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/gdb/gdb_cons.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  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
    3  *
    4  * Copyright (c) 2006 Sam Leffler
    5  * All rights reserved.
    6  *
    7  * Redistribution and use in source and binary forms, with or without
    8  * modification, are permitted provided that the following conditions
    9  * are met:
   10  *
   11  * 1. Redistributions of source code must retain the above copyright
   12  *    notice, this list of conditions and the following disclaimer.
   13  * 2. Redistributions in binary form must reproduce the above copyright
   14  *    notice, this list of conditions and the following disclaimer in the
   15  *    documentation and/or other materials provided with the distribution.
   16  *
   17  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
   18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
   20  * IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT,
   21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
   22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
   26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   27  */
   28 
   29 /* 
   30  * Support for redirecting console msgs to gdb.  We register
   31  * a pseudo console to hook cnputc and send stuff to the gdb
   32  * port.  The only trickiness here is buffering output so this
   33  * isn't dog slow.
   34  */
   35 
   36 #include <sys/cdefs.h>
   37 __FBSDID("$FreeBSD$");
   38 
   39 #include <sys/param.h>
   40 #include <sys/systm.h>
   41 #include <sys/cons.h>
   42 #include <sys/kdb.h>
   43 #include <sys/kernel.h>
   44 #include <sys/malloc.h>
   45 #include <sys/reboot.h>
   46 #include <sys/sysctl.h>
   47 
   48 #include <machine/gdb_machdep.h>
   49 #include <machine/kdb.h>
   50 
   51 #include <gdb/gdb.h>
   52 #include <gdb/gdb_int.h>
   53 
   54 struct gdbcons {
   55         int     npending;
   56         /* /2 for hex conversion, -6 for protocol glue */
   57         char    buf[GDB_BUFSZ/2 - 6];
   58         struct callout flush;
   59 };
   60 static struct gdbcons state = { -1 };
   61 
   62 static  int gdbcons_enable = 0;
   63 SYSCTL_INT(_debug_gdb, OID_AUTO, cons, CTLFLAG_RWTUN, &gdbcons_enable, 0,
   64         "copy console messages to GDB");
   65 /* Legacy sysctl alias */
   66 SYSCTL_INT(_debug, OID_AUTO, gdbcons, CTLFLAG_RWTUN, &gdbcons_enable,
   67         0, "copy console messages to GDB");
   68 
   69 static void
   70 gdb_cnprobe(struct consdev *cp)
   71 {
   72         sprintf(cp->cn_name, "gdb");
   73         cp->cn_pri = CN_LOW;            /* XXX no way to say "write only" */
   74 }
   75 
   76 static void
   77 gdb_cninit(struct consdev *cp)
   78 {
   79         struct gdbcons *c = &state;
   80 
   81         /* setup tx buffer and callout */
   82         if (c->npending == -1) {
   83                 c->npending = 0;
   84                 callout_init(&c->flush, 1);
   85                 cp->cn_arg = c;
   86         }
   87 }
   88 
   89 static void
   90 gdb_cnterm(struct consdev *cp)
   91 {
   92 }
   93 
   94 static void
   95 gdb_cngrab(struct consdev *cp)
   96 {
   97 }
   98 
   99 static void
  100 gdb_cnungrab(struct consdev *cp)
  101 {
  102 }
  103 
  104 static int
  105 gdb_cngetc(struct consdev *cp)
  106 {
  107         return -1;
  108 }
  109 
  110 static void
  111 gdb_tx_puthex(int c)
  112 {
  113         const char *hex = "0123456789abcdef";
  114 
  115         gdb_tx_char(hex[(c>>4)&0xf]);
  116         gdb_tx_char(hex[(c>>0)&0xf]);
  117 }
  118 
  119 static void
  120 gdb_cnflush(void *arg)
  121 {
  122         struct gdbcons *gc = arg;
  123         int i;
  124 
  125         gdb_tx_begin('O');
  126         for (i = 0; i < gc->npending; i++)
  127                 gdb_tx_puthex(gc->buf[i]);
  128         gdb_tx_end();
  129         gc->npending = 0;
  130 }
  131 
  132 /*
  133  * This glop is to figure out when it's safe to use callouts
  134  * to defer buffer flushing.  There's probably a better way
  135  * and/or an earlier point in the boot process when it's ok.
  136  */
  137 static int calloutok = 0;
  138 static void
  139 oktousecallout(void *data __unused)
  140 {
  141         calloutok = 1;
  142 }
  143 SYSINIT(gdbhack, SI_SUB_LAST, SI_ORDER_MIDDLE, oktousecallout, NULL);
  144 
  145 static void
  146 gdb_cnputc(struct consdev *cp, int c)
  147 {
  148         struct gdbcons *gc;
  149 
  150         if (gdbcons_enable && gdb_cur != NULL && gdb_listening) {
  151                 gc = cp->cn_arg;
  152                 if (gc->npending != 0) {
  153                         /*
  154                          * Cancel any pending callout and flush the
  155                          * buffer if there's no space for this byte.
  156                          */
  157                         if (calloutok)
  158                                 callout_stop(&gc->flush);
  159                         if (gc->npending == sizeof(gc->buf))
  160                                 gdb_cnflush(gc);
  161                 }
  162                 gc->buf[gc->npending++] = c;
  163                 /*
  164                  * Flush on end of line; this is especially helpful
  165                  * during boot when we don't have callouts to flush
  166                  * the buffer.  Otherwise we defer flushing; a 1/4 
  167                  * second is a guess.
  168                  */
  169                 if (c == '\n')
  170                         gdb_cnflush(gc);
  171                 else if (calloutok)
  172                         callout_reset(&gc->flush, hz/4, gdb_cnflush, gc);
  173         }
  174 }
  175 
  176 CONSOLE_DRIVER(gdb);
  177 
  178 /*
  179  * Our console device only gets attached if the system is booted
  180  * with RB_MULTIPLE set so gdb_init also calls us to attach the
  181  * console so we're setup regardless.
  182  */
  183 void
  184 gdb_consinit(void)
  185 {
  186         gdb_cnprobe(&gdb_consdev);
  187         gdb_cninit(&gdb_consdev);
  188         cnadd(&gdb_consdev);
  189 }

Cache object: 7841856f805cd7fbf1a9d564b18cda8e


[ 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.