kgdb_stub.c revision 1.1
1 /* $NetBSD: kgdb_stub.c,v 1.1 1997/02/12 00:51:47 gwr Exp $ */ 2 3 /* 4 * Copyright (c) 1990, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This software was developed by the Computer Systems Engineering group 8 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and 9 * contributed to Berkeley. 10 * 11 * All advertising materials mentioning features or use of this software 12 * must display the following acknowledgement: 13 * This product includes software developed by the University of 14 * California, Lawrence Berkeley Laboratories. 15 * 16 * Redistribution and use in source and binary forms, with or without 17 * modification, are permitted provided that the following conditions 18 * are met: 19 * 1. Redistributions of source code must retain the above copyright 20 * notice, this list of conditions and the following disclaimer. 21 * 2. Redistributions in binary form must reproduce the above copyright 22 * notice, this list of conditions and the following disclaimer in the 23 * documentation and/or other materials provided with the distribution. 24 * 3. All advertising materials mentioning features or use of this software 25 * must display the following acknowledgement: 26 * This product includes software developed by the University of 27 * California, Berkeley and its contributors. 28 * 4. Neither the name of the University nor the names of its contributors 29 * may be used to endorse or promote products derived from this software 30 * without specific prior written permission. 31 * 32 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 33 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 34 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 35 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 36 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 37 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 38 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 39 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 40 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 41 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 42 * SUCH DAMAGE. 43 * 44 * @(#)kgdb_stub.c 8.4 (Berkeley) 1/12/94 45 */ 46 47 /* 48 * "Stub" to allow remote cpu to debug over a serial line using gdb. 49 */ 50 51 #include <sys/param.h> 52 #include <sys/systm.h> 53 #include <sys/kgdb.h> 54 55 /* #define DEBUG_KGDB XXX */ 56 57 /* XXX: Maybe these should be in the MD files? */ 58 #ifndef KGDBDEV 59 #define KGDBDEV -1 60 #endif 61 #ifndef KGDBRATE 62 #define KGDBRATE 19200 63 #endif 64 65 int kgdb_dev = KGDBDEV; /* remote debugging device (-1 if none) */ 66 int kgdb_rate = KGDBRATE; /* remote debugging baud rate */ 67 int kgdb_active = 0; /* remote debugging active if != 0 */ 68 int kgdb_debug_init = 0; /* != 0 waits for remote at system init */ 69 int kgdb_debug_panic = 0; /* != 0 waits for remote on panic */ 70 label_t *kgdb_recover = 0; 71 72 static void kgdb_copy __P((void *, void *, int)); 73 /* static void kgdb_zero __P((void *, int)); */ 74 static void kgdb_send __P((u_char *)); 75 static int kgdb_recv __P((u_char *, int)); 76 static int digit2i __P((u_char)); 77 static u_char i2digit __P((int)); 78 static void mem2hex __P((void *, void *, int)); 79 static u_char *hex2mem __P((void *, u_char *, int)); 80 static vm_offset_t hex2i __P((u_char **)); 81 82 static int (*kgdb_getc) __P((void *)); 83 static void (*kgdb_putc) __P((void *, int)); 84 static void *kgdb_ioarg; 85 86 static u_char buffer[KGDB_BUFLEN]; 87 static kgdb_reg_t gdb_regs[KGDB_NUMREGS]; 88 89 #define GETC() ((*kgdb_getc)(kgdb_ioarg)) 90 #define PUTC(c) ((*kgdb_putc)(kgdb_ioarg, c)) 91 #define PUTESC(c) do { \ 92 if (c == FRAME_END) { \ 93 PUTC(FRAME_ESCAPE); \ 94 c = TRANS_FRAME_END; \ 95 } else if (c == FRAME_ESCAPE) { \ 96 PUTC(FRAME_ESCAPE); \ 97 c = TRANS_FRAME_ESCAPE; \ 98 } else if (c == FRAME_START) { \ 99 PUTC(FRAME_ESCAPE); \ 100 c = TRANS_FRAME_START; \ 101 } \ 102 PUTC(c); \ 103 } while (0) 104 105 /* 106 * This little routine exists simply so that bcopy() can be debugged. 107 */ 108 static void 109 kgdb_copy(vsrc, vdst, len) 110 void *vsrc, *vdst; 111 int len; 112 { 113 char *src = vsrc; 114 char *dst = vdst; 115 116 while (--len >= 0) 117 *dst++ = *src++; 118 } 119 120 #if 0 121 /* ditto for bzero */ 122 static void 123 kgdb_zero(vptr, len) 124 void *vptr; 125 int len; 126 { 127 char *ptr = vptr; 128 129 while (--len >= 0) 130 *ptr++ = (char) 0; 131 } 132 #endif 133 134 /* 135 * Convert a hex digit into an integer. 136 * This returns -1 if the argument passed is no 137 * valid hex digit. 138 */ 139 static int 140 digit2i(c) 141 u_char c; 142 { 143 if (c >= '0' && c <= '9') 144 return(c - '0'); 145 else if (c >= 'a' && c <= 'f') 146 return(c - 'a' + 10); 147 else if (c >= 'A' && c <= 'F') 148 149 return(c - 'A' + 10); 150 else 151 return(-1); 152 } 153 154 /* 155 * Convert the low 4 bits of an integer into 156 * an hex digit. 157 */ 158 static u_char 159 i2digit(n) 160 int n; 161 { 162 return("0123456789abcdef"[n & 0x0f]); 163 } 164 165 /* 166 * Convert a byte array into an hex string. 167 */ 168 static void 169 mem2hex(vdst, vsrc, len) 170 void *vdst, *vsrc; 171 int len; 172 { 173 u_char *dst = vdst; 174 u_char *src = vsrc; 175 176 while (len--) { 177 *dst++ = i2digit(*src >> 4); 178 *dst++ = i2digit(*src++); 179 } 180 *dst = '\0'; 181 } 182 183 /* 184 * Convert an hex string into a byte array. 185 * This returns a pointer to the character following 186 * the last valid hex digit. If the string ends in 187 * the middle of a byte, NULL is returned. 188 */ 189 static u_char * 190 hex2mem(vdst, src, maxlen) 191 void *vdst; 192 u_char *src; 193 int maxlen; 194 { 195 u_char *dst = vdst; 196 int msb, lsb; 197 198 while (*src && maxlen--) { 199 msb = digit2i(*src++); 200 if (msb < 0) 201 return(src - 1); 202 lsb = digit2i(*src++); 203 if (lsb < 0) 204 return(NULL); 205 *dst++ = (msb << 4) | lsb; 206 } 207 return(src); 208 } 209 210 /* 211 * Convert an hex string into an integer. 212 * This returns a pointer to the character following 213 * the last valid hex digit. 214 */ 215 static vm_offset_t 216 hex2i(srcp) 217 u_char **srcp; 218 { 219 char *src = *srcp; 220 vm_offset_t r = 0; 221 int nibble; 222 223 while ((nibble = digit2i(*src)) >= 0) { 224 r *= 16; 225 r += nibble; 226 src++; 227 } 228 *srcp = src; 229 return(r); 230 } 231 232 /* 233 * Send a packet. 234 */ 235 static void 236 kgdb_send(bp) 237 u_char *bp; 238 { 239 u_char *p; 240 u_char csum, c; 241 242 #ifdef DEBUG_KGDB 243 printf("kgdb_send: %s\n", bp); 244 #endif 245 do { 246 p = bp; 247 PUTC(KGDB_START); 248 for (csum = 0; (c = *p); p++) { 249 PUTC(c); 250 csum += c; 251 } 252 PUTC(KGDB_END); 253 PUTC(i2digit(csum >> 4)); 254 PUTC(i2digit(csum)); 255 } while ((c = GETC() & 0x7f) == KGDB_BADP); 256 } 257 258 /* 259 * Receive a packet. 260 */ 261 static int 262 kgdb_recv(bp, maxlen) 263 u_char *bp; 264 int maxlen; 265 { 266 u_char *p; 267 int c, csum; 268 int len; 269 270 do { 271 p = bp; 272 csum = len = 0; 273 while ((c = GETC()) != KGDB_START) 274 ; 275 276 while ((c = GETC()) != KGDB_END && len < maxlen) { 277 c &= 0x7f; 278 csum += c; 279 *p++ = c; 280 len++; 281 } 282 csum &= 0xff; 283 *p = '\0'; 284 285 if (len >= maxlen) { 286 PUTC(KGDB_BADP); 287 continue; 288 } 289 290 csum -= digit2i(GETC()) * 16; 291 csum -= digit2i(GETC()); 292 293 if (csum == 0) { 294 PUTC(KGDB_GOODP); 295 /* Sequence present? */ 296 if (bp[2] == ':') { 297 PUTC(bp[0]); 298 PUTC(bp[1]); 299 len -= 3; 300 kgdb_copy(bp + 3, bp, len); 301 } 302 break; 303 } 304 PUTC(KGDB_BADP); 305 } while (1); 306 #ifdef DEBUG_KGDB 307 printf("kgdb_recv: %s\n", bp); 308 #endif 309 return(len); 310 } 311 312 /* 313 * This is called by the approprite tty driver. 314 * In our case, by dev/scn.c:scn_kgdb_init() 315 */ 316 void 317 kgdb_attach(getfn, putfn, ioarg) 318 int (*getfn) __P((void *)); 319 void (*putfn) __P((void *, int)); 320 void *ioarg; 321 { 322 kgdb_getc = getfn; 323 kgdb_putc = putfn; 324 kgdb_ioarg = ioarg; 325 } 326 327 /* 328 * This function does all command procesing for interfacing to 329 * a remote gdb. Note that the error codes are ignored by gdb 330 * at present, but might eventually become meaningful. (XXX) 331 * It might makes sense to use POSIX errno values, because 332 * that is what the gdb/remote.c functions want to return. 333 */ 334 int 335 kgdb_trap(type, regs) 336 int type; 337 db_regs_t *regs; 338 { 339 label_t jmpbuf; 340 vm_offset_t addr; 341 size_t len; 342 u_char *p; 343 344 if (kgdb_dev < 0 || kgdb_getc == NULL) { 345 /* not debugging */ 346 return (0); 347 } 348 349 /* Detect and recover from unexpected traps. */ 350 if (kgdb_recover != 0) { 351 printf("kgdb: caught trap 0x%x at %p\n", 352 type, (void*)PC_REGS(regs)); 353 kgdb_send("E0E"); /* 14==EFAULT */ 354 longjmp(kgdb_recover); 355 } 356 357 /* 358 * On the first entry here, we expect that gdb is not yet 359 * listening to us, so just enter the interaction loop. 360 * After the debugger is "active" (connected) it wil be 361 * waiting for a "signaled" message from us. 362 */ 363 if (kgdb_active == 0) { 364 if (!IS_BREAKPOINT_TRAP(type, 0)) { 365 /* No debugger active -- let trap handle this. */ 366 return (0); 367 } 368 kgdb_active = 1; 369 } else { 370 /* Tell remote host that an exception has occured. */ 371 sprintf(buffer, "S%02x", kgdb_signal(type)); 372 kgdb_send(buffer); 373 } 374 375 /* Stick frame regs into our reg cache. */ 376 kgdb_getregs(regs, gdb_regs); 377 378 /* 379 * Interact with gdb until it lets us go. 380 * If we cause a trap, resume here. 381 */ 382 (void) setjmp((kgdb_recover = &jmpbuf)); 383 for (;;) { 384 kgdb_recv(buffer, sizeof(buffer)); 385 switch (buffer[0]) { 386 387 default: 388 /* Unknown command. */ 389 kgdb_send(""); 390 continue; 391 392 case KGDB_SIGNAL: 393 /* 394 * if this command came from a running gdb, 395 * answer it -- the other guy has no way of 396 * knowing if we're in or out of this loop 397 * when he issues a "remote-signal". 398 */ 399 sprintf(buffer, "S%02x", kgdb_signal(type)); 400 kgdb_send(buffer); 401 continue; 402 403 case KGDB_REG_R: 404 mem2hex(buffer, gdb_regs, sizeof(gdb_regs)); 405 kgdb_send(buffer); 406 continue; 407 408 case KGDB_REG_W: 409 p = hex2mem(gdb_regs, buffer + 1, sizeof(gdb_regs)); 410 if (p == NULL || *p != '\0') 411 kgdb_send("E01"); 412 else { 413 kgdb_setregs(regs, gdb_regs); 414 kgdb_send("OK"); 415 } 416 continue; 417 418 case KGDB_MEM_R: 419 p = buffer + 1; 420 addr = hex2i(&p); 421 if (*p++ != ',') { 422 kgdb_send("E02"); 423 continue; 424 } 425 len = hex2i(&p); 426 if (*p != '\0') { 427 kgdb_send("E03"); 428 continue; 429 } 430 if (len > sizeof(buffer) / 2) { 431 kgdb_send("E04"); 432 continue; 433 } 434 if (kgdb_acc(addr, len) == 0) { 435 kgdb_send("E05"); 436 continue; 437 } 438 db_read_bytes(addr, (size_t)len, 439 (char *)buffer + sizeof(buffer) / 2); 440 mem2hex(buffer, buffer + sizeof(buffer) / 2, len); 441 kgdb_send(buffer); 442 continue; 443 444 case KGDB_MEM_W: 445 p = buffer + 1; 446 addr = hex2i(&p); 447 if (*p++ != ',') { 448 kgdb_send("E06"); 449 continue; 450 } 451 len = hex2i(&p); 452 if (*p++ != ':') { 453 kgdb_send("E07"); 454 continue; 455 } 456 if (len > (sizeof(buffer) - (p - buffer))) { 457 kgdb_send("E08"); 458 continue; 459 } 460 p = hex2mem(buffer, p, sizeof(buffer)); 461 if (p == NULL) { 462 kgdb_send("E09"); 463 continue; 464 } 465 if (kgdb_acc(addr, len) == 0) { 466 kgdb_send("E0A"); 467 continue; 468 } 469 db_write_bytes(addr, (size_t)len, (char *)buffer); 470 kgdb_send("OK"); 471 continue; 472 473 case KGDB_KILL: 474 kgdb_active = 0; 475 printf("kgdb detached\n"); 476 db_clear_single_step(regs); 477 goto out; 478 479 case KGDB_CONT: 480 if (buffer[1]) { 481 p = buffer + 1; 482 addr = hex2i(&p); 483 if (*p) { 484 kgdb_send("E0B"); 485 continue; 486 } 487 PC_REGS(regs) = addr; 488 } 489 db_clear_single_step(regs); 490 goto out; 491 492 case KGDB_STEP: 493 if (buffer[1]) { 494 p = buffer + 1; 495 addr = hex2i(&p); 496 if (*p) { 497 kgdb_send("E0B"); 498 continue; 499 } 500 PC_REGS(regs) = addr; 501 } 502 db_set_single_step(regs); 503 goto out; 504 } 505 } 506 out: 507 kgdb_recover = 0; 508 return (1); 509 } 510
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