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@ucw.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/sched/signal.h> 33 #include <linux/kgdb.h> 34 #include <linux/kdb.h> 35 #include <linux/serial_core.h> 36 #include <linux/reboot.h> 37 #include <linux/uaccess.h> 38 #include <asm/cacheflush.h> 39 #include <asm/unaligned.h> 40 #include "debug_core.h" 41 42 #define KGDB_MAX_THREAD_QUERY 17 43 44 /* Our I/O buffers. */ 45 static char remcom_in_buffer[BUFMAX]; 46 static char remcom_out_buffer[BUFMAX]; 47 static int gdbstub_use_prev_in_buf; 48 static int gdbstub_prev_in_buf_pos; 49 50 /* Storage for the registers, in GDB format. */ 51 static unsigned long gdb_regs[(NUMREGBYTES + 52 sizeof(unsigned long) - 1) / 53 sizeof(unsigned long)]; 54 55 /* 56 * GDB remote protocol parser: 57 */ 58 59 #ifdef CONFIG_KGDB_KDB 60 static int gdbstub_read_wait(void) 61 { 62 int ret = -1; 63 int i; 64 65 if (unlikely(gdbstub_use_prev_in_buf)) { 66 if (gdbstub_prev_in_buf_pos < gdbstub_use_prev_in_buf) 67 return remcom_in_buffer[gdbstub_prev_in_buf_pos++]; 68 else 69 gdbstub_use_prev_in_buf = 0; 70 } 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 } 123 124 if (ch == '#') { 125 xmitcsum = hex_to_bin(gdbstub_read_wait()) << 4; 126 xmitcsum += hex_to_bin(gdbstub_read_wait()); 127 128 if (checksum != xmitcsum) 129 /* failed checksum */ 130 dbg_io_ops->write_char('-'); 131 else 132 /* successful transfer */ 133 dbg_io_ops->write_char('+'); 134 if (dbg_io_ops->flush) 135 dbg_io_ops->flush(); 136 } 137 buffer[count] = 0; 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 = hex_byte_pack(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 char *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 = copy_from_kernel_nofault(tmp, mem, count); 251 if (err) 252 return NULL; 253 while (count > 0) { 254 buf = hex_byte_pack(buf, *tmp); 255 tmp++; 256 count--; 257 } 258 *buf = 0; 259 260 return buf; 261 } 262 263 /* 264 * Convert the hex array pointed to by buf into binary to be placed in 265 * mem. Return a pointer to the character AFTER the last byte 266 * written. May return an error. 267 */ 268 int kgdb_hex2mem(char *buf, char *mem, int count) 269 { 270 char *tmp_raw; 271 char *tmp_hex; 272 273 /* 274 * We use the upper half of buf as an intermediate buffer for the 275 * raw memory that is converted from hex. 276 */ 277 tmp_raw = buf + count * 2; 278 279 tmp_hex = tmp_raw - 1; 280 while (tmp_hex >= buf) { 281 tmp_raw--; 282 *tmp_raw = hex_to_bin(*tmp_hex--); 283 *tmp_raw |= hex_to_bin(*tmp_hex--) << 4; 284 } 285 286 return copy_to_kernel_nofault(mem, tmp_raw, count); 287 } 288 289 /* 290 * While we find nice hex chars, build a long_val. 291 * Return number of chars processed. 292 */ 293 int kgdb_hex2long(char **ptr, unsigned long *long_val) 294 { 295 int hex_val; 296 int num = 0; 297 int negate = 0; 298 299 *long_val = 0; 300 301 if (**ptr == '-') { 302 negate = 1; 303 (*ptr)++; 304 } 305 while (**ptr) { 306 hex_val = hex_to_bin(**ptr); 307 if (hex_val < 0) 308 break; 309 310 *long_val = (*long_val << 4) | hex_val; 311 num++; 312 (*ptr)++; 313 } 314 315 if (negate) 316 *long_val = -*long_val; 317 318 return num; 319 } 320 321 /* 322 * Copy the binary array pointed to by buf into mem. Fix $, #, and 323 * 0x7d escaped with 0x7d. Return -EFAULT on failure or 0 on success. 324 * The input buf is overwitten with the result to write to mem. 325 */ 326 static int kgdb_ebin2mem(char *buf, char *mem, int count) 327 { 328 int size = 0; 329 char *c = buf; 330 331 while (count-- > 0) { 332 c[size] = *buf++; 333 if (c[size] == 0x7d) 334 c[size] = *buf++ ^ 0x20; 335 size++; 336 } 337 338 return copy_to_kernel_nofault(mem, c, size); 339 } 340 341 #if DBG_MAX_REG_NUM > 0 342 void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs) 343 { 344 int i; 345 int idx = 0; 346 char *ptr = (char *)gdb_regs; 347 348 for (i = 0; i < DBG_MAX_REG_NUM; i++) { 349 dbg_get_reg(i, ptr + idx, regs); 350 idx += dbg_reg_def[i].size; 351 } 352 } 353 354 void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs) 355 { 356 int i; 357 int idx = 0; 358 char *ptr = (char *)gdb_regs; 359 360 for (i = 0; i < DBG_MAX_REG_NUM; i++) { 361 dbg_set_reg(i, ptr + idx, regs); 362 idx += dbg_reg_def[i].size; 363 } 364 } 365 #endif /* DBG_MAX_REG_NUM > 0 */ 366 367 /* Write memory due to an 'M' or 'X' packet. */ 368 static int write_mem_msg(int binary) 369 { 370 char *ptr = &remcom_in_buffer[1]; 371 unsigned long addr; 372 unsigned long length; 373 int err; 374 375 if (kgdb_hex2long(&ptr, &addr) > 0 && *(ptr++) == ',' && 376 kgdb_hex2long(&ptr, &length) > 0 && *(ptr++) == ':') { 377 if (binary) 378 err = kgdb_ebin2mem(ptr, (char *)addr, length); 379 else 380 err = kgdb_hex2mem(ptr, (char *)addr, length); 381 if (err) 382 return err; 383 if (CACHE_FLUSH_IS_SAFE) 384 flush_icache_range(addr, addr + length); 385 return 0; 386 } 387 388 return -EINVAL; 389 } 390 391 static void error_packet(char *pkt, int error) 392 { 393 error = -error; 394 pkt[0] = 'E'; 395 pkt[1] = hex_asc[(error / 10)]; 396 pkt[2] = hex_asc[(error % 10)]; 397 pkt[3] = '\0'; 398 } 399 400 /* 401 * Thread ID accessors. We represent a flat TID space to GDB, where 402 * the per CPU idle threads (which under Linux all have PID 0) are 403 * remapped to negative TIDs. 404 */ 405 406 #define BUF_THREAD_ID_SIZE 8 407 408 static char *pack_threadid(char *pkt, unsigned char *id) 409 { 410 unsigned char *limit; 411 int lzero = 1; 412 413 limit = id + (BUF_THREAD_ID_SIZE / 2); 414 while (id < limit) { 415 if (!lzero || *id != 0) { 416 pkt = hex_byte_pack(pkt, *id); 417 lzero = 0; 418 } 419 id++; 420 } 421 422 if (lzero) 423 pkt = hex_byte_pack(pkt, 0); 424 425 return pkt; 426 } 427 428 static void int_to_threadref(unsigned char *id, int value) 429 { 430 put_unaligned_be32(value, id); 431 } 432 433 static struct task_struct *getthread(struct pt_regs *regs, int tid) 434 { 435 /* 436 * Non-positive TIDs are remapped to the cpu shadow information 437 */ 438 if (tid == 0 || tid == -1) 439 tid = -atomic_read(&kgdb_active) - 2; 440 if (tid < -1 && tid > -NR_CPUS - 2) { 441 if (kgdb_info[-tid - 2].task) 442 return kgdb_info[-tid - 2].task; 443 else 444 return idle_task(-tid - 2); 445 } 446 if (tid <= 0) { 447 printk(KERN_ERR "KGDB: Internal thread select error\n"); 448 dump_stack(); 449 return NULL; 450 } 451 452 /* 453 * find_task_by_pid_ns() does not take the tasklist lock anymore 454 * but is nicely RCU locked - hence is a pretty resilient 455 * thing to use: 456 */ 457 return find_task_by_pid_ns(tid, &init_pid_ns); 458 } 459 460 461 /* 462 * Remap normal tasks to their real PID, 463 * CPU shadow threads are mapped to -CPU - 2 464 */ 465 static inline int shadow_pid(int realpid) 466 { 467 if (realpid) 468 return realpid; 469 470 return -raw_smp_processor_id() - 2; 471 } 472 473 /* 474 * All the functions that start with gdb_cmd are the various 475 * operations to implement the handlers for the gdbserial protocol 476 * where KGDB is communicating with an external debugger 477 */ 478 479 /* Handle the '?' status packets */ 480 static void gdb_cmd_status(struct kgdb_state *ks) 481 { 482 /* 483 * We know that this packet is only sent 484 * during initial connect. So to be safe, 485 * we clear out our breakpoints now in case 486 * GDB is reconnecting. 487 */ 488 dbg_remove_all_break(); 489 490 remcom_out_buffer[0] = 'S'; 491 hex_byte_pack(&remcom_out_buffer[1], ks->signo); 492 } 493 494 static void gdb_get_regs_helper(struct kgdb_state *ks) 495 { 496 struct task_struct *thread; 497 void *local_debuggerinfo; 498 int i; 499 500 thread = kgdb_usethread; 501 if (!thread) { 502 thread = kgdb_info[ks->cpu].task; 503 local_debuggerinfo = kgdb_info[ks->cpu].debuggerinfo; 504 } else { 505 local_debuggerinfo = NULL; 506 for_each_online_cpu(i) { 507 /* 508 * Try to find the task on some other 509 * or possibly this node if we do not 510 * find the matching task then we try 511 * to approximate the results. 512 */ 513 if (thread == kgdb_info[i].task) 514 local_debuggerinfo = kgdb_info[i].debuggerinfo; 515 } 516 } 517 518 /* 519 * All threads that don't have debuggerinfo should be 520 * in schedule() sleeping, since all other CPUs 521 * are in kgdb_wait, and thus have debuggerinfo. 522 */ 523 if (local_debuggerinfo) { 524 pt_regs_to_gdb_regs(gdb_regs, local_debuggerinfo); 525 } else { 526 /* 527 * Pull stuff saved during switch_to; nothing 528 * else is accessible (or even particularly 529 * relevant). 530 * 531 * This should be enough for a stack trace. 532 */ 533 sleeping_thread_to_gdb_regs(gdb_regs, thread); 534 } 535 } 536 537 /* Handle the 'g' get registers request */ 538 static void gdb_cmd_getregs(struct kgdb_state *ks) 539 { 540 gdb_get_regs_helper(ks); 541 kgdb_mem2hex((char *)gdb_regs, remcom_out_buffer, NUMREGBYTES); 542 } 543 544 /* Handle the 'G' set registers request */ 545 static void gdb_cmd_setregs(struct kgdb_state *ks) 546 { 547 kgdb_hex2mem(&remcom_in_buffer[1], (char *)gdb_regs, NUMREGBYTES); 548 549 if (kgdb_usethread && kgdb_usethread != current) { 550 error_packet(remcom_out_buffer, -EINVAL); 551 } else { 552 gdb_regs_to_pt_regs(gdb_regs, ks->linux_regs); 553 strcpy(remcom_out_buffer, "OK"); 554 } 555 } 556 557 /* Handle the 'm' memory read bytes */ 558 static void gdb_cmd_memread(struct kgdb_state *ks) 559 { 560 char *ptr = &remcom_in_buffer[1]; 561 unsigned long length; 562 unsigned long addr; 563 char *err; 564 565 if (kgdb_hex2long(&ptr, &addr) > 0 && *ptr++ == ',' && 566 kgdb_hex2long(&ptr, &length) > 0) { 567 err = kgdb_mem2hex((char *)addr, remcom_out_buffer, length); 568 if (!err) 569 error_packet(remcom_out_buffer, -EINVAL); 570 } else { 571 error_packet(remcom_out_buffer, -EINVAL); 572 } 573 } 574 575 /* Handle the 'M' memory write bytes */ 576 static void gdb_cmd_memwrite(struct kgdb_state *ks) 577 { 578 int err = write_mem_msg(0); 579 580 if (err) 581 error_packet(remcom_out_buffer, err); 582 else 583 strcpy(remcom_out_buffer, "OK"); 584 } 585 586 #if DBG_MAX_REG_NUM > 0 587 static char *gdb_hex_reg_helper(int regnum, char *out) 588 { 589 int i; 590 int offset = 0; 591 592 for (i = 0; i < regnum; i++) 593 offset += dbg_reg_def[i].size; 594 return kgdb_mem2hex((char *)gdb_regs + offset, out, 595 dbg_reg_def[i].size); 596 } 597 598 /* Handle the 'p' individual register get */ 599 static void gdb_cmd_reg_get(struct kgdb_state *ks) 600 { 601 unsigned long regnum; 602 char *ptr = &remcom_in_buffer[1]; 603 604 kgdb_hex2long(&ptr, ®num); 605 if (regnum >= DBG_MAX_REG_NUM) { 606 error_packet(remcom_out_buffer, -EINVAL); 607 return; 608 } 609 gdb_get_regs_helper(ks); 610 gdb_hex_reg_helper(regnum, remcom_out_buffer); 611 } 612 613 /* Handle the 'P' individual register set */ 614 static void gdb_cmd_reg_set(struct kgdb_state *ks) 615 { 616 unsigned long regnum; 617 char *ptr = &remcom_in_buffer[1]; 618 int i = 0; 619 620 kgdb_hex2long(&ptr, ®num); 621 if (*ptr++ != '=' || 622 !(!kgdb_usethread || kgdb_usethread == current) || 623 !dbg_get_reg(regnum, gdb_regs, ks->linux_regs)) { 624 error_packet(remcom_out_buffer, -EINVAL); 625 return; 626 } 627 memset(gdb_regs, 0, sizeof(gdb_regs)); 628 while (i < sizeof(gdb_regs) * 2) 629 if (hex_to_bin(ptr[i]) >= 0) 630 i++; 631 else 632 break; 633 i = i / 2; 634 kgdb_hex2mem(ptr, (char *)gdb_regs, i); 635 dbg_set_reg(regnum, gdb_regs, ks->linux_regs); 636 strcpy(remcom_out_buffer, "OK"); 637 } 638 #endif /* DBG_MAX_REG_NUM > 0 */ 639 640 /* Handle the 'X' memory binary write bytes */ 641 static void gdb_cmd_binwrite(struct kgdb_state *ks) 642 { 643 int err = write_mem_msg(1); 644 645 if (err) 646 error_packet(remcom_out_buffer, err); 647 else 648 strcpy(remcom_out_buffer, "OK"); 649 } 650 651 /* Handle the 'D' or 'k', detach or kill packets */ 652 static void gdb_cmd_detachkill(struct kgdb_state *ks) 653 { 654 int error; 655 656 /* The detach case */ 657 if (remcom_in_buffer[0] == 'D') { 658 error = dbg_remove_all_break(); 659 if (error < 0) { 660 error_packet(remcom_out_buffer, error); 661 } else { 662 strcpy(remcom_out_buffer, "OK"); 663 kgdb_connected = 0; 664 } 665 put_packet(remcom_out_buffer); 666 } else { 667 /* 668 * Assume the kill case, with no exit code checking, 669 * trying to force detach the debugger: 670 */ 671 dbg_remove_all_break(); 672 kgdb_connected = 0; 673 } 674 } 675 676 /* Handle the 'R' reboot packets */ 677 static int gdb_cmd_reboot(struct kgdb_state *ks) 678 { 679 /* For now, only honor R0 */ 680 if (strcmp(remcom_in_buffer, "R0") == 0) { 681 printk(KERN_CRIT "Executing emergency reboot\n"); 682 strcpy(remcom_out_buffer, "OK"); 683 put_packet(remcom_out_buffer); 684 685 /* 686 * Execution should not return from 687 * machine_emergency_restart() 688 */ 689 machine_emergency_restart(); 690 kgdb_connected = 0; 691 692 return 1; 693 } 694 return 0; 695 } 696 697 /* Handle the 'q' query packets */ 698 static void gdb_cmd_query(struct kgdb_state *ks) 699 { 700 struct task_struct *g; 701 struct task_struct *p; 702 unsigned char thref[BUF_THREAD_ID_SIZE]; 703 char *ptr; 704 int i; 705 int cpu; 706 int finished = 0; 707 708 switch (remcom_in_buffer[1]) { 709 case 's': 710 case 'f': 711 if (memcmp(remcom_in_buffer + 2, "ThreadInfo", 10)) 712 break; 713 714 i = 0; 715 remcom_out_buffer[0] = 'm'; 716 ptr = remcom_out_buffer + 1; 717 if (remcom_in_buffer[1] == 'f') { 718 /* Each cpu is a shadow thread */ 719 for_each_online_cpu(cpu) { 720 ks->thr_query = 0; 721 int_to_threadref(thref, -cpu - 2); 722 ptr = pack_threadid(ptr, thref); 723 *(ptr++) = ','; 724 i++; 725 } 726 } 727 728 for_each_process_thread(g, p) { 729 if (i >= ks->thr_query && !finished) { 730 int_to_threadref(thref, p->pid); 731 ptr = pack_threadid(ptr, thref); 732 *(ptr++) = ','; 733 ks->thr_query++; 734 if (ks->thr_query % KGDB_MAX_THREAD_QUERY == 0) 735 finished = 1; 736 } 737 i++; 738 } 739 740 *(--ptr) = '\0'; 741 break; 742 743 case 'C': 744 /* Current thread id */ 745 strcpy(remcom_out_buffer, "QC"); 746 ks->threadid = shadow_pid(current->pid); 747 int_to_threadref(thref, ks->threadid); 748 pack_threadid(remcom_out_buffer + 2, thref); 749 break; 750 case 'T': 751 if (memcmp(remcom_in_buffer + 1, "ThreadExtraInfo,", 16)) 752 break; 753 754 ks->threadid = 0; 755 ptr = remcom_in_buffer + 17; 756 kgdb_hex2long(&ptr, &ks->threadid); 757 if (!getthread(ks->linux_regs, ks->threadid)) { 758 error_packet(remcom_out_buffer, -EINVAL); 759 break; 760 } 761 if ((int)ks->threadid > 0) { 762 kgdb_mem2hex(getthread(ks->linux_regs, 763 ks->threadid)->comm, 764 remcom_out_buffer, 16); 765 } else { 766 static char tmpstr[23 + BUF_THREAD_ID_SIZE]; 767 768 sprintf(tmpstr, "shadowCPU%d", 769 (int)(-ks->threadid - 2)); 770 kgdb_mem2hex(tmpstr, remcom_out_buffer, strlen(tmpstr)); 771 } 772 break; 773 #ifdef CONFIG_KGDB_KDB 774 case 'R': 775 if (strncmp(remcom_in_buffer, "qRcmd,", 6) == 0) { 776 int len = strlen(remcom_in_buffer + 6); 777 778 if ((len % 2) != 0) { 779 strcpy(remcom_out_buffer, "E01"); 780 break; 781 } 782 kgdb_hex2mem(remcom_in_buffer + 6, 783 remcom_out_buffer, len); 784 len = len / 2; 785 remcom_out_buffer[len++] = 0; 786 787 kdb_common_init_state(ks); 788 kdb_parse(remcom_out_buffer); 789 kdb_common_deinit_state(); 790 791 strcpy(remcom_out_buffer, "OK"); 792 } 793 break; 794 #endif 795 #ifdef CONFIG_HAVE_ARCH_KGDB_QXFER_PKT 796 case 'S': 797 if (!strncmp(remcom_in_buffer, "qSupported:", 11)) 798 strcpy(remcom_out_buffer, kgdb_arch_gdb_stub_feature); 799 break; 800 case 'X': 801 if (!strncmp(remcom_in_buffer, "qXfer:", 6)) 802 kgdb_arch_handle_qxfer_pkt(remcom_in_buffer, 803 remcom_out_buffer); 804 break; 805 #endif 806 default: 807 break; 808 } 809 } 810 811 /* Handle the 'H' task query packets */ 812 static void gdb_cmd_task(struct kgdb_state *ks) 813 { 814 struct task_struct *thread; 815 char *ptr; 816 817 switch (remcom_in_buffer[1]) { 818 case 'g': 819 ptr = &remcom_in_buffer[2]; 820 kgdb_hex2long(&ptr, &ks->threadid); 821 thread = getthread(ks->linux_regs, ks->threadid); 822 if (!thread && ks->threadid > 0) { 823 error_packet(remcom_out_buffer, -EINVAL); 824 break; 825 } 826 kgdb_usethread = thread; 827 ks->kgdb_usethreadid = ks->threadid; 828 strcpy(remcom_out_buffer, "OK"); 829 break; 830 case 'c': 831 ptr = &remcom_in_buffer[2]; 832 kgdb_hex2long(&ptr, &ks->threadid); 833 if (!ks->threadid) { 834 kgdb_contthread = NULL; 835 } else { 836 thread = getthread(ks->linux_regs, ks->threadid); 837 if (!thread && ks->threadid > 0) { 838 error_packet(remcom_out_buffer, -EINVAL); 839 break; 840 } 841 kgdb_contthread = thread; 842 } 843 strcpy(remcom_out_buffer, "OK"); 844 break; 845 } 846 } 847 848 /* Handle the 'T' thread query packets */ 849 static void gdb_cmd_thread(struct kgdb_state *ks) 850 { 851 char *ptr = &remcom_in_buffer[1]; 852 struct task_struct *thread; 853 854 kgdb_hex2long(&ptr, &ks->threadid); 855 thread = getthread(ks->linux_regs, ks->threadid); 856 if (thread) 857 strcpy(remcom_out_buffer, "OK"); 858 else 859 error_packet(remcom_out_buffer, -EINVAL); 860 } 861 862 /* Handle the 'z' or 'Z' breakpoint remove or set packets */ 863 static void gdb_cmd_break(struct kgdb_state *ks) 864 { 865 /* 866 * Since GDB-5.3, it's been drafted that '0' is a software 867 * breakpoint, '1' is a hardware breakpoint, so let's do that. 868 */ 869 char *bpt_type = &remcom_in_buffer[1]; 870 char *ptr = &remcom_in_buffer[2]; 871 unsigned long addr; 872 unsigned long length; 873 int error = 0; 874 875 if (arch_kgdb_ops.set_hw_breakpoint && *bpt_type >= '1') { 876 /* Unsupported */ 877 if (*bpt_type > '4') 878 return; 879 } else { 880 if (*bpt_type != '0' && *bpt_type != '1') 881 /* Unsupported. */ 882 return; 883 } 884 885 /* 886 * Test if this is a hardware breakpoint, and 887 * if we support it: 888 */ 889 if (*bpt_type == '1' && !(arch_kgdb_ops.flags & KGDB_HW_BREAKPOINT)) 890 /* Unsupported. */ 891 return; 892 893 if (*(ptr++) != ',') { 894 error_packet(remcom_out_buffer, -EINVAL); 895 return; 896 } 897 if (!kgdb_hex2long(&ptr, &addr)) { 898 error_packet(remcom_out_buffer, -EINVAL); 899 return; 900 } 901 if (*(ptr++) != ',' || 902 !kgdb_hex2long(&ptr, &length)) { 903 error_packet(remcom_out_buffer, -EINVAL); 904 return; 905 } 906 907 if (remcom_in_buffer[0] == 'Z' && *bpt_type == '0') 908 error = dbg_set_sw_break(addr); 909 else if (remcom_in_buffer[0] == 'z' && *bpt_type == '0') 910 error = dbg_remove_sw_break(addr); 911 else if (remcom_in_buffer[0] == 'Z') 912 error = arch_kgdb_ops.set_hw_breakpoint(addr, 913 (int)length, *bpt_type - '0'); 914 else if (remcom_in_buffer[0] == 'z') 915 error = arch_kgdb_ops.remove_hw_breakpoint(addr, 916 (int) length, *bpt_type - '0'); 917 918 if (error == 0) 919 strcpy(remcom_out_buffer, "OK"); 920 else 921 error_packet(remcom_out_buffer, error); 922 } 923 924 /* Handle the 'C' signal / exception passing packets */ 925 static int gdb_cmd_exception_pass(struct kgdb_state *ks) 926 { 927 /* C09 == pass exception 928 * C15 == detach kgdb, pass exception 929 */ 930 if (remcom_in_buffer[1] == '0' && remcom_in_buffer[2] == '9') { 931 932 ks->pass_exception = 1; 933 remcom_in_buffer[0] = 'c'; 934 935 } else if (remcom_in_buffer[1] == '1' && remcom_in_buffer[2] == '5') { 936 937 ks->pass_exception = 1; 938 remcom_in_buffer[0] = 'D'; 939 dbg_remove_all_break(); 940 kgdb_connected = 0; 941 return 1; 942 943 } else { 944 gdbstub_msg_write("KGDB only knows signal 9 (pass)" 945 " and 15 (pass and disconnect)\n" 946 "Executing a continue without signal passing\n", 0); 947 remcom_in_buffer[0] = 'c'; 948 } 949 950 /* Indicate fall through */ 951 return -1; 952 } 953 954 /* 955 * This function performs all gdbserial command procesing 956 */ 957 int gdb_serial_stub(struct kgdb_state *ks) 958 { 959 int error = 0; 960 int tmp; 961 962 /* Initialize comm buffer and globals. */ 963 memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer)); 964 kgdb_usethread = kgdb_info[ks->cpu].task; 965 ks->kgdb_usethreadid = shadow_pid(kgdb_info[ks->cpu].task->pid); 966 ks->pass_exception = 0; 967 968 if (kgdb_connected) { 969 unsigned char thref[BUF_THREAD_ID_SIZE]; 970 char *ptr; 971 972 /* Reply to host that an exception has occurred */ 973 ptr = remcom_out_buffer; 974 *ptr++ = 'T'; 975 ptr = hex_byte_pack(ptr, ks->signo); 976 ptr += strlen(strcpy(ptr, "thread:")); 977 int_to_threadref(thref, shadow_pid(current->pid)); 978 ptr = pack_threadid(ptr, thref); 979 *ptr++ = ';'; 980 put_packet(remcom_out_buffer); 981 } 982 983 while (1) { 984 error = 0; 985 986 /* Clear the out buffer. */ 987 memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer)); 988 989 get_packet(remcom_in_buffer); 990 991 switch (remcom_in_buffer[0]) { 992 case '?': /* gdbserial status */ 993 gdb_cmd_status(ks); 994 break; 995 case 'g': /* return the value of the CPU registers */ 996 gdb_cmd_getregs(ks); 997 break; 998 case 'G': /* set the value of the CPU registers - return OK */ 999 gdb_cmd_setregs(ks); 1000 break; 1001 case 'm': /* mAA..AA,LLLL Read LLLL bytes at address AA..AA */ 1002 gdb_cmd_memread(ks); 1003 break; 1004 case 'M': /* MAA..AA,LLLL: Write LLLL bytes at address AA..AA */ 1005 gdb_cmd_memwrite(ks); 1006 break; 1007 #if DBG_MAX_REG_NUM > 0 1008 case 'p': /* pXX Return gdb register XX (in hex) */ 1009 gdb_cmd_reg_get(ks); 1010 break; 1011 case 'P': /* PXX=aaaa Set gdb register XX to aaaa (in hex) */ 1012 gdb_cmd_reg_set(ks); 1013 break; 1014 #endif /* DBG_MAX_REG_NUM > 0 */ 1015 case 'X': /* XAA..AA,LLLL: Write LLLL bytes at address AA..AA */ 1016 gdb_cmd_binwrite(ks); 1017 break; 1018 /* kill or detach. KGDB should treat this like a 1019 * continue. 1020 */ 1021 case 'D': /* Debugger detach */ 1022 case 'k': /* Debugger detach via kill */ 1023 gdb_cmd_detachkill(ks); 1024 goto default_handle; 1025 case 'R': /* Reboot */ 1026 if (gdb_cmd_reboot(ks)) 1027 goto default_handle; 1028 break; 1029 case 'q': /* query command */ 1030 gdb_cmd_query(ks); 1031 break; 1032 case 'H': /* task related */ 1033 gdb_cmd_task(ks); 1034 break; 1035 case 'T': /* Query thread status */ 1036 gdb_cmd_thread(ks); 1037 break; 1038 case 'z': /* Break point remove */ 1039 case 'Z': /* Break point set */ 1040 gdb_cmd_break(ks); 1041 break; 1042 #ifdef CONFIG_KGDB_KDB 1043 case '3': /* Escape into back into kdb */ 1044 if (remcom_in_buffer[1] == '\0') { 1045 gdb_cmd_detachkill(ks); 1046 return DBG_PASS_EVENT; 1047 } 1048 #endif 1049 fallthrough; 1050 case 'C': /* Exception passing */ 1051 tmp = gdb_cmd_exception_pass(ks); 1052 if (tmp > 0) 1053 goto default_handle; 1054 if (tmp == 0) 1055 break; 1056 fallthrough; /* on tmp < 0 */ 1057 case 'c': /* Continue packet */ 1058 case 's': /* Single step packet */ 1059 if (kgdb_contthread && kgdb_contthread != current) { 1060 /* Can't switch threads in kgdb */ 1061 error_packet(remcom_out_buffer, -EINVAL); 1062 break; 1063 } 1064 fallthrough; /* to default processing */ 1065 default: 1066 default_handle: 1067 error = kgdb_arch_handle_exception(ks->ex_vector, 1068 ks->signo, 1069 ks->err_code, 1070 remcom_in_buffer, 1071 remcom_out_buffer, 1072 ks->linux_regs); 1073 /* 1074 * Leave cmd processing on error, detach, 1075 * kill, continue, or single step. 1076 */ 1077 if (error >= 0 || remcom_in_buffer[0] == 'D' || 1078 remcom_in_buffer[0] == 'k') { 1079 error = 0; 1080 goto kgdb_exit; 1081 } 1082 1083 } 1084 1085 /* reply to the request */ 1086 put_packet(remcom_out_buffer); 1087 } 1088 1089 kgdb_exit: 1090 if (ks->pass_exception) 1091 error = 1; 1092 return error; 1093 } 1094 1095 int gdbstub_state(struct kgdb_state *ks, char *cmd) 1096 { 1097 int error; 1098 1099 switch (cmd[0]) { 1100 case 'e': 1101 error = kgdb_arch_handle_exception(ks->ex_vector, 1102 ks->signo, 1103 ks->err_code, 1104 remcom_in_buffer, 1105 remcom_out_buffer, 1106 ks->linux_regs); 1107 return error; 1108 case 's': 1109 case 'c': 1110 strscpy(remcom_in_buffer, cmd, sizeof(remcom_in_buffer)); 1111 return 0; 1112 case '$': 1113 strscpy(remcom_in_buffer, cmd, sizeof(remcom_in_buffer)); 1114 gdbstub_use_prev_in_buf = strlen(remcom_in_buffer); 1115 gdbstub_prev_in_buf_pos = 0; 1116 return 0; 1117 } 1118 dbg_io_ops->write_char('+'); 1119 put_packet(remcom_out_buffer); 1120 return 0; 1121 } 1122 1123 /** 1124 * gdbstub_exit - Send an exit message to GDB 1125 * @status: The exit code to report. 1126 */ 1127 void gdbstub_exit(int status) 1128 { 1129 unsigned char checksum, ch, buffer[3]; 1130 int loop; 1131 1132 if (!kgdb_connected) 1133 return; 1134 kgdb_connected = 0; 1135 1136 if (!dbg_io_ops || dbg_kdb_mode) 1137 return; 1138 1139 buffer[0] = 'W'; 1140 buffer[1] = hex_asc_hi(status); 1141 buffer[2] = hex_asc_lo(status); 1142 1143 dbg_io_ops->write_char('$'); 1144 checksum = 0; 1145 1146 for (loop = 0; loop < 3; loop++) { 1147 ch = buffer[loop]; 1148 checksum += ch; 1149 dbg_io_ops->write_char(ch); 1150 } 1151 1152 dbg_io_ops->write_char('#'); 1153 dbg_io_ops->write_char(hex_asc_hi(checksum)); 1154 dbg_io_ops->write_char(hex_asc_lo(checksum)); 1155 1156 /* make sure the output is flushed, lest the bootloader clobber it */ 1157 if (dbg_io_ops->flush) 1158 dbg_io_ops->flush(); 1159 } 1160