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>
41 #include <sys/stack.h>
42 #include <sys/sysctl.h>
44 #include <machine/kdb.h>
45 #include <machine/pcb.h>
48 #include <machine/smp.h>
52 static void *kdb_jmpbufp = NULL;
53 struct kdb_dbbe *kdb_dbbe = NULL;
54 static struct pcb kdb_pcb;
55 struct pcb *kdb_thrctx = NULL;
56 struct thread *kdb_thread = NULL;
57 struct trapframe *kdb_frame = NULL;
59 KDB_BACKEND(null, NULL, NULL, NULL);
60 SET_DECLARE(kdb_dbbe_set, struct kdb_dbbe);
62 static int kdb_sysctl_available(SYSCTL_HANDLER_ARGS);
63 static int kdb_sysctl_current(SYSCTL_HANDLER_ARGS);
64 static int kdb_sysctl_enter(SYSCTL_HANDLER_ARGS);
65 static int kdb_sysctl_panic(SYSCTL_HANDLER_ARGS);
66 static int kdb_sysctl_trap(SYSCTL_HANDLER_ARGS);
67 static int kdb_sysctl_trap_code(SYSCTL_HANDLER_ARGS);
69 SYSCTL_NODE(_debug, OID_AUTO, kdb, CTLFLAG_RW, NULL, "KDB nodes");
71 SYSCTL_PROC(_debug_kdb, OID_AUTO, available, CTLTYPE_STRING | CTLFLAG_RD, NULL,
72 0, kdb_sysctl_available, "A", "list of available KDB backends");
74 SYSCTL_PROC(_debug_kdb, OID_AUTO, current, CTLTYPE_STRING | CTLFLAG_RW, NULL,
75 0, kdb_sysctl_current, "A", "currently selected KDB backend");
77 SYSCTL_PROC(_debug_kdb, OID_AUTO, enter, CTLTYPE_INT | CTLFLAG_RW, NULL, 0,
78 kdb_sysctl_enter, "I", "set to enter the debugger");
80 SYSCTL_PROC(_debug_kdb, OID_AUTO, panic, CTLTYPE_INT | CTLFLAG_RW, NULL, 0,
81 kdb_sysctl_panic, "I", "set to panic the kernel");
83 SYSCTL_PROC(_debug_kdb, OID_AUTO, trap, CTLTYPE_INT | CTLFLAG_RW, NULL, 0,
84 kdb_sysctl_trap, "I", "set to cause a page fault via data access");
86 SYSCTL_PROC(_debug_kdb, OID_AUTO, trap_code, CTLTYPE_INT | CTLFLAG_RW, NULL, 0,
87 kdb_sysctl_trap_code, "I", "set to cause a page fault via code access");
90 * Flag indicating whether or not to IPI the other CPUs to stop them on
91 * entering the debugger. Sometimes, this will result in a deadlock as
92 * stop_cpus() waits for the other cpus to stop, so we allow it to be
93 * disabled. In order to maximize the chances of success, use a hard
97 static int kdb_stop_cpus = 1;
98 SYSCTL_INT(_debug_kdb, OID_AUTO, stop_cpus, CTLFLAG_RW | CTLFLAG_TUN,
99 &kdb_stop_cpus, 0, "stop other CPUs when entering the debugger");
100 TUNABLE_INT("debug.kdb.stop_cpus", &kdb_stop_cpus);
104 * Flag to indicate to debuggers why the debugger was entered.
106 const char * volatile kdb_why = KDB_WHY_UNSET;
109 kdb_sysctl_available(SYSCTL_HANDLER_ARGS)
111 struct kdb_dbbe *be, **iter;
117 SET_FOREACH(iter, kdb_dbbe_set) {
119 if (be->dbbe_active == 0)
120 sz += strlen(be->dbbe_name) + 1;
123 avail = malloc(sz, M_TEMP, M_WAITOK);
127 SET_FOREACH(iter, kdb_dbbe_set) {
129 if (be->dbbe_active == 0) {
130 len = snprintf(p, sz, "%s ", be->dbbe_name);
135 KASSERT(sz >= 0, ("%s", __func__));
136 error = sysctl_handle_string(oidp, avail, 0, req);
142 kdb_sysctl_current(SYSCTL_HANDLER_ARGS)
147 if (kdb_dbbe != NULL) {
148 strncpy(buf, kdb_dbbe->dbbe_name, sizeof(buf));
149 buf[sizeof(buf) - 1] = '\0';
152 error = sysctl_handle_string(oidp, buf, sizeof(buf), req);
153 if (error != 0 || req->newptr == NULL)
157 return (kdb_dbbe_select(buf));
161 kdb_sysctl_enter(SYSCTL_HANDLER_ARGS)
165 error = sysctl_wire_old_buffer(req, sizeof(int));
168 error = sysctl_handle_int(oidp, &i, 0, req);
170 if (error != 0 || req->newptr == NULL)
174 kdb_enter(KDB_WHY_SYSCTL, "sysctl debug.kdb.enter");
179 kdb_sysctl_panic(SYSCTL_HANDLER_ARGS)
183 error = sysctl_wire_old_buffer(req, sizeof(int));
186 error = sysctl_handle_int(oidp, &i, 0, req);
188 if (error != 0 || req->newptr == NULL)
190 panic("kdb_sysctl_panic");
195 kdb_sysctl_trap(SYSCTL_HANDLER_ARGS)
198 int *addr = (int *)0x10;
200 error = sysctl_wire_old_buffer(req, sizeof(int));
203 error = sysctl_handle_int(oidp, &i, 0, req);
205 if (error != 0 || req->newptr == NULL)
211 kdb_sysctl_trap_code(SYSCTL_HANDLER_ARGS)
214 void (*fp)(u_int, u_int, u_int) = (void *)0xdeadc0de;
216 error = sysctl_wire_old_buffer(req, sizeof(int));
219 error = sysctl_handle_int(oidp, &i, 0, req);
221 if (error != 0 || req->newptr == NULL)
223 (*fp)(0x11111111, 0x22222222, 0x33333333);
228 kdb_panic(const char *msg)
232 stop_cpus_hard(PCPU_GET(other_cpus));
234 printf("KDB: panic\n");
242 printf("KDB: reboot requested\n");
247 * Solaris implements a new BREAK which is initiated by a character sequence
248 * CR ~ ^b which is similar to a familiar pattern used on Sun servers by the
251 * Note that this function may be called from almost anywhere, with interrupts
252 * disabled and with unknown locks held, so it must not access data other than
253 * its arguments. Its up to the caller to ensure that the state variable is
257 #define KEY_CR 13 /* CR '\r' */
258 #define KEY_TILDE 126 /* ~ */
259 #define KEY_CRTLB 2 /* ^B */
260 #define KEY_CRTLP 16 /* ^P */
261 #define KEY_CRTLR 18 /* ^R */
264 kdb_alt_break(int key, int *state)
275 if (key == KEY_TILDE)
279 if (key == KEY_CRTLB)
280 brk = KDB_REQ_DEBUGGER;
281 else if (key == KEY_CRTLP)
283 else if (key == KEY_CRTLR)
284 brk = KDB_REQ_REBOOT;
291 * Print a backtrace of the calling thread. The backtrace is generated by
292 * the selected debugger, provided it supports backtraces. If no debugger
293 * is selected or the current debugger does not support backtraces, this
294 * function silently returns.
301 if (kdb_dbbe != NULL && kdb_dbbe->dbbe_trace != NULL) {
302 printf("KDB: stack backtrace:\n");
303 kdb_dbbe->dbbe_trace();
309 printf("KDB: stack backtrace:\n");
311 stack_print_ddb(&st);
317 * Set/change the current backend.
321 kdb_dbbe_select(const char *name)
323 struct kdb_dbbe *be, **iter;
325 SET_FOREACH(iter, kdb_dbbe_set) {
327 if (be->dbbe_active == 0 && strcmp(be->dbbe_name, name) == 0) {
336 * Enter the currently selected debugger. If a message has been provided,
337 * it is printed first. If the debugger does not support the enter method,
338 * it is entered by using breakpoint(), which enters the debugger through
339 * kdb_trap(). The 'why' argument will contain a more mechanically usable
340 * string than 'msg', and is relied upon by DDB scripting to identify the
341 * reason for entering the debugger so that the right script can be run.
344 kdb_enter(const char *why, const char *msg)
347 if (kdb_dbbe != NULL && kdb_active == 0) {
349 printf("KDB: enter: %s\n", msg);
352 kdb_why = KDB_WHY_UNSET;
357 * Initialize the kernel debugger interface.
363 struct kdb_dbbe *be, **iter;
369 SET_FOREACH(iter, kdb_dbbe_set) {
371 pri = (be->dbbe_init != NULL) ? be->dbbe_init() : -1;
372 be->dbbe_active = (pri >= 0) ? 0 : -1;
378 if (kdb_dbbe != NULL) {
379 printf("KDB: debugger backends:");
380 SET_FOREACH(iter, kdb_dbbe_set) {
382 if (be->dbbe_active == 0)
383 printf(" %s", be->dbbe_name);
386 printf("KDB: current backend: %s\n",
387 kdb_dbbe->dbbe_name);
396 kdb_jmpbuf(jmp_buf new)
409 if (!kdb_active || kdb_jmpbufp == NULL)
412 longjmp(kdb_jmpbufp, 1);
417 * Thread related support functions.
421 kdb_thr_ctx(struct thread *thr)
423 #if defined(SMP) && defined(KDB_STOPPEDPCB)
427 if (thr == curthread)
430 #if defined(SMP) && defined(KDB_STOPPEDPCB)
431 SLIST_FOREACH(pc, &cpuhead, pc_allcpu) {
432 if (pc->pc_curthread == thr && (stopped_cpus & pc->pc_cpumask))
433 return (KDB_STOPPEDPCB(pc));
436 return (thr->td_pcb);
445 p = LIST_FIRST(&allproc);
447 if (p->p_flag & P_INMEM) {
448 thr = FIRST_THREAD_IN_PROC(p);
452 p = LIST_NEXT(p, p_list);
458 kdb_thr_from_pid(pid_t pid)
462 p = LIST_FIRST(&allproc);
464 if (p->p_flag & P_INMEM && p->p_pid == pid)
465 return (FIRST_THREAD_IN_PROC(p));
466 p = LIST_NEXT(p, p_list);
472 kdb_thr_lookup(lwpid_t tid)
476 thr = kdb_thr_first();
477 while (thr != NULL && thr->td_tid != tid)
478 thr = kdb_thr_next(thr);
483 kdb_thr_next(struct thread *thr)
488 thr = TAILQ_NEXT(thr, td_plist);
492 p = LIST_NEXT(p, p_list);
493 if (p != NULL && (p->p_flag & P_INMEM))
494 thr = FIRST_THREAD_IN_PROC(p);
500 kdb_thr_select(struct thread *thr)
505 kdb_thrctx = kdb_thr_ctx(thr);
510 * Enter the debugger due to a trap.
514 kdb_trap(int type, int code, struct trapframe *tf)
522 if (kdb_dbbe == NULL || kdb_dbbe->dbbe_trap == NULL)
525 /* We reenter the debugger through kdb_reenter(). */
529 intr = intr_disable();
532 if ((did_stop_cpus = kdb_stop_cpus) != 0)
533 stop_cpus_hard(PCPU_GET(other_cpus));
540 /* Let MD code do its thing first... */
541 kdb_cpu_trap(type, code);
543 makectx(tf, &kdb_pcb);
544 kdb_thr_select(curthread);
546 handled = kdb_dbbe->dbbe_trap(type, code);
552 restart_cpus(stopped_cpus);