1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1982, 1986, 1991, 1993
5 *	The Regents of the University of California.  All rights reserved.
6 * (c) UNIX System Laboratories, Inc.
7 * All or some portions of this file are derived from material licensed
8 * to the University of California by American Telephone and Telegraph
9 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
10 * the permission of UNIX System Laboratories, Inc.
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 *    notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 *    notice, this list of conditions and the following disclaimer in the
19 *    documentation and/or other materials provided with the distribution.
20 * 3. Neither the name of the University nor the names of its contributors
21 *    may be used to endorse or promote products derived from this software
22 *    without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 */
36
37#include <sys/cdefs.h>
38#include "opt_kdb.h"
39#include "opt_device_polling.h"
40#include "opt_hwpmc_hooks.h"
41#include "opt_ntp.h"
42#include "opt_watchdog.h"
43
44#include <sys/param.h>
45#include <sys/systm.h>
46#include <sys/callout.h>
47#include <sys/epoch.h>
48#include <sys/eventhandler.h>
49#include <sys/gtaskqueue.h>
50#include <sys/kdb.h>
51#include <sys/kernel.h>
52#include <sys/kthread.h>
53#include <sys/ktr.h>
54#include <sys/lock.h>
55#include <sys/mutex.h>
56#include <sys/proc.h>
57#include <sys/resource.h>
58#include <sys/resourcevar.h>
59#include <sys/sched.h>
60#include <sys/sdt.h>
61#include <sys/signalvar.h>
62#include <sys/sleepqueue.h>
63#include <sys/smp.h>
64#include <vm/vm.h>
65#include <vm/pmap.h>
66#include <vm/vm_map.h>
67#include <sys/sysctl.h>
68#include <sys/bus.h>
69#include <sys/interrupt.h>
70#include <sys/limits.h>
71#include <sys/timetc.h>
72
73#ifdef HWPMC_HOOKS
74#include <sys/pmckern.h>
75PMC_SOFT_DEFINE( , , clock, hard);
76PMC_SOFT_DEFINE( , , clock, stat);
77PMC_SOFT_DEFINE_EX( , , clock, prof, \
78    cpu_startprofclock, cpu_stopprofclock);
79#endif
80
81#ifdef DEVICE_POLLING
82extern void hardclock_device_poll(void);
83#endif /* DEVICE_POLLING */
84
85/* Spin-lock protecting profiling statistics. */
86static struct mtx time_lock;
87
88SDT_PROVIDER_DECLARE(sched);
89SDT_PROBE_DEFINE2(sched, , , tick, "struct thread *", "struct proc *");
90
91static int
92sysctl_kern_cp_time(SYSCTL_HANDLER_ARGS)
93{
94	int error;
95	long cp_time[CPUSTATES];
96#ifdef SCTL_MASK32
97	int i;
98	unsigned int cp_time32[CPUSTATES];
99#endif
100
101	read_cpu_time(cp_time);
102#ifdef SCTL_MASK32
103	if (req->flags & SCTL_MASK32) {
104		if (!req->oldptr)
105			return SYSCTL_OUT(req, 0, sizeof(cp_time32));
106		for (i = 0; i < CPUSTATES; i++)
107			cp_time32[i] = (unsigned int)cp_time[i];
108		error = SYSCTL_OUT(req, cp_time32, sizeof(cp_time32));
109	} else
110#endif
111	{
112		if (!req->oldptr)
113			return SYSCTL_OUT(req, 0, sizeof(cp_time));
114		error = SYSCTL_OUT(req, cp_time, sizeof(cp_time));
115	}
116	return error;
117}
118
119SYSCTL_PROC(_kern, OID_AUTO, cp_time, CTLTYPE_LONG|CTLFLAG_RD|CTLFLAG_MPSAFE,
120    0,0, sysctl_kern_cp_time, "LU", "CPU time statistics");
121
122static long empty[CPUSTATES];
123
124static int
125sysctl_kern_cp_times(SYSCTL_HANDLER_ARGS)
126{
127	struct pcpu *pcpu;
128	int error;
129	int c;
130	long *cp_time;
131#ifdef SCTL_MASK32
132	unsigned int cp_time32[CPUSTATES];
133	int i;
134#endif
135
136	if (!req->oldptr) {
137#ifdef SCTL_MASK32
138		if (req->flags & SCTL_MASK32)
139			return SYSCTL_OUT(req, 0, sizeof(cp_time32) * (mp_maxid + 1));
140		else
141#endif
142			return SYSCTL_OUT(req, 0, sizeof(long) * CPUSTATES * (mp_maxid + 1));
143	}
144	for (error = 0, c = 0; error == 0 && c <= mp_maxid; c++) {
145		if (!CPU_ABSENT(c)) {
146			pcpu = pcpu_find(c);
147			cp_time = pcpu->pc_cp_time;
148		} else {
149			cp_time = empty;
150		}
151#ifdef SCTL_MASK32
152		if (req->flags & SCTL_MASK32) {
153			for (i = 0; i < CPUSTATES; i++)
154				cp_time32[i] = (unsigned int)cp_time[i];
155			error = SYSCTL_OUT(req, cp_time32, sizeof(cp_time32));
156		} else
157#endif
158			error = SYSCTL_OUT(req, cp_time, sizeof(long) * CPUSTATES);
159	}
160	return error;
161}
162
163SYSCTL_PROC(_kern, OID_AUTO, cp_times, CTLTYPE_LONG|CTLFLAG_RD|CTLFLAG_MPSAFE,
164    0,0, sysctl_kern_cp_times, "LU", "per-CPU time statistics");
165
166#ifdef DEADLKRES
167static const char *blessed[] = {
168	"getblk",
169	"so_snd_sx",
170	"so_rcv_sx",
171	NULL
172};
173static int slptime_threshold = 1800;
174static int blktime_threshold = 900;
175static int sleepfreq = 3;
176
177static void
178deadlres_td_on_lock(struct proc *p, struct thread *td, int blkticks)
179{
180	int tticks;
181
182	sx_assert(&allproc_lock, SX_LOCKED);
183	PROC_LOCK_ASSERT(p, MA_OWNED);
184	THREAD_LOCK_ASSERT(td, MA_OWNED);
185	/*
186	 * The thread should be blocked on a turnstile, simply check
187	 * if the turnstile channel is in good state.
188	 */
189	MPASS(td->td_blocked != NULL);
190
191	tticks = ticks - td->td_blktick;
192	if (tticks > blkticks)
193		/*
194		 * Accordingly with provided thresholds, this thread is stuck
195		 * for too long on a turnstile.
196		 */
197		panic("%s: possible deadlock detected for %p (%s), "
198		    "blocked for %d ticks\n", __func__,
199		    td, sched_tdname(td), tticks);
200}
201
202static void
203deadlres_td_sleep_q(struct proc *p, struct thread *td, int slpticks)
204{
205	const void *wchan;
206	int i, slptype, tticks;
207
208	sx_assert(&allproc_lock, SX_LOCKED);
209	PROC_LOCK_ASSERT(p, MA_OWNED);
210	THREAD_LOCK_ASSERT(td, MA_OWNED);
211	/*
212	 * Check if the thread is sleeping on a lock, otherwise skip the check.
213	 * Drop the thread lock in order to avoid a LOR with the sleepqueue
214	 * spinlock.
215	 */
216	wchan = td->td_wchan;
217	tticks = ticks - td->td_slptick;
218	slptype = sleepq_type(wchan);
219	if ((slptype == SLEEPQ_SX || slptype == SLEEPQ_LK) &&
220	    tticks > slpticks) {
221		/*
222		 * Accordingly with provided thresholds, this thread is stuck
223		 * for too long on a sleepqueue.
224		 * However, being on a sleepqueue, we might still check for the
225		 * blessed list.
226		 */
227		for (i = 0; blessed[i] != NULL; i++)
228			if (!strcmp(blessed[i], td->td_wmesg))
229				return;
230
231		panic("%s: possible deadlock detected for %p (%s), "
232		    "blocked for %d ticks\n", __func__,
233		    td, sched_tdname(td), tticks);
234	}
235}
236
237static void
238deadlkres(void)
239{
240	struct proc *p;
241	struct thread *td;
242	int blkticks, slpticks, tryl;
243
244	tryl = 0;
245	for (;;) {
246		blkticks = blktime_threshold * hz;
247		slpticks = slptime_threshold * hz;
248
249		/*
250		 * Avoid to sleep on the sx_lock in order to avoid a
251		 * possible priority inversion problem leading to
252		 * starvation.
253		 * If the lock can't be held after 100 tries, panic.
254		 */
255		if (!sx_try_slock(&allproc_lock)) {
256			if (tryl > 100)
257				panic("%s: possible deadlock detected "
258				    "on allproc_lock\n", __func__);
259			tryl++;
260			pause("allproc", sleepfreq * hz);
261			continue;
262		}
263		tryl = 0;
264		FOREACH_PROC_IN_SYSTEM(p) {
265			PROC_LOCK(p);
266			if (p->p_state == PRS_NEW) {
267				PROC_UNLOCK(p);
268				continue;
269			}
270			FOREACH_THREAD_IN_PROC(p, td) {
271				thread_lock(td);
272				if (TD_ON_LOCK(td))
273					deadlres_td_on_lock(p, td,
274					    blkticks);
275				else if (TD_IS_SLEEPING(td))
276					deadlres_td_sleep_q(p, td,
277					    slpticks);
278				thread_unlock(td);
279			}
280			PROC_UNLOCK(p);
281		}
282		sx_sunlock(&allproc_lock);
283
284		/* Sleep for sleepfreq seconds. */
285		pause("-", sleepfreq * hz);
286	}
287}
288
289static struct kthread_desc deadlkres_kd = {
290	"deadlkres",
291	deadlkres,
292	(struct thread **)NULL
293};
294
295SYSINIT(deadlkres, SI_SUB_CLOCKS, SI_ORDER_ANY, kthread_start, &deadlkres_kd);
296
297static SYSCTL_NODE(_debug, OID_AUTO, deadlkres, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
298    "Deadlock resolver");
299SYSCTL_INT(_debug_deadlkres, OID_AUTO, slptime_threshold, CTLFLAG_RWTUN,
300    &slptime_threshold, 0,
301    "Number of seconds within is valid to sleep on a sleepqueue");
302SYSCTL_INT(_debug_deadlkres, OID_AUTO, blktime_threshold, CTLFLAG_RWTUN,
303    &blktime_threshold, 0,
304    "Number of seconds within is valid to block on a turnstile");
305SYSCTL_INT(_debug_deadlkres, OID_AUTO, sleepfreq, CTLFLAG_RWTUN, &sleepfreq, 0,
306    "Number of seconds between any deadlock resolver thread run");
307#endif	/* DEADLKRES */
308
309void
310read_cpu_time(long *cp_time)
311{
312	struct pcpu *pc;
313	int i, j;
314
315	/* Sum up global cp_time[]. */
316	bzero(cp_time, sizeof(long) * CPUSTATES);
317	CPU_FOREACH(i) {
318		pc = pcpu_find(i);
319		for (j = 0; j < CPUSTATES; j++)
320			cp_time[j] += pc->pc_cp_time[j];
321	}
322}
323
324#include <sys/watchdog.h>
325
326static int watchdog_ticks;
327static int watchdog_enabled;
328static void watchdog_fire(void);
329static void watchdog_config(void *, u_int, int *);
330
331static void
332watchdog_attach(void)
333{
334	EVENTHANDLER_REGISTER(watchdog_list, watchdog_config, NULL, 0);
335}
336
337/*
338 * Clock handling routines.
339 *
340 * This code is written to operate with two timers that run independently of
341 * each other.
342 *
343 * The main timer, running hz times per second, is used to trigger interval
344 * timers, timeouts and rescheduling as needed.
345 *
346 * The second timer handles kernel and user profiling,
347 * and does resource use estimation.  If the second timer is programmable,
348 * it is randomized to avoid aliasing between the two clocks.  For example,
349 * the randomization prevents an adversary from always giving up the cpu
350 * just before its quantum expires.  Otherwise, it would never accumulate
351 * cpu ticks.  The mean frequency of the second timer is stathz.
352 *
353 * If no second timer exists, stathz will be zero; in this case we drive
354 * profiling and statistics off the main clock.  This WILL NOT be accurate;
355 * do not do it unless absolutely necessary.
356 *
357 * The statistics clock may (or may not) be run at a higher rate while
358 * profiling.  This profile clock runs at profhz.  We require that profhz
359 * be an integral multiple of stathz.
360 *
361 * If the statistics clock is running fast, it must be divided by the ratio
362 * profhz/stathz for statistics.  (For profiling, every tick counts.)
363 *
364 * Time-of-day is maintained using a "timecounter", which may or may
365 * not be related to the hardware generating the above mentioned
366 * interrupts.
367 */
368
369int	stathz;
370int	profhz;
371int	profprocs;
372volatile int	ticks;
373int	psratio;
374
375DPCPU_DEFINE_STATIC(int, pcputicks);	/* Per-CPU version of ticks. */
376#ifdef DEVICE_POLLING
377static int devpoll_run = 0;
378#endif
379
380static void
381ast_oweupc(struct thread *td, int tda __unused)
382{
383	if ((td->td_proc->p_flag & P_PROFIL) == 0)
384		return;
385	addupc_task(td, td->td_profil_addr, td->td_profil_ticks);
386	td->td_profil_ticks = 0;
387	td->td_pflags &= ~TDP_OWEUPC;
388}
389
390static void
391ast_alrm(struct thread *td, int tda __unused)
392{
393	struct proc *p;
394
395	p = td->td_proc;
396	PROC_LOCK(p);
397	kern_psignal(p, SIGVTALRM);
398	PROC_UNLOCK(p);
399}
400
401static void
402ast_prof(struct thread *td, int tda __unused)
403{
404	struct proc *p;
405
406	p = td->td_proc;
407	PROC_LOCK(p);
408	kern_psignal(p, SIGPROF);
409	PROC_UNLOCK(p);
410}
411
412/*
413 * Initialize clock frequencies and start both clocks running.
414 */
415static void
416initclocks(void *dummy __unused)
417{
418	int i;
419
420	/*
421	 * Set divisors to 1 (normal case) and let the machine-specific
422	 * code do its bit.
423	 */
424	mtx_init(&time_lock, "time lock", NULL, MTX_DEF);
425	cpu_initclocks();
426
427	/*
428	 * Compute profhz/stathz, and fix profhz if needed.
429	 */
430	i = stathz ? stathz : hz;
431	if (profhz == 0)
432		profhz = i;
433	psratio = profhz / i;
434
435	ast_register(TDA_OWEUPC, ASTR_ASTF_REQUIRED, 0, ast_oweupc);
436	ast_register(TDA_ALRM, ASTR_ASTF_REQUIRED, 0, ast_alrm);
437	ast_register(TDA_PROF, ASTR_ASTF_REQUIRED, 0, ast_prof);
438
439#ifdef SW_WATCHDOG
440	/* Enable hardclock watchdog now, even if a hardware watchdog exists. */
441	watchdog_attach();
442#else
443	/* Volunteer to run a software watchdog. */
444	if (wdog_software_attach == NULL)
445		wdog_software_attach = watchdog_attach;
446#endif
447}
448SYSINIT(clocks, SI_SUB_CLOCKS, SI_ORDER_FIRST, initclocks, NULL);
449
450static __noinline void
451hardclock_itimer(struct thread *td, struct pstats *pstats, int cnt, int usermode)
452{
453	struct proc *p;
454	int ast;
455
456	ast = 0;
457	p = td->td_proc;
458	if (usermode &&
459	    timevalisset(&pstats->p_timer[ITIMER_VIRTUAL].it_value)) {
460		PROC_ITIMLOCK(p);
461		if (itimerdecr(&pstats->p_timer[ITIMER_VIRTUAL],
462		    tick * cnt) == 0)
463			ast |= TDAI(TDA_ALRM);
464		PROC_ITIMUNLOCK(p);
465	}
466	if (timevalisset(&pstats->p_timer[ITIMER_PROF].it_value)) {
467		PROC_ITIMLOCK(p);
468		if (itimerdecr(&pstats->p_timer[ITIMER_PROF],
469		    tick * cnt) == 0)
470			ast |= TDAI(TDA_PROF);
471		PROC_ITIMUNLOCK(p);
472	}
473	if (ast != 0)
474		ast_sched_mask(td, ast);
475}
476
477void
478hardclock(int cnt, int usermode)
479{
480	struct pstats *pstats;
481	struct thread *td = curthread;
482	struct proc *p = td->td_proc;
483	int *t = DPCPU_PTR(pcputicks);
484	int global, i, newticks;
485
486	/*
487	 * Update per-CPU and possibly global ticks values.
488	 */
489	*t += cnt;
490	global = ticks;
491	do {
492		newticks = *t - global;
493		if (newticks <= 0) {
494			if (newticks < -1)
495				*t = global - 1;
496			newticks = 0;
497			break;
498		}
499	} while (!atomic_fcmpset_int(&ticks, &global, *t));
500
501	/*
502	 * Run current process's virtual and profile time, as needed.
503	 */
504	pstats = p->p_stats;
505	if (__predict_false(
506	    timevalisset(&pstats->p_timer[ITIMER_VIRTUAL].it_value) ||
507	    timevalisset(&pstats->p_timer[ITIMER_PROF].it_value)))
508		hardclock_itimer(td, pstats, cnt, usermode);
509
510#ifdef	HWPMC_HOOKS
511	if (PMC_CPU_HAS_SAMPLES(PCPU_GET(cpuid)))
512		PMC_CALL_HOOK_UNLOCKED(curthread, PMC_FN_DO_SAMPLES, NULL);
513	if (td->td_intr_frame != NULL)
514		PMC_SOFT_CALL_TF( , , clock, hard, td->td_intr_frame);
515#endif
516	/* We are in charge to handle this tick duty. */
517	if (newticks > 0) {
518		tc_ticktock(newticks);
519#ifdef DEVICE_POLLING
520		/* Dangerous and no need to call these things concurrently. */
521		if (atomic_cmpset_acq_int(&devpoll_run, 0, 1)) {
522			/* This is very short and quick. */
523			hardclock_device_poll();
524			atomic_store_rel_int(&devpoll_run, 0);
525		}
526#endif /* DEVICE_POLLING */
527		if (watchdog_enabled > 0) {
528			i = atomic_fetchadd_int(&watchdog_ticks, -newticks);
529			if (i > 0 && i <= newticks)
530				watchdog_fire();
531		}
532		intr_event_handle(clk_intr_event, NULL);
533	}
534	if (curcpu == CPU_FIRST())
535		cpu_tick_calibration();
536	if (__predict_false(DPCPU_GET(epoch_cb_count)))
537		GROUPTASK_ENQUEUE(DPCPU_PTR(epoch_cb_task));
538}
539
540void
541hardclock_sync(int cpu)
542{
543	int *t;
544	KASSERT(!CPU_ABSENT(cpu), ("Absent CPU %d", cpu));
545	t = DPCPU_ID_PTR(cpu, pcputicks);
546
547	*t = ticks;
548}
549
550/*
551 * Regular integer scaling formula without losing precision:
552 */
553#define	TIME_INT_SCALE(value, mul, div) \
554	(((value) / (div)) * (mul) + (((value) % (div)) * (mul)) / (div))
555
556/*
557 * Macro for converting seconds and microseconds into actual ticks,
558 * based on the given hz value:
559 */
560#define	TIME_TO_TICKS(sec, usec, hz) \
561	((sec) * (hz) + TIME_INT_SCALE(usec, hz, 1 << 6) / (1000000 >> 6))
562
563#define	TIME_ASSERT_VALID_HZ(hz)	\
564	_Static_assert(TIME_TO_TICKS(INT_MAX / (hz) - 1, 999999, hz) >= 0 && \
565		       TIME_TO_TICKS(INT_MAX / (hz) - 1, 999999, hz) < INT_MAX,	\
566		       "tvtohz() can overflow the regular integer type")
567
568/*
569 * Compile time assert the maximum and minimum values to fit into a
570 * regular integer when computing TIME_TO_TICKS():
571 */
572TIME_ASSERT_VALID_HZ(HZ_MAXIMUM);
573TIME_ASSERT_VALID_HZ(HZ_MINIMUM);
574
575/*
576 * The formula is mostly linear, but test some more common values just
577 * in case:
578 */
579TIME_ASSERT_VALID_HZ(1024);
580TIME_ASSERT_VALID_HZ(1000);
581TIME_ASSERT_VALID_HZ(128);
582TIME_ASSERT_VALID_HZ(100);
583
584/*
585 * Compute number of ticks representing the specified amount of time.
586 * If the specified time is negative, a value of 1 is returned. This
587 * function returns a value from 1 up to and including INT_MAX.
588 */
589int
590tvtohz(struct timeval *tv)
591{
592	int retval;
593
594	/*
595	 * The values passed here may come from user-space and these
596	 * checks ensure "tv_usec" is within its allowed range:
597	 */
598
599	/* check for tv_usec underflow */
600	if (__predict_false(tv->tv_usec < 0)) {
601		tv->tv_sec += tv->tv_usec / 1000000;
602		tv->tv_usec = tv->tv_usec % 1000000;
603		/* convert tv_usec to a positive value */
604		if (__predict_true(tv->tv_usec < 0)) {
605			tv->tv_usec += 1000000;
606			tv->tv_sec -= 1;
607		}
608	/* check for tv_usec overflow */
609	} else if (__predict_false(tv->tv_usec >= 1000000)) {
610		tv->tv_sec += tv->tv_usec / 1000000;
611		tv->tv_usec = tv->tv_usec % 1000000;
612	}
613
614	/* check for tv_sec underflow */
615	if (__predict_false(tv->tv_sec < 0))
616		return (1);
617	/* check for tv_sec overflow (including room for the tv_usec part) */
618	else if (__predict_false(tv->tv_sec >= tick_seconds_max))
619		return (INT_MAX);
620
621	/* cast to "int" to avoid platform differences */
622	retval = TIME_TO_TICKS((int)tv->tv_sec, (int)tv->tv_usec, hz);
623
624	/* add one additional tick */
625	return (retval + 1);
626}
627
628/*
629 * Start profiling on a process.
630 *
631 * Kernel profiling passes proc0 which never exits and hence
632 * keeps the profile clock running constantly.
633 */
634void
635startprofclock(struct proc *p)
636{
637
638	PROC_LOCK_ASSERT(p, MA_OWNED);
639	if (p->p_flag & P_STOPPROF)
640		return;
641	if ((p->p_flag & P_PROFIL) == 0) {
642		p->p_flag |= P_PROFIL;
643		mtx_lock(&time_lock);
644		if (++profprocs == 1)
645			cpu_startprofclock();
646		mtx_unlock(&time_lock);
647	}
648}
649
650/*
651 * Stop profiling on a process.
652 */
653void
654stopprofclock(struct proc *p)
655{
656
657	PROC_LOCK_ASSERT(p, MA_OWNED);
658	if (p->p_flag & P_PROFIL) {
659		if (p->p_profthreads != 0) {
660			while (p->p_profthreads != 0) {
661				p->p_flag |= P_STOPPROF;
662				msleep(&p->p_profthreads, &p->p_mtx, PPAUSE,
663				    "stopprof", 0);
664			}
665		}
666		if ((p->p_flag & P_PROFIL) == 0)
667			return;
668		p->p_flag &= ~P_PROFIL;
669		mtx_lock(&time_lock);
670		if (--profprocs == 0)
671			cpu_stopprofclock();
672		mtx_unlock(&time_lock);
673	}
674}
675
676/*
677 * Statistics clock.  Updates rusage information and calls the scheduler
678 * to adjust priorities of the active thread.
679 *
680 * This should be called by all active processors.
681 */
682void
683statclock(int cnt, int usermode)
684{
685	struct rusage *ru;
686	struct vmspace *vm;
687	struct thread *td;
688	struct proc *p;
689	long rss;
690	long *cp_time;
691	uint64_t runtime, new_switchtime;
692
693	td = curthread;
694	p = td->td_proc;
695
696	cp_time = (long *)PCPU_PTR(cp_time);
697	if (usermode) {
698		/*
699		 * Charge the time as appropriate.
700		 */
701		td->td_uticks += cnt;
702		if (p->p_nice > NZERO)
703			cp_time[CP_NICE] += cnt;
704		else
705			cp_time[CP_USER] += cnt;
706	} else {
707		/*
708		 * Came from kernel mode, so we were:
709		 * - handling an interrupt,
710		 * - doing syscall or trap work on behalf of the current
711		 *   user process, or
712		 * - spinning in the idle loop.
713		 * Whichever it is, charge the time as appropriate.
714		 * Note that we charge interrupts to the current process,
715		 * regardless of whether they are ``for'' that process,
716		 * so that we know how much of its real time was spent
717		 * in ``non-process'' (i.e., interrupt) work.
718		 */
719		if ((td->td_pflags & TDP_ITHREAD) ||
720		    td->td_intr_nesting_level >= 2) {
721			td->td_iticks += cnt;
722			cp_time[CP_INTR] += cnt;
723		} else {
724			td->td_pticks += cnt;
725			td->td_sticks += cnt;
726			if (!TD_IS_IDLETHREAD(td))
727				cp_time[CP_SYS] += cnt;
728			else
729				cp_time[CP_IDLE] += cnt;
730		}
731	}
732
733	/* Update resource usage integrals and maximums. */
734	MPASS(p->p_vmspace != NULL);
735	vm = p->p_vmspace;
736	ru = &td->td_ru;
737	ru->ru_ixrss += pgtok(vm->vm_tsize) * cnt;
738	ru->ru_idrss += pgtok(vm->vm_dsize) * cnt;
739	ru->ru_isrss += pgtok(vm->vm_ssize) * cnt;
740	rss = pgtok(vmspace_resident_count(vm));
741	if (ru->ru_maxrss < rss)
742		ru->ru_maxrss = rss;
743	KTR_POINT2(KTR_SCHED, "thread", sched_tdname(td), "statclock",
744	    "prio:%d", td->td_priority, "stathz:%d", (stathz)?stathz:hz);
745	SDT_PROBE2(sched, , , tick, td, td->td_proc);
746	thread_lock_flags(td, MTX_QUIET);
747
748	/*
749	 * Compute the amount of time during which the current
750	 * thread was running, and add that to its total so far.
751	 */
752	new_switchtime = cpu_ticks();
753	runtime = new_switchtime - PCPU_GET(switchtime);
754	td->td_runtime += runtime;
755	td->td_incruntime += runtime;
756	PCPU_SET(switchtime, new_switchtime);
757
758	sched_clock(td, cnt);
759	thread_unlock(td);
760#ifdef HWPMC_HOOKS
761	if (td->td_intr_frame != NULL)
762		PMC_SOFT_CALL_TF( , , clock, stat, td->td_intr_frame);
763#endif
764}
765
766void
767profclock(int cnt, int usermode, uintfptr_t pc)
768{
769	struct thread *td;
770
771	td = curthread;
772	if (usermode) {
773		/*
774		 * Came from user mode; CPU was in user state.
775		 * If this process is being profiled, record the tick.
776		 * if there is no related user location yet, don't
777		 * bother trying to count it.
778		 */
779		if (td->td_proc->p_flag & P_PROFIL)
780			addupc_intr(td, pc, cnt);
781	}
782#ifdef HWPMC_HOOKS
783	if (td->td_intr_frame != NULL)
784		PMC_SOFT_CALL_TF( , , clock, prof, td->td_intr_frame);
785#endif
786}
787
788/*
789 * Return information about system clocks.
790 */
791static int
792sysctl_kern_clockrate(SYSCTL_HANDLER_ARGS)
793{
794	struct clockinfo clkinfo;
795	/*
796	 * Construct clockinfo structure.
797	 */
798	bzero(&clkinfo, sizeof(clkinfo));
799	clkinfo.hz = hz;
800	clkinfo.tick = tick;
801	clkinfo.profhz = profhz;
802	clkinfo.stathz = stathz ? stathz : hz;
803	return (sysctl_handle_opaque(oidp, &clkinfo, sizeof clkinfo, req));
804}
805
806SYSCTL_PROC(_kern, KERN_CLOCKRATE, clockrate,
807	CTLTYPE_STRUCT|CTLFLAG_RD|CTLFLAG_MPSAFE,
808	0, 0, sysctl_kern_clockrate, "S,clockinfo",
809	"Rate and period of various kernel clocks");
810
811static void
812watchdog_config(void *unused __unused, u_int cmd, int *error)
813{
814	u_int u;
815
816	u = cmd & WD_INTERVAL;
817	if (u >= WD_TO_1SEC) {
818		watchdog_ticks = (1 << (u - WD_TO_1SEC)) * hz;
819		watchdog_enabled = 1;
820		*error = 0;
821	} else {
822		watchdog_enabled = 0;
823	}
824}
825
826/*
827 * Handle a watchdog timeout by dropping to DDB or panicking.
828 */
829static void
830watchdog_fire(void)
831{
832
833#if defined(KDB) && !defined(KDB_UNATTENDED)
834	kdb_backtrace();
835	kdb_enter(KDB_WHY_WATCHDOG, "watchdog timeout");
836#else
837	panic("watchdog timeout");
838#endif
839}
840