sys/gdb/gdb_main.c

   1 /*-
   2  * Copyright (c) 2004 Marcel Moolenaar
   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 <sys/param.h>
  31 #include <sys/systm.h>
  32 #include <sys/kdb.h>
  33 #include <sys/kernel.h>
  34 #include <sys/pcpu.h>
  35 #include <sys/proc.h>
  36 #include <sys/reboot.h>
  37
  38 #include <machine/gdb_machdep.h>
  39 #include <machine/kdb.h>
  40
  41 #include <gdb/gdb.h>
  42 #include <gdb/gdb_int.h>
  43
  44 static dbbe_init_f gdb_init;
  45 static dbbe_trap_f gdb_trap;
  46
  47 KDB_BACKEND(gdb, gdb_init, NULL, NULL, gdb_trap);
  48
  49 static struct gdb_dbgport null_gdb_dbgport;
  50 DATA_SET(gdb_dbgport_set, null_gdb_dbgport);
  51 SET_DECLARE(gdb_dbgport_set, struct gdb_dbgport);
  52
  53 struct gdb_dbgport *gdb_cur = NULL;
  54 int gdb_listening = 0;
  55
  56 static int
  57 gdb_init(void)
  58 {
  59         struct gdb_dbgport *dp, **iter;
  60         int cur_pri, pri;
  61
  62         gdb_cur = NULL;
  63         cur_pri = -1;
  64         SET_FOREACH(iter, gdb_dbgport_set) {
  65                 dp = *iter;
  66                 pri = (dp->gdb_probe != NULL) ? dp->gdb_probe() : -1;
  67                 dp->gdb_active = (pri >= 0) ? 0 : -1;
  68                 if (pri > cur_pri) {
  69                         cur_pri = pri;
  70                         gdb_cur = dp;
  71                 }
  72         }
  73         if (gdb_cur != NULL) {
  74                 printf("GDB: debug ports:");
  75                 SET_FOREACH(iter, gdb_dbgport_set) {
  76                         dp = *iter;
  77                         if (dp->gdb_active == 0)
  78                                 printf(" %s", dp->gdb_name);
  79                 }
  80                 printf("\n");
  81         } else
  82                 printf("GDB: no debug ports present\n");
  83         if (gdb_cur != NULL) {
  84                 gdb_cur->gdb_init();
  85                 printf("GDB: current port: %s\n", gdb_cur->gdb_name);
  86         }
  87         if (gdb_cur != NULL) {
  88                 cur_pri = (boothowto & RB_GDB) ? 2 : 0;
  89                 gdb_consinit();
  90         } else
  91                 cur_pri = -1;
  92         return (cur_pri);
  93 }
  94
  95 static int
  96 gdb_trap(int type, int code)
  97 {
  98         jmp_buf jb;
  99         struct thread *thr_iter;
 100         void *prev_jb;
 101
 102         prev_jb = kdb_jmpbuf(jb);
 103         if (setjmp(jb) != 0) {
 104                 printf("%s bailing, hopefully back to ddb!\n", __func__);
 105                 gdb_listening = 0;
 106                 (void)kdb_jmpbuf(prev_jb);
 107                 return (1);
 108         }
 109
 110         gdb_listening = 0;
 111         /*
 112          * Send a T packet. We currently do not support watchpoints (the
 113          * awatch, rwatch or watch elements).
 114          */
 115         gdb_tx_begin('T');
 116         gdb_tx_hex(gdb_cpu_signal(type, code), 2);
 117         gdb_tx_varhex(GDB_REG_PC);
 118         gdb_tx_char(':');
 119         gdb_tx_reg(GDB_REG_PC);
 120         gdb_tx_char(';');
 121         gdb_tx_str("thread:");
 122         gdb_tx_varhex((long)kdb_thread->td_tid);
 123         gdb_tx_char(';');
 124         gdb_tx_end();                   /* XXX check error condition. */
 125
 126         thr_iter = NULL;
 127         while (gdb_rx_begin() == 0) {
 128                 /* printf("GDB: got '%s'\n", gdb_rxp); */
 129                 switch (gdb_rx_char()) {
 130                 case '?':       /* Last signal. */
 131                         gdb_tx_begin('S');
 132                         gdb_tx_hex(gdb_cpu_signal(type, code), 2);
 133                         gdb_tx_end();
 134                         break;
 135                 case 'c': {     /* Continue. */
 136                         uintmax_t addr;
 137                         register_t pc;
 138                         if (!gdb_rx_varhex(&addr)) {
 139                                 pc = addr;
 140                                 gdb_cpu_setreg(GDB_REG_PC, &pc);
 141                         }
 142                         kdb_cpu_clear_singlestep();
 143                         gdb_listening = 1;
 144                         return (1);
 145                 }
 146                 case 'C': {     /* Continue with signal. */
 147                         uintmax_t addr, sig;
 148                         register_t pc;
 149                         if (!gdb_rx_varhex(&sig) && gdb_rx_char() == ';' &&
 150                             !gdb_rx_varhex(&addr)) {
 151                                 pc = addr;
 152                                 gdb_cpu_setreg(GDB_REG_PC, &pc);
 153                         }
 154                         kdb_cpu_clear_singlestep();
 155                         gdb_listening = 1;
 156                         return (1);
 157                 }
 158                 case 'D': {     /* Detach */
 159                         gdb_tx_ok();
 160                         kdb_cpu_clear_singlestep();
 161                         return (1);
 162                 }
 163                 case 'g': {     /* Read registers. */
 164                         size_t r;
 165                         gdb_tx_begin(0);
 166                         for (r = 0; r < GDB_NREGS; r++)
 167                                 gdb_tx_reg(r);
 168                         gdb_tx_end();
 169                         break;
 170                 }
 171                 case 'G':       /* Write registers. */
 172                         gdb_tx_err(0);
 173                         break;
 174                 case 'H': {     /* Set thread. */
 175                         intmax_t tid;
 176                         struct thread *thr;
 177                         gdb_rx_char();
 178                         if (gdb_rx_varhex(&tid)) {
 179                                 gdb_tx_err(EINVAL);
 180                                 break;
 181                         }
 182                         if (tid > 0) {
 183                                 thr = kdb_thr_lookup(tid);
 184                                 if (thr == NULL) {
 185                                         gdb_tx_err(ENOENT);
 186                                         break;
 187                                 }
 188                                 kdb_thr_select(thr);
 189                         }
 190                         gdb_tx_ok();
 191                         break;
 192                 }
 193                 case 'k':       /* Kill request. */
 194                         kdb_cpu_clear_singlestep();
 195                         gdb_listening = 1;
 196                         return (1);
 197                 case 'm': {     /* Read memory. */
 198                         uintmax_t addr, size;
 199                         if (gdb_rx_varhex(&addr) || gdb_rx_char() != ',' ||
 200                             gdb_rx_varhex(&size)) {
 201                                 gdb_tx_err(EINVAL);
 202                                 break;
 203                         }
 204                         gdb_tx_begin(0);
 205                         if (gdb_tx_mem((char *)(uintptr_t)addr, size))
 206                                 gdb_tx_end();
 207                         else
 208                                 gdb_tx_err(EIO);
 209                         break;
 210                 }
 211                 case 'M': {     /* Write memory. */
 212                         uintmax_t addr, size;
 213                         if (gdb_rx_varhex(&addr) || gdb_rx_char() != ',' ||
 214                             gdb_rx_varhex(&size) || gdb_rx_char() != ':') {
 215                                 gdb_tx_err(EINVAL);
 216                                 break;
 217                         }
 218                         if (gdb_rx_mem((char *)(uintptr_t)addr, size) == 0)
 219                                 gdb_tx_err(EIO);
 220                         else
 221                                 gdb_tx_ok();
 222                         break;
 223                 }
 224                 case 'P': {     /* Write register. */
 225                         char *val;
 226                         uintmax_t reg;
 227                         val = gdb_rxp;
 228                         if (gdb_rx_varhex(&reg) || gdb_rx_char() != '=' ||
 229                             !gdb_rx_mem(val, gdb_cpu_regsz(reg))) {
 230                                 gdb_tx_err(EINVAL);
 231                                 break;
 232                         }
 233                         gdb_cpu_setreg(reg, val);
 234                         gdb_tx_ok();
 235                         break;
 236                 }
 237                 case 'q':       /* General query. */
 238                         if (gdb_rx_equal("fThreadInfo")) {
 239                                 thr_iter = kdb_thr_first();
 240                                 gdb_tx_begin('m');
 241                                 gdb_tx_hex((long)thr_iter->td_tid, 8);
 242                                 gdb_tx_end();
 243                         } else if (gdb_rx_equal("sThreadInfo")) {
 244                                 if (thr_iter == NULL) {
 245                                         gdb_tx_err(ENXIO);
 246                                         break;
 247                                 }
 248                                 thr_iter = kdb_thr_next(thr_iter);
 249                                 if (thr_iter != NULL) {
 250                                         gdb_tx_begin('m');
 251                                         gdb_tx_hex((long)thr_iter->td_tid, 8);
 252                                         gdb_tx_end();
 253                                 } else {
 254                                         gdb_tx_begin('l');
 255                                         gdb_tx_end();
 256                                 }
 257                         } else if (!gdb_cpu_query())
 258                                 gdb_tx_empty();
 259                         break;
 260                 case 's': {     /* Step. */
 261                         uintmax_t addr;
 262                         register_t pc;
 263                         if (!gdb_rx_varhex(&addr)) {
 264                                 pc = addr;
 265                                 gdb_cpu_setreg(GDB_REG_PC, &pc);
 266                         }
 267                         kdb_cpu_set_singlestep();
 268                         gdb_listening = 1;
 269                         return (1);
 270                 }
 271                 case 'S': {     /* Step with signal. */
 272                         uintmax_t addr, sig;
 273                         register_t pc;
 274                         if (!gdb_rx_varhex(&sig) && gdb_rx_char() == ';' &&
 275                             !gdb_rx_varhex(&addr)) {
 276                                 pc = addr;
 277                                 gdb_cpu_setreg(GDB_REG_PC, &pc);
 278                         }
 279                         kdb_cpu_set_singlestep();
 280                         gdb_listening = 1;
 281                         return (1);
 282                 }
 283                 case 'T': {     /* Thread alive. */
 284                         intmax_t tid;
 285                         if (gdb_rx_varhex(&tid)) {
 286                                 gdb_tx_err(EINVAL);
 287                                 break;
 288                         }
 289                         if (kdb_thr_lookup(tid) != NULL)
 290                                 gdb_tx_ok();
 291                         else
 292                                 gdb_tx_err(ENOENT);
 293                         break;
 294                 }
 295                 case -1:
 296                         /* Empty command. Treat as unknown command. */
 297                         /* FALLTHROUGH */
 298                 default:
 299                         /* Unknown command. Send empty response. */
 300                         gdb_tx_empty();
 301                         break;
 302                 }
 303         }
 304         (void)kdb_jmpbuf(prev_jb);
 305         return (0);
 306 }