FreeBSD/Linux Kernel Cross Reference
sys/kern/subr_kdb.c
1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2004 The FreeBSD Project
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 *
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
31
32 #include "opt_kdb.h"
33 #include "opt_stack.h"
34
35 #include <sys/param.h>
36 #include <sys/systm.h>
37 #include <sys/cons.h>
38 #include <sys/kdb.h>
39 #include <sys/kernel.h>
40 #include <sys/malloc.h>
41 #include <sys/lock.h>
42 #include <sys/pcpu.h>
43 #include <sys/proc.h>
44 #include <sys/sbuf.h>
45 #include <sys/smp.h>
46 #include <sys/stack.h>
47 #include <sys/sysctl.h>
48
49 #include <machine/kdb.h>
50 #include <machine/pcb.h>
51
52 #ifdef SMP
53 #include <machine/smp.h>
54 #endif
55
56 #include <security/mac/mac_framework.h>
57
58 u_char __read_frequently kdb_active = 0;
59 static void *kdb_jmpbufp = NULL;
60 struct kdb_dbbe *kdb_dbbe = NULL;
61 static struct pcb kdb_pcb;
62 struct pcb *kdb_thrctx = NULL;
63 struct thread *kdb_thread = NULL;
64 struct trapframe *kdb_frame = NULL;
65
66 #ifdef BREAK_TO_DEBUGGER
67 #define KDB_BREAK_TO_DEBUGGER 1
68 #else
69 #define KDB_BREAK_TO_DEBUGGER 0
70 #endif
71
72 #ifdef ALT_BREAK_TO_DEBUGGER
73 #define KDB_ALT_BREAK_TO_DEBUGGER 1
74 #else
75 #define KDB_ALT_BREAK_TO_DEBUGGER 0
76 #endif
77
78 static int kdb_break_to_debugger = KDB_BREAK_TO_DEBUGGER;
79 static int kdb_alt_break_to_debugger = KDB_ALT_BREAK_TO_DEBUGGER;
80
81 KDB_BACKEND(null, NULL, NULL, NULL, NULL);
82
83 static int kdb_sysctl_available(SYSCTL_HANDLER_ARGS);
84 static int kdb_sysctl_current(SYSCTL_HANDLER_ARGS);
85 static int kdb_sysctl_enter(SYSCTL_HANDLER_ARGS);
86 static int kdb_sysctl_panic(SYSCTL_HANDLER_ARGS);
87 static int kdb_sysctl_panic_str(SYSCTL_HANDLER_ARGS);
88 static int kdb_sysctl_trap(SYSCTL_HANDLER_ARGS);
89 static int kdb_sysctl_trap_code(SYSCTL_HANDLER_ARGS);
90 static int kdb_sysctl_stack_overflow(SYSCTL_HANDLER_ARGS);
91
92 static SYSCTL_NODE(_debug, OID_AUTO, kdb, CTLFLAG_RW | CTLFLAG_MPSAFE, NULL,
93 "KDB nodes");
94
95 SYSCTL_PROC(_debug_kdb, OID_AUTO, available,
96 CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0,
97 kdb_sysctl_available, "A",
98 "list of available KDB backends");
99
100 SYSCTL_PROC(_debug_kdb, OID_AUTO, current,
101 CTLTYPE_STRING | CTLFLAG_RW | CTLFLAG_MPSAFE, NULL, 0,
102 kdb_sysctl_current, "A",
103 "currently selected KDB backend");
104
105 SYSCTL_PROC(_debug_kdb, OID_AUTO, enter,
106 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SECURE | CTLFLAG_MPSAFE, NULL, 0,
107 kdb_sysctl_enter, "I",
108 "set to enter the debugger");
109
110 SYSCTL_PROC(_debug_kdb, OID_AUTO, panic,
111 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SECURE | CTLFLAG_MPSAFE, NULL, 0,
112 kdb_sysctl_panic, "I",
113 "set to panic the kernel");
114
115 SYSCTL_PROC(_debug_kdb, OID_AUTO, panic_str,
116 CTLTYPE_STRING | CTLFLAG_RW | CTLFLAG_SECURE | CTLFLAG_MPSAFE, NULL, 0,
117 kdb_sysctl_panic_str, "A",
118 "trigger a kernel panic, using the provided string as the panic message");
119
120 SYSCTL_PROC(_debug_kdb, OID_AUTO, trap,
121 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SECURE | CTLFLAG_MPSAFE, NULL, 0,
122 kdb_sysctl_trap, "I",
123 "set to cause a page fault via data access");
124
125 SYSCTL_PROC(_debug_kdb, OID_AUTO, trap_code,
126 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SECURE | CTLFLAG_MPSAFE, NULL, 0,
127 kdb_sysctl_trap_code, "I",
128 "set to cause a page fault via code access");
129
130 SYSCTL_PROC(_debug_kdb, OID_AUTO, stack_overflow,
131 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SECURE | CTLFLAG_MPSAFE, NULL, 0,
132 kdb_sysctl_stack_overflow, "I",
133 "set to cause a stack overflow");
134
135 SYSCTL_INT(_debug_kdb, OID_AUTO, break_to_debugger,
136 CTLFLAG_RWTUN | CTLFLAG_SECURE,
137 &kdb_break_to_debugger, 0, "Enable break to debugger");
138
139 SYSCTL_INT(_debug_kdb, OID_AUTO, alt_break_to_debugger,
140 CTLFLAG_RWTUN | CTLFLAG_SECURE,
141 &kdb_alt_break_to_debugger, 0, "Enable alternative break to debugger");
142
143 /*
144 * Flag to indicate to debuggers why the debugger was entered.
145 */
146 const char * volatile kdb_why = KDB_WHY_UNSET;
147
148 static int
149 kdb_sysctl_available(SYSCTL_HANDLER_ARGS)
150 {
151 struct kdb_dbbe **iter;
152 struct sbuf sbuf;
153 int error;
154
155 sbuf_new_for_sysctl(&sbuf, NULL, 64, req);
156 SET_FOREACH(iter, kdb_dbbe_set) {
157 if ((*iter)->dbbe_active == 0)
158 sbuf_printf(&sbuf, "%s ", (*iter)->dbbe_name);
159 }
160 error = sbuf_finish(&sbuf);
161 sbuf_delete(&sbuf);
162 return (error);
163 }
164
165 static int
166 kdb_sysctl_current(SYSCTL_HANDLER_ARGS)
167 {
168 char buf[16];
169 int error;
170
171 if (kdb_dbbe != NULL)
172 strlcpy(buf, kdb_dbbe->dbbe_name, sizeof(buf));
173 else
174 *buf = '\0';
175 error = sysctl_handle_string(oidp, buf, sizeof(buf), req);
176 if (error != 0 || req->newptr == NULL)
177 return (error);
178 if (kdb_active)
179 return (EBUSY);
180 return (kdb_dbbe_select(buf));
181 }
182
183 static int
184 kdb_sysctl_enter(SYSCTL_HANDLER_ARGS)
185 {
186 int error, i;
187
188 error = sysctl_wire_old_buffer(req, sizeof(int));
189 if (error == 0) {
190 i = 0;
191 error = sysctl_handle_int(oidp, &i, 0, req);
192 }
193 if (error != 0 || req->newptr == NULL)
194 return (error);
195 if (kdb_active)
196 return (EBUSY);
197 kdb_enter(KDB_WHY_SYSCTL, "sysctl debug.kdb.enter");
198 return (0);
199 }
200
201 static int
202 kdb_sysctl_panic(SYSCTL_HANDLER_ARGS)
203 {
204 int error, i;
205
206 error = sysctl_wire_old_buffer(req, sizeof(int));
207 if (error == 0) {
208 i = 0;
209 error = sysctl_handle_int(oidp, &i, 0, req);
210 }
211 if (error != 0 || req->newptr == NULL)
212 return (error);
213 panic("kdb_sysctl_panic");
214 return (0);
215 }
216
217 static int
218 kdb_sysctl_panic_str(SYSCTL_HANDLER_ARGS)
219 {
220 int error;
221 static char buf[256]; /* static buffer to limit mallocs when panicing */
222
223 *buf = '\0';
224 error = sysctl_handle_string(oidp, buf, sizeof(buf), req);
225 if (error != 0 || req->newptr == NULL)
226 return (error);
227 panic("kdb_sysctl_panic: %s", buf);
228 return (0);
229 }
230
231 static int
232 kdb_sysctl_trap(SYSCTL_HANDLER_ARGS)
233 {
234 int error, i;
235 int *addr = (int *)0x10;
236
237 error = sysctl_wire_old_buffer(req, sizeof(int));
238 if (error == 0) {
239 i = 0;
240 error = sysctl_handle_int(oidp, &i, 0, req);
241 }
242 if (error != 0 || req->newptr == NULL)
243 return (error);
244 return (*addr);
245 }
246
247 static int
248 kdb_sysctl_trap_code(SYSCTL_HANDLER_ARGS)
249 {
250 int error, i;
251 void (*fp)(u_int, u_int, u_int) = (void *)0xdeadc0de;
252
253 error = sysctl_wire_old_buffer(req, sizeof(int));
254 if (error == 0) {
255 i = 0;
256 error = sysctl_handle_int(oidp, &i, 0, req);
257 }
258 if (error != 0 || req->newptr == NULL)
259 return (error);
260 (*fp)(0x11111111, 0x22222222, 0x33333333);
261 return (0);
262 }
263
264 static void kdb_stack_overflow(volatile int *x) __noinline;
265 static void
266 kdb_stack_overflow(volatile int *x)
267 {
268
269 if (*x > 10000000)
270 return;
271 kdb_stack_overflow(x);
272 *x += PCPU_GET(cpuid) / 1000000;
273 }
274
275 static int
276 kdb_sysctl_stack_overflow(SYSCTL_HANDLER_ARGS)
277 {
278 int error, i;
279 volatile int x;
280
281 error = sysctl_wire_old_buffer(req, sizeof(int));
282 if (error == 0) {
283 i = 0;
284 error = sysctl_handle_int(oidp, &i, 0, req);
285 }
286 if (error != 0 || req->newptr == NULL)
287 return (error);
288 x = 0;
289 kdb_stack_overflow(&x);
290 return (0);
291 }
292
293 void
294 kdb_panic(const char *msg)
295 {
296
297 kdb_why = KDB_WHY_PANIC;
298 printf("KDB: panic\n");
299 panic("%s", msg);
300 }
301
302 void
303 kdb_reboot(void)
304 {
305
306 kdb_why = KDB_WHY_REBOOT;
307 printf("KDB: reboot requested\n");
308 shutdown_nice(0);
309 }
310
311 /*
312 * Solaris implements a new BREAK which is initiated by a character sequence
313 * CR ~ ^b which is similar to a familiar pattern used on Sun servers by the
314 * Remote Console.
315 *
316 * Note that this function may be called from almost anywhere, with interrupts
317 * disabled and with unknown locks held, so it must not access data other than
318 * its arguments. Its up to the caller to ensure that the state variable is
319 * consistent.
320 */
321 #define KEY_CR 13 /* CR '\r' */
322 #define KEY_TILDE 126 /* ~ */
323 #define KEY_CRTLB 2 /* ^B */
324 #define KEY_CRTLP 16 /* ^P */
325 #define KEY_CRTLR 18 /* ^R */
326
327 /* States of th KDB "alternate break sequence" detecting state machine. */
328 enum {
329 KDB_ALT_BREAK_SEEN_NONE,
330 KDB_ALT_BREAK_SEEN_CR,
331 KDB_ALT_BREAK_SEEN_CR_TILDE,
332 };
333
334 int
335 kdb_break(void)
336 {
337
338 if (!kdb_break_to_debugger)
339 return (0);
340 kdb_enter(KDB_WHY_BREAK, "Break to debugger");
341 return (KDB_REQ_DEBUGGER);
342 }
343
344 static int
345 kdb_alt_break_state(int key, int *state)
346 {
347 int brk;
348
349 /* All states transition to KDB_ALT_BREAK_SEEN_CR on a CR. */
350 if (key == KEY_CR) {
351 *state = KDB_ALT_BREAK_SEEN_CR;
352 return (0);
353 }
354
355 brk = 0;
356 switch (*state) {
357 case KDB_ALT_BREAK_SEEN_CR:
358 *state = KDB_ALT_BREAK_SEEN_NONE;
359 if (key == KEY_TILDE)
360 *state = KDB_ALT_BREAK_SEEN_CR_TILDE;
361 break;
362 case KDB_ALT_BREAK_SEEN_CR_TILDE:
363 *state = KDB_ALT_BREAK_SEEN_NONE;
364 if (key == KEY_CRTLB)
365 brk = KDB_REQ_DEBUGGER;
366 else if (key == KEY_CRTLP)
367 brk = KDB_REQ_PANIC;
368 else if (key == KEY_CRTLR)
369 brk = KDB_REQ_REBOOT;
370 break;
371 case KDB_ALT_BREAK_SEEN_NONE:
372 default:
373 *state = KDB_ALT_BREAK_SEEN_NONE;
374 break;
375 }
376 return (brk);
377 }
378
379 static int
380 kdb_alt_break_internal(int key, int *state, int force_gdb)
381 {
382 int brk;
383
384 if (!kdb_alt_break_to_debugger)
385 return (0);
386 brk = kdb_alt_break_state(key, state);
387 switch (brk) {
388 case KDB_REQ_DEBUGGER:
389 if (force_gdb)
390 kdb_dbbe_select("gdb");
391 kdb_enter(KDB_WHY_BREAK, "Break to debugger");
392 break;
393
394 case KDB_REQ_PANIC:
395 if (force_gdb)
396 kdb_dbbe_select("gdb");
397 kdb_panic("Panic sequence on console");
398 break;
399
400 case KDB_REQ_REBOOT:
401 kdb_reboot();
402 break;
403 }
404 return (0);
405 }
406
407 int
408 kdb_alt_break(int key, int *state)
409 {
410
411 return (kdb_alt_break_internal(key, state, 0));
412 }
413
414 /*
415 * This variation on kdb_alt_break() is used only by dcons, which has its own
416 * configuration flag to force GDB use regardless of the global KDB
417 * configuration.
418 */
419 int
420 kdb_alt_break_gdb(int key, int *state)
421 {
422
423 return (kdb_alt_break_internal(key, state, 1));
424 }
425
426 /*
427 * Print a backtrace of the calling thread. The backtrace is generated by
428 * the selected debugger, provided it supports backtraces. If no debugger
429 * is selected or the current debugger does not support backtraces, this
430 * function silently returns.
431 */
432 void
433 kdb_backtrace(void)
434 {
435
436 if (kdb_dbbe != NULL && kdb_dbbe->dbbe_trace != NULL) {
437 printf("KDB: stack backtrace:\n");
438 kdb_dbbe->dbbe_trace();
439 }
440 #ifdef STACK
441 else {
442 struct stack st;
443
444 printf("KDB: stack backtrace:\n");
445 stack_save(&st);
446 stack_print_ddb(&st);
447 }
448 #endif
449 }
450
451 /*
452 * Similar to kdb_backtrace() except that it prints a backtrace of an
453 * arbitrary thread rather than the calling thread.
454 */
455 void
456 kdb_backtrace_thread(struct thread *td)
457 {
458
459 if (kdb_dbbe != NULL && kdb_dbbe->dbbe_trace_thread != NULL) {
460 printf("KDB: stack backtrace of thread %d:\n", td->td_tid);
461 kdb_dbbe->dbbe_trace_thread(td);
462 }
463 #ifdef STACK
464 else {
465 struct stack st;
466
467 printf("KDB: stack backtrace of thread %d:\n", td->td_tid);
468 if (stack_save_td(&st, td) == 0)
469 stack_print_ddb(&st);
470 }
471 #endif
472 }
473
474 /*
475 * Set/change the current backend.
476 */
477 int
478 kdb_dbbe_select(const char *name)
479 {
480 struct kdb_dbbe *be, **iter;
481
482 SET_FOREACH(iter, kdb_dbbe_set) {
483 be = *iter;
484 if (be->dbbe_active == 0 && strcmp(be->dbbe_name, name) == 0) {
485 kdb_dbbe = be;
486 return (0);
487 }
488 }
489 return (EINVAL);
490 }
491
492 /*
493 * Enter the currently selected debugger. If a message has been provided,
494 * it is printed first. If the debugger does not support the enter method,
495 * it is entered by using breakpoint(), which enters the debugger through
496 * kdb_trap(). The 'why' argument will contain a more mechanically usable
497 * string than 'msg', and is relied upon by DDB scripting to identify the
498 * reason for entering the debugger so that the right script can be run.
499 */
500 void
501 kdb_enter(const char *why, const char *msg)
502 {
503
504 if (kdb_dbbe != NULL && kdb_active == 0) {
505 kdb_why = why;
506 if (msg != NULL)
507 printf("KDB: enter: %s\n", msg);
508 breakpoint();
509 kdb_why = KDB_WHY_UNSET;
510 }
511 }
512
513 /*
514 * Initialize the kernel debugger interface.
515 */
516 void
517 kdb_init(void)
518 {
519 struct kdb_dbbe *be, **iter;
520 int cur_pri, pri;
521
522 kdb_active = 0;
523 kdb_dbbe = NULL;
524 cur_pri = -1;
525 SET_FOREACH(iter, kdb_dbbe_set) {
526 be = *iter;
527 pri = (be->dbbe_init != NULL) ? be->dbbe_init() : -1;
528 be->dbbe_active = (pri >= 0) ? 0 : -1;
529 if (pri > cur_pri) {
530 cur_pri = pri;
531 kdb_dbbe = be;
532 }
533 }
534 if (kdb_dbbe != NULL) {
535 printf("KDB: debugger backends:");
536 SET_FOREACH(iter, kdb_dbbe_set) {
537 be = *iter;
538 if (be->dbbe_active == 0)
539 printf(" %s", be->dbbe_name);
540 }
541 printf("\n");
542 printf("KDB: current backend: %s\n",
543 kdb_dbbe->dbbe_name);
544 }
545 }
546
547 /*
548 * Handle contexts.
549 */
550 void *
551 kdb_jmpbuf(jmp_buf new)
552 {
553 void *old;
554
555 old = kdb_jmpbufp;
556 kdb_jmpbufp = new;
557 return (old);
558 }
559
560 void
561 kdb_reenter(void)
562 {
563
564 if (!kdb_active || kdb_jmpbufp == NULL)
565 return;
566
567 printf("KDB: reentering\n");
568 kdb_backtrace();
569 longjmp(kdb_jmpbufp, 1);
570 /* NOTREACHED */
571 }
572
573 void
574 kdb_reenter_silent(void)
575 {
576
577 if (!kdb_active || kdb_jmpbufp == NULL)
578 return;
579
580 longjmp(kdb_jmpbufp, 1);
581 /* NOTREACHED */
582 }
583
584 /*
585 * Thread-related support functions.
586 */
587 struct pcb *
588 kdb_thr_ctx(struct thread *thr)
589 {
590 #if defined(SMP) && defined(KDB_STOPPEDPCB)
591 struct pcpu *pc;
592 #endif
593
594 if (thr == curthread)
595 return (&kdb_pcb);
596
597 #if defined(SMP) && defined(KDB_STOPPEDPCB)
598 STAILQ_FOREACH(pc, &cpuhead, pc_allcpu) {
599 if (pc->pc_curthread == thr &&
600 CPU_ISSET(pc->pc_cpuid, &stopped_cpus))
601 return (KDB_STOPPEDPCB(pc));
602 }
603 #endif
604 return (thr->td_pcb);
605 }
606
607 struct thread *
608 kdb_thr_first(void)
609 {
610 struct proc *p;
611 struct thread *thr;
612 u_int i;
613
614 /* This function may be called early. */
615 if (pidhashtbl == NULL)
616 return (&thread0);
617
618 for (i = 0; i <= pidhash; i++) {
619 LIST_FOREACH(p, &pidhashtbl[i], p_hash) {
620 thr = FIRST_THREAD_IN_PROC(p);
621 if (thr != NULL)
622 return (thr);
623 }
624 }
625 return (NULL);
626 }
627
628 struct thread *
629 kdb_thr_from_pid(pid_t pid)
630 {
631 struct proc *p;
632
633 LIST_FOREACH(p, PIDHASH(pid), p_hash) {
634 if (p->p_pid == pid)
635 return (FIRST_THREAD_IN_PROC(p));
636 }
637 return (NULL);
638 }
639
640 struct thread *
641 kdb_thr_lookup(lwpid_t tid)
642 {
643 struct thread *thr;
644
645 thr = kdb_thr_first();
646 while (thr != NULL && thr->td_tid != tid)
647 thr = kdb_thr_next(thr);
648 return (thr);
649 }
650
651 struct thread *
652 kdb_thr_next(struct thread *thr)
653 {
654 struct proc *p;
655 u_int hash;
656
657 p = thr->td_proc;
658 thr = TAILQ_NEXT(thr, td_plist);
659 if (thr != NULL)
660 return (thr);
661 if (pidhashtbl == NULL)
662 return (NULL);
663 hash = p->p_pid & pidhash;
664 for (;;) {
665 p = LIST_NEXT(p, p_hash);
666 while (p == NULL) {
667 if (++hash > pidhash)
668 return (NULL);
669 p = LIST_FIRST(&pidhashtbl[hash]);
670 }
671 thr = FIRST_THREAD_IN_PROC(p);
672 if (thr != NULL)
673 return (thr);
674 }
675 }
676
677 int
678 kdb_thr_select(struct thread *thr)
679 {
680 if (thr == NULL)
681 return (EINVAL);
682 kdb_thread = thr;
683 kdb_thrctx = kdb_thr_ctx(thr);
684 return (0);
685 }
686
687 /*
688 * Enter the debugger due to a trap.
689 */
690 int
691 kdb_trap(int type, int code, struct trapframe *tf)
692 {
693 #ifdef SMP
694 cpuset_t other_cpus;
695 #endif
696 struct kdb_dbbe *be;
697 register_t intr;
698 int handled;
699 int did_stop_cpus;
700
701 be = kdb_dbbe;
702 if (be == NULL || be->dbbe_trap == NULL)
703 return (0);
704
705 /* We reenter the debugger through kdb_reenter(). */
706 if (kdb_active)
707 return (0);
708
709 intr = intr_disable();
710
711 if (!SCHEDULER_STOPPED()) {
712 #ifdef SMP
713 other_cpus = all_cpus;
714 CPU_ANDNOT(&other_cpus, &other_cpus, &stopped_cpus);
715 CPU_CLR(PCPU_GET(cpuid), &other_cpus);
716 stop_cpus_hard(other_cpus);
717 #endif
718 curthread->td_stopsched = 1;
719 did_stop_cpus = 1;
720 } else
721 did_stop_cpus = 0;
722
723 kdb_active++;
724
725 kdb_frame = tf;
726
727 /* Let MD code do its thing first... */
728 kdb_cpu_trap(type, code);
729
730 makectx(tf, &kdb_pcb);
731 kdb_thr_select(curthread);
732
733 cngrab();
734
735 for (;;) {
736 #ifdef MAC
737 if (mac_kdb_check_backend(be) != 0) {
738 printf("MAC prevented execution of KDB backend: %s\n",
739 be->dbbe_name);
740 /* Unhandled breakpoint traps are fatal. */
741 handled = 1;
742 break;
743 }
744 #endif
745 handled = be->dbbe_trap(type, code);
746 if (be == kdb_dbbe)
747 break;
748 be = kdb_dbbe;
749 if (be == NULL || be->dbbe_trap == NULL)
750 break;
751 printf("Switching to %s back-end\n", be->dbbe_name);
752 }
753
754 cnungrab();
755
756 kdb_active--;
757
758 if (did_stop_cpus) {
759 curthread->td_stopsched = 0;
760 #ifdef SMP
761 CPU_AND(&other_cpus, &other_cpus, &stopped_cpus);
762 restart_cpus(other_cpus);
763 #endif
764 }
765
766 intr_restore(intr);
767
768 return (handled);
769 }
Cache object: 274128421027fc1a232f8ea61c3a6558
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