lock.h revision 154077
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 154077 2006-01-06 18:07:32Z 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_SPIN_MUTEX 0 82#define LOCK_CLASS_SLEEP_MUTEX 1 83#define LOCK_CLASS_SX 2 84#define LOCK_CLASS_MAX LOCK_CLASS_SX 85 86#define LI_RECURSEMASK 0x0000ffff /* Recursion depth of lock instance. */ 87#define LI_EXCLUSIVE 0x00010000 /* Exclusive lock instance. */ 88 89/* 90 * Option flags passed to lock operations that witness also needs to know 91 * about or that are generic across all locks. 92 */ 93#define LOP_NEWORDER 0x00000001 /* Define a new lock order. */ 94#define LOP_QUIET 0x00000002 /* Don't log locking operations. */ 95#define LOP_TRYLOCK 0x00000004 /* Don't check lock order. */ 96#define LOP_EXCLUSIVE 0x00000008 /* Exclusive lock. */ 97#define LOP_DUPOK 0x00000010 /* Don't check for duplicate acquires */ 98 99/* Flags passed to witness_assert. */ 100#define LA_UNLOCKED 0x00000000 /* Lock is unlocked. */ 101#define LA_LOCKED 0x00000001 /* Lock is at least share locked. */ 102#define LA_SLOCKED 0x00000002 /* Lock is exactly share locked. */ 103#define LA_XLOCKED 0x00000004 /* Lock is exclusively locked. */ 104#define LA_RECURSED 0x00000008 /* Lock is recursed. */ 105#define LA_NOTRECURSED 0x00000010 /* Lock is not recursed. */ 106 107#ifdef _KERNEL 108/* 109 * Lock instances. A lock instance is the data associated with a lock while 110 * it is held by witness. For example, a lock instance will hold the 111 * recursion count of a lock. Lock instances are held in lists. Spin locks 112 * are held in a per-cpu list while sleep locks are held in per-process list. 113 */ 114struct lock_instance { 115 struct lock_object *li_lock; 116 const char *li_file; /* File and line of last acquire. */ 117 int li_line; 118 u_int li_flags; /* Recursion count and LI_* flags. */ 119}; 120 121/* 122 * A simple list type used to build the list of locks held by a process 123 * or CPU. We can't simply embed the list in struct lock_object since a 124 * lock may be held by more than one process if it is a shared lock. Locks 125 * are added to the head of the list, so we fill up each list entry from 126 * "the back" logically. To ease some of the arithmetic, we actually fill 127 * in each list entry the normal way (childer[0] then children[1], etc.) but 128 * when we traverse the list we read children[count-1] as the first entry 129 * down to children[0] as the final entry. 130 */ 131#define LOCK_NCHILDREN 3 132 133struct lock_list_entry { 134 struct lock_list_entry *ll_next; 135 struct lock_instance ll_children[LOCK_NCHILDREN]; 136 u_int ll_count; 137}; 138 139/* 140 * If any of WITNESS, INVARIANTS, or KTR_LOCK KTR tracing has been enabled, 141 * then turn on LOCK_DEBUG. When this option is on, extra debugging 142 * facilities such as tracking the file and line number of lock operations 143 * are enabled. Also, mutex locking operations are not inlined to avoid 144 * bloat from all the extra debugging code. We also have to turn on all the 145 * calling conventions for this debugging code in modules so that modules can 146 * work with both debug and non-debug kernels. 147 */ 148#if defined(KLD_MODULE) || defined(WITNESS) || defined(INVARIANTS) || defined(INVARIANT_SUPPORT) || defined(KTR) || defined(MUTEX_PROFILING) 149#define LOCK_DEBUG 1 150#else 151#define LOCK_DEBUG 0 152#endif 153 154/* 155 * In the LOCK_DEBUG case, use the filename and line numbers for debugging 156 * operations. Otherwise, use default values to avoid the unneeded bloat. 157 */ 158#if LOCK_DEBUG > 0 159#define LOCK_FILE __FILE__ 160#define LOCK_LINE __LINE__ 161#else 162#define LOCK_FILE NULL 163#define LOCK_LINE 0 164#endif 165 166/* 167 * Macros for KTR_LOCK tracing. 168 * 169 * opname - name of this operation (LOCK/UNLOCK/SLOCK, etc.) 170 * lo - struct lock_object * for this lock 171 * flags - flags passed to the lock operation 172 * recurse - this locks recursion level (or 0 if class is not recursable) 173 * result - result of a try lock operation 174 * file - file name 175 * line - line number 176 */ 177#define LOCK_LOG_TEST(lo, flags) \ 178 (((flags) & LOP_QUIET) == 0 && ((lo)->lo_flags & LO_QUIET) == 0) 179 180#define LOCK_LOG_LOCK(opname, lo, flags, recurse, file, line) do { \ 181 if (LOCK_LOG_TEST((lo), (flags))) \ 182 CTR5(KTR_LOCK, opname " (%s) %s r = %d at %s:%d", \ 183 LOCK_CLASS(lo)->lc_name, (lo)->lo_name, \ 184 (u_int)(recurse), (file), (line)); \ 185} while (0) 186 187#define LOCK_LOG_TRY(opname, lo, flags, result, file, line) do { \ 188 if (LOCK_LOG_TEST((lo), (flags))) \ 189 CTR5(KTR_LOCK, "TRY_" opname " (%s) %s result=%d at %s:%d",\ 190 LOCK_CLASS(lo)->lc_name, (lo)->lo_name, \ 191 (u_int)(result), (file), (line)); \ 192} while (0) 193 194#define LOCK_LOG_INIT(lo, flags) do { \ 195 if (LOCK_LOG_TEST((lo), (flags))) \ 196 CTR4(KTR_LOCK, "%s: %p (%s) %s", __func__, (lo), \ 197 LOCK_CLASS(lo)->lc_name, (lo)->lo_name); \ 198} while (0) 199 200#define LOCK_LOG_DESTROY(lo, flags) LOCK_LOG_INIT(lo, flags) 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; 215 216extern struct lock_class *lock_classes[]; 217 218void spinlock_enter(void); 219void spinlock_exit(void); 220void witness_init(struct lock_object *); 221void witness_destroy(struct lock_object *); 222int witness_defineorder(struct lock_object *, struct lock_object *); 223void witness_checkorder(struct lock_object *, int, const char *, int); 224void witness_lock(struct lock_object *, int, const char *, int); 225void witness_upgrade(struct lock_object *, int, const char *, int); 226void witness_downgrade(struct lock_object *, int, const char *, int); 227void witness_unlock(struct lock_object *, int, const char *, int); 228void witness_save(struct lock_object *, const char **, int *); 229void witness_restore(struct lock_object *, const char *, int); 230int witness_list_locks(struct lock_list_entry **); 231int witness_warn(int, struct lock_object *, const char *, ...); 232void witness_assert(struct lock_object *, int, const char *, int); 233void witness_display_spinlock(struct lock_object *, struct thread *); 234int witness_line(struct lock_object *); 235const char *witness_file(struct lock_object *); 236 237#ifdef WITNESS 238 239/* Flags for witness_warn(). */ 240#define WARN_GIANTOK 0x01 /* Giant is exempt from this check. */ 241#define WARN_PANIC 0x02 /* Panic if check fails. */ 242#define WARN_SLEEPOK 0x04 /* Sleepable locks are exempt from check. */ 243 244#define WITNESS_INIT(lock) \ 245 witness_init((lock)) 246 247#define WITNESS_DESTROY(lock) \ 248 witness_destroy(lock) 249 250#define WITNESS_CHECKORDER(lock, flags, file, line) \ 251 witness_checkorder((lock), (flags), (file), (line)) 252 253#define WITNESS_DEFINEORDER(lock1, lock2) \ 254 witness_defineorder((struct lock_object *)(lock1), \ 255 (struct lock_object *)(lock2)) 256 257#define WITNESS_LOCK(lock, flags, file, line) \ 258 witness_lock((lock), (flags), (file), (line)) 259 260#define WITNESS_UPGRADE(lock, flags, file, line) \ 261 witness_upgrade((lock), (flags), (file), (line)) 262 263#define WITNESS_DOWNGRADE(lock, flags, file, line) \ 264 witness_downgrade((lock), (flags), (file), (line)) 265 266#define WITNESS_UNLOCK(lock, flags, file, line) \ 267 witness_unlock((lock), (flags), (file), (line)) 268 269#define WITNESS_WARN(flags, lock, fmt, ...) \ 270 witness_warn((flags), (lock), (fmt), ## __VA_ARGS__) 271 272#define WITNESS_SAVE_DECL(n) \ 273 const char * __CONCAT(n, __wf); \ 274 int __CONCAT(n, __wl) 275 276#define WITNESS_SAVE(lock, n) \ 277 witness_save((lock), &__CONCAT(n, __wf), &__CONCAT(n, __wl)) 278 279#define WITNESS_RESTORE(lock, n) \ 280 witness_restore((lock), __CONCAT(n, __wf), __CONCAT(n, __wl)) 281 282#define WITNESS_FILE(lock) \ 283 witness_file(lock) 284 285#define WITNESS_LINE(lock) \ 286 witness_line(lock) 287 288#else /* WITNESS */ 289#define WITNESS_INIT(lock) ((lock)->lo_flags |= LO_INITIALIZED) 290#define WITNESS_DESTROY(lock) ((lock)->lo_flags &= ~LO_INITIALIZED) 291#define WITNESS_DEFINEORDER(lock1, lock2) 0 292#define WITNESS_CHECKORDER(lock, flags, file, line) 293#define WITNESS_LOCK(lock, flags, file, line) 294#define WITNESS_UPGRADE(lock, flags, file, line) 295#define WITNESS_DOWNGRADE(lock, flags, file, line) 296#define WITNESS_UNLOCK(lock, flags, file, line) 297#define WITNESS_WARN(flags, lock, fmt, ...) 298#define WITNESS_SAVE_DECL(n) 299#define WITNESS_SAVE(lock, n) 300#define WITNESS_RESTORE(lock, n) 301#define WITNESS_FILE(lock) ("?") 302#define WITNESS_LINE(lock) (0) 303#endif /* WITNESS */ 304 305/* 306 * Helper macros to allow developers to add explicit lock order checks 307 * wherever they please without having to actually grab a lock to do so. 308 */ 309#define witness_check_mutex(m) \ 310 WITNESS_CHECKORDER(&(m)->mtx_object, LOP_EXCLUSIVE, LOCK_FILE, \ 311 LOCK_LINE) 312 313#define witness_check_shared_sx(sx) \ 314 WITNESS_CHECKORDER(&(sx)->sx_object, 0, LOCK_FILE, LOCK_LINE) 315 316#define witness_check_exclusive_sx(sx) \ 317 WITNESS_CHECKORDER(&(sx)->sx_object, LOP_EXCLUSIVE, LOCK_FILE, \ 318 LOCK_LINE) 319 320#endif /* _KERNEL */ 321#endif /* _SYS_LOCK_H_ */ 322