The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]

FreeBSD/Linux Kernel Cross Reference
sys/kern/subr_kdb.c

Version: -  FREEBSD  -  FREEBSD-13-STABLE  -  FREEBSD-13-0  -  FREEBSD-12-STABLE  -  FREEBSD-12-0  -  FREEBSD-11-STABLE  -  FREEBSD-11-0  -  FREEBSD-10-STABLE  -  FREEBSD-10-0  -  FREEBSD-9-STABLE  -  FREEBSD-9-0  -  FREEBSD-8-STABLE  -  FREEBSD-8-0  -  FREEBSD-7-STABLE  -  FREEBSD-7-0  -  FREEBSD-6-STABLE  -  FREEBSD-6-0  -  FREEBSD-5-STABLE  -  FREEBSD-5-0  -  FREEBSD-4-STABLE  -  FREEBSD-3-STABLE  -  FREEBSD22  -  l41  -  OPENBSD  -  linux-2.6  -  MK84  -  PLAN9  -  xnu-8792 
SearchContext: -  none  -  3  -  10 

    1 /*-
    2  * Copyright (c) 2004 The FreeBSD Project
    3  * All rights reserved.
    4  *
    5  * Redistribution and use in source and binary forms, with or without
    6  * modification, are permitted provided that the following conditions
    7  * are met:
    8  *
    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.
   14  *
   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.
   25  */
   26 
   27 #include <sys/cdefs.h>
   28 __FBSDID("$FreeBSD$");
   29 
   30 #include "opt_kdb.h"
   31 
   32 #include <sys/param.h>
   33 #include <sys/systm.h>
   34 #include <sys/kdb.h>
   35 #include <sys/kernel.h>
   36 #include <sys/malloc.h>
   37 #include <sys/pcpu.h>
   38 #include <sys/proc.h>
   39 #include <sys/smp.h>
   40 #include <sys/sysctl.h>
   41 
   42 #include <machine/kdb.h>
   43 #include <machine/pcb.h>
   44 
   45 #ifdef SMP
   46 #include <machine/smp.h>
   47 #endif
   48 
   49 int kdb_active = 0;
   50 void *kdb_jmpbufp = NULL;
   51 struct kdb_dbbe *kdb_dbbe = NULL;
   52 struct pcb kdb_pcb;
   53 struct pcb *kdb_thrctx = NULL;
   54 struct thread *kdb_thread = NULL;
   55 struct trapframe *kdb_frame = NULL;
   56 
   57 KDB_BACKEND(null, NULL, NULL, NULL);
   58 SET_DECLARE(kdb_dbbe_set, struct kdb_dbbe);
   59 
   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);
   66 
   67 SYSCTL_NODE(_debug, OID_AUTO, kdb, CTLFLAG_RW, NULL, "KDB nodes");
   68 
   69 SYSCTL_PROC(_debug_kdb, OID_AUTO, available, CTLTYPE_STRING | CTLFLAG_RD, 0, 0,
   70     kdb_sysctl_available, "A", "list of available KDB backends");
   71 
   72 SYSCTL_PROC(_debug_kdb, OID_AUTO, current, CTLTYPE_STRING | CTLFLAG_RW, 0, 0,
   73     kdb_sysctl_current, "A", "currently selected KDB backend");
   74 
   75 SYSCTL_PROC(_debug_kdb, OID_AUTO, enter, CTLTYPE_INT | CTLFLAG_RW, 0, 0,
   76     kdb_sysctl_enter, "I", "set to enter the debugger");
   77 
   78 SYSCTL_PROC(_debug_kdb, OID_AUTO, panic, CTLTYPE_INT | CTLFLAG_RW, 0, 0,
   79     kdb_sysctl_panic, "I", "set to panic the kernel");
   80 
   81 SYSCTL_PROC(_debug_kdb, OID_AUTO, trap, CTLTYPE_INT | CTLFLAG_RW, 0, 0,
   82     kdb_sysctl_trap, "I", "set to cause a page fault via data access");
   83 
   84 SYSCTL_PROC(_debug_kdb, OID_AUTO, trap_code, CTLTYPE_INT | CTLFLAG_RW, 0, 0,
   85     kdb_sysctl_trap_code, "I", "set to cause a page fault via code access");
   86 
   87 /*
   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.
   92  */
   93 #ifdef SMP
   94 static int kdb_stop_cpus = 1;
   95 SYSCTL_INT(_debug_kdb, OID_AUTO, stop_cpus, CTLTYPE_INT | CTLFLAG_RW,
   96     &kdb_stop_cpus, 0, "stop other CPUs when entering the debugger");
   97 TUNABLE_INT("debug.kdb.stop_cpus", &kdb_stop_cpus);
   98 #endif
   99 
  100 static int
  101 kdb_sysctl_available(SYSCTL_HANDLER_ARGS)
  102 {
  103         struct kdb_dbbe *be, **iter;
  104         char *avail, *p;
  105         ssize_t len, sz;
  106         int error;
  107 
  108         sz = 0;
  109         SET_FOREACH(iter, kdb_dbbe_set) {
  110                 be = *iter;
  111                 if (be->dbbe_active == 0)
  112                         sz += strlen(be->dbbe_name) + 1;
  113         }
  114         sz++;
  115         avail = malloc(sz, M_TEMP, M_WAITOK);
  116         p = avail;
  117         *p = '\0';
  118 
  119         SET_FOREACH(iter, kdb_dbbe_set) {
  120                 be = *iter;
  121                 if (be->dbbe_active == 0) {
  122                         len = snprintf(p, sz, "%s ", be->dbbe_name);
  123                         p += len;
  124                         sz -= len;
  125                 }
  126         }
  127         KASSERT(sz >= 0, ("%s", __func__));
  128         error = sysctl_handle_string(oidp, avail, 0, req);
  129         free(avail, M_TEMP);
  130         return (error);
  131 }
  132 
  133 static int
  134 kdb_sysctl_current(SYSCTL_HANDLER_ARGS)
  135 {
  136         char buf[16];
  137         int error;
  138 
  139         if (kdb_dbbe != NULL) {
  140                 strncpy(buf, kdb_dbbe->dbbe_name, sizeof(buf));
  141                 buf[sizeof(buf) - 1] = '\0';
  142         } else
  143                 *buf = '\0';
  144         error = sysctl_handle_string(oidp, buf, sizeof(buf), req);
  145         if (error != 0 || req->newptr == NULL)
  146                 return (error);
  147         if (kdb_active)
  148                 return (EBUSY);
  149         return (kdb_dbbe_select(buf));
  150 }
  151 
  152 static int
  153 kdb_sysctl_enter(SYSCTL_HANDLER_ARGS)
  154 {
  155         int error, i;
  156 
  157         error = sysctl_wire_old_buffer(req, sizeof(int));
  158         if (error == 0) {
  159                 i = 0;
  160                 error = sysctl_handle_int(oidp, &i, 0, req);
  161         }
  162         if (error != 0 || req->newptr == NULL)
  163                 return (error);
  164         if (kdb_active)
  165                 return (EBUSY);
  166         kdb_enter("sysctl debug.kdb.enter");
  167         return (0);
  168 }
  169 
  170 static int
  171 kdb_sysctl_panic(SYSCTL_HANDLER_ARGS)
  172 {
  173         int error, i;
  174 
  175         error = sysctl_wire_old_buffer(req, sizeof(int));
  176         if (error == 0) {
  177                 i = 0;
  178                 error = sysctl_handle_int(oidp, &i, 0, req);
  179         }
  180         if (error != 0 || req->newptr == NULL)
  181                 return (error);
  182         panic("kdb_sysctl_panic");
  183         return (0);
  184 }
  185 
  186 static int
  187 kdb_sysctl_trap(SYSCTL_HANDLER_ARGS)
  188 {
  189         int error, i;
  190         int *addr = (int *)0x10;
  191 
  192         error = sysctl_wire_old_buffer(req, sizeof(int));
  193         if (error == 0) {
  194                 i = 0;
  195                 error = sysctl_handle_int(oidp, &i, 0, req);
  196         }
  197         if (error != 0 || req->newptr == NULL)
  198                 return (error);
  199         return (*addr);
  200 }
  201 
  202 static int
  203 kdb_sysctl_trap_code(SYSCTL_HANDLER_ARGS)
  204 {
  205         int error, i;
  206         void (*fp)(u_int, u_int, u_int) = (void *)0xdeadc0de;
  207 
  208         error = sysctl_wire_old_buffer(req, sizeof(int));
  209         if (error == 0) {
  210                 i = 0;
  211                 error = sysctl_handle_int(oidp, &i, 0, req);
  212         }
  213         if (error != 0 || req->newptr == NULL)
  214                 return (error);
  215         (*fp)(0x11111111, 0x22222222, 0x33333333);
  216         return (0);
  217 }
  218 
  219 /*
  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
  222  * Remote Console.
  223  *
  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
  227  * consistent.
  228  */
  229 
  230 #define KEY_CR          13      /* CR '\r' */
  231 #define KEY_TILDE       126     /* ~ */
  232 #define KEY_CRTLB       2       /* ^B */
  233 
  234 int
  235 kdb_alt_break(int key, int *state)
  236 {
  237         int brk;
  238 
  239         brk = 0;
  240         switch (key) {
  241         case KEY_CR:
  242                 *state = KEY_TILDE;
  243                 break;
  244         case KEY_TILDE:
  245                 *state = (*state == KEY_TILDE) ? KEY_CRTLB : 0;
  246                 break;
  247         case KEY_CRTLB:
  248                 if (*state == KEY_CRTLB)
  249                         brk = 1;
  250                 /* FALLTHROUGH */
  251         default:
  252                 *state = 0;
  253                 break;
  254         }
  255         return (brk);
  256 }
  257 
  258 /*
  259  * Print a backtrace of the calling thread. The backtrace is generated by
  260  * the selected debugger, provided it supports backtraces. If no debugger
  261  * is selected or the current debugger does not support backtraces, this
  262  * function silently returns.
  263  */
  264 
  265 void
  266 kdb_backtrace()
  267 {
  268 
  269         if (kdb_dbbe != NULL && kdb_dbbe->dbbe_trace != NULL) {
  270                 printf("KDB: stack backtrace:\n");
  271                 kdb_dbbe->dbbe_trace();
  272         }
  273 }
  274 
  275 /*
  276  * Set/change the current backend.
  277  */
  278 
  279 int
  280 kdb_dbbe_select(const char *name)
  281 {
  282         struct kdb_dbbe *be, **iter;
  283 
  284         SET_FOREACH(iter, kdb_dbbe_set) {
  285                 be = *iter;
  286                 if (be->dbbe_active == 0 && strcmp(be->dbbe_name, name) == 0) {
  287                         kdb_dbbe = be;
  288                         return (0);
  289                 }
  290         }
  291         return (EINVAL);
  292 }
  293 
  294 /*
  295  * Enter the currently selected debugger. If a message has been provided,
  296  * it is printed first. If the debugger does not support the enter method,
  297  * it is entered by using breakpoint(), which enters the debugger through
  298  * kdb_trap().
  299  */
  300 
  301 void
  302 kdb_enter(const char *msg)
  303 {
  304 
  305         if (kdb_dbbe != NULL && kdb_active == 0) {
  306                 if (msg != NULL)
  307                         printf("KDB: enter: %s\n", msg);
  308                 breakpoint();
  309         }
  310 }
  311 
  312 /*
  313  * Initialize the kernel debugger interface.
  314  */
  315 
  316 void
  317 kdb_init()
  318 {
  319         struct kdb_dbbe *be, **iter;
  320         int cur_pri, pri;
  321 
  322         kdb_active = 0;
  323         kdb_dbbe = NULL;
  324         cur_pri = -1;
  325         SET_FOREACH(iter, kdb_dbbe_set) {
  326                 be = *iter;
  327                 pri = (be->dbbe_init != NULL) ? be->dbbe_init() : -1;
  328                 be->dbbe_active = (pri >= 0) ? 0 : -1;
  329                 if (pri > cur_pri) {
  330                         cur_pri = pri;
  331                         kdb_dbbe = be;
  332                 }
  333         }
  334         if (kdb_dbbe != NULL) {
  335                 printf("KDB: debugger backends:");
  336                 SET_FOREACH(iter, kdb_dbbe_set) {
  337                         be = *iter;
  338                         if (be->dbbe_active == 0)
  339                                 printf(" %s", be->dbbe_name);
  340                 }
  341                 printf("\n");
  342                 printf("KDB: current backend: %s\n",
  343                     kdb_dbbe->dbbe_name);
  344         }
  345 }
  346 
  347 /*
  348  * Handle contexts.
  349  */
  350 
  351 void *
  352 kdb_jmpbuf(jmp_buf new)
  353 {
  354         void *old;
  355 
  356         old = kdb_jmpbufp;
  357         kdb_jmpbufp = new;
  358         return (old);
  359 }
  360 
  361 void
  362 kdb_reenter(void)
  363 {
  364 
  365         if (!kdb_active || kdb_jmpbufp == NULL)
  366                 return;
  367 
  368         longjmp(kdb_jmpbufp, 1);
  369         /* NOTREACHED */
  370 }
  371 
  372 /*
  373  * Thread related support functions.
  374  */
  375 
  376 struct pcb *
  377 kdb_thr_ctx(struct thread *thr)
  378 {  
  379 #if defined(SMP) && defined(KDB_STOPPEDPCB)
  380         struct pcpu *pc;
  381 #endif
  382  
  383         if (thr == curthread) 
  384                 return (&kdb_pcb);
  385 
  386 #if defined(SMP) && defined(KDB_STOPPEDPCB)
  387         SLIST_FOREACH(pc, &cpuhead, pc_allcpu)  {
  388                 if (pc->pc_curthread == thr && (stopped_cpus & pc->pc_cpumask))
  389                         return (KDB_STOPPEDPCB(pc));
  390         }
  391 #endif
  392         return (thr->td_pcb);
  393 }
  394 
  395 struct thread *
  396 kdb_thr_first(void)
  397 {
  398         struct proc *p;
  399         struct thread *thr;
  400 
  401         p = LIST_FIRST(&allproc);
  402         while (p != NULL) {
  403                 if (p->p_flag & P_INMEM) {
  404                         thr = FIRST_THREAD_IN_PROC(p);
  405                         if (thr != NULL)
  406                                 return (thr);
  407                 }
  408                 p = LIST_NEXT(p, p_list);
  409         }
  410         return (NULL);
  411 }
  412 
  413 struct thread *
  414 kdb_thr_from_pid(pid_t pid)
  415 {
  416         struct proc *p;
  417 
  418         p = LIST_FIRST(&allproc);
  419         while (p != NULL) {
  420                 if (p->p_flag & P_INMEM && p->p_pid == pid)
  421                         return (FIRST_THREAD_IN_PROC(p));
  422                 p = LIST_NEXT(p, p_list);
  423         }
  424         return (NULL);
  425 }
  426 
  427 struct thread *
  428 kdb_thr_lookup(lwpid_t tid)
  429 {
  430         struct thread *thr;
  431 
  432         thr = kdb_thr_first();
  433         while (thr != NULL && thr->td_tid != tid)
  434                 thr = kdb_thr_next(thr);
  435         return (thr);
  436 }
  437 
  438 struct thread *
  439 kdb_thr_next(struct thread *thr)
  440 {
  441         struct proc *p;
  442 
  443         p = thr->td_proc;
  444         thr = TAILQ_NEXT(thr, td_plist);
  445         do {
  446                 if (thr != NULL)
  447                         return (thr);
  448                 p = LIST_NEXT(p, p_list);
  449                 if (p != NULL && (p->p_flag & P_INMEM))
  450                         thr = FIRST_THREAD_IN_PROC(p);
  451         } while (p != NULL);
  452         return (NULL);
  453 }
  454 
  455 int
  456 kdb_thr_select(struct thread *thr)
  457 {
  458         if (thr == NULL)
  459                 return (EINVAL);
  460         kdb_thread = thr;
  461         kdb_thrctx = kdb_thr_ctx(thr);
  462         return (0);
  463 }
  464 
  465 /*
  466  * Enter the debugger due to a trap.
  467  */
  468 
  469 int
  470 kdb_trap(int type, int code, struct trapframe *tf)
  471 {
  472         register_t intr;
  473 #ifdef SMP
  474         int did_stop_cpus;
  475 #endif
  476         int handled;
  477 
  478         if (kdb_dbbe == NULL || kdb_dbbe->dbbe_trap == NULL)
  479                 return (0);
  480 
  481         /* We reenter the debugger through kdb_reenter(). */
  482         if (kdb_active)
  483                 return (0);
  484 
  485         intr = intr_disable();
  486 
  487 #ifdef SMP
  488         if ((did_stop_cpus = kdb_stop_cpus) != 0)
  489                 stop_cpus(PCPU_GET(other_cpus));
  490 #endif
  491 
  492         kdb_active++;
  493 
  494         kdb_frame = tf;
  495 
  496         /* Let MD code do its thing first... */
  497         kdb_cpu_trap(type, code);
  498 
  499         makectx(tf, &kdb_pcb);
  500         kdb_thr_select(curthread);
  501 
  502         handled = kdb_dbbe->dbbe_trap(type, code);
  503 
  504         kdb_active--;
  505 
  506 #ifdef SMP
  507         if (did_stop_cpus)
  508                 restart_cpus(stopped_cpus);
  509 #endif
  510 
  511         intr_restore(intr);
  512 
  513         return (handled);
  514 }

Cache object: deb393ba2e457ce2a7c8ac307f6c37de


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]


This page is part of the FreeBSD/Linux Linux Kernel Cross-Reference, and was automatically generated using a modified version of the LXR engine.