mutex.h revision 74900
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 74900 2001-03-28 02:40:47Z jhb $ 30 */ 31 32#ifndef _SYS_MUTEX_H_ 33#define _SYS_MUTEX_H_ 34 35#ifndef LOCORE 36#include <sys/queue.h> 37 38#ifdef _KERNEL 39#include <sys/ktr.h> 40#include <sys/systm.h> 41#include <machine/atomic.h> 42#include <machine/cpufunc.h> 43#include <machine/globals.h> 44#endif /* _KERNEL_ */ 45#endif /* !LOCORE */ 46 47#include <machine/mutex.h> 48 49#ifdef _KERNEL 50 51/* 52 * Mutex types and options stored in mutex->mtx_flags 53 */ 54#define MTX_DEF 0x00000000 /* DEFAULT (sleep) lock */ 55#define MTX_SPIN 0x00000001 /* Spin lock (disables interrupts) */ 56#define MTX_RECURSE 0x00000002 /* Option: lock allowed to recurse */ 57 58/* 59 * Option flags passed to certain lock/unlock routines, through the use 60 * of corresponding mtx_{lock,unlock}_flags() interface macros. 61 * 62 * XXX: The only reason we make these bits not interfere with the above "types 63 * and options" bits is because we have to pass both to the witness 64 * routines right now; if/when we clean up the witness interface to 65 * not check for mutex type from the passed in flag, but rather from 66 * the mutex lock's mtx_flags field, then we can change these values to 67 * 0x1, 0x2, ... 68 */ 69#define MTX_NOSWITCH 0x00000004 /* Do not switch on release */ 70#define MTX_QUIET 0x00000008 /* Don't log a mutex event */ 71 72/* 73 * State bits kept in mutex->mtx_lock, for the DEFAULT lock type. None of this, 74 * with the exception of MTX_UNOWNED, applies to spin locks. 75 */ 76#define MTX_RECURSED 0x00000001 /* lock recursed (for MTX_DEF only) */ 77#define MTX_CONTESTED 0x00000002 /* lock contested (for MTX_DEF only) */ 78#define MTX_UNOWNED 0x00000004 /* Cookie for free mutex */ 79#define MTX_FLAGMASK ~(MTX_RECURSED | MTX_CONTESTED) 80 81#endif /* _KERNEL */ 82 83#ifndef LOCORE 84 85struct mtx_debug; 86 87/* 88 * Sleep/spin mutex 89 */ 90struct mtx { 91 volatile uintptr_t mtx_lock; /* owner (and state for sleep locks) */ 92 volatile u_int mtx_recurse; /* number of recursive holds */ 93 u_int mtx_savecrit; /* saved flags (for spin locks) */ 94 int mtx_flags; /* flags passed to mtx_init() */ 95 const char *mtx_description; 96 TAILQ_HEAD(, proc) mtx_blocked; /* threads blocked on this lock */ 97 LIST_ENTRY(mtx) mtx_contested; /* list of all contested locks */ 98 struct mtx *mtx_next; /* all existing locks */ 99 struct mtx *mtx_prev; /* in system... */ 100 struct mtx_debug *mtx_debug; /* debugging information... */ 101}; 102 103/* 104 * XXX: Friendly reminder to fix things in MP code that is presently being 105 * XXX: worked on. 106 */ 107#define mp_fixme(string) 108 109#ifdef _KERNEL 110 111/* 112 * Strings for KTR_LOCK tracing. 113 */ 114extern char STR_mtx_lock_slp[]; 115extern char STR_mtx_lock_spn[]; 116extern char STR_mtx_unlock_slp[]; 117extern char STR_mtx_unlock_spn[]; 118 119/* 120 * Prototypes 121 * 122 * NOTE: Functions prepended with `_' (underscore) are exported to other parts 123 * of the kernel via macros, thus allowing us to use the cpp __FILE__ 124 * and __LINE__. These functions should not be called directly by any 125 * code using the IPI. Their macros cover their functionality. 126 * 127 * [See below for descriptions] 128 * 129 */ 130void mtx_init(struct mtx *m, const char *description, int opts); 131void mtx_destroy(struct mtx *m); 132void _mtx_lock_sleep(struct mtx *m, int opts, const char *file, int line); 133void _mtx_unlock_sleep(struct mtx *m, int opts, const char *file, int line); 134void _mtx_lock_spin(struct mtx *m, int opts, critical_t mtx_crit, 135 const char *file, int line); 136void _mtx_unlock_spin(struct mtx *m, int opts, const char *file, int line); 137int _mtx_trylock(struct mtx *m, int opts, const char *file, int line); 138void _mtx_lock_flags(struct mtx *m, int opts, const char *file, int line); 139void _mtx_unlock_flags(struct mtx *m, int opts, const char *file, int line); 140void _mtx_lock_spin_flags(struct mtx *m, int opts, const char *file, 141 int line); 142void _mtx_unlock_spin_flags(struct mtx *m, int opts, const char *file, 143 int line); 144#ifdef INVARIANT_SUPPORT 145void _mtx_assert(struct mtx *m, int what, const char *file, int line); 146#endif 147 148/* 149 * We define our machine-independent (unoptimized) mutex micro-operations 150 * here, if they are not already defined in the machine-dependent mutex.h 151 */ 152 153/* Actually obtain mtx_lock */ 154#ifndef _obtain_lock 155#define _obtain_lock(mp, tid) \ 156 atomic_cmpset_acq_ptr(&(mp)->mtx_lock, (void *)MTX_UNOWNED, (tid)) 157#endif 158 159/* Actually release mtx_lock */ 160#ifndef _release_lock 161#define _release_lock(mp, tid) \ 162 atomic_cmpset_rel_ptr(&(mp)->mtx_lock, (tid), (void *)MTX_UNOWNED) 163#endif 164 165/* Actually release mtx_lock quickly, assuming we own it. */ 166#ifndef _release_lock_quick 167#define _release_lock_quick(mp) \ 168 atomic_store_rel_ptr(&(mp)->mtx_lock, (void *)MTX_UNOWNED) 169#endif 170 171/* 172 * Obtain a sleep lock inline, or call the "hard" function if we can't get it 173 * easy. 174 */ 175#ifndef _get_sleep_lock 176#define _get_sleep_lock(mp, tid, opts, file, line) do { \ 177 if (!_obtain_lock((mp), (tid))) \ 178 _mtx_lock_sleep((mp), (opts), (file), (line)); \ 179} while (0) 180#endif 181 182/* 183 * Obtain a spin lock inline, or call the "hard" function if we can't get it 184 * easy. For spinlocks, we handle recursion inline (it turns out that function 185 * calls can be significantly expensive on some architectures). 186 * Since spin locks are not _too_ common, inlining this code is not too big 187 * a deal. 188 */ 189#ifndef _get_spin_lock 190#define _get_spin_lock(mp, tid, opts, file, line) do { \ 191 critical_t _mtx_crit; \ 192 _mtx_crit = critical_enter(); \ 193 if (!_obtain_lock((mp), (tid))) { \ 194 if ((mp)->mtx_lock == (uintptr_t)(tid)) \ 195 (mp)->mtx_recurse++; \ 196 else \ 197 _mtx_lock_spin((mp), (opts), _mtx_crit, (file), \ 198 (line)); \ 199 } else \ 200 (mp)->mtx_savecrit = _mtx_crit; \ 201} while (0) 202#endif 203 204/* 205 * Release a sleep lock inline, or call the "hard" function if we can't do it 206 * easy. 207 */ 208#ifndef _rel_sleep_lock 209#define _rel_sleep_lock(mp, tid, opts, file, line) do { \ 210 if (!_release_lock((mp), (tid))) \ 211 _mtx_unlock_sleep((mp), (opts), (file), (line)); \ 212} while (0) 213#endif 214 215/* 216 * For spinlocks, we can handle everything inline, as it's pretty simple and 217 * a function call would be too expensive (at least on some architectures). 218 * Since spin locks are not _too_ common, inlining this code is not too big 219 * a deal. 220 */ 221#ifndef _rel_spin_lock 222#define _rel_spin_lock(mp) do { \ 223 critical_t _mtx_crit = (mp)->mtx_savecrit; \ 224 if (mtx_recursed((mp))) \ 225 (mp)->mtx_recurse--; \ 226 else { \ 227 _release_lock_quick((mp)); \ 228 critical_exit(_mtx_crit); \ 229 } \ 230} while (0) 231#endif 232 233/* 234 * Exported lock manipulation interface. 235 * 236 * mtx_lock(m) locks MTX_DEF mutex `m' 237 * 238 * mtx_lock_spin(m) locks MTX_SPIN mutex `m' 239 * 240 * mtx_unlock(m) unlocks MTX_DEF mutex `m' 241 * 242 * mtx_unlock_spin(m) unlocks MTX_SPIN mutex `m' 243 * 244 * mtx_lock_spin_flags(m, opts) and mtx_lock_flags(m, opts) locks mutex `m' 245 * and passes option flags `opts' to the "hard" function, if required. 246 * With these routines, it is possible to pass flags such as MTX_QUIET 247 * and/or MTX_NOSWITCH to the appropriate lock manipulation routines. 248 * 249 * mtx_trylock(m) attempts to acquire MTX_DEF mutex `m' but doesn't sleep if 250 * it cannot. Rather, it returns 0 on failure and non-zero on success. 251 * It does NOT handle recursion as we assume that if a caller is properly 252 * using this part of the interface, he will know that the lock in question 253 * is _not_ recursed. 254 * 255 * mtx_trylock_flags(m, opts) is used the same way as mtx_trylock() but accepts 256 * relevant option flags `opts.' 257 * 258 * mtx_owned(m) returns non-zero if the current thread owns the lock `m' 259 * 260 * mtx_recursed(m) returns non-zero if the lock `m' is presently recursed. 261 */ 262#define mtx_lock(m) mtx_lock_flags((m), 0) 263#define mtx_lock_spin(m) mtx_lock_spin_flags((m), 0) 264#define mtx_trylock(m) mtx_trylock_flags((m), 0) 265#define mtx_unlock(m) mtx_unlock_flags((m), 0) 266#define mtx_unlock_spin(m) mtx_unlock_spin_flags((m), 0) 267 268#ifdef KLD_MODULE 269#define mtx_lock_flags(m, opts) \ 270 _mtx_lock_flags((m), (opts), __FILE__, __LINE__) 271#define mtx_unlock_flags(m, opts) \ 272 _mtx_unlock_flags((m), (opts), __FILE__, __LINE__) 273#define mtx_lock_spin_flags(m, opts) \ 274 _mtx_lock_spin_flags((m), (opts), __FILE__, __LINE__) 275#define mtx_unlock_spin_flags(m, opts) \ 276 _mtx_unlock_spin_flags((m), (opts), __FILE__, __LINE__) 277#else 278#define mtx_lock_flags(m, opts) \ 279 __mtx_lock_flags((m), (opts), __FILE__, __LINE__) 280#define mtx_unlock_flags(m, opts) \ 281 __mtx_unlock_flags((m), (opts), __FILE__, __LINE__) 282#define mtx_lock_spin_flags(m, opts) \ 283 __mtx_lock_spin_flags((m), (opts), __FILE__, __LINE__) 284#define mtx_unlock_spin_flags(m, opts) \ 285 __mtx_unlock_spin_flags((m), (opts), __FILE__, __LINE__) 286#endif 287 288#define __mtx_lock_flags(m, opts, file, line) do { \ 289 MPASS(curproc != NULL); \ 290 KASSERT(((opts) & MTX_NOSWITCH) == 0, \ 291 ("MTX_NOSWITCH used at %s:%d", (file), (line))); \ 292 _get_sleep_lock((m), curproc, (opts), (file), (line)); \ 293 if (((opts) & MTX_QUIET) == 0) \ 294 CTR5(KTR_LOCK, STR_mtx_lock_slp, \ 295 (m)->mtx_description, (m), (m)->mtx_recurse, \ 296 (file), (line)); \ 297 WITNESS_ENTER((m), ((m)->mtx_flags | (opts)), (file), (line)); \ 298} while (0) 299 300#define __mtx_lock_spin_flags(m, opts, file, line) do { \ 301 MPASS(curproc != NULL); \ 302 _get_spin_lock((m), curproc, (opts), (file), (line)); \ 303 if (((opts) & MTX_QUIET) == 0) \ 304 CTR5(KTR_LOCK, STR_mtx_lock_spn, \ 305 (m)->mtx_description, (m), (m)->mtx_recurse, \ 306 (file), (line)); \ 307 WITNESS_ENTER((m), ((m)->mtx_flags | (opts)), (file), (line)); \ 308} while (0) 309 310#define __mtx_unlock_flags(m, opts, file, line) do { \ 311 MPASS(curproc != NULL); \ 312 mtx_assert((m), MA_OWNED); \ 313 WITNESS_EXIT((m), ((m)->mtx_flags | (opts)), (file), (line)); \ 314 _rel_sleep_lock((m), curproc, (opts), (file), (line)); \ 315 if (((opts) & MTX_QUIET) == 0) \ 316 CTR5(KTR_LOCK, STR_mtx_unlock_slp, \ 317 (m)->mtx_description, (m), (m)->mtx_recurse, \ 318 (file), (line)); \ 319} while (0) 320 321#define __mtx_unlock_spin_flags(m, opts, file, line) do { \ 322 MPASS(curproc != NULL); \ 323 mtx_assert((m), MA_OWNED); \ 324 WITNESS_EXIT((m), ((m)->mtx_flags | (opts)), (file), (line)); \ 325 _rel_spin_lock((m)); \ 326 if (((opts) & MTX_QUIET) == 0) \ 327 CTR5(KTR_LOCK, STR_mtx_unlock_spn, \ 328 (m)->mtx_description, (m), (m)->mtx_recurse, \ 329 (file), (line)); \ 330} while (0) 331 332#define mtx_trylock_flags(m, opts) \ 333 _mtx_trylock((m), (opts), __FILE__, __LINE__) 334 335#define mtx_owned(m) (((m)->mtx_lock & MTX_FLAGMASK) == (uintptr_t)curproc) 336 337#define mtx_recursed(m) ((m)->mtx_recurse != 0) 338 339/* 340 * Global locks. 341 */ 342extern struct mtx sched_lock; 343extern struct mtx Giant; 344 345/* 346 * Giant lock manipulation and clean exit macros. 347 * Used to replace return with an exit Giant and return. 348 * 349 * Note that DROP_GIANT*() needs to be paired with PICKUP_GIANT() 350 */ 351#define DROP_GIANT_NOSWITCH() \ 352do { \ 353 int _giantcnt; \ 354 WITNESS_SAVE_DECL(Giant); \ 355 \ 356 if (mtx_owned(&Giant)) \ 357 WITNESS_SAVE(&Giant, Giant); \ 358 for (_giantcnt = 0; mtx_owned(&Giant); _giantcnt++) \ 359 mtx_unlock_flags(&Giant, MTX_NOSWITCH) 360 361#define DROP_GIANT() \ 362do { \ 363 int _giantcnt; \ 364 WITNESS_SAVE_DECL(Giant); \ 365 \ 366 if (mtx_owned(&Giant)) \ 367 WITNESS_SAVE(&Giant, Giant); \ 368 for (_giantcnt = 0; mtx_owned(&Giant); _giantcnt++) \ 369 mtx_unlock(&Giant) 370 371#define PICKUP_GIANT() \ 372 mtx_assert(&Giant, MA_NOTOWNED); \ 373 while (_giantcnt--) \ 374 mtx_lock(&Giant); \ 375 if (mtx_owned(&Giant)) \ 376 WITNESS_RESTORE(&Giant, Giant); \ 377} while (0) 378 379#define PARTIAL_PICKUP_GIANT() \ 380 mtx_assert(&Giant, MA_NOTOWNED); \ 381 while (_giantcnt--) \ 382 mtx_lock(&Giant); \ 383 if (mtx_owned(&Giant)) \ 384 WITNESS_RESTORE(&Giant, Giant) 385 386/* 387 * The INVARIANTS-enabled mtx_assert() functionality. 388 * 389 * The constants need to be defined for INVARIANT_SUPPORT infrastructure 390 * support as _mtx_assert() itself uses them and the latter implies that 391 * _mtx_assert() must build. 392 */ 393#ifdef INVARIANT_SUPPORT 394#define MA_OWNED 0x01 395#define MA_NOTOWNED 0x02 396#define MA_RECURSED 0x04 397#define MA_NOTRECURSED 0x08 398#endif /* INVARIANT_SUPPORT */ 399 400#ifdef INVARIANTS 401#define mtx_assert(m, what) \ 402 _mtx_assert((m), (what), __FILE__, __LINE__) 403 404#else /* INVARIANTS */ 405#define mtx_assert(m, what) 406#endif /* INVARIANTS */ 407 408#define MPASS(ex) MPASS4(ex, #ex, __FILE__, __LINE__) 409#define MPASS2(ex, what) MPASS4(ex, what, __FILE__, __LINE__) 410#define MPASS3(ex, file, line) MPASS4(ex, #ex, file, line) 411#define MPASS4(ex, what, file, line) \ 412 KASSERT((ex), ("Assertion %s failed at %s:%d", what, file, line)) 413 414/* 415 * Exported WITNESS-enabled functions and corresponding wrapper macros. 416 */ 417#ifdef WITNESS 418void witness_save(struct mtx *, const char **, int *); 419void witness_restore(struct mtx *, const char *, int); 420void witness_enter(struct mtx *, int, const char *, int); 421void witness_try_enter(struct mtx *, int, const char *, int); 422void witness_exit(struct mtx *, int, const char *, int); 423int witness_list(struct proc *); 424int witness_sleep(int, struct mtx *, const char *, int); 425 426#define WITNESS_ENTER(m, t, f, l) \ 427 witness_enter((m), (t), (f), (l)) 428 429#define WITNESS_EXIT(m, t, f, l) \ 430 witness_exit((m), (t), (f), (l)) 431 432#define WITNESS_SLEEP(check, m) \ 433 witness_sleep(check, (m), __FILE__, __LINE__) 434 435#define WITNESS_SAVE_DECL(n) \ 436 const char * __CONCAT(n, __wf); \ 437 int __CONCAT(n, __wl) 438 439#define WITNESS_SAVE(m, n) \ 440 witness_save(m, &__CONCAT(n, __wf), &__CONCAT(n, __wl)) 441 442#define WITNESS_RESTORE(m, n) \ 443 witness_restore(m, __CONCAT(n, __wf), __CONCAT(n, __wl)) 444 445#else /* WITNESS */ 446#define witness_enter(m, t, f, l) 447#define witness_tryenter(m, t, f, l) 448#define witness_exit(m, t, f, l) 449#define witness_list(p) 450#define witness_sleep(c, m, f, l) 451 452#define WITNESS_ENTER(m, t, f, l) 453#define WITNESS_EXIT(m, t, f, l) 454#define WITNESS_SLEEP(check, m) 455#define WITNESS_SAVE_DECL(n) 456#define WITNESS_SAVE(m, n) 457#define WITNESS_RESTORE(m, n) 458#endif /* WITNESS */ 459 460#endif /* _KERNEL */ 461#endif /* !LOCORE */ 462#endif /* _SYS_MUTEX_H_ */ 463