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 #include "opt_stack.h" 29 #include "opt_ddb.h" 30 31 #include <sys/param.h> 32 #include <sys/systm.h> 33 #include <sys/bus.h> 34 #include <sys/kernel.h> 35 #include <sys/lock.h> 36 #include <sys/module.h> 37 #include <sys/mutex.h> 38 #include <sys/pcpu.h> 39 #include <sys/smp.h> 40 #include <sys/stack.h> 41 #include <sys/sbuf.h> 42 43 #include <xen/xen-os.h> 44 #include <xen/xen_intr.h> 45 #include <xen/hypervisor.h> 46 47 /* 48 * Xen debug device 49 * 50 * Handles the VIRQ_DEBUG interrupt and prints the backtrace of each 51 * vCPU on the Xen console. 52 */ 53 54 DPCPU_DEFINE(xen_intr_handle_t, xendebug_handler); 55 static struct mtx lock; 56 static struct sbuf *buf; 57 58 static int 59 xendebug_drain(void *arg, const char *str, int len) 60 { 61 62 HYPERVISOR_console_write(__DECONST(char *, str), len); 63 return (len); 64 } 65 66 extern void 67 stack_capture(struct stack *st, register_t rbp); 68 69 static int 70 xendebug_filter(void *arg __unused) 71 { 72 #if defined(STACK) && defined(DDB) 73 struct stack st; 74 75 stack_save(&st); 76 77 mtx_lock_spin(&lock); 78 sbuf_clear(buf); 79 xc_printf("Printing stack trace vCPU%u\n", XEN_VCPUID()); 80 stack_sbuf_print_ddb(buf, &st); 81 sbuf_finish(buf); 82 mtx_unlock_spin(&lock); 83 #endif 84 85 return (FILTER_HANDLED); 86 } 87 88 static void 89 xendebug_identify(driver_t *driver, device_t parent) 90 { 91 92 KASSERT(xen_domain(), 93 ("Trying to add Xen debug device to non-xen guest")); 94 95 if (!xen_has_percpu_evtchn()) 96 return; 97 98 if (BUS_ADD_CHILD(parent, 0, "debug", 0) == NULL) 99 panic("Unable to add Xen debug device."); 100 } 101 102 static int 103 xendebug_probe(device_t dev) 104 { 105 106 device_set_desc(dev, "Xen debug handler"); 107 return (BUS_PROBE_NOWILDCARD); 108 } 109 110 static int 111 xendebug_attach(device_t dev) 112 { 113 int i, error; 114 115 mtx_init(&lock, "xen-dbg", NULL, MTX_SPIN); 116 buf = sbuf_new(NULL, NULL, 1024, SBUF_FIXEDLEN); 117 if (buf == NULL) 118 panic("Unable to create sbuf for stack dump"); 119 sbuf_set_drain(buf, xendebug_drain, NULL); 120 121 /* Bind an event channel to a VIRQ on each VCPU. */ 122 CPU_FOREACH(i) { 123 error = xen_intr_bind_virq(dev, VIRQ_DEBUG, i, xendebug_filter, 124 NULL, NULL, INTR_TYPE_TTY, 125 DPCPU_ID_PTR(i, xendebug_handler)); 126 if (error != 0) { 127 printf("Failed to bind VIRQ_DEBUG to vCPU %d: %d", 128 i, error); 129 continue; 130 } 131 xen_intr_describe(DPCPU_ID_GET(i, xendebug_handler), "d%d", i); 132 } 133 134 return (0); 135 } 136 137 static device_method_t xendebug_methods[] = { 138 DEVMETHOD(device_identify, xendebug_identify), 139 DEVMETHOD(device_probe, xendebug_probe), 140 DEVMETHOD(device_attach, xendebug_attach), 141 142 DEVMETHOD_END 143 }; 144 145 static driver_t xendebug_driver = { 146 "debug", 147 xendebug_methods, 148 0, 149 }; 150 151 DRIVER_MODULE(xendebug, xenpv, xendebug_driver, 0, 0); 152 MODULE_DEPEND(xendebug, xenpv, 1, 1, 1); 153