Author: kib
Date: Wed Aug 10 13:38:44 2016
New Revision: 303912
URL: https://svnweb.freebsd.org/changeset/base/303912
Log:
MFC r303712:
Merge i386 and amd64 variants of mp_watchdog.c into x86/.
Approved by: re (gjb)
Added:
stable/11/sys/x86/x86/mp_watchdog.c
- copied unchanged from r303712, head/sys/x86/x86/mp_watchdog.c
Deleted:
stable/11/sys/amd64/amd64/mp_watchdog.c
stable/11/sys/i386/i386/mp_watchdog.c
Modified:
stable/11/sys/conf/files.amd64
stable/11/sys/conf/files.i386
stable/11/sys/conf/files.pc98
Directory Properties:
stable/11/ (props changed)
Modified: stable/11/sys/conf/files.amd64
==============================================================================
--- stable/11/sys/conf/files.amd64 Wed Aug 10 13:32:27 2016
(r303911)
+++ stable/11/sys/conf/files.amd64 Wed Aug 10 13:38:44 2016
(r303912)
@@ -123,7 +123,6 @@ amd64/amd64/machdep.c standard
amd64/amd64/mem.c optional mem
amd64/amd64/minidump_machdep.c standard
amd64/amd64/mp_machdep.c optional smp
-amd64/amd64/mp_watchdog.c optional mp_watchdog smp
amd64/amd64/mpboot.S optional smp
amd64/amd64/pmap.c standard
amd64/amd64/prof_machdep.c optional profiling-routine
@@ -619,6 +618,7 @@ x86/x86/mca.c standard
x86/x86/mptable.c optional mptable
x86/x86/mptable_pci.c optional mptable pci
x86/x86/mp_x86.c optional smp
+x86/x86/mp_watchdog.c optional mp_watchdog smp
x86/x86/msi.c optional pci
x86/x86/nexus.c standard
x86/x86/pvclock.c standard
Modified: stable/11/sys/conf/files.i386
==============================================================================
--- stable/11/sys/conf/files.i386 Wed Aug 10 13:32:27 2016
(r303911)
+++ stable/11/sys/conf/files.i386 Wed Aug 10 13:38:44 2016
(r303912)
@@ -479,7 +479,6 @@ i386/i386/mem.c optional mem
i386/i386/minidump_machdep.c standard
i386/i386/mp_clock.c optional smp
i386/i386/mp_machdep.c optional smp
-i386/i386/mp_watchdog.c optional mp_watchdog smp
i386/i386/mpboot.s optional smp
i386/i386/perfmon.c optional perfmon
i386/i386/pmap.c standard
@@ -610,6 +609,7 @@ x86/x86/mca.c standard
x86/x86/mptable.c optional apic
x86/x86/mptable_pci.c optional apic pci
x86/x86/mp_x86.c optional smp
+x86/x86/mp_watchdog.c optional mp_watchdog smp
x86/x86/msi.c optional apic pci
x86/x86/nexus.c standard
x86/x86/stack_machdep.c optional ddb | stack
Modified: stable/11/sys/conf/files.pc98
==============================================================================
--- stable/11/sys/conf/files.pc98 Wed Aug 10 13:32:27 2016
(r303911)
+++ stable/11/sys/conf/files.pc98 Wed Aug 10 13:38:44 2016
(r303912)
@@ -168,7 +168,6 @@ i386/i386/mem.c optional mem
i386/i386/minidump_machdep.c standard
i386/i386/mp_clock.c optional smp
i386/i386/mp_machdep.c optional smp
-i386/i386/mp_watchdog.c optional mp_watchdog smp
i386/i386/mpboot.s optional smp
i386/i386/perfmon.c optional perfmon
i386/i386/pmap.c standard
@@ -269,9 +268,10 @@ x86/x86/io_apic.c optional apic
x86/x86/legacy.c standard
x86/x86/local_apic.c optional apic
x86/x86/mca.c standard
-x86/x86/mp_x86.c optional smp
x86/x86/mptable.c optional apic
x86/x86/mptable_pci.c optional apic pci
+x86/x86/mp_x86.c optional smp
+x86/x86/mp_watchdog.c optional mp_watchdog smp
x86/x86/msi.c optional apic pci
x86/x86/nexus.c standard
x86/x86/stack_machdep.c optional ddb | stack
Copied: stable/11/sys/x86/x86/mp_watchdog.c (from r303712,
head/sys/x86/x86/mp_watchdog.c)
==============================================================================
--- /dev/null 00:00:00 1970 (empty, because file is newly added)
+++ stable/11/sys/x86/x86/mp_watchdog.c Wed Aug 10 13:38:44 2016
(r303912, copy of r303712, head/sys/x86/x86/mp_watchdog.c)
@@ -0,0 +1,210 @@
+/*-
+ * 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, 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);
+}
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