2 * Copyright (c) 2004 The FreeBSD Project
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
32 #include <sys/param.h>
33 #include <sys/systm.h>
35 #include <sys/kernel.h>
36 #include <sys/malloc.h>
40 #include <sys/sysctl.h>
42 #include <machine/kdb.h>
43 #include <machine/pcb.h>
46 #include <machine/smp.h>
50 void *kdb_jmpbufp = NULL;
51 struct kdb_dbbe *kdb_dbbe = NULL;
53 struct pcb *kdb_thrctx = NULL;
54 struct thread *kdb_thread = NULL;
55 struct trapframe *kdb_frame = NULL;
57 KDB_BACKEND(null, NULL, NULL, NULL);
58 SET_DECLARE(kdb_dbbe_set, struct kdb_dbbe);
60 static int kdb_sysctl_available(SYSCTL_HANDLER_ARGS);
61 static int kdb_sysctl_current(SYSCTL_HANDLER_ARGS);
62 static int kdb_sysctl_enter(SYSCTL_HANDLER_ARGS);
63 static int kdb_sysctl_panic(SYSCTL_HANDLER_ARGS);
64 static int kdb_sysctl_trap(SYSCTL_HANDLER_ARGS);
65 static int kdb_sysctl_trap_code(SYSCTL_HANDLER_ARGS);
67 SYSCTL_NODE(_debug, OID_AUTO, kdb, CTLFLAG_RW, NULL, "KDB nodes");
69 SYSCTL_PROC(_debug_kdb, OID_AUTO, available, CTLTYPE_STRING | CTLFLAG_RD, 0, 0,
70 kdb_sysctl_available, "A", "list of available KDB backends");
72 SYSCTL_PROC(_debug_kdb, OID_AUTO, current, CTLTYPE_STRING | CTLFLAG_RW, 0, 0,
73 kdb_sysctl_current, "A", "currently selected KDB backend");
75 SYSCTL_PROC(_debug_kdb, OID_AUTO, enter, CTLTYPE_INT | CTLFLAG_RW, 0, 0,
76 kdb_sysctl_enter, "I", "set to enter the debugger");
78 SYSCTL_PROC(_debug_kdb, OID_AUTO, panic, CTLTYPE_INT | CTLFLAG_RW, 0, 0,
79 kdb_sysctl_panic, "I", "set to panic the kernel");
81 SYSCTL_PROC(_debug_kdb, OID_AUTO, trap, CTLTYPE_INT | CTLFLAG_RW, 0, 0,
82 kdb_sysctl_trap, "I", "set to cause a page fault via data access");
84 SYSCTL_PROC(_debug_kdb, OID_AUTO, trap_code, CTLTYPE_INT | CTLFLAG_RW, 0, 0,
85 kdb_sysctl_trap_code, "I", "set to cause a page fault via code access");
88 * Flag indicating whether or not to IPI the other CPUs to stop them on
89 * entering the debugger. Sometimes, this will result in a deadlock as
90 * stop_cpus() waits for the other cpus to stop, so we allow it to be
94 static int kdb_stop_cpus = 1;
95 SYSCTL_INT(_debug_kdb, OID_AUTO, stop_cpus, CTLTYPE_INT | CTLFLAG_RW,
96 &kdb_stop_cpus, 0, "stop other CPUs when entering the debugger");
97 TUNABLE_INT("debug.kdb.stop_cpus", &kdb_stop_cpus);
101 * Flag to indicate to debuggers why the debugger was entered.
103 const char * volatile kdb_why = KDB_WHY_UNSET;
106 kdb_sysctl_available(SYSCTL_HANDLER_ARGS)
108 struct kdb_dbbe *be, **iter;
114 SET_FOREACH(iter, kdb_dbbe_set) {
116 if (be->dbbe_active == 0)
117 sz += strlen(be->dbbe_name) + 1;
120 avail = malloc(sz, M_TEMP, M_WAITOK);
124 SET_FOREACH(iter, kdb_dbbe_set) {
126 if (be->dbbe_active == 0) {
127 len = snprintf(p, sz, "%s ", be->dbbe_name);
132 KASSERT(sz >= 0, ("%s", __func__));
133 error = sysctl_handle_string(oidp, avail, 0, req);
139 kdb_sysctl_current(SYSCTL_HANDLER_ARGS)
144 if (kdb_dbbe != NULL) {
145 strncpy(buf, kdb_dbbe->dbbe_name, sizeof(buf));
146 buf[sizeof(buf) - 1] = '\0';
149 error = sysctl_handle_string(oidp, buf, sizeof(buf), req);
150 if (error != 0 || req->newptr == NULL)
154 return (kdb_dbbe_select(buf));
158 kdb_sysctl_enter(SYSCTL_HANDLER_ARGS)
162 error = sysctl_wire_old_buffer(req, sizeof(int));
165 error = sysctl_handle_int(oidp, &i, 0, req);
167 if (error != 0 || req->newptr == NULL)
171 kdb_enter_why(KDB_WHY_SYSCTL, "sysctl debug.kdb.enter");
176 kdb_sysctl_panic(SYSCTL_HANDLER_ARGS)
180 error = sysctl_wire_old_buffer(req, sizeof(int));
183 error = sysctl_handle_int(oidp, &i, 0, req);
185 if (error != 0 || req->newptr == NULL)
187 panic("kdb_sysctl_panic");
192 kdb_sysctl_trap(SYSCTL_HANDLER_ARGS)
195 int *addr = (int *)0x10;
197 error = sysctl_wire_old_buffer(req, sizeof(int));
200 error = sysctl_handle_int(oidp, &i, 0, req);
202 if (error != 0 || req->newptr == NULL)
208 kdb_sysctl_trap_code(SYSCTL_HANDLER_ARGS)
211 void (*fp)(u_int, u_int, u_int) = (void *)0xdeadc0de;
213 error = sysctl_wire_old_buffer(req, sizeof(int));
216 error = sysctl_handle_int(oidp, &i, 0, req);
218 if (error != 0 || req->newptr == NULL)
220 (*fp)(0x11111111, 0x22222222, 0x33333333);
225 * Solaris implements a new BREAK which is initiated by a character sequence
226 * CR ~ ^b which is similar to a familiar pattern used on Sun servers by the
229 * Note that this function may be called from almost anywhere, with interrupts
230 * disabled and with unknown locks held, so it must not access data other than
231 * its arguments. Its up to the caller to ensure that the state variable is
235 #define KEY_CR 13 /* CR '\r' */
236 #define KEY_TILDE 126 /* ~ */
237 #define KEY_CRTLB 2 /* ^B */
240 kdb_alt_break(int key, int *state)
250 *state = (*state == KEY_TILDE) ? KEY_CRTLB : 0;
253 if (*state == KEY_CRTLB)
264 * Print a backtrace of the calling thread. The backtrace is generated by
265 * the selected debugger, provided it supports backtraces. If no debugger
266 * is selected or the current debugger does not support backtraces, this
267 * function silently returns.
274 if (kdb_dbbe != NULL && kdb_dbbe->dbbe_trace != NULL) {
275 printf("KDB: stack backtrace:\n");
276 kdb_dbbe->dbbe_trace();
281 * Set/change the current backend.
285 kdb_dbbe_select(const char *name)
287 struct kdb_dbbe *be, **iter;
289 SET_FOREACH(iter, kdb_dbbe_set) {
291 if (be->dbbe_active == 0 && strcmp(be->dbbe_name, name) == 0) {
300 * Enter the currently selected debugger. If a message has been provided,
301 * it is printed first. If the debugger does not support the enter method,
302 * it is entered by using breakpoint(), which enters the debugger through
303 * kdb_trap(). The 'why' argument will contain a more mechanically usable
304 * string than 'msg', and is relied upon by DDB scripting to identify the
305 * reason for entering the debugger so that the right script can be run.
308 kdb_enter_why(const char *why, const char *msg)
311 if (kdb_dbbe != NULL && kdb_active == 0) {
313 printf("KDB: enter: %s\n", msg);
316 kdb_why = KDB_WHY_UNSET;
321 * This compatibility function exists so that kernel modules with existing
322 * dependencies will still link and function. In FreeBSD 8.0, kdb_enter() is
323 * kdb_enter_why(). In 7.x, this limits how KDB can use the entry call, and
324 * means that there won't be specific scripts for event that use the legacy
328 kdb_enter(const char *msg)
331 kdb_enter_why(KDB_WHY_UNSET, msg);
335 * Initialize the kernel debugger interface.
341 struct kdb_dbbe *be, **iter;
347 SET_FOREACH(iter, kdb_dbbe_set) {
349 pri = (be->dbbe_init != NULL) ? be->dbbe_init() : -1;
350 be->dbbe_active = (pri >= 0) ? 0 : -1;
356 if (kdb_dbbe != NULL) {
357 printf("KDB: debugger backends:");
358 SET_FOREACH(iter, kdb_dbbe_set) {
360 if (be->dbbe_active == 0)
361 printf(" %s", be->dbbe_name);
364 printf("KDB: current backend: %s\n",
365 kdb_dbbe->dbbe_name);
374 kdb_jmpbuf(jmp_buf new)
387 if (!kdb_active || kdb_jmpbufp == NULL)
390 longjmp(kdb_jmpbufp, 1);
395 * Thread related support functions.
399 kdb_thr_ctx(struct thread *thr)
401 #if defined(SMP) && defined(KDB_STOPPEDPCB)
405 if (thr == curthread)
408 #if defined(SMP) && defined(KDB_STOPPEDPCB)
409 SLIST_FOREACH(pc, &cpuhead, pc_allcpu) {
410 if (pc->pc_curthread == thr && (stopped_cpus & pc->pc_cpumask))
411 return (KDB_STOPPEDPCB(pc));
414 return (thr->td_pcb);
423 p = LIST_FIRST(&allproc);
425 if (p->p_flag & P_INMEM) {
426 thr = FIRST_THREAD_IN_PROC(p);
430 p = LIST_NEXT(p, p_list);
436 kdb_thr_from_pid(pid_t pid)
440 p = LIST_FIRST(&allproc);
442 if (p->p_flag & P_INMEM && p->p_pid == pid)
443 return (FIRST_THREAD_IN_PROC(p));
444 p = LIST_NEXT(p, p_list);
450 kdb_thr_lookup(lwpid_t tid)
454 thr = kdb_thr_first();
455 while (thr != NULL && thr->td_tid != tid)
456 thr = kdb_thr_next(thr);
461 kdb_thr_next(struct thread *thr)
466 thr = TAILQ_NEXT(thr, td_plist);
470 p = LIST_NEXT(p, p_list);
471 if (p != NULL && (p->p_flag & P_INMEM))
472 thr = FIRST_THREAD_IN_PROC(p);
478 kdb_thr_select(struct thread *thr)
483 kdb_thrctx = kdb_thr_ctx(thr);
488 * Enter the debugger due to a trap.
492 kdb_trap(int type, int code, struct trapframe *tf)
500 if (kdb_dbbe == NULL || kdb_dbbe->dbbe_trap == NULL)
503 /* We reenter the debugger through kdb_reenter(). */
507 intr = intr_disable();
510 if ((did_stop_cpus = kdb_stop_cpus) != 0)
511 stop_cpus(PCPU_GET(other_cpus));
518 /* Let MD code do its thing first... */
519 kdb_cpu_trap(type, code);
521 makectx(tf, &kdb_pcb);
522 kdb_thr_select(curthread);
524 handled = kdb_dbbe->dbbe_trap(type, code);
530 restart_cpus(stopped_cpus);