2 * Kernel Debugger Architecture Independent Console I/O handler
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
8 * Copyright (c) 1999-2006 Silicon Graphics, Inc. All Rights Reserved.
9 * Copyright (c) 2009 Wind River Systems, Inc. All Rights Reserved.
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"
29 #define CMD_BUFLEN 256
30 char kdb_prompt_str[CMD_BUFLEN];
33 int kdb_printf_cpu = -1;
35 static int kgdb_transition_check(char *buffer)
37 if (buffer[0] != '+' && buffer[0] != '$') {
38 KDB_STATE_SET(KGDB_TRANS);
39 kdb_printf("%s", buffer);
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);
53 * kdb_handle_escape() - validity check on an accumulated escape sequence.
54 * @buf: Accumulated escape characters to be examined. Note that buf
55 * is not a string, it is an array of characters and need not be
57 * @sz: Number of accumulated escape characters.
59 * Return: -1 if the escape sequence is unwanted, 0 if it is incomplete,
60 * otherwise it returns a mapped key value to pass to the upper layers.
62 static int kdb_handle_escape(char *buf, size_t sz)
64 char *lastkey = buf + sz - 1;
72 case 2: /* \e<something> */
79 case 'A': /* \e[A, up arrow */
81 case 'B': /* \e[B, down arrow */
83 case 'C': /* \e[C, right arrow */
85 case 'D': /* \e[D, left arrow */
87 case '1': /* \e[<1,3,4>], may be home, del, end */
95 if (*lastkey == '~') {
97 case '1': /* \e[1~, home */
99 case '3': /* \e[3~, del */
101 case '4': /* \e[4~, end */
112 * kdb_getchar() - Read a single character from a kdb console (or consoles).
114 * Other than polling the various consoles that are currently enabled,
115 * most of the work done in this function is dealing with escape sequences.
117 * An escape key could be the start of a vt100 control sequence such as \e[D
118 * (left arrow) or it could be a character in its own right. The standard
119 * method for detecting the difference is to wait for 2 seconds to see if there
120 * are any other characters. kdb is complicated by the lack of a timer service
121 * (interrupts are off), by multiple input sources. Escape sequence processing
122 * has to be done as states in the polling loop.
124 * Return: The key pressed or a control code derived from an escape sequence.
126 char kdb_getchar(void)
128 #define ESCAPE_UDELAY 1000
129 #define ESCAPE_DELAY (2*1000000/ESCAPE_UDELAY) /* 2 seconds worth of udelays */
130 char buf[4]; /* longest vt100 escape sequence is 4 bytes */
132 int escape_delay = 0;
133 get_char_func *f, *f_prev = NULL;
136 for (f = &kdb_poll_funcs[0]; ; ++f) {
138 /* Reset NMI watchdog once per poll loop */
139 touch_nmi_watchdog();
140 f = &kdb_poll_funcs[0];
146 udelay(ESCAPE_UDELAY);
147 if (--escape_delay == 0)
154 * When the first character is received (or we get a change
155 * input source) we set ourselves up to handle an escape
156 * sequences (just in case).
161 escape_delay = ESCAPE_DELAY;
165 key = kdb_handle_escape(buf, pbuf - buf);
166 if (key < 0) /* no escape sequence; return best character */
167 return buf[pbuf - buf == 2 ? 1 : 0];
178 * This function reads a string of characters, terminated by
179 * a newline, or by reaching the end of the supplied buffer,
180 * from the current kernel debugger console device.
182 * buffer - Address of character buffer to receive input characters.
183 * bufsize - size, in bytes, of the character buffer
185 * Returns a pointer to the buffer containing the received
186 * character string. This string will be terminated by a
189 * No locks are required to be held upon entry to this
190 * function. It is not reentrant - it relies on the fact
191 * that while kdb is running on only one "master debug" cpu.
193 * The buffer size must be >= 2.
196 static char *kdb_read(char *buffer, size_t bufsize)
199 char *bufend = buffer+bufsize-2; /* Reserve space for newline
204 static char tmpbuffer[CMD_BUFLEN];
205 int len = strlen(buffer);
210 int diag, dtab_count;
211 int key, buf_size, ret;
214 diag = kdbgetintenv("DTABCOUNT", &dtab_count);
220 if (*(buffer+len-1) == '\n')
226 kdb_printf("%s", buffer);
232 case 8: /* backspace */
235 memcpy(tmpbuffer, cp, lastchar - cp);
236 memcpy(cp-1, tmpbuffer, lastchar - cp);
238 *(--lastchar) = '\0';
240 kdb_printf("\b%s \r", cp);
243 kdb_printf(kdb_prompt_str);
244 kdb_printf("%s", buffer);
251 if (!KDB_STATE(KGDB_TRANS)) {
252 KDB_STATE_SET(KGDB_TRANS);
253 kdb_printf("%s", buffer);
259 memcpy(tmpbuffer, cp+1, lastchar - cp - 1);
260 memcpy(cp, tmpbuffer, lastchar - cp - 1);
261 *(--lastchar) = '\0';
262 kdb_printf("%s \r", cp);
265 kdb_printf(kdb_prompt_str);
266 kdb_printf("%s", buffer);
273 kdb_printf(kdb_prompt_str);
279 kdb_printf("%s", cp);
290 memset(tmpbuffer, ' ',
291 strlen(kdb_prompt_str) + (lastchar-buffer));
292 *(tmpbuffer+strlen(kdb_prompt_str) +
293 (lastchar-buffer)) = '\0';
294 kdb_printf("\r%s\r", tmpbuffer);
295 *lastchar = (char)key;
296 *(lastchar+1) = '\0';
300 kdb_printf("%c", *cp);
305 memset(tmpbuffer, ' ',
306 strlen(kdb_prompt_str) + (lastchar-buffer));
307 *(tmpbuffer+strlen(kdb_prompt_str) +
308 (lastchar-buffer)) = '\0';
309 kdb_printf("\r%s\r", tmpbuffer);
310 *lastchar = (char)key;
311 *(lastchar+1) = '\0';
317 while (*p_tmp == ' ')
321 memcpy(tmpbuffer, p_tmp, cp-p_tmp);
322 *(tmpbuffer + (cp-p_tmp)) = '\0';
323 p_tmp = strrchr(tmpbuffer, ' ');
329 buf_size = sizeof(tmpbuffer) - (p_tmp - tmpbuffer);
330 count = kallsyms_symbol_complete(p_tmp, buf_size);
331 if (tab == 2 && count > 0) {
332 kdb_printf("\n%d symbols are found.", count);
333 if (count > dtab_count) {
335 kdb_printf(" But only first %d symbols will"
336 " be printed.\nYou can change the"
337 " environment variable DTABCOUNT.",
341 for (i = 0; i < count; i++) {
342 ret = kallsyms_symbol_next(p_tmp, i, buf_size);
346 kdb_printf("%s ", p_tmp);
348 kdb_printf("%s... ", p_tmp);
349 *(p_tmp + len) = '\0';
354 kdb_printf(kdb_prompt_str);
355 kdb_printf("%s", buffer);
356 } else if (tab != 2 && count > 0) {
357 len_tmp = strlen(p_tmp);
358 strncpy(p_tmp+len_tmp, cp, lastchar-cp+1);
359 len_tmp = strlen(p_tmp);
360 strncpy(cp, p_tmp+len, len_tmp-len + 1);
362 kdb_printf("%s", cp);
366 kdb_nextline = 1; /* reset output line number */
369 if (key >= 32 && lastchar < bufend) {
371 memcpy(tmpbuffer, cp, lastchar - cp);
372 memcpy(cp+1, tmpbuffer, lastchar - cp);
375 kdb_printf("%s\r", cp);
379 kdb_printf(kdb_prompt_str);
380 kdb_printf("%s", buffer);
385 /* The kgdb transition check will hide
386 * printed characters if we think that
387 * kgdb is connecting, until the check
389 if (!KDB_STATE(KGDB_TRANS)) {
390 if (kgdb_transition_check(buffer))
393 kdb_printf("%c", key);
396 /* Special escape to kgdb */
397 if (lastchar - buffer >= 5 &&
398 strcmp(lastchar - 5, "$?#3f") == 0) {
399 kdb_gdb_state_pass(lastchar - 5);
400 strcpy(buffer, "kgdb");
401 KDB_STATE_SET(DOING_KGDB);
404 if (lastchar - buffer >= 11 &&
405 strcmp(lastchar - 11, "$qSupported") == 0) {
406 kdb_gdb_state_pass(lastchar - 11);
407 strcpy(buffer, "kgdb");
408 KDB_STATE_SET(DOING_KGDB);
420 * Print the prompt string and read a command from the
424 * buffer Address of buffer to receive command
425 * bufsize Size of buffer in bytes
426 * prompt Pointer to string to use as prompt string
428 * Pointer to command buffer.
432 * For SMP kernels, the processor number will be
433 * substituted for %d, %x or %o in the prompt.
436 char *kdb_getstr(char *buffer, size_t bufsize, const char *prompt)
438 if (prompt && kdb_prompt_str != prompt)
439 strscpy(kdb_prompt_str, prompt, CMD_BUFLEN);
440 kdb_printf(kdb_prompt_str);
441 kdb_nextline = 1; /* Prompt and input resets line number */
442 return kdb_read(buffer, bufsize);
448 * Get rid of any buffered console input.
457 * Call this function whenever you want to flush input. If there is any
458 * outstanding input, it ignores all characters until there has been no
459 * data for approximately 1ms.
462 static void kdb_input_flush(void)
467 while (flush_delay) {
470 touch_nmi_watchdog();
471 for (f = &kdb_poll_funcs[0]; *f; ++f) {
486 * Print a string to the output device(s).
489 * printf-like format and optional args.
495 * use 'kdbcons->write()' to avoid polluting 'log_buf' with
498 * If the user is doing a cmd args | grep srch
499 * then kdb_grepping_flag is set.
500 * In that case we need to accumulate full lines (ending in \n) before
501 * searching for the pattern.
504 static char kdb_buffer[256]; /* A bit too big to go on stack */
505 static char *next_avail = kdb_buffer;
506 static int size_avail;
507 static int suspend_grep;
510 * search arg1 to see if it contains arg2
511 * (kdmain.c provides flags for ^pat and pat$)
513 * return 1 for found, 0 for not found
515 static int kdb_search_string(char *searched, char *searchfor)
520 /* not counting the newline at the end of "searched" */
521 len1 = strlen(searched)-1;
522 len2 = strlen(searchfor);
525 if (kdb_grep_leading && kdb_grep_trailing && len1 != len2)
527 if (kdb_grep_leading) {
528 if (!strncmp(searched, searchfor, len2))
530 } else if (kdb_grep_trailing) {
531 if (!strncmp(searched+len1-len2, searchfor, len2))
534 firstchar = *searchfor;
536 while ((cp = strchr(cp, firstchar))) {
537 if (!strncmp(cp, searchfor, len2))
545 static void kdb_msg_write(const char *msg, int msg_len)
558 dbg_io_ops->write_char(*cp);
562 for_each_console(c) {
563 if (!(c->flags & CON_ENABLED))
565 if (c == dbg_io_ops->cons)
568 * Set oops_in_progress to encourage the console drivers to
569 * disregard their internal spin locks: in the current calling
570 * context the risk of deadlock is a bigger problem than risks
571 * due to re-entering the console driver. We operate directly on
572 * oops_in_progress rather than using bust_spinlocks() because
573 * the calls bust_spinlocks() makes on exit are not appropriate
574 * for this calling context.
577 c->write(c, msg, msg_len);
579 touch_nmi_watchdog();
583 int vkdb_printf(enum kdb_msgsrc src, const char *fmt, va_list ap)
588 int logging, saved_loglevel = 0;
591 int this_cpu, old_cpu;
592 char *cp, *cp2, *cphold = NULL, replaced_byte = ' ';
593 char *moreprompt = "more> ";
596 /* Serialize kdb_printf if multiple cpus try to write at once.
597 * But if any cpu goes recursive in kdb, just print the output,
598 * even if it is interleaved with any other text.
600 local_irq_save(flags);
601 this_cpu = smp_processor_id();
603 old_cpu = cmpxchg(&kdb_printf_cpu, -1, this_cpu);
604 if (old_cpu == -1 || old_cpu == this_cpu)
610 diag = kdbgetintenv("LINES", &linecount);
611 if (diag || linecount <= 1)
614 diag = kdbgetintenv("COLUMNS", &colcount);
615 if (diag || colcount <= 1)
618 diag = kdbgetintenv("LOGGING", &logging);
622 if (!kdb_grepping_flag || suspend_grep) {
623 /* normally, every vsnprintf starts a new buffer */
624 next_avail = kdb_buffer;
625 size_avail = sizeof(kdb_buffer);
627 vsnprintf(next_avail, size_avail, fmt, ap);
630 * If kdb_parse() found that the command was cmd xxx | grep yyy
631 * then kdb_grepping_flag is set, and kdb_grep_string contains yyy
633 * Accumulate the print data up to a newline before searching it.
634 * (vsnprintf does null-terminate the string that it generates)
637 /* skip the search if prints are temporarily unconditional */
638 if (!suspend_grep && kdb_grepping_flag) {
639 cp = strchr(kdb_buffer, '\n');
642 * Special cases that don't end with newlines
643 * but should be written without one:
644 * The "[nn]kdb> " prompt should
645 * appear at the front of the buffer.
647 * The "[nn]more " prompt should also be
648 * (MOREPROMPT -> moreprompt)
649 * written * but we print that ourselves,
650 * we set the suspend_grep flag to make
654 if (next_avail == kdb_buffer) {
656 * these should occur after a newline,
657 * so they will be at the front of the
661 len = strlen(kdb_prompt_str);
662 if (!strncmp(cp2, kdb_prompt_str, len)) {
664 * We're about to start a new
665 * command, so we can go back
668 kdb_grepping_flag = 0;
672 /* no newline; don't search/write the buffer
673 until one is there */
674 len = strlen(kdb_buffer);
675 next_avail = kdb_buffer + len;
676 size_avail = sizeof(kdb_buffer) - len;
681 * The newline is present; print through it or discard
682 * it, depending on the results of the search.
684 cp++; /* to byte after the newline */
685 replaced_byte = *cp; /* remember what/where it was */
687 *cp = '\0'; /* end the string for our search */
690 * We now have a newline at the end of the string
691 * Only continue with this output if it contains the
694 fnd = kdb_search_string(kdb_buffer, kdb_grep_string);
697 * At this point the complete line at the start
698 * of kdb_buffer can be discarded, as it does
699 * not contain what the user is looking for.
700 * Shift the buffer left.
702 *cphold = replaced_byte;
703 strcpy(kdb_buffer, cphold);
704 len = strlen(kdb_buffer);
705 next_avail = kdb_buffer + len;
706 size_avail = sizeof(kdb_buffer) - len;
709 if (kdb_grepping_flag >= KDB_GREPPING_FLAG_SEARCH) {
711 * This was a interactive search (using '/' at more
712 * prompt) and it has completed. Replace the \0 with
713 * its original value to ensure multi-line strings
714 * are handled properly, and return to normal mode.
716 *cphold = replaced_byte;
717 kdb_grepping_flag = 0;
720 * at this point the string is a full line and
721 * should be printed, up to the null.
727 * Write to all consoles.
729 retlen = strlen(kdb_buffer);
730 cp = (char *) printk_skip_headers(kdb_buffer);
731 if (!dbg_kdb_mode && kgdb_connected)
732 gdbstub_msg_write(cp, retlen - (cp - kdb_buffer));
734 kdb_msg_write(cp, retlen - (cp - kdb_buffer));
737 saved_loglevel = console_loglevel;
738 console_loglevel = CONSOLE_LOGLEVEL_SILENT;
739 if (printk_get_level(kdb_buffer) || src == KDB_MSGSRC_PRINTK)
740 printk("%s", kdb_buffer);
742 pr_info("%s", kdb_buffer);
745 if (KDB_STATE(PAGER)) {
747 * Check printed string to decide how to bump the
748 * kdb_nextline to control when the more prompt should
754 if (kdb_buffer[len] == '\n') {
757 } else if (kdb_buffer[len] == '\r') {
763 kdb_nextline += got / (colcount + 1);
766 /* check for having reached the LINES number of printed lines */
767 if (kdb_nextline >= linecount) {
770 /* Watch out for recursion here. Any routine that calls
771 * kdb_printf will come back through here. And kdb_read
772 * uses kdb_printf to echo on serial consoles ...
774 kdb_nextline = 1; /* In case of recursion */
779 moreprompt = kdbgetenv("MOREPROMPT");
780 if (moreprompt == NULL)
781 moreprompt = "more> ";
784 kdb_msg_write(moreprompt, strlen(moreprompt));
787 printk("%s", moreprompt);
790 kdb_nextline = 1; /* Really set output line 1 */
792 /* empty and reset the buffer: */
793 kdb_buffer[0] = '\0';
794 next_avail = kdb_buffer;
795 size_avail = sizeof(kdb_buffer);
796 if ((ch == 'q') || (ch == 'Q')) {
797 /* user hit q or Q */
798 KDB_FLAG_SET(CMD_INTERRUPT); /* command interrupted */
799 KDB_STATE_CLEAR(PAGER);
800 /* end of command output; back to normal mode */
801 kdb_grepping_flag = 0;
803 } else if (ch == ' ') {
805 suspend_grep = 1; /* for this recursion */
806 } else if (ch == '\n' || ch == '\r') {
807 kdb_nextline = linecount - 1;
809 suspend_grep = 1; /* for this recursion */
810 } else if (ch == '/' && !kdb_grepping_flag) {
812 kdb_getstr(kdb_grep_string, KDB_GREP_STRLEN,
813 kdbgetenv("SEARCHPROMPT") ?: "search> ");
814 *strchrnul(kdb_grep_string, '\n') = '\0';
815 kdb_grepping_flag += KDB_GREPPING_FLAG_SEARCH;
816 suspend_grep = 1; /* for this recursion */
818 /* user hit something unexpected */
819 suspend_grep = 1; /* for this recursion */
822 "\nOnly 'q', 'Q' or '/' are processed at "
823 "more prompt, input ignored\n");
825 kdb_printf("\n'/' cannot be used during | "
826 "grep filtering, input ignored\n");
827 } else if (kdb_grepping_flag) {
829 suspend_grep = 1; /* for this recursion */
836 * For grep searches, shift the printed string left.
837 * replaced_byte contains the character that was overwritten with
838 * the terminating null, and cphold points to the null.
839 * Then adjust the notion of available space in the buffer.
841 if (kdb_grepping_flag && !suspend_grep) {
842 *cphold = replaced_byte;
843 strcpy(kdb_buffer, cphold);
844 len = strlen(kdb_buffer);
845 next_avail = kdb_buffer + len;
846 size_avail = sizeof(kdb_buffer) - len;
850 suspend_grep = 0; /* end of what may have been a recursive call */
852 console_loglevel = saved_loglevel;
853 /* kdb_printf_cpu locked the code above. */
854 smp_store_release(&kdb_printf_cpu, old_cpu);
855 local_irq_restore(flags);
859 int kdb_printf(const char *fmt, ...)
865 r = vkdb_printf(KDB_MSGSRC_INTERNAL, fmt, ap);
870 EXPORT_SYMBOL_GPL(kdb_printf);