sys/gdb/gdb_main.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
   3  *
   4  * Copyright (c) 2004 Marcel Moolenaar
   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 #include <sys/cdefs.h>
  30 __FBSDID("$FreeBSD$");
  31
  32 #include <sys/param.h>
  33 #include <sys/systm.h>
  34 #include <sys/kdb.h>
  35 #include <sys/kernel.h>
  36 #include <sys/pcpu.h>
  37 #include <sys/proc.h>
  38 #include <sys/reboot.h>
  39
  40 #include <machine/gdb_machdep.h>
  41 #include <machine/kdb.h>
  42
  43 #include <gdb/gdb.h>
  44 #include <gdb/gdb_int.h>
  45
  46 static dbbe_init_f gdb_init;
  47 static dbbe_trap_f gdb_trap;
  48
  49 KDB_BACKEND(gdb, gdb_init, NULL, NULL, gdb_trap);
  50
  51 static struct gdb_dbgport null_gdb_dbgport;
  52 DATA_SET(gdb_dbgport_set, null_gdb_dbgport);
  53 SET_DECLARE(gdb_dbgport_set, struct gdb_dbgport);
  54
  55 struct gdb_dbgport *gdb_cur = NULL;
  56 int gdb_listening = 0;
  57
  58 static unsigned char gdb_bindata[64];
  59
  60 static int
  61 gdb_init(void)
  62 {
  63         struct gdb_dbgport *dp, **iter;
  64         int cur_pri, pri;
  65
  66         gdb_cur = NULL;
  67         cur_pri = -1;
  68         SET_FOREACH(iter, gdb_dbgport_set) {
  69                 dp = *iter;
  70                 pri = (dp->gdb_probe != NULL) ? dp->gdb_probe() : -1;
  71                 dp->gdb_active = (pri >= 0) ? 0 : -1;
  72                 if (pri > cur_pri) {
  73                         cur_pri = pri;
  74                         gdb_cur = dp;
  75                 }
  76         }
  77         if (gdb_cur != NULL) {
  78                 printf("GDB: debug ports:");
  79                 SET_FOREACH(iter, gdb_dbgport_set) {
  80                         dp = *iter;
  81                         if (dp->gdb_active == 0)
  82                                 printf(" %s", dp->gdb_name);
  83                 }
  84                 printf("\n");
  85         } else
  86                 printf("GDB: no debug ports present\n");
  87         if (gdb_cur != NULL) {
  88                 gdb_cur->gdb_init();
  89                 printf("GDB: current port: %s\n", gdb_cur->gdb_name);
  90         }
  91         if (gdb_cur != NULL) {
  92                 cur_pri = (boothowto & RB_GDB) ? 2 : 0;
  93                 gdb_consinit();
  94         } else
  95                 cur_pri = -1;
  96         return (cur_pri);
  97 }
  98
  99 static void
 100 gdb_do_mem_search(void)
 101 {
 102         size_t patlen;
 103         intmax_t addr, size;
 104         const unsigned char *found;
 105
 106         if (gdb_rx_varhex(&addr) || gdb_rx_char() != ';' ||
 107             gdb_rx_varhex(&size) || gdb_rx_char() != ';' ||
 108             gdb_rx_bindata(gdb_bindata, sizeof(gdb_bindata), &patlen)) {
 109                 gdb_tx_err(EINVAL);
 110                 return;
 111         }
 112         if (gdb_search_mem((char *)(uintptr_t)addr, size, gdb_bindata,
 113             patlen, &found)) {
 114                 if (found == 0ULL)
 115                         gdb_tx_begin('0');
 116                 else {
 117                         gdb_tx_begin('1');
 118                         gdb_tx_char(',');
 119                         gdb_tx_hex((intmax_t)(uintptr_t)found, 8);
 120                 }
 121                 gdb_tx_end();
 122         } else
 123                 gdb_tx_err(EIO);
 124 }
 125
 126 static int
 127 gdb_trap(int type, int code)
 128 {
 129         jmp_buf jb;
 130         struct thread *thr_iter;
 131         void *prev_jb;
 132
 133         prev_jb = kdb_jmpbuf(jb);
 134         if (setjmp(jb) != 0) {
 135                 printf("%s bailing, hopefully back to ddb!\n", __func__);
 136                 gdb_listening = 0;
 137                 (void)kdb_jmpbuf(prev_jb);
 138                 return (1);
 139         }
 140
 141         gdb_listening = 0;
 142         /*
 143          * Send a T packet. We currently do not support watchpoints (the
 144          * awatch, rwatch or watch elements).
 145          */
 146         gdb_tx_begin('T');
 147         gdb_tx_hex(gdb_cpu_signal(type, code), 2);
 148         gdb_tx_varhex(GDB_REG_PC);
 149         gdb_tx_char(':');
 150         gdb_tx_reg(GDB_REG_PC);
 151         gdb_tx_char(';');
 152         gdb_tx_str("thread:");
 153         gdb_tx_varhex((long)kdb_thread->td_tid);
 154         gdb_tx_char(';');
 155         gdb_tx_end();                   /* XXX check error condition. */
 156
 157         thr_iter = NULL;
 158         while (gdb_rx_begin() == 0) {
 159                 /* printf("GDB: got '%s'\n", gdb_rxp); */
 160                 switch (gdb_rx_char()) {
 161                 case '?':       /* Last signal. */
 162                         gdb_tx_begin('S');
 163                         gdb_tx_hex(gdb_cpu_signal(type, code), 2);
 164                         gdb_tx_end();
 165                         break;
 166                 case 'c': {     /* Continue. */
 167                         uintmax_t addr;
 168                         register_t pc;
 169                         if (!gdb_rx_varhex(&addr)) {
 170                                 pc = addr;
 171                                 gdb_cpu_setreg(GDB_REG_PC, &pc);
 172                         }
 173                         kdb_cpu_clear_singlestep();
 174                         gdb_listening = 1;
 175                         return (1);
 176                 }
 177                 case 'C': {     /* Continue with signal. */
 178                         uintmax_t addr, sig;
 179                         register_t pc;
 180                         if (!gdb_rx_varhex(&sig) && gdb_rx_char() == ';' &&
 181                             !gdb_rx_varhex(&addr)) {
 182                                 pc = addr;
 183                                 gdb_cpu_setreg(GDB_REG_PC, &pc);
 184                         }
 185                         kdb_cpu_clear_singlestep();
 186                         gdb_listening = 1;
 187                         return (1);
 188                 }
 189                 case 'D': {     /* Detach */
 190                         gdb_tx_ok();
 191                         kdb_cpu_clear_singlestep();
 192                         return (1);
 193                 }
 194                 case 'g': {     /* Read registers. */
 195                         size_t r;
 196                         gdb_tx_begin(0);
 197                         for (r = 0; r < GDB_NREGS; r++)
 198                                 gdb_tx_reg(r);
 199                         gdb_tx_end();
 200                         break;
 201                 }
 202                 case 'G':       /* Write registers. */
 203                         gdb_tx_err(0);
 204                         break;
 205                 case 'H': {     /* Set thread. */
 206                         intmax_t tid;
 207                         struct thread *thr;
 208                         gdb_rx_char();
 209                         if (gdb_rx_varhex(&tid)) {
 210                                 gdb_tx_err(EINVAL);
 211                                 break;
 212                         }
 213                         if (tid > 0) {
 214                                 thr = kdb_thr_lookup(tid);
 215                                 if (thr == NULL) {
 216                                         gdb_tx_err(ENOENT);
 217                                         break;
 218                                 }
 219                                 kdb_thr_select(thr);
 220                         }
 221                         gdb_tx_ok();
 222                         break;
 223                 }
 224                 case 'k':       /* Kill request. */
 225                         kdb_cpu_clear_singlestep();
 226                         gdb_listening = 1;
 227                         return (1);
 228                 case 'm': {     /* Read memory. */
 229                         uintmax_t addr, size;
 230                         if (gdb_rx_varhex(&addr) || gdb_rx_char() != ',' ||
 231                             gdb_rx_varhex(&size)) {
 232                                 gdb_tx_err(EINVAL);
 233                                 break;
 234                         }
 235                         gdb_tx_begin(0);
 236                         if (gdb_tx_mem((char *)(uintptr_t)addr, size))
 237                                 gdb_tx_end();
 238                         else
 239                                 gdb_tx_err(EIO);
 240                         break;
 241                 }
 242                 case 'M': {     /* Write memory. */
 243                         uintmax_t addr, size;
 244                         if (gdb_rx_varhex(&addr) || gdb_rx_char() != ',' ||
 245                             gdb_rx_varhex(&size) || gdb_rx_char() != ':') {
 246                                 gdb_tx_err(EINVAL);
 247                                 break;
 248                         }
 249                         if (gdb_rx_mem((char *)(uintptr_t)addr, size) == 0)
 250                                 gdb_tx_err(EIO);
 251                         else
 252                                 gdb_tx_ok();
 253                         break;
 254                 }
 255                 case 'P': {     /* Write register. */
 256                         char *val;
 257                         uintmax_t reg;
 258                         val = gdb_rxp;
 259                         if (gdb_rx_varhex(&reg) || gdb_rx_char() != '=' ||
 260                             !gdb_rx_mem(val, gdb_cpu_regsz(reg))) {
 261                                 gdb_tx_err(EINVAL);
 262                                 break;
 263                         }
 264                         gdb_cpu_setreg(reg, val);
 265                         gdb_tx_ok();
 266                         break;
 267                 }
 268                 case 'q':       /* General query. */
 269                         if (gdb_rx_equal("fThreadInfo")) {
 270                                 thr_iter = kdb_thr_first();
 271                                 gdb_tx_begin('m');
 272                                 gdb_tx_hex((long)thr_iter->td_tid, 8);
 273                                 gdb_tx_end();
 274                         } else if (gdb_rx_equal("sThreadInfo")) {
 275                                 if (thr_iter == NULL) {
 276                                         gdb_tx_err(ENXIO);
 277                                         break;
 278                                 }
 279                                 thr_iter = kdb_thr_next(thr_iter);
 280                                 if (thr_iter != NULL) {
 281                                         gdb_tx_begin('m');
 282                                         gdb_tx_hex((long)thr_iter->td_tid, 8);
 283                                         gdb_tx_end();
 284                                 } else {
 285                                         gdb_tx_begin('l');
 286                                         gdb_tx_end();
 287                                 }
 288                         } else if (gdb_rx_equal("Search:memory:")) {
 289                                 gdb_do_mem_search();
 290                         } else if (!gdb_cpu_query())
 291                                 gdb_tx_empty();
 292                         break;
 293                 case 's': {     /* Step. */
 294                         uintmax_t addr;
 295                         register_t pc;
 296                         if (!gdb_rx_varhex(&addr)) {
 297                                 pc = addr;
 298                                 gdb_cpu_setreg(GDB_REG_PC, &pc);
 299                         }
 300                         kdb_cpu_set_singlestep();
 301                         gdb_listening = 1;
 302                         return (1);
 303                 }
 304                 case 'S': {     /* Step with signal. */
 305                         uintmax_t addr, sig;
 306                         register_t pc;
 307                         if (!gdb_rx_varhex(&sig) && gdb_rx_char() == ';' &&
 308                             !gdb_rx_varhex(&addr)) {
 309                                 pc = addr;
 310                                 gdb_cpu_setreg(GDB_REG_PC, &pc);
 311                         }
 312                         kdb_cpu_set_singlestep();
 313                         gdb_listening = 1;
 314                         return (1);
 315                 }
 316                 case 'T': {     /* Thread alive. */
 317                         intmax_t tid;
 318                         if (gdb_rx_varhex(&tid)) {
 319                                 gdb_tx_err(EINVAL);
 320                                 break;
 321                         }
 322                         if (kdb_thr_lookup(tid) != NULL)
 323                                 gdb_tx_ok();
 324                         else
 325                                 gdb_tx_err(ENOENT);
 326                         break;
 327                 }
 328                 case -1:
 329                         /* Empty command. Treat as unknown command. */
 330                         /* FALLTHROUGH */
 331                 default:
 332                         /* Unknown command. Send empty response. */
 333                         gdb_tx_empty();
 334                         break;
 335                 }
 336         }
 337         (void)kdb_jmpbuf(prev_jb);
 338         return (0);
 339 }