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