/* $OpenBSD: kern_lock.c,v 1.25 2007/03/15 10:22:30 art Exp $ */ /* * Copyright (c) 1995 * The Regents of the University of California. All rights reserved. * * This code contains ideas from software contributed to Berkeley by * Avadis Tevanian, Jr., Michael Wayne Young, and the Mach Operating * System project at Carnegie-Mellon University. * * 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. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 THE REGENTS OR CONTRIBUTORS 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. * * @(#)kern_lock.c 8.18 (Berkeley) 5/21/95 */ #include #include #include #include #include #include #ifndef spllock #define spllock() splhigh() #endif #ifdef MULTIPROCESSOR #define CPU_NUMBER() cpu_number() #else #define CPU_NUMBER() 0 #endif void record_stacktrace(int *, int); void playback_stacktrace(int *, int); /* * Locking primitives implementation. * Locks provide shared/exclusive synchronization. */ #if defined(LOCKDEBUG) || defined(DIAGNOSTIC) /* { */ #define COUNT(lkp, p, cpu_id, x) \ (p)->p_locks += (x) #else #define COUNT(lkp, p, cpu_id, x) #endif /* LOCKDEBUG || DIAGNOSTIC */ /* } */ #define INTERLOCK_ACQUIRE(lkp, flags) \ do { \ simple_lock(&(lkp)->lk_interlock); \ } while (/*CONSTCOND*/ 0) #define INTERLOCK_RELEASE(lkp, flags) \ do { \ simple_unlock(&(lkp)->lk_interlock); \ } while (/*CONSTCOND*/ 0) #ifdef DDB /* { */ #ifdef MULTIPROCESSOR int simple_lock_debugger = 1; /* more serious on MP */ #else int simple_lock_debugger = 0; #endif #define SLOCK_DEBUGGER() if (simple_lock_debugger) Debugger() #define SLOCK_TRACE() \ db_stack_trace_print((db_expr_t)__builtin_frame_address(0), \ TRUE, 65535, "", lock_printf); #else #define SLOCK_DEBUGGER() /* nothing */ #define SLOCK_TRACE() /* nothing */ #endif /* } */ /* * Acquire a resource. */ #define ACQUIRE(lkp, error, extflags, drain, wanted) \ do { \ for (error = 0; wanted; ) { \ if ((drain)) \ (lkp)->lk_flags |= LK_WAITDRAIN; \ else \ (lkp)->lk_waitcount++; \ /* XXX Cast away volatile. */ \ error = ltsleep((drain) ? \ (void *)&(lkp)->lk_flags : (void *)(lkp), \ (lkp)->lk_prio, (lkp)->lk_wmesg, (lkp)->lk_timo, \ &(lkp)->lk_interlock); \ if ((drain) == 0) \ (lkp)->lk_waitcount--; \ if (error) \ break; \ if ((extflags) & LK_SLEEPFAIL) { \ error = ENOLCK; \ break; \ } \ } \ } while (0) #define SETHOLDER(lkp, pid, cpu_id) \ (lkp)->lk_lockholder = (pid) #define WEHOLDIT(lkp, pid, cpu_id) \ (lkp)->lk_lockholder == (pid) #define WAKEUP_WAITER(lkp) \ do { \ if ((lkp)->lk_waitcount) { \ /* XXX Cast away volatile. */ \ wakeup((void *)(lkp)); \ } \ } while (/*CONSTCOND*/0) #if defined(LOCKDEBUG) /* { */ #if defined(MULTIPROCESSOR) /* { */ struct simplelock spinlock_list_slock = SIMPLELOCK_INITIALIZER; #define SPINLOCK_LIST_LOCK() \ __cpu_simple_lock(&spinlock_list_slock.lock_data) #define SPINLOCK_LIST_UNLOCK() \ __cpu_simple_unlock(&spinlock_list_slock.lock_data) #else #define SPINLOCK_LIST_LOCK() /* nothing */ #define SPINLOCK_LIST_UNLOCK() /* nothing */ #endif /* MULTIPROCESSOR */ /* } */ TAILQ_HEAD(, lock) spinlock_list = TAILQ_HEAD_INITIALIZER(spinlock_list); #endif /* LOCKDEBUG */ /* } */ #define HAVEIT(lkp) \ do { \ } while (/*CONSTCOND*/0) #define DONTHAVEIT(lkp) \ do { \ } while (/*CONSTCOND*/0) #if defined(LOCKDEBUG) /* * Lock debug printing routine; can be configured to print to console * or log to syslog. */ void lock_printf(const char *fmt, ...) { char b[150]; va_list ap; va_start(ap, fmt); if (lock_debug_syslog) vlog(LOG_DEBUG, fmt, ap); else { vsnprintf(b, sizeof(b), fmt, ap); printf_nolog("%s", b); } va_end(ap); } #endif /* LOCKDEBUG */ /* * Initialize a lock; required before use. */ void lockinit(struct lock *lkp, int prio, char *wmesg, int timo, int flags) { bzero(lkp, sizeof(struct lock)); simple_lock_init(&lkp->lk_interlock); lkp->lk_flags = flags & LK_EXTFLG_MASK; lkp->lk_lockholder = LK_NOPROC; lkp->lk_prio = prio; lkp->lk_timo = timo; lkp->lk_wmesg = wmesg; /* just a name for spin locks */ #if defined(LOCKDEBUG) lkp->lk_lock_file = NULL; lkp->lk_unlock_file = NULL; #endif } /* * Determine the status of a lock. */ int lockstatus(struct lock *lkp) { int lock_type = 0; INTERLOCK_ACQUIRE(lkp, lkp->lk_flags); if (lkp->lk_exclusivecount != 0) lock_type = LK_EXCLUSIVE; else if (lkp->lk_sharecount != 0) lock_type = LK_SHARED; INTERLOCK_RELEASE(lkp, lkp->lk_flags); return (lock_type); } /* * Set, change, or release a lock. * * Shared requests increment the shared count. Exclusive requests set the * LK_WANT_EXCL flag (preventing further shared locks), and wait for already * accepted shared locks and shared-to-exclusive upgrades to go away. */ int lockmgr(__volatile struct lock *lkp, u_int flags, struct simplelock *interlkp) { int error; pid_t pid; int extflags; cpuid_t cpu_id; struct proc *p = curproc; error = 0; INTERLOCK_ACQUIRE(lkp, lkp->lk_flags); if (flags & LK_INTERLOCK) simple_unlock(interlkp); extflags = (flags | lkp->lk_flags) & LK_EXTFLG_MASK; #ifdef DIAGNOSTIC if (p == NULL) panic("lockmgr: process context required"); #endif /* Process context required. */ pid = p->p_pid; cpu_id = CPU_NUMBER(); /* * Once a lock has drained, the LK_DRAINING flag is set and an * exclusive lock is returned. The only valid operation thereafter * is a single release of that exclusive lock. This final release * clears the LK_DRAINING flag and sets the LK_DRAINED flag. Any * further requests of any sort will result in a panic. The bits * selected for these two flags are chosen so that they will be set * in memory that is freed (freed memory is filled with 0xdeadbeef). */ if (lkp->lk_flags & (LK_DRAINING|LK_DRAINED)) { #ifdef DIAGNOSTIC if (lkp->lk_flags & LK_DRAINED) panic("lockmgr: using decommissioned lock"); if ((flags & LK_TYPE_MASK) != LK_RELEASE || WEHOLDIT(lkp, pid, cpu_id) == 0) panic("lockmgr: non-release on draining lock: %d", flags & LK_TYPE_MASK); #endif /* DIAGNOSTIC */ lkp->lk_flags &= ~LK_DRAINING; lkp->lk_flags |= LK_DRAINED; } /* * Check if the caller is asking us to be schizophrenic. */ if ((lkp->lk_flags & (LK_CANRECURSE|LK_RECURSEFAIL)) == (LK_CANRECURSE|LK_RECURSEFAIL)) panic("lockmgr: make up your mind"); switch (flags & LK_TYPE_MASK) { case LK_SHARED: if (WEHOLDIT(lkp, pid, cpu_id) == 0) { /* * If just polling, check to see if we will block. */ if ((extflags & LK_NOWAIT) && (lkp->lk_flags & (LK_HAVE_EXCL | LK_WANT_EXCL | LK_WANT_UPGRADE))) { error = EBUSY; break; } /* * Wait for exclusive locks and upgrades to clear. */ ACQUIRE(lkp, error, extflags, 0, lkp->lk_flags & (LK_HAVE_EXCL | LK_WANT_EXCL | LK_WANT_UPGRADE)); if (error) break; lkp->lk_sharecount++; COUNT(lkp, p, cpu_id, 1); break; } /* * We hold an exclusive lock, so downgrade it to shared. * An alternative would be to fail with EDEADLK. */ lkp->lk_sharecount++; COUNT(lkp, p, cpu_id, 1); /* FALLTHROUGH */ case LK_DOWNGRADE: if (WEHOLDIT(lkp, pid, cpu_id) == 0 || lkp->lk_exclusivecount == 0) panic("lockmgr: not holding exclusive lock"); lkp->lk_sharecount += lkp->lk_exclusivecount; lkp->lk_exclusivecount = 0; lkp->lk_flags &= ~LK_HAVE_EXCL; SETHOLDER(lkp, LK_NOPROC, LK_NOCPU); #if defined(LOCKDEBUG) lkp->lk_unlock_file = file; lkp->lk_unlock_line = line; #endif DONTHAVEIT(lkp); WAKEUP_WAITER(lkp); break; case LK_UPGRADE: /* * Upgrade a shared lock to an exclusive one. If another * shared lock has already requested an upgrade to an * exclusive lock, our shared lock is released and an * exclusive lock is requested (which will be granted * after the upgrade). If we return an error, the file * will always be unlocked. */ if (WEHOLDIT(lkp, pid, cpu_id) || lkp->lk_sharecount <= 0) panic("lockmgr: upgrade exclusive lock"); lkp->lk_sharecount--; COUNT(lkp, p, cpu_id, -1); /* * If we are just polling, check to see if we will block. */ if ((extflags & LK_NOWAIT) && ((lkp->lk_flags & LK_WANT_UPGRADE) || lkp->lk_sharecount > 1)) { error = EBUSY; break; } if ((lkp->lk_flags & LK_WANT_UPGRADE) == 0) { /* * We are first shared lock to request an upgrade, so * request upgrade and wait for the shared count to * drop to zero, then take exclusive lock. */ lkp->lk_flags |= LK_WANT_UPGRADE; ACQUIRE(lkp, error, extflags, 0, lkp->lk_sharecount); lkp->lk_flags &= ~LK_WANT_UPGRADE; if (error) break; lkp->lk_flags |= LK_HAVE_EXCL; SETHOLDER(lkp, pid, cpu_id); #if defined(LOCKDEBUG) lkp->lk_lock_file = file; lkp->lk_lock_line = line; #endif HAVEIT(lkp); if (lkp->lk_exclusivecount != 0) panic("lockmgr: non-zero exclusive count"); lkp->lk_exclusivecount = 1; COUNT(lkp, p, cpu_id, 1); break; } /* * Someone else has requested upgrade. Release our shared * lock, awaken upgrade requestor if we are the last shared * lock, then request an exclusive lock. */ if (lkp->lk_sharecount == 0) WAKEUP_WAITER(lkp); /* FALLTHROUGH */ case LK_EXCLUSIVE: if (WEHOLDIT(lkp, pid, cpu_id)) { /* * Recursive lock. */ if ((extflags & LK_CANRECURSE) == 0) { if (extflags & LK_RECURSEFAIL) { error = EDEADLK; break; } else panic("lockmgr: locking against myself"); } lkp->lk_exclusivecount++; COUNT(lkp, p, cpu_id, 1); break; } /* * If we are just polling, check to see if we will sleep. */ if ((extflags & LK_NOWAIT) && ((lkp->lk_flags & (LK_HAVE_EXCL | LK_WANT_EXCL | LK_WANT_UPGRADE)) || lkp->lk_sharecount != 0)) { error = EBUSY; break; } /* * Try to acquire the want_exclusive flag. */ ACQUIRE(lkp, error, extflags, 0, lkp->lk_flags & (LK_HAVE_EXCL | LK_WANT_EXCL)); if (error) break; lkp->lk_flags |= LK_WANT_EXCL; /* * Wait for shared locks and upgrades to finish. */ ACQUIRE(lkp, error, extflags, 0, lkp->lk_sharecount != 0 || (lkp->lk_flags & LK_WANT_UPGRADE)); lkp->lk_flags &= ~LK_WANT_EXCL; if (error) break; lkp->lk_flags |= LK_HAVE_EXCL; SETHOLDER(lkp, pid, cpu_id); #if defined(LOCKDEBUG) lkp->lk_lock_file = file; lkp->lk_lock_line = line; #endif HAVEIT(lkp); if (lkp->lk_exclusivecount != 0) panic("lockmgr: non-zero exclusive count"); lkp->lk_exclusivecount = 1; COUNT(lkp, p, cpu_id, 1); break; case LK_RELEASE: if (lkp->lk_exclusivecount != 0) { if (WEHOLDIT(lkp, pid, cpu_id) == 0) { panic("lockmgr: pid %d, not exclusive lock " "holder %d unlocking", pid, lkp->lk_lockholder); } lkp->lk_exclusivecount--; COUNT(lkp, p, cpu_id, -1); if (lkp->lk_exclusivecount == 0) { lkp->lk_flags &= ~LK_HAVE_EXCL; SETHOLDER(lkp, LK_NOPROC, LK_NOCPU); #if defined(LOCKDEBUG) lkp->lk_unlock_file = file; lkp->lk_unlock_line = line; #endif DONTHAVEIT(lkp); } } else if (lkp->lk_sharecount != 0) { lkp->lk_sharecount--; COUNT(lkp, p, cpu_id, -1); } #ifdef DIAGNOSTIC else panic("lockmgr: release of unlocked lock!"); #endif WAKEUP_WAITER(lkp); break; case LK_DRAIN: /* * Check that we do not already hold the lock, as it can * never drain if we do. Unfortunately, we have no way to * check for holding a shared lock, but at least we can * check for an exclusive one. */ if (WEHOLDIT(lkp, pid, cpu_id)) panic("lockmgr: draining against myself"); /* * If we are just polling, check to see if we will sleep. */ if ((extflags & LK_NOWAIT) && ((lkp->lk_flags & (LK_HAVE_EXCL | LK_WANT_EXCL | LK_WANT_UPGRADE)) || lkp->lk_sharecount != 0 || lkp->lk_waitcount != 0)) { error = EBUSY; break; } ACQUIRE(lkp, error, extflags, 1, ((lkp->lk_flags & (LK_HAVE_EXCL | LK_WANT_EXCL | LK_WANT_UPGRADE)) || lkp->lk_sharecount != 0 || lkp->lk_waitcount != 0)); if (error) break; lkp->lk_flags |= LK_DRAINING | LK_HAVE_EXCL; SETHOLDER(lkp, pid, cpu_id); #if defined(LOCKDEBUG) lkp->lk_lock_file = file; lkp->lk_lock_line = line; #endif HAVEIT(lkp); lkp->lk_exclusivecount = 1; COUNT(lkp, p, cpu_id, 1); break; default: INTERLOCK_RELEASE(lkp, lkp->lk_flags); panic("lockmgr: unknown locktype request %d", flags & LK_TYPE_MASK); /* NOTREACHED */ } if ((lkp->lk_flags & LK_WAITDRAIN) != 0 && ((lkp->lk_flags & (LK_HAVE_EXCL | LK_WANT_EXCL | LK_WANT_UPGRADE)) == 0 && lkp->lk_sharecount == 0 && lkp->lk_waitcount == 0)) { lkp->lk_flags &= ~LK_WAITDRAIN; wakeup((void *)&lkp->lk_flags); } INTERLOCK_RELEASE(lkp, lkp->lk_flags); return (error); } /* * Print out information about state of a lock. Used by VOP_PRINT * routines to display ststus about contained locks. */ void lockmgr_printinfo(__volatile struct lock *lkp) { if (lkp->lk_sharecount) printf(" lock type %s: SHARED (count %d)", lkp->lk_wmesg, lkp->lk_sharecount); else if (lkp->lk_flags & LK_HAVE_EXCL) { printf(" lock type %s: EXCL (count %d) by ", lkp->lk_wmesg, lkp->lk_exclusivecount); printf("pid %d", lkp->lk_lockholder); } else printf(" not locked"); if (lkp->lk_waitcount > 0) printf(" with %d pending", lkp->lk_waitcount); } #if defined(LOCKDEBUG) TAILQ_HEAD(, simplelock) simplelock_list = TAILQ_HEAD_INITIALIZER(simplelock_list); #if defined(MULTIPROCESSOR) /* { */ struct simplelock simplelock_list_slock = SIMPLELOCK_INITIALIZER; #define SLOCK_LIST_LOCK() \ __cpu_simple_lock(&simplelock_list_slock.lock_data) #define SLOCK_LIST_UNLOCK() \ __cpu_simple_unlock(&simplelock_list_slock.lock_data) #define SLOCK_COUNT(x) \ curcpu()->ci_simple_locks += (x) #else u_long simple_locks; #define SLOCK_LIST_LOCK() /* nothing */ #define SLOCK_LIST_UNLOCK() /* nothing */ #define SLOCK_COUNT(x) simple_locks += (x) #endif /* MULTIPROCESSOR */ /* } */ #ifdef MULTIPROCESSOR #define SLOCK_MP() lock_printf("on cpu %ld\n", \ (u_long) cpu_number()) #else #define SLOCK_MP() /* nothing */ #endif #define SLOCK_WHERE(str, alp, id, l) \ do { \ lock_printf("\n"); \ lock_printf(str); \ lock_printf("lock: %p, currently at: %s:%d\n", (alp), (id), (l)); \ SLOCK_MP(); \ if ((alp)->lock_file != NULL) \ lock_printf("last locked: %s:%d\n", (alp)->lock_file, \ (alp)->lock_line); \ if ((alp)->unlock_file != NULL) \ lock_printf("last unlocked: %s:%d\n", (alp)->unlock_file, \ (alp)->unlock_line); \ SLOCK_TRACE() \ SLOCK_DEBUGGER(); \ } while (/*CONSTCOND*/0) /* * Simple lock functions so that the debugger can see from whence * they are being called. */ void simple_lock_init(struct simplelock *lkp) { #if defined(MULTIPROCESSOR) /* { */ __cpu_simple_lock_init(&alp->lock_data); #else alp->lock_data = __SIMPLELOCK_UNLOCKED; #endif /* } */ alp->lock_file = NULL; alp->lock_line = 0; alp->unlock_file = NULL; alp->unlock_line = 0; alp->lock_holder = LK_NOCPU; } void _simple_lock(__volatile struct simplelock *lkp, const char *id, int l) { cpuid_t cpu_id = CPU_NUMBER(); int s; s = spllock(); /* * MULTIPROCESSOR case: This is `safe' since if it's not us, we * don't take any action, and just fall into the normal spin case. */ if (alp->lock_data == __SIMPLELOCK_LOCKED) { #if defined(MULTIPROCESSOR) /* { */ if (alp->lock_holder == cpu_id) { SLOCK_WHERE("simple_lock: locking against myself\n", alp, id, l); goto out; } #else SLOCK_WHERE("simple_lock: lock held\n", alp, id, l); goto out; #endif /* MULTIPROCESSOR */ /* } */ } #if defined(MULTIPROCESSOR) /* { */ /* Acquire the lock before modifying any fields. */ splx(s); __cpu_simple_lock(&alp->lock_data); s = spllock(); #else alp->lock_data = __SIMPLELOCK_LOCKED; #endif /* } */ if (alp->lock_holder != LK_NOCPU) { SLOCK_WHERE("simple_lock: uninitialized lock\n", alp, id, l); } alp->lock_file = id; alp->lock_line = l; alp->lock_holder = cpu_id; SLOCK_LIST_LOCK(); /* XXX Cast away volatile */ TAILQ_INSERT_TAIL(&simplelock_list, (struct simplelock *)alp, list); SLOCK_LIST_UNLOCK(); SLOCK_COUNT(1); out: splx(s); } int _simple_lock_held(__volatile struct simplelock *alp) { cpuid_t cpu_id = CPU_NUMBER(); int s, locked = 0; s = spllock(); #if defined(MULTIPROCESSOR) if (__cpu_simple_lock_try(&alp->lock_data) == 0) locked = (alp->lock_holder == cpu_id); else __cpu_simple_unlock(&alp->lock_data); #else if (alp->lock_data == __SIMPLELOCK_LOCKED) { locked = 1; KASSERT(alp->lock_holder == cpu_id); } #endif splx(s); return (locked); } int _simple_lock_try(__volatile struct simplelock *lkp, const char *id, int l) { cpuid_t cpu_id = CPU_NUMBER(); int s, rv = 0; s = spllock(); /* * MULTIPROCESSOR case: This is `safe' since if it's not us, we * don't take any action. */ #if defined(MULTIPROCESSOR) /* { */ if ((rv = __cpu_simple_lock_try(&alp->lock_data)) == 0) { if (alp->lock_holder == cpu_id) SLOCK_WHERE("simple_lock_try: locking against myself\n", alp, id, l); goto out; } #else if (alp->lock_data == __SIMPLELOCK_LOCKED) { SLOCK_WHERE("simple_lock_try: lock held\n", alp, id, l); goto out; } alp->lock_data = __SIMPLELOCK_LOCKED; #endif /* MULTIPROCESSOR */ /* } */ /* * At this point, we have acquired the lock. */ rv = 1; alp->lock_file = id; alp->lock_line = l; alp->lock_holder = cpu_id; SLOCK_LIST_LOCK(); /* XXX Cast away volatile. */ TAILQ_INSERT_TAIL(&simplelock_list, (struct simplelock *)alp, list); SLOCK_LIST_UNLOCK(); SLOCK_COUNT(1); out: splx(s); return (rv); } void _simple_unlock(__volatile struct simplelock *lkp, const char *id, int l) { int s; s = spllock(); /* * MULTIPROCESSOR case: This is `safe' because we think we hold * the lock, and if we don't, we don't take any action. */ if (alp->lock_data == __SIMPLELOCK_UNLOCKED) { SLOCK_WHERE("simple_unlock: lock not held\n", alp, id, l); goto out; } SLOCK_LIST_LOCK(); TAILQ_REMOVE(&simplelock_list, alp, list); SLOCK_LIST_UNLOCK(); SLOCK_COUNT(-1); alp->list.tqe_next = NULL; /* sanity */ alp->list.tqe_prev = NULL; /* sanity */ alp->unlock_file = id; alp->unlock_line = l; #if defined(MULTIPROCESSOR) /* { */ alp->lock_holder = LK_NOCPU; /* Now that we've modified all fields, release the lock. */ __cpu_simple_unlock(&alp->lock_data); #else alp->lock_data = __SIMPLELOCK_UNLOCKED; KASSERT(alp->lock_holder == CPU_NUMBER()); alp->lock_holder = LK_NOCPU; #endif /* } */ out: splx(s); } void simple_lock_dump(void) { struct simplelock *alp; int s; s = spllock(); SLOCK_LIST_LOCK(); lock_printf("all simple locks:\n"); TAILQ_FOREACH(alp, &simplelock_list, list) { lock_printf("%p CPU %lu %s:%d\n", alp, alp->lock_holder, alp->lock_file, alp->lock_line); } SLOCK_LIST_UNLOCK(); splx(s); } void simple_lock_freecheck(void *start, void *end) { struct simplelock *alp; int s; s = spllock(); SLOCK_LIST_LOCK(); TAILQ_FOREACH(alp, &simplelock_list, list) { if ((void *)alp >= start && (void *)alp < end) { lock_printf("freeing simple_lock %p CPU %lu %s:%d\n", alp, alp->lock_holder, alp->lock_file, alp->lock_line); SLOCK_DEBUGGER(); } } SLOCK_LIST_UNLOCK(); splx(s); } /* * We must be holding exactly one lock: the sched_lock. */ #ifdef notyet void simple_lock_switchcheck(void) { simple_lock_only_held(&sched_lock, "switching"); } #endif void simple_lock_only_held(volatile struct simplelock *lp, const char *where) { struct simplelock *alp; cpuid_t cpu_id = CPU_NUMBER(); int s; if (lp) { LOCK_ASSERT(simple_lock_held(lp)); } s = spllock(); SLOCK_LIST_LOCK(); TAILQ_FOREACH(alp, &simplelock_list, list) { if (alp == lp) continue; if (alp->lock_holder == cpu_id) break; } SLOCK_LIST_UNLOCK(); splx(s); if (alp != NULL) { lock_printf("\n%s with held simple_lock %p " "CPU %lu %s:%d\n", where, alp, alp->lock_holder, alp->lock_file, alp->lock_line); SLOCK_TRACE(); SLOCK_DEBUGGER(); } } #endif /* LOCKDEBUG */ #if defined(MULTIPROCESSOR) /* * Functions for manipulating the kernel_lock. We put them here * so that they show up in profiles. */ struct __mp_lock kernel_lock; void _kernel_lock_init(void) { __mp_lock_init(&kernel_lock); } /* * Acquire/release the kernel lock. Intended for use in the scheduler * and the lower half of the kernel. */ /* XXX The flag should go, all callers want equal behaviour. */ void _kernel_lock(int flag) { SCHED_ASSERT_UNLOCKED(); __mp_lock(&kernel_lock); } void _kernel_unlock(void) { __mp_unlock(&kernel_lock); } /* * Acquire/release the kernel_lock on behalf of a process. Intended for * use in the top half of the kernel. */ void _kernel_proc_lock(struct proc *p) { SCHED_ASSERT_UNLOCKED(); __mp_lock(&kernel_lock); atomic_setbits_int(&p->p_flag, P_BIGLOCK); } void _kernel_proc_unlock(struct proc *p) { atomic_clearbits_int(&p->p_flag, P_BIGLOCK); __mp_unlock(&kernel_lock); } #ifdef MP_LOCKDEBUG /* CPU-dependent timing, needs this to be settable from ddb. */ int __mp_lock_spinout = 200000000; #endif #endif /* MULTIPROCESSOR */