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
 30char kdb_prompt_str[CMD_BUFLEN];
 31
 32int kdb_trap_printk;
 
 33
 34static int kgdb_transition_check(char *buffer)
 35{
 36	if (buffer[0] != '+' && buffer[0] != '$') {
 37		KDB_STATE_SET(KGDB_TRANS);
 38		kdb_printf("%s", buffer);
 39	} else {
 40		int slen = strlen(buffer);
 41		if (slen > 3 && buffer[slen - 3] == '#') {
 42			kdb_gdb_state_pass(buffer);
 43			strcpy(buffer, "kgdb");
 44			KDB_STATE_SET(DOING_KGDB);
 45			return 1;
 46		}
 47	}
 48	return 0;
 49}
 50
 51static int kdb_read_get_key(char *buffer, size_t bufsize)
 52{
 53#define ESCAPE_UDELAY 1000
 54#define ESCAPE_DELAY (2*1000000/ESCAPE_UDELAY) /* 2 seconds worth of udelays */
 55	char escape_data[5];	/* longest vt100 escape sequence is 4 bytes */
 56	char *ped = escape_data;
 57	int escape_delay = 0;
 58	get_char_func *f, *f_escape = NULL;
 59	int key;
 60
 61	for (f = &kdb_poll_funcs[0]; ; ++f) {
 62		if (*f == NULL) {
 63			/* Reset NMI watchdog once per poll loop */
 64			touch_nmi_watchdog();
 65			f = &kdb_poll_funcs[0];
 66		}
 67		if (escape_delay == 2) {
 68			*ped = '\0';
 69			ped = escape_data;
 70			--escape_delay;
 71		}
 72		if (escape_delay == 1) {
 73			key = *ped++;
 74			if (!*ped)
 75				--escape_delay;
 76			break;
 77		}
 78		key = (*f)();
 79		if (key == -1) {
 80			if (escape_delay) {
 81				udelay(ESCAPE_UDELAY);
 82				--escape_delay;
 83			}
 84			continue;
 85		}
 86		if (bufsize <= 2) {
 87			if (key == '\r')
 88				key = '\n';
 89			*buffer++ = key;
 90			*buffer = '\0';
 91			return -1;
 92		}
 93		if (escape_delay == 0 && key == '\e') {
 94			escape_delay = ESCAPE_DELAY;
 95			ped = escape_data;
 96			f_escape = f;
 97		}
 98		if (escape_delay) {
 99			*ped++ = key;
100			if (f_escape != f) {
101				escape_delay = 2;
102				continue;
103			}
104			if (ped - escape_data == 1) {
105				/* \e */
106				continue;
107			} else if (ped - escape_data == 2) {
108				/* \e<something> */
109				if (key != '[')
110					escape_delay = 2;
111				continue;
112			} else if (ped - escape_data == 3) {
113				/* \e[<something> */
114				int mapkey = 0;
115				switch (key) {
116				case 'A': /* \e[A, up arrow */
117					mapkey = 16;
118					break;
119				case 'B': /* \e[B, down arrow */
120					mapkey = 14;
121					break;
122				case 'C': /* \e[C, right arrow */
123					mapkey = 6;
124					break;
125				case 'D': /* \e[D, left arrow */
126					mapkey = 2;
127					break;
128				case '1': /* dropthrough */
129				case '3': /* dropthrough */
130				/* \e[<1,3,4>], may be home, del, end */
131				case '4':
132					mapkey = -1;
133					break;
134				}
135				if (mapkey != -1) {
136					if (mapkey > 0) {
137						escape_data[0] = mapkey;
138						escape_data[1] = '\0';
139					}
140					escape_delay = 2;
141				}
142				continue;
143			} else if (ped - escape_data == 4) {
144				/* \e[<1,3,4><something> */
145				int mapkey = 0;
146				if (key == '~') {
147					switch (escape_data[2]) {
148					case '1': /* \e[1~, home */
149						mapkey = 1;
150						break;
151					case '3': /* \e[3~, del */
152						mapkey = 4;
153						break;
154					case '4': /* \e[4~, end */
155						mapkey = 5;
156						break;
157					}
158				}
159				if (mapkey > 0) {
160					escape_data[0] = mapkey;
161					escape_data[1] = '\0';
162				}
163				escape_delay = 2;
164				continue;
165			}
166		}
167		break;	/* A key to process */
168	}
169	return key;
170}
171
172/*
173 * kdb_read
174 *
175 *	This function reads a string of characters, terminated by
176 *	a newline, or by reaching the end of the supplied buffer,
177 *	from the current kernel debugger console device.
178 * Parameters:
179 *	buffer	- Address of character buffer to receive input characters.
180 *	bufsize - size, in bytes, of the character buffer
181 * Returns:
182 *	Returns a pointer to the buffer containing the received
183 *	character string.  This string will be terminated by a
184 *	newline character.
185 * Locking:
186 *	No locks are required to be held upon entry to this
187 *	function.  It is not reentrant - it relies on the fact
188 *	that while kdb is running on only one "master debug" cpu.
189 * Remarks:
190 *
191 * The buffer size must be >= 2.  A buffer size of 2 means that the caller only
192 * wants a single key.
193 *
194 * An escape key could be the start of a vt100 control sequence such as \e[D
195 * (left arrow) or it could be a character in its own right.  The standard
196 * method for detecting the difference is to wait for 2 seconds to see if there
197 * are any other characters.  kdb is complicated by the lack of a timer service
198 * (interrupts are off), by multiple input sources and by the need to sometimes
199 * return after just one key.  Escape sequence processing has to be done as
200 * states in the polling loop.
201 */
202
203static char *kdb_read(char *buffer, size_t bufsize)
204{
205	char *cp = buffer;
206	char *bufend = buffer+bufsize-2;	/* Reserve space for newline
207						 * and null byte */
208	char *lastchar;
209	char *p_tmp;
210	char tmp;
211	static char tmpbuffer[CMD_BUFLEN];
212	int len = strlen(buffer);
213	int len_tmp;
214	int tab = 0;
215	int count;
216	int i;
217	int diag, dtab_count;
218	int key;
219
220
221	diag = kdbgetintenv("DTABCOUNT", &dtab_count);
222	if (diag)
223		dtab_count = 30;
224
225	if (len > 0) {
226		cp += len;
227		if (*(buffer+len-1) == '\n')
228			cp--;
229	}
230
231	lastchar = cp;
232	*cp = '\0';
233	kdb_printf("%s", buffer);
234poll_again:
235	key = kdb_read_get_key(buffer, bufsize);
236	if (key == -1)
237		return buffer;
238	if (key != 9)
239		tab = 0;
240	switch (key) {
241	case 8: /* backspace */
242		if (cp > buffer) {
243			if (cp < lastchar) {
244				memcpy(tmpbuffer, cp, lastchar - cp);
245				memcpy(cp-1, tmpbuffer, lastchar - cp);
246			}
247			*(--lastchar) = '\0';
248			--cp;
249			kdb_printf("\b%s \r", cp);
250			tmp = *cp;
251			*cp = '\0';
252			kdb_printf(kdb_prompt_str);
253			kdb_printf("%s", buffer);
254			*cp = tmp;
255		}
256		break;
257	case 13: /* enter */
258		*lastchar++ = '\n';
259		*lastchar++ = '\0';
260		if (!KDB_STATE(KGDB_TRANS)) {
261			KDB_STATE_SET(KGDB_TRANS);
262			kdb_printf("%s", buffer);
263		}
264		kdb_printf("\n");
265		return buffer;
266	case 4: /* Del */
267		if (cp < lastchar) {
268			memcpy(tmpbuffer, cp+1, lastchar - cp - 1);
269			memcpy(cp, tmpbuffer, lastchar - cp - 1);
270			*(--lastchar) = '\0';
271			kdb_printf("%s \r", cp);
272			tmp = *cp;
273			*cp = '\0';
274			kdb_printf(kdb_prompt_str);
275			kdb_printf("%s", buffer);
276			*cp = tmp;
277		}
278		break;
279	case 1: /* Home */
280		if (cp > buffer) {
281			kdb_printf("\r");
282			kdb_printf(kdb_prompt_str);
283			cp = buffer;
284		}
285		break;
286	case 5: /* End */
287		if (cp < lastchar) {
288			kdb_printf("%s", cp);
289			cp = lastchar;
290		}
291		break;
292	case 2: /* Left */
293		if (cp > buffer) {
294			kdb_printf("\b");
295			--cp;
296		}
297		break;
298	case 14: /* Down */
299		memset(tmpbuffer, ' ',
300		       strlen(kdb_prompt_str) + (lastchar-buffer));
301		*(tmpbuffer+strlen(kdb_prompt_str) +
302		  (lastchar-buffer)) = '\0';
303		kdb_printf("\r%s\r", tmpbuffer);
304		*lastchar = (char)key;
305		*(lastchar+1) = '\0';
306		return lastchar;
307	case 6: /* Right */
308		if (cp < lastchar) {
309			kdb_printf("%c", *cp);
310			++cp;
311		}
312		break;
313	case 16: /* Up */
314		memset(tmpbuffer, ' ',
315		       strlen(kdb_prompt_str) + (lastchar-buffer));
316		*(tmpbuffer+strlen(kdb_prompt_str) +
317		  (lastchar-buffer)) = '\0';
318		kdb_printf("\r%s\r", tmpbuffer);
319		*lastchar = (char)key;
320		*(lastchar+1) = '\0';
321		return lastchar;
322	case 9: /* Tab */
323		if (tab < 2)
324			++tab;
325		p_tmp = buffer;
326		while (*p_tmp == ' ')
327			p_tmp++;
328		if (p_tmp > cp)
329			break;
330		memcpy(tmpbuffer, p_tmp, cp-p_tmp);
331		*(tmpbuffer + (cp-p_tmp)) = '\0';
332		p_tmp = strrchr(tmpbuffer, ' ');
333		if (p_tmp)
334			++p_tmp;
335		else
336			p_tmp = tmpbuffer;
337		len = strlen(p_tmp);
338		count = kallsyms_symbol_complete(p_tmp,
339						 sizeof(tmpbuffer) -
340						 (p_tmp - tmpbuffer));
341		if (tab == 2 && count > 0) {
342			kdb_printf("\n%d symbols are found.", count);
343			if (count > dtab_count) {
344				count = dtab_count;
345				kdb_printf(" But only first %d symbols will"
346					   " be printed.\nYou can change the"
347					   " environment variable DTABCOUNT.",
348					   count);
349			}
350			kdb_printf("\n");
351			for (i = 0; i < count; i++) {
352				if (kallsyms_symbol_next(p_tmp, i) < 0)
 
353					break;
354				kdb_printf("%s ", p_tmp);
 
 
 
355				*(p_tmp + len) = '\0';
356			}
357			if (i >= dtab_count)
358				kdb_printf("...");
359			kdb_printf("\n");
360			kdb_printf(kdb_prompt_str);
361			kdb_printf("%s", buffer);
362		} else if (tab != 2 && count > 0) {
363			len_tmp = strlen(p_tmp);
364			strncpy(p_tmp+len_tmp, cp, lastchar-cp+1);
365			len_tmp = strlen(p_tmp);
366			strncpy(cp, p_tmp+len, len_tmp-len + 1);
367			len = len_tmp - len;
368			kdb_printf("%s", cp);
369			cp += len;
370			lastchar += len;
371		}
372		kdb_nextline = 1; /* reset output line number */
373		break;
374	default:
375		if (key >= 32 && lastchar < bufend) {
376			if (cp < lastchar) {
377				memcpy(tmpbuffer, cp, lastchar - cp);
378				memcpy(cp+1, tmpbuffer, lastchar - cp);
379				*++lastchar = '\0';
380				*cp = key;
381				kdb_printf("%s\r", cp);
382				++cp;
383				tmp = *cp;
384				*cp = '\0';
385				kdb_printf(kdb_prompt_str);
386				kdb_printf("%s", buffer);
387				*cp = tmp;
388			} else {
389				*++lastchar = '\0';
390				*cp++ = key;
391				/* The kgdb transition check will hide
392				 * printed characters if we think that
393				 * kgdb is connecting, until the check
394				 * fails */
395				if (!KDB_STATE(KGDB_TRANS)) {
396					if (kgdb_transition_check(buffer))
397						return buffer;
398				} else {
399					kdb_printf("%c", key);
400				}
401			}
402			/* Special escape to kgdb */
403			if (lastchar - buffer >= 5 &&
404			    strcmp(lastchar - 5, "$?#3f") == 0) {
405				kdb_gdb_state_pass(lastchar - 5);
406				strcpy(buffer, "kgdb");
407				KDB_STATE_SET(DOING_KGDB);
408				return buffer;
409			}
410			if (lastchar - buffer >= 11 &&
411			    strcmp(lastchar - 11, "$qSupported") == 0) {
412				kdb_gdb_state_pass(lastchar - 11);
413				strcpy(buffer, "kgdb");
414				KDB_STATE_SET(DOING_KGDB);
415				return buffer;
416			}
417		}
418		break;
419	}
420	goto poll_again;
421}
422
423/*
424 * kdb_getstr
425 *
426 *	Print the prompt string and read a command from the
427 *	input device.
428 *
429 * Parameters:
430 *	buffer	Address of buffer to receive command
431 *	bufsize Size of buffer in bytes
432 *	prompt	Pointer to string to use as prompt string
433 * Returns:
434 *	Pointer to command buffer.
435 * Locking:
436 *	None.
437 * Remarks:
438 *	For SMP kernels, the processor number will be
439 *	substituted for %d, %x or %o in the prompt.
440 */
441
442char *kdb_getstr(char *buffer, size_t bufsize, const char *prompt)
443{
444	if (prompt && kdb_prompt_str != prompt)
445		strncpy(kdb_prompt_str, prompt, CMD_BUFLEN);
446	kdb_printf(kdb_prompt_str);
447	kdb_nextline = 1;	/* Prompt and input resets line number */
448	return kdb_read(buffer, bufsize);
449}
450
451/*
452 * kdb_input_flush
453 *
454 *	Get rid of any buffered console input.
455 *
456 * Parameters:
457 *	none
458 * Returns:
459 *	nothing
460 * Locking:
461 *	none
462 * Remarks:
463 *	Call this function whenever you want to flush input.  If there is any
464 *	outstanding input, it ignores all characters until there has been no
465 *	data for approximately 1ms.
466 */
467
468static void kdb_input_flush(void)
469{
470	get_char_func *f;
471	int res;
472	int flush_delay = 1;
473	while (flush_delay) {
474		flush_delay--;
475empty:
476		touch_nmi_watchdog();
477		for (f = &kdb_poll_funcs[0]; *f; ++f) {
478			res = (*f)();
479			if (res != -1) {
480				flush_delay = 1;
481				goto empty;
482			}
483		}
484		if (flush_delay)
485			mdelay(1);
486	}
487}
488
489/*
490 * kdb_printf
491 *
492 *	Print a string to the output device(s).
493 *
494 * Parameters:
495 *	printf-like format and optional args.
496 * Returns:
497 *	0
498 * Locking:
499 *	None.
500 * Remarks:
501 *	use 'kdbcons->write()' to avoid polluting 'log_buf' with
502 *	kdb output.
503 *
504 *  If the user is doing a cmd args | grep srch
505 *  then kdb_grepping_flag is set.
506 *  In that case we need to accumulate full lines (ending in \n) before
507 *  searching for the pattern.
508 */
509
510static char kdb_buffer[256];	/* A bit too big to go on stack */
511static char *next_avail = kdb_buffer;
512static int  size_avail;
513static int  suspend_grep;
514
515/*
516 * search arg1 to see if it contains arg2
517 * (kdmain.c provides flags for ^pat and pat$)
518 *
519 * return 1 for found, 0 for not found
520 */
521static int kdb_search_string(char *searched, char *searchfor)
522{
523	char firstchar, *cp;
524	int len1, len2;
525
526	/* not counting the newline at the end of "searched" */
527	len1 = strlen(searched)-1;
528	len2 = strlen(searchfor);
529	if (len1 < len2)
530		return 0;
531	if (kdb_grep_leading && kdb_grep_trailing && len1 != len2)
532		return 0;
533	if (kdb_grep_leading) {
534		if (!strncmp(searched, searchfor, len2))
535			return 1;
536	} else if (kdb_grep_trailing) {
537		if (!strncmp(searched+len1-len2, searchfor, len2))
538			return 1;
539	} else {
540		firstchar = *searchfor;
541		cp = searched;
542		while ((cp = strchr(cp, firstchar))) {
543			if (!strncmp(cp, searchfor, len2))
544				return 1;
545			cp++;
546		}
547	}
548	return 0;
549}
550
551int vkdb_printf(enum kdb_msgsrc src, const char *fmt, va_list ap)
552{
553	int diag;
554	int linecount;
555	int colcount;
556	int logging, saved_loglevel = 0;
557	int saved_trap_printk;
558	int got_printf_lock = 0;
559	int retlen = 0;
560	int fnd, len;
 
561	char *cp, *cp2, *cphold = NULL, replaced_byte = ' ';
562	char *moreprompt = "more> ";
563	struct console *c = console_drivers;
564	static DEFINE_SPINLOCK(kdb_printf_lock);
565	unsigned long uninitialized_var(flags);
566
567	preempt_disable();
568	saved_trap_printk = kdb_trap_printk;
569	kdb_trap_printk = 0;
570
571	/* Serialize kdb_printf if multiple cpus try to write at once.
572	 * But if any cpu goes recursive in kdb, just print the output,
573	 * even if it is interleaved with any other text.
574	 */
575	if (!KDB_STATE(PRINTF_LOCK)) {
576		KDB_STATE_SET(PRINTF_LOCK);
577		spin_lock_irqsave(&kdb_printf_lock, flags);
578		got_printf_lock = 1;
579		atomic_inc(&kdb_event);
580	} else {
581		__acquire(kdb_printf_lock);
 
582	}
583
584	diag = kdbgetintenv("LINES", &linecount);
585	if (diag || linecount <= 1)
586		linecount = 24;
587
588	diag = kdbgetintenv("COLUMNS", &colcount);
589	if (diag || colcount <= 1)
590		colcount = 80;
591
592	diag = kdbgetintenv("LOGGING", &logging);
593	if (diag)
594		logging = 0;
595
596	if (!kdb_grepping_flag || suspend_grep) {
597		/* normally, every vsnprintf starts a new buffer */
598		next_avail = kdb_buffer;
599		size_avail = sizeof(kdb_buffer);
600	}
601	vsnprintf(next_avail, size_avail, fmt, ap);
602
603	/*
604	 * If kdb_parse() found that the command was cmd xxx | grep yyy
605	 * then kdb_grepping_flag is set, and kdb_grep_string contains yyy
606	 *
607	 * Accumulate the print data up to a newline before searching it.
608	 * (vsnprintf does null-terminate the string that it generates)
609	 */
610
611	/* skip the search if prints are temporarily unconditional */
612	if (!suspend_grep && kdb_grepping_flag) {
613		cp = strchr(kdb_buffer, '\n');
614		if (!cp) {
615			/*
616			 * Special cases that don't end with newlines
617			 * but should be written without one:
618			 *   The "[nn]kdb> " prompt should
619			 *   appear at the front of the buffer.
620			 *
621			 *   The "[nn]more " prompt should also be
622			 *     (MOREPROMPT -> moreprompt)
623			 *   written *   but we print that ourselves,
624			 *   we set the suspend_grep flag to make
625			 *   it unconditional.
626			 *
627			 */
628			if (next_avail == kdb_buffer) {
629				/*
630				 * these should occur after a newline,
631				 * so they will be at the front of the
632				 * buffer
633				 */
634				cp2 = kdb_buffer;
635				len = strlen(kdb_prompt_str);
636				if (!strncmp(cp2, kdb_prompt_str, len)) {
637					/*
638					 * We're about to start a new
639					 * command, so we can go back
640					 * to normal mode.
641					 */
642					kdb_grepping_flag = 0;
643					goto kdb_printit;
644				}
645			}
646			/* no newline; don't search/write the buffer
647			   until one is there */
648			len = strlen(kdb_buffer);
649			next_avail = kdb_buffer + len;
650			size_avail = sizeof(kdb_buffer) - len;
651			goto kdb_print_out;
652		}
653
654		/*
655		 * The newline is present; print through it or discard
656		 * it, depending on the results of the search.
657		 */
658		cp++;	 	     /* to byte after the newline */
659		replaced_byte = *cp; /* remember what/where it was */
660		cphold = cp;
661		*cp = '\0';	     /* end the string for our search */
662
663		/*
664		 * We now have a newline at the end of the string
665		 * Only continue with this output if it contains the
666		 * search string.
667		 */
668		fnd = kdb_search_string(kdb_buffer, kdb_grep_string);
669		if (!fnd) {
670			/*
671			 * At this point the complete line at the start
672			 * of kdb_buffer can be discarded, as it does
673			 * not contain what the user is looking for.
674			 * Shift the buffer left.
675			 */
676			*cphold = replaced_byte;
677			strcpy(kdb_buffer, cphold);
678			len = strlen(kdb_buffer);
679			next_avail = kdb_buffer + len;
680			size_avail = sizeof(kdb_buffer) - len;
681			goto kdb_print_out;
682		}
683		if (kdb_grepping_flag >= KDB_GREPPING_FLAG_SEARCH)
684			/*
685			 * This was a interactive search (using '/' at more
686			 * prompt) and it has completed. Clear the flag.
687			 */
688			kdb_grepping_flag = 0;
689		/*
690		 * at this point the string is a full line and
691		 * should be printed, up to the null.
692		 */
693	}
694kdb_printit:
695
696	/*
697	 * Write to all consoles.
698	 */
699	retlen = strlen(kdb_buffer);
700	cp = (char *) printk_skip_level(kdb_buffer);
701	if (!dbg_kdb_mode && kgdb_connected) {
702		gdbstub_msg_write(cp, retlen - (cp - kdb_buffer));
703	} else {
704		if (dbg_io_ops && !dbg_io_ops->is_console) {
705			len = retlen - (cp - kdb_buffer);
706			cp2 = cp;
707			while (len--) {
708				dbg_io_ops->write_char(*cp2);
709				cp2++;
710			}
711		}
712		while (c) {
713			c->write(c, cp, retlen - (cp - kdb_buffer));
714			touch_nmi_watchdog();
715			c = c->next;
716		}
717	}
718	if (logging) {
719		saved_loglevel = console_loglevel;
720		console_loglevel = CONSOLE_LOGLEVEL_SILENT;
721		if (printk_get_level(kdb_buffer) || src == KDB_MSGSRC_PRINTK)
722			printk("%s", kdb_buffer);
723		else
724			pr_info("%s", kdb_buffer);
725	}
726
727	if (KDB_STATE(PAGER)) {
728		/*
729		 * Check printed string to decide how to bump the
730		 * kdb_nextline to control when the more prompt should
731		 * show up.
732		 */
733		int got = 0;
734		len = retlen;
735		while (len--) {
736			if (kdb_buffer[len] == '\n') {
737				kdb_nextline++;
738				got = 0;
739			} else if (kdb_buffer[len] == '\r') {
740				got = 0;
741			} else {
742				got++;
743			}
744		}
745		kdb_nextline += got / (colcount + 1);
746	}
747
748	/* check for having reached the LINES number of printed lines */
749	if (kdb_nextline >= linecount) {
750		char buf1[16] = "";
751
752		/* Watch out for recursion here.  Any routine that calls
753		 * kdb_printf will come back through here.  And kdb_read
754		 * uses kdb_printf to echo on serial consoles ...
755		 */
756		kdb_nextline = 1;	/* In case of recursion */
757
758		/*
759		 * Pause until cr.
760		 */
761		moreprompt = kdbgetenv("MOREPROMPT");
762		if (moreprompt == NULL)
763			moreprompt = "more> ";
764
765		kdb_input_flush();
766		c = console_drivers;
767
768		if (dbg_io_ops && !dbg_io_ops->is_console) {
769			len = strlen(moreprompt);
770			cp = moreprompt;
771			while (len--) {
772				dbg_io_ops->write_char(*cp);
773				cp++;
774			}
775		}
776		while (c) {
777			c->write(c, moreprompt, strlen(moreprompt));
778			touch_nmi_watchdog();
779			c = c->next;
780		}
781
782		if (logging)
783			printk("%s", moreprompt);
784
785		kdb_read(buf1, 2); /* '2' indicates to return
786				    * immediately after getting one key. */
787		kdb_nextline = 1;	/* Really set output line 1 */
788
789		/* empty and reset the buffer: */
790		kdb_buffer[0] = '\0';
791		next_avail = kdb_buffer;
792		size_avail = sizeof(kdb_buffer);
793		if ((buf1[0] == 'q') || (buf1[0] == 'Q')) {
794			/* user hit q or Q */
795			KDB_FLAG_SET(CMD_INTERRUPT); /* command interrupted */
796			KDB_STATE_CLEAR(PAGER);
797			/* end of command output; back to normal mode */
798			kdb_grepping_flag = 0;
799			kdb_printf("\n");
800		} else if (buf1[0] == ' ') {
801			kdb_printf("\r");
802			suspend_grep = 1; /* for this recursion */
803		} else if (buf1[0] == '\n') {
804			kdb_nextline = linecount - 1;
805			kdb_printf("\r");
806			suspend_grep = 1; /* for this recursion */
807		} else if (buf1[0] == '/' && !kdb_grepping_flag) {
808			kdb_printf("\r");
809			kdb_getstr(kdb_grep_string, KDB_GREP_STRLEN,
810				   kdbgetenv("SEARCHPROMPT") ?: "search> ");
811			*strchrnul(kdb_grep_string, '\n') = '\0';
812			kdb_grepping_flag += KDB_GREPPING_FLAG_SEARCH;
813			suspend_grep = 1; /* for this recursion */
814		} else if (buf1[0] && buf1[0] != '\n') {
815			/* user hit something other than enter */
816			suspend_grep = 1; /* for this recursion */
817			if (buf1[0] != '/')
818				kdb_printf(
819				    "\nOnly 'q', 'Q' or '/' are processed at "
820				    "more prompt, input ignored\n");
821			else
822				kdb_printf("\n'/' cannot be used during | "
823					   "grep filtering, input ignored\n");
824		} else if (kdb_grepping_flag) {
825			/* user hit enter */
826			suspend_grep = 1; /* for this recursion */
827			kdb_printf("\n");
828		}
829		kdb_input_flush();
830	}
831
832	/*
833	 * For grep searches, shift the printed string left.
834	 *  replaced_byte contains the character that was overwritten with
835	 *  the terminating null, and cphold points to the null.
836	 * Then adjust the notion of available space in the buffer.
837	 */
838	if (kdb_grepping_flag && !suspend_grep) {
839		*cphold = replaced_byte;
840		strcpy(kdb_buffer, cphold);
841		len = strlen(kdb_buffer);
842		next_avail = kdb_buffer + len;
843		size_avail = sizeof(kdb_buffer) - len;
844	}
845
846kdb_print_out:
847	suspend_grep = 0; /* end of what may have been a recursive call */
848	if (logging)
849		console_loglevel = saved_loglevel;
850	if (KDB_STATE(PRINTF_LOCK) && got_printf_lock) {
851		got_printf_lock = 0;
852		spin_unlock_irqrestore(&kdb_printf_lock, flags);
853		KDB_STATE_CLEAR(PRINTF_LOCK);
854		atomic_dec(&kdb_event);
855	} else {
856		__release(kdb_printf_lock);
857	}
858	kdb_trap_printk = saved_trap_printk;
859	preempt_enable();
860	return retlen;
861}
862
863int kdb_printf(const char *fmt, ...)
864{
865	va_list ap;
866	int r;
867
868	va_start(ap, fmt);
869	r = vkdb_printf(KDB_MSGSRC_INTERNAL, fmt, ap);
870	va_end(ap);
871
872	return r;
873}
874EXPORT_SYMBOL_GPL(kdb_printf);