1 /* 2 * Kernel Debug Core 3 * 4 * Maintainer: Jason Wessel <jason.wessel@windriver.com> 5 * 6 * Copyright (C) 2000-2001 VERITAS Software Corporation. 7 * Copyright (C) 2002-2004 Timesys Corporation 8 * Copyright (C) 2003-2004 Amit S. Kale <amitkale@linsyssoft.com> 9 * Copyright (C) 2004 Pavel Machek <pavel@suse.cz> 10 * Copyright (C) 2004-2006 Tom Rini <trini@kernel.crashing.org> 11 * Copyright (C) 2004-2006 LinSysSoft Technologies Pvt. Ltd. 12 * Copyright (C) 2005-2009 Wind River Systems, Inc. 13 * Copyright (C) 2007 MontaVista Software, Inc. 14 * Copyright (C) 2008 Red Hat, Inc., Ingo Molnar <mingo@redhat.com> 15 * 16 * Contributors at various stages not listed above: 17 * Jason Wessel ( jason.wessel@windriver.com ) 18 * George Anzinger <george@mvista.com> 19 * Anurekh Saxena (anurekh.saxena@timesys.com) 20 * Lake Stevens Instrument Division (Glenn Engel) 21 * Jim Kingdon, Cygnus Support. 22 * 23 * Original KGDB stub: David Grothe <dave@gcom.com>, 24 * Tigran Aivazian <tigran@sco.com> 25 * 26 * This file is licensed under the terms of the GNU General Public License 27 * version 2. This program is licensed "as is" without any warranty of any 28 * kind, whether express or implied. 29 */ 30 31 #include <linux/kernel.h> 32 #include <linux/kgdb.h> 33 #include <linux/kdb.h> 34 #include <linux/reboot.h> 35 #include <linux/uaccess.h> 36 #include <asm/cacheflush.h> 37 #include <asm/unaligned.h> 38 #include "debug_core.h" 39 40 #define KGDB_MAX_THREAD_QUERY 17 41 42 /* Our I/O buffers. */ 43 static char remcom_in_buffer[BUFMAX]; 44 static char remcom_out_buffer[BUFMAX]; 45 46 /* Storage for the registers, in GDB format. */ 47 static unsigned long gdb_regs[(NUMREGBYTES + 48 sizeof(unsigned long) - 1) / 49 sizeof(unsigned long)]; 50 51 /* 52 * GDB remote protocol parser: 53 */ 54 55 static int hex(char ch) 56 { 57 if ((ch >= 'a') && (ch <= 'f')) 58 return ch - 'a' + 10; 59 if ((ch >= '0') && (ch <= '9')) 60 return ch - '0'; 61 if ((ch >= 'A') && (ch <= 'F')) 62 return ch - 'A' + 10; 63 return -1; 64 } 65 66 #ifdef CONFIG_KGDB_KDB 67 static int gdbstub_read_wait(void) 68 { 69 int ret = -1; 70 int i; 71 72 /* poll any additional I/O interfaces that are defined */ 73 while (ret < 0) 74 for (i = 0; kdb_poll_funcs[i] != NULL; i++) { 75 ret = kdb_poll_funcs[i](); 76 if (ret > 0) 77 break; 78 } 79 return ret; 80 } 81 #else 82 static int gdbstub_read_wait(void) 83 { 84 int ret = dbg_io_ops->read_char(); 85 while (ret == NO_POLL_CHAR) 86 ret = dbg_io_ops->read_char(); 87 return ret; 88 } 89 #endif 90 /* scan for the sequence $<data>#<checksum> */ 91 static void get_packet(char *buffer) 92 { 93 unsigned char checksum; 94 unsigned char xmitcsum; 95 int count; 96 char ch; 97 98 do { 99 /* 100 * Spin and wait around for the start character, ignore all 101 * other characters: 102 */ 103 while ((ch = (gdbstub_read_wait())) != '$') 104 /* nothing */; 105 106 kgdb_connected = 1; 107 checksum = 0; 108 xmitcsum = -1; 109 110 count = 0; 111 112 /* 113 * now, read until a # or end of buffer is found: 114 */ 115 while (count < (BUFMAX - 1)) { 116 ch = gdbstub_read_wait(); 117 if (ch == '#') 118 break; 119 checksum = checksum + ch; 120 buffer[count] = ch; 121 count = count + 1; 122 } 123 buffer[count] = 0; 124 125 if (ch == '#') { 126 xmitcsum = hex(gdbstub_read_wait()) << 4; 127 xmitcsum += hex(gdbstub_read_wait()); 128 129 if (checksum != xmitcsum) 130 /* failed checksum */ 131 dbg_io_ops->write_char('-'); 132 else 133 /* successful transfer */ 134 dbg_io_ops->write_char('+'); 135 if (dbg_io_ops->flush) 136 dbg_io_ops->flush(); 137 } 138 } while (checksum != xmitcsum); 139 } 140 141 /* 142 * Send the packet in buffer. 143 * Check for gdb connection if asked for. 144 */ 145 static void put_packet(char *buffer) 146 { 147 unsigned char checksum; 148 int count; 149 char ch; 150 151 /* 152 * $<packet info>#<checksum>. 153 */ 154 while (1) { 155 dbg_io_ops->write_char('$'); 156 checksum = 0; 157 count = 0; 158 159 while ((ch = buffer[count])) { 160 dbg_io_ops->write_char(ch); 161 checksum += ch; 162 count++; 163 } 164 165 dbg_io_ops->write_char('#'); 166 dbg_io_ops->write_char(hex_asc_hi(checksum)); 167 dbg_io_ops->write_char(hex_asc_lo(checksum)); 168 if (dbg_io_ops->flush) 169 dbg_io_ops->flush(); 170 171 /* Now see what we get in reply. */ 172 ch = gdbstub_read_wait(); 173 174 if (ch == 3) 175 ch = gdbstub_read_wait(); 176 177 /* If we get an ACK, we are done. */ 178 if (ch == '+') 179 return; 180 181 /* 182 * If we get the start of another packet, this means 183 * that GDB is attempting to reconnect. We will NAK 184 * the packet being sent, and stop trying to send this 185 * packet. 186 */ 187 if (ch == '$') { 188 dbg_io_ops->write_char('-'); 189 if (dbg_io_ops->flush) 190 dbg_io_ops->flush(); 191 return; 192 } 193 } 194 } 195 196 static char gdbmsgbuf[BUFMAX + 1]; 197 198 void gdbstub_msg_write(const char *s, int len) 199 { 200 char *bufptr; 201 int wcount; 202 int i; 203 204 if (len == 0) 205 len = strlen(s); 206 207 /* 'O'utput */ 208 gdbmsgbuf[0] = 'O'; 209 210 /* Fill and send buffers... */ 211 while (len > 0) { 212 bufptr = gdbmsgbuf + 1; 213 214 /* Calculate how many this time */ 215 if ((len << 1) > (BUFMAX - 2)) 216 wcount = (BUFMAX - 2) >> 1; 217 else 218 wcount = len; 219 220 /* Pack in hex chars */ 221 for (i = 0; i < wcount; i++) 222 bufptr = pack_hex_byte(bufptr, s[i]); 223 *bufptr = '\0'; 224 225 /* Move up */ 226 s += wcount; 227 len -= wcount; 228 229 /* Write packet */ 230 put_packet(gdbmsgbuf); 231 } 232 } 233 234 /* 235 * Convert the memory pointed to by mem into hex, placing result in 236 * buf. Return a pointer to the last char put in buf (null). May 237 * return an error. 238 */ 239 int kgdb_mem2hex(char *mem, char *buf, int count) 240 { 241 char *tmp; 242 int err; 243 244 /* 245 * We use the upper half of buf as an intermediate buffer for the 246 * raw memory copy. Hex conversion will work against this one. 247 */ 248 tmp = buf + count; 249 250 err = probe_kernel_read(tmp, mem, count); 251 if (!err) { 252 while (count > 0) { 253 buf = pack_hex_byte(buf, *tmp); 254 tmp++; 255 count--; 256 } 257 258 *buf = 0; 259 } 260 261 return err; 262 } 263 264 /* 265 * Convert the hex array pointed to by buf into binary to be placed in 266 * mem. Return a pointer to the character AFTER the last byte 267 * written. May return an error. 268 */ 269 int kgdb_hex2mem(char *buf, char *mem, int count) 270 { 271 char *tmp_raw; 272 char *tmp_hex; 273 274 /* 275 * We use the upper half of buf as an intermediate buffer for the 276 * raw memory that is converted from hex. 277 */ 278 tmp_raw = buf + count * 2; 279 280 tmp_hex = tmp_raw - 1; 281 while (tmp_hex >= buf) { 282 tmp_raw--; 283 *tmp_raw = hex(*tmp_hex--); 284 *tmp_raw |= hex(*tmp_hex--) << 4; 285 } 286 287 return probe_kernel_write(mem, tmp_raw, count); 288 } 289 290 /* 291 * While we find nice hex chars, build a long_val. 292 * Return number of chars processed. 293 */ 294 int kgdb_hex2long(char **ptr, unsigned long *long_val) 295 { 296 int hex_val; 297 int num = 0; 298 int negate = 0; 299 300 *long_val = 0; 301 302 if (**ptr == '-') { 303 negate = 1; 304 (*ptr)++; 305 } 306 while (**ptr) { 307 hex_val = hex(**ptr); 308 if (hex_val < 0) 309 break; 310 311 *long_val = (*long_val << 4) | hex_val; 312 num++; 313 (*ptr)++; 314 } 315 316 if (negate) 317 *long_val = -*long_val; 318 319 return num; 320 } 321 322 /* 323 * Copy the binary array pointed to by buf into mem. Fix $, #, and 324 * 0x7d escaped with 0x7d. Return -EFAULT on failure or 0 on success. 325 * The input buf is overwitten with the result to write to mem. 326 */ 327 static int kgdb_ebin2mem(char *buf, char *mem, int count) 328 { 329 int size = 0; 330 char *c = buf; 331 332 while (count-- > 0) { 333 c[size] = *buf++; 334 if (c[size] == 0x7d) 335 c[size] = *buf++ ^ 0x20; 336 size++; 337 } 338 339 return probe_kernel_write(mem, c, size); 340 } 341 342 /* Write memory due to an 'M' or 'X' packet. */ 343 static int write_mem_msg(int binary) 344 { 345 char *ptr = &remcom_in_buffer[1]; 346 unsigned long addr; 347 unsigned long length; 348 int err; 349 350 if (kgdb_hex2long(&ptr, &addr) > 0 && *(ptr++) == ',' && 351 kgdb_hex2long(&ptr, &length) > 0 && *(ptr++) == ':') { 352 if (binary) 353 err = kgdb_ebin2mem(ptr, (char *)addr, length); 354 else 355 err = kgdb_hex2mem(ptr, (char *)addr, length); 356 if (err) 357 return err; 358 if (CACHE_FLUSH_IS_SAFE) 359 flush_icache_range(addr, addr + length); 360 return 0; 361 } 362 363 return -EINVAL; 364 } 365 366 static void error_packet(char *pkt, int error) 367 { 368 error = -error; 369 pkt[0] = 'E'; 370 pkt[1] = hex_asc[(error / 10)]; 371 pkt[2] = hex_asc[(error % 10)]; 372 pkt[3] = '\0'; 373 } 374 375 /* 376 * Thread ID accessors. We represent a flat TID space to GDB, where 377 * the per CPU idle threads (which under Linux all have PID 0) are 378 * remapped to negative TIDs. 379 */ 380 381 #define BUF_THREAD_ID_SIZE 16 382 383 static char *pack_threadid(char *pkt, unsigned char *id) 384 { 385 char *limit; 386 387 limit = pkt + BUF_THREAD_ID_SIZE; 388 while (pkt < limit) 389 pkt = pack_hex_byte(pkt, *id++); 390 391 return pkt; 392 } 393 394 static void int_to_threadref(unsigned char *id, int value) 395 { 396 unsigned char *scan; 397 int i = 4; 398 399 scan = (unsigned char *)id; 400 while (i--) 401 *scan++ = 0; 402 put_unaligned_be32(value, scan); 403 } 404 405 static struct task_struct *getthread(struct pt_regs *regs, int tid) 406 { 407 /* 408 * Non-positive TIDs are remapped to the cpu shadow information 409 */ 410 if (tid == 0 || tid == -1) 411 tid = -atomic_read(&kgdb_active) - 2; 412 if (tid < -1 && tid > -NR_CPUS - 2) { 413 if (kgdb_info[-tid - 2].task) 414 return kgdb_info[-tid - 2].task; 415 else 416 return idle_task(-tid - 2); 417 } 418 if (tid <= 0) { 419 printk(KERN_ERR "KGDB: Internal thread select error\n"); 420 dump_stack(); 421 return NULL; 422 } 423 424 /* 425 * find_task_by_pid_ns() does not take the tasklist lock anymore 426 * but is nicely RCU locked - hence is a pretty resilient 427 * thing to use: 428 */ 429 return find_task_by_pid_ns(tid, &init_pid_ns); 430 } 431 432 433 /* 434 * Remap normal tasks to their real PID, 435 * CPU shadow threads are mapped to -CPU - 2 436 */ 437 static inline int shadow_pid(int realpid) 438 { 439 if (realpid) 440 return realpid; 441 442 return -raw_smp_processor_id() - 2; 443 } 444 445 /* 446 * All the functions that start with gdb_cmd are the various 447 * operations to implement the handlers for the gdbserial protocol 448 * where KGDB is communicating with an external debugger 449 */ 450 451 /* Handle the '?' status packets */ 452 static void gdb_cmd_status(struct kgdb_state *ks) 453 { 454 /* 455 * We know that this packet is only sent 456 * during initial connect. So to be safe, 457 * we clear out our breakpoints now in case 458 * GDB is reconnecting. 459 */ 460 dbg_remove_all_break(); 461 462 remcom_out_buffer[0] = 'S'; 463 pack_hex_byte(&remcom_out_buffer[1], ks->signo); 464 } 465 466 /* Handle the 'g' get registers request */ 467 static void gdb_cmd_getregs(struct kgdb_state *ks) 468 { 469 struct task_struct *thread; 470 void *local_debuggerinfo; 471 int i; 472 473 thread = kgdb_usethread; 474 if (!thread) { 475 thread = kgdb_info[ks->cpu].task; 476 local_debuggerinfo = kgdb_info[ks->cpu].debuggerinfo; 477 } else { 478 local_debuggerinfo = NULL; 479 for_each_online_cpu(i) { 480 /* 481 * Try to find the task on some other 482 * or possibly this node if we do not 483 * find the matching task then we try 484 * to approximate the results. 485 */ 486 if (thread == kgdb_info[i].task) 487 local_debuggerinfo = kgdb_info[i].debuggerinfo; 488 } 489 } 490 491 /* 492 * All threads that don't have debuggerinfo should be 493 * in schedule() sleeping, since all other CPUs 494 * are in kgdb_wait, and thus have debuggerinfo. 495 */ 496 if (local_debuggerinfo) { 497 pt_regs_to_gdb_regs(gdb_regs, local_debuggerinfo); 498 } else { 499 /* 500 * Pull stuff saved during switch_to; nothing 501 * else is accessible (or even particularly 502 * relevant). 503 * 504 * This should be enough for a stack trace. 505 */ 506 sleeping_thread_to_gdb_regs(gdb_regs, thread); 507 } 508 kgdb_mem2hex((char *)gdb_regs, remcom_out_buffer, NUMREGBYTES); 509 } 510 511 /* Handle the 'G' set registers request */ 512 static void gdb_cmd_setregs(struct kgdb_state *ks) 513 { 514 kgdb_hex2mem(&remcom_in_buffer[1], (char *)gdb_regs, NUMREGBYTES); 515 516 if (kgdb_usethread && kgdb_usethread != current) { 517 error_packet(remcom_out_buffer, -EINVAL); 518 } else { 519 gdb_regs_to_pt_regs(gdb_regs, ks->linux_regs); 520 strcpy(remcom_out_buffer, "OK"); 521 } 522 } 523 524 /* Handle the 'm' memory read bytes */ 525 static void gdb_cmd_memread(struct kgdb_state *ks) 526 { 527 char *ptr = &remcom_in_buffer[1]; 528 unsigned long length; 529 unsigned long addr; 530 int err; 531 532 if (kgdb_hex2long(&ptr, &addr) > 0 && *ptr++ == ',' && 533 kgdb_hex2long(&ptr, &length) > 0) { 534 err = kgdb_mem2hex((char *)addr, remcom_out_buffer, length); 535 if (err) 536 error_packet(remcom_out_buffer, err); 537 } else { 538 error_packet(remcom_out_buffer, -EINVAL); 539 } 540 } 541 542 /* Handle the 'M' memory write bytes */ 543 static void gdb_cmd_memwrite(struct kgdb_state *ks) 544 { 545 int err = write_mem_msg(0); 546 547 if (err) 548 error_packet(remcom_out_buffer, err); 549 else 550 strcpy(remcom_out_buffer, "OK"); 551 } 552 553 /* Handle the 'X' memory binary write bytes */ 554 static void gdb_cmd_binwrite(struct kgdb_state *ks) 555 { 556 int err = write_mem_msg(1); 557 558 if (err) 559 error_packet(remcom_out_buffer, err); 560 else 561 strcpy(remcom_out_buffer, "OK"); 562 } 563 564 /* Handle the 'D' or 'k', detach or kill packets */ 565 static void gdb_cmd_detachkill(struct kgdb_state *ks) 566 { 567 int error; 568 569 /* The detach case */ 570 if (remcom_in_buffer[0] == 'D') { 571 error = dbg_remove_all_break(); 572 if (error < 0) { 573 error_packet(remcom_out_buffer, error); 574 } else { 575 strcpy(remcom_out_buffer, "OK"); 576 kgdb_connected = 0; 577 } 578 put_packet(remcom_out_buffer); 579 } else { 580 /* 581 * Assume the kill case, with no exit code checking, 582 * trying to force detach the debugger: 583 */ 584 dbg_remove_all_break(); 585 kgdb_connected = 0; 586 } 587 } 588 589 /* Handle the 'R' reboot packets */ 590 static int gdb_cmd_reboot(struct kgdb_state *ks) 591 { 592 /* For now, only honor R0 */ 593 if (strcmp(remcom_in_buffer, "R0") == 0) { 594 printk(KERN_CRIT "Executing emergency reboot\n"); 595 strcpy(remcom_out_buffer, "OK"); 596 put_packet(remcom_out_buffer); 597 598 /* 599 * Execution should not return from 600 * machine_emergency_restart() 601 */ 602 machine_emergency_restart(); 603 kgdb_connected = 0; 604 605 return 1; 606 } 607 return 0; 608 } 609 610 /* Handle the 'q' query packets */ 611 static void gdb_cmd_query(struct kgdb_state *ks) 612 { 613 struct task_struct *g; 614 struct task_struct *p; 615 unsigned char thref[8]; 616 char *ptr; 617 int i; 618 int cpu; 619 int finished = 0; 620 621 switch (remcom_in_buffer[1]) { 622 case 's': 623 case 'f': 624 if (memcmp(remcom_in_buffer + 2, "ThreadInfo", 10)) { 625 error_packet(remcom_out_buffer, -EINVAL); 626 break; 627 } 628 629 i = 0; 630 remcom_out_buffer[0] = 'm'; 631 ptr = remcom_out_buffer + 1; 632 if (remcom_in_buffer[1] == 'f') { 633 /* Each cpu is a shadow thread */ 634 for_each_online_cpu(cpu) { 635 ks->thr_query = 0; 636 int_to_threadref(thref, -cpu - 2); 637 pack_threadid(ptr, thref); 638 ptr += BUF_THREAD_ID_SIZE; 639 *(ptr++) = ','; 640 i++; 641 } 642 } 643 644 do_each_thread(g, p) { 645 if (i >= ks->thr_query && !finished) { 646 int_to_threadref(thref, p->pid); 647 pack_threadid(ptr, thref); 648 ptr += BUF_THREAD_ID_SIZE; 649 *(ptr++) = ','; 650 ks->thr_query++; 651 if (ks->thr_query % KGDB_MAX_THREAD_QUERY == 0) 652 finished = 1; 653 } 654 i++; 655 } while_each_thread(g, p); 656 657 *(--ptr) = '\0'; 658 break; 659 660 case 'C': 661 /* Current thread id */ 662 strcpy(remcom_out_buffer, "QC"); 663 ks->threadid = shadow_pid(current->pid); 664 int_to_threadref(thref, ks->threadid); 665 pack_threadid(remcom_out_buffer + 2, thref); 666 break; 667 case 'T': 668 if (memcmp(remcom_in_buffer + 1, "ThreadExtraInfo,", 16)) { 669 error_packet(remcom_out_buffer, -EINVAL); 670 break; 671 } 672 ks->threadid = 0; 673 ptr = remcom_in_buffer + 17; 674 kgdb_hex2long(&ptr, &ks->threadid); 675 if (!getthread(ks->linux_regs, ks->threadid)) { 676 error_packet(remcom_out_buffer, -EINVAL); 677 break; 678 } 679 if ((int)ks->threadid > 0) { 680 kgdb_mem2hex(getthread(ks->linux_regs, 681 ks->threadid)->comm, 682 remcom_out_buffer, 16); 683 } else { 684 static char tmpstr[23 + BUF_THREAD_ID_SIZE]; 685 686 sprintf(tmpstr, "shadowCPU%d", 687 (int)(-ks->threadid - 2)); 688 kgdb_mem2hex(tmpstr, remcom_out_buffer, strlen(tmpstr)); 689 } 690 break; 691 #ifdef CONFIG_KGDB_KDB 692 case 'R': 693 if (strncmp(remcom_in_buffer, "qRcmd,", 6) == 0) { 694 int len = strlen(remcom_in_buffer + 6); 695 696 if ((len % 2) != 0) { 697 strcpy(remcom_out_buffer, "E01"); 698 break; 699 } 700 kgdb_hex2mem(remcom_in_buffer + 6, 701 remcom_out_buffer, len); 702 len = len / 2; 703 remcom_out_buffer[len++] = 0; 704 705 kdb_parse(remcom_out_buffer); 706 strcpy(remcom_out_buffer, "OK"); 707 } 708 break; 709 #endif 710 } 711 } 712 713 /* Handle the 'H' task query packets */ 714 static void gdb_cmd_task(struct kgdb_state *ks) 715 { 716 struct task_struct *thread; 717 char *ptr; 718 719 switch (remcom_in_buffer[1]) { 720 case 'g': 721 ptr = &remcom_in_buffer[2]; 722 kgdb_hex2long(&ptr, &ks->threadid); 723 thread = getthread(ks->linux_regs, ks->threadid); 724 if (!thread && ks->threadid > 0) { 725 error_packet(remcom_out_buffer, -EINVAL); 726 break; 727 } 728 kgdb_usethread = thread; 729 ks->kgdb_usethreadid = ks->threadid; 730 strcpy(remcom_out_buffer, "OK"); 731 break; 732 case 'c': 733 ptr = &remcom_in_buffer[2]; 734 kgdb_hex2long(&ptr, &ks->threadid); 735 if (!ks->threadid) { 736 kgdb_contthread = NULL; 737 } else { 738 thread = getthread(ks->linux_regs, ks->threadid); 739 if (!thread && ks->threadid > 0) { 740 error_packet(remcom_out_buffer, -EINVAL); 741 break; 742 } 743 kgdb_contthread = thread; 744 } 745 strcpy(remcom_out_buffer, "OK"); 746 break; 747 } 748 } 749 750 /* Handle the 'T' thread query packets */ 751 static void gdb_cmd_thread(struct kgdb_state *ks) 752 { 753 char *ptr = &remcom_in_buffer[1]; 754 struct task_struct *thread; 755 756 kgdb_hex2long(&ptr, &ks->threadid); 757 thread = getthread(ks->linux_regs, ks->threadid); 758 if (thread) 759 strcpy(remcom_out_buffer, "OK"); 760 else 761 error_packet(remcom_out_buffer, -EINVAL); 762 } 763 764 /* Handle the 'z' or 'Z' breakpoint remove or set packets */ 765 static void gdb_cmd_break(struct kgdb_state *ks) 766 { 767 /* 768 * Since GDB-5.3, it's been drafted that '0' is a software 769 * breakpoint, '1' is a hardware breakpoint, so let's do that. 770 */ 771 char *bpt_type = &remcom_in_buffer[1]; 772 char *ptr = &remcom_in_buffer[2]; 773 unsigned long addr; 774 unsigned long length; 775 int error = 0; 776 777 if (arch_kgdb_ops.set_hw_breakpoint && *bpt_type >= '1') { 778 /* Unsupported */ 779 if (*bpt_type > '4') 780 return; 781 } else { 782 if (*bpt_type != '0' && *bpt_type != '1') 783 /* Unsupported. */ 784 return; 785 } 786 787 /* 788 * Test if this is a hardware breakpoint, and 789 * if we support it: 790 */ 791 if (*bpt_type == '1' && !(arch_kgdb_ops.flags & KGDB_HW_BREAKPOINT)) 792 /* Unsupported. */ 793 return; 794 795 if (*(ptr++) != ',') { 796 error_packet(remcom_out_buffer, -EINVAL); 797 return; 798 } 799 if (!kgdb_hex2long(&ptr, &addr)) { 800 error_packet(remcom_out_buffer, -EINVAL); 801 return; 802 } 803 if (*(ptr++) != ',' || 804 !kgdb_hex2long(&ptr, &length)) { 805 error_packet(remcom_out_buffer, -EINVAL); 806 return; 807 } 808 809 if (remcom_in_buffer[0] == 'Z' && *bpt_type == '0') 810 error = dbg_set_sw_break(addr); 811 else if (remcom_in_buffer[0] == 'z' && *bpt_type == '0') 812 error = dbg_remove_sw_break(addr); 813 else if (remcom_in_buffer[0] == 'Z') 814 error = arch_kgdb_ops.set_hw_breakpoint(addr, 815 (int)length, *bpt_type - '0'); 816 else if (remcom_in_buffer[0] == 'z') 817 error = arch_kgdb_ops.remove_hw_breakpoint(addr, 818 (int) length, *bpt_type - '0'); 819 820 if (error == 0) 821 strcpy(remcom_out_buffer, "OK"); 822 else 823 error_packet(remcom_out_buffer, error); 824 } 825 826 /* Handle the 'C' signal / exception passing packets */ 827 static int gdb_cmd_exception_pass(struct kgdb_state *ks) 828 { 829 /* C09 == pass exception 830 * C15 == detach kgdb, pass exception 831 */ 832 if (remcom_in_buffer[1] == '0' && remcom_in_buffer[2] == '9') { 833 834 ks->pass_exception = 1; 835 remcom_in_buffer[0] = 'c'; 836 837 } else if (remcom_in_buffer[1] == '1' && remcom_in_buffer[2] == '5') { 838 839 ks->pass_exception = 1; 840 remcom_in_buffer[0] = 'D'; 841 dbg_remove_all_break(); 842 kgdb_connected = 0; 843 return 1; 844 845 } else { 846 gdbstub_msg_write("KGDB only knows signal 9 (pass)" 847 " and 15 (pass and disconnect)\n" 848 "Executing a continue without signal passing\n", 0); 849 remcom_in_buffer[0] = 'c'; 850 } 851 852 /* Indicate fall through */ 853 return -1; 854 } 855 856 /* 857 * This function performs all gdbserial command procesing 858 */ 859 int gdb_serial_stub(struct kgdb_state *ks) 860 { 861 int error = 0; 862 int tmp; 863 864 /* Clear the out buffer. */ 865 memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer)); 866 867 if (kgdb_connected) { 868 unsigned char thref[8]; 869 char *ptr; 870 871 /* Reply to host that an exception has occurred */ 872 ptr = remcom_out_buffer; 873 *ptr++ = 'T'; 874 ptr = pack_hex_byte(ptr, ks->signo); 875 ptr += strlen(strcpy(ptr, "thread:")); 876 int_to_threadref(thref, shadow_pid(current->pid)); 877 ptr = pack_threadid(ptr, thref); 878 *ptr++ = ';'; 879 put_packet(remcom_out_buffer); 880 } 881 882 kgdb_usethread = kgdb_info[ks->cpu].task; 883 ks->kgdb_usethreadid = shadow_pid(kgdb_info[ks->cpu].task->pid); 884 ks->pass_exception = 0; 885 886 while (1) { 887 error = 0; 888 889 /* Clear the out buffer. */ 890 memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer)); 891 892 get_packet(remcom_in_buffer); 893 894 switch (remcom_in_buffer[0]) { 895 case '?': /* gdbserial status */ 896 gdb_cmd_status(ks); 897 break; 898 case 'g': /* return the value of the CPU registers */ 899 gdb_cmd_getregs(ks); 900 break; 901 case 'G': /* set the value of the CPU registers - return OK */ 902 gdb_cmd_setregs(ks); 903 break; 904 case 'm': /* mAA..AA,LLLL Read LLLL bytes at address AA..AA */ 905 gdb_cmd_memread(ks); 906 break; 907 case 'M': /* MAA..AA,LLLL: Write LLLL bytes at address AA..AA */ 908 gdb_cmd_memwrite(ks); 909 break; 910 case 'X': /* XAA..AA,LLLL: Write LLLL bytes at address AA..AA */ 911 gdb_cmd_binwrite(ks); 912 break; 913 /* kill or detach. KGDB should treat this like a 914 * continue. 915 */ 916 case 'D': /* Debugger detach */ 917 case 'k': /* Debugger detach via kill */ 918 gdb_cmd_detachkill(ks); 919 goto default_handle; 920 case 'R': /* Reboot */ 921 if (gdb_cmd_reboot(ks)) 922 goto default_handle; 923 break; 924 case 'q': /* query command */ 925 gdb_cmd_query(ks); 926 break; 927 case 'H': /* task related */ 928 gdb_cmd_task(ks); 929 break; 930 case 'T': /* Query thread status */ 931 gdb_cmd_thread(ks); 932 break; 933 case 'z': /* Break point remove */ 934 case 'Z': /* Break point set */ 935 gdb_cmd_break(ks); 936 break; 937 #ifdef CONFIG_KGDB_KDB 938 case '3': /* Escape into back into kdb */ 939 if (remcom_in_buffer[1] == '\0') { 940 gdb_cmd_detachkill(ks); 941 return DBG_PASS_EVENT; 942 } 943 #endif 944 case 'C': /* Exception passing */ 945 tmp = gdb_cmd_exception_pass(ks); 946 if (tmp > 0) 947 goto default_handle; 948 if (tmp == 0) 949 break; 950 /* Fall through on tmp < 0 */ 951 case 'c': /* Continue packet */ 952 case 's': /* Single step packet */ 953 if (kgdb_contthread && kgdb_contthread != current) { 954 /* Can't switch threads in kgdb */ 955 error_packet(remcom_out_buffer, -EINVAL); 956 break; 957 } 958 dbg_activate_sw_breakpoints(); 959 /* Fall through to default processing */ 960 default: 961 default_handle: 962 error = kgdb_arch_handle_exception(ks->ex_vector, 963 ks->signo, 964 ks->err_code, 965 remcom_in_buffer, 966 remcom_out_buffer, 967 ks->linux_regs); 968 /* 969 * Leave cmd processing on error, detach, 970 * kill, continue, or single step. 971 */ 972 if (error >= 0 || remcom_in_buffer[0] == 'D' || 973 remcom_in_buffer[0] == 'k') { 974 error = 0; 975 goto kgdb_exit; 976 } 977 978 } 979 980 /* reply to the request */ 981 put_packet(remcom_out_buffer); 982 } 983 984 kgdb_exit: 985 if (ks->pass_exception) 986 error = 1; 987 return error; 988 } 989 990 int gdbstub_state(struct kgdb_state *ks, char *cmd) 991 { 992 int error; 993 994 switch (cmd[0]) { 995 case 'e': 996 error = kgdb_arch_handle_exception(ks->ex_vector, 997 ks->signo, 998 ks->err_code, 999 remcom_in_buffer, 1000 remcom_out_buffer, 1001 ks->linux_regs); 1002 return error; 1003 case 's': 1004 case 'c': 1005 strcpy(remcom_in_buffer, cmd); 1006 return 0; 1007 case '?': 1008 gdb_cmd_status(ks); 1009 break; 1010 case '\0': 1011 strcpy(remcom_out_buffer, ""); 1012 break; 1013 } 1014 dbg_io_ops->write_char('+'); 1015 put_packet(remcom_out_buffer); 1016 return 0; 1017 } 1018