From 11d1f9b2143325c151ff5de652177687515961c9 Mon Sep 17 00:00:00 2001
From: cheloha <cheloha@openbsd.org>
Date: Wed, 23 Aug 2023 01:55:45 +0000
Subject: [PATCH] all platforms: separate cpu_initclocks() from
 cpu_startclock()

To give the primary CPU an opportunity to perform clock interrupt
preparation in a machine-independent manner we need to separate the
"initialization" parts of cpu_initclocks() from the "start the clock
interrupt" parts.  Currently, cpu_initclocks() does everything all at
once, so there is no space for this MI setup.

Many platforms have more-or-less already done this separation by
implementing a separate routine named "cpu_startclock()".  This patch
promotes cpu_startclock() from de facto standard to mandatory API.

- Prototype cpu_startclock() in sys/systm.h alongside cpu_initclocks().
  The separation of responsibility between the two routines is a bit
  fuzzy but the basic guidelines are as follows:

  + cpu_initclocks() must initialize hz, stathz, and profhz, and call
    clockintr_init().

  + cpu_startclock() must call clockintr_cpu_init() and start the clock
    interrupt cycle on the calling CPU.

  These guidelines will shift in the future, but that's the way things
  stand as of *this* commit.

- In initclocks(): first call cpu_initclocks(), then do MI setup, and
  last call cpu_startclock().

- On platforms where cpu_startclock() already exists: don't call
  cpu_startclock() from cpu_initclocks() anymore.

- On platforms where cpu_startclock() doesn't yet exist: implement it.
  Usually this is as simple as dividing cpu_initclocks() in two.

Tested on amd64 (i8254, lapic), arm64, i386 (i8254, lapic), macppc,
mips64/octeon, and sparc64.  Tested on arm/armv7 (agtimer(4)) by
phessler@ and jmatthew@.  Tested on m88k/luna88k by aoyama@.  Tested
on powerpc64 by gkoehler@ and mlarkin@.  Tested on riscv64 by
jmatthew@.

Thread: https://marc.info/?l=openbsd-tech&m=169195251322149&w=2
---
 sys/arch/alpha/alpha/clock.c            |  6 +++++-
 sys/arch/amd64/amd64/lapic.c            |  5 ++---
 sys/arch/amd64/amd64/machdep.c          |  9 ++++++++-
 sys/arch/amd64/include/cpu.h            |  6 ++++--
 sys/arch/amd64/isa/clock.c              |  6 +++++-
 sys/arch/arm/cortex/agtimer.c           | 13 +------------
 sys/arch/arm/cortex/amptimer.c          |  6 +-----
 sys/arch/arm/include/cpu.h              |  4 +---
 sys/arch/arm64/dev/agtimer.c            | 21 +++------------------
 sys/arch/arm64/include/cpu.h            |  3 +--
 sys/arch/armv7/omap/dmtimer.c           |  9 +++++++--
 sys/arch/armv7/omap/gptimer.c           |  9 +++++++--
 sys/arch/armv7/sunxi/sxitimer.c         |  9 +++++++--
 sys/arch/hppa/dev/clock.c               |  4 +---
 sys/arch/hppa/include/cpu.h             |  3 +--
 sys/arch/i386/i386/lapic.c              |  5 ++---
 sys/arch/i386/i386/machdep.c            |  9 ++++++++-
 sys/arch/i386/include/cpu.h             |  7 +++++--
 sys/arch/i386/isa/clock.c               |  6 +++++-
 sys/arch/luna88k/luna88k/clock.c        |  6 +++++-
 sys/arch/macppc/macppc/clock.c          |  8 ++------
 sys/arch/mips64/include/cpu.h           |  3 ++-
 sys/arch/mips64/mips64/clock.c          | 20 ++++++++++++++------
 sys/arch/mips64/mips64/mips64_machdep.c | 12 ++++++++++--
 sys/arch/powerpc64/include/cpu.h        |  3 +--
 sys/arch/powerpc64/powerpc64/clock.c    |  6 +-----
 sys/arch/riscv64/include/cpu.h          |  3 +--
 sys/arch/riscv64/riscv64/clock.c        |  5 +----
 sys/arch/sh/sh/clock.c                  |  6 +++++-
 sys/arch/sparc64/sparc64/clock.c        |  6 +++++-
 sys/kern/kern_clock.c                   |  5 ++++-
 sys/sys/systm.h                         |  3 ++-
 32 files changed, 127 insertions(+), 99 deletions(-)

diff --git a/sys/arch/alpha/alpha/clock.c b/sys/arch/alpha/alpha/clock.c
index c03cd35993d..dd3ad3f75b2 100644
--- a/sys/arch/alpha/alpha/clock.c
+++ b/sys/arch/alpha/alpha/clock.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: clock.c,v 1.29 2023/08/21 15:19:09 cheloha Exp $	*/
+/*	$OpenBSD: clock.c,v 1.30 2023/08/23 01:55:45 cheloha Exp $	*/
 /*	$NetBSD: clock.c,v 1.29 2000/06/05 21:47:10 thorpej Exp $	*/
 
 /*
@@ -192,7 +192,11 @@ cpu_initclocks(void)
 	stathz = hz;
 	profhz = stathz;
 	clockintr_init(0);
+}
 
+void
+cpu_startclock(void)
+{
 	clockintr_cpu_init(NULL);
 
 	/*
diff --git a/sys/arch/amd64/amd64/lapic.c b/sys/arch/amd64/amd64/lapic.c
index da17b0875f7..4e7182ecb5e 100644
--- a/sys/arch/amd64/amd64/lapic.c
+++ b/sys/arch/amd64/amd64/lapic.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: lapic.c,v 1.68 2023/04/26 10:52:55 mlarkin Exp $	*/
+/*	$OpenBSD: lapic.c,v 1.69 2023/08/23 01:55:46 cheloha Exp $	*/
 /* $NetBSD: lapic.c,v 1.2 2003/05/08 01:04:35 fvdl Exp $ */
 
 /*-
@@ -499,8 +499,6 @@ lapic_initclocks(void)
 	stathz = hz;
 	profhz = stathz * 10;
 	clockintr_init(CL_RNDSTAT);
-
-	lapic_startclock();
 }
 
 
@@ -599,6 +597,7 @@ skip_calibration:
 	    lapic_per_second * (1ULL << 32) / 1000000000;
 	lapic_timer_nsec_max = UINT64_MAX / lapic_timer_nsec_cycle_ratio;
 	initclock_func = lapic_initclocks;
+	startclock_func = lapic_startclock;
 }
 
 /*
diff --git a/sys/arch/amd64/amd64/machdep.c b/sys/arch/amd64/amd64/machdep.c
index 453de13fbfb..8c5f398b88c 100644
--- a/sys/arch/amd64/amd64/machdep.c
+++ b/sys/arch/amd64/amd64/machdep.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: machdep.c,v 1.286 2023/07/27 00:28:25 guenther Exp $	*/
+/*	$OpenBSD: machdep.c,v 1.287 2023/08/23 01:55:45 cheloha Exp $	*/
 /*	$NetBSD: machdep.c,v 1.3 2003/05/07 22:58:18 fvdl Exp $	*/
 
 /*-
@@ -227,6 +227,7 @@ paddr_t avail_end;
 
 void (*delay_func)(int) = i8254_delay;
 void (*initclock_func)(void) = i8254_initclocks;
+void (*startclock_func)(void) = i8254_start_both_clocks;
 
 /*
  * Format of boot information passed to us by 32-bit /boot
@@ -1880,6 +1881,12 @@ cpu_initclocks(void)
 	(*initclock_func)();
 }
 
+void
+cpu_startclock(void)
+{
+	(*startclock_func)();
+}
+
 void
 need_resched(struct cpu_info *ci)
 {
diff --git a/sys/arch/amd64/include/cpu.h b/sys/arch/amd64/include/cpu.h
index cf322886269..9069c3df8a8 100644
--- a/sys/arch/amd64/include/cpu.h
+++ b/sys/arch/amd64/include/cpu.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: cpu.h,v 1.158 2023/07/27 00:28:24 guenther Exp $	*/
+/*	$OpenBSD: cpu.h,v 1.159 2023/08/23 01:55:46 cheloha Exp $	*/
 /*	$NetBSD: cpu.h,v 1.1 2003/04/26 18:39:39 fvdl Exp $	*/
 
 /*-
@@ -408,6 +408,8 @@ int	amd64_pa_used(paddr_t);
 extern void (*cpu_idle_cycle_fcn)(void);
 #define	cpu_idle_cycle()	(*cpu_idle_cycle_fcn)()
 #define	cpu_idle_leave()	do { /* nothing */ } while (0)
+extern void (*initclock_func)(void);
+extern void (*startclock_func)(void);
 
 struct region_descriptor;
 void	lgdt(struct region_descriptor *);
@@ -418,7 +420,6 @@ void	switch_exit(struct proc *, void (*)(struct proc *));
 void	proc_trampoline(void);
 
 /* clock.c */
-extern void (*initclock_func)(void);
 void	startclocks(void);
 void	rtcinit(void);
 void	rtcstart(void);
@@ -426,6 +427,7 @@ void	rtcstop(void);
 void	i8254_delay(int);
 void	i8254_initclocks(void);
 void	i8254_startclock(void);
+void	i8254_start_both_clocks(void);
 void	i8254_inittimecounter(void);
 void	i8254_inittimecounter_simple(void);
 
diff --git a/sys/arch/amd64/isa/clock.c b/sys/arch/amd64/isa/clock.c
index 019259ffdff..3dd79b1769d 100644
--- a/sys/arch/amd64/isa/clock.c
+++ b/sys/arch/amd64/isa/clock.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: clock.c,v 1.40 2023/07/25 18:16:19 cheloha Exp $	*/
+/*	$OpenBSD: clock.c,v 1.41 2023/08/23 01:55:46 cheloha Exp $	*/
 /*	$NetBSD: clock.c,v 1.1 2003/04/26 18:39:50 fvdl Exp $	*/
 
 /*-
@@ -284,7 +284,11 @@ i8254_initclocks(void)
 	stathz = 128;
 	profhz = 1024;		/* XXX does not divide into 1 billion */
 	clockintr_init(0);
+}
 
+void
+i8254_start_both_clocks(void)
+{
 	clockintr_cpu_init(NULL);
 
 	/*
diff --git a/sys/arch/arm/cortex/agtimer.c b/sys/arch/arm/cortex/agtimer.c
index 13b0af6f8e1..88e201abe8a 100644
--- a/sys/arch/arm/cortex/agtimer.c
+++ b/sys/arch/arm/cortex/agtimer.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: agtimer.c,v 1.18 2023/07/25 18:16:19 cheloha Exp $ */
+/* $OpenBSD: agtimer.c,v 1.19 2023/08/23 01:55:46 cheloha Exp $ */
 /*
  * Copyright (c) 2011 Dale Rahn <drahn@openbsd.org>
  * Copyright (c) 2013 Patrick Wildt <patrick@blueri.se>
@@ -227,7 +227,6 @@ void
 agtimer_cpu_initclocks(void)
 {
 	struct agtimer_softc	*sc = agtimer_cd.cd_devs[0];
-	uint32_t		 reg;
 
 	stathz = hz;
 	profhz = stathz * 10;
@@ -237,21 +236,11 @@ agtimer_cpu_initclocks(void)
 		agtimer_set_clockrate(agtimer_frequency);
 	}
 
-	clockintr_cpu_init(&agtimer_intrclock);
-
 	/* Setup secure and non-secure timer IRQs. */
 	arm_intr_establish_fdt_idx(sc->sc_node, 0, IPL_CLOCK,
 	    agtimer_intr, NULL, "tick");
 	arm_intr_establish_fdt_idx(sc->sc_node, 1, IPL_CLOCK,
 	    agtimer_intr, NULL, "tick");
-
-	reg = agtimer_get_ctrl();
-	reg &= ~GTIMER_CNTP_CTL_IMASK;
-	reg |= GTIMER_CNTP_CTL_ENABLE;
-	agtimer_set_tval(INT32_MAX);
-	agtimer_set_ctrl(reg);
-
-	clockintr_trigger();
 }
 
 void
diff --git a/sys/arch/arm/cortex/amptimer.c b/sys/arch/arm/cortex/amptimer.c
index 6fcf495791c..299f9fe8c61 100644
--- a/sys/arch/arm/cortex/amptimer.c
+++ b/sys/arch/arm/cortex/amptimer.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: amptimer.c,v 1.17 2023/07/25 18:16:19 cheloha Exp $ */
+/* $OpenBSD: amptimer.c,v 1.18 2023/08/23 01:55:46 cheloha Exp $ */
 /*
  * Copyright (c) 2011 Dale Rahn <drahn@openbsd.org>
  *
@@ -301,10 +301,6 @@ amptimer_cpu_initclocks(void)
 	/* Enable private timer counter and interrupt. */
 	bus_space_write_4(sc->sc_iot, sc->sc_pioh, PTIMER_CTRL,
 	    (PTIMER_CTRL_ENABLE | PTIMER_CTRL_IRQEN));
-
-	/* Start the clock interrupt cycle. */
-	clockintr_cpu_init(&amptimer_intrclock);
-	clockintr_trigger();
 }
 
 void
diff --git a/sys/arch/arm/include/cpu.h b/sys/arch/arm/include/cpu.h
index 986e1798cb9..1ced238694e 100644
--- a/sys/arch/arm/include/cpu.h
+++ b/sys/arch/arm/include/cpu.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: cpu.h,v 1.63 2023/07/25 18:16:19 cheloha Exp $	*/
+/*	$OpenBSD: cpu.h,v 1.64 2023/08/23 01:55:46 cheloha Exp $	*/
 /*	$NetBSD: cpu.h,v 1.34 2003/06/23 11:01:08 martin Exp $	*/
 
 /*
@@ -329,8 +329,6 @@ intr_restore(u_long cpsr)
 	__asm volatile ("msr cpsr_c, %0" :: "r"(cpsr));
 }
 
-void	cpu_startclock(void);
-
 #endif /* _KERNEL */
 
 #ifdef MULTIPROCESSOR
diff --git a/sys/arch/arm64/dev/agtimer.c b/sys/arch/arm64/dev/agtimer.c
index 32f0688148e..14fb14f0088 100644
--- a/sys/arch/arm64/dev/agtimer.c
+++ b/sys/arch/arm64/dev/agtimer.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: agtimer.c,v 1.25 2023/08/11 01:28:19 cheloha Exp $ */
+/* $OpenBSD: agtimer.c,v 1.26 2023/08/23 01:55:46 cheloha Exp $ */
 /*
  * Copyright (c) 2011 Dale Rahn <drahn@openbsd.org>
  * Copyright (c) 2013 Patrick Wildt <patrick@blueri.se>
@@ -290,8 +290,6 @@ void
 agtimer_cpu_initclocks(void)
 {
 	struct agtimer_softc	*sc = agtimer_cd.cd_devs[0];
-	uint32_t		 reg;
-	uint64_t		 kctl;
 
 	stathz = hz;
 	profhz = stathz * 10;
@@ -304,20 +302,6 @@ agtimer_cpu_initclocks(void)
 	/* configure virtual timer interrupt */
 	sc->sc_ih = arm_intr_establish_fdt_idx(sc->sc_node, 2,
 	    IPL_CLOCK|IPL_MPSAFE, agtimer_intr, NULL, "tick");
-
-	clockintr_cpu_init(&agtimer_intrclock);
-
-	reg = agtimer_get_ctrl();
-	reg &= ~GTIMER_CNTV_CTL_IMASK;
-	reg |= GTIMER_CNTV_CTL_ENABLE;
-	agtimer_set_tval(INT32_MAX);
-	agtimer_set_ctrl(reg);
-
-	clockintr_trigger();
-
-	/* enable userland access to virtual counter */
-	kctl = READ_SPECIALREG(CNTKCTL_EL1);
-	WRITE_SPECIALREG(CNTKCTL_EL1, kctl | CNTKCTL_EL0VCTEN);
 }
 
 void
@@ -343,7 +327,8 @@ agtimer_startclock(void)
 	uint64_t kctl;
 	uint32_t reg;
 
-	arm_intr_route(sc->sc_ih, 1, curcpu());
+	if (!CPU_IS_PRIMARY(curcpu()))
+		arm_intr_route(sc->sc_ih, 1, curcpu());
 
 	clockintr_cpu_init(&agtimer_intrclock);
 
diff --git a/sys/arch/arm64/include/cpu.h b/sys/arch/arm64/include/cpu.h
index ab9fdcb3758..ec514d8e4d4 100644
--- a/sys/arch/arm64/include/cpu.h
+++ b/sys/arch/arm64/include/cpu.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: cpu.h,v 1.38 2023/07/25 18:16:20 cheloha Exp $ */
+/* $OpenBSD: cpu.h,v 1.39 2023/08/23 01:55:46 cheloha Exp $ */
 /*
  * Copyright (c) 2016 Dale Rahn <drahn@dalerahn.com>
  *
@@ -344,7 +344,6 @@ intr_restore(u_long daif)
 }
 
 void	cpu_halt(void);
-void	cpu_startclock(void);
 int	cpu_suspend_primary(void);
 void	cpu_resume_secondary(struct cpu_info *);
 
diff --git a/sys/arch/armv7/omap/dmtimer.c b/sys/arch/armv7/omap/dmtimer.c
index 2d0995112c3..985428bd6d3 100644
--- a/sys/arch/armv7/omap/dmtimer.c
+++ b/sys/arch/armv7/omap/dmtimer.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: dmtimer.c,v 1.19 2023/07/25 18:16:19 cheloha Exp $	*/
+/*	$OpenBSD: dmtimer.c,v 1.20 2023/08/23 01:55:46 cheloha Exp $	*/
 /*
  * Copyright (c) 2007,2009 Dale Rahn <drahn@openbsd.org>
  * Copyright (c) 2013 Raphael Graf <r@undefined.ch>
@@ -102,6 +102,7 @@ int dmtimer_intr(void *frame);
 void dmtimer_reset_tisr(void);
 void dmtimer_wait(int reg);
 void dmtimer_cpu_initclocks(void);
+void dmtimer_cpu_startclock(void);
 void dmtimer_delay(u_int);
 void dmtimer_setstatclockrate(int newhz);
 
@@ -195,7 +196,7 @@ dmtimer_attach(struct device *parent, struct device *self, void *args)
 		dmtimer_timecounter.tc_priv = sc;
 		tc_init(&dmtimer_timecounter);
 		arm_clock_register(dmtimer_cpu_initclocks, dmtimer_delay,
-		    dmtimer_setstatclockrate, NULL);
+		    dmtimer_setstatclockrate, dmtimer_cpu_startclock);
 	}
 	else
 		panic("attaching too many dmtimers at 0x%lx",
@@ -247,7 +248,11 @@ dmtimer_cpu_initclocks(void)
 	bus_space_write_4(sc->sc_iot, sc->sc_ioh[0], DM_TLDR, 0);
 	bus_space_write_4(sc->sc_iot, sc->sc_ioh[0], DM_TIER, DM_TIER_OVF_EN);
 	bus_space_write_4(sc->sc_iot, sc->sc_ioh[0], DM_TWER, DM_TWER_OVF_EN);
+}
 
+void
+dmtimer_cpu_startclock(void)
+{
 	/* start the clock interrupt cycle */
 	clockintr_cpu_init(&dmtimer_intrclock);
 	clockintr_trigger();
diff --git a/sys/arch/armv7/omap/gptimer.c b/sys/arch/armv7/omap/gptimer.c
index 6cac9de9461..72cf3e0566a 100644
--- a/sys/arch/armv7/omap/gptimer.c
+++ b/sys/arch/armv7/omap/gptimer.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: gptimer.c,v 1.20 2023/07/25 18:16:19 cheloha Exp $ */
+/* $OpenBSD: gptimer.c,v 1.21 2023/08/23 01:55:46 cheloha Exp $ */
 /*
  * Copyright (c) 2007,2009 Dale Rahn <drahn@openbsd.org>
  *
@@ -99,6 +99,7 @@ void gptimer_attach(struct device *parent, struct device *self, void *args);
 int gptimer_intr(void *frame);
 void gptimer_wait(int reg);
 void gptimer_cpu_initclocks(void);
+void gptimer_cpu_startclock(void);
 void gptimer_delay(u_int);
 void gptimer_reset_tisr(void);
 void gptimer_setstatclockrate(int newhz);
@@ -176,7 +177,7 @@ gptimer_attach(struct device *parent, struct device *self, void *args)
 		    aa->aa_dev->mem[0].addr);
 
 	arm_clock_register(gptimer_cpu_initclocks, gptimer_delay,
-	    gptimer_setstatclockrate, NULL);
+	    gptimer_setstatclockrate, gptimer_cpu_startclock);
 }
 
 int
@@ -216,7 +217,11 @@ gptimer_cpu_initclocks(void)
 	gptimer_wait(GP_TWPS_ALL);
 	bus_space_write_4(gptimer_iot, gptimer_ioh0, GP_TWER, GP_TWER_OVF_EN);
 	gptimer_wait(GP_TWPS_ALL);
+}
 
+void
+gptimer_cpu_startclock(void)
+{
 	/* start the clock interrupt cycle */
 	clockintr_cpu_init(&gptimer_intrclock);
 	clockintr_trigger();
diff --git a/sys/arch/armv7/sunxi/sxitimer.c b/sys/arch/armv7/sunxi/sxitimer.c
index 9383282e440..81b36f9c23b 100644
--- a/sys/arch/armv7/sunxi/sxitimer.c
+++ b/sys/arch/armv7/sunxi/sxitimer.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: sxitimer.c,v 1.21 2023/07/25 18:16:19 cheloha Exp $	*/
+/*	$OpenBSD: sxitimer.c,v 1.22 2023/08/23 01:55:46 cheloha Exp $	*/
 /*
  * Copyright (c) 2007,2009 Dale Rahn <drahn@openbsd.org>
  * Copyright (c) 2013 Raphael Graf <r@undefined.ch>
@@ -77,6 +77,7 @@ void	sxitimer_attach(struct device *, struct device *, void *);
 int	sxitimer_tickintr(void *);
 int	sxitimer_statintr(void *);
 void	sxitimer_cpu_initclocks(void);
+void	sxitimer_cpu_startclock(void);
 void	sxitimer_setstatclockrate(int);
 uint64_t	sxitimer_readcnt64(void);
 uint32_t	sxitimer_readcnt32(void);
@@ -191,7 +192,7 @@ sxitimer_attach(struct device *parent, struct device *self, void *aux)
 	tc_init(&sxitimer_timecounter);
 
 	arm_clock_register(sxitimer_cpu_initclocks, sxitimer_delay,
-	    sxitimer_setstatclockrate, NULL);
+	    sxitimer_setstatclockrate, sxitimer_cpu_startclock);
 
 	printf(": %d kHz", sxitimer_freq[CNTRTIMER] / 1000);
 
@@ -229,7 +230,11 @@ sxitimer_cpu_initclocks(void)
 	bus_space_write_4(sxitimer_iot, sxitimer_ioh,
 	    TIMER_CTRL(CNTRTIMER),
 	    ctrl | TIMER_ENABLE | TIMER_RELOAD | TIMER_CONTINOUS);
+}
 
+void
+sxitimer_cpu_startclock(void)
+{
 	/* start clock interrupt cycle */
 	clockintr_cpu_init(&sxitimer_intrclock);
 	clockintr_trigger();
diff --git a/sys/arch/hppa/dev/clock.c b/sys/arch/hppa/dev/clock.c
index 8e5a10eb147..2bae218e3c8 100644
--- a/sys/arch/hppa/dev/clock.c
+++ b/sys/arch/hppa/dev/clock.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: clock.c,v 1.36 2023/07/25 18:16:20 cheloha Exp $	*/
+/*	$OpenBSD: clock.c,v 1.37 2023/08/23 01:55:46 cheloha Exp $	*/
 
 /*
  * Copyright (c) 1998-2003 Michael Shalayeff
@@ -120,8 +120,6 @@ cpu_initclocks(void)
 
 	itmr_nsec_cycle_ratio = itmr_freq * (1ULL << 32) / 1000000000;
 	itmr_nsec_max = UINT64_MAX / itmr_nsec_cycle_ratio;
-
-	cpu_startclock();
 }
 
 void
diff --git a/sys/arch/hppa/include/cpu.h b/sys/arch/hppa/include/cpu.h
index 91b7de98af8..6b21bcb0742 100644
--- a/sys/arch/hppa/include/cpu.h
+++ b/sys/arch/hppa/include/cpu.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: cpu.h,v 1.100 2023/07/25 18:16:20 cheloha Exp $	*/
+/*	$OpenBSD: cpu.h,v 1.101 2023/08/23 01:55:46 cheloha Exp $	*/
 
 /*
  * Copyright (c) 2000-2004 Michael Shalayeff
@@ -241,7 +241,6 @@ int	copy_on_fault(void);
 void	proc_trampoline(void);
 int	cpu_dumpsize(void);
 int	cpu_dump(void);
-void	cpu_startclock(void);
 
 static inline unsigned int
 cpu_rnd_messybits(void)
diff --git a/sys/arch/i386/i386/lapic.c b/sys/arch/i386/i386/lapic.c
index fae8f71cbfc..49d9dfcfe89 100644
--- a/sys/arch/i386/i386/lapic.c
+++ b/sys/arch/i386/i386/lapic.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: lapic.c,v 1.55 2023/02/09 01:41:15 cheloha Exp $	*/
+/*	$OpenBSD: lapic.c,v 1.56 2023/08/23 01:55:46 cheloha Exp $	*/
 /* $NetBSD: lapic.c,v 1.1.2.8 2000/02/23 06:10:50 sommerfeld Exp $ */
 
 /*-
@@ -327,8 +327,6 @@ lapic_initclocks(void)
 	stathz = hz;
 	profhz = stathz * 10;
 	clockintr_init(CL_RNDSTAT);
-
-	lapic_startclock();
 }
 
 extern int gettick(void);	/* XXX put in header file */
@@ -422,6 +420,7 @@ lapic_calibrate_timer(struct cpu_info *ci)
 	    lapic_per_second * (1ULL << 32) / 1000000000;
 	lapic_timer_nsec_max = UINT64_MAX / lapic_timer_nsec_cycle_ratio;
 	initclock_func = lapic_initclocks;
+	startclock_func = lapic_startclock;
 }
 
 /*
diff --git a/sys/arch/i386/i386/machdep.c b/sys/arch/i386/i386/machdep.c
index 9ce08823da5..2599def386c 100644
--- a/sys/arch/i386/i386/machdep.c
+++ b/sys/arch/i386/i386/machdep.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: machdep.c,v 1.668 2023/08/16 09:51:39 jsg Exp $	*/
+/*	$OpenBSD: machdep.c,v 1.669 2023/08/23 01:55:46 cheloha Exp $	*/
 /*	$NetBSD: machdep.c,v 1.214 1996/11/10 03:16:17 thorpej Exp $	*/
 
 /*-
@@ -233,6 +233,7 @@ void (*cpusensors_setup)(struct cpu_info *);
 
 void (*delay_func)(int) = i8254_delay;
 void (*initclock_func)(void) = i8254_initclocks;
+void (*startclock_func)(void) = i8254_start_both_clocks;
 
 /*
  * Extent maps to manage I/O and ISA memory hole space.  Allocate
@@ -3438,6 +3439,12 @@ cpu_initclocks(void)
 	(*initclock_func)();		/* lapic or i8254 */
 }
 
+void
+cpu_startclock(void)
+{
+	(*startclock_func)();
+}
+
 void
 need_resched(struct cpu_info *ci)
 {
diff --git a/sys/arch/i386/include/cpu.h b/sys/arch/i386/include/cpu.h
index 2496ba30140..297344bace9 100644
--- a/sys/arch/i386/include/cpu.h
+++ b/sys/arch/i386/include/cpu.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: cpu.h,v 1.182 2023/07/25 18:16:20 cheloha Exp $	*/
+/*	$OpenBSD: cpu.h,v 1.183 2023/08/23 01:55:46 cheloha Exp $	*/
 /*	$NetBSD: cpu.h,v 1.35 1996/05/05 19:29:26 christos Exp $	*/
 
 /*-
@@ -399,6 +399,9 @@ extern int i386_has_sse2;
 
 extern void (*update_cpuspeed)(void);
 
+extern void (*initclock_func)(void);
+extern void (*startclock_func)(void);
+
 /* machdep.c */
 void	dumpconf(void);
 void	cpu_reset(void);
@@ -416,7 +419,6 @@ void	switch_exit(struct proc *);
 void	proc_trampoline(void);
 
 /* clock.c */
-extern void (*initclock_func)(void);
 void	startclocks(void);
 void	rtcinit(void);
 void	rtcstart(void);
@@ -424,6 +426,7 @@ void	rtcstop(void);
 void	i8254_delay(int);
 void	i8254_initclocks(void);
 void	i8254_startclock(void);
+void	i8254_start_both_clocks(void);
 void	i8254_inittimecounter(void);
 void	i8254_inittimecounter_simple(void);
 
diff --git a/sys/arch/i386/isa/clock.c b/sys/arch/i386/isa/clock.c
index 563feaabf99..630be7642a2 100644
--- a/sys/arch/i386/isa/clock.c
+++ b/sys/arch/i386/isa/clock.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: clock.c,v 1.66 2023/08/22 17:13:22 cheloha Exp $	*/
+/*	$OpenBSD: clock.c,v 1.67 2023/08/23 01:55:46 cheloha Exp $	*/
 /*	$NetBSD: clock.c,v 1.39 1996/05/12 23:11:54 mycroft Exp $	*/
 
 /*-
@@ -427,7 +427,11 @@ i8254_initclocks(void)
 	stathz = 128;
 	profhz = 1024;		/* XXX does not divide into 1 billion */
 	clockintr_init(0);
+}
 
+void
+i8254_start_both_clocks(void)
+{
 	clockintr_cpu_init(NULL);
 
 	/*
diff --git a/sys/arch/luna88k/luna88k/clock.c b/sys/arch/luna88k/luna88k/clock.c
index 479bf89770d..2dd6d91cae5 100644
--- a/sys/arch/luna88k/luna88k/clock.c
+++ b/sys/arch/luna88k/luna88k/clock.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: clock.c,v 1.17 2023/07/25 18:16:20 cheloha Exp $ */
+/* $OpenBSD: clock.c,v 1.18 2023/08/23 01:55:47 cheloha Exp $ */
 /* $NetBSD: clock.c,v 1.2 2000/01/11 10:29:35 nisimura Exp $ */
 
 /*
@@ -139,7 +139,11 @@ cpu_initclocks()
 	stathz = hz;
 	profhz = stathz;
 	clockintr_init(0);
+}
 
+void
+cpu_startclock(void)
+{
 	clockintr_cpu_init(NULL);
 
 	clockinitted = 1;
diff --git a/sys/arch/macppc/macppc/clock.c b/sys/arch/macppc/macppc/clock.c
index 5edfb978eb2..93084b0573a 100644
--- a/sys/arch/macppc/macppc/clock.c
+++ b/sys/arch/macppc/macppc/clock.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: clock.c,v 1.55 2023/07/25 18:16:20 cheloha Exp $	*/
+/*	$OpenBSD: clock.c,v 1.56 2023/08/23 01:55:47 cheloha Exp $	*/
 /*	$NetBSD: clock.c,v 1.1 1996/09/30 16:34:40 ws Exp $	*/
 
 /*
@@ -147,8 +147,6 @@ decr_intr(struct clockframe *frame)
 	(void) ppc_intr_disable();
 }
 
-void cpu_startclock(void);
-
 void
 cpu_initclocks(void)
 {
@@ -204,15 +202,13 @@ cpu_initclocks(void)
 
 	evcount_attach(&clk_count, "clock", &clk_irq);
 
-	clock_initialized = 1;
-	cpu_startclock();
-
 	ppc_intr_enable(intrstate);
 }
 
 void
 cpu_startclock(void)
 {
+	clock_initialized = 1;
 	clockintr_cpu_init(&dec_intrclock);
 	clockintr_trigger();
 }
diff --git a/sys/arch/mips64/include/cpu.h b/sys/arch/mips64/include/cpu.h
index 4b9f1940a94..d647dbb1964 100644
--- a/sys/arch/mips64/include/cpu.h
+++ b/sys/arch/mips64/include/cpu.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: cpu.h,v 1.143 2023/08/05 05:46:36 guenther Exp $	*/
+/*	$OpenBSD: cpu.h,v 1.144 2023/08/23 01:55:47 cheloha Exp $	*/
 
 /*-
  * Copyright (c) 1992, 1993
@@ -260,6 +260,7 @@ void	smp_rendezvous_cpus(unsigned long, void (*)(void *), void *arg);
 
 #define CPU_BUSY_CYCLE()	do {} while (0)
 
+extern void (*md_initclock)(void);
 extern void (*md_startclock)(struct cpu_info *);
 extern void (*md_triggerclock)(void);
 void	cp0_calibrate(struct cpu_info *);
diff --git a/sys/arch/mips64/mips64/clock.c b/sys/arch/mips64/mips64/clock.c
index 6badea94862..afcf68c509b 100644
--- a/sys/arch/mips64/mips64/clock.c
+++ b/sys/arch/mips64/mips64/clock.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: clock.c,v 1.50 2023/01/18 19:12:43 cheloha Exp $ */
+/*	$OpenBSD: clock.c,v 1.51 2023/08/23 01:55:47 cheloha Exp $ */
 
 /*
  * Copyright (c) 2001-2004 Opsycon AB  (www.opsycon.se / www.opsycon.com)
@@ -70,6 +70,7 @@ const struct intrclock cp0_intrclock = {
 	.ic_trigger = cp0_trigger_int5_wrapper
 };
 
+void	cp0_initclock(void);
 uint32_t cp0_int5(uint32_t, struct trapframe *);
 void 	cp0_startclock(struct cpu_info *);
 void	cp0_trigger_int5(void);
@@ -104,6 +105,7 @@ clockattach(struct device *parent, struct device *self, void *aux)
 	/* try to avoid getting clock interrupts early */
 	cp0_set_compare(cp0_get_count() - 1);
 
+	md_initclock = cp0_initclock;
 	md_startclock = cp0_startclock;
 	md_triggerclock = cp0_trigger_int5;
 }
@@ -232,6 +234,16 @@ cp0_trigger_int5_wrapper(void *unused)
 	cp0_trigger_int5();
 }
 
+void
+cp0_initclock(void)
+{
+	KASSERT(CPU_IS_PRIMARY(curcpu()));
+
+	stathz = hz;
+	profhz = stathz * 10;
+	clockintr_init(CL_RNDSTAT);
+}
+
 /*
  * Start the clock interrupt dispatch cycle.
  */
@@ -240,11 +252,7 @@ cp0_startclock(struct cpu_info *ci)
 {
 	int s;
 
-	if (CPU_IS_PRIMARY(ci)) {
-		stathz = hz;
-		profhz = stathz * 10;
-		clockintr_init(CL_RNDSTAT);
-	} else {
+	if (!CPU_IS_PRIMARY(ci)) {
 		s = splhigh();
 		nanouptime(&ci->ci_schedstate.spc_runtime);
 		splx(s);
diff --git a/sys/arch/mips64/mips64/mips64_machdep.c b/sys/arch/mips64/mips64/mips64_machdep.c
index aaa7a04a234..a8381d40291 100644
--- a/sys/arch/mips64/mips64/mips64_machdep.c
+++ b/sys/arch/mips64/mips64/mips64_machdep.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: mips64_machdep.c,v 1.42 2023/07/25 18:16:20 cheloha Exp $ */
+/*	$OpenBSD: mips64_machdep.c,v 1.43 2023/08/23 01:55:47 cheloha Exp $ */
 
 /*
  * Copyright (c) 2009, 2010, 2012 Miodrag Vallat.
@@ -219,6 +219,7 @@ tlb_asid_wrap(struct cpu_info *ci)
  *	Mips machine independent clock routines.
  */
 
+void (*md_initclock)(void);
 void (*md_startclock)(struct cpu_info *);
 void (*md_triggerclock)(void);
 
@@ -323,11 +324,18 @@ cpu_initclocks(void)
 		tc_init(&cp0_timecounter);
 	}
 
+	if (md_initclock != NULL)
+		(*md_initclock)();
+}
+
+void
+cpu_startclock(void)
+{
 #ifdef DIAGNOSTIC
 	if (md_startclock == NULL)
 		panic("no clock");
 #endif
-	(*md_startclock)(ci);
+	(*md_startclock)(curcpu());
 }
 
 void
diff --git a/sys/arch/powerpc64/include/cpu.h b/sys/arch/powerpc64/include/cpu.h
index b02553986a9..00f742b15af 100644
--- a/sys/arch/powerpc64/include/cpu.h
+++ b/sys/arch/powerpc64/include/cpu.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: cpu.h,v 1.34 2023/08/21 01:35:43 guenther Exp $	*/
+/*	$OpenBSD: cpu.h,v 1.35 2023/08/23 01:55:47 cheloha Exp $	*/
 
 /*
  * Copyright (c) 2020 Mark Kettenis <kettenis@openbsd.org>
@@ -153,7 +153,6 @@ curcpu(void)
 void	cpu_kick(struct cpu_info *);
 void	cpu_unidle(struct cpu_info *);
 void	cpu_boot_secondary_processors(void);
-void	cpu_startclock(void);
 
 extern void (*ul_setperf)(int);
 void	mp_setperf(int);
diff --git a/sys/arch/powerpc64/powerpc64/clock.c b/sys/arch/powerpc64/powerpc64/clock.c
index e17cdacaf1e..39cab54e93c 100644
--- a/sys/arch/powerpc64/powerpc64/clock.c
+++ b/sys/arch/powerpc64/powerpc64/clock.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: clock.c,v 1.11 2023/07/25 18:16:21 cheloha Exp $	*/
+/*	$OpenBSD: clock.c,v 1.12 2023/08/23 01:55:47 cheloha Exp $	*/
 
 /*
  * Copyright (c) 2020 Mark Kettenis <kettenis@openbsd.org>
@@ -53,8 +53,6 @@ static struct timecounter tb_timecounter = {
 	.tc_user = TC_TB,
 };
 
-void	cpu_startclock(void);
-
 void
 dec_rearm(void *unused, uint64_t nsecs)
 {
@@ -99,8 +97,6 @@ cpu_initclocks(void)
 	clockintr_init(CL_RNDSTAT);
 
 	evcount_attach(&clock_count, "clock", NULL);
-
-	cpu_startclock();
 }
 
 void
diff --git a/sys/arch/riscv64/include/cpu.h b/sys/arch/riscv64/include/cpu.h
index 7bd6c2cf998..aa1ae178f7d 100644
--- a/sys/arch/riscv64/include/cpu.h
+++ b/sys/arch/riscv64/include/cpu.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: cpu.h,v 1.17 2023/08/05 05:45:52 guenther Exp $	*/
+/*	$OpenBSD: cpu.h,v 1.18 2023/08/23 01:55:47 cheloha Exp $	*/
 
 /*
  * Copyright (c) 2019 Mike Larkin <mlarkin@openbsd.org>
@@ -171,7 +171,6 @@ extern struct cpu_info *cpu_info_list;
 extern struct cpu_info *cpu_info[MAXCPUS];
 
 void	cpu_boot_secondary_processors(void);
-void	cpu_startclock(void);
 
 #endif /* !MULTIPROCESSOR */
 
diff --git a/sys/arch/riscv64/riscv64/clock.c b/sys/arch/riscv64/riscv64/clock.c
index 0648a744179..cd8c8ec6da6 100644
--- a/sys/arch/riscv64/riscv64/clock.c
+++ b/sys/arch/riscv64/riscv64/clock.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: clock.c,v 1.10 2023/07/25 18:16:21 cheloha Exp $	*/
+/*	$OpenBSD: clock.c,v 1.11 2023/08/23 01:55:47 cheloha Exp $	*/
 
 /*
  * Copyright (c) 2020 Mark Kettenis <kettenis@openbsd.org>
@@ -56,7 +56,6 @@ static struct timecounter tb_timecounter = {
 	.tc_user = TC_TB,
 };
 
-void	cpu_startclock(void);
 int	clock_intr(void *);
 
 void
@@ -100,8 +99,6 @@ cpu_initclocks(void)
 
 	evcount_attach(&clock_count, "clock", NULL);
 	evcount_percpu(&clock_count);
-
-	cpu_startclock();
 }
 
 void
diff --git a/sys/arch/sh/sh/clock.c b/sys/arch/sh/sh/clock.c
index 2e3a8b62ee3..daeedf34e66 100644
--- a/sys/arch/sh/sh/clock.c
+++ b/sys/arch/sh/sh/clock.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: clock.c,v 1.15 2023/07/25 18:16:21 cheloha Exp $	*/
+/*	$OpenBSD: clock.c,v 1.16 2023/08/23 01:55:47 cheloha Exp $	*/
 /*	$NetBSD: clock.c,v 1.32 2006/09/05 11:09:36 uwe Exp $	*/
 
 /*-
@@ -260,7 +260,11 @@ cpu_initclocks(void)
 	stathz = hz;
 	profhz = stathz;
 	clockintr_init(0);
+}
 
+void
+cpu_startclock(void)
+{
 	clockintr_cpu_init(NULL);
 
 	/*
diff --git a/sys/arch/sparc64/sparc64/clock.c b/sys/arch/sparc64/sparc64/clock.c
index 0a27a726fc1..9255d571a2e 100644
--- a/sys/arch/sparc64/sparc64/clock.c
+++ b/sys/arch/sparc64/sparc64/clock.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: clock.c,v 1.79 2023/08/07 17:11:13 miod Exp $	*/
+/*	$OpenBSD: clock.c,v 1.80 2023/08/23 01:55:47 cheloha Exp $	*/
 /*	$NetBSD: clock.c,v 1.41 2001/07/24 19:29:25 eeh Exp $ */
 
 /*
@@ -562,7 +562,11 @@ cpu_initclocks(void)
 
 	for (ci = cpus; ci != NULL; ci = ci->ci_next)
 		memcpy(&ci->ci_tickintr, &level0, sizeof(level0));
+}
 
+void
+cpu_startclock(void)
+{
 	cpu_start_clock();
 }
 
diff --git a/sys/kern/kern_clock.c b/sys/kern/kern_clock.c
index 4c2175e8cf3..22b2d6043bc 100644
--- a/sys/kern/kern_clock.c
+++ b/sys/kern/kern_clock.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: kern_clock.c,v 1.114 2023/08/22 13:46:20 jsg Exp $	*/
+/*	$OpenBSD: kern_clock.c,v 1.115 2023/08/23 01:55:45 cheloha Exp $	*/
 /*	$NetBSD: kern_clock.c,v 1.34 1996/06/09 04:51:03 briggs Exp $	*/
 
 /*-
@@ -103,6 +103,9 @@ initclocks(void)
 	profclock_period = 1000000000 / profhz;
 
 	inittimecounter();
+
+	/* Start dispatching clock interrupts on the primary CPU. */
+	cpu_startclock();
 }
 
 /*
diff --git a/sys/sys/systm.h b/sys/sys/systm.h
index 65e724575f6..9a095f7d255 100644
--- a/sys/sys/systm.h
+++ b/sys/sys/systm.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: systm.h,v 1.164 2023/08/05 20:07:56 cheloha Exp $	*/
+/*	$OpenBSD: systm.h,v 1.165 2023/08/23 01:55:45 cheloha Exp $	*/
 /*	$NetBSD: systm.h,v 1.50 1996/06/09 04:55:09 briggs Exp $	*/
 
 /*-
@@ -243,6 +243,7 @@ void	initclocks(void);
 void	inittodr(time_t);
 void	resettodr(void);
 void	cpu_initclocks(void);
+void	cpu_startclock(void);
 
 void	startprofclock(struct process *);
 void	stopprofclock(struct process *);
-- 
2.20.1