 @@ -1,1042 +1,1046 @@
-/* $NetBSD: kern_tc.c,v 1.74 2023/07/27 01:48:49 riastradh Exp $ */
+/* $NetBSD: kern_tc.c,v 1.75 2023/07/28 10:37:28 riastradh Exp $ */
 /*-
  * Copyright (c) 2008, 2009 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.
  */
 /*-
  * ----------------------------------------------------------------------------
  * "THE BEER-WARE LICENSE" (Revision 42):
  * <phk@FreeBSD.ORG> wrote this file.  As long as you retain this notice you
  * can do whatever you want with this stuff. If we meet some day, and you think
  * this stuff is worth it, you can buy me a beer in return.   Poul-Henning Kamp
  * ---------------------------------------------------------------------------
  */
 /*
  * https://papers.freebsd.org/2002/phk-timecounters.files/timecounter.pdf
  */
 #include <sys/cdefs.h>
 /* __FBSDID("$FreeBSD: src/sys/kern/kern_tc.c,v 1.166 2005/09/19 22:16:31 andre Exp $"); */
-__KERNEL_RCSID(0, "$NetBSD: kern_tc.c,v 1.74 2023/07/27 01:48:49 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_tc.c,v 1.75 2023/07/28 10:37:28 riastradh Exp $");
 #ifdef _KERNEL_OPT
 #include "opt_ntp.h"
 #endif
 #include <sys/param.h>
 #include <sys/atomic.h>
 #include <sys/evcnt.h>
 #include <sys/kauth.h>
 #include <sys/kernel.h>
 #include <sys/lock.h>
 #include <sys/mutex.h>
 #include <sys/reboot.h>	/* XXX just to get AB_VERBOSE */
 #include <sys/sysctl.h>
 #include <sys/syslog.h>
 #include <sys/systm.h>
 #include <sys/timepps.h>
 #include <sys/timetc.h>
 #include <sys/timex.h>
 #include <sys/xcall.h>
 /*
  * A large step happens on boot.  This constant detects such steps.
  * It is relatively small so that ntp_update_second gets called enough
  * in the typical 'missed a couple of seconds' case, but doesn't loop
  * forever when the time step is large.
  */
 #define LARGE_STEP	200
 /*
  * Implement a dummy timecounter which we can use until we get a real one
  * in the air.  This allows the console and other early stuff to use
  * time services.
  */
 static u_int
 dummy_get_timecount(struct timecounter *tc)
+{
 	static u_int now;
 	return ++now;
+}
 static struct timecounter dummy_timecounter = {
 	.tc_get_timecount	= dummy_get_timecount,
 	.tc_counter_mask	= ~0u,
 	.tc_frequency		= 1000000,
 	.tc_name		= "dummy",
 	.tc_quality		= -1000000,
 	.tc_priv		= NULL,
 };
 struct timehands {
 	/* These fields must be initialized by the driver. */
 	struct timecounter	*th_counter;     /* active timecounter */
 	int64_t			th_adjustment;   /* frequency adjustment */
 						 /* (NTP/adjtime) */
 	uint64_t		th_scale;        /* scale factor (counter */
 						 /* tick->time) */
 	uint64_t 		th_offset_count; /* offset at last time */
 						 /* update (tc_windup()) */
 	struct bintime		th_offset;       /* bin (up)time at windup */
 	struct timeval		th_microtime;    /* cached microtime */
 	struct timespec		th_nanotime;     /* cached nanotime */
 	/* Fields not to be copied in tc_windup start with th_generation. */
 	volatile u_int		th_generation;   /* current genration */
 	struct timehands	*th_next;        /* next timehand */
 };
 static struct timehands th0;
 static struct timehands th9 = { .th_next = &th0, };
 static struct timehands th8 = { .th_next = &th9, };
 static struct timehands th7 = { .th_next = &th8, };
 static struct timehands th6 = { .th_next = &th7, };
 static struct timehands th5 = { .th_next = &th6, };
 static struct timehands th4 = { .th_next = &th5, };
 static struct timehands th3 = { .th_next = &th4, };
 static struct timehands th2 = { .th_next = &th3, };
 static struct timehands th1 = { .th_next = &th2, };
 static struct timehands th0 = {
 	.th_counter = &dummy_timecounter,
 	.th_scale = (uint64_t)-1 / 1000000,
 	.th_offset = { .sec = 1, .frac = 0 },
 	.th_generation = 1,
 	.th_next = &th1,
 };
 static struct timehands *volatile timehands = &th0;
 struct timecounter *timecounter = &dummy_timecounter;
 static struct timecounter *timecounters = &dummy_timecounter;
 /* used by savecore(8) */
 time_t time_second_legacy asm("time_second");
 #ifdef __HAVE_ATOMIC64_LOADSTORE
 volatile time_t time__second __cacheline_aligned = 1;
 volatile time_t time__uptime __cacheline_aligned = 1;
 #else
 static volatile struct {
 	uint32_t lo, hi;
 } time__uptime32 __cacheline_aligned = {
 	.lo = 1,
 }, time__second32 __cacheline_aligned = {
 	.lo = 1,
 };
 #endif
 static struct {
 	struct bintime bin;
 	volatile unsigned gen;	/* even when stable, odd when changing */
 } timebase __cacheline_aligned;
 static int timestepwarnings;
 kmutex_t timecounter_lock;
 static u_int timecounter_mods;
 static volatile int timecounter_removals = 1;
 static u_int timecounter_bad;
 #ifdef __HAVE_ATOMIC64_LOADSTORE
 static inline void
 setrealuptime(time_t second, time_t uptime)
+{
 	time_second_legacy = second;
 	atomic_store_relaxed(&time__second, second);
 	atomic_store_relaxed(&time__uptime, uptime);
+}
 #else
 static inline void
 setrealuptime(time_t second, time_t uptime)
+{
 	uint32_t seclo = second & 0xffffffff, sechi = second >> 32;
 	uint32_t uplo = uptime & 0xffffffff, uphi = uptime >> 32;
 	KDASSERT(mutex_owned(&timecounter_lock));
 	time_second_legacy = second;
 	/*
 	 * Fast path -- no wraparound, just updating the low bits, so
 	 * no need for seqlocked access.
 	 */
 	if (__predict_true(sechi == time__second32.hi) &&
 	    __predict_true(uphi == time__uptime32.hi)) {
 		atomic_store_relaxed(&time__second32.lo, seclo);
 		atomic_store_relaxed(&time__uptime32.lo, uplo);
 		return;
+	}
 	atomic_store_relaxed(&time__second32.hi, 0xffffffff);
 	atomic_store_relaxed(&time__uptime32.hi, 0xffffffff);
 	membar_producer();
 	atomic_store_relaxed(&time__second32.lo, seclo);
 	atomic_store_relaxed(&time__uptime32.lo, uplo);
 	membar_producer();
 	atomic_store_relaxed(&time__second32.hi, sechi);
 	atomic_store_relaxed(&time__uptime32.hi, uphi);
+}
 time_t
 getrealtime(void)
+{
 	uint32_t lo, hi;
 	do {
 		for (;;) {
 			hi = atomic_load_relaxed(&time__second32.hi);
 			if (__predict_true(hi != 0xffffffff))
 				break;
 			SPINLOCK_BACKOFF_HOOK;
+		}
 		membar_consumer();
 		lo = atomic_load_relaxed(&time__second32.lo);
 		membar_consumer();
 	} while (hi != atomic_load_relaxed(&time__second32.hi));
 	return ((time_t)hi << 32) | lo;
+}
 time_t
 getuptime(void)
+{
 	uint32_t lo, hi;
 	do {
 		for (;;) {
 			hi = atomic_load_relaxed(&time__uptime32.hi);
 			if (__predict_true(hi != 0xffffffff))
 				break;
 			SPINLOCK_BACKOFF_HOOK;
+		}
 		membar_consumer();
 		lo = atomic_load_relaxed(&time__uptime32.lo);
 		membar_consumer();
 	} while (hi != atomic_load_relaxed(&time__uptime32.hi));
 	return ((time_t)hi << 32) | lo;
+}
 time_t
 getboottime(void)
+{
 	return getrealtime() - getuptime();
+}
 uint32_t
 getuptime32(void)
+{
 	return atomic_load_relaxed(&time__uptime32.lo);
+}
 #endif	/* !defined(__HAVE_ATOMIC64_LOADSTORE) */
 /*
  * sysctl helper routine for kern.timercounter.hardware
  */
 static int
 sysctl_kern_timecounter_hardware(SYSCTLFN_ARGS)
+{
 	struct sysctlnode node;
 	int error;
 	char newname[MAX_TCNAMELEN];
 	struct timecounter *newtc, *tc;
 	tc = timecounter;
 	strlcpy(newname, tc->tc_name, sizeof(newname));
 	node = *rnode;
 	node.sysctl_data = newname;
 	node.sysctl_size = sizeof(newname);
 	error = sysctl_lookup(SYSCTLFN_CALL(&node));
 	if (error ||
 	    newp == NULL ||
 	    strncmp(newname, tc->tc_name, sizeof(newname)) == 0)
 		return error;
 	if (l != NULL && (error = kauth_authorize_system(l->l_cred,
 	    KAUTH_SYSTEM_TIME, KAUTH_REQ_SYSTEM_TIME_TIMECOUNTERS, newname,
 	    NULL, NULL)) != 0)
 		return error;
 	if (!cold)
 		mutex_spin_enter(&timecounter_lock);
 	error = EINVAL;
 	for (newtc = timecounters; newtc != NULL; newtc = newtc->tc_next) {
 		if (strcmp(newname, newtc->tc_name) != 0)
 			continue;
 		/* Warm up new timecounter. */
 		(void)newtc->tc_get_timecount(newtc);
 		(void)newtc->tc_get_timecount(newtc);
 		timecounter = newtc;
 		error = 0;
 		break;
+	}
 	if (!cold)
 		mutex_spin_exit(&timecounter_lock);
 	return error;
+}
 static int
 sysctl_kern_timecounter_choice(SYSCTLFN_ARGS)
+{
 	char buf[MAX_TCNAMELEN+48];
 	char *where;
 	const char *spc;
 	struct timecounter *tc;
 	size_t needed, left, slen;
 	int error, mods;
 	if (newp != NULL)
 		return EPERM;
 	if (namelen != 0)
 		return EINVAL;
 	mutex_spin_enter(&timecounter_lock);
  retry:
 	spc = "";
 	error = 0;
 	needed = 0;
 	left = *oldlenp;
 	where = oldp;
 	for (tc = timecounters; error == 0 && tc != NULL; tc = tc->tc_next) {
 		if (where == NULL) {
 			needed += sizeof(buf);  /* be conservative */
 		} else {
 			slen = snprintf(buf, sizeof(buf), "%s%s(q=%d, f=%" PRId64
 					" Hz)", spc, tc->tc_name, tc->tc_quality,
 					tc->tc_frequency);
 			if (left < slen + 1)
 				break;
 		 	mods = timecounter_mods;
 			mutex_spin_exit(&timecounter_lock);
 			error = copyout(buf, where, slen + 1);
 			mutex_spin_enter(&timecounter_lock);
 			if (mods != timecounter_mods) {
 				goto retry;
+			}
 			spc = " ";
 			where += slen;
 			needed += slen;
 			left -= slen;
+		}
+	}
 	mutex_spin_exit(&timecounter_lock);
 	*oldlenp = needed;
 	return error;
+}
 SYSCTL_SETUP(sysctl_timecounter_setup, "sysctl timecounter setup")
+{
 	const struct sysctlnode *node;
 	sysctl_createv(clog, 0, NULL, &node,
 		       CTLFLAG_PERMANENT,
 		       CTLTYPE_NODE, "timecounter",
 		       SYSCTL_DESCR("time counter information"),
 		       NULL, 0, NULL, 0,
 		       CTL_KERN, CTL_CREATE, CTL_EOL);
 	if (node != NULL) {
 		sysctl_createv(clog, 0, NULL, NULL,
 			       CTLFLAG_PERMANENT,
 			       CTLTYPE_STRING, "choice",
 			       SYSCTL_DESCR("available counters"),
 			       sysctl_kern_timecounter_choice, 0, NULL, 0,
 			       CTL_KERN, node->sysctl_num, CTL_CREATE, CTL_EOL);
 		sysctl_createv(clog, 0, NULL, NULL,
 			       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
 			       CTLTYPE_STRING, "hardware",
 			       SYSCTL_DESCR("currently active time counter"),
 			       sysctl_kern_timecounter_hardware, 0, NULL, MAX_TCNAMELEN,
 			       CTL_KERN, node->sysctl_num, CTL_CREATE, CTL_EOL);
 		sysctl_createv(clog, 0, NULL, NULL,
 			       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
 			       CTLTYPE_INT, "timestepwarnings",
 			       SYSCTL_DESCR("log time steps"),
 			       NULL, 0, &timestepwarnings, 0,
 			       CTL_KERN, node->sysctl_num, CTL_CREATE, CTL_EOL);
+	}
+}
 #ifdef TC_COUNTERS
 #define	TC_STATS(name)							\
 static struct evcnt n##name =						\
     EVCNT_INITIALIZER(EVCNT_TYPE_MISC, NULL, "timecounter", #name);	\
 EVCNT_ATTACH_STATIC(n##name)
 TC_STATS(binuptime);    TC_STATS(nanouptime);    TC_STATS(microuptime);
 TC_STATS(bintime);      TC_STATS(nanotime);      TC_STATS(microtime);
 TC_STATS(getbinuptime); TC_STATS(getnanouptime); TC_STATS(getmicrouptime);
 TC_STATS(getbintime);   TC_STATS(getnanotime);   TC_STATS(getmicrotime);
 TC_STATS(setclock);
 #define	TC_COUNT(var)	var.ev_count++
 #undef TC_STATS
 #else
 #define	TC_COUNT(var)	/* nothing */
 #endif	/* TC_COUNTERS */
 static void tc_windup(void);
 /*
  * Return the difference between the timehands' counter value now and what
  * was when we copied it to the timehands' offset_count.
  */
 static inline u_int
 tc_delta(struct timehands *th)
+{
 	struct timecounter *tc;
 	tc = th->th_counter;
 	return (tc->tc_get_timecount(tc) -
 		 th->th_offset_count) & tc->tc_counter_mask;
+}
 /*
  * Functions for reading the time.  We have to loop until we are sure that
  * the timehands that we operated on was not updated under our feet.  See
  * the comment in <sys/timevar.h> for a description of these 12 functions.
  */
 void
 binuptime(struct bintime *bt)
+{
 	struct timehands *th;
 	lwp_t *l;
 	u_int lgen, gen;
 	TC_COUNT(nbinuptime);
 	/*
 	 * Provide exclusion against tc_detach().
+	 *
 	 * We record the number of timecounter removals before accessing
 	 * timecounter state.  Note that the LWP can be using multiple
 	 * "generations" at once, due to interrupts (interrupted while in
 	 * this function).  Hardware interrupts will borrow the interrupted
 	 * LWP's l_tcgen value for this purpose, and can themselves be
 	 * interrupted by higher priority interrupts.  In this case we need
 	 * to ensure that the oldest generation in use is recorded.
+	 *
 	 * splsched() is too expensive to use, so we take care to structure
 	 * this code in such a way that it is not required.  Likewise, we
 	 * do not disable preemption.
+	 *
 	 * Memory barriers are also too expensive to use for such a
 	 * performance critical function.  The good news is that we do not
 	 * need memory barriers for this type of exclusion, as the thread
 	 * updating timecounter_removals will issue a broadcast cross call
 	 * before inspecting our l_tcgen value (this elides memory ordering
 	 * issues).
+	 *
 	 * XXX If the author of the above comment knows how to make it
 	 * safe to avoid memory barriers around the access to
 	 * th->th_generation, I'm all ears.
 	 */
 	l = curlwp;
 	lgen = l->l_tcgen;
 	if (__predict_true(lgen == 0)) {
 		l->l_tcgen = timecounter_removals;
+	}
 	__insn_barrier();
 	do {
 		th = atomic_load_consume(&timehands);
 		gen = th->th_generation;
 		membar_consumer();
 		*bt = th->th_offset;
 		bintime_addx(bt, th->th_scale * tc_delta(th));
 		membar_consumer();
 	} while (gen == 0 || gen != th->th_generation);
 	__insn_barrier();
 	l->l_tcgen = lgen;
+}
 void
 nanouptime(struct timespec *tsp)
+{
 	struct bintime bt;
 	TC_COUNT(nnanouptime);
 	binuptime(&bt);
 	bintime2timespec(&bt, tsp);
+}
 void
 microuptime(struct timeval *tvp)
+{
 	struct bintime bt;
 	TC_COUNT(nmicrouptime);
 	binuptime(&bt);
 	bintime2timeval(&bt, tvp);
+}
 void
 bintime(struct bintime *bt)
+{
 	struct bintime boottime;
 	TC_COUNT(nbintime);
 	binuptime(bt);
 	getbinboottime(&boottime);
 	bintime_add(bt, &boottime);
+}
 void
 nanotime(struct timespec *tsp)
+{
 	struct bintime bt;
 	TC_COUNT(nnanotime);
 	bintime(&bt);
 	bintime2timespec(&bt, tsp);
+}
 void
 microtime(struct timeval *tvp)
+{
 	struct bintime bt;
 	TC_COUNT(nmicrotime);
 	bintime(&bt);
 	bintime2timeval(&bt, tvp);
+}
 void
 getbinuptime(struct bintime *bt)
+{
 	struct timehands *th;
 	u_int gen;
 	TC_COUNT(ngetbinuptime);
 	do {
 		th = atomic_load_consume(&timehands);
 		gen = th->th_generation;
 		membar_consumer();
 		*bt = th->th_offset;
 		membar_consumer();
 	} while (gen == 0 || gen != th->th_generation);
+}
 void
 getnanouptime(struct timespec *tsp)
+{
 	struct timehands *th;
 	u_int gen;
 	TC_COUNT(ngetnanouptime);
 	do {
 		th = atomic_load_consume(&timehands);
 		gen = th->th_generation;
 		membar_consumer();
 		bintime2timespec(&th->th_offset, tsp);
 		membar_consumer();
 	} while (gen == 0 || gen != th->th_generation);
+}
 void
 getmicrouptime(struct timeval *tvp)
+{
 	struct timehands *th;
 	u_int gen;
 	TC_COUNT(ngetmicrouptime);
 	do {
 		th = atomic_load_consume(&timehands);
 		gen = th->th_generation;
 		membar_consumer();
 		bintime2timeval(&th->th_offset, tvp);
 		membar_consumer();
 	} while (gen == 0 || gen != th->th_generation);
+}
 void
 getbintime(struct bintime *bt)
+{
 	struct timehands *th;
 	struct bintime boottime;
 	u_int gen;
 	TC_COUNT(ngetbintime);
 	do {
 		th = atomic_load_consume(&timehands);
 		gen = th->th_generation;
 		membar_consumer();
 		*bt = th->th_offset;
 		membar_consumer();
 	} while (gen == 0 || gen != th->th_generation);
 	getbinboottime(&boottime);
 	bintime_add(bt, &boottime);
+}
 static inline void
 dogetnanotime(struct timespec *tsp)
+{
 	struct timehands *th;
 	u_int gen;
 	TC_COUNT(ngetnanotime);
 	do {
 		th = atomic_load_consume(&timehands);
 		gen = th->th_generation;
 		membar_consumer();
 		*tsp = th->th_nanotime;
 		membar_consumer();
 	} while (gen == 0 || gen != th->th_generation);
+}
 void
 getnanotime(struct timespec *tsp)
+{
 	dogetnanotime(tsp);
+}
 void dtrace_getnanotime(struct timespec *tsp);
 void
 dtrace_getnanotime(struct timespec *tsp)
+{
 	dogetnanotime(tsp);
+}
 void
 getmicrotime(struct timeval *tvp)
+{
 	struct timehands *th;
 	u_int gen;
 	TC_COUNT(ngetmicrotime);
 	do {
 		th = atomic_load_consume(&timehands);
 		gen = th->th_generation;
 		membar_consumer();
 		*tvp = th->th_microtime;
 		membar_consumer();
 	} while (gen == 0 || gen != th->th_generation);
+}
 void
 getnanoboottime(struct timespec *tsp)
+{
 	struct bintime bt;
 	getbinboottime(&bt);
 	bintime2timespec(&bt, tsp);
+}
 void
 getmicroboottime(struct timeval *tvp)
+{
 	struct bintime bt;
 	getbinboottime(&bt);
 	bintime2timeval(&bt, tvp);
+}
 void
 getbinboottime(struct bintime *basep)
+{
 	struct bintime base;
 	unsigned gen;
 	do {
 		/* Spin until the timebase isn't changing.  */
 		while ((gen = atomic_load_relaxed(&timebase.gen)) & 1)
 			SPINLOCK_BACKOFF_HOOK;
 		/* Read out a snapshot of the timebase.  */
 		membar_consumer();
 		base = timebase.bin;
 		membar_consumer();
 		/* Restart if it changed while we were reading.  */
 	} while (gen != atomic_load_relaxed(&timebase.gen));
 	*basep = base;
+}
 /*
  * Initialize a new timecounter and possibly use it.
  */
 void
 tc_init(struct timecounter *tc)
+{
 	u_int u;
 	KASSERTMSG(tc->tc_next == NULL, "timecounter %s already initialised",
 	    tc->tc_name);
 	u = tc->tc_frequency / tc->tc_counter_mask;
 	/* XXX: We need some margin here, 10% is a guess */
 	u *= 11;
 	u /= 10;
 	if (u > hz && tc->tc_quality >= 0) {
 		tc->tc_quality = -2000;
 		aprint_verbose(
 		    "timecounter: Timecounter \"%s\" frequency %ju Hz",
 			    tc->tc_name, (uintmax_t)tc->tc_frequency);
 		aprint_verbose(" -- Insufficient hz, needs at least %u\n", u);
 	} else if (tc->tc_quality >= 0 || bootverbose) {
 		aprint_verbose(
 		    "timecounter: Timecounter \"%s\" frequency %ju Hz "
 		    "quality %d\n", tc->tc_name, (uintmax_t)tc->tc_frequency,
 		    tc->tc_quality);
+	}
 	mutex_spin_enter(&timecounter_lock);
 	tc->tc_next = timecounters;
 	timecounters = tc;
 	timecounter_mods++;
 	/*
 	 * Never automatically use a timecounter with negative quality.
 	 * Even though we run on the dummy counter, switching here may be
 	 * worse since this timecounter may not be monotonous.
 	 */
 	if (tc->tc_quality >= 0 && (tc->tc_quality > timecounter->tc_quality ||
 	    (tc->tc_quality == timecounter->tc_quality &&
 	    tc->tc_frequency > timecounter->tc_frequency))) {
 		(void)tc->tc_get_timecount(tc);
 		(void)tc->tc_get_timecount(tc);
 		timecounter = tc;
 		tc_windup();
+	}
 	mutex_spin_exit(&timecounter_lock);
+}
 /*
  * Pick a new timecounter due to the existing counter going bad.
  */
 static void
 tc_pick(void)
+{
 	struct timecounter *best, *tc;
 	KASSERT(mutex_owned(&timecounter_lock));
 	for (best = tc = timecounters; tc != NULL; tc = tc->tc_next) {
 		if (tc->tc_quality > best->tc_quality)
 			best = tc;
 		else if (tc->tc_quality < best->tc_quality)
 			continue;
 		else if (tc->tc_frequency > best->tc_frequency)
 			best = tc;
+	}
 	(void)best->tc_get_timecount(best);
 	(void)best->tc_get_timecount(best);
 	timecounter = best;
+}
 /*
  * A timecounter has gone bad, arrange to pick a new one at the next
  * clock tick.
  */
 void
 tc_gonebad(struct timecounter *tc)
+{
 	tc->tc_quality = -100;
 	membar_producer();
 	atomic_inc_uint(&timecounter_bad);
+}
 /*
  * Stop using a timecounter and remove it from the timecounters list.
  */
 int
 tc_detach(struct timecounter *target)
+{
 	struct timecounter *tc;
 	struct timecounter **tcp = NULL;
 	int removals;
 	lwp_t *l;
 	/* First, find the timecounter. */
 	mutex_spin_enter(&timecounter_lock);
 	for (tcp = &timecounters, tc = timecounters;
 	     tc != NULL;
 	     tcp = &tc->tc_next, tc = tc->tc_next) {
 		if (tc == target)
 			break;
+	}
 	if (tc == NULL) {
 		mutex_spin_exit(&timecounter_lock);
 		return ESRCH;
+	}
 	/* And now, remove it. */
 	*tcp = tc->tc_next;
 	if (timecounter == target) {
 		tc_pick();
 		tc_windup();
+	}
 	timecounter_mods++;
 	removals = timecounter_removals++;
 	mutex_spin_exit(&timecounter_lock);
 	/*
 	 * We now have to determine if any threads in the system are still
 	 * making use of this timecounter.
+	 *
 	 * We issue a broadcast cross call to elide memory ordering issues,
 	 * then scan all LWPs in the system looking at each's timecounter
 	 * generation number.  We need to see a value of zero (not actively
 	 * using a timecounter) or a value greater than our removal value.
+	 *
 	 * We may race with threads that read `timecounter_removals' and
 	 * and then get preempted before updating `l_tcgen'.  This is not
 	 * a problem, since it means that these threads have not yet started
 	 * accessing timecounter state.  All we do need is one clean
 	 * snapshot of the system where every thread appears not to be using
 	 * old timecounter state.
 	 */
 	for (;;) {
 		xc_barrier(0);
 		mutex_enter(&proc_lock);
 		LIST_FOREACH(l, &alllwp, l_list) {
 			if (l->l_tcgen == 0 || l->l_tcgen > removals) {
 				/*
 				 * Not using timecounter or old timecounter
 				 * state at time of our xcall or later.
 				 */
 				continue;
+			}
 			break;
+		}
 		mutex_exit(&proc_lock);
 		/*
 		 * If the timecounter is still in use, wait at least 10ms
 		 * before retrying.
 		 */
 		if (l == NULL) {
 			break;
+		}
 		(void)kpause("tcdetach", false, mstohz(10), NULL);
+	}
 	tc->tc_next = NULL;
 	return 0;
+}
 /* Report the frequency of the current timecounter. */
 uint64_t
 tc_getfrequency(void)
+{
 	return atomic_load_consume(&timehands)->th_counter->tc_frequency;
+}
 /*
  * Step our concept of UTC.  This is done by modifying our estimate of
  * when we booted.
  */
 void
 tc_setclock(const struct timespec *ts)
+{
 	struct timespec ts2;
 	struct bintime bt, bt2;
 	mutex_spin_enter(&timecounter_lock);
 	TC_COUNT(nsetclock);
 	binuptime(&bt2);
 	timespec2bintime(ts, &bt);
 	bintime_sub(&bt, &bt2);
 	bintime_add(&bt2, &timebase.bin);
 	timebase.gen |= 1;	/* change in progress */
 	membar_producer();
 	timebase.bin = bt;
 	membar_producer();
 	timebase.gen++;		/* commit change */
 	tc_windup();
 	mutex_spin_exit(&timecounter_lock);
 	if (timestepwarnings) {
 		bintime2timespec(&bt2, &ts2);
 		log(LOG_INFO,
 		    "Time stepped from %lld.%09ld to %lld.%09ld\n",
 		    (long long)ts2.tv_sec, ts2.tv_nsec,
 		    (long long)ts->tv_sec, ts->tv_nsec);
+	}
+}
 /*
  * Initialize the next struct timehands in the ring and make
  * it the active timehands.  Along the way we might switch to a different
  * timecounter and/or do seconds processing in NTP.  Slightly magic.
  */
 static void
 tc_windup(void)
+{
 	struct bintime bt;
 	struct timehands *th, *tho;
 	uint64_t scale;
 	u_int delta, ncount, ogen;
 	int i, s_update;
 	time_t t;
 	KASSERT(mutex_owned(&timecounter_lock));
 	s_update = 0;
 	/*
 	 * Make the next timehands a copy of the current one, but do not
 	 * overwrite the generation or next pointer.  While we update
 	 * the contents, the generation must be zero.  Ensure global
 	 * visibility of the generation before proceeding.
 	 */
 	tho = timehands;
 	th = tho->th_next;
 	ogen = th->th_generation;
 	th->th_generation = 0;
 	membar_producer();
 	bcopy(tho, th, offsetof(struct timehands, th_generation));
 	/*
 	 * Capture a timecounter delta on the current timecounter and if
 	 * changing timecounters, a counter value from the new timecounter.
 	 * Update the offset fields accordingly.
 	 */
 	delta = tc_delta(th);
 	if (th->th_counter != timecounter)
 		ncount = timecounter->tc_get_timecount(timecounter);
 	else
 		ncount = 0;
 	th->th_offset_count += delta;
 	bintime_addx(&th->th_offset, th->th_scale * delta);
 	/*
 	 * Hardware latching timecounters may not generate interrupts on
 	 * PPS events, so instead we poll them.  There is a finite risk that
 	 * the hardware might capture a count which is later than the one we
 	 * got above, and therefore possibly in the next NTP second which might
 	 * have a different rate than the current NTP second.  It doesn't
 	 * matter in practice.
 	 */
 	if (tho->th_counter->tc_poll_pps)
 		tho->th_counter->tc_poll_pps(tho->th_counter);
 	/*
 	 * Deal with NTP second processing.  The for loop normally
 	 * iterates at most once, but in extreme situations it might
 	 * keep NTP sane if timeouts are not run for several seconds.
 	 * At boot, the time step can be large when the TOD hardware
 	 * has been read, so on really large steps, we call
 	 * ntp_update_second only twice.  We need to call it twice in
 	 * case we missed a leap second.
 	 * If NTP is not compiled in ntp_update_second still calculates
 	 * the adjustment resulting from adjtime() calls.
 	 */
 	bt = th->th_offset;
 	bintime_add(&bt, &timebase.bin);
 	i = bt.sec - tho->th_microtime.tv_sec;
 	if (i > LARGE_STEP)
 		i = 2;
 	for (; i > 0; i--) {
 		t = bt.sec;
 		ntp_update_second(&th->th_adjustment, &bt.sec);
 		s_update = 1;
 		if (bt.sec != t) {
 			timebase.gen |= 1;	/* change in progress */
 			membar_producer();
 			timebase.bin.sec += bt.sec - t;
 			membar_producer();
 			timebase.gen++;		/* commit change */
+		}
+	}
 	/* Update the UTC timestamps used by the get*() functions. */
 	/* XXX shouldn't do this here.  Should force non-`get' versions. */
 	bintime2timeval(&bt, &th->th_microtime);
 	bintime2timespec(&bt, &th->th_nanotime);
 	/* Now is a good time to change timecounters. */
 	if (th->th_counter != timecounter) {
 		th->th_counter = timecounter;
 		th->th_offset_count = ncount;
 		s_update = 1;
+	}
 	/*-
 	 * Recalculate the scaling factor.  We want the number of 1/2^64
 	 * fractions of a second per period of the hardware counter, taking
 	 * into account the th_adjustment factor which the NTP PLL/adjtime(2)
 	 * processing provides us with.
+	 *
 	 * The th_adjustment is nanoseconds per second with 32 bit binary
 	 * fraction and we want 64 bit binary fraction of second:
+	 *
 	 *	 x = a * 2^32 / 10^9 = a * 4.294967296
+	 *
 	 * The range of th_adjustment is +/- 5000PPM so inside a 64bit int
 	 * we can only multiply by about 850 without overflowing, but that
 	 * leaves suitably precise fractions for multiply before divide.
+	 *
 	 * Divide before multiply with a fraction of 2199/512 results in a
 	 * systematic undercompensation of 10PPM of th_adjustment.  On a
 	 * 5000PPM adjustment this is a 0.05PPM error.  This is acceptable.
+ 	 *
 	 * We happily sacrifice the lowest of the 64 bits of our result
 	 * to the goddess of code clarity.
+	 *
 	 */
 	if (s_update) {
 		scale = (uint64_t)1 << 63;
 		scale += (th->th_adjustment / 1024) * 2199;
 		scale /= th->th_counter->tc_frequency;
 		th->th_scale = scale * 2;
+	}
 	/*
 	 * Now that the struct timehands is again consistent, set the new
 	 * generation number, making sure to not make it zero.  Ensure
 	 * changes are globally visible before changing.
 	 */
 	if (++ogen == 0)
 		ogen = 1;
 	membar_producer();
 	th->th_generation = ogen;
 	/*
 	 * Go live with the new struct timehands.  Ensure changes are
 	 * globally visible before changing.
 	 */
 	setrealuptime(th->th_microtime.tv_sec, th->th_offset.sec);