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