kernel/debug/kdb/kdb_io.c

   1 /*
   2  * Kernel Debugger Architecture Independent Console I/O handler
   3  *
   4  * This file is subject to the terms and conditions of the GNU General Public
   5  * License.  See the file "COPYING" in the main directory of this archive
   6  * for more details.
   7  *
   8  * Copyright (c) 1999-2006 Silicon Graphics, Inc.  All Rights Reserved.
   9  * Copyright (c) 2009 Wind River Systems, Inc.  All Rights Reserved.
  10  */
  11
  12 #include <linux/module.h>
  13 #include <linux/types.h>
  14 #include <linux/ctype.h>
  15 #include <linux/kernel.h>
  16 #include <linux/init.h>
  17 #include <linux/kdev_t.h>
  18 #include <linux/console.h>
  19 #include <linux/string.h>
  20 #include <linux/sched.h>
  21 #include <linux/smp.h>
  22 #include <linux/nmi.h>
  23 #include <linux/delay.h>
  24 #include <linux/kgdb.h>
  25 #include <linux/kdb.h>
  26 #include <linux/kallsyms.h>
  27 #include "kdb_private.h"
  28
  29 #define CMD_BUFLEN 256
  30 char kdb_prompt_str[CMD_BUFLEN];
  31
  32 int kdb_trap_printk;
  33
  34 static void kgdb_transition_check(char *buffer)
  35 {
  36         int slen = strlen(buffer);
  37         if (strncmp(buffer, "$?#3f", slen) != 0 &&
  38             strncmp(buffer, "$qSupported#37", slen) != 0 &&
  39             strncmp(buffer, "+$qSupported#37", slen) != 0) {
  40                 KDB_STATE_SET(KGDB_TRANS);
  41                 kdb_printf("%s", buffer);
  42         }
  43 }
  44
  45 static int kdb_read_get_key(char *buffer, size_t bufsize)
  46 {
  47 #define ESCAPE_UDELAY 1000
  48 #define ESCAPE_DELAY (2*1000000/ESCAPE_UDELAY) /* 2 seconds worth of udelays */
  49         char escape_data[5];    /* longest vt100 escape sequence is 4 bytes */
  50         char *ped = escape_data;
  51         int escape_delay = 0;
  52         get_char_func *f, *f_escape = NULL;
  53         int key;
  54
  55         for (f = &kdb_poll_funcs[0]; ; ++f) {
  56                 if (*f == NULL) {
  57                         /* Reset NMI watchdog once per poll loop */
  58                         touch_nmi_watchdog();
  59                         f = &kdb_poll_funcs[0];
  60                 }
  61                 if (escape_delay == 2) {
  62                         *ped = '\0';
  63                         ped = escape_data;
  64                         --escape_delay;
  65                 }
  66                 if (escape_delay == 1) {
  67                         key = *ped++;
  68                         if (!*ped)
  69                                 --escape_delay;
  70                         break;
  71                 }
  72                 key = (*f)();
  73                 if (key == -1) {
  74                         if (escape_delay) {
  75                                 udelay(ESCAPE_UDELAY);
  76                                 --escape_delay;
  77                         }
  78                         continue;
  79                 }
  80                 if (bufsize <= 2) {
  81                         if (key == '\r')
  82                                 key = '\n';
  83                         *buffer++ = key;
  84                         *buffer = '\0';
  85                         return -1;
  86                 }
  87                 if (escape_delay == 0 && key == '\e') {
  88                         escape_delay = ESCAPE_DELAY;
  89                         ped = escape_data;
  90                         f_escape = f;
  91                 }
  92                 if (escape_delay) {
  93                         *ped++ = key;
  94                         if (f_escape != f) {
  95                                 escape_delay = 2;
  96                                 continue;
  97                         }
  98                         if (ped - escape_data == 1) {
  99                                 /* \e */
 100                                 continue;
 101                         } else if (ped - escape_data == 2) {
 102                                 /* \e<something> */
 103                                 if (key != '[')
 104                                         escape_delay = 2;
 105                                 continue;
 106                         } else if (ped - escape_data == 3) {
 107                                 /* \e[<something> */
 108                                 int mapkey = 0;
 109                                 switch (key) {
 110                                 case 'A': /* \e[A, up arrow */
 111                                         mapkey = 16;
 112                                         break;
 113                                 case 'B': /* \e[B, down arrow */
 114                                         mapkey = 14;
 115                                         break;
 116                                 case 'C': /* \e[C, right arrow */
 117                                         mapkey = 6;
 118                                         break;
 119                                 case 'D': /* \e[D, left arrow */
 120                                         mapkey = 2;
 121                                         break;
 122                                 case '1': /* dropthrough */
 123                                 case '3': /* dropthrough */
 124                                 /* \e[<1,3,4>], may be home, del, end */
 125                                 case '4':
 126                                         mapkey = -1;
 127                                         break;
 128                                 }
 129                                 if (mapkey != -1) {
 130                                         if (mapkey > 0) {
 131                                                 escape_data[0] = mapkey;
 132                                                 escape_data[1] = '\0';
 133                                         }
 134                                         escape_delay = 2;
 135                                 }
 136                                 continue;
 137                         } else if (ped - escape_data == 4) {
 138                                 /* \e[<1,3,4><something> */
 139                                 int mapkey = 0;
 140                                 if (key == '~') {
 141                                         switch (escape_data[2]) {
 142                                         case '1': /* \e[1~, home */
 143                                                 mapkey = 1;
 144                                                 break;
 145                                         case '3': /* \e[3~, del */
 146                                                 mapkey = 4;
 147                                                 break;
 148                                         case '4': /* \e[4~, end */
 149                                                 mapkey = 5;
 150                                                 break;
 151                                         }
 152                                 }
 153                                 if (mapkey > 0) {
 154                                         escape_data[0] = mapkey;
 155                                         escape_data[1] = '\0';
 156                                 }
 157                                 escape_delay = 2;
 158                                 continue;
 159                         }
 160                 }
 161                 break;  /* A key to process */
 162         }
 163         return key;
 164 }
 165
 166 /*
 167  * kdb_read
 168  *
 169  *      This function reads a string of characters, terminated by
 170  *      a newline, or by reaching the end of the supplied buffer,
 171  *      from the current kernel debugger console device.
 172  * Parameters:
 173  *      buffer  - Address of character buffer to receive input characters.
 174  *      bufsize - size, in bytes, of the character buffer
 175  * Returns:
 176  *      Returns a pointer to the buffer containing the received
 177  *      character string.  This string will be terminated by a
 178  *      newline character.
 179  * Locking:
 180  *      No locks are required to be held upon entry to this
 181  *      function.  It is not reentrant - it relies on the fact
 182  *      that while kdb is running on only one "master debug" cpu.
 183  * Remarks:
 184  *
 185  * The buffer size must be >= 2.  A buffer size of 2 means that the caller only
 186  * wants a single key.
 187  *
 188  * An escape key could be the start of a vt100 control sequence such as \e[D
 189  * (left arrow) or it could be a character in its own right.  The standard
 190  * method for detecting the difference is to wait for 2 seconds to see if there
 191  * are any other characters.  kdb is complicated by the lack of a timer service
 192  * (interrupts are off), by multiple input sources and by the need to sometimes
 193  * return after just one key.  Escape sequence processing has to be done as
 194  * states in the polling loop.
 195  */
 196
 197 static char *kdb_read(char *buffer, size_t bufsize)
 198 {
 199         char *cp = buffer;
 200         char *bufend = buffer+bufsize-2;        /* Reserve space for newline
 201                                                  * and null byte */
 202         char *lastchar;
 203         char *p_tmp;
 204         char tmp;
 205         static char tmpbuffer[CMD_BUFLEN];
 206         int len = strlen(buffer);
 207         int len_tmp;
 208         int tab = 0;
 209         int count;
 210         int i;
 211         int diag, dtab_count;
 212         int key;
 213
 214
 215         diag = kdbgetintenv("DTABCOUNT", &dtab_count);
 216         if (diag)
 217                 dtab_count = 30;
 218
 219         if (len > 0) {
 220                 cp += len;
 221                 if (*(buffer+len-1) == '\n')
 222                         cp--;
 223         }
 224
 225         lastchar = cp;
 226         *cp = '\0';
 227         kdb_printf("%s", buffer);
 228 poll_again:
 229         key = kdb_read_get_key(buffer, bufsize);
 230         if (key == -1)
 231                 return buffer;
 232         if (key != 9)
 233                 tab = 0;
 234         switch (key) {
 235         case 8: /* backspace */
 236                 if (cp > buffer) {
 237                         if (cp < lastchar) {
 238                                 memcpy(tmpbuffer, cp, lastchar - cp);
 239                                 memcpy(cp-1, tmpbuffer, lastchar - cp);
 240                         }
 241                         *(--lastchar) = '\0';
 242                         --cp;
 243                         kdb_printf("\b%s \r", cp);
 244                         tmp = *cp;
 245                         *cp = '\0';
 246                         kdb_printf(kdb_prompt_str);
 247                         kdb_printf("%s", buffer);
 248                         *cp = tmp;
 249                 }
 250                 break;
 251         case 13: /* enter */
 252                 *lastchar++ = '\n';
 253                 *lastchar++ = '\0';
 254                 kdb_printf("\n");
 255                 return buffer;
 256         case 4: /* Del */
 257                 if (cp < lastchar) {
 258                         memcpy(tmpbuffer, cp+1, lastchar - cp - 1);
 259                         memcpy(cp, tmpbuffer, lastchar - cp - 1);
 260                         *(--lastchar) = '\0';
 261                         kdb_printf("%s \r", cp);
 262                         tmp = *cp;
 263                         *cp = '\0';
 264                         kdb_printf(kdb_prompt_str);
 265                         kdb_printf("%s", buffer);
 266                         *cp = tmp;
 267                 }
 268                 break;
 269         case 1: /* Home */
 270                 if (cp > buffer) {
 271                         kdb_printf("\r");
 272                         kdb_printf(kdb_prompt_str);
 273                         cp = buffer;
 274                 }
 275                 break;
 276         case 5: /* End */
 277                 if (cp < lastchar) {
 278                         kdb_printf("%s", cp);
 279                         cp = lastchar;
 280                 }
 281                 break;
 282         case 2: /* Left */
 283                 if (cp > buffer) {
 284                         kdb_printf("\b");
 285                         --cp;
 286                 }
 287                 break;
 288         case 14: /* Down */
 289                 memset(tmpbuffer, ' ',
 290                        strlen(kdb_prompt_str) + (lastchar-buffer));
 291                 *(tmpbuffer+strlen(kdb_prompt_str) +
 292                   (lastchar-buffer)) = '\0';
 293                 kdb_printf("\r%s\r", tmpbuffer);
 294                 *lastchar = (char)key;
 295                 *(lastchar+1) = '\0';
 296                 return lastchar;
 297         case 6: /* Right */
 298                 if (cp < lastchar) {
 299                         kdb_printf("%c", *cp);
 300                         ++cp;
 301                 }
 302                 break;
 303         case 16: /* Up */
 304                 memset(tmpbuffer, ' ',
 305                        strlen(kdb_prompt_str) + (lastchar-buffer));
 306                 *(tmpbuffer+strlen(kdb_prompt_str) +
 307                   (lastchar-buffer)) = '\0';
 308                 kdb_printf("\r%s\r", tmpbuffer);
 309                 *lastchar = (char)key;
 310                 *(lastchar+1) = '\0';
 311                 return lastchar;
 312         case 9: /* Tab */
 313                 if (tab < 2)
 314                         ++tab;
 315                 p_tmp = buffer;
 316                 while (*p_tmp == ' ')
 317                         p_tmp++;
 318                 if (p_tmp > cp)
 319                         break;
 320                 memcpy(tmpbuffer, p_tmp, cp-p_tmp);
 321                 *(tmpbuffer + (cp-p_tmp)) = '\0';
 322                 p_tmp = strrchr(tmpbuffer, ' ');
 323                 if (p_tmp)
 324                         ++p_tmp;
 325                 else
 326                         p_tmp = tmpbuffer;
 327                 len = strlen(p_tmp);
 328                 count = kallsyms_symbol_complete(p_tmp,
 329                                                  sizeof(tmpbuffer) -
 330                                                  (p_tmp - tmpbuffer));
 331                 if (tab == 2 && count > 0) {
 332                         kdb_printf("\n%d symbols are found.", count);
 333                         if (count > dtab_count) {
 334                                 count = dtab_count;
 335                                 kdb_printf(" But only first %d symbols will"
 336                                            " be printed.\nYou can change the"
 337                                            " environment variable DTABCOUNT.",
 338                                            count);
 339                         }
 340                         kdb_printf("\n");
 341                         for (i = 0; i < count; i++) {
 342                                 if (kallsyms_symbol_next(p_tmp, i) < 0)
 343                                         break;
 344                                 kdb_printf("%s ", p_tmp);
 345                                 *(p_tmp + len) = '\0';
 346                         }
 347                         if (i >= dtab_count)
 348                                 kdb_printf("...");
 349                         kdb_printf("\n");
 350                         kdb_printf(kdb_prompt_str);
 351                         kdb_printf("%s", buffer);
 352                 } else if (tab != 2 && count > 0) {
 353                         len_tmp = strlen(p_tmp);
 354                         strncpy(p_tmp+len_tmp, cp, lastchar-cp+1);
 355                         len_tmp = strlen(p_tmp);
 356                         strncpy(cp, p_tmp+len, len_tmp-len + 1);
 357                         len = len_tmp - len;
 358                         kdb_printf("%s", cp);
 359                         cp += len;
 360                         lastchar += len;
 361                 }
 362                 kdb_nextline = 1; /* reset output line number */
 363                 break;
 364         default:
 365                 if (key >= 32 && lastchar < bufend) {
 366                         if (cp < lastchar) {
 367                                 memcpy(tmpbuffer, cp, lastchar - cp);
 368                                 memcpy(cp+1, tmpbuffer, lastchar - cp);
 369                                 *++lastchar = '\0';
 370                                 *cp = key;
 371                                 kdb_printf("%s\r", cp);
 372                                 ++cp;
 373                                 tmp = *cp;
 374                                 *cp = '\0';
 375                                 kdb_printf(kdb_prompt_str);
 376                                 kdb_printf("%s", buffer);
 377                                 *cp = tmp;
 378                         } else {
 379                                 *++lastchar = '\0';
 380                                 *cp++ = key;
 381                                 /* The kgdb transition check will hide
 382                                  * printed characters if we think that
 383                                  * kgdb is connecting, until the check
 384                                  * fails */
 385                                 if (!KDB_STATE(KGDB_TRANS))
 386                                         kgdb_transition_check(buffer);
 387                                 else
 388                                         kdb_printf("%c", key);
 389                         }
 390                         /* Special escape to kgdb */
 391                         if (lastchar - buffer >= 5 &&
 392                             strcmp(lastchar - 5, "$?#3f") == 0) {
 393                                 strcpy(buffer, "kgdb");
 394                                 KDB_STATE_SET(DOING_KGDB);
 395                                 return buffer;
 396                         }
 397                         if (lastchar - buffer >= 14 &&
 398                             strcmp(lastchar - 14, "$qSupported#37") == 0) {
 399                                 strcpy(buffer, "kgdb");
 400                                 KDB_STATE_SET(DOING_KGDB2);
 401                                 return buffer;
 402                         }
 403                 }
 404                 break;
 405         }
 406         goto poll_again;
 407 }
 408
 409 /*
 410  * kdb_getstr
 411  *
 412  *      Print the prompt string and read a command from the
 413  *      input device.
 414  *
 415  * Parameters:
 416  *      buffer  Address of buffer to receive command
 417  *      bufsize Size of buffer in bytes
 418  *      prompt  Pointer to string to use as prompt string
 419  * Returns:
 420  *      Pointer to command buffer.
 421  * Locking:
 422  *      None.
 423  * Remarks:
 424  *      For SMP kernels, the processor number will be
 425  *      substituted for %d, %x or %o in the prompt.
 426  */
 427
 428 char *kdb_getstr(char *buffer, size_t bufsize, char *prompt)
 429 {
 430         if (prompt && kdb_prompt_str != prompt)
 431                 strncpy(kdb_prompt_str, prompt, CMD_BUFLEN);
 432         kdb_printf(kdb_prompt_str);
 433         kdb_nextline = 1;       /* Prompt and input resets line number */
 434         return kdb_read(buffer, bufsize);
 435 }
 436
 437 /*
 438  * kdb_input_flush
 439  *
 440  *      Get rid of any buffered console input.
 441  *
 442  * Parameters:
 443  *      none
 444  * Returns:
 445  *      nothing
 446  * Locking:
 447  *      none
 448  * Remarks:
 449  *      Call this function whenever you want to flush input.  If there is any
 450  *      outstanding input, it ignores all characters until there has been no
 451  *      data for approximately 1ms.
 452  */
 453
 454 static void kdb_input_flush(void)
 455 {
 456         get_char_func *f;
 457         int res;
 458         int flush_delay = 1;
 459         while (flush_delay) {
 460                 flush_delay--;
 461 empty:
 462                 touch_nmi_watchdog();
 463                 for (f = &kdb_poll_funcs[0]; *f; ++f) {
 464                         res = (*f)();
 465                         if (res != -1) {
 466                                 flush_delay = 1;
 467                                 goto empty;
 468                         }
 469                 }
 470                 if (flush_delay)
 471                         mdelay(1);
 472         }
 473 }
 474
 475 /*
 476  * kdb_printf
 477  *
 478  *      Print a string to the output device(s).
 479  *
 480  * Parameters:
 481  *      printf-like format and optional args.
 482  * Returns:
 483  *      0
 484  * Locking:
 485  *      None.
 486  * Remarks:
 487  *      use 'kdbcons->write()' to avoid polluting 'log_buf' with
 488  *      kdb output.
 489  *
 490  *  If the user is doing a cmd args | grep srch
 491  *  then kdb_grepping_flag is set.
 492  *  In that case we need to accumulate full lines (ending in \n) before
 493  *  searching for the pattern.
 494  */
 495
 496 static char kdb_buffer[256];    /* A bit too big to go on stack */
 497 static char *next_avail = kdb_buffer;
 498 static int  size_avail;
 499 static int  suspend_grep;
 500
 501 /*
 502  * search arg1 to see if it contains arg2
 503  * (kdmain.c provides flags for ^pat and pat$)
 504  *
 505  * return 1 for found, 0 for not found
 506  */
 507 static int kdb_search_string(char *searched, char *searchfor)
 508 {
 509         char firstchar, *cp;
 510         int len1, len2;
 511
 512         /* not counting the newline at the end of "searched" */
 513         len1 = strlen(searched)-1;
 514         len2 = strlen(searchfor);
 515         if (len1 < len2)
 516                 return 0;
 517         if (kdb_grep_leading && kdb_grep_trailing && len1 != len2)
 518                 return 0;
 519         if (kdb_grep_leading) {
 520                 if (!strncmp(searched, searchfor, len2))
 521                         return 1;
 522         } else if (kdb_grep_trailing) {
 523                 if (!strncmp(searched+len1-len2, searchfor, len2))
 524                         return 1;
 525         } else {
 526                 firstchar = *searchfor;
 527                 cp = searched;
 528                 while ((cp = strchr(cp, firstchar))) {
 529                         if (!strncmp(cp, searchfor, len2))
 530                                 return 1;
 531                         cp++;
 532                 }
 533         }
 534         return 0;
 535 }
 536
 537 int vkdb_printf(const char *fmt, va_list ap)
 538 {
 539         int diag;
 540         int linecount;
 541         int logging, saved_loglevel = 0;
 542         int saved_trap_printk;
 543         int got_printf_lock = 0;
 544         int retlen = 0;
 545         int fnd, len;
 546         char *cp, *cp2, *cphold = NULL, replaced_byte = ' ';
 547         char *moreprompt = "more> ";
 548         struct console *c = console_drivers;
 549         static DEFINE_SPINLOCK(kdb_printf_lock);
 550         unsigned long uninitialized_var(flags);
 551
 552         preempt_disable();
 553         saved_trap_printk = kdb_trap_printk;
 554         kdb_trap_printk = 0;
 555
 556         /* Serialize kdb_printf if multiple cpus try to write at once.
 557          * But if any cpu goes recursive in kdb, just print the output,
 558          * even if it is interleaved with any other text.
 559          */
 560         if (!KDB_STATE(PRINTF_LOCK)) {
 561                 KDB_STATE_SET(PRINTF_LOCK);
 562                 spin_lock_irqsave(&kdb_printf_lock, flags);
 563                 got_printf_lock = 1;
 564                 atomic_inc(&kdb_event);
 565         } else {
 566                 __acquire(kdb_printf_lock);
 567         }
 568
 569         diag = kdbgetintenv("LINES", &linecount);
 570         if (diag || linecount <= 1)
 571                 linecount = 24;
 572
 573         diag = kdbgetintenv("LOGGING", &logging);
 574         if (diag)
 575                 logging = 0;
 576
 577         if (!kdb_grepping_flag || suspend_grep) {
 578                 /* normally, every vsnprintf starts a new buffer */
 579                 next_avail = kdb_buffer;
 580                 size_avail = sizeof(kdb_buffer);
 581         }
 582         vsnprintf(next_avail, size_avail, fmt, ap);
 583
 584         /*
 585          * If kdb_parse() found that the command was cmd xxx | grep yyy
 586          * then kdb_grepping_flag is set, and kdb_grep_string contains yyy
 587          *
 588          * Accumulate the print data up to a newline before searching it.
 589          * (vsnprintf does null-terminate the string that it generates)
 590          */
 591
 592         /* skip the search if prints are temporarily unconditional */
 593         if (!suspend_grep && kdb_grepping_flag) {
 594                 cp = strchr(kdb_buffer, '\n');
 595                 if (!cp) {
 596                         /*
 597                          * Special cases that don't end with newlines
 598                          * but should be written without one:
 599                          *   The "[nn]kdb> " prompt should
 600                          *   appear at the front of the buffer.
 601                          *
 602                          *   The "[nn]more " prompt should also be
 603                          *     (MOREPROMPT -> moreprompt)
 604                          *   written *   but we print that ourselves,
 605                          *   we set the suspend_grep flag to make
 606                          *   it unconditional.
 607                          *
 608                          */
 609                         if (next_avail == kdb_buffer) {
 610                                 /*
 611                                  * these should occur after a newline,
 612                                  * so they will be at the front of the
 613                                  * buffer
 614                                  */
 615                                 cp2 = kdb_buffer;
 616                                 len = strlen(kdb_prompt_str);
 617                                 if (!strncmp(cp2, kdb_prompt_str, len)) {
 618                                         /*
 619                                          * We're about to start a new
 620                                          * command, so we can go back
 621                                          * to normal mode.
 622                                          */
 623                                         kdb_grepping_flag = 0;
 624                                         goto kdb_printit;
 625                                 }
 626                         }
 627                         /* no newline; don't search/write the buffer
 628                            until one is there */
 629                         len = strlen(kdb_buffer);
 630                         next_avail = kdb_buffer + len;
 631                         size_avail = sizeof(kdb_buffer) - len;
 632                         goto kdb_print_out;
 633                 }
 634
 635                 /*
 636                  * The newline is present; print through it or discard
 637                  * it, depending on the results of the search.
 638                  */
 639                 cp++;                /* to byte after the newline */
 640                 replaced_byte = *cp; /* remember what/where it was */
 641                 cphold = cp;
 642                 *cp = '\0';          /* end the string for our search */
 643
 644                 /*
 645                  * We now have a newline at the end of the string
 646                  * Only continue with this output if it contains the
 647                  * search string.
 648                  */
 649                 fnd = kdb_search_string(kdb_buffer, kdb_grep_string);
 650                 if (!fnd) {
 651                         /*
 652                          * At this point the complete line at the start
 653                          * of kdb_buffer can be discarded, as it does
 654                          * not contain what the user is looking for.
 655                          * Shift the buffer left.
 656                          */
 657                         *cphold = replaced_byte;
 658                         strcpy(kdb_buffer, cphold);
 659                         len = strlen(kdb_buffer);
 660                         next_avail = kdb_buffer + len;
 661                         size_avail = sizeof(kdb_buffer) - len;
 662                         goto kdb_print_out;
 663                 }
 664                 /*
 665                  * at this point the string is a full line and
 666                  * should be printed, up to the null.
 667                  */
 668         }
 669 kdb_printit:
 670
 671         /*
 672          * Write to all consoles.
 673          */
 674         retlen = strlen(kdb_buffer);
 675         if (!dbg_kdb_mode && kgdb_connected) {
 676                 gdbstub_msg_write(kdb_buffer, retlen);
 677         } else {
 678                 if (!dbg_io_ops->is_console) {
 679                         len = strlen(kdb_buffer);
 680                         cp = kdb_buffer;
 681                         while (len--) {
 682                                 dbg_io_ops->write_char(*cp);
 683                                 cp++;
 684                         }
 685                 }
 686                 while (c) {
 687                         c->write(c, kdb_buffer, retlen);
 688                         touch_nmi_watchdog();
 689                         c = c->next;
 690                 }
 691         }
 692         if (logging) {
 693                 saved_loglevel = console_loglevel;
 694                 console_loglevel = 0;
 695                 printk(KERN_INFO "%s", kdb_buffer);
 696         }
 697
 698         if (KDB_STATE(PAGER) && strchr(kdb_buffer, '\n'))
 699                 kdb_nextline++;
 700
 701         /* check for having reached the LINES number of printed lines */
 702         if (kdb_nextline == linecount) {
 703                 char buf1[16] = "";
 704 #if defined(CONFIG_SMP)
 705                 char buf2[32];
 706 #endif
 707
 708                 /* Watch out for recursion here.  Any routine that calls
 709                  * kdb_printf will come back through here.  And kdb_read
 710                  * uses kdb_printf to echo on serial consoles ...
 711                  */
 712                 kdb_nextline = 1;       /* In case of recursion */
 713
 714                 /*
 715                  * Pause until cr.
 716                  */
 717                 moreprompt = kdbgetenv("MOREPROMPT");
 718                 if (moreprompt == NULL)
 719                         moreprompt = "more> ";
 720
 721 #if defined(CONFIG_SMP)
 722                 if (strchr(moreprompt, '%')) {
 723                         sprintf(buf2, moreprompt, get_cpu());
 724                         put_cpu();
 725                         moreprompt = buf2;
 726                 }
 727 #endif
 728
 729                 kdb_input_flush();
 730                 c = console_drivers;
 731
 732                 if (!dbg_io_ops->is_console) {
 733                         len = strlen(moreprompt);
 734                         cp = moreprompt;
 735                         while (len--) {
 736                                 dbg_io_ops->write_char(*cp);
 737                                 cp++;
 738                         }
 739                 }
 740                 while (c) {
 741                         c->write(c, moreprompt, strlen(moreprompt));
 742                         touch_nmi_watchdog();
 743                         c = c->next;
 744                 }
 745
 746                 if (logging)
 747                         printk("%s", moreprompt);
 748
 749                 kdb_read(buf1, 2); /* '2' indicates to return
 750                                     * immediately after getting one key. */
 751                 kdb_nextline = 1;       /* Really set output line 1 */
 752
 753                 /* empty and reset the buffer: */
 754                 kdb_buffer[0] = '\0';
 755                 next_avail = kdb_buffer;
 756                 size_avail = sizeof(kdb_buffer);
 757                 if ((buf1[0] == 'q') || (buf1[0] == 'Q')) {
 758                         /* user hit q or Q */
 759                         KDB_FLAG_SET(CMD_INTERRUPT); /* command interrupted */
 760                         KDB_STATE_CLEAR(PAGER);
 761                         /* end of command output; back to normal mode */
 762                         kdb_grepping_flag = 0;
 763                         kdb_printf("\n");
 764                 } else if (buf1[0] == ' ') {
 765                         kdb_printf("\n");
 766                         suspend_grep = 1; /* for this recursion */
 767                 } else if (buf1[0] == '\n') {
 768                         kdb_nextline = linecount - 1;
 769                         kdb_printf("\r");
 770                         suspend_grep = 1; /* for this recursion */
 771                 } else if (buf1[0] && buf1[0] != '\n') {
 772                         /* user hit something other than enter */
 773                         suspend_grep = 1; /* for this recursion */
 774                         kdb_printf("\nOnly 'q' or 'Q' are processed at more "
 775                                    "prompt, input ignored\n");
 776                 } else if (kdb_grepping_flag) {
 777                         /* user hit enter */
 778                         suspend_grep = 1; /* for this recursion */
 779                         kdb_printf("\n");
 780                 }
 781                 kdb_input_flush();
 782         }
 783
 784         /*
 785          * For grep searches, shift the printed string left.
 786          *  replaced_byte contains the character that was overwritten with
 787          *  the terminating null, and cphold points to the null.
 788          * Then adjust the notion of available space in the buffer.
 789          */
 790         if (kdb_grepping_flag && !suspend_grep) {
 791                 *cphold = replaced_byte;
 792                 strcpy(kdb_buffer, cphold);
 793                 len = strlen(kdb_buffer);
 794                 next_avail = kdb_buffer + len;
 795                 size_avail = sizeof(kdb_buffer) - len;
 796         }
 797
 798 kdb_print_out:
 799         suspend_grep = 0; /* end of what may have been a recursive call */
 800         if (logging)
 801                 console_loglevel = saved_loglevel;
 802         if (KDB_STATE(PRINTF_LOCK) && got_printf_lock) {
 803                 got_printf_lock = 0;
 804                 spin_unlock_irqrestore(&kdb_printf_lock, flags);
 805                 KDB_STATE_CLEAR(PRINTF_LOCK);
 806                 atomic_dec(&kdb_event);
 807         } else {
 808                 __release(kdb_printf_lock);
 809         }
 810         kdb_trap_printk = saved_trap_printk;
 811         preempt_enable();
 812         return retlen;
 813 }
 814
 815 int kdb_printf(const char *fmt, ...)
 816 {
 817         va_list ap;
 818         int r;
 819
 820         va_start(ap, fmt);
 821         r = vkdb_printf(fmt, ap);
 822         va_end(ap);
 823
 824         return r;
 825 }
 826 EXPORT_SYMBOL_GPL(kdb_printf);