/*      $NetBSD: subr_lockdebug.c,v 1.83 2022/09/02 06:01:38 nakayama Exp $     */

/*-
 * Copyright (c) 2006, 2007, 2008, 2020 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Andrew Doran.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
 */

/*
 * Basic lock debugging code shared among lock primitives.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: subr_lockdebug.c,v 1.83 2022/09/02 06:01:38 nakayama Exp $");

#ifdef _KERNEL_OPT
#include "opt_ddb.h"
#endif

#include <sys/param.h>
#include <sys/proc.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/kmem.h>
#include <sys/lockdebug.h>
#include <sys/sleepq.h>
#include <sys/cpu.h>
#include <sys/atomic.h>
#include <sys/lock.h>
#include <sys/rbtree.h>
#include <sys/ksyms.h>
#include <sys/kcov.h>

#include <machine/lock.h>

#ifdef DDB
#include <machine/db_machdep.h>
#include <ddb/db_interface.h>
#include <ddb/db_access.h>
#include <ddb/db_sym.h>
#endif

unsigned int            ld_panic;

#ifdef LOCKDEBUG

#ifdef __ia64__
#define LD_BATCH_SHIFT  16
#else
#define LD_BATCH_SHIFT  9
#endif
#define LD_BATCH        (1 << LD_BATCH_SHIFT)
#define LD_BATCH_MASK   (LD_BATCH - 1)
#define LD_MAX_LOCKS    1048576
#define LD_SLOP         16

#define LD_LOCKED       0x01
#define LD_SLEEPER      0x02

#define LD_WRITE_LOCK   0x80000000

typedef struct lockdebug {
        struct rb_node  ld_rb_node;
        __cpu_simple_lock_t ld_spinlock;
        _TAILQ_ENTRY(struct lockdebug, volatile) ld_chain;
        _TAILQ_ENTRY(struct lockdebug, volatile) ld_achain;
        volatile void   *ld_lock;
        lockops_t       *ld_lockops;
        struct lwp      *ld_lwp;
        uintptr_t       ld_locked;
        uintptr_t       ld_unlocked;
        uintptr_t       ld_initaddr;
        uint16_t        ld_shares;
        uint16_t        ld_cpu;
        uint8_t         ld_flags;
        uint8_t         ld_shwant;      /* advisory */
        uint8_t         ld_exwant;      /* advisory */
        uint8_t         ld_unused;
} volatile lockdebug_t;

typedef _TAILQ_HEAD(lockdebuglist, struct lockdebug, volatile) lockdebuglist_t;

__cpu_simple_lock_t     ld_mod_lk;
lockdebuglist_t         ld_free = TAILQ_HEAD_INITIALIZER(ld_free);
#ifdef _KERNEL
lockdebuglist_t         ld_all = TAILQ_HEAD_INITIALIZER(ld_all);
#else
extern lockdebuglist_t  ld_all;
#define cpu_name(a)     "?"
#define cpu_index(a)    -1
#define curlwp          NULL
#endif /* _KERNEL */
int                     ld_nfree;
int                     ld_freeptr;
int                     ld_recurse;
bool                    ld_nomore;
lockdebug_t             ld_prime[LD_BATCH];

#ifdef _KERNEL
static void     lockdebug_abort1(const char *, size_t, lockdebug_t *, int,
    const char *, bool);
static int      lockdebug_more(int);
static void     lockdebug_init(void);
static void     lockdebug_dump(lwp_t *, lockdebug_t *,
    void (*)(const char *, ...)
    __printflike(1, 2));

static signed int
ld_rbto_compare_nodes(void *ctx, const void *n1, const void *n2)
{
        const lockdebug_t *ld1 = n1;
        const lockdebug_t *ld2 = n2;
        const uintptr_t a = (uintptr_t)ld1->ld_lock;
        const uintptr_t b = (uintptr_t)ld2->ld_lock;

        if (a < b)
                return -1;
        if (a > b)
                return 1;
        return 0;
}

static signed int
ld_rbto_compare_key(void *ctx, const void *n, const void *key)
{
        const lockdebug_t *ld = n;
        const uintptr_t a = (uintptr_t)ld->ld_lock;
        const uintptr_t b = (uintptr_t)key;

        if (a < b)
                return -1;
        if (a > b)
                return 1;
        return 0;
}

static rb_tree_t ld_rb_tree;

static const rb_tree_ops_t ld_rb_tree_ops = {
        .rbto_compare_nodes = ld_rbto_compare_nodes,
        .rbto_compare_key = ld_rbto_compare_key,
        .rbto_node_offset = offsetof(lockdebug_t, ld_rb_node),
        .rbto_context = NULL
};

static inline lockdebug_t *
lockdebug_lookup1(const volatile void *lock)
{
        lockdebug_t *ld;
        struct cpu_info *ci;

        ci = curcpu();
        __cpu_simple_lock(&ci->ci_data.cpu_ld_lock);
        ld = rb_tree_find_node(&ld_rb_tree, (void *)(intptr_t)lock);
        __cpu_simple_unlock(&ci->ci_data.cpu_ld_lock);
        if (ld == NULL) {
                return NULL;
        }
        __cpu_simple_lock(&ld->ld_spinlock);

        return ld;
}

static void
lockdebug_lock_cpus(void)
{
        CPU_INFO_ITERATOR cii;
        struct cpu_info *ci;

        for (CPU_INFO_FOREACH(cii, ci)) {
                __cpu_simple_lock(&ci->ci_data.cpu_ld_lock);
        }
}

static void
lockdebug_unlock_cpus(void)
{
        CPU_INFO_ITERATOR cii;
        struct cpu_info *ci;

        for (CPU_INFO_FOREACH(cii, ci)) {
                __cpu_simple_unlock(&ci->ci_data.cpu_ld_lock);
        }
}

/*
 * lockdebug_lookup:
 *
 *      Find a lockdebug structure by a pointer to a lock and return it locked.
 */
static inline lockdebug_t *
lockdebug_lookup(const char *func, size_t line, const volatile void *lock,
    uintptr_t where)
{
        lockdebug_t *ld;

        kcov_silence_enter();
        ld = lockdebug_lookup1(lock);
        kcov_silence_leave();

        if (__predict_false(ld == NULL)) {
                panic("%s,%zu: uninitialized lock (lock=%p, from=%08"
                    PRIxPTR ")", func, line, lock, where);
        }
        return ld;
}

/*
 * lockdebug_init:
 *
 *      Initialize the lockdebug system.  Allocate an initial pool of
 *      lockdebug structures before the VM system is up and running.
 */
static void
lockdebug_init(void)
{
        lockdebug_t *ld;
        int i;

        TAILQ_INIT(&curcpu()->ci_data.cpu_ld_locks);
        TAILQ_INIT(&curlwp->l_ld_locks);
        __cpu_simple_lock_init(&curcpu()->ci_data.cpu_ld_lock);
        __cpu_simple_lock_init(&ld_mod_lk);

        rb_tree_init(&ld_rb_tree, &ld_rb_tree_ops);

        ld = ld_prime;
        for (i = 1, ld++; i < LD_BATCH; i++, ld++) {
                __cpu_simple_lock_init(&ld->ld_spinlock);
                TAILQ_INSERT_TAIL(&ld_free, ld, ld_chain);
                TAILQ_INSERT_TAIL(&ld_all, ld, ld_achain);
        }
        ld_freeptr = 1;
        ld_nfree = LD_BATCH - 1;
}

/*
 * lockdebug_alloc:
 *
 *      A lock is being initialized, so allocate an associated debug
 *      structure.
 */
bool
lockdebug_alloc(const char *func, size_t line, volatile void *lock,
    lockops_t *lo, uintptr_t initaddr)
{
        struct cpu_info *ci;
        lockdebug_t *ld;
        int s;

        if (__predict_false(lo == NULL || panicstr != NULL || ld_panic))
                return false;
        if (__predict_false(ld_freeptr == 0))
                lockdebug_init();

        s = splhigh();
        __cpu_simple_lock(&ld_mod_lk);
        if (__predict_false((ld = lockdebug_lookup1(lock)) != NULL)) {
                __cpu_simple_unlock(&ld_mod_lk);
                lockdebug_abort1(func, line, ld, s, "already initialized",
                    true);
                return false;
        }

        /*
         * Pinch a new debug structure.  We may recurse because we call
         * kmem_alloc(), which may need to initialize new locks somewhere
         * down the path.  If not recursing, we try to maintain at least
         * LD_SLOP structures free, which should hopefully be enough to
         * satisfy kmem_alloc().  If we can't provide a structure, not to
         * worry: we'll just mark the lock as not having an ID.
         */
        ci = curcpu();
        ci->ci_lkdebug_recurse++;
        if (TAILQ_EMPTY(&ld_free)) {
                if (ci->ci_lkdebug_recurse > 1 || ld_nomore) {
                        ci->ci_lkdebug_recurse--;
                        __cpu_simple_unlock(&ld_mod_lk);
                        splx(s);
                        return false;
                }
                s = lockdebug_more(s);
        } else if (ci->ci_lkdebug_recurse == 1 && ld_nfree < LD_SLOP) {
                s = lockdebug_more(s);
        }
        if (__predict_false((ld = TAILQ_FIRST(&ld_free)) == NULL)) {
                __cpu_simple_unlock(&ld_mod_lk);
                splx(s);
                return false;
        }
        TAILQ_REMOVE(&ld_free, ld, ld_chain);
        ld_nfree--;
        ci->ci_lkdebug_recurse--;

        if (__predict_false(ld->ld_lock != NULL)) {
                panic("%s,%zu: corrupt table ld %p", func, line, ld);
        }

        /* Initialise the structure. */
        ld->ld_lock = lock;
        ld->ld_lockops = lo;
        ld->ld_locked = 0;
        ld->ld_unlocked = 0;
        ld->ld_lwp = NULL;
        ld->ld_initaddr = initaddr;
        ld->ld_flags = (lo->lo_type == LOCKOPS_SLEEP ? LD_SLEEPER : 0);
        lockdebug_lock_cpus();
        (void)rb_tree_insert_node(&ld_rb_tree, __UNVOLATILE(ld));
        lockdebug_unlock_cpus();
        __cpu_simple_unlock(&ld_mod_lk);

        splx(s);
        return true;
}

/*
 * lockdebug_free:
 *
 *      A lock is being destroyed, so release debugging resources.
 */
void
lockdebug_free(const char *func, size_t line, volatile void *lock)
{
        lockdebug_t *ld;
        int s;

        if (__predict_false(panicstr != NULL || ld_panic))
                return;

        s = splhigh();
        __cpu_simple_lock(&ld_mod_lk);
        ld = lockdebug_lookup(func, line, lock,
            (uintptr_t) __builtin_return_address(0));
        if (__predict_false(ld == NULL)) {
                __cpu_simple_unlock(&ld_mod_lk);
                panic("%s,%zu: destroying uninitialized object %p"
                    "(ld_lock=%p)", func, line, lock, ld->ld_lock);
                return;
        }
        if (__predict_false((ld->ld_flags & LD_LOCKED) != 0 ||
            ld->ld_shares != 0)) {
                __cpu_simple_unlock(&ld_mod_lk);
                lockdebug_abort1(func, line, ld, s, "is locked or in use",
                    true);
                return;
        }
        lockdebug_lock_cpus();
        rb_tree_remove_node(&ld_rb_tree, __UNVOLATILE(ld));
        lockdebug_unlock_cpus();
        ld->ld_lock = NULL;
        TAILQ_INSERT_TAIL(&ld_free, ld, ld_chain);
        ld_nfree++;
        __cpu_simple_unlock(&ld->ld_spinlock);
        __cpu_simple_unlock(&ld_mod_lk);
        splx(s);
}

/*
 * lockdebug_more:
 *
 *      Allocate a batch of debug structures and add to the free list.
 *      Must be called with ld_mod_lk held.
 */
static int
lockdebug_more(int s)
{
        lockdebug_t *ld;
        void *block;
        int i, base, m;

        /*
         * Can't call kmem_alloc() if in interrupt context.  XXX We could
         * deadlock, because we don't know which locks the caller holds.
         */
        if (cpu_intr_p() || cpu_softintr_p()) {
                return s;
        }

        while (ld_nfree < LD_SLOP) {
                __cpu_simple_unlock(&ld_mod_lk);
                splx(s);
                block = kmem_zalloc(LD_BATCH * sizeof(lockdebug_t), KM_SLEEP);
                s = splhigh();
                __cpu_simple_lock(&ld_mod_lk);

                if (ld_nfree > LD_SLOP) {
                        /* Somebody beat us to it. */
                        __cpu_simple_unlock(&ld_mod_lk);
                        splx(s);
                        kmem_free(block, LD_BATCH * sizeof(lockdebug_t));
                        s = splhigh();
                        __cpu_simple_lock(&ld_mod_lk);
                        continue;
                }

                base = ld_freeptr;
                ld_nfree += LD_BATCH;
                ld = block;
                base <<= LD_BATCH_SHIFT;
                m = uimin(LD_MAX_LOCKS, base + LD_BATCH);

                if (m == LD_MAX_LOCKS)
                        ld_nomore = true;

                for (i = base; i < m; i++, ld++) {
                        __cpu_simple_lock_init(&ld->ld_spinlock);
                        TAILQ_INSERT_TAIL(&ld_free, ld, ld_chain);
                        TAILQ_INSERT_TAIL(&ld_all, ld, ld_achain);
                }

                membar_producer();
        }

        return s;
}

/*
 * lockdebug_wantlock:
 *
 *      Process the preamble to a lock acquire.  The "shared"
 *      parameter controls which ld_{ex,sh}want counter is
 *      updated; a negative value of shared updates neither.
 */
void
lockdebug_wantlock(const char *func, size_t line,
    const volatile void *lock, uintptr_t where, int shared)
{
        struct lwp *l = curlwp;
        lockdebug_t *ld;
        bool recurse;
        int s;

        (void)shared;
        recurse = false;

        if (__predict_false(panicstr != NULL || ld_panic))
                return;

        s = splhigh();
        if ((ld = lockdebug_lookup(func, line, lock, where)) == NULL) {
                splx(s);
                return;
        }
        if ((ld->ld_flags & LD_LOCKED) != 0 || ld->ld_shares != 0) {
                if ((ld->ld_flags & LD_SLEEPER) != 0) {
                        if (ld->ld_lwp == l)
                                recurse = true;
                } else if (ld->ld_cpu == (uint16_t)cpu_index(curcpu()))
                        recurse = true;
        }
        if (cpu_intr_p()) {
                if (__predict_false((ld->ld_flags & LD_SLEEPER) != 0)) {
                        lockdebug_abort1(func, line, ld, s,
                            "acquiring sleep lock from interrupt context",
                            true);
                        return;
                }
        }
        if (shared > 0)
                ld->ld_shwant++;
        else if (shared == 0)
                ld->ld_exwant++;
        if (__predict_false(recurse)) {
                lockdebug_abort1(func, line, ld, s, "locking against myself",
                    true);
                return;
        }
        if (l->l_ld_wanted == NULL) {
                l->l_ld_wanted = ld;
        }
        __cpu_simple_unlock(&ld->ld_spinlock);
        splx(s);
}

/*
 * lockdebug_locked:
 *
 *      Process a lock acquire operation.
 */
void
lockdebug_locked(const char *func, size_t line,
    volatile void *lock, void *cvlock, uintptr_t where, int shared)
{
        struct lwp *l = curlwp;
        lockdebug_t *ld;
        int s;

        if (__predict_false(panicstr != NULL || ld_panic))
                return;

        s = splhigh();
        if ((ld = lockdebug_lookup(func, line, lock, where)) == NULL) {
                splx(s);
                return;
        }
        if (shared) {
                l->l_shlocks++;
                ld->ld_locked = where;
                ld->ld_shares++;
                ld->ld_shwant--;
        } else {
                if (__predict_false((ld->ld_flags & LD_LOCKED) != 0)) {
                        lockdebug_abort1(func, line, ld, s, "already locked",
                            true);
                        return;
                }
                ld->ld_flags |= LD_LOCKED;
                ld->ld_locked = where;
                ld->ld_exwant--;
                if ((ld->ld_flags & LD_SLEEPER) != 0) {
                        TAILQ_INSERT_TAIL(&l->l_ld_locks, ld, ld_chain);
                } else {
                        TAILQ_INSERT_TAIL(&curcpu()->ci_data.cpu_ld_locks,
                            ld, ld_chain);
                }
        }
        ld->ld_cpu = (uint16_t)cpu_index(curcpu());
        ld->ld_lwp = l;
        __cpu_simple_unlock(&ld->ld_spinlock);
        if (l->l_ld_wanted == ld) {
                l->l_ld_wanted = NULL;
        }
        splx(s);
}

/*
 * lockdebug_unlocked:
 *
 *      Process a lock release operation.
 */
void
lockdebug_unlocked(const char *func, size_t line,
    volatile void *lock, uintptr_t where, int shared)
{
        struct lwp *l = curlwp;
        lockdebug_t *ld;
        int s;

        if (__predict_false(panicstr != NULL || ld_panic))
                return;

        s = splhigh();
        if ((ld = lockdebug_lookup(func, line, lock, where)) == NULL) {
                splx(s);
                return;
        }
        if (shared) {
                if (__predict_false(l->l_shlocks == 0)) {
                        lockdebug_abort1(func, line, ld, s,
                            "no shared locks held by LWP", true);
                        return;
                }
                if (__predict_false(ld->ld_shares == 0)) {
                        lockdebug_abort1(func, line, ld, s,
                            "no shared holds on this lock", true);
                        return;
                }
                l->l_shlocks--;
                ld->ld_shares--;
                if (ld->ld_lwp == l) {
                        ld->ld_unlocked = where;
                        ld->ld_lwp = NULL;
                }
                if (ld->ld_cpu == (uint16_t)cpu_index(curcpu()))
                        ld->ld_cpu = (uint16_t)-1;
        } else {
                if (__predict_false((ld->ld_flags & LD_LOCKED) == 0)) {
                        lockdebug_abort1(func, line, ld, s, "not locked", true);
                        return;
                }

                if ((ld->ld_flags & LD_SLEEPER) != 0) {
                        if (__predict_false(ld->ld_lwp != curlwp)) {
                                lockdebug_abort1(func, line, ld, s,
                                    "not held by current LWP", true);
                                return;
                        }
                        TAILQ_REMOVE(&l->l_ld_locks, ld, ld_chain);
                } else {
                        uint16_t idx = (uint16_t)cpu_index(curcpu());
                        if (__predict_false(ld->ld_cpu != idx)) {
                                lockdebug_abort1(func, line, ld, s,
                                    "not held by current CPU", true);
                                return;
                        }
                        TAILQ_REMOVE(&curcpu()->ci_data.cpu_ld_locks, ld,
                            ld_chain);
                }
                ld->ld_flags &= ~LD_LOCKED;
                ld->ld_unlocked = where;
                ld->ld_lwp = NULL;
        }
        __cpu_simple_unlock(&ld->ld_spinlock);
        splx(s);
}

/*
 * lockdebug_barrier:
 *
 *      Panic if we hold more than one specified lock, and optionally, if we
 *      hold any sleep locks.
 */
void
lockdebug_barrier(const char *func, size_t line, volatile void *onelock,
    int slplocks)
{
        struct lwp *l = curlwp;
        lockdebug_t *ld;
        int s;

        if (__predict_false(panicstr != NULL || ld_panic))
                return;

        s = splhigh();
        if ((l->l_pflag & LP_INTR) == 0) {
                TAILQ_FOREACH(ld, &curcpu()->ci_data.cpu_ld_locks, ld_chain) {
                        if (ld->ld_lock == onelock) {
                                continue;
                        }
                        __cpu_simple_lock(&ld->ld_spinlock);
                        lockdebug_abort1(func, line, ld, s,
                            "spin lock held", true);
                        return;
                }
        }
        if (slplocks) {
                splx(s);
                return;
        }
        ld = TAILQ_FIRST(&l->l_ld_locks);
        if (__predict_false(ld != NULL && ld->ld_lock != onelock)) {
                __cpu_simple_lock(&ld->ld_spinlock);
                lockdebug_abort1(func, line, ld, s, "sleep lock held", true);
                return;
        }
        splx(s);
        if (l->l_shlocks != 0) {
                TAILQ_FOREACH(ld, &ld_all, ld_achain) {
                        if (ld->ld_lock == onelock) {
                                continue;
                        }
                        if (ld->ld_lwp == l)
                                lockdebug_dump(l, ld, printf);
                }
                panic("%s,%zu: holding %d shared locks", func, line,
                    l->l_shlocks);
        }
}

/*
 * lockdebug_mem_check:
 *
 *      Check for in-use locks within a memory region that is
 *      being freed.
 */
void
lockdebug_mem_check(const char *func, size_t line, void *base, size_t sz)
{
        lockdebug_t *ld;
        struct cpu_info *ci;
        int s;

        if (__predict_false(panicstr != NULL || ld_panic))
                return;

        kcov_silence_enter();

        s = splhigh();
        ci = curcpu();
        __cpu_simple_lock(&ci->ci_data.cpu_ld_lock);
        ld = (lockdebug_t *)rb_tree_find_node_geq(&ld_rb_tree, base);
        if (ld != NULL) {
                const uintptr_t lock = (uintptr_t)ld->ld_lock;

                if (__predict_false((uintptr_t)base > lock))
                        panic("%s,%zu: corrupt tree ld=%p, base=%p, sz=%zu",
                            func, line, ld, base, sz);
                if (lock >= (uintptr_t)base + sz)
                        ld = NULL;
        }
        __cpu_simple_unlock(&ci->ci_data.cpu_ld_lock);
        if (__predict_false(ld != NULL)) {
                __cpu_simple_lock(&ld->ld_spinlock);
                lockdebug_abort1(func, line, ld, s,
                    "allocation contains active lock", !cold);
                kcov_silence_leave();
                return;
        }
        splx(s);

        kcov_silence_leave();
}
#endif /* _KERNEL */

/*
 * lockdebug_dump:
 *
 *      Dump information about a lock on panic, or for DDB.
 */
static void
lockdebug_dump(lwp_t *l, lockdebug_t *ld, void (*pr)(const char *, ...)
    __printflike(1, 2))
{
        int sleeper = (ld->ld_flags & LD_SLEEPER);
        lockops_t *lo = ld->ld_lockops;
        char locksym[128], initsym[128], lockedsym[128], unlockedsym[128];

#ifdef DDB
        db_symstr(locksym, sizeof(locksym), (db_expr_t)(intptr_t)ld->ld_lock,
            DB_STGY_ANY);
        db_symstr(initsym, sizeof(initsym), (db_expr_t)ld->ld_initaddr,
            DB_STGY_PROC);
        db_symstr(lockedsym, sizeof(lockedsym), (db_expr_t)ld->ld_locked,
            DB_STGY_PROC);
        db_symstr(unlockedsym, sizeof(unlockedsym), (db_expr_t)ld->ld_unlocked,
            DB_STGY_PROC);
#else
        snprintf(locksym, sizeof(locksym), "%#018lx",
            (unsigned long)ld->ld_lock);
        snprintf(initsym, sizeof(initsym), "%#018lx",
            (unsigned long)ld->ld_initaddr);
        snprintf(lockedsym, sizeof(lockedsym), "%#018lx",
            (unsigned long)ld->ld_locked);
        snprintf(unlockedsym, sizeof(unlockedsym), "%#018lx",
            (unsigned long)ld->ld_unlocked);
#endif

        (*pr)(
            "lock address : %s\n"
            "type         : %s\n"
            "initialized  : %s",
            locksym, (sleeper ? "sleep/adaptive" : "spin"),
            initsym);

#ifndef _KERNEL
        lockops_t los;
        lo = &los;
        db_read_bytes((db_addr_t)ld->ld_lockops, sizeof(los), (char *)lo);
#endif
        (*pr)("\n"
            "shared holds : %18u exclusive: %18u\n"
            "shares wanted: %18u exclusive: %18u\n"
            "relevant cpu : %18u last held: %18u\n"
            "relevant lwp : %#018lx last held: %#018lx\n"
            "last locked%c : %s\n"
            "unlocked%c    : %s\n",
            (unsigned)ld->ld_shares, ((ld->ld_flags & LD_LOCKED) != 0),
            (unsigned)ld->ld_shwant, (unsigned)ld->ld_exwant,
            (unsigned)cpu_index(l->l_cpu), (unsigned)ld->ld_cpu,
            (long)l, (long)ld->ld_lwp,
            ((ld->ld_flags & LD_LOCKED) ? '*' : ' '),
            lockedsym,
            ((ld->ld_flags & LD_LOCKED) ? ' ' : '*'),
            unlockedsym);

#ifdef _KERNEL
        if (lo->lo_dump != NULL)
                (*lo->lo_dump)(ld->ld_lock, pr);

        if (sleeper) {
                turnstile_print(ld->ld_lock, pr);
        }
#endif
}

#ifdef _KERNEL
/*
 * lockdebug_abort1:
 *
 *      An error has been trapped - dump lock info and panic.
 */
static void
lockdebug_abort1(const char *func, size_t line, lockdebug_t *ld, int s,
                 const char *msg, bool dopanic)
{

        /*
         * Don't make the situation worse if the system is already going
         * down in flames.  Once a panic is triggered, lockdebug state
         * becomes stale and cannot be trusted.
         */
        if (atomic_inc_uint_nv(&ld_panic) != 1) {
                __cpu_simple_unlock(&ld->ld_spinlock);
                splx(s);
                return;
        }

        printf("%s error: %s,%zu: %s\n\n", ld->ld_lockops->lo_name,
            func, line, msg);
        lockdebug_dump(curlwp, ld, printf);
        __cpu_simple_unlock(&ld->ld_spinlock);
        splx(s);
        printf("\n");
        if (dopanic)
                panic("LOCKDEBUG: %s error: %s,%zu: %s",
                    ld->ld_lockops->lo_name, func, line, msg);
}

#endif /* _KERNEL */
#endif  /* LOCKDEBUG */

/*
 * lockdebug_lock_print:
 *
 *      Handle the DDB 'show lock' command.
 */
#ifdef DDB
void
lockdebug_lock_print(void *addr,
    void (*pr)(const char *, ...) __printflike(1, 2))
{
#ifdef LOCKDEBUG
        lockdebug_t *ld, lds;

        TAILQ_FOREACH(ld, &ld_all, ld_achain) {
                db_read_bytes((db_addr_t)ld, sizeof(lds), __UNVOLATILE(&lds));
                ld = &lds;
                if (ld->ld_lock == NULL)
                        continue;
                if (addr == NULL || ld->ld_lock == addr) {
                        lockdebug_dump(curlwp, ld, pr);
                        if (addr != NULL)
                                return;
                }
        }
        if (addr != NULL) {
                (*pr)("Sorry, no record of a lock with address %p found.\n",
                    addr);
        }
#else
        char sym[128];
        uintptr_t word;

        (*pr)("WARNING: lock print is unreliable without LOCKDEBUG\n");
        db_symstr(sym, sizeof(sym), (db_expr_t)(intptr_t)addr, DB_STGY_ANY);
        db_read_bytes((db_addr_t)addr, sizeof(word), (char *)&word);
        (*pr)("%s: possible owner: %p, bits: 0x%" PRIxPTR "\n", sym,
            (void *)(word & ~(uintptr_t)ALIGNBYTES), word & ALIGNBYTES);
#endif  /* LOCKDEBUG */
}

#ifdef _KERNEL
#ifdef LOCKDEBUG
static void
lockdebug_show_one(lwp_t *l, lockdebug_t *ld, int i,
    void (*pr)(const char *, ...) __printflike(1, 2))
{
        char sym[128];

#ifdef DDB
        db_symstr(sym, sizeof(sym), (db_expr_t)ld->ld_initaddr, DB_STGY_PROC);
#else
        snprintf(sym, sizeof(sym), "%p", (void *)ld->ld_initaddr);
#endif
        (*pr)("* Lock %d (initialized at %s)\n", i++, sym);
        lockdebug_dump(l, ld, pr);
}

static void
lockdebug_show_trace(const void *ptr,
    void (*pr)(const char *, ...) __printflike(1, 2))
{

        db_stack_trace_print((db_expr_t)(intptr_t)ptr, true, 32, "a", pr);
}

static void
lockdebug_show_all_locks_lwp(void (*pr)(const char *, ...) __printflike(1, 2),
    bool show_trace)
{
        struct proc *p;

        LIST_FOREACH(p, &allproc, p_list) {
                struct lwp *l;
                LIST_FOREACH(l, &p->p_lwps, l_sibling) {
                        lockdebug_t *ld;
                        int i = 0;
                        if (TAILQ_EMPTY(&l->l_ld_locks) &&
                            l->l_ld_wanted == NULL) {
                                continue;
                        }
                        (*pr)("\n****** LWP %d.%d (%s) @ %p, l_stat=%d\n",
                            p->p_pid, l->l_lid,
                            l->l_name ? l->l_name : p->p_comm, l, l->l_stat);
                        if (!TAILQ_EMPTY(&l->l_ld_locks)) {
                                (*pr)("\n*** Locks held: \n");
                                TAILQ_FOREACH(ld, &l->l_ld_locks, ld_chain) {
                                        (*pr)("\n");
                                        lockdebug_show_one(l, ld, i++, pr);
                                }
                        } else {
                                (*pr)("\n*** Locks held: none\n");
                        }

                        if (l->l_ld_wanted != NULL) {
                                (*pr)("\n*** Locks wanted: \n\n");
                                lockdebug_show_one(l, l->l_ld_wanted, 0, pr);
                        } else {
                                (*pr)("\n*** Locks wanted: none\n");
                        }
                        if (show_trace) {
                                (*pr)("\n*** Traceback: \n\n");
                                lockdebug_show_trace(l, pr);
                                (*pr)("\n");
                        }
                }
        }
}

static void
lockdebug_show_all_locks_cpu(void (*pr)(const char *, ...) __printflike(1, 2),
    bool show_trace)
{
        lockdebug_t *ld;
        CPU_INFO_ITERATOR cii;
        struct cpu_info *ci;

        for (CPU_INFO_FOREACH(cii, ci)) {
                int i = 0;
                if (TAILQ_EMPTY(&ci->ci_data.cpu_ld_locks))
                        continue;
                (*pr)("\n******* Locks held on %s:\n", cpu_name(ci));
                TAILQ_FOREACH(ld, &ci->ci_data.cpu_ld_locks, ld_chain) {
                        (*pr)("\n");
#ifdef MULTIPROCESSOR
                        lockdebug_show_one(ci->ci_curlwp, ld, i++, pr);
                        if (show_trace)
                                lockdebug_show_trace(ci->ci_curlwp, pr);
#else
                        lockdebug_show_one(curlwp, ld, i++, pr);
                        if (show_trace)
                                lockdebug_show_trace(curlwp, pr);
#endif
                }
        }
}
#endif /* _KERNEL */
#endif  /* LOCKDEBUG */

#ifdef _KERNEL
void
lockdebug_show_all_locks(void (*pr)(const char *, ...) __printflike(1, 2),
    const char *modif)
{
#ifdef LOCKDEBUG
        bool show_trace = false;
        if (modif[0] == 't')
                show_trace = true;

        (*pr)("[Locks tracked through LWPs]\n");
        lockdebug_show_all_locks_lwp(pr, show_trace);
        (*pr)("\n");

        (*pr)("[Locks tracked through CPUs]\n");
        lockdebug_show_all_locks_cpu(pr, show_trace);
        (*pr)("\n");
#else
        (*pr)("Sorry, kernel not built with the LOCKDEBUG option.\n");
#endif  /* LOCKDEBUG */
}

void
lockdebug_show_lockstats(void (*pr)(const char *, ...) __printflike(1, 2))
{
#ifdef LOCKDEBUG
        lockdebug_t *ld;
        void *_ld;
        uint32_t n_null = 0;
        uint32_t n_spin_mutex = 0;
        uint32_t n_adaptive_mutex = 0;
        uint32_t n_rwlock = 0;
        uint32_t n_others = 0;

        RB_TREE_FOREACH(_ld, &ld_rb_tree) {
                ld = _ld;
                if (ld->ld_lock == NULL) {
                        n_null++;
                        continue;
                }
                if (ld->ld_lockops->lo_name[0] == 'M') {
                        if (ld->ld_lockops->lo_type == LOCKOPS_SLEEP)
                                n_adaptive_mutex++;
                        else
                                n_spin_mutex++;
                        continue;
                }
                if (ld->ld_lockops->lo_name[0] == 'R') {
                        n_rwlock++;
                        continue;
                }
                n_others++;
        }
        (*pr)(
            "spin mutex: %u\n"
            "adaptive mutex: %u\n"
            "rwlock: %u\n"
            "null locks: %u\n"
            "others: %u\n",
            n_spin_mutex, n_adaptive_mutex, n_rwlock,
            n_null, n_others);
#else
        (*pr)("Sorry, kernel not built with the LOCKDEBUG option.\n");
#endif  /* LOCKDEBUG */
}
#endif /* _KERNEL */
#endif  /* DDB */

#ifdef _KERNEL
/*
 * lockdebug_dismiss:
 *
 *      The system is rebooting, and potentially from an unsafe
 *      place so avoid any future aborts.
 */
void
lockdebug_dismiss(void)
{

        atomic_inc_uint_nv(&ld_panic);
}

/*
 * lockdebug_abort:
 *
 *      An error has been trapped - dump lock info and call panic().
 */
void
lockdebug_abort(const char *func, size_t line, const volatile void *lock,
    lockops_t *ops, const char *msg)
{
#ifdef LOCKDEBUG
        lockdebug_t *ld;
        int s;

        s = splhigh();
        if ((ld = lockdebug_lookup(func, line, lock,
                        (uintptr_t) __builtin_return_address(0))) != NULL) {
                lockdebug_abort1(func, line, ld, s, msg, true);
                return;
        }
        splx(s);
#endif  /* LOCKDEBUG */

        /*
         * Don't make the situation worse if the system is already going
         * down in flames.  Once a panic is triggered, lockdebug state
         * becomes stale and cannot be trusted.
         */
        if (atomic_inc_uint_nv(&ld_panic) > 1)
                return;

        char locksym[128];

#ifdef DDB
        db_symstr(locksym, sizeof(locksym), (db_expr_t)(intptr_t)lock,
            DB_STGY_ANY);
#else
        snprintf(locksym, sizeof(locksym), "%#018lx", (unsigned long)lock);
#endif

        printf("%s error: %s,%zu: %s\n\n"
            "lock address : %s\n"
            "current cpu  : %18d\n"
            "current lwp  : %#018lx\n",
            ops->lo_name, func, line, msg, locksym,
            (int)cpu_index(curcpu()), (long)curlwp);
        (*ops->lo_dump)(lock, printf);
        printf("\n");

        panic("lock error: %s: %s,%zu: %s: lock %p cpu %d lwp %p",
            ops->lo_name, func, line, msg, lock, cpu_index(curcpu()), curlwp);
}
#endif /* _KERNEL */