lock.h revision 176249
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/lock.h 176249 2008-02-13 20:44:19Z attilio $ 30 */ 31 32#ifndef _SYS_LOCK_H_ 33#define _SYS_LOCK_H_ 34 35#include <sys/queue.h> 36#include <sys/_lock.h> 37 38struct thread; 39 40/* 41 * Lock classes. Each lock has a class which describes characteristics 42 * common to all types of locks of a given class. 43 * 44 * Spin locks in general must always protect against preemption, as it is 45 * an error to perform any type of context switch while holding a spin lock. 46 * Also, for an individual lock to be recursable, its class must allow 47 * recursion and the lock itself must explicitly allow recursion. 48 * 49 * The 'lc_ddb_show' function pointer is used to dump class-specific 50 * data for the 'show lock' DDB command. The 'lc_lock' and 51 * 'lc_unlock' function pointers are used in sleep(9) and cv_wait(9) 52 * to lock and unlock locks while blocking on a sleep queue. The 53 * return value of 'lc_unlock' will be passed to 'lc_lock' on resume 54 * to allow communication of state between the two routines. 55 */ 56 57struct lock_class { 58 const char *lc_name; 59 u_int lc_flags; 60 void (*lc_assert)(struct lock_object *lock, int what); 61 void (*lc_ddb_show)(struct lock_object *lock); 62 void (*lc_lock)(struct lock_object *lock, int how); 63 int (*lc_unlock)(struct lock_object *lock); 64}; 65 66#define LC_SLEEPLOCK 0x00000001 /* Sleep lock. */ 67#define LC_SPINLOCK 0x00000002 /* Spin lock. */ 68#define LC_SLEEPABLE 0x00000004 /* Sleeping allowed with this lock. */ 69#define LC_RECURSABLE 0x00000008 /* Locks of this type may recurse. */ 70#define LC_UPGRADABLE 0x00000010 /* Upgrades and downgrades permitted. */ 71 72#define LO_CLASSFLAGS 0x0000ffff /* Class specific flags. */ 73#define LO_INITIALIZED 0x00010000 /* Lock has been initialized. */ 74#define LO_WITNESS 0x00020000 /* Should witness monitor this lock. */ 75#define LO_QUIET 0x00040000 /* Don't log locking operations. */ 76#define LO_RECURSABLE 0x00080000 /* Lock may recurse. */ 77#define LO_SLEEPABLE 0x00100000 /* Lock may be held while sleeping. */ 78#define LO_UPGRADABLE 0x00200000 /* Lock may be upgraded/downgraded. */ 79#define LO_DUPOK 0x00400000 /* Don't check for duplicate acquires */ 80#define LO_ENROLLPEND 0x00800000 /* On the pending enroll list. */ 81#define LO_CLASSMASK 0x0f000000 /* Class index bitmask. */ 82#define LO_NOPROFILE 0x10000000 /* Don't profile this lock */ 83 84/* 85 * Lock classes are statically assigned an index into the gobal lock_classes 86 * array. Debugging code looks up the lock class for a given lock object 87 * by indexing the array. 88 */ 89#define LO_CLASSSHIFT 24 90#define LO_CLASSINDEX(lock) ((((lock)->lo_flags) & LO_CLASSMASK) >> LO_CLASSSHIFT) 91#define LOCK_CLASS(lock) (lock_classes[LO_CLASSINDEX((lock))]) 92#define LOCK_CLASS_MAX (LO_CLASSMASK >> LO_CLASSSHIFT) 93 94#define LI_RECURSEMASK 0x0000ffff /* Recursion depth of lock instance. */ 95#define LI_EXCLUSIVE 0x00010000 /* Exclusive lock instance. */ 96 97/* 98 * Option flags passed to lock operations that witness also needs to know 99 * about or that are generic across all locks. 100 */ 101#define LOP_NEWORDER 0x00000001 /* Define a new lock order. */ 102#define LOP_QUIET 0x00000002 /* Don't log locking operations. */ 103#define LOP_TRYLOCK 0x00000004 /* Don't check lock order. */ 104#define LOP_EXCLUSIVE 0x00000008 /* Exclusive lock. */ 105#define LOP_DUPOK 0x00000010 /* Don't check for duplicate acquires */ 106 107/* Flags passed to witness_assert. */ 108#define LA_MASKASSERT 0x000000ff /* Mask for witness defined asserts. */ 109#define LA_UNLOCKED 0x00000000 /* Lock is unlocked. */ 110#define LA_LOCKED 0x00000001 /* Lock is at least share locked. */ 111#define LA_SLOCKED 0x00000002 /* Lock is exactly share locked. */ 112#define LA_XLOCKED 0x00000004 /* Lock is exclusively locked. */ 113#define LA_RECURSED 0x00000008 /* Lock is recursed. */ 114#define LA_NOTRECURSED 0x00000010 /* Lock is not recursed. */ 115 116#ifdef _KERNEL 117/* 118 * Lock instances. A lock instance is the data associated with a lock while 119 * it is held by witness. For example, a lock instance will hold the 120 * recursion count of a lock. Lock instances are held in lists. Spin locks 121 * are held in a per-cpu list while sleep locks are held in per-thread list. 122 */ 123struct lock_instance { 124 struct lock_object *li_lock; 125 const char *li_file; /* File and line of last acquire. */ 126 int li_line; 127 u_int li_flags; /* Recursion count and LI_* flags. */ 128}; 129 130/* 131 * A simple list type used to build the list of locks held by a thread 132 * or CPU. We can't simply embed the list in struct lock_object since a 133 * lock may be held by more than one thread if it is a shared lock. Locks 134 * are added to the head of the list, so we fill up each list entry from 135 * "the back" logically. To ease some of the arithmetic, we actually fill 136 * in each list entry the normal way (childer[0] then children[1], etc.) but 137 * when we traverse the list we read children[count-1] as the first entry 138 * down to children[0] as the final entry. 139 */ 140#define LOCK_NCHILDREN 3 141 142struct lock_list_entry { 143 struct lock_list_entry *ll_next; 144 struct lock_instance ll_children[LOCK_NCHILDREN]; 145 u_int ll_count; 146}; 147 148/* 149 * If any of WITNESS, INVARIANTS, or KTR_LOCK KTR tracing has been enabled, 150 * then turn on LOCK_DEBUG. When this option is on, extra debugging 151 * facilities such as tracking the file and line number of lock operations 152 * are enabled. Also, mutex locking operations are not inlined to avoid 153 * bloat from all the extra debugging code. We also have to turn on all the 154 * calling conventions for this debugging code in modules so that modules can 155 * work with both debug and non-debug kernels. 156 */ 157#if defined(KLD_MODULE) || defined(WITNESS) || defined(INVARIANTS) || defined(INVARIANT_SUPPORT) || defined(KTR) || defined(LOCK_PROFILING) 158#define LOCK_DEBUG 1 159#else 160#define LOCK_DEBUG 0 161#endif 162 163/* 164 * In the LOCK_DEBUG case, use the filename and line numbers for debugging 165 * operations. Otherwise, use default values to avoid the unneeded bloat. 166 */ 167#if LOCK_DEBUG > 0 168#define LOCK_FILE __FILE__ 169#define LOCK_LINE __LINE__ 170#else 171#define LOCK_FILE NULL 172#define LOCK_LINE 0 173#endif 174 175/* 176 * Macros for KTR_LOCK tracing. 177 * 178 * opname - name of this operation (LOCK/UNLOCK/SLOCK, etc.) 179 * lo - struct lock_object * for this lock 180 * flags - flags passed to the lock operation 181 * recurse - this locks recursion level (or 0 if class is not recursable) 182 * result - result of a try lock operation 183 * file - file name 184 * line - line number 185 */ 186#define LOCK_LOG_TEST(lo, flags) \ 187 (((flags) & LOP_QUIET) == 0 && ((lo)->lo_flags & LO_QUIET) == 0) 188 189#define LOCK_LOG_LOCK(opname, lo, flags, recurse, file, line) do { \ 190 if (LOCK_LOG_TEST((lo), (flags))) \ 191 CTR5(KTR_LOCK, opname " (%s) %s r = %d at %s:%d", \ 192 LOCK_CLASS(lo)->lc_name, (lo)->lo_name, \ 193 (u_int)(recurse), (file), (line)); \ 194} while (0) 195 196#define LOCK_LOG_TRY(opname, lo, flags, result, file, line) do { \ 197 if (LOCK_LOG_TEST((lo), (flags))) \ 198 CTR5(KTR_LOCK, "TRY_" opname " (%s) %s result=%d at %s:%d",\ 199 LOCK_CLASS(lo)->lc_name, (lo)->lo_name, \ 200 (u_int)(result), (file), (line)); \ 201} while (0) 202 203#define LOCK_LOG_INIT(lo, flags) do { \ 204 if (LOCK_LOG_TEST((lo), (flags))) \ 205 CTR4(KTR_LOCK, "%s: %p (%s) %s", __func__, (lo), \ 206 LOCK_CLASS(lo)->lc_name, (lo)->lo_name); \ 207} while (0) 208 209#define LOCK_LOG_DESTROY(lo, flags) LOCK_LOG_INIT(lo, flags) 210 211#define lock_initalized(lo) ((lo)->lo_flags & LO_INITIALIZED) 212 213/* 214 * Helpful macros for quickly coming up with assertions with informative 215 * panic messages. 216 */ 217#define MPASS(ex) MPASS4(ex, #ex, __FILE__, __LINE__) 218#define MPASS2(ex, what) MPASS4(ex, what, __FILE__, __LINE__) 219#define MPASS3(ex, file, line) MPASS4(ex, #ex, file, line) 220#define MPASS4(ex, what, file, line) \ 221 KASSERT((ex), ("Assertion %s failed at %s:%d", what, file, line)) 222 223extern struct lock_class lock_class_mtx_sleep; 224extern struct lock_class lock_class_mtx_spin; 225extern struct lock_class lock_class_sx; 226extern struct lock_class lock_class_rw; 227extern struct lock_class lock_class_rm; 228extern struct lock_class lock_class_lockmgr; 229 230extern struct lock_class *lock_classes[]; 231 232void lock_init(struct lock_object *, struct lock_class *, 233 const char *, const char *, int); 234void lock_destroy(struct lock_object *); 235void spinlock_enter(void); 236void spinlock_exit(void); 237void witness_init(struct lock_object *); 238void witness_destroy(struct lock_object *); 239int witness_defineorder(struct lock_object *, struct lock_object *); 240void witness_checkorder(struct lock_object *, int, const char *, int); 241void witness_lock(struct lock_object *, int, const char *, int); 242void witness_upgrade(struct lock_object *, int, const char *, int); 243void witness_downgrade(struct lock_object *, int, const char *, int); 244void witness_unlock(struct lock_object *, int, const char *, int); 245void witness_save(struct lock_object *, const char **, int *); 246void witness_restore(struct lock_object *, const char *, int); 247int witness_list_locks(struct lock_list_entry **); 248int witness_warn(int, struct lock_object *, const char *, ...); 249void witness_assert(struct lock_object *, int, const char *, int); 250void witness_display_spinlock(struct lock_object *, struct thread *); 251int witness_line(struct lock_object *); 252const char *witness_file(struct lock_object *); 253 254#ifdef WITNESS 255 256/* Flags for witness_warn(). */ 257#define WARN_GIANTOK 0x01 /* Giant is exempt from this check. */ 258#define WARN_PANIC 0x02 /* Panic if check fails. */ 259#define WARN_SLEEPOK 0x04 /* Sleepable locks are exempt from check. */ 260 261#define WITNESS_INIT(lock) \ 262 witness_init((lock)) 263 264#define WITNESS_DESTROY(lock) \ 265 witness_destroy(lock) 266 267#define WITNESS_CHECKORDER(lock, flags, file, line) \ 268 witness_checkorder((lock), (flags), (file), (line)) 269 270#define WITNESS_DEFINEORDER(lock1, lock2) \ 271 witness_defineorder((struct lock_object *)(lock1), \ 272 (struct lock_object *)(lock2)) 273 274#define WITNESS_LOCK(lock, flags, file, line) \ 275 witness_lock((lock), (flags), (file), (line)) 276 277#define WITNESS_UPGRADE(lock, flags, file, line) \ 278 witness_upgrade((lock), (flags), (file), (line)) 279 280#define WITNESS_DOWNGRADE(lock, flags, file, line) \ 281 witness_downgrade((lock), (flags), (file), (line)) 282 283#define WITNESS_UNLOCK(lock, flags, file, line) \ 284 witness_unlock((lock), (flags), (file), (line)) 285 286#define WITNESS_CHECK(flags, lock, fmt, ...) \ 287 witness_warn((flags), (lock), (fmt), ## __VA_ARGS__) 288 289#define WITNESS_WARN(flags, lock, fmt, ...) \ 290 witness_warn((flags), (lock), (fmt), ## __VA_ARGS__) 291 292#define WITNESS_SAVE_DECL(n) \ 293 const char * __CONCAT(n, __wf); \ 294 int __CONCAT(n, __wl) 295 296#define WITNESS_SAVE(lock, n) \ 297 witness_save((lock), &__CONCAT(n, __wf), &__CONCAT(n, __wl)) 298 299#define WITNESS_RESTORE(lock, n) \ 300 witness_restore((lock), __CONCAT(n, __wf), __CONCAT(n, __wl)) 301 302#define WITNESS_FILE(lock) \ 303 witness_file(lock) 304 305#define WITNESS_LINE(lock) \ 306 witness_line(lock) 307 308#else /* WITNESS */ 309#define WITNESS_INIT(lock) 310#define WITNESS_DESTROY(lock) 311#define WITNESS_DEFINEORDER(lock1, lock2) 0 312#define WITNESS_CHECKORDER(lock, flags, file, line) 313#define WITNESS_LOCK(lock, flags, file, line) 314#define WITNESS_UPGRADE(lock, flags, file, line) 315#define WITNESS_DOWNGRADE(lock, flags, file, line) 316#define WITNESS_UNLOCK(lock, flags, file, line) 317#define WITNESS_CHECK(flags, lock, fmt, ...) 0 318#define WITNESS_WARN(flags, lock, fmt, ...) 319#define WITNESS_SAVE_DECL(n) 320#define WITNESS_SAVE(lock, n) 321#define WITNESS_RESTORE(lock, n) 322#define WITNESS_FILE(lock) ("?") 323#define WITNESS_LINE(lock) (0) 324#endif /* WITNESS */ 325 326/* 327 * Helper macros to allow developers to add explicit lock order checks 328 * wherever they please without having to actually grab a lock to do so. 329 */ 330#define witness_check(l) \ 331 WITNESS_CHECKORDER(&(l)->lock_object, LOP_EXCLUSIVE, LOCK_FILE, \ 332 LOCK_LINE) 333 334#define witness_check_shared(l) \ 335 WITNESS_CHECKORDER(&(l)->lock_object, 0, LOCK_FILE, LOCK_LINE) 336 337#endif /* _KERNEL */ 338#endif /* _SYS_LOCK_H_ */ 339