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;
 33int kdb_printf_cpu = -1;
 34
 35static 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
 52static 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
204static 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, buf_size, ret;
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);
235poll_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		buf_size = sizeof(tmpbuffer) - (p_tmp - tmpbuffer);
340		count = kallsyms_symbol_complete(p_tmp, buf_size);
 
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				ret = kallsyms_symbol_next(p_tmp, i, buf_size);
353				if (WARN_ON(!ret))
354					break;
355				if (ret != -E2BIG)
356					kdb_printf("%s ", p_tmp);
357				else
358					kdb_printf("%s... ", p_tmp);
359				*(p_tmp + len) = '\0';
360			}
361			if (i >= dtab_count)
362				kdb_printf("...");
363			kdb_printf("\n");
364			kdb_printf(kdb_prompt_str);
365			kdb_printf("%s", buffer);
366		} else if (tab != 2 && count > 0) {
367			len_tmp = strlen(p_tmp);
368			strncpy(p_tmp+len_tmp, cp, lastchar-cp+1);
369			len_tmp = strlen(p_tmp);
370			strncpy(cp, p_tmp+len, len_tmp-len + 1);
371			len = len_tmp - len;
372			kdb_printf("%s", cp);
373			cp += len;
374			lastchar += len;
375		}
376		kdb_nextline = 1; /* reset output line number */
377		break;
378	default:
379		if (key >= 32 && lastchar < bufend) {
380			if (cp < lastchar) {
381				memcpy(tmpbuffer, cp, lastchar - cp);
382				memcpy(cp+1, tmpbuffer, lastchar - cp);
383				*++lastchar = '\0';
384				*cp = key;
385				kdb_printf("%s\r", cp);
386				++cp;
387				tmp = *cp;
388				*cp = '\0';
389				kdb_printf(kdb_prompt_str);
390				kdb_printf("%s", buffer);
391				*cp = tmp;
392			} else {
393				*++lastchar = '\0';
394				*cp++ = key;
395				/* The kgdb transition check will hide
396				 * printed characters if we think that
397				 * kgdb is connecting, until the check
398				 * fails */
399				if (!KDB_STATE(KGDB_TRANS)) {
400					if (kgdb_transition_check(buffer))
401						return buffer;
402				} else {
403					kdb_printf("%c", key);
404				}
405			}
406			/* Special escape to kgdb */
407			if (lastchar - buffer >= 5 &&
408			    strcmp(lastchar - 5, "$?#3f") == 0) {
409				kdb_gdb_state_pass(lastchar - 5);
410				strcpy(buffer, "kgdb");
411				KDB_STATE_SET(DOING_KGDB);
412				return buffer;
413			}
414			if (lastchar - buffer >= 11 &&
415			    strcmp(lastchar - 11, "$qSupported") == 0) {
416				kdb_gdb_state_pass(lastchar - 11);
417				strcpy(buffer, "kgdb");
418				KDB_STATE_SET(DOING_KGDB);
419				return buffer;
420			}
421		}
422		break;
423	}
424	goto poll_again;
425}
426
427/*
428 * kdb_getstr
429 *
430 *	Print the prompt string and read a command from the
431 *	input device.
432 *
433 * Parameters:
434 *	buffer	Address of buffer to receive command
435 *	bufsize Size of buffer in bytes
436 *	prompt	Pointer to string to use as prompt string
437 * Returns:
438 *	Pointer to command buffer.
439 * Locking:
440 *	None.
441 * Remarks:
442 *	For SMP kernels, the processor number will be
443 *	substituted for %d, %x or %o in the prompt.
444 */
445
446char *kdb_getstr(char *buffer, size_t bufsize, const char *prompt)
447{
448	if (prompt && kdb_prompt_str != prompt)
449		strscpy(kdb_prompt_str, prompt, CMD_BUFLEN);
450	kdb_printf(kdb_prompt_str);
451	kdb_nextline = 1;	/* Prompt and input resets line number */
452	return kdb_read(buffer, bufsize);
453}
454
455/*
456 * kdb_input_flush
457 *
458 *	Get rid of any buffered console input.
459 *
460 * Parameters:
461 *	none
462 * Returns:
463 *	nothing
464 * Locking:
465 *	none
466 * Remarks:
467 *	Call this function whenever you want to flush input.  If there is any
468 *	outstanding input, it ignores all characters until there has been no
469 *	data for approximately 1ms.
470 */
471
472static void kdb_input_flush(void)
473{
474	get_char_func *f;
475	int res;
476	int flush_delay = 1;
477	while (flush_delay) {
478		flush_delay--;
479empty:
480		touch_nmi_watchdog();
481		for (f = &kdb_poll_funcs[0]; *f; ++f) {
482			res = (*f)();
483			if (res != -1) {
484				flush_delay = 1;
485				goto empty;
486			}
487		}
488		if (flush_delay)
489			mdelay(1);
490	}
491}
492
493/*
494 * kdb_printf
495 *
496 *	Print a string to the output device(s).
497 *
498 * Parameters:
499 *	printf-like format and optional args.
500 * Returns:
501 *	0
502 * Locking:
503 *	None.
504 * Remarks:
505 *	use 'kdbcons->write()' to avoid polluting 'log_buf' with
506 *	kdb output.
507 *
508 *  If the user is doing a cmd args | grep srch
509 *  then kdb_grepping_flag is set.
510 *  In that case we need to accumulate full lines (ending in \n) before
511 *  searching for the pattern.
512 */
513
514static char kdb_buffer[256];	/* A bit too big to go on stack */
515static char *next_avail = kdb_buffer;
516static int  size_avail;
517static int  suspend_grep;
518
519/*
520 * search arg1 to see if it contains arg2
521 * (kdmain.c provides flags for ^pat and pat$)
522 *
523 * return 1 for found, 0 for not found
524 */
525static int kdb_search_string(char *searched, char *searchfor)
526{
527	char firstchar, *cp;
528	int len1, len2;
529
530	/* not counting the newline at the end of "searched" */
531	len1 = strlen(searched)-1;
532	len2 = strlen(searchfor);
533	if (len1 < len2)
534		return 0;
535	if (kdb_grep_leading && kdb_grep_trailing && len1 != len2)
536		return 0;
537	if (kdb_grep_leading) {
538		if (!strncmp(searched, searchfor, len2))
539			return 1;
540	} else if (kdb_grep_trailing) {
541		if (!strncmp(searched+len1-len2, searchfor, len2))
542			return 1;
543	} else {
544		firstchar = *searchfor;
545		cp = searched;
546		while ((cp = strchr(cp, firstchar))) {
547			if (!strncmp(cp, searchfor, len2))
548				return 1;
549			cp++;
550		}
551	}
552	return 0;
553}
554
555int vkdb_printf(enum kdb_msgsrc src, const char *fmt, va_list ap)
556{
557	int diag;
558	int linecount;
559	int colcount;
560	int logging, saved_loglevel = 0;
561	int retlen = 0;
562	int fnd, len;
563	int this_cpu, old_cpu;
564	char *cp, *cp2, *cphold = NULL, replaced_byte = ' ';
565	char *moreprompt = "more> ";
566	struct console *c = console_drivers;
567	unsigned long uninitialized_var(flags);
568
569	/* Serialize kdb_printf if multiple cpus try to write at once.
570	 * But if any cpu goes recursive in kdb, just print the output,
571	 * even if it is interleaved with any other text.
572	 */
573	local_irq_save(flags);
574	this_cpu = smp_processor_id();
575	for (;;) {
576		old_cpu = cmpxchg(&kdb_printf_cpu, -1, this_cpu);
577		if (old_cpu == -1 || old_cpu == this_cpu)
578			break;
579
580		cpu_relax();
581	}
582
583	diag = kdbgetintenv("LINES", &linecount);
584	if (diag || linecount <= 1)
585		linecount = 24;
586
587	diag = kdbgetintenv("COLUMNS", &colcount);
588	if (diag || colcount <= 1)
589		colcount = 80;
590
591	diag = kdbgetintenv("LOGGING", &logging);
592	if (diag)
593		logging = 0;
594
595	if (!kdb_grepping_flag || suspend_grep) {
596		/* normally, every vsnprintf starts a new buffer */
597		next_avail = kdb_buffer;
598		size_avail = sizeof(kdb_buffer);
599	}
600	vsnprintf(next_avail, size_avail, fmt, ap);
601
602	/*
603	 * If kdb_parse() found that the command was cmd xxx | grep yyy
604	 * then kdb_grepping_flag is set, and kdb_grep_string contains yyy
605	 *
606	 * Accumulate the print data up to a newline before searching it.
607	 * (vsnprintf does null-terminate the string that it generates)
608	 */
609
610	/* skip the search if prints are temporarily unconditional */
611	if (!suspend_grep && kdb_grepping_flag) {
612		cp = strchr(kdb_buffer, '\n');
613		if (!cp) {
614			/*
615			 * Special cases that don't end with newlines
616			 * but should be written without one:
617			 *   The "[nn]kdb> " prompt should
618			 *   appear at the front of the buffer.
619			 *
620			 *   The "[nn]more " prompt should also be
621			 *     (MOREPROMPT -> moreprompt)
622			 *   written *   but we print that ourselves,
623			 *   we set the suspend_grep flag to make
624			 *   it unconditional.
625			 *
626			 */
627			if (next_avail == kdb_buffer) {
628				/*
629				 * these should occur after a newline,
630				 * so they will be at the front of the
631				 * buffer
632				 */
633				cp2 = kdb_buffer;
634				len = strlen(kdb_prompt_str);
635				if (!strncmp(cp2, kdb_prompt_str, len)) {
636					/*
637					 * We're about to start a new
638					 * command, so we can go back
639					 * to normal mode.
640					 */
641					kdb_grepping_flag = 0;
642					goto kdb_printit;
643				}
644			}
645			/* no newline; don't search/write the buffer
646			   until one is there */
647			len = strlen(kdb_buffer);
648			next_avail = kdb_buffer + len;
649			size_avail = sizeof(kdb_buffer) - len;
650			goto kdb_print_out;
651		}
652
653		/*
654		 * The newline is present; print through it or discard
655		 * it, depending on the results of the search.
656		 */
657		cp++;	 	     /* to byte after the newline */
658		replaced_byte = *cp; /* remember what/where it was */
659		cphold = cp;
660		*cp = '\0';	     /* end the string for our search */
661
662		/*
663		 * We now have a newline at the end of the string
664		 * Only continue with this output if it contains the
665		 * search string.
666		 */
667		fnd = kdb_search_string(kdb_buffer, kdb_grep_string);
668		if (!fnd) {
669			/*
670			 * At this point the complete line at the start
671			 * of kdb_buffer can be discarded, as it does
672			 * not contain what the user is looking for.
673			 * Shift the buffer left.
674			 */
675			*cphold = replaced_byte;
676			strcpy(kdb_buffer, cphold);
677			len = strlen(kdb_buffer);
678			next_avail = kdb_buffer + len;
679			size_avail = sizeof(kdb_buffer) - len;
680			goto kdb_print_out;
681		}
682		if (kdb_grepping_flag >= KDB_GREPPING_FLAG_SEARCH)
683			/*
684			 * This was a interactive search (using '/' at more
685			 * prompt) and it has completed. Clear the flag.
686			 */
687			kdb_grepping_flag = 0;
688		/*
689		 * at this point the string is a full line and
690		 * should be printed, up to the null.
691		 */
692	}
693kdb_printit:
694
695	/*
696	 * Write to all consoles.
697	 */
698	retlen = strlen(kdb_buffer);
699	cp = (char *) printk_skip_headers(kdb_buffer);
700	if (!dbg_kdb_mode && kgdb_connected) {
701		gdbstub_msg_write(cp, retlen - (cp - kdb_buffer));
702	} else {
703		if (dbg_io_ops && !dbg_io_ops->is_console) {
704			len = retlen - (cp - kdb_buffer);
705			cp2 = cp;
706			while (len--) {
707				dbg_io_ops->write_char(*cp2);
708				cp2++;
709			}
710		}
711		while (c) {
712			c->write(c, cp, retlen - (cp - kdb_buffer));
713			touch_nmi_watchdog();
714			c = c->next;
715		}
716	}
717	if (logging) {
718		saved_loglevel = console_loglevel;
719		console_loglevel = CONSOLE_LOGLEVEL_SILENT;
720		if (printk_get_level(kdb_buffer) || src == KDB_MSGSRC_PRINTK)
721			printk("%s", kdb_buffer);
722		else
723			pr_info("%s", kdb_buffer);
724	}
725
726	if (KDB_STATE(PAGER)) {
727		/*
728		 * Check printed string to decide how to bump the
729		 * kdb_nextline to control when the more prompt should
730		 * show up.
731		 */
732		int got = 0;
733		len = retlen;
734		while (len--) {
735			if (kdb_buffer[len] == '\n') {
736				kdb_nextline++;
737				got = 0;
738			} else if (kdb_buffer[len] == '\r') {
739				got = 0;
740			} else {
741				got++;
742			}
743		}
744		kdb_nextline += got / (colcount + 1);
745	}
746
747	/* check for having reached the LINES number of printed lines */
748	if (kdb_nextline >= linecount) {
749		char buf1[16] = "";
750
751		/* Watch out for recursion here.  Any routine that calls
752		 * kdb_printf will come back through here.  And kdb_read
753		 * uses kdb_printf to echo on serial consoles ...
754		 */
755		kdb_nextline = 1;	/* In case of recursion */
756
757		/*
758		 * Pause until cr.
759		 */
760		moreprompt = kdbgetenv("MOREPROMPT");
761		if (moreprompt == NULL)
762			moreprompt = "more> ";
763
764		kdb_input_flush();
765		c = console_drivers;
766
767		if (dbg_io_ops && !dbg_io_ops->is_console) {
768			len = strlen(moreprompt);
769			cp = moreprompt;
770			while (len--) {
771				dbg_io_ops->write_char(*cp);
772				cp++;
773			}
774		}
775		while (c) {
776			c->write(c, moreprompt, strlen(moreprompt));
777			touch_nmi_watchdog();
778			c = c->next;
779		}
780
781		if (logging)
782			printk("%s", moreprompt);
783
784		kdb_read(buf1, 2); /* '2' indicates to return
785				    * immediately after getting one key. */
786		kdb_nextline = 1;	/* Really set output line 1 */
787
788		/* empty and reset the buffer: */
789		kdb_buffer[0] = '\0';
790		next_avail = kdb_buffer;
791		size_avail = sizeof(kdb_buffer);
792		if ((buf1[0] == 'q') || (buf1[0] == 'Q')) {
793			/* user hit q or Q */
794			KDB_FLAG_SET(CMD_INTERRUPT); /* command interrupted */
795			KDB_STATE_CLEAR(PAGER);
796			/* end of command output; back to normal mode */
797			kdb_grepping_flag = 0;
798			kdb_printf("\n");
799		} else if (buf1[0] == ' ') {
800			kdb_printf("\r");
801			suspend_grep = 1; /* for this recursion */
802		} else if (buf1[0] == '\n') {
803			kdb_nextline = linecount - 1;
804			kdb_printf("\r");
805			suspend_grep = 1; /* for this recursion */
806		} else if (buf1[0] == '/' && !kdb_grepping_flag) {
807			kdb_printf("\r");
808			kdb_getstr(kdb_grep_string, KDB_GREP_STRLEN,
809				   kdbgetenv("SEARCHPROMPT") ?: "search> ");
810			*strchrnul(kdb_grep_string, '\n') = '\0';
811			kdb_grepping_flag += KDB_GREPPING_FLAG_SEARCH;
812			suspend_grep = 1; /* for this recursion */
813		} else if (buf1[0] && buf1[0] != '\n') {
814			/* user hit something other than enter */
815			suspend_grep = 1; /* for this recursion */
816			if (buf1[0] != '/')
817				kdb_printf(
818				    "\nOnly 'q', 'Q' or '/' are processed at "
819				    "more prompt, input ignored\n");
820			else
821				kdb_printf("\n'/' cannot be used during | "
822					   "grep filtering, input ignored\n");
823		} else if (kdb_grepping_flag) {
824			/* user hit enter */
825			suspend_grep = 1; /* for this recursion */
826			kdb_printf("\n");
827		}
828		kdb_input_flush();
829	}
830
831	/*
832	 * For grep searches, shift the printed string left.
833	 *  replaced_byte contains the character that was overwritten with
834	 *  the terminating null, and cphold points to the null.
835	 * Then adjust the notion of available space in the buffer.
836	 */
837	if (kdb_grepping_flag && !suspend_grep) {
838		*cphold = replaced_byte;
839		strcpy(kdb_buffer, cphold);
840		len = strlen(kdb_buffer);
841		next_avail = kdb_buffer + len;
842		size_avail = sizeof(kdb_buffer) - len;
843	}
844
845kdb_print_out:
846	suspend_grep = 0; /* end of what may have been a recursive call */
847	if (logging)
848		console_loglevel = saved_loglevel;
849	/* kdb_printf_cpu locked the code above. */
850	smp_store_release(&kdb_printf_cpu, old_cpu);
851	local_irq_restore(flags);
852	return retlen;
853}
854
855int kdb_printf(const char *fmt, ...)
856{
857	va_list ap;
858	int r;
859
860	va_start(ap, fmt);
861	r = vkdb_printf(KDB_MSGSRC_INTERNAL, fmt, ap);
862	va_end(ap);
863
864	return r;
865}
866EXPORT_SYMBOL_GPL(kdb_printf);