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 static void *kdb_jmpbufp = NULL;
51 struct kdb_dbbe *kdb_dbbe = NULL;
52 static struct pcb kdb_pcb;
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, NULL,
70 0, kdb_sysctl_available, "A", "list of available KDB backends");
72 SYSCTL_PROC(_debug_kdb, OID_AUTO, current, CTLTYPE_STRING | CTLFLAG_RW, NULL,
73 0, kdb_sysctl_current, "A", "currently selected KDB backend");
75 SYSCTL_PROC(_debug_kdb, OID_AUTO, enter, CTLTYPE_INT | CTLFLAG_RW, NULL, 0,
76 kdb_sysctl_enter, "I", "set to enter the debugger");
78 SYSCTL_PROC(_debug_kdb, OID_AUTO, panic, CTLTYPE_INT | CTLFLAG_RW, NULL, 0,
79 kdb_sysctl_panic, "I", "set to panic the kernel");
81 SYSCTL_PROC(_debug_kdb, OID_AUTO, trap, CTLTYPE_INT | CTLFLAG_RW, NULL, 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, NULL, 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
91 * disabled. In order to maximize the chances of success, use a hard
95 static int kdb_stop_cpus = 1;
96 SYSCTL_INT(_debug_kdb, OID_AUTO, stop_cpus, CTLTYPE_INT | CTLFLAG_RW,
97 &kdb_stop_cpus, 0, "stop other CPUs when entering the debugger");
98 TUNABLE_INT("debug.kdb.stop_cpus", &kdb_stop_cpus);
102 * Flag to indicate to debuggers why the debugger was entered.
104 const char * volatile kdb_why = KDB_WHY_UNSET;
107 kdb_sysctl_available(SYSCTL_HANDLER_ARGS)
109 struct kdb_dbbe *be, **iter;
115 SET_FOREACH(iter, kdb_dbbe_set) {
117 if (be->dbbe_active == 0)
118 sz += strlen(be->dbbe_name) + 1;
121 avail = malloc(sz, M_TEMP, M_WAITOK);
125 SET_FOREACH(iter, kdb_dbbe_set) {
127 if (be->dbbe_active == 0) {
128 len = snprintf(p, sz, "%s ", be->dbbe_name);
133 KASSERT(sz >= 0, ("%s", __func__));
134 error = sysctl_handle_string(oidp, avail, 0, req);
140 kdb_sysctl_current(SYSCTL_HANDLER_ARGS)
145 if (kdb_dbbe != NULL) {
146 strncpy(buf, kdb_dbbe->dbbe_name, sizeof(buf));
147 buf[sizeof(buf) - 1] = '\0';
150 error = sysctl_handle_string(oidp, buf, sizeof(buf), req);
151 if (error != 0 || req->newptr == NULL)
155 return (kdb_dbbe_select(buf));
159 kdb_sysctl_enter(SYSCTL_HANDLER_ARGS)
163 error = sysctl_wire_old_buffer(req, sizeof(int));
166 error = sysctl_handle_int(oidp, &i, 0, req);
168 if (error != 0 || req->newptr == NULL)
172 kdb_enter(KDB_WHY_SYSCTL, "sysctl debug.kdb.enter");
177 kdb_sysctl_panic(SYSCTL_HANDLER_ARGS)
181 error = sysctl_wire_old_buffer(req, sizeof(int));
184 error = sysctl_handle_int(oidp, &i, 0, req);
186 if (error != 0 || req->newptr == NULL)
188 panic("kdb_sysctl_panic");
193 kdb_sysctl_trap(SYSCTL_HANDLER_ARGS)
196 int *addr = (int *)0x10;
198 error = sysctl_wire_old_buffer(req, sizeof(int));
201 error = sysctl_handle_int(oidp, &i, 0, req);
203 if (error != 0 || req->newptr == NULL)
209 kdb_sysctl_trap_code(SYSCTL_HANDLER_ARGS)
212 void (*fp)(u_int, u_int, u_int) = (void *)0xdeadc0de;
214 error = sysctl_wire_old_buffer(req, sizeof(int));
217 error = sysctl_handle_int(oidp, &i, 0, req);
219 if (error != 0 || req->newptr == NULL)
221 (*fp)(0x11111111, 0x22222222, 0x33333333);
226 kdb_panic(const char *msg)
230 stop_cpus_hard(PCPU_GET(other_cpus));
232 printf("KDB: panic\n");
240 printf("KDB: reboot requested\n");
245 * Solaris implements a new BREAK which is initiated by a character sequence
246 * CR ~ ^b which is similar to a familiar pattern used on Sun servers by the
249 * Note that this function may be called from almost anywhere, with interrupts
250 * disabled and with unknown locks held, so it must not access data other than
251 * its arguments. Its up to the caller to ensure that the state variable is
255 #define KEY_CR 13 /* CR '\r' */
256 #define KEY_TILDE 126 /* ~ */
257 #define KEY_CRTLB 2 /* ^B */
258 #define KEY_CRTLP 16 /* ^P */
259 #define KEY_CRTLR 18 /* ^R */
262 kdb_alt_break(int key, int *state)
273 if (key == KEY_TILDE)
277 if (key == KEY_CRTLB)
278 brk = KDB_REQ_DEBUGGER;
279 else if (key == KEY_CRTLP)
281 else if (key == KEY_CRTLR)
282 brk = KDB_REQ_REBOOT;
289 * Print a backtrace of the calling thread. The backtrace is generated by
290 * the selected debugger, provided it supports backtraces. If no debugger
291 * is selected or the current debugger does not support backtraces, this
292 * function silently returns.
299 if (kdb_dbbe != NULL && kdb_dbbe->dbbe_trace != NULL) {
300 printf("KDB: stack backtrace:\n");
301 kdb_dbbe->dbbe_trace();
306 * Set/change the current backend.
310 kdb_dbbe_select(const char *name)
312 struct kdb_dbbe *be, **iter;
314 SET_FOREACH(iter, kdb_dbbe_set) {
316 if (be->dbbe_active == 0 && strcmp(be->dbbe_name, name) == 0) {
325 * Enter the currently selected debugger. If a message has been provided,
326 * it is printed first. If the debugger does not support the enter method,
327 * it is entered by using breakpoint(), which enters the debugger through
328 * kdb_trap(). The 'why' argument will contain a more mechanically usable
329 * string than 'msg', and is relied upon by DDB scripting to identify the
330 * reason for entering the debugger so that the right script can be run.
333 kdb_enter(const char *why, const char *msg)
336 if (kdb_dbbe != NULL && kdb_active == 0) {
338 printf("KDB: enter: %s\n", msg);
341 kdb_why = KDB_WHY_UNSET;
346 * Initialize the kernel debugger interface.
352 struct kdb_dbbe *be, **iter;
358 SET_FOREACH(iter, kdb_dbbe_set) {
360 pri = (be->dbbe_init != NULL) ? be->dbbe_init() : -1;
361 be->dbbe_active = (pri >= 0) ? 0 : -1;
367 if (kdb_dbbe != NULL) {
368 printf("KDB: debugger backends:");
369 SET_FOREACH(iter, kdb_dbbe_set) {
371 if (be->dbbe_active == 0)
372 printf(" %s", be->dbbe_name);
375 printf("KDB: current backend: %s\n",
376 kdb_dbbe->dbbe_name);
385 kdb_jmpbuf(jmp_buf new)
398 if (!kdb_active || kdb_jmpbufp == NULL)
401 longjmp(kdb_jmpbufp, 1);
406 * Thread related support functions.
410 kdb_thr_ctx(struct thread *thr)
412 #if defined(SMP) && defined(KDB_STOPPEDPCB)
416 if (thr == curthread)
419 #if defined(SMP) && defined(KDB_STOPPEDPCB)
420 SLIST_FOREACH(pc, &cpuhead, pc_allcpu) {
421 if (pc->pc_curthread == thr && (stopped_cpus & pc->pc_cpumask))
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)
511 if (kdb_dbbe == NULL || kdb_dbbe->dbbe_trap == NULL)
514 /* We reenter the debugger through kdb_reenter(). */
518 intr = intr_disable();
521 if ((did_stop_cpus = kdb_stop_cpus) != 0)
522 stop_cpus_hard(PCPU_GET(other_cpus));
529 /* Let MD code do its thing first... */
530 kdb_cpu_trap(type, code);
532 makectx(tf, &kdb_pcb);
533 kdb_thr_select(curthread);
535 handled = kdb_dbbe->dbbe_trap(type, code);
541 restart_cpus(stopped_cpus);