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("$FreeBSD$");
31 #include "opt_stack.h"
33 #include <sys/param.h>
34 #include <sys/systm.h>
36 #include <sys/kernel.h>
37 #include <sys/malloc.h>
42 #include <sys/stack.h>
43 #include <sys/sysctl.h>
45 #include <machine/kdb.h>
46 #include <machine/pcb.h>
49 #include <machine/smp.h>
53 static void *kdb_jmpbufp = NULL;
54 struct kdb_dbbe *kdb_dbbe = NULL;
55 static struct pcb kdb_pcb;
56 struct pcb *kdb_thrctx = NULL;
57 struct thread *kdb_thread = NULL;
58 struct trapframe *kdb_frame = NULL;
60 KDB_BACKEND(null, NULL, NULL, NULL);
61 SET_DECLARE(kdb_dbbe_set, struct kdb_dbbe);
63 static int kdb_sysctl_available(SYSCTL_HANDLER_ARGS);
64 static int kdb_sysctl_current(SYSCTL_HANDLER_ARGS);
65 static int kdb_sysctl_enter(SYSCTL_HANDLER_ARGS);
66 static int kdb_sysctl_panic(SYSCTL_HANDLER_ARGS);
67 static int kdb_sysctl_trap(SYSCTL_HANDLER_ARGS);
68 static int kdb_sysctl_trap_code(SYSCTL_HANDLER_ARGS);
70 SYSCTL_NODE(_debug, OID_AUTO, kdb, CTLFLAG_RW, NULL, "KDB nodes");
72 SYSCTL_PROC(_debug_kdb, OID_AUTO, available, CTLTYPE_STRING | CTLFLAG_RD, NULL,
73 0, kdb_sysctl_available, "A", "list of available KDB backends");
75 SYSCTL_PROC(_debug_kdb, OID_AUTO, current, CTLTYPE_STRING | CTLFLAG_RW, NULL,
76 0, kdb_sysctl_current, "A", "currently selected KDB backend");
78 SYSCTL_PROC(_debug_kdb, OID_AUTO, enter, CTLTYPE_INT | CTLFLAG_RW, NULL, 0,
79 kdb_sysctl_enter, "I", "set to enter the debugger");
81 SYSCTL_PROC(_debug_kdb, OID_AUTO, panic, CTLTYPE_INT | CTLFLAG_RW, NULL, 0,
82 kdb_sysctl_panic, "I", "set to panic the kernel");
84 SYSCTL_PROC(_debug_kdb, OID_AUTO, trap, CTLTYPE_INT | CTLFLAG_RW, NULL, 0,
85 kdb_sysctl_trap, "I", "set to cause a page fault via data access");
87 SYSCTL_PROC(_debug_kdb, OID_AUTO, trap_code, CTLTYPE_INT | CTLFLAG_RW, NULL, 0,
88 kdb_sysctl_trap_code, "I", "set to cause a page fault via code access");
91 * Flag to indicate to debuggers why the debugger was entered.
93 const char * volatile kdb_why = KDB_WHY_UNSET;
96 kdb_sysctl_available(SYSCTL_HANDLER_ARGS)
98 struct kdb_dbbe **iter;
102 sbuf_new_for_sysctl(&sbuf, NULL, 64, req);
103 SET_FOREACH(iter, kdb_dbbe_set) {
104 if ((*iter)->dbbe_active == 0)
105 sbuf_printf(&sbuf, "%s ", (*iter)->dbbe_name);
107 error = sbuf_finish(&sbuf);
113 kdb_sysctl_current(SYSCTL_HANDLER_ARGS)
118 if (kdb_dbbe != NULL)
119 strlcpy(buf, kdb_dbbe->dbbe_name, sizeof(buf));
122 error = sysctl_handle_string(oidp, buf, sizeof(buf), req);
123 if (error != 0 || req->newptr == NULL)
127 return (kdb_dbbe_select(buf));
131 kdb_sysctl_enter(SYSCTL_HANDLER_ARGS)
135 error = sysctl_wire_old_buffer(req, sizeof(int));
138 error = sysctl_handle_int(oidp, &i, 0, req);
140 if (error != 0 || req->newptr == NULL)
144 kdb_enter(KDB_WHY_SYSCTL, "sysctl debug.kdb.enter");
149 kdb_sysctl_panic(SYSCTL_HANDLER_ARGS)
153 error = sysctl_wire_old_buffer(req, sizeof(int));
156 error = sysctl_handle_int(oidp, &i, 0, req);
158 if (error != 0 || req->newptr == NULL)
160 panic("kdb_sysctl_panic");
165 kdb_sysctl_trap(SYSCTL_HANDLER_ARGS)
168 int *addr = (int *)0x10;
170 error = sysctl_wire_old_buffer(req, sizeof(int));
173 error = sysctl_handle_int(oidp, &i, 0, req);
175 if (error != 0 || req->newptr == NULL)
181 kdb_sysctl_trap_code(SYSCTL_HANDLER_ARGS)
184 void (*fp)(u_int, u_int, u_int) = (void *)0xdeadc0de;
186 error = sysctl_wire_old_buffer(req, sizeof(int));
189 error = sysctl_handle_int(oidp, &i, 0, req);
191 if (error != 0 || req->newptr == NULL)
193 (*fp)(0x11111111, 0x22222222, 0x33333333);
198 kdb_panic(const char *msg)
203 other_cpus = all_cpus;
204 CPU_CLR(PCPU_GET(cpuid), &other_cpus);
205 stop_cpus_hard(other_cpus);
207 printf("KDB: panic\n");
215 printf("KDB: reboot requested\n");
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 */
233 #define KEY_CRTLP 16 /* ^P */
234 #define KEY_CRTLR 18 /* ^R */
236 /* States of th KDB "alternate break sequence" detecting state machine. */
238 KDB_ALT_BREAK_SEEN_NONE,
239 KDB_ALT_BREAK_SEEN_CR,
240 KDB_ALT_BREAK_SEEN_CR_TILDE,
244 kdb_alt_break(int key, int *state)
248 /* All states transition to KDB_ALT_BREAK_SEEN_CR on a CR. */
250 *state = KDB_ALT_BREAK_SEEN_CR;
256 case KDB_ALT_BREAK_SEEN_CR:
257 *state = KDB_ALT_BREAK_SEEN_NONE;
258 if (key == KEY_TILDE)
259 *state = KDB_ALT_BREAK_SEEN_CR_TILDE;
261 case KDB_ALT_BREAK_SEEN_CR_TILDE:
262 *state = KDB_ALT_BREAK_SEEN_NONE;
263 if (key == KEY_CRTLB)
264 brk = KDB_REQ_DEBUGGER;
265 else if (key == KEY_CRTLP)
267 else if (key == KEY_CRTLR)
268 brk = KDB_REQ_REBOOT;
270 case KDB_ALT_BREAK_SEEN_NONE:
272 *state = KDB_ALT_BREAK_SEEN_NONE;
279 * Print a backtrace of the calling thread. The backtrace is generated by
280 * the selected debugger, provided it supports backtraces. If no debugger
281 * is selected or the current debugger does not support backtraces, this
282 * function silently returns.
289 if (kdb_dbbe != NULL && kdb_dbbe->dbbe_trace != NULL) {
290 printf("KDB: stack backtrace:\n");
291 kdb_dbbe->dbbe_trace();
297 printf("KDB: stack backtrace:\n");
299 stack_print_ddb(&st);
305 * Set/change the current backend.
309 kdb_dbbe_select(const char *name)
311 struct kdb_dbbe *be, **iter;
313 SET_FOREACH(iter, kdb_dbbe_set) {
315 if (be->dbbe_active == 0 && strcmp(be->dbbe_name, name) == 0) {
324 * Enter the currently selected debugger. If a message has been provided,
325 * it is printed first. If the debugger does not support the enter method,
326 * it is entered by using breakpoint(), which enters the debugger through
327 * kdb_trap(). The 'why' argument will contain a more mechanically usable
328 * string than 'msg', and is relied upon by DDB scripting to identify the
329 * reason for entering the debugger so that the right script can be run.
332 kdb_enter(const char *why, const char *msg)
335 if (kdb_dbbe != NULL && kdb_active == 0) {
337 printf("KDB: enter: %s\n", msg);
340 kdb_why = KDB_WHY_UNSET;
345 * Initialize the kernel debugger interface.
351 struct kdb_dbbe *be, **iter;
357 SET_FOREACH(iter, kdb_dbbe_set) {
359 pri = (be->dbbe_init != NULL) ? be->dbbe_init() : -1;
360 be->dbbe_active = (pri >= 0) ? 0 : -1;
366 if (kdb_dbbe != NULL) {
367 printf("KDB: debugger backends:");
368 SET_FOREACH(iter, kdb_dbbe_set) {
370 if (be->dbbe_active == 0)
371 printf(" %s", be->dbbe_name);
374 printf("KDB: current backend: %s\n",
375 kdb_dbbe->dbbe_name);
384 kdb_jmpbuf(jmp_buf new)
397 if (!kdb_active || kdb_jmpbufp == NULL)
400 longjmp(kdb_jmpbufp, 1);
405 * Thread related support functions.
409 kdb_thr_ctx(struct thread *thr)
411 #if defined(SMP) && defined(KDB_STOPPEDPCB)
415 if (thr == curthread)
418 #if defined(SMP) && defined(KDB_STOPPEDPCB)
419 STAILQ_FOREACH(pc, &cpuhead, pc_allcpu) {
420 if (pc->pc_curthread == thr &&
421 CPU_ISSET(pc->pc_cpuid, &stopped_cpus))
422 return (KDB_STOPPEDPCB(pc));
425 return (thr->td_pcb);
434 p = LIST_FIRST(&allproc);
436 if (p->p_flag & P_INMEM) {
437 thr = FIRST_THREAD_IN_PROC(p);
441 p = LIST_NEXT(p, p_list);
447 kdb_thr_from_pid(pid_t pid)
451 p = LIST_FIRST(&allproc);
453 if (p->p_flag & P_INMEM && p->p_pid == pid)
454 return (FIRST_THREAD_IN_PROC(p));
455 p = LIST_NEXT(p, p_list);
461 kdb_thr_lookup(lwpid_t tid)
465 thr = kdb_thr_first();
466 while (thr != NULL && thr->td_tid != tid)
467 thr = kdb_thr_next(thr);
472 kdb_thr_next(struct thread *thr)
477 thr = TAILQ_NEXT(thr, td_plist);
481 p = LIST_NEXT(p, p_list);
482 if (p != NULL && (p->p_flag & P_INMEM))
483 thr = FIRST_THREAD_IN_PROC(p);
489 kdb_thr_select(struct thread *thr)
494 kdb_thrctx = kdb_thr_ctx(thr);
499 * Enter the debugger due to a trap.
503 kdb_trap(int type, int code, struct trapframe *tf)
513 if (be == NULL || be->dbbe_trap == NULL)
516 /* We reenter the debugger through kdb_reenter(). */
520 intr = intr_disable();
523 other_cpus = all_cpus;
524 CPU_CLR(PCPU_GET(cpuid), &other_cpus);
525 stop_cpus_hard(other_cpus);
532 /* Let MD code do its thing first... */
533 kdb_cpu_trap(type, code);
535 makectx(tf, &kdb_pcb);
536 kdb_thr_select(curthread);
539 handled = be->dbbe_trap(type, code);
543 if (be == NULL || be->dbbe_trap == NULL)
545 printf("Switching to %s back-end\n", be->dbbe_name);
551 restart_cpus(stopped_cpus);