SAFE public projects git trees. - safe/jmp/linux-2.6/blob - kernel/debug/gdbstub.c

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