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 kdb_sysctl_available(SYSCTL_HANDLER_ARGS)
103 struct kdb_dbbe *be, **iter;
109 SET_FOREACH(iter, kdb_dbbe_set) {
111 if (be->dbbe_active == 0)
112 sz += strlen(be->dbbe_name) + 1;
115 avail = malloc(sz, M_TEMP, M_WAITOK);
119 SET_FOREACH(iter, kdb_dbbe_set) {
121 if (be->dbbe_active == 0) {
122 len = snprintf(p, sz, "%s ", be->dbbe_name);
127 KASSERT(sz >= 0, ("%s", __func__));
128 error = sysctl_handle_string(oidp, avail, 0, req);
134 kdb_sysctl_current(SYSCTL_HANDLER_ARGS)
139 if (kdb_dbbe != NULL) {
140 strncpy(buf, kdb_dbbe->dbbe_name, sizeof(buf));
141 buf[sizeof(buf) - 1] = '\0';
144 error = sysctl_handle_string(oidp, buf, sizeof(buf), req);
145 if (error != 0 || req->newptr == NULL)
149 return (kdb_dbbe_select(buf));
153 kdb_sysctl_enter(SYSCTL_HANDLER_ARGS)
157 error = sysctl_wire_old_buffer(req, sizeof(int));
160 error = sysctl_handle_int(oidp, &i, 0, req);
162 if (error != 0 || req->newptr == NULL)
166 kdb_enter("sysctl debug.kdb.enter");
171 kdb_sysctl_panic(SYSCTL_HANDLER_ARGS)
175 error = sysctl_wire_old_buffer(req, sizeof(int));
178 error = sysctl_handle_int(oidp, &i, 0, req);
180 if (error != 0 || req->newptr == NULL)
182 panic("kdb_sysctl_panic");
187 kdb_sysctl_trap(SYSCTL_HANDLER_ARGS)
190 int *addr = (int *)0x10;
192 error = sysctl_wire_old_buffer(req, sizeof(int));
195 error = sysctl_handle_int(oidp, &i, 0, req);
197 if (error != 0 || req->newptr == NULL)
203 kdb_sysctl_trap_code(SYSCTL_HANDLER_ARGS)
206 void (*fp)(u_int, u_int, u_int) = (void *)0xdeadc0de;
208 error = sysctl_wire_old_buffer(req, sizeof(int));
211 error = sysctl_handle_int(oidp, &i, 0, req);
213 if (error != 0 || req->newptr == NULL)
215 (*fp)(0x11111111, 0x22222222, 0x33333333);
220 * Solaris implements a new BREAK which is initiated by a character sequence
221 * CR ~ ^b which is similar to a familiar pattern used on Sun servers by the
224 * Note that this function may be called from almost anywhere, with interrupts
225 * disabled and with unknown locks held, so it must not access data other than
226 * its arguments. Its up to the caller to ensure that the state variable is
230 #define KEY_CR 13 /* CR '\r' */
231 #define KEY_TILDE 126 /* ~ */
232 #define KEY_CRTLB 2 /* ^B */
235 kdb_alt_break(int key, int *state)
245 *state = (*state == KEY_TILDE) ? KEY_CRTLB : 0;
248 if (*state == KEY_CRTLB)
259 * Print a backtrace of the calling thread. The backtrace is generated by
260 * the selected debugger, provided it supports backtraces. If no debugger
261 * is selected or the current debugger does not support backtraces, this
262 * function silently returns.
269 if (kdb_dbbe != NULL && kdb_dbbe->dbbe_trace != NULL) {
270 printf("KDB: stack backtrace:\n");
271 kdb_dbbe->dbbe_trace();
276 * Set/change the current backend.
280 kdb_dbbe_select(const char *name)
282 struct kdb_dbbe *be, **iter;
284 SET_FOREACH(iter, kdb_dbbe_set) {
286 if (be->dbbe_active == 0 && strcmp(be->dbbe_name, name) == 0) {
295 * Enter the currently selected debugger. If a message has been provided,
296 * it is printed first. If the debugger does not support the enter method,
297 * it is entered by using breakpoint(), which enters the debugger through
302 kdb_enter(const char *msg)
305 if (kdb_dbbe != NULL && kdb_active == 0) {
307 printf("KDB: enter: %s\n", msg);
313 * Initialize the kernel debugger interface.
319 struct kdb_dbbe *be, **iter;
325 SET_FOREACH(iter, kdb_dbbe_set) {
327 pri = (be->dbbe_init != NULL) ? be->dbbe_init() : -1;
328 be->dbbe_active = (pri >= 0) ? 0 : -1;
334 if (kdb_dbbe != NULL) {
335 printf("KDB: debugger backends:");
336 SET_FOREACH(iter, kdb_dbbe_set) {
338 if (be->dbbe_active == 0)
339 printf(" %s", be->dbbe_name);
342 printf("KDB: current backend: %s\n",
343 kdb_dbbe->dbbe_name);
352 kdb_jmpbuf(jmp_buf new)
365 if (!kdb_active || kdb_jmpbufp == NULL)
368 longjmp(kdb_jmpbufp, 1);
373 * Thread related support functions.
377 kdb_thr_ctx(struct thread *thr)
379 #if defined(SMP) && defined(KDB_STOPPEDPCB)
383 if (thr == curthread)
386 #if defined(SMP) && defined(KDB_STOPPEDPCB)
387 SLIST_FOREACH(pc, &cpuhead, pc_allcpu) {
388 if (pc->pc_curthread == thr && (stopped_cpus & pc->pc_cpumask))
389 return (KDB_STOPPEDPCB(pc));
392 return (thr->td_pcb);
401 p = LIST_FIRST(&allproc);
403 if (p->p_sflag & PS_INMEM) {
404 thr = FIRST_THREAD_IN_PROC(p);
408 p = LIST_NEXT(p, p_list);
414 kdb_thr_from_pid(pid_t pid)
418 p = LIST_FIRST(&allproc);
420 if (p->p_sflag & PS_INMEM && p->p_pid == pid)
421 return (FIRST_THREAD_IN_PROC(p));
422 p = LIST_NEXT(p, p_list);
428 kdb_thr_lookup(lwpid_t tid)
432 thr = kdb_thr_first();
433 while (thr != NULL && thr->td_tid != tid)
434 thr = kdb_thr_next(thr);
439 kdb_thr_next(struct thread *thr)
444 thr = TAILQ_NEXT(thr, td_plist);
448 p = LIST_NEXT(p, p_list);
449 if (p != NULL && (p->p_sflag & PS_INMEM))
450 thr = FIRST_THREAD_IN_PROC(p);
456 kdb_thr_select(struct thread *thr)
461 kdb_thrctx = kdb_thr_ctx(thr);
466 * Enter the debugger due to a trap.
470 kdb_trap(int type, int code, struct trapframe *tf)
478 if (kdb_dbbe == NULL || kdb_dbbe->dbbe_trap == NULL)
481 /* We reenter the debugger through kdb_reenter(). */
485 intr = intr_disable();
488 if ((did_stop_cpus = kdb_stop_cpus) != 0)
489 stop_cpus(PCPU_GET(other_cpus));
496 /* Let MD code do its thing first... */
497 kdb_cpu_trap(type, code);
499 makectx(tf, &kdb_pcb);
500 kdb_thr_select(curthread);
502 handled = kdb_dbbe->dbbe_trap(type, code);
508 restart_cpus(stopped_cpus);