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/*
* Copyright (c) 2015 Roger Pau Monné <roger.pau@citrix.com>
* 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_stack.h"
#include "opt_ddb.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <sys/pcpu.h>
#include <sys/smp.h>
#include <sys/stack.h>
#include <sys/sbuf.h>
#include <xen/xen-os.h>
#include <xen/xen_intr.h>
#include <xen/hypervisor.h>
/*
* Xen debug device
*
* Handles the VIRQ_DEBUG interrupt and prints the backtrace of each
* vCPU on the Xen console.
*/
DPCPU_DEFINE(xen_intr_handle_t, xendebug_handler);
static struct mtx lock;
static struct sbuf *buf;
static int
xendebug_drain(void *arg, const char *str, int len)
{
HYPERVISOR_console_write(__DECONST(char *, str), len);
return (len);
}
extern void
stack_capture(struct stack *st, register_t rbp);
static int
xendebug_filter(void *arg __unused)
{
#if defined(STACK) && defined(DDB)
struct stack st;
stack_save(&st);
mtx_lock_spin(&lock);
sbuf_clear(buf);
xc_printf("Printing stack trace vCPU%u\n", XEN_VCPUID());
stack_sbuf_print_ddb(buf, &st);
sbuf_finish(buf);
mtx_unlock_spin(&lock);
#endif
return (FILTER_HANDLED);
}
static void
xendebug_identify(driver_t *driver, device_t parent)
{
KASSERT(xen_domain(),
("Trying to add Xen debug device to non-xen guest"));
if (!xen_has_percpu_evtchn())
return;
if (BUS_ADD_CHILD(parent, 0, "debug", 0) == NULL)
panic("Unable to add Xen debug device.");
}
static int
xendebug_probe(device_t dev)
{
device_set_desc(dev, "Xen debug handler");
return (BUS_PROBE_NOWILDCARD);
}
static int
xendebug_attach(device_t dev)
{
int i, error;
mtx_init(&lock, "xen-dbg", NULL, MTX_SPIN);
buf = sbuf_new(NULL, NULL, 1024, SBUF_FIXEDLEN);
if (buf == NULL)
panic("Unable to create sbuf for stack dump");
sbuf_set_drain(buf, xendebug_drain, NULL);
/* Bind an event channel to a VIRQ on each VCPU. */
CPU_FOREACH(i) {
error = xen_intr_bind_virq(dev, VIRQ_DEBUG, i, xendebug_filter,
NULL, NULL, INTR_TYPE_TTY,
DPCPU_ID_PTR(i, xendebug_handler));
if (error != 0) {
printf("Failed to bind VIRQ_DEBUG to vCPU %d: %d",
i, error);
continue;
}
xen_intr_describe(DPCPU_ID_GET(i, xendebug_handler), "d%d", i);
}
return (0);
}
static device_method_t xendebug_methods[] = {
DEVMETHOD(device_identify, xendebug_identify),
DEVMETHOD(device_probe, xendebug_probe),
DEVMETHOD(device_attach, xendebug_attach),
DEVMETHOD_END
};
static driver_t xendebug_driver = {
"debug",
xendebug_methods,
0,
};
DRIVER_MODULE(xendebug, xenpv, xendebug_driver, 0, 0);
MODULE_DEPEND(xendebug, xenpv, 1, 1, 1);
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