lock.h revision 154484
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 154484 2006-01-17 16:55:17Z jhb $ 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 73/* 74 * Lock classes are statically assigned an index into the gobal lock_classes 75 * array. Debugging code looks up the lock class for a given lock object 76 * by indexing the array. 77 */ 78#define LO_CLASSSHIFT 24 79#define LO_CLASSINDEX(lock) ((((lock)->lo_flags) & LO_CLASSMASK) >> LO_CLASSSHIFT) 80#define LOCK_CLASS(lock) (lock_classes[LO_CLASSINDEX((lock))]) 81#define LOCK_CLASS_MAX (LO_CLASSMASK >> LO_CLASSSHIFT) 82 83#define LI_RECURSEMASK 0x0000ffff /* Recursion depth of lock instance. */ 84#define LI_EXCLUSIVE 0x00010000 /* Exclusive lock instance. */ 85 86/* 87 * Option flags passed to lock operations that witness also needs to know 88 * about or that are generic across all locks. 89 */ 90#define LOP_NEWORDER 0x00000001 /* Define a new lock order. */ 91#define LOP_QUIET 0x00000002 /* Don't log locking operations. */ 92#define LOP_TRYLOCK 0x00000004 /* Don't check lock order. */ 93#define LOP_EXCLUSIVE 0x00000008 /* Exclusive lock. */ 94#define LOP_DUPOK 0x00000010 /* Don't check for duplicate acquires */ 95 96/* Flags passed to witness_assert. */ 97#define LA_UNLOCKED 0x00000000 /* Lock is unlocked. */ 98#define LA_LOCKED 0x00000001 /* Lock is at least share locked. */ 99#define LA_SLOCKED 0x00000002 /* Lock is exactly share locked. */ 100#define LA_XLOCKED 0x00000004 /* Lock is exclusively locked. */ 101#define LA_RECURSED 0x00000008 /* Lock is recursed. */ 102#define LA_NOTRECURSED 0x00000010 /* Lock is not recursed. */ 103 104#ifdef _KERNEL 105/* 106 * Lock instances. A lock instance is the data associated with a lock while 107 * it is held by witness. For example, a lock instance will hold the 108 * recursion count of a lock. Lock instances are held in lists. Spin locks 109 * are held in a per-cpu list while sleep locks are held in per-process list. 110 */ 111struct lock_instance { 112 struct lock_object *li_lock; 113 const char *li_file; /* File and line of last acquire. */ 114 int li_line; 115 u_int li_flags; /* Recursion count and LI_* flags. */ 116}; 117 118/* 119 * A simple list type used to build the list of locks held by a process 120 * or CPU. We can't simply embed the list in struct lock_object since a 121 * lock may be held by more than one process if it is a shared lock. Locks 122 * are added to the head of the list, so we fill up each list entry from 123 * "the back" logically. To ease some of the arithmetic, we actually fill 124 * in each list entry the normal way (childer[0] then children[1], etc.) but 125 * when we traverse the list we read children[count-1] as the first entry 126 * down to children[0] as the final entry. 127 */ 128#define LOCK_NCHILDREN 3 129 130struct lock_list_entry { 131 struct lock_list_entry *ll_next; 132 struct lock_instance ll_children[LOCK_NCHILDREN]; 133 u_int ll_count; 134}; 135 136/* 137 * If any of WITNESS, INVARIANTS, or KTR_LOCK KTR tracing has been enabled, 138 * then turn on LOCK_DEBUG. When this option is on, extra debugging 139 * facilities such as tracking the file and line number of lock operations 140 * are enabled. Also, mutex locking operations are not inlined to avoid 141 * bloat from all the extra debugging code. We also have to turn on all the 142 * calling conventions for this debugging code in modules so that modules can 143 * work with both debug and non-debug kernels. 144 */ 145#if defined(KLD_MODULE) || defined(WITNESS) || defined(INVARIANTS) || defined(INVARIANT_SUPPORT) || defined(KTR) || defined(MUTEX_PROFILING) 146#define LOCK_DEBUG 1 147#else 148#define LOCK_DEBUG 0 149#endif 150 151/* 152 * In the LOCK_DEBUG case, use the filename and line numbers for debugging 153 * operations. Otherwise, use default values to avoid the unneeded bloat. 154 */ 155#if LOCK_DEBUG > 0 156#define LOCK_FILE __FILE__ 157#define LOCK_LINE __LINE__ 158#else 159#define LOCK_FILE NULL 160#define LOCK_LINE 0 161#endif 162 163/* 164 * Macros for KTR_LOCK tracing. 165 * 166 * opname - name of this operation (LOCK/UNLOCK/SLOCK, etc.) 167 * lo - struct lock_object * for this lock 168 * flags - flags passed to the lock operation 169 * recurse - this locks recursion level (or 0 if class is not recursable) 170 * result - result of a try lock operation 171 * file - file name 172 * line - line number 173 */ 174#define LOCK_LOG_TEST(lo, flags) \ 175 (((flags) & LOP_QUIET) == 0 && ((lo)->lo_flags & LO_QUIET) == 0) 176 177#define LOCK_LOG_LOCK(opname, lo, flags, recurse, file, line) do { \ 178 if (LOCK_LOG_TEST((lo), (flags))) \ 179 CTR5(KTR_LOCK, opname " (%s) %s r = %d at %s:%d", \ 180 LOCK_CLASS(lo)->lc_name, (lo)->lo_name, \ 181 (u_int)(recurse), (file), (line)); \ 182} while (0) 183 184#define LOCK_LOG_TRY(opname, lo, flags, result, file, line) do { \ 185 if (LOCK_LOG_TEST((lo), (flags))) \ 186 CTR5(KTR_LOCK, "TRY_" opname " (%s) %s result=%d at %s:%d",\ 187 LOCK_CLASS(lo)->lc_name, (lo)->lo_name, \ 188 (u_int)(result), (file), (line)); \ 189} while (0) 190 191#define LOCK_LOG_INIT(lo, flags) do { \ 192 if (LOCK_LOG_TEST((lo), (flags))) \ 193 CTR4(KTR_LOCK, "%s: %p (%s) %s", __func__, (lo), \ 194 LOCK_CLASS(lo)->lc_name, (lo)->lo_name); \ 195} while (0) 196 197#define LOCK_LOG_DESTROY(lo, flags) LOCK_LOG_INIT(lo, flags) 198 199#define lock_initalized(lo) ((lo)->lo_flags & LO_INITIALIZED) 200 201/* 202 * Helpful macros for quickly coming up with assertions with informative 203 * panic messages. 204 */ 205#define MPASS(ex) MPASS4(ex, #ex, __FILE__, __LINE__) 206#define MPASS2(ex, what) MPASS4(ex, what, __FILE__, __LINE__) 207#define MPASS3(ex, file, line) MPASS4(ex, #ex, file, line) 208#define MPASS4(ex, what, file, line) \ 209 KASSERT((ex), ("Assertion %s failed at %s:%d", what, file, line)) 210 211extern struct lock_class lock_class_mtx_sleep; 212extern struct lock_class lock_class_mtx_spin; 213extern struct lock_class lock_class_sx; 214 215extern struct lock_class *lock_classes[]; 216 217void lock_init(struct lock_object *lock, struct lock_class *class, 218 const char *name, const char *type, int flags); 219void lock_destroy(struct lock_object *lock); 220void spinlock_enter(void); 221void spinlock_exit(void); 222void witness_init(struct lock_object *); 223void witness_destroy(struct lock_object *); 224int witness_defineorder(struct lock_object *, struct lock_object *); 225void witness_checkorder(struct lock_object *, int, const char *, int); 226void witness_lock(struct lock_object *, int, const char *, int); 227void witness_upgrade(struct lock_object *, int, const char *, int); 228void witness_downgrade(struct lock_object *, int, const char *, int); 229void witness_unlock(struct lock_object *, int, const char *, int); 230void witness_save(struct lock_object *, const char **, int *); 231void witness_restore(struct lock_object *, const char *, int); 232int witness_list_locks(struct lock_list_entry **); 233int witness_warn(int, struct lock_object *, const char *, ...); 234void witness_assert(struct lock_object *, int, const char *, int); 235void witness_display_spinlock(struct lock_object *, struct thread *); 236int witness_line(struct lock_object *); 237const char *witness_file(struct lock_object *); 238 239#ifdef WITNESS 240 241/* Flags for witness_warn(). */ 242#define WARN_GIANTOK 0x01 /* Giant is exempt from this check. */ 243#define WARN_PANIC 0x02 /* Panic if check fails. */ 244#define WARN_SLEEPOK 0x04 /* Sleepable locks are exempt from check. */ 245 246#define WITNESS_INIT(lock) \ 247 witness_init((lock)) 248 249#define WITNESS_DESTROY(lock) \ 250 witness_destroy(lock) 251 252#define WITNESS_CHECKORDER(lock, flags, file, line) \ 253 witness_checkorder((lock), (flags), (file), (line)) 254 255#define WITNESS_DEFINEORDER(lock1, lock2) \ 256 witness_defineorder((struct lock_object *)(lock1), \ 257 (struct lock_object *)(lock2)) 258 259#define WITNESS_LOCK(lock, flags, file, line) \ 260 witness_lock((lock), (flags), (file), (line)) 261 262#define WITNESS_UPGRADE(lock, flags, file, line) \ 263 witness_upgrade((lock), (flags), (file), (line)) 264 265#define WITNESS_DOWNGRADE(lock, flags, file, line) \ 266 witness_downgrade((lock), (flags), (file), (line)) 267 268#define WITNESS_UNLOCK(lock, flags, file, line) \ 269 witness_unlock((lock), (flags), (file), (line)) 270 271#define WITNESS_WARN(flags, lock, fmt, ...) \ 272 witness_warn((flags), (lock), (fmt), ## __VA_ARGS__) 273 274#define WITNESS_SAVE_DECL(n) \ 275 const char * __CONCAT(n, __wf); \ 276 int __CONCAT(n, __wl) 277 278#define WITNESS_SAVE(lock, n) \ 279 witness_save((lock), &__CONCAT(n, __wf), &__CONCAT(n, __wl)) 280 281#define WITNESS_RESTORE(lock, n) \ 282 witness_restore((lock), __CONCAT(n, __wf), __CONCAT(n, __wl)) 283 284#define WITNESS_FILE(lock) \ 285 witness_file(lock) 286 287#define WITNESS_LINE(lock) \ 288 witness_line(lock) 289 290#else /* WITNESS */ 291#define WITNESS_INIT(lock) 292#define WITNESS_DESTROY(lock) 293#define WITNESS_DEFINEORDER(lock1, lock2) 0 294#define WITNESS_CHECKORDER(lock, flags, file, line) 295#define WITNESS_LOCK(lock, flags, file, line) 296#define WITNESS_UPGRADE(lock, flags, file, line) 297#define WITNESS_DOWNGRADE(lock, flags, file, line) 298#define WITNESS_UNLOCK(lock, flags, file, line) 299#define WITNESS_WARN(flags, lock, fmt, ...) 300#define WITNESS_SAVE_DECL(n) 301#define WITNESS_SAVE(lock, n) 302#define WITNESS_RESTORE(lock, n) 303#define WITNESS_FILE(lock) ("?") 304#define WITNESS_LINE(lock) (0) 305#endif /* WITNESS */ 306 307/* 308 * Helper macros to allow developers to add explicit lock order checks 309 * wherever they please without having to actually grab a lock to do so. 310 */ 311#define witness_check_mutex(m) \ 312 WITNESS_CHECKORDER(&(m)->mtx_object, LOP_EXCLUSIVE, LOCK_FILE, \ 313 LOCK_LINE) 314 315#define witness_check_shared_sx(sx) \ 316 WITNESS_CHECKORDER(&(sx)->sx_object, 0, LOCK_FILE, LOCK_LINE) 317 318#define witness_check_exclusive_sx(sx) \ 319 WITNESS_CHECKORDER(&(sx)->sx_object, LOP_EXCLUSIVE, LOCK_FILE, \ 320 LOCK_LINE) 321 322#endif /* _KERNEL */ 323#endif /* _SYS_LOCK_H_ */ 324