1 /*- 2 * Copyright (c) 2006 Sam Leffler 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 /* 28 * Support for redirecting console msgs to gdb. We register 29 * a pseudo console to hook cnputc and send stuff to the gdb 30 * port. The only trickiness here is buffering output so this 31 * isn't dog slow. 32 */ 33 34 #include <sys/cdefs.h> 35 __FBSDID("$FreeBSD$"); 36 37 #include <sys/param.h> 38 #include <sys/systm.h> 39 #include <sys/cons.h> 40 #include <sys/kdb.h> 41 #include <sys/kernel.h> 42 #include <sys/malloc.h> 43 #include <sys/reboot.h> 44 #include <sys/sysctl.h> 45 46 #include <machine/gdb_machdep.h> 47 #include <machine/kdb.h> 48 49 #include <gdb/gdb.h> 50 #include <gdb/gdb_int.h> 51 52 struct gdbcons { 53 int npending; 54 /* /2 for hex conversion, -6 for protocol glue */ 55 char buf[GDB_BUFSZ/2 - 6]; 56 struct callout flush; 57 }; 58 static struct gdbcons state = { -1 }; 59 60 static int gdbcons_enable = 0; 61 SYSCTL_INT(_debug, OID_AUTO, gdbcons, CTLFLAG_RW, &gdbcons_enable, 62 0, "copy console messages to gdb"); 63 TUNABLE_INT("debug.gdbcons", &gdbcons_enable); 64 65 static void 66 gdb_cnprobe(struct consdev *cp) 67 { 68 sprintf(cp->cn_name, "gdb"); 69 cp->cn_pri = CN_LOW; /* XXX no way to say "write only" */ 70 } 71 72 static void 73 gdb_cninit(struct consdev *cp) 74 { 75 struct gdbcons *c = &state; 76 77 /* setup tx buffer and callout */ 78 if (c->npending == -1) { 79 c->npending = 0; 80 callout_init(&c->flush, CALLOUT_MPSAFE); 81 cp->cn_arg = c; 82 } 83 } 84 85 static void 86 gdb_cnterm(struct consdev *cp) 87 { 88 } 89 90 static int 91 gdb_cngetc(struct consdev *cp) 92 { 93 return -1; 94 } 95 96 static void 97 gdb_tx_puthex(int c) 98 { 99 const char *hex = "0123456789abcdef"; 100 101 gdb_tx_char(hex[(c>>4)&0xf]); 102 gdb_tx_char(hex[(c>>0)&0xf]); 103 } 104 105 static void 106 gdb_cnflush(void *arg) 107 { 108 struct gdbcons *gc = arg; 109 int i; 110 111 gdb_tx_begin('O'); 112 for (i = 0; i < gc->npending; i++) 113 gdb_tx_puthex(gc->buf[i]); 114 gdb_tx_end(); 115 gc->npending = 0; 116 } 117 118 /* 119 * This glop is to figure out when it's safe to use callouts 120 * to defer buffer flushing. There's probably a better way 121 * and/or an earlier point in the boot process when it's ok. 122 */ 123 static int calloutok = 0; 124 static void 125 oktousecallout(void *data __unused) 126 { 127 calloutok = 1; 128 } 129 SYSINIT(gdbhack, SI_SUB_RUN_SCHEDULER, SI_ORDER_ANY, oktousecallout, NULL) 130 131 static void 132 gdb_cnputc(struct consdev *cp, int c) 133 { 134 struct gdbcons *gc; 135 136 if (gdbcons_enable && gdb_cur != NULL && gdb_listening) { 137 gc = cp->cn_arg; 138 if (gc->npending != 0) { 139 /* 140 * Cancel any pending callout and flush the 141 * buffer if there's no space for this byte. 142 */ 143 if (calloutok) 144 callout_stop(&gc->flush); 145 if (gc->npending == sizeof(gc->buf)) 146 gdb_cnflush(gc); 147 } 148 gc->buf[gc->npending++] = c; 149 /* 150 * Flush on end of line; this is especially helpful 151 * during boot when we don't have callouts to flush 152 * the buffer. Otherwise we defer flushing; a 1/4 153 * second is a guess. 154 */ 155 if (c == '\n') 156 gdb_cnflush(gc); 157 else if (calloutok) 158 callout_reset(&gc->flush, hz/4, gdb_cnflush, gc); 159 } 160 } 161 162 CONSOLE_DRIVER(gdb); 163 164 /* 165 * Our console device only gets attached if the system is booted 166 * with RB_MULTIPLE set so gdb_init also calls us to attach the 167 * console so we're setup regardless. 168 */ 169 void 170 gdb_consinit(void) 171 { 172 gdb_cnprobe(&gdb_consdev); 173 gdb_cninit(&gdb_consdev); 174 cnadd(&gdb_consdev); 175 } 176