1 /* 2 * Copyright (c) 2015 Roger Pau Monné <roger.pau@citrix.com> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 */ 26 27 #include <sys/cdefs.h> 28 __FBSDID("$FreeBSD$"); 29 30 #include "opt_stack.h" 31 #include "opt_ddb.h" 32 33 #include <sys/param.h> 34 #include <sys/systm.h> 35 #include <sys/bus.h> 36 #include <sys/kernel.h> 37 #include <sys/lock.h> 38 #include <sys/module.h> 39 #include <sys/mutex.h> 40 #include <sys/pcpu.h> 41 #include <sys/smp.h> 42 #include <sys/stack.h> 43 #include <sys/sbuf.h> 44 45 #include <xen/xen-os.h> 46 #include <xen/xen_intr.h> 47 #include <xen/hypervisor.h> 48 49 /* 50 * Xen debug device 51 * 52 * Handles the VIRQ_DEBUG interrupt and prints the backtrace of each 53 * vCPU on the Xen console. 54 */ 55 56 DPCPU_DEFINE(xen_intr_handle_t, xendebug_handler); 57 static struct mtx lock; 58 static struct sbuf *buf; 59 60 static int 61 xendebug_drain(void *arg, const char *str, int len) 62 { 63 64 HYPERVISOR_console_write(__DECONST(char *, str), len); 65 return (len); 66 } 67 68 extern void 69 stack_capture(struct stack *st, register_t rbp); 70 71 static int 72 xendebug_filter(void *arg __unused) 73 { 74 #if defined(STACK) && defined(DDB) 75 struct stack st; 76 77 stack_zero(&st); 78 stack_save(&st); 79 80 mtx_lock_spin(&lock); 81 sbuf_clear(buf); 82 xc_printf("Printing stack trace vCPU%d\n", PCPU_GET(vcpu_id)); 83 stack_sbuf_print_ddb(buf, &st); 84 sbuf_finish(buf); 85 mtx_unlock_spin(&lock); 86 #endif 87 88 return (FILTER_HANDLED); 89 } 90 91 static void 92 xendebug_identify(driver_t *driver, device_t parent) 93 { 94 95 KASSERT(xen_domain(), 96 ("Trying to add Xen debug device to non-xen guest")); 97 98 if (!xen_has_percpu_evtchn()) 99 return; 100 101 if (BUS_ADD_CHILD(parent, 0, "debug", 0) == NULL) 102 panic("Unable to add Xen debug device."); 103 } 104 105 static int 106 xendebug_probe(device_t dev) 107 { 108 109 device_set_desc(dev, "Xen debug handler"); 110 return (BUS_PROBE_NOWILDCARD); 111 } 112 113 static int 114 xendebug_attach(device_t dev) 115 { 116 int i, error; 117 118 mtx_init(&lock, "xen-dbg", NULL, MTX_SPIN); 119 buf = sbuf_new(NULL, NULL, 1024, SBUF_FIXEDLEN); 120 if (buf == NULL) 121 panic("Unable to create sbuf for stack dump"); 122 sbuf_set_drain(buf, xendebug_drain, NULL); 123 124 /* Bind an event channel to a VIRQ on each VCPU. */ 125 CPU_FOREACH(i) { 126 error = xen_intr_bind_virq(dev, VIRQ_DEBUG, i, xendebug_filter, 127 NULL, NULL, INTR_TYPE_TTY, 128 DPCPU_ID_PTR(i, xendebug_handler)); 129 if (error != 0) { 130 printf("Failed to bind VIRQ_DEBUG to vCPU %d: %d", 131 i, error); 132 continue; 133 } 134 xen_intr_describe(DPCPU_ID_GET(i, xendebug_handler), "d%d", i); 135 } 136 137 return (0); 138 } 139 140 static device_method_t xendebug_methods[] = { 141 DEVMETHOD(device_identify, xendebug_identify), 142 DEVMETHOD(device_probe, xendebug_probe), 143 DEVMETHOD(device_attach, xendebug_attach), 144 145 DEVMETHOD_END 146 }; 147 148 static driver_t xendebug_driver = { 149 "debug", 150 xendebug_methods, 151 0, 152 }; 153 154 devclass_t xendebug_devclass; 155 156 DRIVER_MODULE(xendebug, xenpv, xendebug_driver, xendebug_devclass, 0, 0); 157 MODULE_DEPEND(xendebug, xenpv, 1, 1, 1); 158