lock.h revision 111881
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 111881 2003-03-04 20:56:39Z 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}; 54 55#define LC_SLEEPLOCK 0x00000001 /* Sleep lock. */ 56#define LC_SPINLOCK 0x00000002 /* Spin lock. */ 57#define LC_SLEEPABLE 0x00000004 /* Sleeping allowed with this lock. */ 58#define LC_RECURSABLE 0x00000008 /* Locks of this type may recurse. */ 59#define LC_UPGRADABLE 0x00000010 /* Upgrades and downgrades permitted. */ 60 61#define LO_CLASSFLAGS 0x0000ffff /* Class specific flags. */ 62#define LO_INITIALIZED 0x00010000 /* Lock has been initialized. */ 63#define LO_WITNESS 0x00020000 /* Should witness monitor this lock. */ 64#define LO_QUIET 0x00040000 /* Don't log locking operations. */ 65#define LO_RECURSABLE 0x00080000 /* Lock may recurse. */ 66#define LO_SLEEPABLE 0x00100000 /* Lock may be held while sleeping. */ 67#define LO_UPGRADABLE 0x00200000 /* Lock may be upgraded/downgraded. */ 68#define LO_DUPOK 0x00400000 /* Don't check for duplicate acquires */ 69 70#define LI_RECURSEMASK 0x0000ffff /* Recursion depth of lock instance. */ 71#define LI_EXCLUSIVE 0x00010000 /* Exclusive lock instance. */ 72 73/* 74 * Option flags passed to lock operations that witness also needs to know 75 * about or that are generic across all locks. 76 */ 77#define LOP_QUIET 0x00000002 /* Don't log locking operations. */ 78#define LOP_TRYLOCK 0x00000004 /* Don't check lock order. */ 79#define LOP_EXCLUSIVE 0x00000008 /* Exclusive lock. */ 80 81/* Flags passed to witness_assert. */ 82#define LA_UNLOCKED 0x00000000 /* Lock is unlocked. */ 83#define LA_LOCKED 0x00000001 /* Lock is at least share locked. */ 84#define LA_SLOCKED 0x00000002 /* Lock is exactly share locked. */ 85#define LA_XLOCKED 0x00000004 /* Lock is exclusively locked. */ 86#define LA_RECURSED 0x00000008 /* Lock is recursed. */ 87#define LA_NOTRECURSED 0x00000010 /* Lock is not recursed. */ 88 89#ifdef _KERNEL 90/* 91 * Lock instances. A lock instance is the data associated with a lock while 92 * it is held by witness. For example, a lock instance will hold the 93 * recursion count of a lock. Lock instances are held in lists. Spin locks 94 * are held in a per-cpu list while sleep locks are held in per-process list. 95 */ 96struct lock_instance { 97 struct lock_object *li_lock; 98 const char *li_file; /* File and line of last acquire. */ 99 int li_line; 100 u_int li_flags; /* Recursion count and LI_* flags. */ 101}; 102 103/* 104 * A simple list type used to build the list of locks held by a process 105 * or CPU. We can't simply embed the list in struct lock_object since a 106 * lock may be held by more than one process if it is a shared lock. Locks 107 * are added to the head of the list, so we fill up each list entry from 108 * "the back" logically. To ease some of the arithmetic, we actually fill 109 * in each list entry the normal way (childer[0] then children[1], etc.) but 110 * when we traverse the list we read children[count-1] as the first entry 111 * down to children[0] as the final entry. 112 */ 113#define LOCK_NCHILDREN 3 114 115struct lock_list_entry { 116 struct lock_list_entry *ll_next; 117 struct lock_instance ll_children[LOCK_NCHILDREN]; 118 u_int ll_count; 119}; 120 121/* 122 * If any of WITNESS, INVARIANTS, or KTR_LOCK KTR tracing has been enabled, 123 * then turn on LOCK_DEBUG. When this option is on, extra debugging 124 * facilities such as tracking the file and line number of lock operations 125 * are enabled. Also, mutex locking operations are not inlined to avoid 126 * bloat from all the extra debugging code. We also have to turn on all the 127 * calling conventions for this debugging code in modules so that modules can 128 * work with both debug and non-debug kernels. 129 */ 130#if defined(KLD_MODULE) || defined(WITNESS) || defined(INVARIANTS) || defined(INVARIANT_SUPPORT) || defined(KTR) 131#define LOCK_DEBUG 1 132#else 133#define LOCK_DEBUG 0 134#endif 135 136/* 137 * In the LOCK_DEBUG case, use the filename and line numbers for debugging 138 * operations. Otherwise, use default values to avoid the unneeded bloat. 139 */ 140#if LOCK_DEBUG > 0 141#define LOCK_FILE __FILE__ 142#define LOCK_LINE __LINE__ 143#else 144#define LOCK_FILE NULL 145#define LOCK_LINE 0 146#endif 147 148/* 149 * Macros for KTR_LOCK tracing. 150 * 151 * opname - name of this operation (LOCK/UNLOCK/SLOCK, etc.) 152 * lo - struct lock_object * for this lock 153 * flags - flags passed to the lock operation 154 * recurse - this locks recursion level (or 0 if class is not recursable) 155 * result - result of a try lock operation 156 * file - file name 157 * line - line number 158 */ 159#define LOCK_LOG_TEST(lo, flags) \ 160 (((flags) & LOP_QUIET) == 0 && ((lo)->lo_flags & LO_QUIET) == 0) 161 162#define LOCK_LOG_LOCK(opname, lo, flags, recurse, file, line) do { \ 163 if (LOCK_LOG_TEST((lo), (flags))) \ 164 CTR5(KTR_LOCK, opname " (%s) %s r = %d at %s:%d", \ 165 (lo)->lo_class->lc_name, (lo)->lo_name, \ 166 (u_int)(recurse), (file), (line)); \ 167} while (0) 168 169#define LOCK_LOG_TRY(opname, lo, flags, result, file, line) do { \ 170 if (LOCK_LOG_TEST((lo), (flags))) \ 171 CTR5(KTR_LOCK, "TRY_" opname " (%s) %s result=%d at %s:%d",\ 172 (lo)->lo_class->lc_name, (lo)->lo_name, \ 173 (u_int)(result), (file), (line)); \ 174} while (0) 175 176#define LOCK_LOG_INIT(lo, flags) do { \ 177 if (LOCK_LOG_TEST((lo), (flags))) \ 178 CTR4(KTR_LOCK, "%s: %p (%s) %s", __func__, (lo), \ 179 (lo)->lo_class->lc_name, (lo)->lo_name); \ 180} while (0) 181 182#define LOCK_LOG_DESTROY(lo, flags) LOCK_LOG_INIT(lo, flags) 183 184/* 185 * Helpful macros for quickly coming up with assertions with informative 186 * panic messages. 187 */ 188#define MPASS(ex) MPASS4(ex, #ex, __FILE__, __LINE__) 189#define MPASS2(ex, what) MPASS4(ex, what, __FILE__, __LINE__) 190#define MPASS3(ex, file, line) MPASS4(ex, #ex, file, line) 191#define MPASS4(ex, what, file, line) \ 192 KASSERT((ex), ("Assertion %s failed at %s:%d", what, file, line)) 193 194extern struct lock_class lock_class_mtx_sleep; 195extern struct lock_class lock_class_mtx_spin; 196extern struct lock_class lock_class_sx; 197 198void witness_init(struct lock_object *); 199void witness_destroy(struct lock_object *); 200void witness_lock(struct lock_object *, int, const char *, int); 201void witness_upgrade(struct lock_object *, int, const char *, int); 202void witness_downgrade(struct lock_object *, int, const char *, int); 203void witness_unlock(struct lock_object *, int, const char *, int); 204void witness_save(struct lock_object *, const char **, int *); 205void witness_restore(struct lock_object *, const char *, int); 206int witness_list_locks(struct lock_list_entry **); 207int witness_warn(int, struct lock_object *, const char *, ...); 208void witness_assert(struct lock_object *, int, const char *, int); 209int witness_line(struct lock_object *); 210const char *witness_file(struct lock_object *); 211 212#ifdef WITNESS 213 214/* Flags for witness_warn(). */ 215#define WARN_GIANTOK 0x01 /* Giant is exempt from this check. */ 216#define WARN_PANIC 0x02 /* Panic if check fails. */ 217#define WARN_SLEEPOK 0x04 /* Sleepable locks are exempt from check. */ 218 219#define WITNESS_INIT(lock) \ 220 witness_init((lock)) 221 222#define WITNESS_DESTROY(lock) \ 223 witness_destroy(lock) 224 225#define WITNESS_LOCK(lock, flags, file, line) \ 226 witness_lock((lock), (flags), (file), (line)) 227 228#define WITNESS_UPGRADE(lock, flags, file, line) \ 229 witness_upgrade((lock), (flags), (file), (line)) 230 231#define WITNESS_DOWNGRADE(lock, flags, file, line) \ 232 witness_downgrade((lock), (flags), (file), (line)) 233 234#define WITNESS_UNLOCK(lock, flags, file, line) \ 235 witness_unlock((lock), (flags), (file), (line)) 236 237#define WITNESS_WARN(flags, lock, fmt, ...) \ 238 witness_warn((flags), (lock), (fmt), ## __VA_ARGS__) 239 240#define WITNESS_SAVE_DECL(n) \ 241 const char * __CONCAT(n, __wf); \ 242 int __CONCAT(n, __wl) 243 244#define WITNESS_SAVE(lock, n) \ 245 witness_save((lock), &__CONCAT(n, __wf), &__CONCAT(n, __wl)) 246 247#define WITNESS_RESTORE(lock, n) \ 248 witness_restore((lock), __CONCAT(n, __wf), __CONCAT(n, __wl)) 249 250#define WITNESS_FILE(lock) \ 251 witness_file(lock) 252 253#define WITNESS_LINE(lock) \ 254 witness_line(lock) 255 256#else /* WITNESS */ 257#define WITNESS_INIT(lock) ((lock)->lo_flags |= LO_INITIALIZED) 258#define WITNESS_DESTROY(lock) ((lock)->lo_flags &= ~LO_INITIALIZED) 259#define WITNESS_LOCK(lock, flags, file, line) 260#define WITNESS_UPGRADE(lock, flags, file, line) 261#define WITNESS_DOWNGRADE(lock, flags, file, line) 262#define WITNESS_UNLOCK(lock, flags, file, line) 263#define WITNESS_WARN(flags, lock, fmt, ...) 264#define WITNESS_SAVE_DECL(n) 265#define WITNESS_SAVE(lock, n) 266#define WITNESS_RESTORE(lock, n) 267#define WITNESS_FILE(lock) ("?") 268#define WITNESS_LINE(lock) (0) 269#endif /* WITNESS */ 270 271#endif /* _KERNEL */ 272#endif /* _SYS_LOCK_H_ */ 273