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 #if defined (__i386__) || defined(__amd64__) || defined(__sparc64__) || defined(__alpha__)
47 #define HAVE_STOPPEDPCBS
48 #include <machine/smp.h>
53 void *kdb_jmpbufp = NULL;
54 struct kdb_dbbe *kdb_dbbe = NULL;
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);
69 SYSCTL_NODE(_debug, OID_AUTO, kdb, CTLFLAG_RW, NULL, "KDB nodes");
71 SYSCTL_PROC(_debug_kdb, OID_AUTO, available, CTLTYPE_STRING | CTLFLAG_RD, 0, 0,
72 kdb_sysctl_available, "A", "list of available KDB backends");
74 SYSCTL_PROC(_debug_kdb, OID_AUTO, current, CTLTYPE_STRING | CTLFLAG_RW, 0, 0,
75 kdb_sysctl_current, "A", "currently selected KDB backend");
77 SYSCTL_PROC(_debug_kdb, OID_AUTO, enter, CTLTYPE_INT | CTLFLAG_RW, 0, 0,
78 kdb_sysctl_enter, "I", "set to enter the debugger");
80 SYSCTL_PROC(_debug_kdb, OID_AUTO, panic, CTLTYPE_INT | CTLFLAG_RW, 0, 0,
81 kdb_sysctl_panic, "I", "set to panic the kernel");
83 SYSCTL_PROC(_debug_kdb, OID_AUTO, trap, CTLTYPE_INT | CTLFLAG_RW, 0, 0,
84 kdb_sysctl_trap, "I", "set cause a page fault");
87 * Flag indicating whether or not to IPI the other CPUs to stop them on
88 * entering the debugger. Sometimes, this will result in a deadlock as
89 * stop_cpus() waits for the other cpus to stop, so we allow it to be
93 static int kdb_stop_cpus = 1;
94 SYSCTL_INT(_debug_kdb, OID_AUTO, stop_cpus, CTLTYPE_INT | CTLFLAG_RW,
95 &kdb_stop_cpus, 0, "");
96 TUNABLE_INT("debug.kdb.stop_cpus", &kdb_stop_cpus);
100 kdb_sysctl_available(SYSCTL_HANDLER_ARGS)
102 struct kdb_dbbe *be, **iter;
108 SET_FOREACH(iter, kdb_dbbe_set) {
110 if (be->dbbe_active == 0)
111 sz += strlen(be->dbbe_name) + 1;
114 avail = malloc(sz, M_TEMP, M_WAITOK);
118 SET_FOREACH(iter, kdb_dbbe_set) {
120 if (be->dbbe_active == 0) {
121 len = snprintf(p, sz, "%s ", be->dbbe_name);
126 KASSERT(sz >= 0, ("%s", __func__));
127 error = sysctl_handle_string(oidp, avail, 0, req);
133 kdb_sysctl_current(SYSCTL_HANDLER_ARGS)
138 if (kdb_dbbe != NULL) {
139 strncpy(buf, kdb_dbbe->dbbe_name, sizeof(buf));
140 buf[sizeof(buf) - 1] = '\0';
143 error = sysctl_handle_string(oidp, buf, sizeof(buf), req);
144 if (error != 0 || req->newptr == NULL)
148 return (kdb_dbbe_select(buf));
152 kdb_sysctl_enter(SYSCTL_HANDLER_ARGS)
156 error = sysctl_wire_old_buffer(req, sizeof(int));
159 error = sysctl_handle_int(oidp, &i, 0, req);
161 if (error != 0 || req->newptr == NULL)
165 kdb_enter("sysctl debug.kdb.enter");
170 kdb_sysctl_panic(SYSCTL_HANDLER_ARGS)
174 error = sysctl_wire_old_buffer(req, sizeof(int));
177 error = sysctl_handle_int(oidp, &i, 0, req);
179 if (error != 0 || req->newptr == NULL)
181 panic("kdb_sysctl_panic");
186 kdb_sysctl_trap(SYSCTL_HANDLER_ARGS)
189 int *addr = (int *)0x10;
191 error = sysctl_wire_old_buffer(req, sizeof(int));
194 error = sysctl_handle_int(oidp, &i, 0, req);
196 if (error != 0 || req->newptr == NULL)
202 * Solaris implements a new BREAK which is initiated by a character sequence
203 * CR ~ ^b which is similar to a familiar pattern used on Sun servers by the
206 * Note that this function may be called from almost anywhere, with interrupts
207 * disabled and with unknown locks held, so it must not access data other than
208 * its arguments. Its up to the caller to ensure that the state variable is
212 #define KEY_CR 13 /* CR '\r' */
213 #define KEY_TILDE 126 /* ~ */
214 #define KEY_CRTLB 2 /* ^B */
217 kdb_alt_break(int key, int *state)
227 *state = (*state == KEY_TILDE) ? KEY_CRTLB : 0;
230 if (*state == KEY_CRTLB)
241 * Print a backtrace of the calling thread. The backtrace is generated by
242 * the selected debugger, provided it supports backtraces. If no debugger
243 * is selected or the current debugger does not support backtraces, this
244 * function silently returns.
251 if (kdb_dbbe != NULL && kdb_dbbe->dbbe_trace != NULL) {
252 printf("KDB: stack backtrace:\n");
253 kdb_dbbe->dbbe_trace();
258 * Set/change the current backend.
262 kdb_dbbe_select(const char *name)
264 struct kdb_dbbe *be, **iter;
266 SET_FOREACH(iter, kdb_dbbe_set) {
268 if (be->dbbe_active == 0 && strcmp(be->dbbe_name, name) == 0) {
277 * Enter the currently selected debugger. If a message has been provided,
278 * it is printed first. If the debugger does not support the enter method,
279 * it is entered by using breakpoint(), which enters the debugger through
284 kdb_enter(const char *msg)
287 if (kdb_dbbe != NULL && kdb_active == 0) {
289 printf("KDB: enter: %s\n", msg);
295 * Initialize the kernel debugger interface.
301 struct kdb_dbbe *be, **iter;
307 SET_FOREACH(iter, kdb_dbbe_set) {
309 pri = (be->dbbe_init != NULL) ? be->dbbe_init() : -1;
310 be->dbbe_active = (pri >= 0) ? 0 : -1;
316 if (kdb_dbbe != NULL) {
317 printf("KDB: debugger backends:");
318 SET_FOREACH(iter, kdb_dbbe_set) {
320 if (be->dbbe_active == 0)
321 printf(" %s", be->dbbe_name);
324 printf("KDB: current backend: %s\n",
325 kdb_dbbe->dbbe_name);
334 kdb_jmpbuf(jmp_buf new)
347 if (!kdb_active || kdb_jmpbufp == NULL)
350 longjmp(kdb_jmpbufp, 1);
355 * Thread related support functions.
359 kdb_thr_ctx(struct thread *thr)
361 #ifdef HAVE_STOPPEDPCBS
366 if (thr == curthread)
369 #ifdef HAVE_STOPPEDPCBS
370 SLIST_FOREACH(pc, &cpuhead, pc_allcpu) {
371 cpuid = pc->pc_cpuid;
372 if (pc->pc_curthread == thr && (stopped_cpus & (1 << cpuid)))
373 return (&stoppcbs[cpuid]);
376 return (thr->td_pcb);
385 p = LIST_FIRST(&allproc);
387 if (p->p_sflag & PS_INMEM) {
388 thr = FIRST_THREAD_IN_PROC(p);
392 p = LIST_NEXT(p, p_list);
398 kdb_thr_from_pid(pid_t pid)
402 p = LIST_FIRST(&allproc);
404 if (p->p_sflag & PS_INMEM && p->p_pid == pid)
405 return (FIRST_THREAD_IN_PROC(p));
406 p = LIST_NEXT(p, p_list);
412 kdb_thr_lookup(lwpid_t tid)
416 thr = kdb_thr_first();
417 while (thr != NULL && thr->td_tid != tid)
418 thr = kdb_thr_next(thr);
423 kdb_thr_next(struct thread *thr)
428 thr = TAILQ_NEXT(thr, td_plist);
432 p = LIST_NEXT(p, p_list);
433 if (p != NULL && (p->p_sflag & PS_INMEM))
434 thr = FIRST_THREAD_IN_PROC(p);
440 kdb_thr_select(struct thread *thr)
445 kdb_thrctx = kdb_thr_ctx(thr);
450 * Enter the debugger due to a trap.
454 kdb_trap(int type, int code, struct trapframe *tf)
461 if (kdb_dbbe == NULL || kdb_dbbe->dbbe_trap == NULL)
464 /* We reenter the debugger through kdb_reenter(). */
473 if ((did_stop_cpus = kdb_stop_cpus) != 0)
474 stop_cpus(PCPU_GET(other_cpus));
479 /* Let MD code do its thing first... */
480 kdb_cpu_trap(type, code);
482 makectx(tf, &kdb_pcb);
483 kdb_thr_select(curthread);
485 handled = kdb_dbbe->dbbe_trap(type, code);
489 restart_cpus(stopped_cpus);