2 * Copyright (c) 1997 Berkeley Software Design, Inc. All rights reserved.
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28 * from BSDI $Id: mutex.h,v 2.7.2.35 2000/04/27 03:10:26 cp Exp $
35 #include <sys/queue.h>
36 #include <sys/_lock.h>
41 * Lock classes. Each lock has a class which describes characteristics
42 * common to all types of locks of a given class.
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.
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.
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);
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. */
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 */
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.
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)
94 #define LI_RECURSEMASK 0x0000ffff /* Recursion depth of lock instance. */
95 #define LI_EXCLUSIVE 0x00010000 /* Exclusive lock instance. */
98 * Option flags passed to lock operations that witness also needs to know
99 * about or that are generic across all locks.
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 */
107 /* Flags passed to witness_assert. */
108 #define LA_UNLOCKED 0x00000000 /* Lock is unlocked. */
109 #define LA_LOCKED 0x00000001 /* Lock is at least share locked. */
110 #define LA_SLOCKED 0x00000002 /* Lock is exactly share locked. */
111 #define LA_XLOCKED 0x00000004 /* Lock is exclusively locked. */
112 #define LA_RECURSED 0x00000008 /* Lock is recursed. */
113 #define LA_NOTRECURSED 0x00000010 /* Lock is not recursed. */
117 * Lock instances. A lock instance is the data associated with a lock while
118 * it is held by witness. For example, a lock instance will hold the
119 * recursion count of a lock. Lock instances are held in lists. Spin locks
120 * are held in a per-cpu list while sleep locks are held in per-thread list.
122 struct lock_instance {
123 struct lock_object *li_lock;
124 const char *li_file; /* File and line of last acquire. */
126 u_int li_flags; /* Recursion count and LI_* flags. */
130 * A simple list type used to build the list of locks held by a thread
131 * or CPU. We can't simply embed the list in struct lock_object since a
132 * lock may be held by more than one thread if it is a shared lock. Locks
133 * are added to the head of the list, so we fill up each list entry from
134 * "the back" logically. To ease some of the arithmetic, we actually fill
135 * in each list entry the normal way (childer[0] then children[1], etc.) but
136 * when we traverse the list we read children[count-1] as the first entry
137 * down to children[0] as the final entry.
139 #define LOCK_NCHILDREN 3
141 struct lock_list_entry {
142 struct lock_list_entry *ll_next;
143 struct lock_instance ll_children[LOCK_NCHILDREN];
148 * If any of WITNESS, INVARIANTS, or KTR_LOCK KTR tracing has been enabled,
149 * then turn on LOCK_DEBUG. When this option is on, extra debugging
150 * facilities such as tracking the file and line number of lock operations
151 * are enabled. Also, mutex locking operations are not inlined to avoid
152 * bloat from all the extra debugging code. We also have to turn on all the
153 * calling conventions for this debugging code in modules so that modules can
154 * work with both debug and non-debug kernels.
156 #if defined(KLD_MODULE) || defined(WITNESS) || defined(INVARIANTS) || defined(INVARIANT_SUPPORT) || defined(KTR) || defined(LOCK_PROFILING)
163 * In the LOCK_DEBUG case, use the filename and line numbers for debugging
164 * operations. Otherwise, use default values to avoid the unneeded bloat.
167 #define LOCK_FILE __FILE__
168 #define LOCK_LINE __LINE__
170 #define LOCK_FILE NULL
175 * Macros for KTR_LOCK tracing.
177 * opname - name of this operation (LOCK/UNLOCK/SLOCK, etc.)
178 * lo - struct lock_object * for this lock
179 * flags - flags passed to the lock operation
180 * recurse - this locks recursion level (or 0 if class is not recursable)
181 * result - result of a try lock operation
185 #define LOCK_LOG_TEST(lo, flags) \
186 (((flags) & LOP_QUIET) == 0 && ((lo)->lo_flags & LO_QUIET) == 0)
188 #define LOCK_LOG_LOCK(opname, lo, flags, recurse, file, line) do { \
189 if (LOCK_LOG_TEST((lo), (flags))) \
190 CTR5(KTR_LOCK, opname " (%s) %s r = %d at %s:%d", \
191 LOCK_CLASS(lo)->lc_name, (lo)->lo_name, \
192 (u_int)(recurse), (file), (line)); \
195 #define LOCK_LOG_TRY(opname, lo, flags, result, file, line) do { \
196 if (LOCK_LOG_TEST((lo), (flags))) \
197 CTR5(KTR_LOCK, "TRY_" opname " (%s) %s result=%d at %s:%d",\
198 LOCK_CLASS(lo)->lc_name, (lo)->lo_name, \
199 (u_int)(result), (file), (line)); \
202 #define LOCK_LOG_INIT(lo, flags) do { \
203 if (LOCK_LOG_TEST((lo), (flags))) \
204 CTR4(KTR_LOCK, "%s: %p (%s) %s", __func__, (lo), \
205 LOCK_CLASS(lo)->lc_name, (lo)->lo_name); \
208 #define LOCK_LOG_DESTROY(lo, flags) LOCK_LOG_INIT(lo, flags)
210 #define lock_initalized(lo) ((lo)->lo_flags & LO_INITIALIZED)
213 * Helpful macros for quickly coming up with assertions with informative
216 #define MPASS(ex) MPASS4(ex, #ex, __FILE__, __LINE__)
217 #define MPASS2(ex, what) MPASS4(ex, what, __FILE__, __LINE__)
218 #define MPASS3(ex, file, line) MPASS4(ex, #ex, file, line)
219 #define MPASS4(ex, what, file, line) \
220 KASSERT((ex), ("Assertion %s failed at %s:%d", what, file, line))
222 extern struct lock_class lock_class_mtx_sleep;
223 extern struct lock_class lock_class_mtx_spin;
224 extern struct lock_class lock_class_sx;
225 extern struct lock_class lock_class_rw;
226 extern struct lock_class lock_class_rm;
227 extern struct lock_class lock_class_lockmgr;
229 extern struct lock_class *lock_classes[];
231 void lock_init(struct lock_object *, struct lock_class *,
232 const char *, const char *, int);
233 void lock_destroy(struct lock_object *);
234 void spinlock_enter(void);
235 void spinlock_exit(void);
236 void witness_init(struct lock_object *);
237 void witness_destroy(struct lock_object *);
238 int witness_defineorder(struct lock_object *, struct lock_object *);
239 void witness_checkorder(struct lock_object *, int, const char *, int);
240 void witness_lock(struct lock_object *, int, const char *, int);
241 void witness_upgrade(struct lock_object *, int, const char *, int);
242 void witness_downgrade(struct lock_object *, int, const char *, int);
243 void witness_unlock(struct lock_object *, int, const char *, int);
244 void witness_save(struct lock_object *, const char **, int *);
245 void witness_restore(struct lock_object *, const char *, int);
246 int witness_list_locks(struct lock_list_entry **);
247 int witness_warn(int, struct lock_object *, const char *, ...);
248 void witness_assert(struct lock_object *, int, const char *, int);
249 void witness_display_spinlock(struct lock_object *, struct thread *);
250 int witness_line(struct lock_object *);
251 const char *witness_file(struct lock_object *);
255 /* Flags for witness_warn(). */
256 #define WARN_GIANTOK 0x01 /* Giant is exempt from this check. */
257 #define WARN_PANIC 0x02 /* Panic if check fails. */
258 #define WARN_SLEEPOK 0x04 /* Sleepable locks are exempt from check. */
260 #define WITNESS_INIT(lock) \
263 #define WITNESS_DESTROY(lock) \
264 witness_destroy(lock)
266 #define WITNESS_CHECKORDER(lock, flags, file, line) \
267 witness_checkorder((lock), (flags), (file), (line))
269 #define WITNESS_DEFINEORDER(lock1, lock2) \
270 witness_defineorder((struct lock_object *)(lock1), \
271 (struct lock_object *)(lock2))
273 #define WITNESS_LOCK(lock, flags, file, line) \
274 witness_lock((lock), (flags), (file), (line))
276 #define WITNESS_UPGRADE(lock, flags, file, line) \
277 witness_upgrade((lock), (flags), (file), (line))
279 #define WITNESS_DOWNGRADE(lock, flags, file, line) \
280 witness_downgrade((lock), (flags), (file), (line))
282 #define WITNESS_UNLOCK(lock, flags, file, line) \
283 witness_unlock((lock), (flags), (file), (line))
285 #define WITNESS_CHECK(flags, lock, fmt, ...) \
286 witness_warn((flags), (lock), (fmt), ## __VA_ARGS__)
288 #define WITNESS_WARN(flags, lock, fmt, ...) \
289 witness_warn((flags), (lock), (fmt), ## __VA_ARGS__)
291 #define WITNESS_SAVE_DECL(n) \
292 const char * __CONCAT(n, __wf); \
293 int __CONCAT(n, __wl)
295 #define WITNESS_SAVE(lock, n) \
296 witness_save((lock), &__CONCAT(n, __wf), &__CONCAT(n, __wl))
298 #define WITNESS_RESTORE(lock, n) \
299 witness_restore((lock), __CONCAT(n, __wf), __CONCAT(n, __wl))
301 #define WITNESS_FILE(lock) \
304 #define WITNESS_LINE(lock) \
308 #define WITNESS_INIT(lock)
309 #define WITNESS_DESTROY(lock)
310 #define WITNESS_DEFINEORDER(lock1, lock2) 0
311 #define WITNESS_CHECKORDER(lock, flags, file, line)
312 #define WITNESS_LOCK(lock, flags, file, line)
313 #define WITNESS_UPGRADE(lock, flags, file, line)
314 #define WITNESS_DOWNGRADE(lock, flags, file, line)
315 #define WITNESS_UNLOCK(lock, flags, file, line)
316 #define WITNESS_CHECK(flags, lock, fmt, ...) 0
317 #define WITNESS_WARN(flags, lock, fmt, ...)
318 #define WITNESS_SAVE_DECL(n)
319 #define WITNESS_SAVE(lock, n)
320 #define WITNESS_RESTORE(lock, n)
321 #define WITNESS_FILE(lock) ("?")
322 #define WITNESS_LINE(lock) (0)
326 * Helper macros to allow developers to add explicit lock order checks
327 * wherever they please without having to actually grab a lock to do so.
329 #define witness_check(l) \
330 WITNESS_CHECKORDER(&(l)->lock_object, LOP_EXCLUSIVE, LOCK_FILE, \
333 #define witness_check_shared(l) \
334 WITNESS_CHECKORDER(&(l)->lock_object, 0, LOCK_FILE, LOCK_LINE)
337 #endif /* _SYS_LOCK_H_ */