x86: remove MP_WATCHDOG

It does not work with ULE, which is the default scheduler for over a
decade.

Reviewed by:	emaste, kib
Differential Revision:	https://reviews.freebsd.org/D36094

11 files changed, 0 insertions, 306 deletions

diff --git a/sys/amd64/amd64/machdep.c b/sys/amd64/amd64/machdep.c
index 8174a8e850c8..05342b31d2aa 100644
--- a/sys/amd64/amd64/machdep.c
+++ b/sys/amd64/amd64/machdep.c
@@ -50,7 +50,6 @@ __FBSDID("$FreeBSD$");
 #include "opt_isa.h"
 #include "opt_kstack_pages.h"
 #include "opt_maxmem.h"
-#include "opt_mp_watchdog.h"
 #include "opt_pci.h"
 #include "opt_platform.h"
 #include "opt_sched.h"
@@ -126,7 +125,6 @@ __FBSDID("$FreeBSD$");
 #include <x86/mca.h>
 #include <machine/md_var.h>
 #include <machine/metadata.h>
-#include <machine/mp_watchdog.h>
 #include <machine/pc/bios.h>
 #include <machine/pcb.h>
 #include <machine/proc.h>
diff --git a/sys/amd64/conf/NOTES b/sys/amd64/conf/NOTES
index ba6e99c0f8eb..42cc23d076b9 100644
--- a/sys/amd64/conf/NOTES
+++ b/sys/amd64/conf/NOTES
@@ -43,11 +43,6 @@ options 	IPI_PREEMPTION
 device		atpic			# Optional legacy pic support
 device		mptable			# Optional MPSPEC mptable support
 
-#
-# Watchdog routines.
-#
-options 	MP_WATCHDOG
-
 # Debugging options.
 #
 options 	COUNT_XINVLTLB_HITS	# Counters for TLB events
diff --git a/sys/amd64/include/mp_watchdog.h b/sys/amd64/include/mp_watchdog.h
deleted file mode 100644
index e1fc0742ee1e..000000000000
--- a/sys/amd64/include/mp_watchdog.h
+++ /dev/null
@@ -1,36 +0,0 @@
-/*-
- * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
- *
- * Copyright (c) 2004 Robert N. M. Watson
- * All rights reserved.
- *
- * 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 AUTHOR 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 AUTHOR 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.
- *
- * $FreeBSD$
- */
-
-#ifndef	_MACHINE_MP_WATCHDOG_H_
-#define	_MACHINE_MP_WATCHDOG_H_
-
-void	ap_watchdog(u_int cpuid);
-
-#endif /* !_MACHINE_MP_WATCHDOG_H_ */
diff --git a/sys/conf/files.x86 b/sys/conf/files.x86
index a78570a423c9..8478afab972f 100644
--- a/sys/conf/files.x86
+++ b/sys/conf/files.x86
@@ -335,7 +335,6 @@ x86/x86/legacy.c		standard
 x86/x86/mca.c			standard
 x86/x86/x86_mem.c		optional	mem
 x86/x86/mp_x86.c		optional	smp
-x86/x86/mp_watchdog.c		optional	mp_watchdog smp
 x86/x86/nexus.c			standard
 x86/x86/pvclock.c		optional	kvm_clock | xenhvm
 x86/x86/stack_machdep.c		optional	ddb | stack
diff --git a/sys/conf/options.amd64 b/sys/conf/options.amd64
index bc809553f841..8b98aa405953 100644
--- a/sys/conf/options.amd64
+++ b/sys/conf/options.amd64
@@ -8,7 +8,6 @@ COUNT_XINVLTLB_HITS	opt_smp.h
 COUNT_IPIS		opt_smp.h
 MAXMEM
 MPTABLE_FORCE_HTT
-MP_WATCHDOG
 NKPT			opt_pmap.h
 PV_STATS		opt_pmap.h
 
diff --git a/sys/conf/options.i386 b/sys/conf/options.i386
index 37b112e1e6e9..f65592653a82 100644
--- a/sys/conf/options.i386
+++ b/sys/conf/options.i386
@@ -10,7 +10,6 @@ DISABLE_PG_G		opt_pmap.h
 DISABLE_PSE		opt_pmap.h
 MAXMEM
 MPTABLE_FORCE_HTT
-MP_WATCHDOG
 NKPT			opt_pmap.h
 PERFMON
 PMAP_SHPGPERPROC	opt_pmap.h
diff --git a/sys/i386/conf/NOTES b/sys/i386/conf/NOTES
index 42aafcecd97b..882b755db67a 100644
--- a/sys/i386/conf/NOTES
+++ b/sys/i386/conf/NOTES
@@ -60,11 +60,6 @@ device		apic			# I/O apic
 options 	MPTABLE_FORCE_HTT	# Enable HTT CPUs with the MP Table
 options 	IPI_PREEMPTION
 
-#
-# Watchdog routines.
-#
-options 	MP_WATCHDOG
-
 # Debugging options.
 #
 options 	COUNT_XINVLTLB_HITS	# Counters for TLB events
diff --git a/sys/i386/i386/machdep.c b/sys/i386/i386/machdep.c
index 5bec6196ba27..41759c07e3d3 100644
--- a/sys/i386/i386/machdep.c
+++ b/sys/i386/i386/machdep.c
@@ -54,7 +54,6 @@ __FBSDID("$FreeBSD$");
 #include "opt_isa.h"
 #include "opt_kstack_pages.h"
 #include "opt_maxmem.h"
-#include "opt_mp_watchdog.h"
 #include "opt_perfmon.h"
 #include "opt_platform.h"
 
@@ -125,7 +124,6 @@ __FBSDID("$FreeBSD$");
 #include <x86/mca.h>
 #include <machine/md_var.h>
 #include <machine/metadata.h>
-#include <machine/mp_watchdog.h>
 #include <machine/pc/bios.h>
 #include <machine/pcb.h>
 #include <machine/pcb_ext.h>
diff --git a/sys/i386/include/mp_watchdog.h b/sys/i386/include/mp_watchdog.h
deleted file mode 100644
index e1fc0742ee1e..000000000000
--- a/sys/i386/include/mp_watchdog.h
+++ /dev/null
@@ -1,36 +0,0 @@
-/*-
- * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
- *
- * Copyright (c) 2004 Robert N. M. Watson
- * All rights reserved.
- *
- * 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 AUTHOR 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 AUTHOR 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.
- *
- * $FreeBSD$
- */
-
-#ifndef	_MACHINE_MP_WATCHDOG_H_
-#define	_MACHINE_MP_WATCHDOG_H_
-
-void	ap_watchdog(u_int cpuid);
-
-#endif /* !_MACHINE_MP_WATCHDOG_H_ */
diff --git a/sys/x86/x86/cpu_machdep.c b/sys/x86/x86/cpu_machdep.c
index 759d9e8c6c95..7127ca99999e 100644
--- a/sys/x86/x86/cpu_machdep.c
+++ b/sys/x86/x86/cpu_machdep.c
@@ -50,7 +50,6 @@ __FBSDID("$FreeBSD$");
 #include "opt_kdb.h"
 #include "opt_kstack_pages.h"
 #include "opt_maxmem.h"
-#include "opt_mp_watchdog.h"
 #include "opt_platform.h"
 #include "opt_sched.h"
 #ifdef __i386__
@@ -81,7 +80,6 @@ __FBSDID("$FreeBSD$");
 #include <machine/cputypes.h>
 #include <machine/specialreg.h>
 #include <machine/md_var.h>
-#include <machine/mp_watchdog.h>
 #include <machine/tss.h>
 #ifdef SMP
 #include <machine/smp.h>
@@ -656,9 +654,6 @@ cpu_idle(int busy)
 	sbintime_t sbt = -1;
 
 	CTR1(KTR_SPARE2, "cpu_idle(%d)", busy);
-#ifdef MP_WATCHDOG
-	ap_watchdog(PCPU_GET(cpuid));
-#endif
 
 	/* If we are busy - try to use fast methods. */
 	if (busy) {
diff --git a/sys/x86/x86/mp_watchdog.c b/sys/x86/x86/mp_watchdog.c
deleted file mode 100644
index 0823f90d060e..000000000000
--- a/sys/x86/x86/mp_watchdog.c
+++ /dev/null
@@ -1,212 +0,0 @@
-/*-
- * Copyright (c) 2004 Robert N. M. Watson
- * All rights reserved.
- *
- * 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 AUTHOR 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 AUTHOR 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.
- *
- * $FreeBSD$
- */
-
-#include "opt_mp_watchdog.h"
-#include "opt_sched.h"
-
-#ifdef SCHED_ULE
-#error MP_WATCHDOG cannot currently be used with SCHED_ULE
-#endif
-
-#include <sys/param.h>
-#include <sys/kdb.h>
-#include <sys/kernel.h>
-#include <sys/lock.h>
-#include <sys/mutex.h>
-#include <sys/pcpu.h>
-#include <sys/proc.h>
-#include <sys/sysctl.h>
-#include <sys/systm.h>
-
-#include <machine/smp.h>
-#include <x86/apicreg.h>
-#include <x86/apicvar.h>
-#include <machine/mp_watchdog.h>
-
-/*
- * mp_watchdog hijacks the idle thread on a specified CPU, prevents new work
- * from being scheduled there, and uses it as a "watchdog" to detect kernel
- * failure on other CPUs.  This is made reasonable by inclusion of logical
- * processors in Xeon hardware.  The watchdog is configured by setting the
- * debug.watchdog sysctl/tunable to the CPU of interest.  A callout will then
- * begin executing reseting a timer that is gradually lowered by the watching
- * thread.  If the timer reaches 0, the watchdog fires by ether dropping
- * directly to the debugger, or by sending an NMI IPI to the boot processor.
- * This is a somewhat less efficient substitute for dedicated watchdog
- * hardware, but can be quite an effective tool for debugging hangs.
- *
- * XXXRW: This should really use the watchdog(9)/watchdog(4) framework, but
- * doesn't yet.
- */
-static int	watchdog_cpu = -1;
-static int	watchdog_dontfire = 1;
-static int	watchdog_timer = -1;
-static int	watchdog_nmi = 1;
-
-SYSCTL_INT(_debug, OID_AUTO, watchdog_nmi, CTLFLAG_RWTUN, &watchdog_nmi, 0,
-    "IPI the boot processor with an NMI to enter the debugger");
-
-static struct callout	watchdog_callout;
-
-static void watchdog_change(int wdcpu);
-
-/*
- * Number of seconds before the watchdog will fire if the callout fails to
- * reset the timer.
- */
-#define	WATCHDOG_THRESHOLD	10
-
-static void
-watchdog_init(void *arg)
-{
-
-	callout_init(&watchdog_callout, 1);
-	if (watchdog_cpu != -1)
-		watchdog_change(watchdog_cpu);
-}
-
-/*
- * This callout resets a timer until the watchdog kicks in.  It acquires some
- * critical locks to make sure things haven't gotten wedged with those locks
- * held.
- */
-static void
-watchdog_function(void *arg)
-{
-
-	/*
-	 * Since the timer ran, we must not be wedged.  Acquire some critical
-	 * locks to make sure.  Then reset the timer.
-	 */
-	mtx_lock(&Giant);
-	watchdog_timer = WATCHDOG_THRESHOLD;
-	mtx_unlock(&Giant);
-	callout_reset(&watchdog_callout, 1 * hz, watchdog_function, NULL);
-}
-SYSINIT(watchdog_init, SI_SUB_DRIVERS, SI_ORDER_ANY, watchdog_init, NULL);
-
-static void
-watchdog_change(int wdcpu)
-{
-
-	if (wdcpu == -1 || wdcpu == 0xffffffff) {
-		/*
-		 * Disable the watchdog.
-		 */
-		watchdog_cpu = -1;
-		watchdog_dontfire = 1;
-		callout_stop(&watchdog_callout);
-		printf("watchdog stopped\n");
-	} else {
-		watchdog_timer = WATCHDOG_THRESHOLD;
-		watchdog_dontfire = 0;
-		watchdog_cpu = wdcpu;
-		callout_reset(&watchdog_callout, 1 * hz, watchdog_function,
-		    NULL);
-	}
-}
-
-/*
- * This sysctl sets which CPU is the watchdog CPU.  Set to -1 or 0xffffffff
- * to disable the watchdog.
- */
-static int
-sysctl_watchdog(SYSCTL_HANDLER_ARGS)
-{
-	int error, temp;
-
-	temp = watchdog_cpu;
-	error = sysctl_handle_int(oidp, &temp, 0, req);
-	if (error)
-		return (error);
-
-	if (req->newptr != NULL)
-		watchdog_change(temp);
-	return (0);
-}
-SYSCTL_PROC(_debug, OID_AUTO, watchdog,
-    CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
-    0, 0, sysctl_watchdog, "I",
-    "");
-
-/*
- * Drop into the debugger by sending an IPI NMI to the boot processor.
- */
-static void
-watchdog_ipi_nmi(void)
-{
-
-	/*
-	 * Deliver NMI to the boot processor.  Why not?
-	 */
-	lapic_ipi_raw(APIC_DEST_DESTFLD | APIC_TRIGMOD_EDGE |
-	    APIC_LEVEL_ASSERT | APIC_DESTMODE_PHY | APIC_DELMODE_NMI,
-	    boot_cpu_id);
-	lapic_ipi_wait(-1);
-}
-
-/*
- * ap_watchdog() is called by the SMP idle loop code.  It works on the same
- * premise that the disabling of logical processors does: that if the cpu is
- * idle, then it can ignore the world from then on, as nothing will be
- * scheduled on it.  Leaving aside multi-runqueue schedulers (SCHED_ULE) and
- * explicit process migration (sched_bind()), this is not an unreasonable
- * assumption.
- */
-void
-ap_watchdog(u_int cpuid)
-{
-	char old_pcomm[MAXCOMLEN + 1];
-	struct proc *p;
-
-	if (watchdog_cpu != cpuid)
-		return;
-
-	printf("watchdog started on cpu %d\n", cpuid);
-	p = curproc;
-	bcopy(p->p_comm, old_pcomm, MAXCOMLEN + 1);
-	snprintf(p->p_comm, MAXCOMLEN + 1, "mp_watchdog cpu %d", cpuid);
-	while (1) {
-		DELAY(1000000);				/* One second. */
-		if (watchdog_cpu != cpuid)
-			break;
-		atomic_subtract_int(&watchdog_timer, 1);
-		if (watchdog_timer < 4)
-			printf("Watchdog timer: %d\n", watchdog_timer);
-		if (watchdog_timer == 0 && watchdog_dontfire == 0) {
-			printf("Watchdog firing!\n");
-			watchdog_dontfire = 1;
-			if (watchdog_nmi)
-				watchdog_ipi_nmi();
-			else
-				kdb_enter(KDB_WHY_WATCHDOG, "mp_watchdog");
-		}
-	}
-	bcopy(old_pcomm, p->p_comm, MAXCOMLEN + 1);
-	printf("watchdog stopped on cpu %d\n", cpuid);
-}