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 /* 'O'utput */ 205 gdbmsgbuf[0] = 'O'; 206 207 /* Fill and send buffers... */ 208 while (len > 0) { 209 bufptr = gdbmsgbuf + 1; 210 211 /* Calculate how many this time */ 212 if ((len << 1) > (BUFMAX - 2)) 213 wcount = (BUFMAX - 2) >> 1; 214 else 215 wcount = len; 216 217 /* Pack in hex chars */ 218 for (i = 0; i < wcount; i++) 219 bufptr = pack_hex_byte(bufptr, s[i]); 220 *bufptr = '\0'; 221 222 /* Move up */ 223 s += wcount; 224 len -= wcount; 225 226 /* Write packet */ 227 put_packet(gdbmsgbuf); 228 } 229 } 230 231 /* 232 * Convert the memory pointed to by mem into hex, placing result in 233 * buf. Return a pointer to the last char put in buf (null). May 234 * return an error. 235 */ 236 int kgdb_mem2hex(char *mem, char *buf, int count) 237 { 238 char *tmp; 239 int err; 240 241 /* 242 * We use the upper half of buf as an intermediate buffer for the 243 * raw memory copy. Hex conversion will work against this one. 244 */ 245 tmp = buf + count; 246 247 err = probe_kernel_read(tmp, mem, count); 248 if (!err) { 249 while (count > 0) { 250 buf = pack_hex_byte(buf, *tmp); 251 tmp++; 252 count--; 253 } 254 255 *buf = 0; 256 } 257 258 return err; 259 } 260 261 /* 262 * Convert the hex array pointed to by buf into binary to be placed in 263 * mem. Return a pointer to the character AFTER the last byte 264 * written. May return an error. 265 */ 266 int kgdb_hex2mem(char *buf, char *mem, int count) 267 { 268 char *tmp_raw; 269 char *tmp_hex; 270 271 /* 272 * We use the upper half of buf as an intermediate buffer for the 273 * raw memory that is converted from hex. 274 */ 275 tmp_raw = buf + count * 2; 276 277 tmp_hex = tmp_raw - 1; 278 while (tmp_hex >= buf) { 279 tmp_raw--; 280 *tmp_raw = hex(*tmp_hex--); 281 *tmp_raw |= hex(*tmp_hex--) << 4; 282 } 283 284 return probe_kernel_write(mem, tmp_raw, count); 285 } 286 287 /* 288 * While we find nice hex chars, build a long_val. 289 * Return number of chars processed. 290 */ 291 int kgdb_hex2long(char **ptr, unsigned long *long_val) 292 { 293 int hex_val; 294 int num = 0; 295 int negate = 0; 296 297 *long_val = 0; 298 299 if (**ptr == '-') { 300 negate = 1; 301 (*ptr)++; 302 } 303 while (**ptr) { 304 hex_val = hex(**ptr); 305 if (hex_val < 0) 306 break; 307 308 *long_val = (*long_val << 4) | hex_val; 309 num++; 310 (*ptr)++; 311 } 312 313 if (negate) 314 *long_val = -*long_val; 315 316 return num; 317 } 318 319 /* 320 * Copy the binary array pointed to by buf into mem. Fix $, #, and 321 * 0x7d escaped with 0x7d. Return -EFAULT on failure or 0 on success. 322 * The input buf is overwitten with the result to write to mem. 323 */ 324 static int kgdb_ebin2mem(char *buf, char *mem, int count) 325 { 326 int size = 0; 327 char *c = buf; 328 329 while (count-- > 0) { 330 c[size] = *buf++; 331 if (c[size] == 0x7d) 332 c[size] = *buf++ ^ 0x20; 333 size++; 334 } 335 336 return probe_kernel_write(mem, c, size); 337 } 338 339 /* Write memory due to an 'M' or 'X' packet. */ 340 static int write_mem_msg(int binary) 341 { 342 char *ptr = &remcom_in_buffer[1]; 343 unsigned long addr; 344 unsigned long length; 345 int err; 346 347 if (kgdb_hex2long(&ptr, &addr) > 0 && *(ptr++) == ',' && 348 kgdb_hex2long(&ptr, &length) > 0 && *(ptr++) == ':') { 349 if (binary) 350 err = kgdb_ebin2mem(ptr, (char *)addr, length); 351 else 352 err = kgdb_hex2mem(ptr, (char *)addr, length); 353 if (err) 354 return err; 355 if (CACHE_FLUSH_IS_SAFE) 356 flush_icache_range(addr, addr + length); 357 return 0; 358 } 359 360 return -EINVAL; 361 } 362 363 static void error_packet(char *pkt, int error) 364 { 365 error = -error; 366 pkt[0] = 'E'; 367 pkt[1] = hex_asc[(error / 10)]; 368 pkt[2] = hex_asc[(error % 10)]; 369 pkt[3] = '\0'; 370 } 371 372 /* 373 * Thread ID accessors. We represent a flat TID space to GDB, where 374 * the per CPU idle threads (which under Linux all have PID 0) are 375 * remapped to negative TIDs. 376 */ 377 378 #define BUF_THREAD_ID_SIZE 16 379 380 static char *pack_threadid(char *pkt, unsigned char *id) 381 { 382 char *limit; 383 384 limit = pkt + BUF_THREAD_ID_SIZE; 385 while (pkt < limit) 386 pkt = pack_hex_byte(pkt, *id++); 387 388 return pkt; 389 } 390 391 static void int_to_threadref(unsigned char *id, int value) 392 { 393 unsigned char *scan; 394 int i = 4; 395 396 scan = (unsigned char *)id; 397 while (i--) 398 *scan++ = 0; 399 put_unaligned_be32(value, scan); 400 } 401 402 static struct task_struct *getthread(struct pt_regs *regs, int tid) 403 { 404 /* 405 * Non-positive TIDs are remapped to the cpu shadow information 406 */ 407 if (tid == 0 || tid == -1) 408 tid = -atomic_read(&kgdb_active) - 2; 409 if (tid < -1 && tid > -NR_CPUS - 2) { 410 if (kgdb_info[-tid - 2].task) 411 return kgdb_info[-tid - 2].task; 412 else 413 return idle_task(-tid - 2); 414 } 415 if (tid <= 0) { 416 printk(KERN_ERR "KGDB: Internal thread select error\n"); 417 dump_stack(); 418 return NULL; 419 } 420 421 /* 422 * find_task_by_pid_ns() does not take the tasklist lock anymore 423 * but is nicely RCU locked - hence is a pretty resilient 424 * thing to use: 425 */ 426 return find_task_by_pid_ns(tid, &init_pid_ns); 427 } 428 429 430 /* 431 * Remap normal tasks to their real PID, 432 * CPU shadow threads are mapped to -CPU - 2 433 */ 434 static inline int shadow_pid(int realpid) 435 { 436 if (realpid) 437 return realpid; 438 439 return -raw_smp_processor_id() - 2; 440 } 441 442 /* 443 * All the functions that start with gdb_cmd are the various 444 * operations to implement the handlers for the gdbserial protocol 445 * where KGDB is communicating with an external debugger 446 */ 447 448 /* Handle the '?' status packets */ 449 static void gdb_cmd_status(struct kgdb_state *ks) 450 { 451 /* 452 * We know that this packet is only sent 453 * during initial connect. So to be safe, 454 * we clear out our breakpoints now in case 455 * GDB is reconnecting. 456 */ 457 dbg_remove_all_break(); 458 459 remcom_out_buffer[0] = 'S'; 460 pack_hex_byte(&remcom_out_buffer[1], ks->signo); 461 } 462 463 /* Handle the 'g' get registers request */ 464 static void gdb_cmd_getregs(struct kgdb_state *ks) 465 { 466 struct task_struct *thread; 467 void *local_debuggerinfo; 468 int i; 469 470 thread = kgdb_usethread; 471 if (!thread) { 472 thread = kgdb_info[ks->cpu].task; 473 local_debuggerinfo = kgdb_info[ks->cpu].debuggerinfo; 474 } else { 475 local_debuggerinfo = NULL; 476 for_each_online_cpu(i) { 477 /* 478 * Try to find the task on some other 479 * or possibly this node if we do not 480 * find the matching task then we try 481 * to approximate the results. 482 */ 483 if (thread == kgdb_info[i].task) 484 local_debuggerinfo = kgdb_info[i].debuggerinfo; 485 } 486 } 487 488 /* 489 * All threads that don't have debuggerinfo should be 490 * in schedule() sleeping, since all other CPUs 491 * are in kgdb_wait, and thus have debuggerinfo. 492 */ 493 if (local_debuggerinfo) { 494 pt_regs_to_gdb_regs(gdb_regs, local_debuggerinfo); 495 } else { 496 /* 497 * Pull stuff saved during switch_to; nothing 498 * else is accessible (or even particularly 499 * relevant). 500 * 501 * This should be enough for a stack trace. 502 */ 503 sleeping_thread_to_gdb_regs(gdb_regs, thread); 504 } 505 kgdb_mem2hex((char *)gdb_regs, remcom_out_buffer, NUMREGBYTES); 506 } 507 508 /* Handle the 'G' set registers request */ 509 static void gdb_cmd_setregs(struct kgdb_state *ks) 510 { 511 kgdb_hex2mem(&remcom_in_buffer[1], (char *)gdb_regs, NUMREGBYTES); 512 513 if (kgdb_usethread && kgdb_usethread != current) { 514 error_packet(remcom_out_buffer, -EINVAL); 515 } else { 516 gdb_regs_to_pt_regs(gdb_regs, ks->linux_regs); 517 strcpy(remcom_out_buffer, "OK"); 518 } 519 } 520 521 /* Handle the 'm' memory read bytes */ 522 static void gdb_cmd_memread(struct kgdb_state *ks) 523 { 524 char *ptr = &remcom_in_buffer[1]; 525 unsigned long length; 526 unsigned long addr; 527 int err; 528 529 if (kgdb_hex2long(&ptr, &addr) > 0 && *ptr++ == ',' && 530 kgdb_hex2long(&ptr, &length) > 0) { 531 err = kgdb_mem2hex((char *)addr, remcom_out_buffer, length); 532 if (err) 533 error_packet(remcom_out_buffer, err); 534 } else { 535 error_packet(remcom_out_buffer, -EINVAL); 536 } 537 } 538 539 /* Handle the 'M' memory write bytes */ 540 static void gdb_cmd_memwrite(struct kgdb_state *ks) 541 { 542 int err = write_mem_msg(0); 543 544 if (err) 545 error_packet(remcom_out_buffer, err); 546 else 547 strcpy(remcom_out_buffer, "OK"); 548 } 549 550 /* Handle the 'X' memory binary write bytes */ 551 static void gdb_cmd_binwrite(struct kgdb_state *ks) 552 { 553 int err = write_mem_msg(1); 554 555 if (err) 556 error_packet(remcom_out_buffer, err); 557 else 558 strcpy(remcom_out_buffer, "OK"); 559 } 560 561 /* Handle the 'D' or 'k', detach or kill packets */ 562 static void gdb_cmd_detachkill(struct kgdb_state *ks) 563 { 564 int error; 565 566 /* The detach case */ 567 if (remcom_in_buffer[0] == 'D') { 568 error = dbg_remove_all_break(); 569 if (error < 0) { 570 error_packet(remcom_out_buffer, error); 571 } else { 572 strcpy(remcom_out_buffer, "OK"); 573 kgdb_connected = 0; 574 } 575 put_packet(remcom_out_buffer); 576 } else { 577 /* 578 * Assume the kill case, with no exit code checking, 579 * trying to force detach the debugger: 580 */ 581 dbg_remove_all_break(); 582 kgdb_connected = 0; 583 } 584 } 585 586 /* Handle the 'R' reboot packets */ 587 static int gdb_cmd_reboot(struct kgdb_state *ks) 588 { 589 /* For now, only honor R0 */ 590 if (strcmp(remcom_in_buffer, "R0") == 0) { 591 printk(KERN_CRIT "Executing emergency reboot\n"); 592 strcpy(remcom_out_buffer, "OK"); 593 put_packet(remcom_out_buffer); 594 595 /* 596 * Execution should not return from 597 * machine_emergency_restart() 598 */ 599 machine_emergency_restart(); 600 kgdb_connected = 0; 601 602 return 1; 603 } 604 return 0; 605 } 606 607 /* Handle the 'q' query packets */ 608 static void gdb_cmd_query(struct kgdb_state *ks) 609 { 610 struct task_struct *g; 611 struct task_struct *p; 612 unsigned char thref[8]; 613 char *ptr; 614 int i; 615 int cpu; 616 int finished = 0; 617 618 switch (remcom_in_buffer[1]) { 619 case 's': 620 case 'f': 621 if (memcmp(remcom_in_buffer + 2, "ThreadInfo", 10)) { 622 error_packet(remcom_out_buffer, -EINVAL); 623 break; 624 } 625 626 i = 0; 627 remcom_out_buffer[0] = 'm'; 628 ptr = remcom_out_buffer + 1; 629 if (remcom_in_buffer[1] == 'f') { 630 /* Each cpu is a shadow thread */ 631 for_each_online_cpu(cpu) { 632 ks->thr_query = 0; 633 int_to_threadref(thref, -cpu - 2); 634 pack_threadid(ptr, thref); 635 ptr += BUF_THREAD_ID_SIZE; 636 *(ptr++) = ','; 637 i++; 638 } 639 } 640 641 do_each_thread(g, p) { 642 if (i >= ks->thr_query && !finished) { 643 int_to_threadref(thref, p->pid); 644 pack_threadid(ptr, thref); 645 ptr += BUF_THREAD_ID_SIZE; 646 *(ptr++) = ','; 647 ks->thr_query++; 648 if (ks->thr_query % KGDB_MAX_THREAD_QUERY == 0) 649 finished = 1; 650 } 651 i++; 652 } while_each_thread(g, p); 653 654 *(--ptr) = '\0'; 655 break; 656 657 case 'C': 658 /* Current thread id */ 659 strcpy(remcom_out_buffer, "QC"); 660 ks->threadid = shadow_pid(current->pid); 661 int_to_threadref(thref, ks->threadid); 662 pack_threadid(remcom_out_buffer + 2, thref); 663 break; 664 case 'T': 665 if (memcmp(remcom_in_buffer + 1, "ThreadExtraInfo,", 16)) { 666 error_packet(remcom_out_buffer, -EINVAL); 667 break; 668 } 669 ks->threadid = 0; 670 ptr = remcom_in_buffer + 17; 671 kgdb_hex2long(&ptr, &ks->threadid); 672 if (!getthread(ks->linux_regs, ks->threadid)) { 673 error_packet(remcom_out_buffer, -EINVAL); 674 break; 675 } 676 if ((int)ks->threadid > 0) { 677 kgdb_mem2hex(getthread(ks->linux_regs, 678 ks->threadid)->comm, 679 remcom_out_buffer, 16); 680 } else { 681 static char tmpstr[23 + BUF_THREAD_ID_SIZE]; 682 683 sprintf(tmpstr, "shadowCPU%d", 684 (int)(-ks->threadid - 2)); 685 kgdb_mem2hex(tmpstr, remcom_out_buffer, strlen(tmpstr)); 686 } 687 break; 688 } 689 } 690 691 /* Handle the 'H' task query packets */ 692 static void gdb_cmd_task(struct kgdb_state *ks) 693 { 694 struct task_struct *thread; 695 char *ptr; 696 697 switch (remcom_in_buffer[1]) { 698 case 'g': 699 ptr = &remcom_in_buffer[2]; 700 kgdb_hex2long(&ptr, &ks->threadid); 701 thread = getthread(ks->linux_regs, ks->threadid); 702 if (!thread && ks->threadid > 0) { 703 error_packet(remcom_out_buffer, -EINVAL); 704 break; 705 } 706 kgdb_usethread = thread; 707 ks->kgdb_usethreadid = ks->threadid; 708 strcpy(remcom_out_buffer, "OK"); 709 break; 710 case 'c': 711 ptr = &remcom_in_buffer[2]; 712 kgdb_hex2long(&ptr, &ks->threadid); 713 if (!ks->threadid) { 714 kgdb_contthread = NULL; 715 } else { 716 thread = getthread(ks->linux_regs, ks->threadid); 717 if (!thread && ks->threadid > 0) { 718 error_packet(remcom_out_buffer, -EINVAL); 719 break; 720 } 721 kgdb_contthread = thread; 722 } 723 strcpy(remcom_out_buffer, "OK"); 724 break; 725 } 726 } 727 728 /* Handle the 'T' thread query packets */ 729 static void gdb_cmd_thread(struct kgdb_state *ks) 730 { 731 char *ptr = &remcom_in_buffer[1]; 732 struct task_struct *thread; 733 734 kgdb_hex2long(&ptr, &ks->threadid); 735 thread = getthread(ks->linux_regs, ks->threadid); 736 if (thread) 737 strcpy(remcom_out_buffer, "OK"); 738 else 739 error_packet(remcom_out_buffer, -EINVAL); 740 } 741 742 /* Handle the 'z' or 'Z' breakpoint remove or set packets */ 743 static void gdb_cmd_break(struct kgdb_state *ks) 744 { 745 /* 746 * Since GDB-5.3, it's been drafted that '0' is a software 747 * breakpoint, '1' is a hardware breakpoint, so let's do that. 748 */ 749 char *bpt_type = &remcom_in_buffer[1]; 750 char *ptr = &remcom_in_buffer[2]; 751 unsigned long addr; 752 unsigned long length; 753 int error = 0; 754 755 if (arch_kgdb_ops.set_hw_breakpoint && *bpt_type >= '1') { 756 /* Unsupported */ 757 if (*bpt_type > '4') 758 return; 759 } else { 760 if (*bpt_type != '0' && *bpt_type != '1') 761 /* Unsupported. */ 762 return; 763 } 764 765 /* 766 * Test if this is a hardware breakpoint, and 767 * if we support it: 768 */ 769 if (*bpt_type == '1' && !(arch_kgdb_ops.flags & KGDB_HW_BREAKPOINT)) 770 /* Unsupported. */ 771 return; 772 773 if (*(ptr++) != ',') { 774 error_packet(remcom_out_buffer, -EINVAL); 775 return; 776 } 777 if (!kgdb_hex2long(&ptr, &addr)) { 778 error_packet(remcom_out_buffer, -EINVAL); 779 return; 780 } 781 if (*(ptr++) != ',' || 782 !kgdb_hex2long(&ptr, &length)) { 783 error_packet(remcom_out_buffer, -EINVAL); 784 return; 785 } 786 787 if (remcom_in_buffer[0] == 'Z' && *bpt_type == '0') 788 error = dbg_set_sw_break(addr); 789 else if (remcom_in_buffer[0] == 'z' && *bpt_type == '0') 790 error = dbg_remove_sw_break(addr); 791 else if (remcom_in_buffer[0] == 'Z') 792 error = arch_kgdb_ops.set_hw_breakpoint(addr, 793 (int)length, *bpt_type - '0'); 794 else if (remcom_in_buffer[0] == 'z') 795 error = arch_kgdb_ops.remove_hw_breakpoint(addr, 796 (int) length, *bpt_type - '0'); 797 798 if (error == 0) 799 strcpy(remcom_out_buffer, "OK"); 800 else 801 error_packet(remcom_out_buffer, error); 802 } 803 804 /* Handle the 'C' signal / exception passing packets */ 805 static int gdb_cmd_exception_pass(struct kgdb_state *ks) 806 { 807 /* C09 == pass exception 808 * C15 == detach kgdb, pass exception 809 */ 810 if (remcom_in_buffer[1] == '0' && remcom_in_buffer[2] == '9') { 811 812 ks->pass_exception = 1; 813 remcom_in_buffer[0] = 'c'; 814 815 } else if (remcom_in_buffer[1] == '1' && remcom_in_buffer[2] == '5') { 816 817 ks->pass_exception = 1; 818 remcom_in_buffer[0] = 'D'; 819 dbg_remove_all_break(); 820 kgdb_connected = 0; 821 return 1; 822 823 } else { 824 gdbstub_msg_write("KGDB only knows signal 9 (pass)" 825 " and 15 (pass and disconnect)\n" 826 "Executing a continue without signal passing\n", 0); 827 remcom_in_buffer[0] = 'c'; 828 } 829 830 /* Indicate fall through */ 831 return -1; 832 } 833 834 /* 835 * This function performs all gdbserial command procesing 836 */ 837 int gdb_serial_stub(struct kgdb_state *ks) 838 { 839 int error = 0; 840 int tmp; 841 842 /* Clear the out buffer. */ 843 memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer)); 844 845 if (kgdb_connected) { 846 unsigned char thref[8]; 847 char *ptr; 848 849 /* Reply to host that an exception has occurred */ 850 ptr = remcom_out_buffer; 851 *ptr++ = 'T'; 852 ptr = pack_hex_byte(ptr, ks->signo); 853 ptr += strlen(strcpy(ptr, "thread:")); 854 int_to_threadref(thref, shadow_pid(current->pid)); 855 ptr = pack_threadid(ptr, thref); 856 *ptr++ = ';'; 857 put_packet(remcom_out_buffer); 858 } 859 860 kgdb_usethread = kgdb_info[ks->cpu].task; 861 ks->kgdb_usethreadid = shadow_pid(kgdb_info[ks->cpu].task->pid); 862 ks->pass_exception = 0; 863 864 while (1) { 865 error = 0; 866 867 /* Clear the out buffer. */ 868 memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer)); 869 870 get_packet(remcom_in_buffer); 871 872 switch (remcom_in_buffer[0]) { 873 case '?': /* gdbserial status */ 874 gdb_cmd_status(ks); 875 break; 876 case 'g': /* return the value of the CPU registers */ 877 gdb_cmd_getregs(ks); 878 break; 879 case 'G': /* set the value of the CPU registers - return OK */ 880 gdb_cmd_setregs(ks); 881 break; 882 case 'm': /* mAA..AA,LLLL Read LLLL bytes at address AA..AA */ 883 gdb_cmd_memread(ks); 884 break; 885 case 'M': /* MAA..AA,LLLL: Write LLLL bytes at address AA..AA */ 886 gdb_cmd_memwrite(ks); 887 break; 888 case 'X': /* XAA..AA,LLLL: Write LLLL bytes at address AA..AA */ 889 gdb_cmd_binwrite(ks); 890 break; 891 /* kill or detach. KGDB should treat this like a 892 * continue. 893 */ 894 case 'D': /* Debugger detach */ 895 case 'k': /* Debugger detach via kill */ 896 gdb_cmd_detachkill(ks); 897 goto default_handle; 898 case 'R': /* Reboot */ 899 if (gdb_cmd_reboot(ks)) 900 goto default_handle; 901 break; 902 case 'q': /* query command */ 903 gdb_cmd_query(ks); 904 break; 905 case 'H': /* task related */ 906 gdb_cmd_task(ks); 907 break; 908 case 'T': /* Query thread status */ 909 gdb_cmd_thread(ks); 910 break; 911 case 'z': /* Break point remove */ 912 case 'Z': /* Break point set */ 913 gdb_cmd_break(ks); 914 break; 915 #ifdef CONFIG_KGDB_KDB 916 case '3': /* Escape into back into kdb */ 917 if (remcom_in_buffer[1] == '\0') { 918 gdb_cmd_detachkill(ks); 919 return DBG_PASS_EVENT; 920 } 921 #endif 922 case 'C': /* Exception passing */ 923 tmp = gdb_cmd_exception_pass(ks); 924 if (tmp > 0) 925 goto default_handle; 926 if (tmp == 0) 927 break; 928 /* Fall through on tmp < 0 */ 929 case 'c': /* Continue packet */ 930 case 's': /* Single step packet */ 931 if (kgdb_contthread && kgdb_contthread != current) { 932 /* Can't switch threads in kgdb */ 933 error_packet(remcom_out_buffer, -EINVAL); 934 break; 935 } 936 dbg_activate_sw_breakpoints(); 937 /* Fall through to default processing */ 938 default: 939 default_handle: 940 error = kgdb_arch_handle_exception(ks->ex_vector, 941 ks->signo, 942 ks->err_code, 943 remcom_in_buffer, 944 remcom_out_buffer, 945 ks->linux_regs); 946 /* 947 * Leave cmd processing on error, detach, 948 * kill, continue, or single step. 949 */ 950 if (error >= 0 || remcom_in_buffer[0] == 'D' || 951 remcom_in_buffer[0] == 'k') { 952 error = 0; 953 goto kgdb_exit; 954 } 955 956 } 957 958 /* reply to the request */ 959 put_packet(remcom_out_buffer); 960 } 961 962 kgdb_exit: 963 if (ks->pass_exception) 964 error = 1; 965 return error; 966 } 967 968 int gdbstub_state(struct kgdb_state *ks, char *cmd) 969 { 970 int error; 971 972 switch (cmd[0]) { 973 case 'e': 974 error = kgdb_arch_handle_exception(ks->ex_vector, 975 ks->signo, 976 ks->err_code, 977 remcom_in_buffer, 978 remcom_out_buffer, 979 ks->linux_regs); 980 return error; 981 case 's': 982 case 'c': 983 strcpy(remcom_in_buffer, cmd); 984 return 0; 985 case '?': 986 gdb_cmd_status(ks); 987 break; 988 case '\0': 989 strcpy(remcom_out_buffer, ""); 990 break; 991 } 992 dbg_io_ops->write_char('+'); 993 put_packet(remcom_out_buffer); 994 return 0; 995 } 996