1 /*
2 * Copyright (c) 2015 Roger Pau Monné <[email protected]>
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
xendebug_drain(void * arg,const char * str,int len)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
xendebug_filter(void * arg)72 xendebug_filter(void *arg)
73 {
74 #if defined(STACK) && defined(DDB)
75 struct stack st;
76 struct trapframe *frame;
77
78 frame = arg;
79 stack_zero(&st);
80 stack_save(&st);
81
82 mtx_lock_spin(&lock);
83 sbuf_clear(buf);
84 xc_printf("Printing stack trace vCPU%d\n", PCPU_GET(vcpu_id));
85 stack_sbuf_print_ddb(buf, &st);
86 sbuf_finish(buf);
87 mtx_unlock_spin(&lock);
88 #endif
89
90 return (FILTER_HANDLED);
91 }
92
93 static void
xendebug_identify(driver_t * driver,device_t parent)94 xendebug_identify(driver_t *driver, device_t parent)
95 {
96
97 KASSERT(xen_domain(),
98 ("Trying to add Xen debug device to non-xen guest"));
99
100 if (xen_hvm_domain() && !xen_vector_callback_enabled)
101 return;
102
103 if (BUS_ADD_CHILD(parent, 0, "debug", 0) == NULL)
104 panic("Unable to add Xen debug device.");
105 }
106
107 static int
xendebug_probe(device_t dev)108 xendebug_probe(device_t dev)
109 {
110
111 device_set_desc(dev, "Xen debug handler");
112 return (BUS_PROBE_NOWILDCARD);
113 }
114
115 static int
xendebug_attach(device_t dev)116 xendebug_attach(device_t dev)
117 {
118 int i, error;
119
120 mtx_init(&lock, "xen-dbg", NULL, MTX_SPIN);
121 buf = sbuf_new(NULL, NULL, 1024, SBUF_FIXEDLEN);
122 if (buf == NULL)
123 panic("Unable to create sbuf for stack dump");
124 sbuf_set_drain(buf, xendebug_drain, NULL);
125
126 /* Bind an event channel to a VIRQ on each VCPU. */
127 CPU_FOREACH(i) {
128 error = xen_intr_bind_virq(dev, VIRQ_DEBUG, i, xendebug_filter,
129 NULL, NULL, INTR_TYPE_TTY,
130 DPCPU_ID_PTR(i, xendebug_handler));
131 if (error != 0) {
132 printf("Failed to bind VIRQ_DEBUG to vCPU %d: %d",
133 i, error);
134 continue;
135 }
136 xen_intr_describe(DPCPU_ID_GET(i, xendebug_handler), "d%d", i);
137 }
138
139 return (0);
140 }
141
142 static device_method_t xendebug_methods[] = {
143 DEVMETHOD(device_identify, xendebug_identify),
144 DEVMETHOD(device_probe, xendebug_probe),
145 DEVMETHOD(device_attach, xendebug_attach),
146
147 DEVMETHOD_END
148 };
149
150 static driver_t xendebug_driver = {
151 "debug",
152 xendebug_methods,
153 0,
154 };
155
156 devclass_t xendebug_devclass;
157
158 DRIVER_MODULE(xendebug, xenpv, xendebug_driver, xendebug_devclass, 0, 0);
159 MODULE_DEPEND(xendebug, xenpv, 1, 1, 1);
160