/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1982, 1986, 1991, 1993
 *      The Regents of the University of California.  All rights reserved.
 * (c) UNIX System Laboratories, Inc.
 * All or some portions of this file are derived from material licensed
 * to the University of California by American Telephone and Telegraph
 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
 * the permission of UNIX System Laboratories, Inc.
 *
 * 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.
 */

#include <sys/cdefs.h>
#include "opt_kdb.h"
#include "opt_device_polling.h"
#include "opt_hwpmc_hooks.h"
#include "opt_ntp.h"
#include "opt_watchdog.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/callout.h>
#include <sys/epoch.h>
#include <sys/eventhandler.h>
#include <sys/gtaskqueue.h>
#include <sys/kdb.h>
#include <sys/kernel.h>
#include <sys/kthread.h>
#include <sys/ktr.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/resource.h>
#include <sys/resourcevar.h>
#include <sys/sched.h>
#include <sys/sdt.h>
#include <sys/signalvar.h>
#include <sys/sleepqueue.h>
#include <sys/smp.h>
#include <vm/vm.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>
#include <sys/sysctl.h>
#include <sys/bus.h>
#include <sys/interrupt.h>
#include <sys/limits.h>
#include <sys/timetc.h>

#ifdef HWPMC_HOOKS
#include <sys/pmckern.h>
PMC_SOFT_DEFINE( , , clock, hard);
PMC_SOFT_DEFINE( , , clock, stat);
PMC_SOFT_DEFINE_EX( , , clock, prof, \
    cpu_startprofclock, cpu_stopprofclock);
#endif

#ifdef DEVICE_POLLING
extern void hardclock_device_poll(void);
#endif /* DEVICE_POLLING */

/* Spin-lock protecting profiling statistics. */
static struct mtx time_lock;

SDT_PROVIDER_DECLARE(sched);
SDT_PROBE_DEFINE2(sched, , , tick, "struct thread *", "struct proc *");

static int
sysctl_kern_cp_time(SYSCTL_HANDLER_ARGS)
{
        int error;
        long cp_time[CPUSTATES];
#ifdef SCTL_MASK32
        int i;
        unsigned int cp_time32[CPUSTATES];
#endif

        read_cpu_time(cp_time);
#ifdef SCTL_MASK32
        if (req->flags & SCTL_MASK32) {
                if (!req->oldptr)
                        return SYSCTL_OUT(req, 0, sizeof(cp_time32));
                for (i = 0; i < CPUSTATES; i++)
                        cp_time32[i] = (unsigned int)cp_time[i];
                error = SYSCTL_OUT(req, cp_time32, sizeof(cp_time32));
        } else
#endif
        {
                if (!req->oldptr)
                        return SYSCTL_OUT(req, 0, sizeof(cp_time));
                error = SYSCTL_OUT(req, cp_time, sizeof(cp_time));
        }
        return error;
}

SYSCTL_PROC(_kern, OID_AUTO, cp_time, CTLTYPE_LONG|CTLFLAG_RD|CTLFLAG_MPSAFE,
    0,0, sysctl_kern_cp_time, "LU", "CPU time statistics");

static long empty[CPUSTATES];

static int
sysctl_kern_cp_times(SYSCTL_HANDLER_ARGS)
{
        struct pcpu *pcpu;
        int error;
        int c;
        long *cp_time;
#ifdef SCTL_MASK32
        unsigned int cp_time32[CPUSTATES];
        int i;
#endif

        if (!req->oldptr) {
#ifdef SCTL_MASK32
                if (req->flags & SCTL_MASK32)
                        return SYSCTL_OUT(req, 0, sizeof(cp_time32) * (mp_maxid + 1));
                else
#endif
                        return SYSCTL_OUT(req, 0, sizeof(long) * CPUSTATES * (mp_maxid + 1));
        }
        for (error = 0, c = 0; error == 0 && c <= mp_maxid; c++) {
                if (!CPU_ABSENT(c)) {
                        pcpu = pcpu_find(c);
                        cp_time = pcpu->pc_cp_time;
                } else {
                        cp_time = empty;
                }
#ifdef SCTL_MASK32
                if (req->flags & SCTL_MASK32) {
                        for (i = 0; i < CPUSTATES; i++)
                                cp_time32[i] = (unsigned int)cp_time[i];
                        error = SYSCTL_OUT(req, cp_time32, sizeof(cp_time32));
                } else
#endif
                        error = SYSCTL_OUT(req, cp_time, sizeof(long) * CPUSTATES);
        }
        return error;
}

SYSCTL_PROC(_kern, OID_AUTO, cp_times, CTLTYPE_LONG|CTLFLAG_RD|CTLFLAG_MPSAFE,
    0,0, sysctl_kern_cp_times, "LU", "per-CPU time statistics");

#ifdef DEADLKRES
static const char *blessed[] = {
        "getblk",
        "so_snd_sx",
        "so_rcv_sx",
        NULL
};
static int slptime_threshold = 1800;
static int blktime_threshold = 900;
static int sleepfreq = 3;

static void
deadlres_td_on_lock(struct proc *p, struct thread *td, int blkticks)
{
        int tticks;

        sx_assert(&allproc_lock, SX_LOCKED);
        PROC_LOCK_ASSERT(p, MA_OWNED);
        THREAD_LOCK_ASSERT(td, MA_OWNED);
        /*
         * The thread should be blocked on a turnstile, simply check
         * if the turnstile channel is in good state.
         */
        MPASS(td->td_blocked != NULL);

        tticks = ticks - td->td_blktick;
        if (tticks > blkticks)
                /*
                 * Accordingly with provided thresholds, this thread is stuck
                 * for too long on a turnstile.
                 */
                panic("%s: possible deadlock detected for %p (%s), "
                    "blocked for %d ticks\n", __func__,
                    td, sched_tdname(td), tticks);
}

static void
deadlres_td_sleep_q(struct proc *p, struct thread *td, int slpticks)
{
        const void *wchan;
        int i, slptype, tticks;

        sx_assert(&allproc_lock, SX_LOCKED);
        PROC_LOCK_ASSERT(p, MA_OWNED);
        THREAD_LOCK_ASSERT(td, MA_OWNED);
        /*
         * Check if the thread is sleeping on a lock, otherwise skip the check.
         * Drop the thread lock in order to avoid a LOR with the sleepqueue
         * spinlock.
         */
        wchan = td->td_wchan;
        tticks = ticks - td->td_slptick;
        slptype = sleepq_type(wchan);
        if ((slptype == SLEEPQ_SX || slptype == SLEEPQ_LK) &&
            tticks > slpticks) {
                /*
                 * Accordingly with provided thresholds, this thread is stuck
                 * for too long on a sleepqueue.
                 * However, being on a sleepqueue, we might still check for the
                 * blessed list.
                 */
                for (i = 0; blessed[i] != NULL; i++)
                        if (!strcmp(blessed[i], td->td_wmesg))
                                return;

                panic("%s: possible deadlock detected for %p (%s), "
                    "blocked for %d ticks\n", __func__,
                    td, sched_tdname(td), tticks);
        }
}

static void
deadlkres(void)
{
        struct proc *p;
        struct thread *td;
        int blkticks, slpticks, tryl;

        tryl = 0;
        for (;;) {
                blkticks = blktime_threshold * hz;
                slpticks = slptime_threshold * hz;

                /*
                 * Avoid to sleep on the sx_lock in order to avoid a
                 * possible priority inversion problem leading to
                 * starvation.
                 * If the lock can't be held after 100 tries, panic.
                 */
                if (!sx_try_slock(&allproc_lock)) {
                        if (tryl > 100)
                                panic("%s: possible deadlock detected "
                                    "on allproc_lock\n", __func__);
                        tryl++;
                        pause("allproc", sleepfreq * hz);
                        continue;
                }
                tryl = 0;
                FOREACH_PROC_IN_SYSTEM(p) {
                        PROC_LOCK(p);
                        if (p->p_state == PRS_NEW) {
                                PROC_UNLOCK(p);
                                continue;
                        }
                        FOREACH_THREAD_IN_PROC(p, td) {
                                thread_lock(td);
                                if (TD_ON_LOCK(td))
                                        deadlres_td_on_lock(p, td,
                                            blkticks);
                                else if (TD_IS_SLEEPING(td))
                                        deadlres_td_sleep_q(p, td,
                                            slpticks);
                                thread_unlock(td);
                        }
                        PROC_UNLOCK(p);
                }
                sx_sunlock(&allproc_lock);

                /* Sleep for sleepfreq seconds. */
                pause("-", sleepfreq * hz);
        }
}

static struct kthread_desc deadlkres_kd = {
        "deadlkres",
        deadlkres,
        (struct thread **)NULL
};

SYSINIT(deadlkres, SI_SUB_CLOCKS, SI_ORDER_ANY, kthread_start, &deadlkres_kd);

static SYSCTL_NODE(_debug, OID_AUTO, deadlkres, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
    "Deadlock resolver");
SYSCTL_INT(_debug_deadlkres, OID_AUTO, slptime_threshold, CTLFLAG_RWTUN,
    &slptime_threshold, 0,
    "Number of seconds within is valid to sleep on a sleepqueue");
SYSCTL_INT(_debug_deadlkres, OID_AUTO, blktime_threshold, CTLFLAG_RWTUN,
    &blktime_threshold, 0,
    "Number of seconds within is valid to block on a turnstile");
SYSCTL_INT(_debug_deadlkres, OID_AUTO, sleepfreq, CTLFLAG_RWTUN, &sleepfreq, 0,
    "Number of seconds between any deadlock resolver thread run");
#endif  /* DEADLKRES */

void
read_cpu_time(long *cp_time)
{
        struct pcpu *pc;
        int i, j;

        /* Sum up global cp_time[]. */
        bzero(cp_time, sizeof(long) * CPUSTATES);
        CPU_FOREACH(i) {
                pc = pcpu_find(i);
                for (j = 0; j < CPUSTATES; j++)
                        cp_time[j] += pc->pc_cp_time[j];
        }
}

#include <sys/watchdog.h>

static long watchdog_ticks;
static int watchdog_enabled;
static void watchdog_fire(void);
static void watchdog_config(void *, u_int, int *);

static void
watchdog_attach(void)
{
        EVENTHANDLER_REGISTER(watchdog_list, watchdog_config, NULL, 0);
}

/*
 * Clock handling routines.
 *
 * This code is written to operate with two timers that run independently of
 * each other.
 *
 * The main timer, running hz times per second, is used to trigger interval
 * timers, timeouts and rescheduling as needed.
 *
 * The second timer handles kernel and user profiling,
 * and does resource use estimation.  If the second timer is programmable,
 * it is randomized to avoid aliasing between the two clocks.  For example,
 * the randomization prevents an adversary from always giving up the cpu
 * just before its quantum expires.  Otherwise, it would never accumulate
 * cpu ticks.  The mean frequency of the second timer is stathz.
 *
 * If no second timer exists, stathz will be zero; in this case we drive
 * profiling and statistics off the main clock.  This WILL NOT be accurate;
 * do not do it unless absolutely necessary.
 *
 * The statistics clock may (or may not) be run at a higher rate while
 * profiling.  This profile clock runs at profhz.  We require that profhz
 * be an integral multiple of stathz.
 *
 * If the statistics clock is running fast, it must be divided by the ratio
 * profhz/stathz for statistics.  (For profiling, every tick counts.)
 *
 * Time-of-day is maintained using a "timecounter", which may or may
 * not be related to the hardware generating the above mentioned
 * interrupts.
 */

int     stathz;
int     profhz;
int     profprocs;
int     psratio;

DPCPU_DEFINE_STATIC(long, pcputicks);   /* Per-CPU version of ticks. */
#ifdef DEVICE_POLLING
static int devpoll_run = 0;
#endif

static void
ast_oweupc(struct thread *td, int tda __unused)
{
        if ((td->td_proc->p_flag & P_PROFIL) == 0)
                return;
        addupc_task(td, td->td_profil_addr, td->td_profil_ticks);
        td->td_profil_ticks = 0;
        td->td_pflags &= ~TDP_OWEUPC;
}

static void
ast_alrm(struct thread *td, int tda __unused)
{
        struct proc *p;

        p = td->td_proc;
        PROC_LOCK(p);
        kern_psignal(p, SIGVTALRM);
        PROC_UNLOCK(p);
}

static void
ast_prof(struct thread *td, int tda __unused)
{
        struct proc *p;

        p = td->td_proc;
        PROC_LOCK(p);
        kern_psignal(p, SIGPROF);
        PROC_UNLOCK(p);
}

/*
 * Initialize clock frequencies and start both clocks running.
 */
static void
initclocks(void *dummy __unused)
{
        int i;

        /*
         * Set divisors to 1 (normal case) and let the machine-specific
         * code do its bit.
         */
        mtx_init(&time_lock, "time lock", NULL, MTX_DEF);
        cpu_initclocks();

        /*
         * Compute profhz/stathz, and fix profhz if needed.
         */
        i = stathz ? stathz : hz;
        if (profhz == 0)
                profhz = i;
        psratio = profhz / i;

        ast_register(TDA_OWEUPC, ASTR_ASTF_REQUIRED, 0, ast_oweupc);
        ast_register(TDA_ALRM, ASTR_ASTF_REQUIRED, 0, ast_alrm);
        ast_register(TDA_PROF, ASTR_ASTF_REQUIRED, 0, ast_prof);

#ifdef SW_WATCHDOG
        /* Enable hardclock watchdog now, even if a hardware watchdog exists. */
        watchdog_attach();
#else
        /* Volunteer to run a software watchdog. */
        if (wdog_software_attach == NULL)
                wdog_software_attach = watchdog_attach;
#endif
}
SYSINIT(clocks, SI_SUB_CLOCKS, SI_ORDER_FIRST, initclocks, NULL);

static __noinline void
hardclock_itimer(struct thread *td, struct pstats *pstats, int cnt, int usermode)
{
        struct proc *p;
        int ast;

        ast = 0;
        p = td->td_proc;
        if (usermode &&
            timevalisset(&pstats->p_timer[ITIMER_VIRTUAL].it_value)) {
                PROC_ITIMLOCK(p);
                if (itimerdecr(&pstats->p_timer[ITIMER_VIRTUAL],
                    tick * cnt) == 0)
                        ast |= TDAI(TDA_ALRM);
                PROC_ITIMUNLOCK(p);
        }
        if (timevalisset(&pstats->p_timer[ITIMER_PROF].it_value)) {
                PROC_ITIMLOCK(p);
                if (itimerdecr(&pstats->p_timer[ITIMER_PROF],
                    tick * cnt) == 0)
                        ast |= TDAI(TDA_PROF);
                PROC_ITIMUNLOCK(p);
        }
        if (ast != 0)
                ast_sched_mask(td, ast);
}

void
hardclock(int cnt, int usermode)
{
        struct pstats *pstats;
        struct thread *td = curthread;
        struct proc *p = td->td_proc;
        long global, newticks, *t;

        /*
         * Update per-CPU and possibly global ticks values.
         */
        t = DPCPU_PTR(pcputicks);
        *t += cnt;
        global = atomic_load_long(&ticksl);
        do {
                newticks = *t - global;
                if (newticks <= 0) {
                        if (newticks < -1)
                                *t = global - 1;
                        newticks = 0;
                        break;
                }
        } while (!atomic_fcmpset_long(&ticksl, &global, *t));

        /*
         * Run current process's virtual and profile time, as needed.
         */
        pstats = p->p_stats;
        if (__predict_false(
            timevalisset(&pstats->p_timer[ITIMER_VIRTUAL].it_value) ||
            timevalisset(&pstats->p_timer[ITIMER_PROF].it_value)))
                hardclock_itimer(td, pstats, cnt, usermode);

#ifdef  HWPMC_HOOKS
        if (PMC_CPU_HAS_SAMPLES(PCPU_GET(cpuid)))
                PMC_CALL_HOOK_UNLOCKED(curthread, PMC_FN_DO_SAMPLES, NULL);
        if (td->td_intr_frame != NULL)
                PMC_SOFT_CALL_TF( , , clock, hard, td->td_intr_frame);
#endif
        /* We are in charge to handle this tick duty. */
        if (newticks > 0) {
                tc_ticktock(newticks);
#ifdef DEVICE_POLLING
                /* Dangerous and no need to call these things concurrently. */
                if (atomic_cmpset_acq_int(&devpoll_run, 0, 1)) {
                        /* This is very short and quick. */
                        hardclock_device_poll();
                        atomic_store_rel_int(&devpoll_run, 0);
                }
#endif /* DEVICE_POLLING */
                if (watchdog_enabled > 0) {
                        long left;

                        left = atomic_fetchadd_long(&watchdog_ticks, -newticks);
                        if (left > 0 && left <= newticks)
                                watchdog_fire();
                }
                intr_event_handle(clk_intr_event, NULL);
        }
        if (curcpu == CPU_FIRST())
                cpu_tick_calibration();
        if (__predict_false(DPCPU_GET(epoch_cb_count)))
                GROUPTASK_ENQUEUE(DPCPU_PTR(epoch_cb_task));
}

void
hardclock_sync(int cpu)
{
        long *t;

        KASSERT(!CPU_ABSENT(cpu), ("Absent CPU %d", cpu));

        t = DPCPU_ID_PTR(cpu, pcputicks);
        *t = ticksl;
}

/*
 * Regular integer scaling formula without losing precision:
 */
#define TIME_INT_SCALE(value, mul, div) \
        (((value) / (div)) * (mul) + (((value) % (div)) * (mul)) / (div))

/*
 * Macro for converting seconds and microseconds into actual ticks,
 * based on the given hz value:
 */
#define TIME_TO_TICKS(sec, usec, hz) \
        ((sec) * (hz) + TIME_INT_SCALE(usec, hz, 1 << 6) / (1000000 >> 6))

#define TIME_ASSERT_VALID_HZ(hz)        \
        _Static_assert(TIME_TO_TICKS(INT_MAX / (hz) - 1, 999999, hz) >= 0 && \
                       TIME_TO_TICKS(INT_MAX / (hz) - 1, 999999, hz) < INT_MAX, \
                       "tvtohz() can overflow the regular integer type")

/*
 * Compile time assert the maximum and minimum values to fit into a
 * regular integer when computing TIME_TO_TICKS():
 */
TIME_ASSERT_VALID_HZ(HZ_MAXIMUM);
TIME_ASSERT_VALID_HZ(HZ_MINIMUM);

/*
 * The formula is mostly linear, but test some more common values just
 * in case:
 */
TIME_ASSERT_VALID_HZ(1024);
TIME_ASSERT_VALID_HZ(1000);
TIME_ASSERT_VALID_HZ(128);
TIME_ASSERT_VALID_HZ(100);

/*
 * Compute number of ticks representing the specified amount of time.
 * If the specified time is negative, a value of 1 is returned. This
 * function returns a value from 1 up to and including INT_MAX.
 */
int
tvtohz(struct timeval *tv)
{
        int retval;

        /*
         * The values passed here may come from user-space and these
         * checks ensure "tv_usec" is within its allowed range:
         */

        /* check for tv_usec underflow */
        if (__predict_false(tv->tv_usec < 0)) {
                tv->tv_sec += tv->tv_usec / 1000000;
                tv->tv_usec = tv->tv_usec % 1000000;
                /* convert tv_usec to a positive value */
                if (__predict_true(tv->tv_usec < 0)) {
                        tv->tv_usec += 1000000;
                        tv->tv_sec -= 1;
                }
        /* check for tv_usec overflow */
        } else if (__predict_false(tv->tv_usec >= 1000000)) {
                tv->tv_sec += tv->tv_usec / 1000000;
                tv->tv_usec = tv->tv_usec % 1000000;
        }

        /* check for tv_sec underflow */
        if (__predict_false(tv->tv_sec < 0))
                return (1);
        /* check for tv_sec overflow (including room for the tv_usec part) */
        else if (__predict_false(tv->tv_sec >= tick_seconds_max))
                return (INT_MAX);

        /* cast to "int" to avoid platform differences */
        retval = TIME_TO_TICKS((int)tv->tv_sec, (int)tv->tv_usec, hz);

        /* add one additional tick */
        return (retval + 1);
}

/*
 * Start profiling on a process.
 *
 * Kernel profiling passes proc0 which never exits and hence
 * keeps the profile clock running constantly.
 */
void
startprofclock(struct proc *p)
{

        PROC_LOCK_ASSERT(p, MA_OWNED);
        if (p->p_flag & P_STOPPROF)
                return;
        if ((p->p_flag & P_PROFIL) == 0) {
                p->p_flag |= P_PROFIL;
                mtx_lock(&time_lock);
                if (++profprocs == 1)
                        cpu_startprofclock();
                mtx_unlock(&time_lock);
        }
}

/*
 * Stop profiling on a process.
 */
void
stopprofclock(struct proc *p)
{

        PROC_LOCK_ASSERT(p, MA_OWNED);
        if (p->p_flag & P_PROFIL) {
                if (p->p_profthreads != 0) {
                        while (p->p_profthreads != 0) {
                                p->p_flag |= P_STOPPROF;
                                msleep(&p->p_profthreads, &p->p_mtx, PPAUSE,
                                    "stopprof", 0);
                        }
                }
                if ((p->p_flag & P_PROFIL) == 0)
                        return;
                p->p_flag &= ~P_PROFIL;
                mtx_lock(&time_lock);
                if (--profprocs == 0)
                        cpu_stopprofclock();
                mtx_unlock(&time_lock);
        }
}

/*
 * Statistics clock.  Updates rusage information and calls the scheduler
 * to adjust priorities of the active thread.
 *
 * This should be called by all active processors.
 */
void
statclock(int cnt, int usermode)
{
        struct rusage *ru;
        struct vmspace *vm;
        struct thread *td;
        struct proc *p;
        long rss;
        long *cp_time;
        uint64_t runtime, new_switchtime;

        td = curthread;
        p = td->td_proc;

        cp_time = (long *)PCPU_PTR(cp_time);
        if (usermode) {
                /*
                 * Charge the time as appropriate.
                 */
                td->td_uticks += cnt;
                if (p->p_nice > NZERO)
                        cp_time[CP_NICE] += cnt;
                else
                        cp_time[CP_USER] += cnt;
        } else {
                /*
                 * Came from kernel mode, so we were:
                 * - handling an interrupt,
                 * - doing syscall or trap work on behalf of the current
                 *   user process, or
                 * - spinning in the idle loop.
                 * Whichever it is, charge the time as appropriate.
                 * Note that we charge interrupts to the current process,
                 * regardless of whether they are ``for'' that process,
                 * so that we know how much of its real time was spent
                 * in ``non-process'' (i.e., interrupt) work.
                 */
                if ((td->td_pflags & TDP_ITHREAD) ||
                    td->td_intr_nesting_level >= 2) {
                        td->td_iticks += cnt;
                        cp_time[CP_INTR] += cnt;
                } else {
                        td->td_pticks += cnt;
                        td->td_sticks += cnt;
                        if (!TD_IS_IDLETHREAD(td))
                                cp_time[CP_SYS] += cnt;
                        else
                                cp_time[CP_IDLE] += cnt;
                }
        }

        /* Update resource usage integrals and maximums. */
        MPASS(p->p_vmspace != NULL);
        vm = p->p_vmspace;
        ru = &td->td_ru;
        ru->ru_ixrss += pgtok(vm->vm_tsize) * cnt;
        ru->ru_idrss += pgtok(vm->vm_dsize) * cnt;
        ru->ru_isrss += pgtok(vm->vm_ssize) * cnt;
        rss = pgtok(vmspace_resident_count(vm));
        if (ru->ru_maxrss < rss)
                ru->ru_maxrss = rss;
        KTR_POINT2(KTR_SCHED, "thread", sched_tdname(td), "statclock",
            "prio:%d", td->td_priority, "stathz:%d", (stathz)?stathz:hz);
        SDT_PROBE2(sched, , , tick, td, td->td_proc);
        thread_lock_flags(td, MTX_QUIET);

        /*
         * Compute the amount of time during which the current
         * thread was running, and add that to its total so far.
         */
        new_switchtime = cpu_ticks();
        runtime = new_switchtime - PCPU_GET(switchtime);
        td->td_runtime += runtime;
        td->td_incruntime += runtime;
        PCPU_SET(switchtime, new_switchtime);

        sched_clock(td, cnt);
        thread_unlock(td);
#ifdef HWPMC_HOOKS
        if (td->td_intr_frame != NULL)
                PMC_SOFT_CALL_TF( , , clock, stat, td->td_intr_frame);
#endif
}

void
profclock(int cnt, int usermode, uintfptr_t pc)
{
        struct thread *td;

        td = curthread;
        if (usermode) {
                /*
                 * Came from user mode; CPU was in user state.
                 * If this process is being profiled, record the tick.
                 * if there is no related user location yet, don't
                 * bother trying to count it.
                 */
                if (td->td_proc->p_flag & P_PROFIL)
                        addupc_intr(td, pc, cnt);
        }
#ifdef HWPMC_HOOKS
        if (td->td_intr_frame != NULL)
                PMC_SOFT_CALL_TF( , , clock, prof, td->td_intr_frame);
#endif
}

/*
 * Return information about system clocks.
 */
static int
sysctl_kern_clockrate(SYSCTL_HANDLER_ARGS)
{
        struct clockinfo clkinfo;
        /*
         * Construct clockinfo structure.
         */
        bzero(&clkinfo, sizeof(clkinfo));
        clkinfo.hz = hz;
        clkinfo.tick = tick;
        clkinfo.profhz = profhz;
        clkinfo.stathz = stathz ? stathz : hz;
        return (sysctl_handle_opaque(oidp, &clkinfo, sizeof clkinfo, req));
}

SYSCTL_PROC(_kern, KERN_CLOCKRATE, clockrate,
        CTLTYPE_STRUCT|CTLFLAG_RD|CTLFLAG_MPSAFE,
        0, 0, sysctl_kern_clockrate, "S,clockinfo",
        "Rate and period of various kernel clocks");

static void
watchdog_config(void *unused __unused, u_int cmd, int *error)
{
        u_int u;

        u = cmd & WD_INTERVAL;
        if (u >= WD_TO_1SEC) {
                watchdog_ticks = (1 << (u - WD_TO_1SEC)) * hz;
                watchdog_enabled = 1;
                *error = 0;
        } else {
                watchdog_enabled = 0;
        }
}

/*
 * Handle a watchdog timeout by dropping to DDB or panicking.
 */
static void
watchdog_fire(void)
{

#if defined(KDB) && !defined(KDB_UNATTENDED)
        kdb_backtrace();
        kdb_enter(KDB_WHY_WATCHDOG, "watchdog timeout");
#else
        panic("watchdog timeout");
#endif
}