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   1 /*
   2         sim_gdb.c
   3
   4         Copyright 2008, 2009 Michel Pollet <buserror@gmail.com>
   5
   6         This file is part of simavr.
   7
   8         simavr is free software: you can redistribute it and/or modify
   9         it under the terms of the GNU General Public License as published by
  10         the Free Software Foundation, either version 3 of the License, or
  11         (at your option) any later version.
  12
  13         simavr is distributed in the hope that it will be useful,
  14         but WITHOUT ANY WARRANTY; without even the implied warranty of
  15         MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16         GNU General Public License for more details.
  17
  18         You should have received a copy of the GNU General Public License
  19         along with simavr.  If not, see <http://www.gnu.org/licenses/>.
  20  */
  21
  22 #include <netinet/in.h>
  23 #include <netinet/tcp.h>
  24 #include <arpa/inet.h>
  25 #include <sys/socket.h>
  26 #include <sys/time.h>
  27 #include <stdlib.h>
  28 #include <stdio.h>
  29 #include <unistd.h>
  30 #include <string.h>
  31 #include <errno.h>
  32 #include <poll.h>
  33 #include <pthread.h>
  34 #include "sim_avr.h"
  35 #include "sim_hex.h"
  36 #include "avr_eeprom.h"
  37 #include "sim_gdb.h"
  38
  39 #define DBG(w)
  40
  41 #define WATCH_LIMIT (32)
  42
  43 typedef struct {
  44         uint32_t len; /**< How many points are taken (points[0] .. points[len - 1]). */
  45         struct {
  46                 uint32_t addr; /**< Which address is watched. */
  47                 uint32_t size; /**< How large is the watched segment. */
  48                 uint32_t kind; /**< Bitmask of enum avr_gdb_watch_type values. */
  49         } points[WATCH_LIMIT];
  50 } avr_gdb_watchpoints_t;
  51
  52 typedef struct avr_gdb_t {
  53         avr_t * avr;
  54         int             listen; // listen socket
  55         int             s;              // current gdb connection
  56
  57         avr_gdb_watchpoints_t breakpoints;
  58         avr_gdb_watchpoints_t watchpoints;
  59 } avr_gdb_t;
  60
  61
  62 /**
  63  * Returns the index of the watchpoint if found, -1 otherwise.
  64  */
  65 static int gdb_watch_find(const avr_gdb_watchpoints_t * w, uint32_t addr)
  66 {
  67         for (int i = 0; i < w->len; i++) {
  68                 if (w->points[i].addr > addr) {
  69                         return -1;
  70                 } else if (w->points[i].addr == addr) {
  71                         return i;
  72                 }
  73         }
  74
  75         return -1;
  76 }
  77
  78 /**
  79  * Contrary to gdb_watch_find, this actually checks the address against
  80  * a watched memory _range_.
  81  */
  82 static int gdb_watch_find_range(const avr_gdb_watchpoints_t * w, uint32_t addr)
  83 {
  84         for (int i = 0; i < w->len; i++) {
  85                 if (w->points[i].addr > addr) {
  86                         return -1;
  87                 } else if (w->points[i].addr <= addr && addr < w->points[i].addr + w->points[i].size) {
  88                         return i;
  89                 }
  90         }
  91
  92         return -1;
  93 }
  94
  95 /**
  96  * Returns -1 on error, 0 otherwise.
  97  */
  98 static int gdb_watch_add_or_update(avr_gdb_watchpoints_t * w, enum avr_gdb_watch_type kind, uint32_t addr,
  99                 uint32_t size)
 100 {
 101         /* If the watchpoint exists, update it. */
 102         int i = gdb_watch_find(w, addr);
 103         if (i != -1) {
 104                 w->points[i].size = size;
 105                 w->points[i].kind |= kind;
 106                 return 0;
 107         }
 108
 109         /* Otherwise add it. */
 110         if (w->len == WATCH_LIMIT) {
 111                 return -1;
 112         }
 113
 114         /* Find the insertion point. */
 115         for (i = 0; i < w->len; i++) {
 116                 if (w->points[i].addr > addr) {
 117                         break;
 118                 }
 119         }
 120
 121         w->len++;
 122
 123         /* Make space for new element. */
 124         for (int j = i + 1; j < w->len; j++) {
 125                 w->points[j] = w->points[j - 1];
 126         }
 127
 128         /* Insert it. */
 129         w->points[i].kind = kind;
 130         w->points[i].addr = addr;
 131         w->points[i].size = size;
 132
 133         return 0;
 134 }
 135
 136 /**
 137  * Returns -1 on error or if the specified point does not exist, 0 otherwise.
 138  */
 139 static int gdb_watch_rm(avr_gdb_watchpoints_t * w, enum avr_gdb_watch_type kind, uint32_t addr)
 140 {
 141         int i = gdb_watch_find(w, addr);
 142         if (i == -1) {
 143                 return -1;
 144         }
 145
 146         w->points[i].kind &= ~kind;
 147         if (w->points[i].kind) {
 148                 return 0;
 149         }
 150
 151         for (i = i + 1; i < w->len; i++) {
 152                 w->points[i - 1] = w->points[i];
 153         }
 154
 155         w->len--;
 156
 157         return 0;
 158 }
 159
 160 static void gdb_watch_clear(avr_gdb_watchpoints_t * w)
 161 {
 162         w->len = 0;
 163 }
 164
 165 static void gdb_send_reply(avr_gdb_t * g, char * cmd)
 166 {
 167         uint8_t reply[1024];
 168         uint8_t * dst = reply;
 169         uint8_t check = 0;
 170         *dst++ = '$';
 171         while (*cmd) {
 172                 check += *cmd;
 173                 *dst++ = *cmd++;
 174         }
 175         sprintf((char*)dst, "#%02x", check);
 176         DBG(printf("%s '%s'\n", __FUNCTION__, reply);)
 177         send(g->s, reply, dst - reply + 3, 0);
 178 }
 179
 180 static void gdb_send_quick_status(avr_gdb_t * g, uint8_t signal)
 181 {
 182         char cmd[64];
 183
 184         sprintf(cmd, "T%02x20:%02x;21:%02x%02x;22:%02x%02x%02x00;",
 185                 signal ? signal : 5, g->avr->data[R_SREG],
 186                 g->avr->data[R_SPL], g->avr->data[R_SPH],
 187                 g->avr->pc & 0xff, (g->avr->pc>>8)&0xff, (g->avr->pc>>16)&0xff);
 188         gdb_send_reply(g, cmd);
 189 }
 190
 191 static int gdb_change_breakpoint(avr_gdb_watchpoints_t * w, int set, enum avr_gdb_watch_type kind,
 192                 uint32_t addr, uint32_t size)
 193 {
 194         DBG(printf("set %d kind %d addr %08x len %d\n", set, kind, addr, len);)
 195
 196         if (set) {
 197                 return gdb_watch_add_or_update(w, kind, addr, size);
 198         } else {
 199                 return gdb_watch_rm(w, kind, addr);
 200         }
 201
 202         return -1;
 203 }
 204
 205 static int gdb_write_register(avr_gdb_t * g, int regi, uint8_t * src)
 206 {
 207         switch (regi) {
 208                 case 0 ... 31:
 209                         g->avr->data[regi] = *src;
 210                         return 1;
 211                 case 32:
 212                         g->avr->data[R_SREG] = *src;
 213                         return 1;
 214                 case 33:
 215                         g->avr->data[R_SPL] = src[0];
 216                         g->avr->data[R_SPH] = src[1];
 217                         return 2;
 218                 case 34:
 219                         g->avr->pc = src[0] | (src[1] << 8) | (src[2] << 16) | (src[3] << 24);
 220                         return 4;
 221         }
 222         return 1;
 223 }
 224
 225 static int gdb_read_register(avr_gdb_t * g, int regi, char * rep)
 226 {
 227         switch (regi) {
 228                 case 0 ... 31:
 229                         sprintf(rep, "%02x", g->avr->data[regi]);
 230                         break;
 231                 case 32:
 232                         sprintf(rep, "%02x", g->avr->data[R_SREG]);
 233                         break;
 234                 case 33:
 235                         sprintf(rep, "%02x%02x", g->avr->data[R_SPL], g->avr->data[R_SPH]);
 236                         break;
 237                 case 34:
 238                         sprintf(rep, "%02x%02x%02x00",
 239                                 g->avr->pc & 0xff, (g->avr->pc>>8)&0xff, (g->avr->pc>>16)&0xff);
 240                         break;
 241         }
 242         return strlen(rep);
 243 }
 244
 245 static void gdb_handle_command(avr_gdb_t * g, char * cmd)
 246 {
 247         avr_t * avr = g->avr;
 248         char rep[1024];
 249         uint8_t command = *cmd++;
 250         switch (command) {
 251                 case '?':
 252                         gdb_send_quick_status(g, 0);
 253                         break;
 254                 case 'G': {     // set all general purpose registers
 255                         // get their binary form
 256                         read_hex_string(cmd, (uint8_t*)rep, strlen(cmd));
 257                         uint8_t *src = (uint8_t*)rep;
 258                         for (int i = 0; i < 35; i++)
 259                                 src += gdb_write_register(g, i, src);
 260                         gdb_send_reply(g, "OK");
 261                 }       break;
 262                 case 'g': {     // read all general purpose registers
 263                         char * dst = rep;
 264                         for (int i = 0; i < 35; i++)
 265                                 dst += gdb_read_register(g, i, dst);
 266                         gdb_send_reply(g, rep);
 267                 }       break;
 268                 case 'p': {     // read register
 269                         unsigned int regi = 0;
 270                         sscanf(cmd, "%x", &regi);
 271                         gdb_read_register(g, regi, rep);
 272                         gdb_send_reply(g, rep);
 273                 }       break;
 274                 case 'P': {     // write register
 275                         unsigned int regi = 0;
 276                         char * val = strchr(cmd, '=');
 277                         if (!val)
 278                                 break;
 279                         *val++ = 0;
 280                         sscanf(cmd, "%x", &regi);
 281                         read_hex_string(val, (uint8_t*)rep, strlen(val));
 282                         gdb_write_register(g, regi, (uint8_t*)rep);
 283                         gdb_send_reply(g, "OK");
 284                 }       break;
 285                 case 'm': {     // read memory
 286                         avr_flashaddr_t addr;
 287                         uint32_t len;
 288                         sscanf(cmd, "%x,%x", &addr, &len);
 289                         uint8_t * src = NULL;
 290                         if (addr < avr->flashend) {
 291                                 src = avr->flash + addr;
 292                         } else if (addr >= 0x800000 && (addr - 0x800000) <= avr->ramend) {
 293                                 src = avr->data + addr - 0x800000;
 294                         } else if (addr >= 0x810000 && (addr - 0x810000) <= avr->e2end) {
 295                                 avr_eeprom_desc_t ee = {.offset = (addr - 0x810000)};
 296                                 avr_ioctl(avr, AVR_IOCTL_EEPROM_GET, &ee);
 297                                 if (ee.ee)
 298                                         src = ee.ee;
 299                                 else {
 300                                         gdb_send_reply(g, "E01");
 301                                         break;
 302                                 }
 303                         } else if (addr >= 0x800000 && (addr - 0x800000) == avr->ramend+1 && len == 2) {
 304                                 // Allow GDB to read a value just after end of stack.
 305                                 // This is necessary to make instruction stepping work when stack is empty
 306                                 printf("GDB read just past end of stack %08x, %08x; returning zero\n", addr, len);
 307                                 gdb_send_reply(g, "0000");
 308                                 break;
 309                         } else {
 310                                 printf("read memory error %08x, %08x (ramend %04x)\n", addr, len, avr->ramend+1);
 311                                 gdb_send_reply(g, "E01");
 312                                 break;
 313                         }
 314                         char * dst = rep;
 315                         while (len--) {
 316                                 sprintf(dst, "%02x", *src++);
 317                                 dst += 2;
 318                         }
 319                         *dst = 0;
 320                         gdb_send_reply(g, rep);
 321                 }       break;
 322                 case 'M': {     // write memory
 323                         uint32_t addr, len;
 324                         sscanf(cmd, "%x,%x", &addr, &len);
 325                         char * start = strchr(cmd, ':');
 326                         if (!start) {
 327                                 gdb_send_reply(g, "E01");
 328                                 break;
 329                         }
 330                         if (addr < 0xffff) {
 331                                 read_hex_string(start + 1, avr->flash + addr, strlen(start+1));
 332                                 gdb_send_reply(g, "OK");
 333                         } else if (addr >= 0x800000 && (addr - 0x800000) <= avr->ramend) {
 334                                 read_hex_string(start + 1, avr->data + addr - 0x800000, strlen(start+1));
 335                                 gdb_send_reply(g, "OK");
 336                         } else if (addr >= 0x810000 && (addr - 0x810000) <= avr->e2end) {
 337                                 read_hex_string(start + 1, (uint8_t*)rep, strlen(start+1));
 338                                 avr_eeprom_desc_t ee = {.offset = (addr - 0x810000), .size = len, .ee = (uint8_t*)rep };
 339                                 avr_ioctl(avr, AVR_IOCTL_EEPROM_SET, &ee);
 340                                 gdb_send_reply(g, "OK");
 341                         } else {
 342                                 printf("write memory error %08x, %08x\n", addr, len);
 343                                 gdb_send_reply(g, "E01");
 344                         }
 345                 }       break;
 346                 case 'c': {     // continue
 347                         avr->state = cpu_Running;
 348                 }       break;
 349                 case 's': {     // step
 350                         avr->state = cpu_Step;
 351                 }       break;
 352                 case 'r': {     // deprecated, suggested for AVRStudio compatibility
 353                         avr->state = cpu_StepDone;
 354                         avr_reset(avr);
 355                 }       break;
 356                 case 'Z':       // set clear break/watchpoint
 357                 case 'z': {
 358                         uint32_t kind, addr, len;
 359                         int set = (command == 'Z');
 360                         sscanf(cmd, "%d,%x,%x", &kind, &addr, &len);
 361 //                      printf("breakpoint %d, %08x, %08x\n", kind, addr, len);
 362                         switch (kind) {
 363                                 case 0: // software breakpoint
 364                                 case 1: // hardware breakpoint
 365                                         if (addr > avr->flashend ||
 366                                                         gdb_change_breakpoint(&g->breakpoints, set, 1 << kind, addr, len) == -1) {
 367                                                 gdb_send_reply(g, "E01");
 368                                                 break;
 369                                         }
 370
 371                                         gdb_send_reply(g, "OK");
 372                                         break;
 373                                 case 2: // write watchpoint
 374                                 case 3: // read watchpoint
 375                                 case 4: // access watchpoint
 376                                         /* Mask out the offset applied to SRAM addresses. */
 377                                         addr &= ~0x800000;
 378                                         if (addr > avr->ramend ||
 379                                                         gdb_change_breakpoint(&g->watchpoints, set, 1 << kind, addr, len) == -1) {
 380                                                 gdb_send_reply(g, "E01");
 381                                                 break;
 382                                         }
 383
 384                                         gdb_send_reply(g, "OK");
 385                                         break;
 386                                 default:
 387                                         gdb_send_reply(g, "");
 388                                         break;
 389                         }
 390                 }       break;
 391                 default:
 392                         gdb_send_reply(g, "");
 393                         break;
 394         }
 395 }
 396
 397 static int gdb_network_handler(avr_gdb_t * g, uint32_t dosleep)
 398 {
 399         fd_set read_set;
 400         int max;
 401         FD_ZERO(&read_set);
 402
 403         if (g->s != -1) {
 404                 FD_SET(g->s, &read_set);
 405                 max = g->s + 1;
 406         } else {
 407                 FD_SET(g->listen, &read_set);
 408                 max = g->listen + 1;
 409         }
 410         struct timeval timo = { 0, dosleep };   // short, but not too short interval
 411         int ret = select(max, &read_set, NULL, NULL, &timo);
 412
 413         if (ret == 0)
 414                 return 0;
 415
 416         if (FD_ISSET(g->listen, &read_set)) {
 417                 g->s = accept(g->listen, NULL, NULL);
 418
 419                 if (g->s == -1) {
 420                         perror("gdb_network_handler accept");
 421                         sleep(5);
 422                         return 1;
 423                 }
 424         int i = 1;
 425         setsockopt (g->s, IPPROTO_TCP, TCP_NODELAY, &i, sizeof (i));
 426                 g->avr->state = cpu_Stopped;
 427                 printf("%s connection opened\n", __FUNCTION__);
 428         }
 429
 430         if (g->s != -1 && FD_ISSET(g->s, &read_set)) {
 431                 uint8_t buffer[1024];
 432
 433                 ssize_t r = recv(g->s, buffer, sizeof(buffer)-1, 0);
 434
 435                 if (r == 0) {
 436                         printf("%s connection closed\n", __FUNCTION__);
 437                         close(g->s);
 438                         gdb_watch_clear(&g->breakpoints);
 439                         gdb_watch_clear(&g->watchpoints);
 440                         g->avr->state = cpu_Running;    // resume
 441                         g->s = -1;
 442                         return 1;
 443                 }
 444                 if (r == -1) {
 445                         perror("gdb_network_handler recv");
 446                         sleep(1);
 447                         return 1;
 448                 }
 449                 buffer[r] = 0;
 450         //      printf("%s: received %d bytes\n'%s'\n", __FUNCTION__, r, buffer);
 451         //      hdump("gdb", buffer, r);
 452
 453                 uint8_t * src = buffer;
 454                 while (*src == '+' || *src == '-')
 455                         src++;
 456                 // control C -- lets send the guy a nice status packet
 457                 if (*src == 3) {
 458                         src++;
 459                         g->avr->state = cpu_StepDone;
 460                         printf("GDB hit control-c\n");
 461                 }
 462                 if (*src  == '$') {
 463                         // strip checksum
 464                         uint8_t * end = buffer + r - 1;
 465                         while (end > src && *end != '#')
 466                                 *end-- = 0;
 467                         *end = 0;
 468                         src++;
 469                         DBG(printf("GDB command = '%s'\n", src);)
 470
 471                         send(g->s, "+", 1, 0);
 472
 473                         gdb_handle_command(g, (char*)src);
 474                 }
 475         }
 476         return 1;
 477 }
 478
 479 /**
 480  * If an applicable watchpoint exists for addr, stop the cpu and send a status report.
 481  * type is one of AVR_GDB_WATCH_READ, AVR_GDB_WATCH_WRITE depending on the type of access.
 482  */
 483 void avr_gdb_handle_watchpoints(avr_t * avr, uint16_t addr, enum avr_gdb_watch_type type)
 484 {
 485         avr_gdb_t *g = avr->gdb;
 486
 487         int i = gdb_watch_find_range(&g->watchpoints, addr);
 488         if (i == -1) {
 489                 return;
 490         }
 491
 492         int kind = g->watchpoints.points[i].kind;
 493         if (kind & type) {
 494                 /* Send gdb reply (see GDB user manual appendix E.3). */
 495                 char cmd[78];
 496                 sprintf(cmd, "T%02x20:%02x;21:%02x%02x;22:%02x%02x%02x00;%s:%06x;",
 497                                 5, g->avr->data[R_SREG],
 498                                 g->avr->data[R_SPL], g->avr->data[R_SPH],
 499                                 g->avr->pc & 0xff, (g->avr->pc>>8)&0xff, (g->avr->pc>>16)&0xff,
 500                                 kind & AVR_GDB_WATCH_ACCESS ? "awatch" : kind & AVR_GDB_WATCH_WRITE ? "watch" : "rwatch",
 501                                 addr | 0x800000);
 502                 gdb_send_reply(g, cmd);
 503
 504                 avr->state = cpu_Stopped;
 505         }
 506 }
 507
 508 int avr_gdb_processor(avr_t * avr, int sleep)
 509 {
 510         if (!avr || !avr->gdb)
 511                 return 0;
 512         avr_gdb_t * g = avr->gdb;
 513
 514         if (avr->state == cpu_Running && gdb_watch_find(&g->breakpoints, avr->pc) != -1) {
 515                 DBG(printf("avr_gdb_processor hit breakpoint at %08x\n", avr->pc);)
 516                 gdb_send_quick_status(g, 0);
 517                 avr->state = cpu_Stopped;
 518         } else if (avr->state == cpu_StepDone) {
 519                 gdb_send_quick_status(g, 0);
 520                 avr->state = cpu_Stopped;
 521         }
 522         // this also sleeps for a bit
 523         return gdb_network_handler(g, sleep);
 524 }
 525
 526
 527 int avr_gdb_init(avr_t * avr)
 528 {
 529         avr_gdb_t * g = malloc(sizeof(avr_gdb_t));
 530         memset(g, 0, sizeof(avr_gdb_t));
 531
 532         avr->gdb = NULL;
 533
 534         if ((g->listen = socket(PF_INET, SOCK_STREAM, 0)) < 0) {
 535                 fprintf(stderr, "Can't create socket: %s", strerror(errno));
 536                 return -1;
 537         }
 538
 539         int i = 1;
 540         setsockopt(g->listen, SOL_SOCKET, SO_REUSEADDR, &i, sizeof(i));
 541
 542         struct sockaddr_in address = { 0 };
 543         address.sin_family = AF_INET;
 544         address.sin_port = htons (avr->gdb_port);
 545
 546         if (bind(g->listen, (struct sockaddr *) &address, sizeof(address))) {
 547                 fprintf(stderr, "Can not bind socket: %s", strerror(errno));
 548                 return -1;
 549         }
 550         if (listen(g->listen, 1)) {
 551                 perror("listen");
 552                 return -1;
 553         }
 554         printf("avr_gdb_init listening on port %d\n", avr->gdb_port);
 555         g->avr = avr;
 556         g->s = -1;
 557         avr->gdb = g;
 558         // change default run behaviour to use the slightly slower versions
 559         avr->run = avr_callback_run_gdb;
 560         avr->sleep = avr_callback_sleep_gdb;
 561
 562         return 0;
 563 }