linux/kernel/debug/gdbstub.c
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   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/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. */
  43static char                     remcom_in_buffer[BUFMAX];
  44static char                     remcom_out_buffer[BUFMAX];
  45static int                      gdbstub_use_prev_in_buf;
  46static int                      gdbstub_prev_in_buf_pos;
  47
  48/* Storage for the registers, in GDB format. */
  49static unsigned long            gdb_regs[(NUMREGBYTES +
  50                                        sizeof(unsigned long) - 1) /
  51                                        sizeof(unsigned long)];
  52
  53/*
  54 * GDB remote protocol parser:
  55 */
  56
  57#ifdef CONFIG_KGDB_KDB
  58static int gdbstub_read_wait(void)
  59{
  60        int ret = -1;
  61        int i;
  62
  63        if (unlikely(gdbstub_use_prev_in_buf)) {
  64                if (gdbstub_prev_in_buf_pos < gdbstub_use_prev_in_buf)
  65                        return remcom_in_buffer[gdbstub_prev_in_buf_pos++];
  66                else
  67                        gdbstub_use_prev_in_buf = 0;
  68        }
  69
  70        /* poll any additional I/O interfaces that are defined */
  71        while (ret < 0)
  72                for (i = 0; kdb_poll_funcs[i] != NULL; i++) {
  73                        ret = kdb_poll_funcs[i]();
  74                        if (ret > 0)
  75                                break;
  76                }
  77        return ret;
  78}
  79#else
  80static int gdbstub_read_wait(void)
  81{
  82        int ret = dbg_io_ops->read_char();
  83        while (ret == NO_POLL_CHAR)
  84                ret = dbg_io_ops->read_char();
  85        return ret;
  86}
  87#endif
  88/* scan for the sequence $<data>#<checksum> */
  89static void get_packet(char *buffer)
  90{
  91        unsigned char checksum;
  92        unsigned char xmitcsum;
  93        int count;
  94        char ch;
  95
  96        do {
  97                /*
  98                 * Spin and wait around for the start character, ignore all
  99                 * other characters:
 100                 */
 101                while ((ch = (gdbstub_read_wait())) != '$')
 102                        /* nothing */;
 103
 104                kgdb_connected = 1;
 105                checksum = 0;
 106                xmitcsum = -1;
 107
 108                count = 0;
 109
 110                /*
 111                 * now, read until a # or end of buffer is found:
 112                 */
 113                while (count < (BUFMAX - 1)) {
 114                        ch = gdbstub_read_wait();
 115                        if (ch == '#')
 116                                break;
 117                        checksum = checksum + ch;
 118                        buffer[count] = ch;
 119                        count = count + 1;
 120                }
 121
 122                if (ch == '#') {
 123                        xmitcsum = hex_to_bin(gdbstub_read_wait()) << 4;
 124                        xmitcsum += hex_to_bin(gdbstub_read_wait());
 125
 126                        if (checksum != xmitcsum)
 127                                /* failed checksum */
 128                                dbg_io_ops->write_char('-');
 129                        else
 130                                /* successful transfer */
 131                                dbg_io_ops->write_char('+');
 132                        if (dbg_io_ops->flush)
 133                                dbg_io_ops->flush();
 134                }
 135                buffer[count] = 0;
 136        } while (checksum != xmitcsum);
 137}
 138
 139/*
 140 * Send the packet in buffer.
 141 * Check for gdb connection if asked for.
 142 */
 143static void put_packet(char *buffer)
 144{
 145        unsigned char checksum;
 146        int count;
 147        char ch;
 148
 149        /*
 150         * $<packet info>#<checksum>.
 151         */
 152        while (1) {
 153                dbg_io_ops->write_char('$');
 154                checksum = 0;
 155                count = 0;
 156
 157                while ((ch = buffer[count])) {
 158                        dbg_io_ops->write_char(ch);
 159                        checksum += ch;
 160                        count++;
 161                }
 162
 163                dbg_io_ops->write_char('#');
 164                dbg_io_ops->write_char(hex_asc_hi(checksum));
 165                dbg_io_ops->write_char(hex_asc_lo(checksum));
 166                if (dbg_io_ops->flush)
 167                        dbg_io_ops->flush();
 168
 169                /* Now see what we get in reply. */
 170                ch = gdbstub_read_wait();
 171
 172                if (ch == 3)
 173                        ch = gdbstub_read_wait();
 174
 175                /* If we get an ACK, we are done. */
 176                if (ch == '+')
 177                        return;
 178
 179                /*
 180                 * If we get the start of another packet, this means
 181                 * that GDB is attempting to reconnect.  We will NAK
 182                 * the packet being sent, and stop trying to send this
 183                 * packet.
 184                 */
 185                if (ch == '$') {
 186                        dbg_io_ops->write_char('-');
 187                        if (dbg_io_ops->flush)
 188                                dbg_io_ops->flush();
 189                        return;
 190                }
 191        }
 192}
 193
 194static char gdbmsgbuf[BUFMAX + 1];
 195
 196void gdbstub_msg_write(const char *s, int len)
 197{
 198        char *bufptr;
 199        int wcount;
 200        int i;
 201
 202        if (len == 0)
 203                len = strlen(s);
 204
 205        /* 'O'utput */
 206        gdbmsgbuf[0] = 'O';
 207
 208        /* Fill and send buffers... */
 209        while (len > 0) {
 210                bufptr = gdbmsgbuf + 1;
 211
 212                /* Calculate how many this time */
 213                if ((len << 1) > (BUFMAX - 2))
 214                        wcount = (BUFMAX - 2) >> 1;
 215                else
 216                        wcount = len;
 217
 218                /* Pack in hex chars */
 219                for (i = 0; i < wcount; i++)
 220                        bufptr = hex_byte_pack(bufptr, s[i]);
 221                *bufptr = '\0';
 222
 223                /* Move up */
 224                s += wcount;
 225                len -= wcount;
 226
 227                /* Write packet */
 228                put_packet(gdbmsgbuf);
 229        }
 230}
 231
 232/*
 233 * Convert the memory pointed to by mem into hex, placing result in
 234 * buf.  Return a pointer to the last char put in buf (null). May
 235 * return an error.
 236 */
 237char *kgdb_mem2hex(char *mem, char *buf, int count)
 238{
 239        char *tmp;
 240        int err;
 241
 242        /*
 243         * We use the upper half of buf as an intermediate buffer for the
 244         * raw memory copy.  Hex conversion will work against this one.
 245         */
 246        tmp = buf + count;
 247
 248        err = probe_kernel_read(tmp, mem, count);
 249        if (err)
 250                return NULL;
 251        while (count > 0) {
 252                buf = hex_byte_pack(buf, *tmp);
 253                tmp++;
 254                count--;
 255        }
 256        *buf = 0;
 257
 258        return buf;
 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 */
 266int 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_to_bin(*tmp_hex--);
 281                *tmp_raw |= hex_to_bin(*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 */
 291int 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_to_bin(**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 */
 324static 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#if DBG_MAX_REG_NUM > 0
 340void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
 341{
 342        int i;
 343        int idx = 0;
 344        char *ptr = (char *)gdb_regs;
 345
 346        for (i = 0; i < DBG_MAX_REG_NUM; i++) {
 347                dbg_get_reg(i, ptr + idx, regs);
 348                idx += dbg_reg_def[i].size;
 349        }
 350}
 351
 352void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs)
 353{
 354        int i;
 355        int idx = 0;
 356        char *ptr = (char *)gdb_regs;
 357
 358        for (i = 0; i < DBG_MAX_REG_NUM; i++) {
 359                dbg_set_reg(i, ptr + idx, regs);
 360                idx += dbg_reg_def[i].size;
 361        }
 362}
 363#endif /* DBG_MAX_REG_NUM > 0 */
 364
 365/* Write memory due to an 'M' or 'X' packet. */
 366static int write_mem_msg(int binary)
 367{
 368        char *ptr = &remcom_in_buffer[1];
 369        unsigned long addr;
 370        unsigned long length;
 371        int err;
 372
 373        if (kgdb_hex2long(&ptr, &addr) > 0 && *(ptr++) == ',' &&
 374            kgdb_hex2long(&ptr, &length) > 0 && *(ptr++) == ':') {
 375                if (binary)
 376                        err = kgdb_ebin2mem(ptr, (char *)addr, length);
 377                else
 378                        err = kgdb_hex2mem(ptr, (char *)addr, length);
 379                if (err)
 380                        return err;
 381                if (CACHE_FLUSH_IS_SAFE)
 382                        flush_icache_range(addr, addr + length);
 383                return 0;
 384        }
 385
 386        return -EINVAL;
 387}
 388
 389static void error_packet(char *pkt, int error)
 390{
 391        error = -error;
 392        pkt[0] = 'E';
 393        pkt[1] = hex_asc[(error / 10)];
 394        pkt[2] = hex_asc[(error % 10)];
 395        pkt[3] = '\0';
 396}
 397
 398/*
 399 * Thread ID accessors. We represent a flat TID space to GDB, where
 400 * the per CPU idle threads (which under Linux all have PID 0) are
 401 * remapped to negative TIDs.
 402 */
 403
 404#define BUF_THREAD_ID_SIZE      8
 405
 406static char *pack_threadid(char *pkt, unsigned char *id)
 407{
 408        unsigned char *limit;
 409        int lzero = 1;
 410
 411        limit = id + (BUF_THREAD_ID_SIZE / 2);
 412        while (id < limit) {
 413                if (!lzero || *id != 0) {
 414                        pkt = hex_byte_pack(pkt, *id);
 415                        lzero = 0;
 416                }
 417                id++;
 418        }
 419
 420        if (lzero)
 421                pkt = hex_byte_pack(pkt, 0);
 422
 423        return pkt;
 424}
 425
 426static void int_to_threadref(unsigned char *id, int value)
 427{
 428        put_unaligned_be32(value, id);
 429}
 430
 431static struct task_struct *getthread(struct pt_regs *regs, int tid)
 432{
 433        /*
 434         * Non-positive TIDs are remapped to the cpu shadow information
 435         */
 436        if (tid == 0 || tid == -1)
 437                tid = -atomic_read(&kgdb_active) - 2;
 438        if (tid < -1 && tid > -NR_CPUS - 2) {
 439                if (kgdb_info[-tid - 2].task)
 440                        return kgdb_info[-tid - 2].task;
 441                else
 442                        return idle_task(-tid - 2);
 443        }
 444        if (tid <= 0) {
 445                printk(KERN_ERR "KGDB: Internal thread select error\n");
 446                dump_stack();
 447                return NULL;
 448        }
 449
 450        /*
 451         * find_task_by_pid_ns() does not take the tasklist lock anymore
 452         * but is nicely RCU locked - hence is a pretty resilient
 453         * thing to use:
 454         */
 455        return find_task_by_pid_ns(tid, &init_pid_ns);
 456}
 457
 458
 459/*
 460 * Remap normal tasks to their real PID,
 461 * CPU shadow threads are mapped to -CPU - 2
 462 */
 463static inline int shadow_pid(int realpid)
 464{
 465        if (realpid)
 466                return realpid;
 467
 468        return -raw_smp_processor_id() - 2;
 469}
 470
 471/*
 472 * All the functions that start with gdb_cmd are the various
 473 * operations to implement the handlers for the gdbserial protocol
 474 * where KGDB is communicating with an external debugger
 475 */
 476
 477/* Handle the '?' status packets */
 478static void gdb_cmd_status(struct kgdb_state *ks)
 479{
 480        /*
 481         * We know that this packet is only sent
 482         * during initial connect.  So to be safe,
 483         * we clear out our breakpoints now in case
 484         * GDB is reconnecting.
 485         */
 486        dbg_remove_all_break();
 487
 488        remcom_out_buffer[0] = 'S';
 489        hex_byte_pack(&remcom_out_buffer[1], ks->signo);
 490}
 491
 492static void gdb_get_regs_helper(struct kgdb_state *ks)
 493{
 494        struct task_struct *thread;
 495        void *local_debuggerinfo;
 496        int i;
 497
 498        thread = kgdb_usethread;
 499        if (!thread) {
 500                thread = kgdb_info[ks->cpu].task;
 501                local_debuggerinfo = kgdb_info[ks->cpu].debuggerinfo;
 502        } else {
 503                local_debuggerinfo = NULL;
 504                for_each_online_cpu(i) {
 505                        /*
 506                         * Try to find the task on some other
 507                         * or possibly this node if we do not
 508                         * find the matching task then we try
 509                         * to approximate the results.
 510                         */
 511                        if (thread == kgdb_info[i].task)
 512                                local_debuggerinfo = kgdb_info[i].debuggerinfo;
 513                }
 514        }
 515
 516        /*
 517         * All threads that don't have debuggerinfo should be
 518         * in schedule() sleeping, since all other CPUs
 519         * are in kgdb_wait, and thus have debuggerinfo.
 520         */
 521        if (local_debuggerinfo) {
 522                pt_regs_to_gdb_regs(gdb_regs, local_debuggerinfo);
 523        } else {
 524                /*
 525                 * Pull stuff saved during switch_to; nothing
 526                 * else is accessible (or even particularly
 527                 * relevant).
 528                 *
 529                 * This should be enough for a stack trace.
 530                 */
 531                sleeping_thread_to_gdb_regs(gdb_regs, thread);
 532        }
 533}
 534
 535/* Handle the 'g' get registers request */
 536static void gdb_cmd_getregs(struct kgdb_state *ks)
 537{
 538        gdb_get_regs_helper(ks);
 539        kgdb_mem2hex((char *)gdb_regs, remcom_out_buffer, NUMREGBYTES);
 540}
 541
 542/* Handle the 'G' set registers request */
 543static void gdb_cmd_setregs(struct kgdb_state *ks)
 544{
 545        kgdb_hex2mem(&remcom_in_buffer[1], (char *)gdb_regs, NUMREGBYTES);
 546
 547        if (kgdb_usethread && kgdb_usethread != current) {
 548                error_packet(remcom_out_buffer, -EINVAL);
 549        } else {
 550                gdb_regs_to_pt_regs(gdb_regs, ks->linux_regs);
 551                strcpy(remcom_out_buffer, "OK");
 552        }
 553}
 554
 555/* Handle the 'm' memory read bytes */
 556static void gdb_cmd_memread(struct kgdb_state *ks)
 557{
 558        char *ptr = &remcom_in_buffer[1];
 559        unsigned long length;
 560        unsigned long addr;
 561        char *err;
 562
 563        if (kgdb_hex2long(&ptr, &addr) > 0 && *ptr++ == ',' &&
 564                                        kgdb_hex2long(&ptr, &length) > 0) {
 565                err = kgdb_mem2hex((char *)addr, remcom_out_buffer, length);
 566                if (!err)
 567                        error_packet(remcom_out_buffer, -EINVAL);
 568        } else {
 569                error_packet(remcom_out_buffer, -EINVAL);
 570        }
 571}
 572
 573/* Handle the 'M' memory write bytes */
 574static void gdb_cmd_memwrite(struct kgdb_state *ks)
 575{
 576        int err = write_mem_msg(0);
 577
 578        if (err)
 579                error_packet(remcom_out_buffer, err);
 580        else
 581                strcpy(remcom_out_buffer, "OK");
 582}
 583
 584#if DBG_MAX_REG_NUM > 0
 585static char *gdb_hex_reg_helper(int regnum, char *out)
 586{
 587        int i;
 588        int offset = 0;
 589
 590        for (i = 0; i < regnum; i++)
 591                offset += dbg_reg_def[i].size;
 592        return kgdb_mem2hex((char *)gdb_regs + offset, out,
 593                            dbg_reg_def[i].size);
 594}
 595
 596/* Handle the 'p' individual regster get */
 597static void gdb_cmd_reg_get(struct kgdb_state *ks)
 598{
 599        unsigned long regnum;
 600        char *ptr = &remcom_in_buffer[1];
 601
 602        kgdb_hex2long(&ptr, &regnum);
 603        if (regnum >= DBG_MAX_REG_NUM) {
 604                error_packet(remcom_out_buffer, -EINVAL);
 605                return;
 606        }
 607        gdb_get_regs_helper(ks);
 608        gdb_hex_reg_helper(regnum, remcom_out_buffer);
 609}
 610
 611/* Handle the 'P' individual regster set */
 612static void gdb_cmd_reg_set(struct kgdb_state *ks)
 613{
 614        unsigned long regnum;
 615        char *ptr = &remcom_in_buffer[1];
 616        int i = 0;
 617
 618        kgdb_hex2long(&ptr, &regnum);
 619        if (*ptr++ != '=' ||
 620            !(!kgdb_usethread || kgdb_usethread == current) ||
 621            !dbg_get_reg(regnum, gdb_regs, ks->linux_regs)) {
 622                error_packet(remcom_out_buffer, -EINVAL);
 623                return;
 624        }
 625        memset(gdb_regs, 0, sizeof(gdb_regs));
 626        while (i < sizeof(gdb_regs) * 2)
 627                if (hex_to_bin(ptr[i]) >= 0)
 628                        i++;
 629                else
 630                        break;
 631        i = i / 2;
 632        kgdb_hex2mem(ptr, (char *)gdb_regs, i);
 633        dbg_set_reg(regnum, gdb_regs, ks->linux_regs);
 634        strcpy(remcom_out_buffer, "OK");
 635}
 636#endif /* DBG_MAX_REG_NUM > 0 */
 637
 638/* Handle the 'X' memory binary write bytes */
 639static void gdb_cmd_binwrite(struct kgdb_state *ks)
 640{
 641        int err = write_mem_msg(1);
 642
 643        if (err)
 644                error_packet(remcom_out_buffer, err);
 645        else
 646                strcpy(remcom_out_buffer, "OK");
 647}
 648
 649/* Handle the 'D' or 'k', detach or kill packets */
 650static void gdb_cmd_detachkill(struct kgdb_state *ks)
 651{
 652        int error;
 653
 654        /* The detach case */
 655        if (remcom_in_buffer[0] == 'D') {
 656                error = dbg_remove_all_break();
 657                if (error < 0) {
 658                        error_packet(remcom_out_buffer, error);
 659                } else {
 660                        strcpy(remcom_out_buffer, "OK");
 661                        kgdb_connected = 0;
 662                }
 663                put_packet(remcom_out_buffer);
 664        } else {
 665                /*
 666                 * Assume the kill case, with no exit code checking,
 667                 * trying to force detach the debugger:
 668                 */
 669                dbg_remove_all_break();
 670                kgdb_connected = 0;
 671        }
 672}
 673
 674/* Handle the 'R' reboot packets */
 675static int gdb_cmd_reboot(struct kgdb_state *ks)
 676{
 677        /* For now, only honor R0 */
 678        if (strcmp(remcom_in_buffer, "R0") == 0) {
 679                printk(KERN_CRIT "Executing emergency reboot\n");
 680                strcpy(remcom_out_buffer, "OK");
 681                put_packet(remcom_out_buffer);
 682
 683                /*
 684                 * Execution should not return from
 685                 * machine_emergency_restart()
 686                 */
 687                machine_emergency_restart();
 688                kgdb_connected = 0;
 689
 690                return 1;
 691        }
 692        return 0;
 693}
 694
 695/* Handle the 'q' query packets */
 696static void gdb_cmd_query(struct kgdb_state *ks)
 697{
 698        struct task_struct *g;
 699        struct task_struct *p;
 700        unsigned char thref[BUF_THREAD_ID_SIZE];
 701        char *ptr;
 702        int i;
 703        int cpu;
 704        int finished = 0;
 705
 706        switch (remcom_in_buffer[1]) {
 707        case 's':
 708        case 'f':
 709                if (memcmp(remcom_in_buffer + 2, "ThreadInfo", 10))
 710                        break;
 711
 712                i = 0;
 713                remcom_out_buffer[0] = 'm';
 714                ptr = remcom_out_buffer + 1;
 715                if (remcom_in_buffer[1] == 'f') {
 716                        /* Each cpu is a shadow thread */
 717                        for_each_online_cpu(cpu) {
 718                                ks->thr_query = 0;
 719                                int_to_threadref(thref, -cpu - 2);
 720                                ptr = pack_threadid(ptr, thref);
 721                                *(ptr++) = ',';
 722                                i++;
 723                        }
 724                }
 725
 726                do_each_thread(g, p) {
 727                        if (i >= ks->thr_query && !finished) {
 728                                int_to_threadref(thref, p->pid);
 729                                ptr = pack_threadid(ptr, thref);
 730                                *(ptr++) = ',';
 731                                ks->thr_query++;
 732                                if (ks->thr_query % KGDB_MAX_THREAD_QUERY == 0)
 733                                        finished = 1;
 734                        }
 735                        i++;
 736                } while_each_thread(g, p);
 737
 738                *(--ptr) = '\0';
 739                break;
 740
 741        case 'C':
 742                /* Current thread id */
 743                strcpy(remcom_out_buffer, "QC");
 744                ks->threadid = shadow_pid(current->pid);
 745                int_to_threadref(thref, ks->threadid);
 746                pack_threadid(remcom_out_buffer + 2, thref);
 747                break;
 748        case 'T':
 749                if (memcmp(remcom_in_buffer + 1, "ThreadExtraInfo,", 16))
 750                        break;
 751
 752                ks->threadid = 0;
 753                ptr = remcom_in_buffer + 17;
 754                kgdb_hex2long(&ptr, &ks->threadid);
 755                if (!getthread(ks->linux_regs, ks->threadid)) {
 756                        error_packet(remcom_out_buffer, -EINVAL);
 757                        break;
 758                }
 759                if ((int)ks->threadid > 0) {
 760                        kgdb_mem2hex(getthread(ks->linux_regs,
 761                                        ks->threadid)->comm,
 762                                        remcom_out_buffer, 16);
 763                } else {
 764                        static char tmpstr[23 + BUF_THREAD_ID_SIZE];
 765
 766                        sprintf(tmpstr, "shadowCPU%d",
 767                                        (int)(-ks->threadid - 2));
 768                        kgdb_mem2hex(tmpstr, remcom_out_buffer, strlen(tmpstr));
 769                }
 770                break;
 771#ifdef CONFIG_KGDB_KDB
 772        case 'R':
 773                if (strncmp(remcom_in_buffer, "qRcmd,", 6) == 0) {
 774                        int len = strlen(remcom_in_buffer + 6);
 775
 776                        if ((len % 2) != 0) {
 777                                strcpy(remcom_out_buffer, "E01");
 778                                break;
 779                        }
 780                        kgdb_hex2mem(remcom_in_buffer + 6,
 781                                     remcom_out_buffer, len);
 782                        len = len / 2;
 783                        remcom_out_buffer[len++] = 0;
 784
 785                        kdb_parse(remcom_out_buffer);
 786                        strcpy(remcom_out_buffer, "OK");
 787                }
 788                break;
 789#endif
 790        }
 791}
 792
 793/* Handle the 'H' task query packets */
 794static void gdb_cmd_task(struct kgdb_state *ks)
 795{
 796        struct task_struct *thread;
 797        char *ptr;
 798
 799        switch (remcom_in_buffer[1]) {
 800        case 'g':
 801                ptr = &remcom_in_buffer[2];
 802                kgdb_hex2long(&ptr, &ks->threadid);
 803                thread = getthread(ks->linux_regs, ks->threadid);
 804                if (!thread && ks->threadid > 0) {
 805                        error_packet(remcom_out_buffer, -EINVAL);
 806                        break;
 807                }
 808                kgdb_usethread = thread;
 809                ks->kgdb_usethreadid = ks->threadid;
 810                strcpy(remcom_out_buffer, "OK");
 811                break;
 812        case 'c':
 813                ptr = &remcom_in_buffer[2];
 814                kgdb_hex2long(&ptr, &ks->threadid);
 815                if (!ks->threadid) {
 816                        kgdb_contthread = NULL;
 817                } else {
 818                        thread = getthread(ks->linux_regs, ks->threadid);
 819                        if (!thread && ks->threadid > 0) {
 820                                error_packet(remcom_out_buffer, -EINVAL);
 821                                break;
 822                        }
 823                        kgdb_contthread = thread;
 824                }
 825                strcpy(remcom_out_buffer, "OK");
 826                break;
 827        }
 828}
 829
 830/* Handle the 'T' thread query packets */
 831static void gdb_cmd_thread(struct kgdb_state *ks)
 832{
 833        char *ptr = &remcom_in_buffer[1];
 834        struct task_struct *thread;
 835
 836        kgdb_hex2long(&ptr, &ks->threadid);
 837        thread = getthread(ks->linux_regs, ks->threadid);
 838        if (thread)
 839                strcpy(remcom_out_buffer, "OK");
 840        else
 841                error_packet(remcom_out_buffer, -EINVAL);
 842}
 843
 844/* Handle the 'z' or 'Z' breakpoint remove or set packets */
 845static void gdb_cmd_break(struct kgdb_state *ks)
 846{
 847        /*
 848         * Since GDB-5.3, it's been drafted that '0' is a software
 849         * breakpoint, '1' is a hardware breakpoint, so let's do that.
 850         */
 851        char *bpt_type = &remcom_in_buffer[1];
 852        char *ptr = &remcom_in_buffer[2];
 853        unsigned long addr;
 854        unsigned long length;
 855        int error = 0;
 856
 857        if (arch_kgdb_ops.set_hw_breakpoint && *bpt_type >= '1') {
 858                /* Unsupported */
 859                if (*bpt_type > '4')
 860                        return;
 861        } else {
 862                if (*bpt_type != '0' && *bpt_type != '1')
 863                        /* Unsupported. */
 864                        return;
 865        }
 866
 867        /*
 868         * Test if this is a hardware breakpoint, and
 869         * if we support it:
 870         */
 871        if (*bpt_type == '1' && !(arch_kgdb_ops.flags & KGDB_HW_BREAKPOINT))
 872                /* Unsupported. */
 873                return;
 874
 875        if (*(ptr++) != ',') {
 876                error_packet(remcom_out_buffer, -EINVAL);
 877                return;
 878        }
 879        if (!kgdb_hex2long(&ptr, &addr)) {
 880                error_packet(remcom_out_buffer, -EINVAL);
 881                return;
 882        }
 883        if (*(ptr++) != ',' ||
 884                !kgdb_hex2long(&ptr, &length)) {
 885                error_packet(remcom_out_buffer, -EINVAL);
 886                return;
 887        }
 888
 889        if (remcom_in_buffer[0] == 'Z' && *bpt_type == '0')
 890                error = dbg_set_sw_break(addr);
 891        else if (remcom_in_buffer[0] == 'z' && *bpt_type == '0')
 892                error = dbg_remove_sw_break(addr);
 893        else if (remcom_in_buffer[0] == 'Z')
 894                error = arch_kgdb_ops.set_hw_breakpoint(addr,
 895                        (int)length, *bpt_type - '0');
 896        else if (remcom_in_buffer[0] == 'z')
 897                error = arch_kgdb_ops.remove_hw_breakpoint(addr,
 898                        (int) length, *bpt_type - '0');
 899
 900        if (error == 0)
 901                strcpy(remcom_out_buffer, "OK");
 902        else
 903                error_packet(remcom_out_buffer, error);
 904}
 905
 906/* Handle the 'C' signal / exception passing packets */
 907static int gdb_cmd_exception_pass(struct kgdb_state *ks)
 908{
 909        /* C09 == pass exception
 910         * C15 == detach kgdb, pass exception
 911         */
 912        if (remcom_in_buffer[1] == '0' && remcom_in_buffer[2] == '9') {
 913
 914                ks->pass_exception = 1;
 915                remcom_in_buffer[0] = 'c';
 916
 917        } else if (remcom_in_buffer[1] == '1' && remcom_in_buffer[2] == '5') {
 918
 919                ks->pass_exception = 1;
 920                remcom_in_buffer[0] = 'D';
 921                dbg_remove_all_break();
 922                kgdb_connected = 0;
 923                return 1;
 924
 925        } else {
 926                gdbstub_msg_write("KGDB only knows signal 9 (pass)"
 927                        " and 15 (pass and disconnect)\n"
 928                        "Executing a continue without signal passing\n", 0);
 929                remcom_in_buffer[0] = 'c';
 930        }
 931
 932        /* Indicate fall through */
 933        return -1;
 934}
 935
 936/*
 937 * This function performs all gdbserial command procesing
 938 */
 939int gdb_serial_stub(struct kgdb_state *ks)
 940{
 941        int error = 0;
 942        int tmp;
 943
 944        /* Initialize comm buffer and globals. */
 945        memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer));
 946        kgdb_usethread = kgdb_info[ks->cpu].task;
 947        ks->kgdb_usethreadid = shadow_pid(kgdb_info[ks->cpu].task->pid);
 948        ks->pass_exception = 0;
 949
 950        if (kgdb_connected) {
 951                unsigned char thref[BUF_THREAD_ID_SIZE];
 952                char *ptr;
 953
 954                /* Reply to host that an exception has occurred */
 955                ptr = remcom_out_buffer;
 956                *ptr++ = 'T';
 957                ptr = hex_byte_pack(ptr, ks->signo);
 958                ptr += strlen(strcpy(ptr, "thread:"));
 959                int_to_threadref(thref, shadow_pid(current->pid));
 960                ptr = pack_threadid(ptr, thref);
 961                *ptr++ = ';';
 962                put_packet(remcom_out_buffer);
 963        }
 964
 965        while (1) {
 966                error = 0;
 967
 968                /* Clear the out buffer. */
 969                memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer));
 970
 971                get_packet(remcom_in_buffer);
 972
 973                switch (remcom_in_buffer[0]) {
 974                case '?': /* gdbserial status */
 975                        gdb_cmd_status(ks);
 976                        break;
 977                case 'g': /* return the value of the CPU registers */
 978                        gdb_cmd_getregs(ks);
 979                        break;
 980                case 'G': /* set the value of the CPU registers - return OK */
 981                        gdb_cmd_setregs(ks);
 982                        break;
 983                case 'm': /* mAA..AA,LLLL  Read LLLL bytes at address AA..AA */
 984                        gdb_cmd_memread(ks);
 985                        break;
 986                case 'M': /* MAA..AA,LLLL: Write LLLL bytes at address AA..AA */
 987                        gdb_cmd_memwrite(ks);
 988                        break;
 989#if DBG_MAX_REG_NUM > 0
 990                case 'p': /* pXX Return gdb register XX (in hex) */
 991                        gdb_cmd_reg_get(ks);
 992                        break;
 993                case 'P': /* PXX=aaaa Set gdb register XX to aaaa (in hex) */
 994                        gdb_cmd_reg_set(ks);
 995                        break;
 996#endif /* DBG_MAX_REG_NUM > 0 */
 997                case 'X': /* XAA..AA,LLLL: Write LLLL bytes at address AA..AA */
 998                        gdb_cmd_binwrite(ks);
 999                        break;
1000                        /* kill or detach. KGDB should treat this like a
1001                         * continue.
1002                         */
1003                case 'D': /* Debugger detach */
1004                case 'k': /* Debugger detach via kill */
1005                        gdb_cmd_detachkill(ks);
1006                        goto default_handle;
1007                case 'R': /* Reboot */
1008                        if (gdb_cmd_reboot(ks))
1009                                goto default_handle;
1010                        break;
1011                case 'q': /* query command */
1012                        gdb_cmd_query(ks);
1013                        break;
1014                case 'H': /* task related */
1015                        gdb_cmd_task(ks);
1016                        break;
1017                case 'T': /* Query thread status */
1018                        gdb_cmd_thread(ks);
1019                        break;
1020                case 'z': /* Break point remove */
1021                case 'Z': /* Break point set */
1022                        gdb_cmd_break(ks);
1023                        break;
1024#ifdef CONFIG_KGDB_KDB
1025                case '3': /* Escape into back into kdb */
1026                        if (remcom_in_buffer[1] == '\0') {
1027                                gdb_cmd_detachkill(ks);
1028                                return DBG_PASS_EVENT;
1029                        }
1030#endif
1031                case 'C': /* Exception passing */
1032                        tmp = gdb_cmd_exception_pass(ks);
1033                        if (tmp > 0)
1034                                goto default_handle;
1035                        if (tmp == 0)
1036                                break;
1037                        /* Fall through on tmp < 0 */
1038                case 'c': /* Continue packet */
1039                case 's': /* Single step packet */
1040                        if (kgdb_contthread && kgdb_contthread != current) {
1041                                /* Can't switch threads in kgdb */
1042                                error_packet(remcom_out_buffer, -EINVAL);
1043                                break;
1044                        }
1045                        dbg_activate_sw_breakpoints();
1046                        /* Fall through to default processing */
1047                default:
1048default_handle:
1049                        error = kgdb_arch_handle_exception(ks->ex_vector,
1050                                                ks->signo,
1051                                                ks->err_code,
1052                                                remcom_in_buffer,
1053                                                remcom_out_buffer,
1054                                                ks->linux_regs);
1055                        /*
1056                         * Leave cmd processing on error, detach,
1057                         * kill, continue, or single step.
1058                         */
1059                        if (error >= 0 || remcom_in_buffer[0] == 'D' ||
1060                            remcom_in_buffer[0] == 'k') {
1061                                error = 0;
1062                                goto kgdb_exit;
1063                        }
1064
1065                }
1066
1067                /* reply to the request */
1068                put_packet(remcom_out_buffer);
1069        }
1070
1071kgdb_exit:
1072        if (ks->pass_exception)
1073                error = 1;
1074        return error;
1075}
1076
1077int gdbstub_state(struct kgdb_state *ks, char *cmd)
1078{
1079        int error;
1080
1081        switch (cmd[0]) {
1082        case 'e':
1083                error = kgdb_arch_handle_exception(ks->ex_vector,
1084                                                   ks->signo,
1085                                                   ks->err_code,
1086                                                   remcom_in_buffer,
1087                                                   remcom_out_buffer,
1088                                                   ks->linux_regs);
1089                return error;
1090        case 's':
1091        case 'c':
1092                strcpy(remcom_in_buffer, cmd);
1093                return 0;
1094        case '$':
1095                strcpy(remcom_in_buffer, cmd);
1096                gdbstub_use_prev_in_buf = strlen(remcom_in_buffer);
1097                gdbstub_prev_in_buf_pos = 0;
1098                return 0;
1099        }
1100        dbg_io_ops->write_char('+');
1101        put_packet(remcom_out_buffer);
1102        return 0;
1103}
1104
1105/**
1106 * gdbstub_exit - Send an exit message to GDB
1107 * @status: The exit code to report.
1108 */
1109void gdbstub_exit(int status)
1110{
1111        unsigned char checksum, ch, buffer[3];
1112        int loop;
1113
1114        if (!kgdb_connected)
1115                return;
1116        kgdb_connected = 0;
1117
1118        if (!dbg_io_ops || dbg_kdb_mode)
1119                return;
1120
1121        buffer[0] = 'W';
1122        buffer[1] = hex_asc_hi(status);
1123        buffer[2] = hex_asc_lo(status);
1124
1125        dbg_io_ops->write_char('$');
1126        checksum = 0;
1127
1128        for (loop = 0; loop < 3; loop++) {
1129                ch = buffer[loop];
1130                checksum += ch;
1131                dbg_io_ops->write_char(ch);
1132        }
1133
1134        dbg_io_ops->write_char('#');
1135        dbg_io_ops->write_char(hex_asc_hi(checksum));
1136        dbg_io_ops->write_char(hex_asc_lo(checksum));
1137
1138        /* make sure the output is flushed, lest the bootloader clobber it */
1139        if (dbg_io_ops->flush)
1140                dbg_io_ops->flush();
1141}
1142
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