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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
  38 #define DBG(w)
  39
  40 typedef struct avr_gdb_t {
  41         avr_t * avr;
  42         int             listen; // listen socket
  43         int             s;              // current gdb connection
  44
  45         uint32_t        watchmap;
  46         struct {
  47                 uint32_t        pc;
  48                 uint32_t        len;
  49                 int kind;
  50         } watch[32];
  51 } avr_gdb_t;
  52
  53
  54 static void gdb_send_reply(avr_gdb_t * g, char * cmd)
  55 {
  56         uint8_t reply[1024];
  57         uint8_t * dst = reply;
  58         uint8_t check = 0;
  59         *dst++ = '$';
  60         while (*cmd) {
  61                 check += *cmd;
  62                 *dst++ = *cmd++;
  63         }
  64         sprintf((char*)dst, "#%02x", check);
  65         DBG(printf("%s '%s'\n", __FUNCTION__, reply);)
  66         send(g->s, reply, dst - reply + 3, 0);
  67 }
  68
  69 static void gdb_send_quick_status(avr_gdb_t * g, uint8_t signal)
  70 {
  71         char cmd[64];
  72
  73         sprintf(cmd, "T%02x20:%02x;21:%02x%02x;22:%02x%02x%02x00;",
  74                 signal ? signal : 5, g->avr->data[R_SREG],
  75                 g->avr->data[R_SPL], g->avr->data[R_SPH],
  76                 g->avr->pc & 0xff, (g->avr->pc>>8)&0xff, (g->avr->pc>>16)&0xff);
  77         gdb_send_reply(g, cmd);
  78 }
  79
  80 static int gdb_change_breakpoint(avr_gdb_t * g, int set, int kind, uint32_t addr, uint32_t len)
  81 {
  82         DBG(printf("set %d kind %d addr %08x len %d (map %08x)\n", set, kind, addr, len, g->watchmap);)
  83         if (set) {
  84                 if (g->watchmap == 0xffffffff)
  85                         return -1;      // map full
  86
  87                 // check to see if it exists
  88                 for (int i = 0; i < 32; i++)
  89                         if ((g->watchmap & (1 << i)) && g->watch[i].pc == addr) {
  90                                 g->watch[i].len = len;
  91                                 return 0;
  92                         }
  93                 for (int i = 0; i < 32; i++)
  94                         if (!(g->watchmap & (1 << i))) {
  95                                 g->watchmap |= (1 << i);
  96                                 g->watch[i].len = len;
  97                                 g->watch[i].pc = addr;
  98                                 g->watch[i].kind = kind;
  99                                 return 0;
 100                         }
 101         } else {
 102                 for (int i = 0; i < 32; i++)
 103                         if ((g->watchmap & (1 << i)) && g->watch[i].pc == addr) {
 104                                 g->watchmap &= ~(1 << i);
 105                                 g->watch[i].len = 0;
 106                                 g->watch[i].pc = 0;
 107                                 g->watch[i].kind = 0;
 108                                 return 0;
 109                         }
 110         }
 111         return -1;
 112 }
 113
 114 static int gdb_write_register(avr_gdb_t * g, int regi, uint8_t * src)
 115 {
 116         switch (regi) {
 117                 case 0 ... 31:
 118                         g->avr->data[regi] = *src;
 119                         return 1;
 120                 case 32:
 121                         g->avr->data[R_SREG] = *src;
 122                         return 1;
 123                 case 33:
 124                         g->avr->data[R_SPL] = src[0];
 125                         g->avr->data[R_SPH] = src[1];
 126                         return 2;
 127                 case 34:
 128                         g->avr->pc = src[0] | (src[1] << 8) | (src[2] << 16) | (src[3] << 24);
 129                         return 4;
 130         }
 131         return 1;
 132 }
 133
 134 static int gdb_read_register(avr_gdb_t * g, int regi, char * rep)
 135 {
 136         switch (regi) {
 137                 case 0 ... 31:
 138                         sprintf(rep, "%02x", g->avr->data[regi]);
 139                         break;
 140                 case 32:
 141                         sprintf(rep, "%02x", g->avr->data[R_SREG]);
 142                         break;
 143                 case 33:
 144                         sprintf(rep, "%02x%02x", g->avr->data[R_SPL], g->avr->data[R_SPH]);
 145                         break;
 146                 case 34:
 147                         sprintf(rep, "%02x%02x%02x00",
 148                                 g->avr->pc & 0xff, (g->avr->pc>>8)&0xff, (g->avr->pc>>16)&0xff);
 149                         break;
 150         }
 151         return strlen(rep);
 152 }
 153
 154 static void gdb_handle_command(avr_gdb_t * g, char * cmd)
 155 {
 156         avr_t * avr = g->avr;
 157         char rep[1024];
 158         uint8_t command = *cmd++;
 159         switch (command) {
 160                 case '?':
 161                         gdb_send_quick_status(g, 0);
 162                         break;
 163                 case 'G': {     // set all general purpose registers
 164                         // get their binary form
 165                         read_hex_string(cmd, (uint8_t*)rep, strlen(cmd));
 166                         uint8_t *src = (uint8_t*)rep;
 167                         for (int i = 0; i < 35; i++)
 168                                 src += gdb_write_register(g, i, src);
 169                         gdb_send_reply(g, "OK");
 170                 }       break;
 171                 case 'g': {     // read all general purpose registers
 172                         char * dst = rep;
 173                         for (int i = 0; i < 35; i++)
 174                                 dst += gdb_read_register(g, i, dst);
 175                         gdb_send_reply(g, rep);
 176                 }       break;
 177                 case 'p': {     // read register
 178                         unsigned int regi = 0;
 179                         sscanf(cmd, "%x", &regi);
 180                         gdb_read_register(g, regi, rep);
 181                         gdb_send_reply(g, rep);
 182                 }       break;
 183                 case 'P': {     // write register
 184                         unsigned int regi = 0;
 185                         char * val = strchr(cmd, '=');
 186                         if (!val)
 187                                 break;
 188                         *val++ = 0;
 189                         sscanf(cmd, "%x", &regi);
 190                         read_hex_string(val, (uint8_t*)rep, strlen(val));
 191                         gdb_write_register(g, regi, (uint8_t*)rep);
 192                         gdb_send_reply(g, "OK");
 193                 }       break;
 194                 case 'm': {     // read memory
 195                         uint32_t addr, len;
 196                         sscanf(cmd, "%x,%x", &addr, &len);
 197                         uint8_t * src = NULL;
 198                         if (addr < 0xffff) {
 199                                 src = avr->flash + addr;
 200                         } else if (addr >= 0x800000 && (addr - 0x800000) <= avr->ramend) {
 201                                 src = avr->data + addr - 0x800000;
 202                         } else if (addr >= 0x810000 && (addr - 0x810000) <= avr->e2end) {
 203                                 avr_eeprom_desc_t ee = {.offset = (addr - 0x810000)};
 204                                 avr_ioctl(avr, AVR_IOCTL_EEPROM_GET, &ee);
 205                                 if (ee.ee)
 206                                         src = ee.ee;
 207                                 else {
 208                                         gdb_send_reply(g, "E01");
 209                                         break;
 210                                 }
 211                         } else if (addr >= 0x800000 && (addr - 0x800000) == avr->ramend+1 && len == 2) {
 212                                 // Allow GDB to read a value just after end of stack.
 213                                 // This is necessary to make instruction stepping work when stack is empty
 214                                 printf("GDB read just past end of stack %08x, %08x; returning zero\n", addr, len);
 215                                 gdb_send_reply(g, "0000");
 216                                 break;
 217                         } else {
 218                                 printf("read memory error %08x, %08x (ramend %04x)\n", addr, len, avr->ramend+1);
 219                                 gdb_send_reply(g, "E01");
 220                                 break;
 221                         }
 222                         char * dst = rep;
 223                         while (len--) {
 224                                 sprintf(dst, "%02x", *src++);
 225                                 dst += 2;
 226                         }
 227                         *dst = 0;
 228                         gdb_send_reply(g, rep);
 229                 }       break;
 230                 case 'M': {     // write memory
 231                         uint32_t addr, len;
 232                         sscanf(cmd, "%x,%x", &addr, &len);
 233                         char * start = strchr(cmd, ':');
 234                         if (!start) {
 235                                 gdb_send_reply(g, "E01");
 236                                 break;
 237                         }
 238                         if (addr < 0xffff) {
 239                                 read_hex_string(start + 1, avr->flash + addr, strlen(start+1));
 240                                 gdb_send_reply(g, "OK");
 241                         } else if (addr >= 0x800000 && (addr - 0x800000) <= avr->ramend) {
 242                                 read_hex_string(start + 1, avr->data + addr - 0x800000, strlen(start+1));
 243                                 gdb_send_reply(g, "OK");
 244                         } else if (addr >= 0x810000 && (addr - 0x810000) <= avr->e2end) {
 245                                 read_hex_string(start + 1, (uint8_t*)rep, strlen(start+1));
 246                                 avr_eeprom_desc_t ee = {.offset = (addr - 0x810000), .size = len, .ee = (uint8_t*)rep };
 247                                 avr_ioctl(avr, AVR_IOCTL_EEPROM_SET, &ee);
 248                                 gdb_send_reply(g, "OK");
 249                         } else {
 250                                 printf("write memory error %08x, %08x\n", addr, len);
 251                                 gdb_send_reply(g, "E01");
 252                         }
 253                 }       break;
 254                 case 'c': {     // continue
 255                         avr->state = cpu_Running;
 256                 }       break;
 257                 case 's': {     // step
 258                         avr->state = cpu_Step;
 259                 }       break;
 260                 case 'r': {     // deprecated, suggested for AVRStudio compatibility
 261                         avr->state = cpu_StepDone;
 262                         avr_reset(avr);
 263                 }       break;
 264                 case 'Z':       // set clear break/watchpoint
 265                 case 'z': {
 266                         uint32_t kind, addr, len;
 267                         sscanf(cmd, "%d,%x,%x", &kind, &addr, &len);
 268 //                      printf("breakbpoint %d, %08x, %08x\n", kind, addr, len);
 269                         switch (kind) {
 270                                 case 0: // software breakpoint
 271                                 case 1: // hardware breakpoint
 272                                         if (addr <= avr->flashend) {
 273                                                 if (gdb_change_breakpoint(g, command == 'Z', kind, addr, len))
 274                                                         gdb_send_reply(g, "E01");
 275                                                 else
 276                                                         gdb_send_reply(g, "OK");
 277                                         } else
 278                                                 gdb_send_reply(g, "E01");               // out of flash address
 279                                         break;
 280                                 // TODO
 281                                 case 2: // write watchpoint
 282                                 case 3: // read watchpoint
 283                                 case 4: // access watchpoint
 284                                 default:
 285                                         gdb_send_reply(g, "");
 286                         }
 287                 }       break;
 288                 default:
 289                         gdb_send_reply(g, "");
 290         }
 291 }
 292
 293 static int gdb_network_handler(avr_gdb_t * g, uint32_t dosleep)
 294 {
 295         fd_set read_set;
 296         int max;
 297         FD_ZERO(&read_set);
 298
 299         if (g->s != -1) {
 300                 FD_SET(g->s, &read_set);
 301                 max = g->s + 1;
 302         } else {
 303                 FD_SET(g->listen, &read_set);
 304                 max = g->listen + 1;
 305         }
 306         struct timeval timo = { 0, dosleep };   // short, but not too short interval
 307         int ret = select(max, &read_set, NULL, NULL, &timo);
 308
 309         if (ret == 0)
 310                 return 0;
 311
 312         if (FD_ISSET(g->listen, &read_set)) {
 313                 g->s = accept(g->listen, NULL, NULL);
 314
 315                 if (g->s == -1) {
 316                         perror("gdb_network_handler accept");
 317                         sleep(5);
 318                         return 1;
 319                 }
 320         int i = 1;
 321         setsockopt (g->s, IPPROTO_TCP, TCP_NODELAY, &i, sizeof (i));
 322                 g->avr->state = cpu_Stopped;
 323                 printf("%s connection opened\n", __FUNCTION__);
 324         }
 325
 326         if (g->s != -1 && FD_ISSET(g->s, &read_set)) {
 327                 uint8_t buffer[1024];
 328
 329                 ssize_t r = recv(g->s, buffer, sizeof(buffer)-1, 0);
 330
 331                 if (r == 0) {
 332                         printf("%s connection closed\n", __FUNCTION__);
 333                         close(g->s);
 334                         g->watchmap = 0;                                // clear breakpoints
 335                         g->avr->state = cpu_Running;    // resume
 336                         g->s = -1;
 337                         return 1;
 338                 }
 339                 if (r == -1) {
 340                         perror("gdb_network_handler recv");
 341                         sleep(1);
 342                         return 1;
 343                 }
 344                 buffer[r] = 0;
 345         //      printf("%s: received %d bytes\n'%s'\n", __FUNCTION__, r, buffer);
 346         //      hdump("gdb", buffer, r);
 347
 348                 uint8_t * src = buffer;
 349                 while (*src == '+' || *src == '-')
 350                         src++;
 351                 // control C -- lets send the guy a nice status packet
 352                 if (*src == 3) {
 353                         src++;
 354                         g->avr->state = cpu_StepDone;
 355                         printf("GDB hit control-c\n");
 356                 }
 357                 if (*src  == '$') {
 358                         // strip checksum
 359                         uint8_t * end = buffer + r - 1;
 360                         while (end > src && *end != '#')
 361                                 *end-- = 0;
 362                         *end = 0;
 363                         src++;
 364                         DBG(printf("GDB command = '%s'\n", src);)
 365
 366                         send(g->s, "+", 1, 0);
 367
 368                         gdb_handle_command(g, (char*)src);
 369                 }
 370         }
 371         return 1;
 372 }
 373
 374 int avr_gdb_processor(avr_t * avr, int sleep)
 375 {
 376         if (!avr || !avr->gdb)
 377                 return 0;
 378         avr_gdb_t * g = avr->gdb;
 379
 380         if (g->watchmap && avr->state == cpu_Running) {
 381                 for (int i = 0; i < 32; i++)
 382                         if ((g->watchmap & (1 << i)) && g->watch[i].pc == avr->pc) {
 383                                 DBG(printf("avr_gdb_processor hit breakpoint at %08x\n", avr->pc);)
 384                                 gdb_send_quick_status(g, 0);
 385                                 avr->state = cpu_Stopped;
 386                         }
 387         }
 388         if (avr->state == cpu_StepDone) {
 389                 gdb_send_quick_status(g, 0);
 390                 avr->state = cpu_Stopped;
 391         }
 392         // this also sleeps for a bit
 393         return gdb_network_handler(g, sleep);
 394 }
 395
 396
 397 int avr_gdb_init(avr_t * avr)
 398 {
 399         avr_gdb_t * g = malloc(sizeof(avr_gdb_t));
 400         memset(g, 0, sizeof(avr_gdb_t));
 401
 402         avr->gdb = NULL;
 403
 404         if ((g->listen = socket(PF_INET, SOCK_STREAM, 0)) < 0) {
 405                 fprintf(stderr, "Can't create socket: %s", strerror(errno));
 406                 return -1;
 407         }
 408
 409         int i = 1;
 410         setsockopt(g->listen, SOL_SOCKET, SO_REUSEADDR, &i, sizeof(i));
 411
 412         struct sockaddr_in address = { 0 };
 413         address.sin_family = AF_INET;
 414         address.sin_port = htons (avr->gdb_port);
 415
 416         if (bind(g->listen, (struct sockaddr *) &address, sizeof(address))) {
 417                 fprintf(stderr, "Can not bind socket: %s", strerror(errno));
 418                 return -1;
 419         }
 420         if (listen(g->listen, 1)) {
 421                 perror("listen");
 422                 return -1;
 423         }
 424         printf("avr_gdb_init listening on port %d\n", avr->gdb_port);
 425         g->avr = avr;
 426         g->s = -1;
 427         avr->gdb = g;
 428
 429         return 0;
 430 }