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 int kdb_printf_cpu = -1;
  34
  35 static int kgdb_transition_check(char *buffer)
  36 {
  37         if (buffer[0] != '+' && buffer[0] != '$') {
  38                 KDB_STATE_SET(KGDB_TRANS);
  39                 kdb_printf("%s", buffer);
  40         } else {
  41                 int slen = strlen(buffer);
  42                 if (slen > 3 && buffer[slen - 3] == '#') {
  43                         kdb_gdb_state_pass(buffer);
  44                         strcpy(buffer, "kgdb");
  45                         KDB_STATE_SET(DOING_KGDB);
  46                         return 1;
  47                 }
  48         }
  49         return 0;
  50 }
  51
  52 static int kdb_read_get_key(char *buffer, size_t bufsize)
  53 {
  54 #define ESCAPE_UDELAY 1000
  55 #define ESCAPE_DELAY (2*1000000/ESCAPE_UDELAY) /* 2 seconds worth of udelays */
  56         char escape_data[5];    /* longest vt100 escape sequence is 4 bytes */
  57         char *ped = escape_data;
  58         int escape_delay = 0;
  59         get_char_func *f, *f_escape = NULL;
  60         int key;
  61
  62         for (f = &kdb_poll_funcs[0]; ; ++f) {
  63                 if (*f == NULL) {
  64                         /* Reset NMI watchdog once per poll loop */
  65                         touch_nmi_watchdog();
  66                         f = &kdb_poll_funcs[0];
  67                 }
  68                 if (escape_delay == 2) {
  69                         *ped = '\0';
  70                         ped = escape_data;
  71                         --escape_delay;
  72                 }
  73                 if (escape_delay == 1) {
  74                         key = *ped++;
  75                         if (!*ped)
  76                                 --escape_delay;
  77                         break;
  78                 }
  79                 key = (*f)();
  80                 if (key == -1) {
  81                         if (escape_delay) {
  82                                 udelay(ESCAPE_UDELAY);
  83                                 --escape_delay;
  84                         }
  85                         continue;
  86                 }
  87                 if (bufsize <= 2) {
  88                         if (key == '\r')
  89                                 key = '\n';
  90                         *buffer++ = key;
  91                         *buffer = '\0';
  92                         return -1;
  93                 }
  94                 if (escape_delay == 0 && key == '\e') {
  95                         escape_delay = ESCAPE_DELAY;
  96                         ped = escape_data;
  97                         f_escape = f;
  98                 }
  99                 if (escape_delay) {
 100                         *ped++ = key;
 101                         if (f_escape != f) {
 102                                 escape_delay = 2;
 103                                 continue;
 104                         }
 105                         if (ped - escape_data == 1) {
 106                                 /* \e */
 107                                 continue;
 108                         } else if (ped - escape_data == 2) {
 109                                 /* \e<something> */
 110                                 if (key != '[')
 111                                         escape_delay = 2;
 112                                 continue;
 113                         } else if (ped - escape_data == 3) {
 114                                 /* \e[<something> */
 115                                 int mapkey = 0;
 116                                 switch (key) {
 117                                 case 'A': /* \e[A, up arrow */
 118                                         mapkey = 16;
 119                                         break;
 120                                 case 'B': /* \e[B, down arrow */
 121                                         mapkey = 14;
 122                                         break;
 123                                 case 'C': /* \e[C, right arrow */
 124                                         mapkey = 6;
 125                                         break;
 126                                 case 'D': /* \e[D, left arrow */
 127                                         mapkey = 2;
 128                                         break;
 129                                 case '1': /* dropthrough */
 130                                 case '3': /* dropthrough */
 131                                 /* \e[<1,3,4>], may be home, del, end */
 132                                 case '4':
 133                                         mapkey = -1;
 134                                         break;
 135                                 }
 136                                 if (mapkey != -1) {
 137                                         if (mapkey > 0) {
 138                                                 escape_data[0] = mapkey;
 139                                                 escape_data[1] = '\0';
 140                                         }
 141                                         escape_delay = 2;
 142                                 }
 143                                 continue;
 144                         } else if (ped - escape_data == 4) {
 145                                 /* \e[<1,3,4><something> */
 146                                 int mapkey = 0;
 147                                 if (key == '~') {
 148                                         switch (escape_data[2]) {
 149                                         case '1': /* \e[1~, home */
 150                                                 mapkey = 1;
 151                                                 break;
 152                                         case '3': /* \e[3~, del */
 153                                                 mapkey = 4;
 154                                                 break;
 155                                         case '4': /* \e[4~, end */
 156                                                 mapkey = 5;
 157                                                 break;
 158                                         }
 159                                 }
 160                                 if (mapkey > 0) {
 161                                         escape_data[0] = mapkey;
 162                                         escape_data[1] = '\0';
 163                                 }
 164                                 escape_delay = 2;
 165                                 continue;
 166                         }
 167                 }
 168                 break;  /* A key to process */
 169         }
 170         return key;
 171 }
 172
 173 /*
 174  * kdb_read
 175  *
 176  *      This function reads a string of characters, terminated by
 177  *      a newline, or by reaching the end of the supplied buffer,
 178  *      from the current kernel debugger console device.
 179  * Parameters:
 180  *      buffer  - Address of character buffer to receive input characters.
 181  *      bufsize - size, in bytes, of the character buffer
 182  * Returns:
 183  *      Returns a pointer to the buffer containing the received
 184  *      character string.  This string will be terminated by a
 185  *      newline character.
 186  * Locking:
 187  *      No locks are required to be held upon entry to this
 188  *      function.  It is not reentrant - it relies on the fact
 189  *      that while kdb is running on only one "master debug" cpu.
 190  * Remarks:
 191  *
 192  * The buffer size must be >= 2.  A buffer size of 2 means that the caller only
 193  * wants a single key.
 194  *
 195  * An escape key could be the start of a vt100 control sequence such as \e[D
 196  * (left arrow) or it could be a character in its own right.  The standard
 197  * method for detecting the difference is to wait for 2 seconds to see if there
 198  * are any other characters.  kdb is complicated by the lack of a timer service
 199  * (interrupts are off), by multiple input sources and by the need to sometimes
 200  * return after just one key.  Escape sequence processing has to be done as
 201  * states in the polling loop.
 202  */
 203
 204 static char *kdb_read(char *buffer, size_t bufsize)
 205 {
 206         char *cp = buffer;
 207         char *bufend = buffer+bufsize-2;        /* Reserve space for newline
 208                                                  * and null byte */
 209         char *lastchar;
 210         char *p_tmp;
 211         char tmp;
 212         static char tmpbuffer[CMD_BUFLEN];
 213         int len = strlen(buffer);
 214         int len_tmp;
 215         int tab = 0;
 216         int count;
 217         int i;
 218         int diag, dtab_count;
 219         int key;
 220
 221
 222         diag = kdbgetintenv("DTABCOUNT", &dtab_count);
 223         if (diag)
 224                 dtab_count = 30;
 225
 226         if (len > 0) {
 227                 cp += len;
 228                 if (*(buffer+len-1) == '\n')
 229                         cp--;
 230         }
 231
 232         lastchar = cp;
 233         *cp = '\0';
 234         kdb_printf("%s", buffer);
 235 poll_again:
 236         key = kdb_read_get_key(buffer, bufsize);
 237         if (key == -1)
 238                 return buffer;
 239         if (key != 9)
 240                 tab = 0;
 241         switch (key) {
 242         case 8: /* backspace */
 243                 if (cp > buffer) {
 244                         if (cp < lastchar) {
 245                                 memcpy(tmpbuffer, cp, lastchar - cp);
 246                                 memcpy(cp-1, tmpbuffer, lastchar - cp);
 247                         }
 248                         *(--lastchar) = '\0';
 249                         --cp;
 250                         kdb_printf("\b%s \r", cp);
 251                         tmp = *cp;
 252                         *cp = '\0';
 253                         kdb_printf(kdb_prompt_str);
 254                         kdb_printf("%s", buffer);
 255                         *cp = tmp;
 256                 }
 257                 break;
 258         case 13: /* enter */
 259                 *lastchar++ = '\n';
 260                 *lastchar++ = '\0';
 261                 if (!KDB_STATE(KGDB_TRANS)) {
 262                         KDB_STATE_SET(KGDB_TRANS);
 263                         kdb_printf("%s", buffer);
 264                 }
 265                 kdb_printf("\n");
 266                 return buffer;
 267         case 4: /* Del */
 268                 if (cp < lastchar) {
 269                         memcpy(tmpbuffer, cp+1, lastchar - cp - 1);
 270                         memcpy(cp, tmpbuffer, lastchar - cp - 1);
 271                         *(--lastchar) = '\0';
 272                         kdb_printf("%s \r", cp);
 273                         tmp = *cp;
 274                         *cp = '\0';
 275                         kdb_printf(kdb_prompt_str);
 276                         kdb_printf("%s", buffer);
 277                         *cp = tmp;
 278                 }
 279                 break;
 280         case 1: /* Home */
 281                 if (cp > buffer) {
 282                         kdb_printf("\r");
 283                         kdb_printf(kdb_prompt_str);
 284                         cp = buffer;
 285                 }
 286                 break;
 287         case 5: /* End */
 288                 if (cp < lastchar) {
 289                         kdb_printf("%s", cp);
 290                         cp = lastchar;
 291                 }
 292                 break;
 293         case 2: /* Left */
 294                 if (cp > buffer) {
 295                         kdb_printf("\b");
 296                         --cp;
 297                 }
 298                 break;
 299         case 14: /* Down */
 300                 memset(tmpbuffer, ' ',
 301                        strlen(kdb_prompt_str) + (lastchar-buffer));
 302                 *(tmpbuffer+strlen(kdb_prompt_str) +
 303                   (lastchar-buffer)) = '\0';
 304                 kdb_printf("\r%s\r", tmpbuffer);
 305                 *lastchar = (char)key;
 306                 *(lastchar+1) = '\0';
 307                 return lastchar;
 308         case 6: /* Right */
 309                 if (cp < lastchar) {
 310                         kdb_printf("%c", *cp);
 311                         ++cp;
 312                 }
 313                 break;
 314         case 16: /* Up */
 315                 memset(tmpbuffer, ' ',
 316                        strlen(kdb_prompt_str) + (lastchar-buffer));
 317                 *(tmpbuffer+strlen(kdb_prompt_str) +
 318                   (lastchar-buffer)) = '\0';
 319                 kdb_printf("\r%s\r", tmpbuffer);
 320                 *lastchar = (char)key;
 321                 *(lastchar+1) = '\0';
 322                 return lastchar;
 323         case 9: /* Tab */
 324                 if (tab < 2)
 325                         ++tab;
 326                 p_tmp = buffer;
 327                 while (*p_tmp == ' ')
 328                         p_tmp++;
 329                 if (p_tmp > cp)
 330                         break;
 331                 memcpy(tmpbuffer, p_tmp, cp-p_tmp);
 332                 *(tmpbuffer + (cp-p_tmp)) = '\0';
 333                 p_tmp = strrchr(tmpbuffer, ' ');
 334                 if (p_tmp)
 335                         ++p_tmp;
 336                 else
 337                         p_tmp = tmpbuffer;
 338                 len = strlen(p_tmp);
 339                 count = kallsyms_symbol_complete(p_tmp,
 340                                                  sizeof(tmpbuffer) -
 341                                                  (p_tmp - tmpbuffer));
 342                 if (tab == 2 && count > 0) {
 343                         kdb_printf("\n%d symbols are found.", count);
 344                         if (count > dtab_count) {
 345                                 count = dtab_count;
 346                                 kdb_printf(" But only first %d symbols will"
 347                                            " be printed.\nYou can change the"
 348                                            " environment variable DTABCOUNT.",
 349                                            count);
 350                         }
 351                         kdb_printf("\n");
 352                         for (i = 0; i < count; i++) {
 353                                 if (WARN_ON(!kallsyms_symbol_next(p_tmp, i)))
 354                                         break;
 355                                 kdb_printf("%s ", p_tmp);
 356                                 *(p_tmp + len) = '\0';
 357                         }
 358                         if (i >= dtab_count)
 359                                 kdb_printf("...");
 360                         kdb_printf("\n");
 361                         kdb_printf(kdb_prompt_str);
 362                         kdb_printf("%s", buffer);
 363                 } else if (tab != 2 && count > 0) {
 364                         len_tmp = strlen(p_tmp);
 365                         strncpy(p_tmp+len_tmp, cp, lastchar-cp+1);
 366                         len_tmp = strlen(p_tmp);
 367                         strncpy(cp, p_tmp+len, len_tmp-len + 1);
 368                         len = len_tmp - len;
 369                         kdb_printf("%s", cp);
 370                         cp += len;
 371                         lastchar += len;
 372                 }
 373                 kdb_nextline = 1; /* reset output line number */
 374                 break;
 375         default:
 376                 if (key >= 32 && lastchar < bufend) {
 377                         if (cp < lastchar) {
 378                                 memcpy(tmpbuffer, cp, lastchar - cp);
 379                                 memcpy(cp+1, tmpbuffer, lastchar - cp);
 380                                 *++lastchar = '\0';
 381                                 *cp = key;
 382                                 kdb_printf("%s\r", cp);
 383                                 ++cp;
 384                                 tmp = *cp;
 385                                 *cp = '\0';
 386                                 kdb_printf(kdb_prompt_str);
 387                                 kdb_printf("%s", buffer);
 388                                 *cp = tmp;
 389                         } else {
 390                                 *++lastchar = '\0';
 391                                 *cp++ = key;
 392                                 /* The kgdb transition check will hide
 393                                  * printed characters if we think that
 394                                  * kgdb is connecting, until the check
 395                                  * fails */
 396                                 if (!KDB_STATE(KGDB_TRANS)) {
 397                                         if (kgdb_transition_check(buffer))
 398                                                 return buffer;
 399                                 } else {
 400                                         kdb_printf("%c", key);
 401                                 }
 402                         }
 403                         /* Special escape to kgdb */
 404                         if (lastchar - buffer >= 5 &&
 405                             strcmp(lastchar - 5, "$?#3f") == 0) {
 406                                 kdb_gdb_state_pass(lastchar - 5);
 407                                 strcpy(buffer, "kgdb");
 408                                 KDB_STATE_SET(DOING_KGDB);
 409                                 return buffer;
 410                         }
 411                         if (lastchar - buffer >= 11 &&
 412                             strcmp(lastchar - 11, "$qSupported") == 0) {
 413                                 kdb_gdb_state_pass(lastchar - 11);
 414                                 strcpy(buffer, "kgdb");
 415                                 KDB_STATE_SET(DOING_KGDB);
 416                                 return buffer;
 417                         }
 418                 }
 419                 break;
 420         }
 421         goto poll_again;
 422 }
 423
 424 /*
 425  * kdb_getstr
 426  *
 427  *      Print the prompt string and read a command from the
 428  *      input device.
 429  *
 430  * Parameters:
 431  *      buffer  Address of buffer to receive command
 432  *      bufsize Size of buffer in bytes
 433  *      prompt  Pointer to string to use as prompt string
 434  * Returns:
 435  *      Pointer to command buffer.
 436  * Locking:
 437  *      None.
 438  * Remarks:
 439  *      For SMP kernels, the processor number will be
 440  *      substituted for %d, %x or %o in the prompt.
 441  */
 442
 443 char *kdb_getstr(char *buffer, size_t bufsize, const char *prompt)
 444 {
 445         if (prompt && kdb_prompt_str != prompt)
 446                 strncpy(kdb_prompt_str, prompt, CMD_BUFLEN);
 447         kdb_printf(kdb_prompt_str);
 448         kdb_nextline = 1;       /* Prompt and input resets line number */
 449         return kdb_read(buffer, bufsize);
 450 }
 451
 452 /*
 453  * kdb_input_flush
 454  *
 455  *      Get rid of any buffered console input.
 456  *
 457  * Parameters:
 458  *      none
 459  * Returns:
 460  *      nothing
 461  * Locking:
 462  *      none
 463  * Remarks:
 464  *      Call this function whenever you want to flush input.  If there is any
 465  *      outstanding input, it ignores all characters until there has been no
 466  *      data for approximately 1ms.
 467  */
 468
 469 static void kdb_input_flush(void)
 470 {
 471         get_char_func *f;
 472         int res;
 473         int flush_delay = 1;
 474         while (flush_delay) {
 475                 flush_delay--;
 476 empty:
 477                 touch_nmi_watchdog();
 478                 for (f = &kdb_poll_funcs[0]; *f; ++f) {
 479                         res = (*f)();
 480                         if (res != -1) {
 481                                 flush_delay = 1;
 482                                 goto empty;
 483                         }
 484                 }
 485                 if (flush_delay)
 486                         mdelay(1);
 487         }
 488 }
 489
 490 /*
 491  * kdb_printf
 492  *
 493  *      Print a string to the output device(s).
 494  *
 495  * Parameters:
 496  *      printf-like format and optional args.
 497  * Returns:
 498  *      0
 499  * Locking:
 500  *      None.
 501  * Remarks:
 502  *      use 'kdbcons->write()' to avoid polluting 'log_buf' with
 503  *      kdb output.
 504  *
 505  *  If the user is doing a cmd args | grep srch
 506  *  then kdb_grepping_flag is set.
 507  *  In that case we need to accumulate full lines (ending in \n) before
 508  *  searching for the pattern.
 509  */
 510
 511 static char kdb_buffer[256];    /* A bit too big to go on stack */
 512 static char *next_avail = kdb_buffer;
 513 static int  size_avail;
 514 static int  suspend_grep;
 515
 516 /*
 517  * search arg1 to see if it contains arg2
 518  * (kdmain.c provides flags for ^pat and pat$)
 519  *
 520  * return 1 for found, 0 for not found
 521  */
 522 static int kdb_search_string(char *searched, char *searchfor)
 523 {
 524         char firstchar, *cp;
 525         int len1, len2;
 526
 527         /* not counting the newline at the end of "searched" */
 528         len1 = strlen(searched)-1;
 529         len2 = strlen(searchfor);
 530         if (len1 < len2)
 531                 return 0;
 532         if (kdb_grep_leading && kdb_grep_trailing && len1 != len2)
 533                 return 0;
 534         if (kdb_grep_leading) {
 535                 if (!strncmp(searched, searchfor, len2))
 536                         return 1;
 537         } else if (kdb_grep_trailing) {
 538                 if (!strncmp(searched+len1-len2, searchfor, len2))
 539                         return 1;
 540         } else {
 541                 firstchar = *searchfor;
 542                 cp = searched;
 543                 while ((cp = strchr(cp, firstchar))) {
 544                         if (!strncmp(cp, searchfor, len2))
 545                                 return 1;
 546                         cp++;
 547                 }
 548         }
 549         return 0;
 550 }
 551
 552 int vkdb_printf(enum kdb_msgsrc src, const char *fmt, va_list ap)
 553 {
 554         int diag;
 555         int linecount;
 556         int colcount;
 557         int logging, saved_loglevel = 0;
 558         int retlen = 0;
 559         int fnd, len;
 560         int this_cpu, old_cpu;
 561         char *cp, *cp2, *cphold = NULL, replaced_byte = ' ';
 562         char *moreprompt = "more> ";
 563         struct console *c = console_drivers;
 564         unsigned long uninitialized_var(flags);
 565
 566         /* Serialize kdb_printf if multiple cpus try to write at once.
 567          * But if any cpu goes recursive in kdb, just print the output,
 568          * even if it is interleaved with any other text.
 569          */
 570         local_irq_save(flags);
 571         this_cpu = smp_processor_id();
 572         for (;;) {
 573                 old_cpu = cmpxchg(&kdb_printf_cpu, -1, this_cpu);
 574                 if (old_cpu == -1 || old_cpu == this_cpu)
 575                         break;
 576
 577                 cpu_relax();
 578         }
 579
 580         diag = kdbgetintenv("LINES", &linecount);
 581         if (diag || linecount <= 1)
 582                 linecount = 24;
 583
 584         diag = kdbgetintenv("COLUMNS", &colcount);
 585         if (diag || colcount <= 1)
 586                 colcount = 80;
 587
 588         diag = kdbgetintenv("LOGGING", &logging);
 589         if (diag)
 590                 logging = 0;
 591
 592         if (!kdb_grepping_flag || suspend_grep) {
 593                 /* normally, every vsnprintf starts a new buffer */
 594                 next_avail = kdb_buffer;
 595                 size_avail = sizeof(kdb_buffer);
 596         }
 597         vsnprintf(next_avail, size_avail, fmt, ap);
 598
 599         /*
 600          * If kdb_parse() found that the command was cmd xxx | grep yyy
 601          * then kdb_grepping_flag is set, and kdb_grep_string contains yyy
 602          *
 603          * Accumulate the print data up to a newline before searching it.
 604          * (vsnprintf does null-terminate the string that it generates)
 605          */
 606
 607         /* skip the search if prints are temporarily unconditional */
 608         if (!suspend_grep && kdb_grepping_flag) {
 609                 cp = strchr(kdb_buffer, '\n');
 610                 if (!cp) {
 611                         /*
 612                          * Special cases that don't end with newlines
 613                          * but should be written without one:
 614                          *   The "[nn]kdb> " prompt should
 615                          *   appear at the front of the buffer.
 616                          *
 617                          *   The "[nn]more " prompt should also be
 618                          *     (MOREPROMPT -> moreprompt)
 619                          *   written *   but we print that ourselves,
 620                          *   we set the suspend_grep flag to make
 621                          *   it unconditional.
 622                          *
 623                          */
 624                         if (next_avail == kdb_buffer) {
 625                                 /*
 626                                  * these should occur after a newline,
 627                                  * so they will be at the front of the
 628                                  * buffer
 629                                  */
 630                                 cp2 = kdb_buffer;
 631                                 len = strlen(kdb_prompt_str);
 632                                 if (!strncmp(cp2, kdb_prompt_str, len)) {
 633                                         /*
 634                                          * We're about to start a new
 635                                          * command, so we can go back
 636                                          * to normal mode.
 637                                          */
 638                                         kdb_grepping_flag = 0;
 639                                         goto kdb_printit;
 640                                 }
 641                         }
 642                         /* no newline; don't search/write the buffer
 643                            until one is there */
 644                         len = strlen(kdb_buffer);
 645                         next_avail = kdb_buffer + len;
 646                         size_avail = sizeof(kdb_buffer) - len;
 647                         goto kdb_print_out;
 648                 }
 649
 650                 /*
 651                  * The newline is present; print through it or discard
 652                  * it, depending on the results of the search.
 653                  */
 654                 cp++;                /* to byte after the newline */
 655                 replaced_byte = *cp; /* remember what/where it was */
 656                 cphold = cp;
 657                 *cp = '\0';          /* end the string for our search */
 658
 659                 /*
 660                  * We now have a newline at the end of the string
 661                  * Only continue with this output if it contains the
 662                  * search string.
 663                  */
 664                 fnd = kdb_search_string(kdb_buffer, kdb_grep_string);
 665                 if (!fnd) {
 666                         /*
 667                          * At this point the complete line at the start
 668                          * of kdb_buffer can be discarded, as it does
 669                          * not contain what the user is looking for.
 670                          * Shift the buffer left.
 671                          */
 672                         *cphold = replaced_byte;
 673                         strcpy(kdb_buffer, cphold);
 674                         len = strlen(kdb_buffer);
 675                         next_avail = kdb_buffer + len;
 676                         size_avail = sizeof(kdb_buffer) - len;
 677                         goto kdb_print_out;
 678                 }
 679                 if (kdb_grepping_flag >= KDB_GREPPING_FLAG_SEARCH)
 680                         /*
 681                          * This was a interactive search (using '/' at more
 682                          * prompt) and it has completed. Clear the flag.
 683                          */
 684                         kdb_grepping_flag = 0;
 685                 /*
 686                  * at this point the string is a full line and
 687                  * should be printed, up to the null.
 688                  */
 689         }
 690 kdb_printit:
 691
 692         /*
 693          * Write to all consoles.
 694          */
 695         retlen = strlen(kdb_buffer);
 696         cp = (char *) printk_skip_headers(kdb_buffer);
 697         if (!dbg_kdb_mode && kgdb_connected) {
 698                 gdbstub_msg_write(cp, retlen - (cp - kdb_buffer));
 699         } else {
 700                 if (dbg_io_ops && !dbg_io_ops->is_console) {
 701                         len = retlen - (cp - kdb_buffer);
 702                         cp2 = cp;
 703                         while (len--) {
 704                                 dbg_io_ops->write_char(*cp2);
 705                                 cp2++;
 706                         }
 707                 }
 708                 while (c) {
 709                         c->write(c, cp, retlen - (cp - kdb_buffer));
 710                         touch_nmi_watchdog();
 711                         c = c->next;
 712                 }
 713         }
 714         if (logging) {
 715                 saved_loglevel = console_loglevel;
 716                 console_loglevel = CONSOLE_LOGLEVEL_SILENT;
 717                 if (printk_get_level(kdb_buffer) || src == KDB_MSGSRC_PRINTK)
 718                         printk("%s", kdb_buffer);
 719                 else
 720                         pr_info("%s", kdb_buffer);
 721         }
 722
 723         if (KDB_STATE(PAGER)) {
 724                 /*
 725                  * Check printed string to decide how to bump the
 726                  * kdb_nextline to control when the more prompt should
 727                  * show up.
 728                  */
 729                 int got = 0;
 730                 len = retlen;
 731                 while (len--) {
 732                         if (kdb_buffer[len] == '\n') {
 733                                 kdb_nextline++;
 734                                 got = 0;
 735                         } else if (kdb_buffer[len] == '\r') {
 736                                 got = 0;
 737                         } else {
 738                                 got++;
 739                         }
 740                 }
 741                 kdb_nextline += got / (colcount + 1);
 742         }
 743
 744         /* check for having reached the LINES number of printed lines */
 745         if (kdb_nextline >= linecount) {
 746                 char buf1[16] = "";
 747
 748                 /* Watch out for recursion here.  Any routine that calls
 749                  * kdb_printf will come back through here.  And kdb_read
 750                  * uses kdb_printf to echo on serial consoles ...
 751                  */
 752                 kdb_nextline = 1;       /* In case of recursion */
 753
 754                 /*
 755                  * Pause until cr.
 756                  */
 757                 moreprompt = kdbgetenv("MOREPROMPT");
 758                 if (moreprompt == NULL)
 759                         moreprompt = "more> ";
 760
 761                 kdb_input_flush();
 762                 c = console_drivers;
 763
 764                 if (dbg_io_ops && !dbg_io_ops->is_console) {
 765                         len = strlen(moreprompt);
 766                         cp = moreprompt;
 767                         while (len--) {
 768                                 dbg_io_ops->write_char(*cp);
 769                                 cp++;
 770                         }
 771                 }
 772                 while (c) {
 773                         c->write(c, moreprompt, strlen(moreprompt));
 774                         touch_nmi_watchdog();
 775                         c = c->next;
 776                 }
 777
 778                 if (logging)
 779                         printk("%s", moreprompt);
 780
 781                 kdb_read(buf1, 2); /* '2' indicates to return
 782                                     * immediately after getting one key. */
 783                 kdb_nextline = 1;       /* Really set output line 1 */
 784
 785                 /* empty and reset the buffer: */
 786                 kdb_buffer[0] = '\0';
 787                 next_avail = kdb_buffer;
 788                 size_avail = sizeof(kdb_buffer);
 789                 if ((buf1[0] == 'q') || (buf1[0] == 'Q')) {
 790                         /* user hit q or Q */
 791                         KDB_FLAG_SET(CMD_INTERRUPT); /* command interrupted */
 792                         KDB_STATE_CLEAR(PAGER);
 793                         /* end of command output; back to normal mode */
 794                         kdb_grepping_flag = 0;
 795                         kdb_printf("\n");
 796                 } else if (buf1[0] == ' ') {
 797                         kdb_printf("\r");
 798                         suspend_grep = 1; /* for this recursion */
 799                 } else if (buf1[0] == '\n') {
 800                         kdb_nextline = linecount - 1;
 801                         kdb_printf("\r");
 802                         suspend_grep = 1; /* for this recursion */
 803                 } else if (buf1[0] == '/' && !kdb_grepping_flag) {
 804                         kdb_printf("\r");
 805                         kdb_getstr(kdb_grep_string, KDB_GREP_STRLEN,
 806                                    kdbgetenv("SEARCHPROMPT") ?: "search> ");
 807                         *strchrnul(kdb_grep_string, '\n') = '\0';
 808                         kdb_grepping_flag += KDB_GREPPING_FLAG_SEARCH;
 809                         suspend_grep = 1; /* for this recursion */
 810                 } else if (buf1[0] && buf1[0] != '\n') {
 811                         /* user hit something other than enter */
 812                         suspend_grep = 1; /* for this recursion */
 813                         if (buf1[0] != '/')
 814                                 kdb_printf(
 815                                     "\nOnly 'q', 'Q' or '/' are processed at "
 816                                     "more prompt, input ignored\n");
 817                         else
 818                                 kdb_printf("\n'/' cannot be used during | "
 819                                            "grep filtering, input ignored\n");
 820                 } else if (kdb_grepping_flag) {
 821                         /* user hit enter */
 822                         suspend_grep = 1; /* for this recursion */
 823                         kdb_printf("\n");
 824                 }
 825                 kdb_input_flush();
 826         }
 827
 828         /*
 829          * For grep searches, shift the printed string left.
 830          *  replaced_byte contains the character that was overwritten with
 831          *  the terminating null, and cphold points to the null.
 832          * Then adjust the notion of available space in the buffer.
 833          */
 834         if (kdb_grepping_flag && !suspend_grep) {
 835                 *cphold = replaced_byte;
 836                 strcpy(kdb_buffer, cphold);
 837                 len = strlen(kdb_buffer);
 838                 next_avail = kdb_buffer + len;
 839                 size_avail = sizeof(kdb_buffer) - len;
 840         }
 841
 842 kdb_print_out:
 843         suspend_grep = 0; /* end of what may have been a recursive call */
 844         if (logging)
 845                 console_loglevel = saved_loglevel;
 846         /* kdb_printf_cpu locked the code above. */
 847         smp_store_release(&kdb_printf_cpu, old_cpu);
 848         local_irq_restore(flags);
 849         return retlen;
 850 }
 851
 852 int kdb_printf(const char *fmt, ...)
 853 {
 854         va_list ap;
 855         int r;
 856
 857         va_start(ap, fmt);
 858         r = vkdb_printf(KDB_MSGSRC_INTERNAL, fmt, ap);
 859         va_end(ap);
 860
 861         return r;
 862 }
 863 EXPORT_SYMBOL_GPL(kdb_printf);