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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 typedef struct avr_gdb_t {
  42         avr_t * avr;
  43         int             listen; // listen socket
  44         int             s;              // current gdb connection
  45
  46         uint32_t        watchmap;
  47         struct {
  48                 uint32_t        pc;
  49                 uint32_t        len;
  50                 int kind;
  51         } watch[32];
  52 } avr_gdb_t;
  53
  54
  55 static void gdb_send_reply(avr_gdb_t * g, char * cmd)
  56 {
  57         uint8_t reply[1024];
  58         uint8_t * dst = reply;
  59         uint8_t check = 0;
  60         *dst++ = '$';
  61         while (*cmd) {
  62                 check += *cmd;
  63                 *dst++ = *cmd++;
  64         }
  65         sprintf((char*)dst, "#%02x", check);
  66         DBG(printf("%s '%s'\n", __FUNCTION__, reply);)
  67         send(g->s, reply, dst - reply + 3, 0);
  68 }
  69
  70 static void gdb_send_quick_status(avr_gdb_t * g, uint8_t signal)
  71 {
  72         char cmd[64];
  73
  74         sprintf(cmd, "T%02x20:%02x;21:%02x%02x;22:%02x%02x%02x00;",
  75                 signal ? signal : 5, g->avr->data[R_SREG],
  76                 g->avr->data[R_SPL], g->avr->data[R_SPH],
  77                 g->avr->pc & 0xff, (g->avr->pc>>8)&0xff, (g->avr->pc>>16)&0xff);
  78         gdb_send_reply(g, cmd);
  79 }
  80
  81 static int gdb_change_breakpoint(avr_gdb_t * g, int set, int kind, uint32_t addr, uint32_t len)
  82 {
  83         DBG(printf("set %d kind %d addr %08x len %d (map %08x)\n", set, kind, addr, len, g->watchmap);)
  84         if (set) {
  85                 if (g->watchmap == 0xffffffff)
  86                         return -1;      // map full
  87
  88                 // check to see if it exists
  89                 for (int i = 0; i < 32; i++)
  90                         if ((g->watchmap & (1 << i)) && g->watch[i].pc == addr) {
  91                                 g->watch[i].len = len;
  92                                 return 0;
  93                         }
  94                 for (int i = 0; i < 32; i++)
  95                         if (!(g->watchmap & (1 << i))) {
  96                                 g->watchmap |= (1 << i);
  97                                 g->watch[i].len = len;
  98                                 g->watch[i].pc = addr;
  99                                 g->watch[i].kind = kind;
 100                                 return 0;
 101                         }
 102         } else {
 103                 for (int i = 0; i < 32; i++)
 104                         if ((g->watchmap & (1 << i)) && g->watch[i].pc == addr) {
 105                                 g->watchmap &= ~(1 << i);
 106                                 g->watch[i].len = 0;
 107                                 g->watch[i].pc = 0;
 108                                 g->watch[i].kind = 0;
 109                                 return 0;
 110                         }
 111         }
 112         return -1;
 113 }
 114
 115 static int gdb_write_register(avr_gdb_t * g, int regi, uint8_t * src)
 116 {
 117         switch (regi) {
 118                 case 0 ... 31:
 119                         g->avr->data[regi] = *src;
 120                         return 1;
 121                 case 32:
 122                         g->avr->data[R_SREG] = *src;
 123                         return 1;
 124                 case 33:
 125                         g->avr->data[R_SPL] = src[0];
 126                         g->avr->data[R_SPH] = src[1];
 127                         return 2;
 128                 case 34:
 129                         g->avr->pc = src[0] | (src[1] << 8) | (src[2] << 16) | (src[3] << 24);
 130                         return 4;
 131         }
 132         return 1;
 133 }
 134
 135 static int gdb_read_register(avr_gdb_t * g, int regi, char * rep)
 136 {
 137         switch (regi) {
 138                 case 0 ... 31:
 139                         sprintf(rep, "%02x", g->avr->data[regi]);
 140                         break;
 141                 case 32:
 142                         sprintf(rep, "%02x", g->avr->data[R_SREG]);
 143                         break;
 144                 case 33:
 145                         sprintf(rep, "%02x%02x", g->avr->data[R_SPL], g->avr->data[R_SPH]);
 146                         break;
 147                 case 34:
 148                         sprintf(rep, "%02x%02x%02x00",
 149                                 g->avr->pc & 0xff, (g->avr->pc>>8)&0xff, (g->avr->pc>>16)&0xff);
 150                         break;
 151         }
 152         return strlen(rep);
 153 }
 154
 155 static void gdb_handle_command(avr_gdb_t * g, char * cmd)
 156 {
 157         avr_t * avr = g->avr;
 158         char rep[1024];
 159         uint8_t command = *cmd++;
 160         switch (command) {
 161                 case '?':
 162                         gdb_send_quick_status(g, 0);
 163                         break;
 164                 case 'G': {     // set all general purpose registers
 165                         // get their binary form
 166                         read_hex_string(cmd, (uint8_t*)rep, strlen(cmd));
 167                         uint8_t *src = (uint8_t*)rep;
 168                         for (int i = 0; i < 35; i++)
 169                                 src += gdb_write_register(g, i, src);
 170                         gdb_send_reply(g, "OK");
 171                 }       break;
 172                 case 'g': {     // read all general purpose registers
 173                         char * dst = rep;
 174                         for (int i = 0; i < 35; i++)
 175                                 dst += gdb_read_register(g, i, dst);
 176                         gdb_send_reply(g, rep);
 177                 }       break;
 178                 case 'p': {     // read register
 179                         unsigned int regi = 0;
 180                         sscanf(cmd, "%x", &regi);
 181                         gdb_read_register(g, regi, rep);
 182                         gdb_send_reply(g, rep);
 183                 }       break;
 184                 case 'P': {     // write register
 185                         unsigned int regi = 0;
 186                         char * val = strchr(cmd, '=');
 187                         if (!val)
 188                                 break;
 189                         *val++ = 0;
 190                         sscanf(cmd, "%x", &regi);
 191                         read_hex_string(val, (uint8_t*)rep, strlen(val));
 192                         gdb_write_register(g, regi, (uint8_t*)rep);
 193                         gdb_send_reply(g, "OK");
 194                 }       break;
 195                 case 'm': {     // read memory
 196                         uint32_t addr, len;
 197                         sscanf(cmd, "%x,%x", &addr, &len);
 198                         uint8_t * src = NULL;
 199                         if (addr < 0xffff) {
 200                                 src = avr->flash + addr;
 201                         } else if (addr >= 0x800000 && (addr - 0x800000) <= avr->ramend) {
 202                                 src = avr->data + addr - 0x800000;
 203                         } else if (addr >= 0x810000 && (addr - 0x810000) <= avr->e2end) {
 204                                 avr_eeprom_desc_t ee = {.offset = (addr - 0x810000)};
 205                                 avr_ioctl(avr, AVR_IOCTL_EEPROM_GET, &ee);
 206                                 if (ee.ee)
 207                                         src = ee.ee;
 208                                 else {
 209                                         gdb_send_reply(g, "E01");
 210                                         break;
 211                                 }
 212                         } else if (addr >= 0x800000 && (addr - 0x800000) == avr->ramend+1 && len == 2) {
 213                                 // Allow GDB to read a value just after end of stack.
 214                                 // This is necessary to make instruction stepping work when stack is empty
 215                                 printf("GDB read just past end of stack %08x, %08x; returning zero\n", addr, len);
 216                                 gdb_send_reply(g, "0000");
 217                                 break;
 218                         } else {
 219                                 printf("read memory error %08x, %08x (ramend %04x)\n", addr, len, avr->ramend+1);
 220                                 gdb_send_reply(g, "E01");
 221                                 break;
 222                         }
 223                         char * dst = rep;
 224                         while (len--) {
 225                                 sprintf(dst, "%02x", *src++);
 226                                 dst += 2;
 227                         }
 228                         *dst = 0;
 229                         gdb_send_reply(g, rep);
 230                 }       break;
 231                 case 'M': {     // write memory
 232                         uint32_t addr, len;
 233                         sscanf(cmd, "%x,%x", &addr, &len);
 234                         char * start = strchr(cmd, ':');
 235                         if (!start) {
 236                                 gdb_send_reply(g, "E01");
 237                                 break;
 238                         }
 239                         if (addr < 0xffff) {
 240                                 read_hex_string(start + 1, avr->flash + addr, strlen(start+1));
 241                                 gdb_send_reply(g, "OK");
 242                         } else if (addr >= 0x800000 && (addr - 0x800000) <= avr->ramend) {
 243                                 read_hex_string(start + 1, avr->data + addr - 0x800000, strlen(start+1));
 244                                 gdb_send_reply(g, "OK");
 245                         } else if (addr >= 0x810000 && (addr - 0x810000) <= avr->e2end) {
 246                                 read_hex_string(start + 1, (uint8_t*)rep, strlen(start+1));
 247                                 avr_eeprom_desc_t ee = {.offset = (addr - 0x810000), .size = len, .ee = (uint8_t*)rep };
 248                                 avr_ioctl(avr, AVR_IOCTL_EEPROM_SET, &ee);
 249                                 gdb_send_reply(g, "OK");
 250                         } else {
 251                                 printf("write memory error %08x, %08x\n", addr, len);
 252                                 gdb_send_reply(g, "E01");
 253                         }
 254                 }       break;
 255                 case 'c': {     // continue
 256                         avr->state = cpu_Running;
 257                 }       break;
 258                 case 's': {     // step
 259                         avr->state = cpu_Step;
 260                 }       break;
 261                 case 'r': {     // deprecated, suggested for AVRStudio compatibility
 262                         avr->state = cpu_StepDone;
 263                         avr_reset(avr);
 264                 }       break;
 265                 case 'Z':       // set clear break/watchpoint
 266                 case 'z': {
 267                         uint32_t kind, addr, len;
 268                         sscanf(cmd, "%d,%x,%x", &kind, &addr, &len);
 269 //                      printf("breakbpoint %d, %08x, %08x\n", kind, addr, len);
 270                         switch (kind) {
 271                                 case 0: // software breakpoint
 272                                 case 1: // hardware breakpoint
 273                                         if (addr <= avr->flashend) {
 274                                                 if (gdb_change_breakpoint(g, command == 'Z', kind, addr, len))
 275                                                         gdb_send_reply(g, "E01");
 276                                                 else
 277                                                         gdb_send_reply(g, "OK");
 278                                         } else
 279                                                 gdb_send_reply(g, "E01");               // out of flash address
 280                                         break;
 281                                 // TODO
 282                                 case 2: // write watchpoint
 283                                 case 3: // read watchpoint
 284                                 case 4: // access watchpoint
 285                                 default:
 286                                         gdb_send_reply(g, "");
 287                         }
 288                 }       break;
 289                 default:
 290                         gdb_send_reply(g, "");
 291         }
 292 }
 293
 294 static int gdb_network_handler(avr_gdb_t * g, uint32_t dosleep)
 295 {
 296         fd_set read_set;
 297         int max;
 298         FD_ZERO(&read_set);
 299
 300         if (g->s != -1) {
 301                 FD_SET(g->s, &read_set);
 302                 max = g->s + 1;
 303         } else {
 304                 FD_SET(g->listen, &read_set);
 305                 max = g->listen + 1;
 306         }
 307         struct timeval timo = { 0, dosleep };   // short, but not too short interval
 308         int ret = select(max, &read_set, NULL, NULL, &timo);
 309
 310         if (ret == 0)
 311                 return 0;
 312
 313         if (FD_ISSET(g->listen, &read_set)) {
 314                 g->s = accept(g->listen, NULL, NULL);
 315
 316                 if (g->s == -1) {
 317                         perror("gdb_network_handler accept");
 318                         sleep(5);
 319                         return 1;
 320                 }
 321         int i = 1;
 322         setsockopt (g->s, IPPROTO_TCP, TCP_NODELAY, &i, sizeof (i));
 323                 g->avr->state = cpu_Stopped;
 324                 printf("%s connection opened\n", __FUNCTION__);
 325         }
 326
 327         if (g->s != -1 && FD_ISSET(g->s, &read_set)) {
 328                 uint8_t buffer[1024];
 329
 330                 ssize_t r = recv(g->s, buffer, sizeof(buffer)-1, 0);
 331
 332                 if (r == 0) {
 333                         printf("%s connection closed\n", __FUNCTION__);
 334                         close(g->s);
 335                         g->watchmap = 0;                                // clear breakpoints
 336                         g->avr->state = cpu_Running;    // resume
 337                         g->s = -1;
 338                         return 1;
 339                 }
 340                 if (r == -1) {
 341                         perror("gdb_network_handler recv");
 342                         sleep(1);
 343                         return 1;
 344                 }
 345                 buffer[r] = 0;
 346         //      printf("%s: received %d bytes\n'%s'\n", __FUNCTION__, r, buffer);
 347         //      hdump("gdb", buffer, r);
 348
 349                 uint8_t * src = buffer;
 350                 while (*src == '+' || *src == '-')
 351                         src++;
 352                 // control C -- lets send the guy a nice status packet
 353                 if (*src == 3) {
 354                         src++;
 355                         g->avr->state = cpu_StepDone;
 356                         printf("GDB hit control-c\n");
 357                 }
 358                 if (*src  == '$') {
 359                         // strip checksum
 360                         uint8_t * end = buffer + r - 1;
 361                         while (end > src && *end != '#')
 362                                 *end-- = 0;
 363                         *end = 0;
 364                         src++;
 365                         DBG(printf("GDB command = '%s'\n", src);)
 366
 367                         send(g->s, "+", 1, 0);
 368
 369                         gdb_handle_command(g, (char*)src);
 370                 }
 371         }
 372         return 1;
 373 }
 374
 375 int avr_gdb_processor(avr_t * avr, int sleep)
 376 {
 377         if (!avr || !avr->gdb)
 378                 return 0;
 379         avr_gdb_t * g = avr->gdb;
 380
 381         if (g->watchmap && avr->state == cpu_Running) {
 382                 for (int i = 0; i < 32; i++)
 383                         if ((g->watchmap & (1 << i)) && g->watch[i].pc == avr->pc) {
 384                                 DBG(printf("avr_gdb_processor hit breakpoint at %08x\n", avr->pc);)
 385                                 gdb_send_quick_status(g, 0);
 386                                 avr->state = cpu_Stopped;
 387                         }
 388         }
 389         if (avr->state == cpu_StepDone) {
 390                 gdb_send_quick_status(g, 0);
 391                 avr->state = cpu_Stopped;
 392         }
 393         // this also sleeps for a bit
 394         return gdb_network_handler(g, sleep);
 395 }
 396
 397
 398 int avr_gdb_init(avr_t * avr)
 399 {
 400         avr_gdb_t * g = malloc(sizeof(avr_gdb_t));
 401         memset(g, 0, sizeof(avr_gdb_t));
 402
 403         avr->gdb = NULL;
 404
 405         if ((g->listen = socket(PF_INET, SOCK_STREAM, 0)) < 0) {
 406                 fprintf(stderr, "Can't create socket: %s", strerror(errno));
 407                 return -1;
 408         }
 409
 410         int i = 1;
 411         setsockopt(g->listen, SOL_SOCKET, SO_REUSEADDR, &i, sizeof(i));
 412
 413         struct sockaddr_in address = { 0 };
 414         address.sin_family = AF_INET;
 415         address.sin_port = htons (avr->gdb_port);
 416
 417         if (bind(g->listen, (struct sockaddr *) &address, sizeof(address))) {
 418                 fprintf(stderr, "Can not bind socket: %s", strerror(errno));
 419                 return -1;
 420         }
 421         if (listen(g->listen, 1)) {
 422                 perror("listen");
 423                 return -1;
 424         }
 425         printf("avr_gdb_init listening on port %d\n", avr->gdb_port);
 426         g->avr = avr;
 427         g->s = -1;
 428         avr->gdb = g;
 429         // change default run behaviour to use the slightly slower versions
 430         avr->run = avr_callback_run_gdb;
 431         avr->sleep = avr_callback_sleep_gdb;
 432
 433         return 0;
 434 }