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