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freebsd/sys/sys/lock.h

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/*-
* Copyright (c) 1997 Berkeley Software Design, Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Berkeley Software Design Inc's name may not be used to endorse or
* promote products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN INC ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL BERKELEY SOFTWARE DESIGN INC BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* from BSDI $Id: mutex.h,v 2.7.2.35 2000/04/27 03:10:26 cp Exp $
* $FreeBSD$
*/
#ifndef _SYS_LOCK_H_
#define _SYS_LOCK_H_
#include <sys/queue.h>
#include <sys/_lock.h>
struct thread;
/*
* Lock classes. Each lock has a class which describes characteristics
* common to all types of locks of a given class.
*
* Spin locks in general must always protect against preemption, as it is
* an error to perform any type of context switch while holding a spin lock.
* Also, for an individual lock to be recursable, its class must allow
* recursion and the lock itself must explicitly allow recursion.
*/
struct lock_class {
const char *lc_name;
u_int lc_flags;
void (*lc_ddb_show)(struct lock_object *lock);
};
#define LC_SLEEPLOCK 0x00000001 /* Sleep lock. */
#define LC_SPINLOCK 0x00000002 /* Spin lock. */
#define LC_SLEEPABLE 0x00000004 /* Sleeping allowed with this lock. */
#define LC_RECURSABLE 0x00000008 /* Locks of this type may recurse. */
#define LC_UPGRADABLE 0x00000010 /* Upgrades and downgrades permitted. */
#define LO_CLASSFLAGS 0x0000ffff /* Class specific flags. */
#define LO_INITIALIZED 0x00010000 /* Lock has been initialized. */
#define LO_WITNESS 0x00020000 /* Should witness monitor this lock. */
#define LO_QUIET 0x00040000 /* Don't log locking operations. */
#define LO_RECURSABLE 0x00080000 /* Lock may recurse. */
#define LO_SLEEPABLE 0x00100000 /* Lock may be held while sleeping. */
#define LO_UPGRADABLE 0x00200000 /* Lock may be upgraded/downgraded. */
#define LO_DUPOK 0x00400000 /* Don't check for duplicate acquires */
#define LO_ENROLLPEND 0x00800000 /* On the pending enroll list. */
#define LO_CLASSMASK 0x0f000000 /* Class index bitmask. */
/*
* Lock classes are statically assigned an index into the gobal lock_classes
* array. Debugging code looks up the lock class for a given lock object
* by indexing the array.
*/
#define LO_CLASSSHIFT 24
#define LO_CLASSINDEX(lock) ((((lock)->lo_flags) & LO_CLASSMASK) >> LO_CLASSSHIFT)
#define LOCK_CLASS(lock) (lock_classes[LO_CLASSINDEX((lock))])
#define LOCK_CLASS_MAX (LO_CLASSMASK >> LO_CLASSSHIFT)
#define LI_RECURSEMASK 0x0000ffff /* Recursion depth of lock instance. */
#define LI_EXCLUSIVE 0x00010000 /* Exclusive lock instance. */
/*
* Option flags passed to lock operations that witness also needs to know
* about or that are generic across all locks.
*/
#define LOP_NEWORDER 0x00000001 /* Define a new lock order. */
#define LOP_QUIET 0x00000002 /* Don't log locking operations. */
#define LOP_TRYLOCK 0x00000004 /* Don't check lock order. */
#define LOP_EXCLUSIVE 0x00000008 /* Exclusive lock. */
#define LOP_DUPOK 0x00000010 /* Don't check for duplicate acquires */
/* Flags passed to witness_assert. */
#define LA_UNLOCKED 0x00000000 /* Lock is unlocked. */
#define LA_LOCKED 0x00000001 /* Lock is at least share locked. */
#define LA_SLOCKED 0x00000002 /* Lock is exactly share locked. */
#define LA_XLOCKED 0x00000004 /* Lock is exclusively locked. */
#define LA_RECURSED 0x00000008 /* Lock is recursed. */
#define LA_NOTRECURSED 0x00000010 /* Lock is not recursed. */
#ifdef _KERNEL
/*
* Lock instances. A lock instance is the data associated with a lock while
* it is held by witness. For example, a lock instance will hold the
* recursion count of a lock. Lock instances are held in lists. Spin locks
* are held in a per-cpu list while sleep locks are held in per-thread list.
*/
struct lock_instance {
struct lock_object *li_lock;
const char *li_file; /* File and line of last acquire. */
int li_line;
u_int li_flags; /* Recursion count and LI_* flags. */
};
/*
* A simple list type used to build the list of locks held by a thread
* or CPU. We can't simply embed the list in struct lock_object since a
* lock may be held by more than one thread if it is a shared lock. Locks
* are added to the head of the list, so we fill up each list entry from
* "the back" logically. To ease some of the arithmetic, we actually fill
* in each list entry the normal way (childer[0] then children[1], etc.) but
* when we traverse the list we read children[count-1] as the first entry
* down to children[0] as the final entry.
*/
#define LOCK_NCHILDREN 3
struct lock_list_entry {
struct lock_list_entry *ll_next;
struct lock_instance ll_children[LOCK_NCHILDREN];
u_int ll_count;
};
/*
* If any of WITNESS, INVARIANTS, or KTR_LOCK KTR tracing has been enabled,
* then turn on LOCK_DEBUG. When this option is on, extra debugging
* facilities such as tracking the file and line number of lock operations
* are enabled. Also, mutex locking operations are not inlined to avoid
* bloat from all the extra debugging code. We also have to turn on all the
* calling conventions for this debugging code in modules so that modules can
* work with both debug and non-debug kernels.
*/
#if defined(KLD_MODULE) || defined(WITNESS) || defined(INVARIANTS) || defined(INVARIANT_SUPPORT) || defined(KTR) || defined(MUTEX_PROFILING)
#define LOCK_DEBUG 1
#else
#define LOCK_DEBUG 0
#endif
/*
* In the LOCK_DEBUG case, use the filename and line numbers for debugging
* operations. Otherwise, use default values to avoid the unneeded bloat.
*/
#if LOCK_DEBUG > 0
#define LOCK_FILE __FILE__
#define LOCK_LINE __LINE__
#else
#define LOCK_FILE NULL
#define LOCK_LINE 0
#endif
/*
* Macros for KTR_LOCK tracing.
*
* opname - name of this operation (LOCK/UNLOCK/SLOCK, etc.)
* lo - struct lock_object * for this lock
* flags - flags passed to the lock operation
* recurse - this locks recursion level (or 0 if class is not recursable)
* result - result of a try lock operation
* file - file name
* line - line number
*/
#define LOCK_LOG_TEST(lo, flags) \
(((flags) & LOP_QUIET) == 0 && ((lo)->lo_flags & LO_QUIET) == 0)
#define LOCK_LOG_LOCK(opname, lo, flags, recurse, file, line) do { \
if (LOCK_LOG_TEST((lo), (flags))) \
CTR5(KTR_LOCK, opname " (%s) %s r = %d at %s:%d", \
LOCK_CLASS(lo)->lc_name, (lo)->lo_name, \
(u_int)(recurse), (file), (line)); \
} while (0)
#define LOCK_LOG_TRY(opname, lo, flags, result, file, line) do { \
if (LOCK_LOG_TEST((lo), (flags))) \
CTR5(KTR_LOCK, "TRY_" opname " (%s) %s result=%d at %s:%d",\
LOCK_CLASS(lo)->lc_name, (lo)->lo_name, \
(u_int)(result), (file), (line)); \
} while (0)
#define LOCK_LOG_INIT(lo, flags) do { \
if (LOCK_LOG_TEST((lo), (flags))) \
CTR4(KTR_LOCK, "%s: %p (%s) %s", __func__, (lo), \
LOCK_CLASS(lo)->lc_name, (lo)->lo_name); \
} while (0)
#define LOCK_LOG_DESTROY(lo, flags) LOCK_LOG_INIT(lo, flags)
#define lock_initalized(lo) ((lo)->lo_flags & LO_INITIALIZED)
/*
* Helpful macros for quickly coming up with assertions with informative
* panic messages.
*/
#define MPASS(ex) MPASS4(ex, #ex, __FILE__, __LINE__)
#define MPASS2(ex, what) MPASS4(ex, what, __FILE__, __LINE__)
#define MPASS3(ex, file, line) MPASS4(ex, #ex, file, line)
#define MPASS4(ex, what, file, line) \
KASSERT((ex), ("Assertion %s failed at %s:%d", what, file, line))
extern struct lock_class lock_class_mtx_sleep;
extern struct lock_class lock_class_mtx_spin;
extern struct lock_class lock_class_sx;
extern struct lock_class lock_class_rw;
extern struct lock_class *lock_classes[];
void lock_init(struct lock_object *lock, struct lock_class *class,
const char *name, const char *type, int flags);
void lock_destroy(struct lock_object *lock);
void spinlock_enter(void);
void spinlock_exit(void);
void witness_init(struct lock_object *);
void witness_destroy(struct lock_object *);
int witness_defineorder(struct lock_object *, struct lock_object *);
void witness_checkorder(struct lock_object *, int, const char *, int);
void witness_lock(struct lock_object *, int, const char *, int);
void witness_upgrade(struct lock_object *, int, const char *, int);
void witness_downgrade(struct lock_object *, int, const char *, int);
void witness_unlock(struct lock_object *, int, const char *, int);
void witness_save(struct lock_object *, const char **, int *);
void witness_restore(struct lock_object *, const char *, int);
int witness_list_locks(struct lock_list_entry **);
int witness_warn(int, struct lock_object *, const char *, ...);
void witness_assert(struct lock_object *, int, const char *, int);
void witness_display_spinlock(struct lock_object *, struct thread *);
int witness_line(struct lock_object *);
const char *witness_file(struct lock_object *);
#ifdef WITNESS
/* Flags for witness_warn(). */
#define WARN_GIANTOK 0x01 /* Giant is exempt from this check. */
#define WARN_PANIC 0x02 /* Panic if check fails. */
#define WARN_SLEEPOK 0x04 /* Sleepable locks are exempt from check. */
#define WITNESS_INIT(lock) \
witness_init((lock))
#define WITNESS_DESTROY(lock) \
witness_destroy(lock)
#define WITNESS_CHECKORDER(lock, flags, file, line) \
witness_checkorder((lock), (flags), (file), (line))
#define WITNESS_DEFINEORDER(lock1, lock2) \
witness_defineorder((struct lock_object *)(lock1), \
(struct lock_object *)(lock2))
#define WITNESS_LOCK(lock, flags, file, line) \
witness_lock((lock), (flags), (file), (line))
#define WITNESS_UPGRADE(lock, flags, file, line) \
witness_upgrade((lock), (flags), (file), (line))
#define WITNESS_DOWNGRADE(lock, flags, file, line) \
witness_downgrade((lock), (flags), (file), (line))
#define WITNESS_UNLOCK(lock, flags, file, line) \
witness_unlock((lock), (flags), (file), (line))
#define WITNESS_CHECK(flags, lock, fmt, ...) \
witness_warn((flags), (lock), (fmt), ## __VA_ARGS__)
#define WITNESS_WARN(flags, lock, fmt, ...) \
witness_warn((flags), (lock), (fmt), ## __VA_ARGS__)
#define WITNESS_SAVE_DECL(n) \
const char * __CONCAT(n, __wf); \
int __CONCAT(n, __wl)
#define WITNESS_SAVE(lock, n) \
witness_save((lock), &__CONCAT(n, __wf), &__CONCAT(n, __wl))
#define WITNESS_RESTORE(lock, n) \
witness_restore((lock), __CONCAT(n, __wf), __CONCAT(n, __wl))
#define WITNESS_FILE(lock) \
witness_file(lock)
#define WITNESS_LINE(lock) \
witness_line(lock)
#else /* WITNESS */
#define WITNESS_INIT(lock)
#define WITNESS_DESTROY(lock)
#define WITNESS_DEFINEORDER(lock1, lock2) 0
#define WITNESS_CHECKORDER(lock, flags, file, line)
#define WITNESS_LOCK(lock, flags, file, line)
#define WITNESS_UPGRADE(lock, flags, file, line)
#define WITNESS_DOWNGRADE(lock, flags, file, line)
#define WITNESS_UNLOCK(lock, flags, file, line)
#define WITNESS_CHECK(flags, lock, fmt, ...) 0
#define WITNESS_WARN(flags, lock, fmt, ...)
#define WITNESS_SAVE_DECL(n)
#define WITNESS_SAVE(lock, n)
#define WITNESS_RESTORE(lock, n)
#define WITNESS_FILE(lock) ("?")
#define WITNESS_LINE(lock) (0)
#endif /* WITNESS */
/*
* Helper macros to allow developers to add explicit lock order checks
* wherever they please without having to actually grab a lock to do so.
*/
#define witness_check_mutex(m) \
WITNESS_CHECKORDER(&(m)->mtx_object, LOP_EXCLUSIVE, LOCK_FILE, \
LOCK_LINE)
#define witness_check_shared_sx(sx) \
WITNESS_CHECKORDER(&(sx)->sx_object, 0, LOCK_FILE, LOCK_LINE)
#define witness_check_exclusive_sx(sx) \
WITNESS_CHECKORDER(&(sx)->sx_object, LOP_EXCLUSIVE, LOCK_FILE, \
LOCK_LINE)
#endif /* _KERNEL */
#endif /* _SYS_LOCK_H_ */
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