df62b8a25f
Handle the VIRQ_DEBUG signal and print a stack trace of each vCPU on the Xen console. This is only used for debug purposes and is triggered by the administrator of the Xen host. Sponsored by: Citrix Systems R&D MFC after: 1 week
158 lines
4.0 KiB
C
158 lines
4.0 KiB
C
/*
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* Copyright (c) 2015 Roger Pau Monné <roger.pau@citrix.com>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "opt_stack.h"
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#include "opt_ddb.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/bus.h>
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#include <sys/kernel.h>
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#include <sys/module.h>
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#include <sys/pcpu.h>
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#include <sys/smp.h>
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#include <sys/stack.h>
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#include <sys/sbuf.h>
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#include <xen/xen-os.h>
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#include <xen/xen_intr.h>
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#include <xen/hypervisor.h>
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/*
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* Xen debug device
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*
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* Handles the VIRQ_DEBUG interrupt and prints the backtrace of each
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* vCPU on the Xen console.
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*/
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DPCPU_DEFINE(xen_intr_handle_t, xendebug_handler);
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static struct mtx lock;
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static struct sbuf *buf;
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static int
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xendebug_drain(void *arg, const char *str, int len)
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{
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HYPERVISOR_console_write(__DECONST(char *, str), len);
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return (len);
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}
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extern void
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stack_capture(struct stack *st, register_t rbp);
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static int
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xendebug_filter(void *arg)
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{
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#if defined(STACK) && defined(DDB)
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struct stack st;
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struct trapframe *frame;
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frame = arg;
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stack_zero(&st);
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stack_save(&st);
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mtx_lock_spin(&lock);
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sbuf_clear(buf);
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xc_printf("Printing stack trace vCPU%d\n", PCPU_GET(vcpu_id));
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stack_sbuf_print_ddb(buf, &st);
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sbuf_finish(buf);
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mtx_unlock_spin(&lock);
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#endif
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return (FILTER_HANDLED);
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}
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static void
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xendebug_identify(driver_t *driver, device_t parent)
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{
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KASSERT(xen_domain(),
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("Trying to add Xen debug device to non-xen guest"));
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if (xen_hvm_domain() && !xen_vector_callback_enabled)
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return;
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if (BUS_ADD_CHILD(parent, 0, "debug", 0) == NULL)
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panic("Unable to add Xen debug device.");
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}
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static int
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xendebug_probe(device_t dev)
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{
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device_set_desc(dev, "Xen debug handler");
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return (BUS_PROBE_NOWILDCARD);
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}
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static int
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xendebug_attach(device_t dev)
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{
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int i, error;
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mtx_init(&lock, "xen-dbg", NULL, MTX_SPIN);
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buf = sbuf_new(NULL, NULL, 1024, SBUF_FIXEDLEN);
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if (buf == NULL)
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panic("Unable to create sbuf for stack dump");
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sbuf_set_drain(buf, xendebug_drain, NULL);
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/* Bind an event channel to a VIRQ on each VCPU. */
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CPU_FOREACH(i) {
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error = xen_intr_bind_virq(dev, VIRQ_DEBUG, i, xendebug_filter,
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NULL, NULL, INTR_TYPE_TTY,
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DPCPU_ID_PTR(i, xendebug_handler));
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if (error != 0) {
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printf("Failed to bind VIRQ_DEBUG to vCPU %d: %d",
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i, error);
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continue;
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}
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xen_intr_describe(DPCPU_ID_GET(i, xendebug_handler), "d%d", i);
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}
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return (0);
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}
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static device_method_t xendebug_methods[] = {
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DEVMETHOD(device_identify, xendebug_identify),
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DEVMETHOD(device_probe, xendebug_probe),
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DEVMETHOD(device_attach, xendebug_attach),
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DEVMETHOD_END
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};
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static driver_t xendebug_driver = {
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"debug",
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xendebug_methods,
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0,
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};
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devclass_t xendebug_devclass;
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DRIVER_MODULE(xendebug, xenpv, xendebug_driver, xendebug_devclass, 0, 0);
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MODULE_DEPEND(xendebug, xenpv, 1, 1, 1);
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