lock.h revision 164247
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 164246 2006-11-13 05:41:46Z kmacy $ 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 50struct lock_class { 51 const char *lc_name; 52 u_int lc_flags; 53 void (*lc_ddb_show)(struct lock_object *lock); 54}; 55 56#define LC_SLEEPLOCK 0x00000001 /* Sleep lock. */ 57#define LC_SPINLOCK 0x00000002 /* Spin lock. */ 58#define LC_SLEEPABLE 0x00000004 /* Sleeping allowed with this lock. */ 59#define LC_RECURSABLE 0x00000008 /* Locks of this type may recurse. */ 60#define LC_UPGRADABLE 0x00000010 /* Upgrades and downgrades permitted. */ 61 62#define LO_CLASSFLAGS 0x0000ffff /* Class specific flags. */ 63#define LO_INITIALIZED 0x00010000 /* Lock has been initialized. */ 64#define LO_WITNESS 0x00020000 /* Should witness monitor this lock. */ 65#define LO_QUIET 0x00040000 /* Don't log locking operations. */ 66#define LO_RECURSABLE 0x00080000 /* Lock may recurse. */ 67#define LO_SLEEPABLE 0x00100000 /* Lock may be held while sleeping. */ 68#define LO_UPGRADABLE 0x00200000 /* Lock may be upgraded/downgraded. */ 69#define LO_DUPOK 0x00400000 /* Don't check for duplicate acquires */ 70#define LO_ENROLLPEND 0x00800000 /* On the pending enroll list. */ 71#define LO_CLASSMASK 0x0f000000 /* Class index bitmask. */ 72#define LO_NOPROFILE 0x10000000 /* Don't profile this lock */ 73 74/* 75 * Lock classes are statically assigned an index into the gobal lock_classes 76 * array. Debugging code looks up the lock class for a given lock object 77 * by indexing the array. 78 */ 79#define LO_CLASSSHIFT 24 80#define LO_CLASSINDEX(lock) ((((lock)->lo_flags) & LO_CLASSMASK) >> LO_CLASSSHIFT) 81#define LOCK_CLASS(lock) (lock_classes[LO_CLASSINDEX((lock))]) 82#define LOCK_CLASS_MAX (LO_CLASSMASK >> LO_CLASSSHIFT) 83 84#define LI_RECURSEMASK 0x0000ffff /* Recursion depth of lock instance. */ 85#define LI_EXCLUSIVE 0x00010000 /* Exclusive lock instance. */ 86 87/* 88 * Option flags passed to lock operations that witness also needs to know 89 * about or that are generic across all locks. 90 */ 91#define LOP_NEWORDER 0x00000001 /* Define a new lock order. */ 92#define LOP_QUIET 0x00000002 /* Don't log locking operations. */ 93#define LOP_TRYLOCK 0x00000004 /* Don't check lock order. */ 94#define LOP_EXCLUSIVE 0x00000008 /* Exclusive lock. */ 95#define LOP_DUPOK 0x00000010 /* Don't check for duplicate acquires */ 96 97/* Flags passed to witness_assert. */ 98#define LA_UNLOCKED 0x00000000 /* Lock is unlocked. */ 99#define LA_LOCKED 0x00000001 /* Lock is at least share locked. */ 100#define LA_SLOCKED 0x00000002 /* Lock is exactly share locked. */ 101#define LA_XLOCKED 0x00000004 /* Lock is exclusively locked. */ 102#define LA_RECURSED 0x00000008 /* Lock is recursed. */ 103#define LA_NOTRECURSED 0x00000010 /* Lock is not recursed. */ 104 105#ifdef _KERNEL 106/* 107 * Lock instances. A lock instance is the data associated with a lock while 108 * it is held by witness. For example, a lock instance will hold the 109 * recursion count of a lock. Lock instances are held in lists. Spin locks 110 * are held in a per-cpu list while sleep locks are held in per-thread list. 111 */ 112struct lock_instance { 113 struct lock_object *li_lock; 114 const char *li_file; /* File and line of last acquire. */ 115 int li_line; 116 u_int li_flags; /* Recursion count and LI_* flags. */ 117}; 118 119/* 120 * A simple list type used to build the list of locks held by a thread 121 * or CPU. We can't simply embed the list in struct lock_object since a 122 * lock may be held by more than one thread if it is a shared lock. Locks 123 * are added to the head of the list, so we fill up each list entry from 124 * "the back" logically. To ease some of the arithmetic, we actually fill 125 * in each list entry the normal way (childer[0] then children[1], etc.) but 126 * when we traverse the list we read children[count-1] as the first entry 127 * down to children[0] as the final entry. 128 */ 129#define LOCK_NCHILDREN 3 130 131struct lock_list_entry { 132 struct lock_list_entry *ll_next; 133 struct lock_instance ll_children[LOCK_NCHILDREN]; 134 u_int ll_count; 135}; 136 137/* 138 * If any of WITNESS, INVARIANTS, or KTR_LOCK KTR tracing has been enabled, 139 * then turn on LOCK_DEBUG. When this option is on, extra debugging 140 * facilities such as tracking the file and line number of lock operations 141 * are enabled. Also, mutex locking operations are not inlined to avoid 142 * bloat from all the extra debugging code. We also have to turn on all the 143 * calling conventions for this debugging code in modules so that modules can 144 * work with both debug and non-debug kernels. 145 */ 146#if defined(KLD_MODULE) || defined(WITNESS) || defined(INVARIANTS) || defined(INVARIANT_SUPPORT) || defined(KTR) || defined(LOCK_PROFILING) 147#define LOCK_DEBUG 1 148#else 149#define LOCK_DEBUG 0 150#endif 151 152/* 153 * In the LOCK_DEBUG case, use the filename and line numbers for debugging 154 * operations. Otherwise, use default values to avoid the unneeded bloat. 155 */ 156#if LOCK_DEBUG > 0 157#define LOCK_FILE __FILE__ 158#define LOCK_LINE __LINE__ 159#else 160#define LOCK_FILE NULL 161#define LOCK_LINE 0 162#endif 163 164/* 165 * Macros for KTR_LOCK tracing. 166 * 167 * opname - name of this operation (LOCK/UNLOCK/SLOCK, etc.) 168 * lo - struct lock_object * for this lock 169 * flags - flags passed to the lock operation 170 * recurse - this locks recursion level (or 0 if class is not recursable) 171 * result - result of a try lock operation 172 * file - file name 173 * line - line number 174 */ 175#define LOCK_LOG_TEST(lo, flags) \ 176 (((flags) & LOP_QUIET) == 0 && ((lo)->lo_flags & LO_QUIET) == 0) 177 178#define LOCK_LOG_LOCK(opname, lo, flags, recurse, file, line) do { \ 179 if (LOCK_LOG_TEST((lo), (flags))) \ 180 CTR5(KTR_LOCK, opname " (%s) %s r = %d at %s:%d", \ 181 LOCK_CLASS(lo)->lc_name, (lo)->lo_name, \ 182 (u_int)(recurse), (file), (line)); \ 183} while (0) 184 185#define LOCK_LOG_TRY(opname, lo, flags, result, file, line) do { \ 186 if (LOCK_LOG_TEST((lo), (flags))) \ 187 CTR5(KTR_LOCK, "TRY_" opname " (%s) %s result=%d at %s:%d",\ 188 LOCK_CLASS(lo)->lc_name, (lo)->lo_name, \ 189 (u_int)(result), (file), (line)); \ 190} while (0) 191 192#define LOCK_LOG_INIT(lo, flags) do { \ 193 if (LOCK_LOG_TEST((lo), (flags))) \ 194 CTR4(KTR_LOCK, "%s: %p (%s) %s", __func__, (lo), \ 195 LOCK_CLASS(lo)->lc_name, (lo)->lo_name); \ 196} while (0) 197 198#define LOCK_LOG_DESTROY(lo, flags) LOCK_LOG_INIT(lo, flags) 199 200#define lock_initalized(lo) ((lo)->lo_flags & LO_INITIALIZED) 201 202/* 203 * Helpful macros for quickly coming up with assertions with informative 204 * panic messages. 205 */ 206#define MPASS(ex) MPASS4(ex, #ex, __FILE__, __LINE__) 207#define MPASS2(ex, what) MPASS4(ex, what, __FILE__, __LINE__) 208#define MPASS3(ex, file, line) MPASS4(ex, #ex, file, line) 209#define MPASS4(ex, what, file, line) \ 210 KASSERT((ex), ("Assertion %s failed at %s:%d", what, file, line)) 211 212extern struct lock_class lock_class_mtx_sleep; 213extern struct lock_class lock_class_mtx_spin; 214extern struct lock_class lock_class_sx; 215extern struct lock_class lock_class_rw; 216extern struct lock_class lock_class_lockmgr; 217 218extern struct lock_class *lock_classes[]; 219 220void lock_init(struct lock_object *lock, struct lock_class *class, 221 const char *name, const char *type, int flags); 222void lock_destroy(struct lock_object *lock); 223void spinlock_enter(void); 224void spinlock_exit(void); 225void witness_init(struct lock_object *); 226void witness_destroy(struct lock_object *); 227int witness_defineorder(struct lock_object *, struct lock_object *); 228void witness_checkorder(struct lock_object *, int, const char *, int); 229void witness_lock(struct lock_object *, int, const char *, int); 230void witness_upgrade(struct lock_object *, int, const char *, int); 231void witness_downgrade(struct lock_object *, int, const char *, int); 232void witness_unlock(struct lock_object *, int, const char *, int); 233void witness_save(struct lock_object *, const char **, int *); 234void witness_restore(struct lock_object *, const char *, int); 235int witness_list_locks(struct lock_list_entry **); 236int witness_warn(int, struct lock_object *, const char *, ...); 237void witness_assert(struct lock_object *, int, const char *, int); 238void witness_display_spinlock(struct lock_object *, struct thread *); 239int witness_line(struct lock_object *); 240const char *witness_file(struct lock_object *); 241 242#ifdef WITNESS 243 244/* Flags for witness_warn(). */ 245#define WARN_GIANTOK 0x01 /* Giant is exempt from this check. */ 246#define WARN_PANIC 0x02 /* Panic if check fails. */ 247#define WARN_SLEEPOK 0x04 /* Sleepable locks are exempt from check. */ 248 249#define WITNESS_INIT(lock) \ 250 witness_init((lock)) 251 252#define WITNESS_DESTROY(lock) \ 253 witness_destroy(lock) 254 255#define WITNESS_CHECKORDER(lock, flags, file, line) \ 256 witness_checkorder((lock), (flags), (file), (line)) 257 258#define WITNESS_DEFINEORDER(lock1, lock2) \ 259 witness_defineorder((struct lock_object *)(lock1), \ 260 (struct lock_object *)(lock2)) 261 262#define WITNESS_LOCK(lock, flags, file, line) \ 263 witness_lock((lock), (flags), (file), (line)) 264 265#define WITNESS_UPGRADE(lock, flags, file, line) \ 266 witness_upgrade((lock), (flags), (file), (line)) 267 268#define WITNESS_DOWNGRADE(lock, flags, file, line) \ 269 witness_downgrade((lock), (flags), (file), (line)) 270 271#define WITNESS_UNLOCK(lock, flags, file, line) \ 272 witness_unlock((lock), (flags), (file), (line)) 273 274#define WITNESS_CHECK(flags, lock, fmt, ...) \ 275 witness_warn((flags), (lock), (fmt), ## __VA_ARGS__) 276 277#define WITNESS_WARN(flags, lock, fmt, ...) \ 278 witness_warn((flags), (lock), (fmt), ## __VA_ARGS__) 279 280#define WITNESS_SAVE_DECL(n) \ 281 const char * __CONCAT(n, __wf); \ 282 int __CONCAT(n, __wl) 283 284#define WITNESS_SAVE(lock, n) \ 285 witness_save((lock), &__CONCAT(n, __wf), &__CONCAT(n, __wl)) 286 287#define WITNESS_RESTORE(lock, n) \ 288 witness_restore((lock), __CONCAT(n, __wf), __CONCAT(n, __wl)) 289 290#define WITNESS_FILE(lock) \ 291 witness_file(lock) 292 293#define WITNESS_LINE(lock) \ 294 witness_line(lock) 295 296#else /* WITNESS */ 297#define WITNESS_INIT(lock) 298#define WITNESS_DESTROY(lock) 299#define WITNESS_DEFINEORDER(lock1, lock2) 0 300#define WITNESS_CHECKORDER(lock, flags, file, line) 301#define WITNESS_LOCK(lock, flags, file, line) 302#define WITNESS_UPGRADE(lock, flags, file, line) 303#define WITNESS_DOWNGRADE(lock, flags, file, line) 304#define WITNESS_UNLOCK(lock, flags, file, line) 305#define WITNESS_CHECK(flags, lock, fmt, ...) 0 306#define WITNESS_WARN(flags, lock, fmt, ...) 307#define WITNESS_SAVE_DECL(n) 308#define WITNESS_SAVE(lock, n) 309#define WITNESS_RESTORE(lock, n) 310#define WITNESS_FILE(lock) ("?") 311#define WITNESS_LINE(lock) (0) 312#endif /* WITNESS */ 313 314/* 315 * Helper macros to allow developers to add explicit lock order checks 316 * wherever they please without having to actually grab a lock to do so. 317 */ 318#define witness_check_mutex(m) \ 319 WITNESS_CHECKORDER(&(m)->mtx_object, LOP_EXCLUSIVE, LOCK_FILE, \ 320 LOCK_LINE) 321 322#define witness_check_shared_sx(sx) \ 323 WITNESS_CHECKORDER(&(sx)->sx_object, 0, LOCK_FILE, LOCK_LINE) 324 325#define witness_check_exclusive_sx(sx) \ 326 WITNESS_CHECKORDER(&(sx)->sx_object, LOP_EXCLUSIVE, LOCK_FILE, \ 327 LOCK_LINE) 328 329#endif /* _KERNEL */ 330#endif /* _SYS_LOCK_H_ */ 331