mtx_lock quickly, assuming we own it. */ 147#ifndef _release_lock_quick 148#define _release_lock_quick(mp) \ 149 atomic_store_rel_ptr(&(mp)->mtx_lock, MTX_UNOWNED) 150#endif 151 152/* 153 * Obtain a sleep lock inline, or call the "hard" function if we can't get it 154 * easy. 155 */ 156#ifndef _get_sleep_lock 157#define _get_sleep_lock(mp, tid, opts, file, line) do { \ 158 uintptr_t _tid = (uintptr_t)(tid); \ 159 int contested = 0; \ 160 uint64_t waittime = 0; \ 161 if (!_obtain_lock((mp), _tid)) { \ 162 lock_profile_obtain_lock_failed(&(mp)->mtx_object, \ 163 &contested, &waittime); \ 164 _mtx_lock_sleep((mp), _tid, (opts), (file), (line)); \ 165 } \ 166 lock_profile_obtain_lock_success(&(mp)->mtx_object, contested, \ 167 waittime, (file), (line)); \ 168} while (0) 169#endif 170 171/* 172 * Obtain a spin lock inline, or call the "hard" function if we can't get it 173 * easy. For spinlocks, we handle recursion inline (it turns out that function 174 * calls can be significantly expensive on some architectures). 175 * Since spin locks are not _too_ common, inlining this code is not too big 176 * a deal. 177 */ 178#ifndef _get_spin_lock 179#ifdef SMP 180#define _get_spin_lock(mp, tid, opts, file, line) do { \ 181 uintptr_t _tid = (uintptr_t)(tid); \ 182 int contested = 0; \ 183 uint64_t waittime = 0; \ 184 spinlock_enter(); \ 185 if (!_obtain_lock((mp), _tid)) { \ 186 if ((mp)->mtx_lock == _tid) \ 187 (mp)->mtx_recurse++; \ 188 else { \ 189 lock_profile_obtain_lock_failed(&(mp)->mtx_object, \ 190 &contested, &waittime); \ 191 _mtx_lock_spin((mp), _tid, (opts), (file), (line)); \ 192 } \ 193 } \ 194 lock_profile_obtain_lock_success(&(mp)->mtx_object, contested, \ 195 waittime, (file), (line)); \ 196} while (0) 197#else /* SMP */ 198#define _get_spin_lock(mp, tid, opts, file, line) do { \ 199 uintptr_t _tid = (uintptr_t)(tid); \ 200 \ 201 spinlock_enter(); \ 202 if ((mp)->mtx_lock == _tid) \ 203 (mp)->mtx_recurse++; \ 204 else { \ 205 KASSERT((mp)->mtx_lock == MTX_UNOWNED, ("corrupt spinlock")); \ 206 (mp)->mtx_lock = _tid; \ 207 } \ 208} while (0) 209#endif /* SMP */ 210#endif 211 212/* 213 * Release a sleep lock inline, or call the "hard" function if we can't do it 214 * easy. 215 */ 216#ifndef _rel_sleep_lock 217#define _rel_sleep_lock(mp, tid, opts, file, line) do { \ 218 uintptr_t _tid = (uintptr_t)(tid); \ 219 \ 220 if (!_release_lock((mp), _tid)) \ 221 _mtx_unlock_sleep((mp), (opts), (file), (line)); \ 222} while (0) 223#endif 224 225/* 226 * For spinlocks, we can handle everything inline, as it's pretty simple and 227 * a function call would be too expensive (at least on some architectures). 228 * Since spin locks are not _too_ common, inlining this code is not too big 229 * a deal. 230 * 231 * Since we always perform a spinlock_enter() when attempting to acquire a 232 * spin lock, we need to always perform a matching spinlock_exit() when 233 * releasing a spin lock. This includes the recursion cases. 234 */ 235#ifndef _rel_spin_lock 236#ifdef SMP 237#define _rel_spin_lock(mp) do { \ 238 if (mtx_recursed((mp))) \ 239 (mp)->mtx_recurse--; \ 240 else \ 241 _release_lock_quick((mp)); \ 242 spinlock_exit(); \ 243} while (0) 244#else /* SMP */ 245#define _rel_spin_lock(mp) do { \ 246 if (mtx_recursed((mp))) \ 247 (mp)->mtx_recurse--; \ 248 else \ 249 (mp)->mtx_lock = MTX_UNOWNED; \ 250 spinlock_exit(); \ 251} while (0) 252#endif /* SMP */ 253#endif 254 255/* 256 * Exported lock manipulation interface. 257 * 258 * mtx_lock(m) locks MTX_DEF mutex `m' 259 * 260 * mtx_lock_spin(m) locks MTX_SPIN mutex `m' 261 * 262 * mtx_unlock(m) unlocks MTX_DEF mutex `m' 263 * 264 * mtx_unlock_spin(m) unlocks MTX_SPIN mutex `m' 265 * 266 * mtx_lock_spin_flags(m, opts) and mtx_lock_flags(m, opts) locks mutex `m' 267 * and passes option flags `opts' to the "hard" function, if required. 268 * With these routines, it is possible to pass flags such as MTX_QUIET 269 * to the appropriate lock manipulation routines. 270 * 271 * mtx_trylock(m) attempts to acquire MTX_DEF mutex `m' but doesn't sleep if 272 * it cannot. Rather, it returns 0 on failure and non-zero on success. 273 * It does NOT handle recursion as we assume that if a caller is properly 274 * using this part of the interface, he will know that the lock in question 275 * is _not_ recursed. 276 * 277 * mtx_trylock_flags(m, opts) is used the same way as mtx_trylock() but accepts 278 * relevant option flags `opts.' 279 * 280 * mtx_initialized(m) returns non-zero if the lock `m' has been initialized. 281 * 282 * mtx_owned(m) returns non-zero if the current thread owns the lock `m' 283 * 284 * mtx_recursed(m) returns non-zero if the lock `m' is presently recursed. 285 */ 286#define mtx_lock(m) mtx_lock_flags((m), 0) 287#define mtx_lock_spin(m) mtx_lock_spin_flags((m), 0) 288#define mtx_trylock(m) mtx_trylock_flags((m), 0) 289#define mtx_unlock(m) mtx_unlock_flags((m), 0) 290#define mtx_unlock_spin(m) mtx_unlock_spin_flags((m), 0) 291 292struct mtx_pool; 293 294struct mtx_pool *mtx_pool_create(const char *mtx_name, int pool_size, int opts); 295void mtx_pool_destroy(struct mtx_pool **poolp); 296struct mtx *mtx_pool_find(struct mtx_pool *pool, void *ptr); 297struct mtx *mtx_pool_alloc(struct mtx_pool *pool); 298#define mtx_pool_lock(pool, ptr) \ 299 mtx_lock(mtx_pool_find((pool), (ptr))) 300#define mtx_pool_lock_spin(pool, ptr) \ 301 mtx_lock_spin(mtx_pool_find((pool), (ptr))) 302#define mtx_pool_unlock(pool, ptr) \ 303 mtx_unlock(mtx_pool_find((pool), (ptr))) 304#define mtx_pool_unlock_spin(pool, ptr) \ 305 mtx_unlock_spin(mtx_pool_find((pool), (ptr))) 306 307/* 308 * mtxpool_lockbuilder is a pool of sleep locks that is not witness 309 * checked and should only be used for building higher level locks. 310 * 311 * mtxpool_sleep is a general purpose pool of sleep mutexes. 312 */ 313extern struct mtx_pool *mtxpool_lockbuilder; 314extern struct mtx_pool *mtxpool_sleep; 315 316#ifndef LOCK_DEBUG 317#error LOCK_DEBUG not defined, include <sys/lock.h> before <sys/mutex.h> 318#endif 319#if LOCK_DEBUG > 0 || defined(MUTEX_NOINLINE) 320#define mtx_lock_flags(m, opts) \ 321 _mtx_lock_flags((m), (opts), LOCK_FILE, LOCK_LINE) 322#define mtx_unlock_flags(m, opts) \ 323 _mtx_unlock_flags((m), (opts), LOCK_FILE, LOCK_LINE) 324#define mtx_lock_spin_flags(m, opts) \ 325 _mtx_lock_spin_flags((m), (opts), LOCK_FILE, LOCK_LINE) 326#define mtx_unlock_spin_flags(m, opts) \ 327 _mtx_unlock_spin_flags((m), (opts), LOCK_FILE, LOCK_LINE) 328#else /* LOCK_DEBUG == 0 && !MUTEX_NOINLINE */ 329#define mtx_lock_flags(m, opts) \ 330 _get_sleep_lock((m), curthread, (opts), LOCK_FILE, LOCK_LINE) 331#define mtx_unlock_flags(m, opts) \ 332 _rel_sleep_lock((m), curthread, (opts), LOCK_FILE, LOCK_LINE) 333#define mtx_lock_spin_flags(m, opts) \ 334 _get_spin_lock((m), curthread, (opts), LOCK_FILE, LOCK_LINE) 335#define mtx_unlock_spin_flags(m, opts) \ 336 _rel_spin_lock((m)) 337#endif /* LOCK_DEBUG > 0 || MUTEX_NOINLINE */ 338 339#define mtx_trylock_flags(m, opts) \ 340 _mtx_trylock((m), (opts), LOCK_FILE, LOCK_LINE) 341 342#define mtx_sleep(chan, mtx, pri, wmesg, timo) \ 343 _sleep((chan), &(mtx)->mtx_object, (pri), (wmesg), (timo)) 344 345#define mtx_initialized(m) lock_initalized(&(m)->mtx_object) 346 347#define mtx_owned(m) (((m)->mtx_lock & ~MTX_FLAGMASK) == (uintptr_t)curthread) 348 349#define mtx_recursed(m) ((m)->mtx_recurse != 0) 350 351#define mtx_name(m) ((m)->mtx_object.lo_name) 352 353/* 354 * Global locks. 355 */ 356extern struct mtx sched_lock; 357extern struct mtx Giant; 358 359/* 360 * Giant lock manipulation and clean exit macros. 361 * Used to replace return with an exit Giant and return. 362 * 363 * Note that DROP_GIANT*() needs to be paired with PICKUP_GIANT() 364 * The #ifndef is to allow lint-like tools to redefine DROP_GIANT. 365 */ 366#ifndef DROP_GIANT 367#define DROP_GIANT() \ 368do { \ 369 int _giantcnt; \ 370 WITNESS_SAVE_DECL(Giant); \ 371 \ 372 if (mtx_owned(&Giant)) \ 373 WITNESS_SAVE(&Giant.mtx_object, Giant); \ 374 for (_giantcnt = 0; mtx_owned(&Giant); _giantcnt++) \ 375 mtx_unlock(&Giant) 376 377#define PICKUP_GIANT() \ 378 mtx_assert(&Giant, MA_NOTOWNED); \ 379 while (_giantcnt--) \ 380 mtx_lock(&Giant); \ 381 if (mtx_owned(&Giant)) \ 382 WITNESS_RESTORE(&Giant.mtx_object, Giant); \ 383} while (0) 384 385#define PARTIAL_PICKUP_GIANT() \ 386 mtx_assert(&Giant, MA_NOTOWNED); \ 387 while (_giantcnt--) \ 388 mtx_lock(&Giant); \ 389 if (mtx_owned(&Giant)) \ 390 WITNESS_RESTORE(&Giant.mtx_object, Giant) 391#endif 392 393/* 394 * Network MPSAFE temporary workarounds. When debug_mpsafenet 395 * is 1 the network is assumed to operate without Giant on the 396 * input path and protocols that require Giant must collect it 397 * on entry. When 0 Giant is grabbed in the network interface 398 * ISR's and in the netisr path and there is no need to grab 399 * the Giant lock. Note that, unlike GIANT_PICKUP() and 400 * GIANT_DROP(), these macros directly wrap mutex operations 401 * without special recursion handling. 402 * 403 * This mechanism is intended as temporary until everything of 404 * importance is properly locked. Note: the semantics for 405 * NET_{LOCK,UNLOCK}_GIANT() are not the same as DROP_GIANT() 406 * and PICKUP_GIANT(), as they are plain mutex operations 407 * without a recursion counter. 408 */ 409extern int debug_mpsafenet; /* defined in net/netisr.c */ 410#define NET_LOCK_GIANT() do { \ 411 if (!debug_mpsafenet) \ 412 mtx_lock(&Giant); \ 413} while (0) 414#define NET_UNLOCK_GIANT() do { \ 415 if (!debug_mpsafenet) \ 416 mtx_unlock(&Giant); \ 417} while (0) 418#define NET_ASSERT_GIANT() do { \ 419 if (!debug_mpsafenet) \ 420 mtx_assert(&Giant, MA_OWNED); \ 421} while (0) 422#define NET_CALLOUT_MPSAFE (debug_mpsafenet ? CALLOUT_MPSAFE : 0) 423 424#define UGAR(rval) do { \ 425 int _val = (rval); \ 426 mtx_unlock(&Giant); \ 427 return (_val); \ 428} while (0) 429 430struct mtx_args { 431 struct mtx *ma_mtx; 432 const char *ma_desc; 433 int ma_opts; 434}; 435 436#define MTX_SYSINIT(name, mtx, desc, opts) \ 437 static struct mtx_args name##_args = { \ 438 (mtx), \ 439 (desc), \ 440 (opts) \ 441 }; \ 442 SYSINIT(name##_mtx_sysinit, SI_SUB_LOCK, SI_ORDER_MIDDLE, \ 443 mtx_sysinit, &name##_args); \ 444 SYSUNINIT(name##_mtx_sysuninit, SI_SUB_LOCK, SI_ORDER_MIDDLE, \ 445 mtx_destroy, (mtx)) 446 447/* 448 * The INVARIANTS-enabled mtx_assert() functionality. 449 * 450 * The constants need to be defined for INVARIANT_SUPPORT infrastructure 451 * support as _mtx_assert() itself uses them and the latter implies that 452 * _mtx_assert() must build. 453 */ 454#if defined(INVARIANTS) || defined(INVARIANT_SUPPORT) 455#define MA_OWNED 0x01 456#define MA_NOTOWNED 0x02 457#define MA_RECURSED 0x04 458#define MA_NOTRECURSED 0x08 459#endif 460 461#ifdef INVARIANTS 462#define mtx_assert(m, what) \ 463 _mtx_assert((m), (what), __FILE__, __LINE__) 464 465#define GIANT_REQUIRED mtx_assert(&Giant, MA_OWNED) 466 467#else /* INVARIANTS */ 468#define mtx_assert(m, what) 469#define GIANT_REQUIRED 470#endif /* INVARIANTS */ 471 472/* 473 * Common lock type names. 474 */ 475#define MTX_NETWORK_LOCK "network driver" 476 477#endif /* _KERNEL */ 478#endif /* !LOCORE */ 479#endif /* _SYS_MUTEX_H_ */ 480