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/types.h>
 13#include <linux/ctype.h>
 14#include <linux/kernel.h>
 15#include <linux/init.h>
 16#include <linux/kdev_t.h>
 17#include <linux/console.h>
 18#include <linux/string.h>
 19#include <linux/sched.h>
 20#include <linux/smp.h>
 21#include <linux/nmi.h>
 22#include <linux/delay.h>
 23#include <linux/kgdb.h>
 24#include <linux/kdb.h>
 25#include <linux/kallsyms.h>
 26#include "kdb_private.h"
 27
 28#define CMD_BUFLEN 256
 29char kdb_prompt_str[CMD_BUFLEN];
 30
 31int kdb_trap_printk;
 32int kdb_printf_cpu = -1;
 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
 51/**
 52 * kdb_handle_escape() - validity check on an accumulated escape sequence.
 53 * @buf:	Accumulated escape characters to be examined. Note that buf
 54 *		is not a string, it is an array of characters and need not be
 55 *		nil terminated.
 56 * @sz:		Number of accumulated escape characters.
 57 *
 58 * Return: -1 if the escape sequence is unwanted, 0 if it is incomplete,
 59 * otherwise it returns a mapped key value to pass to the upper layers.
 60 */
 61static int kdb_handle_escape(char *buf, size_t sz)
 62{
 63	char *lastkey = buf + sz - 1;
 64
 65	switch (sz) {
 66	case 1:
 67		if (*lastkey == '\e')
 68			return 0;
 69		break;
 70
 71	case 2: /* \e<something> */
 72		if (*lastkey == '[')
 73			return 0;
 74		break;
 75
 76	case 3:
 77		switch (*lastkey) {
 78		case 'A': /* \e[A, up arrow */
 79			return 16;
 80		case 'B': /* \e[B, down arrow */
 81			return 14;
 82		case 'C': /* \e[C, right arrow */
 83			return 6;
 84		case 'D': /* \e[D, left arrow */
 85			return 2;
 86		case '1': /* \e[<1,3,4>], may be home, del, end */
 87		case '3':
 88		case '4':
 89			return 0;
 90		}
 91		break;
 92
 93	case 4:
 94		if (*lastkey == '~') {
 95			switch (buf[2]) {
 96			case '1': /* \e[1~, home */
 97				return 1;
 98			case '3': /* \e[3~, del */
 99				return 4;
100			case '4': /* \e[4~, end */
101				return 5;
102			}
103		}
104		break;
105	}
106
107	return -1;
108}
109
110/**
111 * kdb_getchar() - Read a single character from a kdb console (or consoles).
112 *
113 * Other than polling the various consoles that are currently enabled,
114 * most of the work done in this function is dealing with escape sequences.
115 *
116 * An escape key could be the start of a vt100 control sequence such as \e[D
117 * (left arrow) or it could be a character in its own right.  The standard
118 * method for detecting the difference is to wait for 2 seconds to see if there
119 * are any other characters.  kdb is complicated by the lack of a timer service
120 * (interrupts are off), by multiple input sources. Escape sequence processing
121 * has to be done as states in the polling loop.
122 *
123 * Return: The key pressed or a control code derived from an escape sequence.
124 */
125char kdb_getchar(void)
126{
127#define ESCAPE_UDELAY 1000
128#define ESCAPE_DELAY (2*1000000/ESCAPE_UDELAY) /* 2 seconds worth of udelays */
129	char buf[4];	/* longest vt100 escape sequence is 4 bytes */
130	char *pbuf = buf;
131	int escape_delay = 0;
132	get_char_func *f, *f_prev = NULL;
133	int key;
 
134
135	for (f = &kdb_poll_funcs[0]; ; ++f) {
136		if (*f == NULL) {
137			/* Reset NMI watchdog once per poll loop */
138			touch_nmi_watchdog();
139			f = &kdb_poll_funcs[0];
140		}
141
142		key = (*f)();
143		if (key == -1) {
144			if (escape_delay) {
145				udelay(ESCAPE_UDELAY);
146				if (--escape_delay == 0)
147					return '\e';
148			}
149			continue;
150		}
151
152		/*
 
 
 
 
 
 
 
 
 
 
 
 
153		 * When the first character is received (or we get a change
154		 * input source) we set ourselves up to handle an escape
155		 * sequences (just in case).
156		 */
157		if (f_prev != f) {
158			f_prev = f;
159			pbuf = buf;
160			escape_delay = ESCAPE_DELAY;
161		}
162
163		*pbuf++ = key;
164		key = kdb_handle_escape(buf, pbuf - buf);
165		if (key < 0) /* no escape sequence; return best character */
166			return buf[pbuf - buf == 2 ? 1 : 0];
167		if (key > 0)
168			return key;
169	}
170
171	unreachable();
172}
173
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
174/*
175 * kdb_read
176 *
177 *	This function reads a string of characters, terminated by
178 *	a newline, or by reaching the end of the supplied buffer,
179 *	from the current kernel debugger console device.
180 * Parameters:
181 *	buffer	- Address of character buffer to receive input characters.
182 *	bufsize - size, in bytes, of the character buffer
183 * Returns:
184 *	Returns a pointer to the buffer containing the received
185 *	character string.  This string will be terminated by a
186 *	newline character.
187 * Locking:
188 *	No locks are required to be held upon entry to this
189 *	function.  It is not reentrant - it relies on the fact
190 *	that while kdb is running on only one "master debug" cpu.
191 * Remarks:
192 *	The buffer size must be >= 2.
193 */
194
195static char *kdb_read(char *buffer, size_t bufsize)
196{
197	char *cp = buffer;
198	char *bufend = buffer+bufsize-2;	/* Reserve space for newline
199						 * and null byte */
200	char *lastchar;
201	char *p_tmp;
202	char tmp;
203	static char tmpbuffer[CMD_BUFLEN];
204	int len = strlen(buffer);
205	int len_tmp;
206	int tab = 0;
207	int count;
208	int i;
209	int diag, dtab_count;
210	int key, buf_size, ret;
211
212
213	diag = kdbgetintenv("DTABCOUNT", &dtab_count);
214	if (diag)
215		dtab_count = 30;
216
217	if (len > 0) {
218		cp += len;
219		if (*(buffer+len-1) == '\n')
220			cp--;
221	}
222
223	lastchar = cp;
224	*cp = '\0';
225	kdb_printf("%s", buffer);
226poll_again:
227	key = kdb_getchar();
228	if (key != 9)
229		tab = 0;
230	switch (key) {
231	case 8: /* backspace */
232		if (cp > buffer) {
233			if (cp < lastchar) {
234				memcpy(tmpbuffer, cp, lastchar - cp);
235				memcpy(cp-1, tmpbuffer, lastchar - cp);
236			}
237			*(--lastchar) = '\0';
238			--cp;
239			kdb_printf("\b%s \r", cp);
240			tmp = *cp;
241			*cp = '\0';
242			kdb_printf(kdb_prompt_str);
243			kdb_printf("%s", buffer);
244			*cp = tmp;
245		}
246		break;
247	case 13: /* enter */
 
248		*lastchar++ = '\n';
249		*lastchar++ = '\0';
250		if (!KDB_STATE(KGDB_TRANS)) {
251			KDB_STATE_SET(KGDB_TRANS);
252			kdb_printf("%s", buffer);
253		}
254		kdb_printf("\n");
255		return buffer;
256	case 4: /* Del */
257		if (cp < lastchar) {
258			memcpy(tmpbuffer, cp+1, lastchar - cp - 1);
259			memcpy(cp, tmpbuffer, lastchar - cp - 1);
260			*(--lastchar) = '\0';
261			kdb_printf("%s \r", cp);
262			tmp = *cp;
263			*cp = '\0';
264			kdb_printf(kdb_prompt_str);
265			kdb_printf("%s", buffer);
266			*cp = tmp;
267		}
268		break;
269	case 1: /* Home */
270		if (cp > buffer) {
271			kdb_printf("\r");
272			kdb_printf(kdb_prompt_str);
273			cp = buffer;
 
274		}
275		break;
276	case 5: /* End */
277		if (cp < lastchar) {
278			kdb_printf("%s", cp);
279			cp = lastchar;
280		}
281		break;
282	case 2: /* Left */
283		if (cp > buffer) {
284			kdb_printf("\b");
285			--cp;
286		}
287		break;
288	case 14: /* Down */
289		memset(tmpbuffer, ' ',
290		       strlen(kdb_prompt_str) + (lastchar-buffer));
291		*(tmpbuffer+strlen(kdb_prompt_str) +
292		  (lastchar-buffer)) = '\0';
293		kdb_printf("\r%s\r", tmpbuffer);
294		*lastchar = (char)key;
295		*(lastchar+1) = '\0';
296		return lastchar;
297	case 6: /* Right */
298		if (cp < lastchar) {
299			kdb_printf("%c", *cp);
300			++cp;
301		}
302		break;
303	case 16: /* Up */
304		memset(tmpbuffer, ' ',
305		       strlen(kdb_prompt_str) + (lastchar-buffer));
306		*(tmpbuffer+strlen(kdb_prompt_str) +
307		  (lastchar-buffer)) = '\0';
308		kdb_printf("\r%s\r", tmpbuffer);
309		*lastchar = (char)key;
310		*(lastchar+1) = '\0';
311		return lastchar;
312	case 9: /* Tab */
313		if (tab < 2)
314			++tab;
315		p_tmp = buffer;
316		while (*p_tmp == ' ')
317			p_tmp++;
318		if (p_tmp > cp)
319			break;
320		memcpy(tmpbuffer, p_tmp, cp-p_tmp);
321		*(tmpbuffer + (cp-p_tmp)) = '\0';
322		p_tmp = strrchr(tmpbuffer, ' ');
323		if (p_tmp)
324			++p_tmp;
325		else
326			p_tmp = tmpbuffer;
327		len = strlen(p_tmp);
328		buf_size = sizeof(tmpbuffer) - (p_tmp - tmpbuffer);
329		count = kallsyms_symbol_complete(p_tmp, buf_size);
330		if (tab == 2 && count > 0) {
331			kdb_printf("\n%d symbols are found.", count);
332			if (count > dtab_count) {
333				count = dtab_count;
334				kdb_printf(" But only first %d symbols will"
335					   " be printed.\nYou can change the"
336					   " environment variable DTABCOUNT.",
337					   count);
338			}
339			kdb_printf("\n");
340			for (i = 0; i < count; i++) {
341				ret = kallsyms_symbol_next(p_tmp, i, buf_size);
342				if (WARN_ON(!ret))
343					break;
344				if (ret != -E2BIG)
345					kdb_printf("%s ", p_tmp);
346				else
347					kdb_printf("%s... ", p_tmp);
348				*(p_tmp + len) = '\0';
349			}
350			if (i >= dtab_count)
351				kdb_printf("...");
352			kdb_printf("\n");
353			kdb_printf(kdb_prompt_str);
354			kdb_printf("%s", buffer);
 
 
355		} else if (tab != 2 && count > 0) {
356			len_tmp = strlen(p_tmp);
357			strncpy(p_tmp+len_tmp, cp, lastchar-cp+1);
358			len_tmp = strlen(p_tmp);
359			strncpy(cp, p_tmp+len, len_tmp-len + 1);
360			len = len_tmp - len;
361			kdb_printf("%s", cp);
362			cp += len;
363			lastchar += len;
 
 
 
 
 
 
 
 
364		}
365		kdb_nextline = 1; /* reset output line number */
366		break;
367	default:
368		if (key >= 32 && lastchar < bufend) {
369			if (cp < lastchar) {
370				memcpy(tmpbuffer, cp, lastchar - cp);
371				memcpy(cp+1, tmpbuffer, lastchar - cp);
372				*++lastchar = '\0';
373				*cp = key;
374				kdb_printf("%s\r", cp);
375				++cp;
376				tmp = *cp;
377				*cp = '\0';
378				kdb_printf(kdb_prompt_str);
379				kdb_printf("%s", buffer);
380				*cp = tmp;
381			} else {
382				*++lastchar = '\0';
383				*cp++ = key;
384				/* The kgdb transition check will hide
385				 * printed characters if we think that
386				 * kgdb is connecting, until the check
387				 * fails */
388				if (!KDB_STATE(KGDB_TRANS)) {
389					if (kgdb_transition_check(buffer))
390						return buffer;
391				} else {
392					kdb_printf("%c", key);
393				}
394			}
395			/* Special escape to kgdb */
396			if (lastchar - buffer >= 5 &&
397			    strcmp(lastchar - 5, "$?#3f") == 0) {
398				kdb_gdb_state_pass(lastchar - 5);
399				strcpy(buffer, "kgdb");
400				KDB_STATE_SET(DOING_KGDB);
401				return buffer;
402			}
403			if (lastchar - buffer >= 11 &&
404			    strcmp(lastchar - 11, "$qSupported") == 0) {
405				kdb_gdb_state_pass(lastchar - 11);
406				strcpy(buffer, "kgdb");
407				KDB_STATE_SET(DOING_KGDB);
408				return buffer;
409			}
410		}
411		break;
412	}
413	goto poll_again;
414}
415
416/*
417 * kdb_getstr
418 *
419 *	Print the prompt string and read a command from the
420 *	input device.
421 *
422 * Parameters:
423 *	buffer	Address of buffer to receive command
424 *	bufsize Size of buffer in bytes
425 *	prompt	Pointer to string to use as prompt string
426 * Returns:
427 *	Pointer to command buffer.
428 * Locking:
429 *	None.
430 * Remarks:
431 *	For SMP kernels, the processor number will be
432 *	substituted for %d, %x or %o in the prompt.
433 */
434
435char *kdb_getstr(char *buffer, size_t bufsize, const char *prompt)
436{
437	if (prompt && kdb_prompt_str != prompt)
438		strscpy(kdb_prompt_str, prompt, CMD_BUFLEN);
439	kdb_printf(kdb_prompt_str);
440	kdb_nextline = 1;	/* Prompt and input resets line number */
441	return kdb_read(buffer, bufsize);
442}
443
444/*
445 * kdb_input_flush
446 *
447 *	Get rid of any buffered console input.
448 *
449 * Parameters:
450 *	none
451 * Returns:
452 *	nothing
453 * Locking:
454 *	none
455 * Remarks:
456 *	Call this function whenever you want to flush input.  If there is any
457 *	outstanding input, it ignores all characters until there has been no
458 *	data for approximately 1ms.
459 */
460
461static void kdb_input_flush(void)
462{
463	get_char_func *f;
464	int res;
465	int flush_delay = 1;
466	while (flush_delay) {
467		flush_delay--;
468empty:
469		touch_nmi_watchdog();
470		for (f = &kdb_poll_funcs[0]; *f; ++f) {
471			res = (*f)();
472			if (res != -1) {
473				flush_delay = 1;
474				goto empty;
475			}
476		}
477		if (flush_delay)
478			mdelay(1);
479	}
480}
481
482/*
483 * kdb_printf
484 *
485 *	Print a string to the output device(s).
486 *
487 * Parameters:
488 *	printf-like format and optional args.
489 * Returns:
490 *	0
491 * Locking:
492 *	None.
493 * Remarks:
494 *	use 'kdbcons->write()' to avoid polluting 'log_buf' with
495 *	kdb output.
496 *
497 *  If the user is doing a cmd args | grep srch
498 *  then kdb_grepping_flag is set.
499 *  In that case we need to accumulate full lines (ending in \n) before
500 *  searching for the pattern.
501 */
502
503static char kdb_buffer[256];	/* A bit too big to go on stack */
504static char *next_avail = kdb_buffer;
505static int  size_avail;
506static int  suspend_grep;
507
508/*
509 * search arg1 to see if it contains arg2
510 * (kdmain.c provides flags for ^pat and pat$)
511 *
512 * return 1 for found, 0 for not found
513 */
514static int kdb_search_string(char *searched, char *searchfor)
515{
516	char firstchar, *cp;
517	int len1, len2;
518
519	/* not counting the newline at the end of "searched" */
520	len1 = strlen(searched)-1;
521	len2 = strlen(searchfor);
522	if (len1 < len2)
523		return 0;
524	if (kdb_grep_leading && kdb_grep_trailing && len1 != len2)
525		return 0;
526	if (kdb_grep_leading) {
527		if (!strncmp(searched, searchfor, len2))
528			return 1;
529	} else if (kdb_grep_trailing) {
530		if (!strncmp(searched+len1-len2, searchfor, len2))
531			return 1;
532	} else {
533		firstchar = *searchfor;
534		cp = searched;
535		while ((cp = strchr(cp, firstchar))) {
536			if (!strncmp(cp, searchfor, len2))
537				return 1;
538			cp++;
539		}
540	}
541	return 0;
542}
543
544static void kdb_msg_write(const char *msg, int msg_len)
545{
546	struct console *c;
547	const char *cp;
548	int cookie;
549	int len;
550
551	if (msg_len == 0)
552		return;
553
554	cp = msg;
555	len = msg_len;
556
557	while (len--) {
558		dbg_io_ops->write_char(*cp);
559		cp++;
560	}
561
562	/*
563	 * The console_srcu_read_lock() only provides safe console list
564	 * traversal. The use of the ->write() callback relies on all other
565	 * CPUs being stopped at the moment and console drivers being able to
566	 * handle reentrance when @oops_in_progress is set.
567	 *
568	 * There is no guarantee that every console driver can handle
569	 * reentrance in this way; the developer deploying the debugger
570	 * is responsible for ensuring that the console drivers they
571	 * have selected handle reentrance appropriately.
572	 */
573	cookie = console_srcu_read_lock();
574	for_each_console_srcu(c) {
575		if (!(console_srcu_read_flags(c) & CON_ENABLED))
576			continue;
577		if (c == dbg_io_ops->cons)
 
 
578			continue;
579		/*
580		 * Set oops_in_progress to encourage the console drivers to
581		 * disregard their internal spin locks: in the current calling
582		 * context the risk of deadlock is a bigger problem than risks
583		 * due to re-entering the console driver. We operate directly on
584		 * oops_in_progress rather than using bust_spinlocks() because
585		 * the calls bust_spinlocks() makes on exit are not appropriate
586		 * for this calling context.
587		 */
588		++oops_in_progress;
589		c->write(c, msg, msg_len);
590		--oops_in_progress;
591		touch_nmi_watchdog();
592	}
593	console_srcu_read_unlock(cookie);
594}
595
596int vkdb_printf(enum kdb_msgsrc src, const char *fmt, va_list ap)
597{
598	int diag;
599	int linecount;
600	int colcount;
601	int logging, saved_loglevel = 0;
602	int retlen = 0;
603	int fnd, len;
604	int this_cpu, old_cpu;
605	char *cp, *cp2, *cphold = NULL, replaced_byte = ' ';
606	char *moreprompt = "more> ";
607	unsigned long flags;
608
609	/* Serialize kdb_printf if multiple cpus try to write at once.
610	 * But if any cpu goes recursive in kdb, just print the output,
611	 * even if it is interleaved with any other text.
612	 */
613	local_irq_save(flags);
614	this_cpu = smp_processor_id();
615	for (;;) {
616		old_cpu = cmpxchg(&kdb_printf_cpu, -1, this_cpu);
617		if (old_cpu == -1 || old_cpu == this_cpu)
618			break;
619
620		cpu_relax();
621	}
622
623	diag = kdbgetintenv("LINES", &linecount);
624	if (diag || linecount <= 1)
625		linecount = 24;
626
627	diag = kdbgetintenv("COLUMNS", &colcount);
628	if (diag || colcount <= 1)
629		colcount = 80;
630
631	diag = kdbgetintenv("LOGGING", &logging);
632	if (diag)
633		logging = 0;
634
635	if (!kdb_grepping_flag || suspend_grep) {
636		/* normally, every vsnprintf starts a new buffer */
637		next_avail = kdb_buffer;
638		size_avail = sizeof(kdb_buffer);
639	}
640	vsnprintf(next_avail, size_avail, fmt, ap);
641
642	/*
643	 * If kdb_parse() found that the command was cmd xxx | grep yyy
644	 * then kdb_grepping_flag is set, and kdb_grep_string contains yyy
645	 *
646	 * Accumulate the print data up to a newline before searching it.
647	 * (vsnprintf does null-terminate the string that it generates)
648	 */
649
650	/* skip the search if prints are temporarily unconditional */
651	if (!suspend_grep && kdb_grepping_flag) {
652		cp = strchr(kdb_buffer, '\n');
653		if (!cp) {
654			/*
655			 * Special cases that don't end with newlines
656			 * but should be written without one:
657			 *   The "[nn]kdb> " prompt should
658			 *   appear at the front of the buffer.
659			 *
660			 *   The "[nn]more " prompt should also be
661			 *     (MOREPROMPT -> moreprompt)
662			 *   written *   but we print that ourselves,
663			 *   we set the suspend_grep flag to make
664			 *   it unconditional.
665			 *
666			 */
667			if (next_avail == kdb_buffer) {
668				/*
669				 * these should occur after a newline,
670				 * so they will be at the front of the
671				 * buffer
672				 */
673				cp2 = kdb_buffer;
674				len = strlen(kdb_prompt_str);
675				if (!strncmp(cp2, kdb_prompt_str, len)) {
676					/*
677					 * We're about to start a new
678					 * command, so we can go back
679					 * to normal mode.
680					 */
681					kdb_grepping_flag = 0;
682					goto kdb_printit;
683				}
684			}
685			/* no newline; don't search/write the buffer
686			   until one is there */
687			len = strlen(kdb_buffer);
688			next_avail = kdb_buffer + len;
689			size_avail = sizeof(kdb_buffer) - len;
690			goto kdb_print_out;
691		}
692
693		/*
694		 * The newline is present; print through it or discard
695		 * it, depending on the results of the search.
696		 */
697		cp++;	 	     /* to byte after the newline */
698		replaced_byte = *cp; /* remember what/where it was */
699		cphold = cp;
700		*cp = '\0';	     /* end the string for our search */
701
702		/*
703		 * We now have a newline at the end of the string
704		 * Only continue with this output if it contains the
705		 * search string.
706		 */
707		fnd = kdb_search_string(kdb_buffer, kdb_grep_string);
708		if (!fnd) {
709			/*
710			 * At this point the complete line at the start
711			 * of kdb_buffer can be discarded, as it does
712			 * not contain what the user is looking for.
713			 * Shift the buffer left.
714			 */
715			*cphold = replaced_byte;
716			strcpy(kdb_buffer, cphold);
717			len = strlen(kdb_buffer);
718			next_avail = kdb_buffer + len;
719			size_avail = sizeof(kdb_buffer) - len;
720			goto kdb_print_out;
721		}
722		if (kdb_grepping_flag >= KDB_GREPPING_FLAG_SEARCH) {
723			/*
724			 * This was a interactive search (using '/' at more
725			 * prompt) and it has completed. Replace the \0 with
726			 * its original value to ensure multi-line strings
727			 * are handled properly, and return to normal mode.
728			 */
729			*cphold = replaced_byte;
730			kdb_grepping_flag = 0;
731		}
732		/*
733		 * at this point the string is a full line and
734		 * should be printed, up to the null.
735		 */
736	}
737kdb_printit:
738
739	/*
740	 * Write to all consoles.
741	 */
742	retlen = strlen(kdb_buffer);
743	cp = (char *) printk_skip_headers(kdb_buffer);
744	if (!dbg_kdb_mode && kgdb_connected)
745		gdbstub_msg_write(cp, retlen - (cp - kdb_buffer));
746	else
747		kdb_msg_write(cp, retlen - (cp - kdb_buffer));
748
749	if (logging) {
750		saved_loglevel = console_loglevel;
751		console_loglevel = CONSOLE_LOGLEVEL_SILENT;
752		if (printk_get_level(kdb_buffer) || src == KDB_MSGSRC_PRINTK)
753			printk("%s", kdb_buffer);
754		else
755			pr_info("%s", kdb_buffer);
756	}
757
758	if (KDB_STATE(PAGER)) {
759		/*
760		 * Check printed string to decide how to bump the
761		 * kdb_nextline to control when the more prompt should
762		 * show up.
763		 */
764		int got = 0;
765		len = retlen;
766		while (len--) {
767			if (kdb_buffer[len] == '\n') {
768				kdb_nextline++;
769				got = 0;
770			} else if (kdb_buffer[len] == '\r') {
771				got = 0;
772			} else {
773				got++;
774			}
775		}
776		kdb_nextline += got / (colcount + 1);
777	}
778
779	/* check for having reached the LINES number of printed lines */
780	if (kdb_nextline >= linecount) {
781		char ch;
782
783		/* Watch out for recursion here.  Any routine that calls
784		 * kdb_printf will come back through here.  And kdb_read
785		 * uses kdb_printf to echo on serial consoles ...
786		 */
787		kdb_nextline = 1;	/* In case of recursion */
788
789		/*
790		 * Pause until cr.
791		 */
792		moreprompt = kdbgetenv("MOREPROMPT");
793		if (moreprompt == NULL)
794			moreprompt = "more> ";
795
796		kdb_input_flush();
797		kdb_msg_write(moreprompt, strlen(moreprompt));
798
799		if (logging)
800			printk("%s", moreprompt);
801
802		ch = kdb_getchar();
803		kdb_nextline = 1;	/* Really set output line 1 */
804
805		/* empty and reset the buffer: */
806		kdb_buffer[0] = '\0';
807		next_avail = kdb_buffer;
808		size_avail = sizeof(kdb_buffer);
809		if ((ch == 'q') || (ch == 'Q')) {
810			/* user hit q or Q */
811			KDB_FLAG_SET(CMD_INTERRUPT); /* command interrupted */
812			KDB_STATE_CLEAR(PAGER);
813			/* end of command output; back to normal mode */
814			kdb_grepping_flag = 0;
815			kdb_printf("\n");
816		} else if (ch == ' ') {
817			kdb_printf("\r");
818			suspend_grep = 1; /* for this recursion */
819		} else if (ch == '\n' || ch == '\r') {
820			kdb_nextline = linecount - 1;
821			kdb_printf("\r");
822			suspend_grep = 1; /* for this recursion */
823		} else if (ch == '/' && !kdb_grepping_flag) {
824			kdb_printf("\r");
825			kdb_getstr(kdb_grep_string, KDB_GREP_STRLEN,
826				   kdbgetenv("SEARCHPROMPT") ?: "search> ");
827			*strchrnul(kdb_grep_string, '\n') = '\0';
828			kdb_grepping_flag += KDB_GREPPING_FLAG_SEARCH;
829			suspend_grep = 1; /* for this recursion */
830		} else if (ch) {
831			/* user hit something unexpected */
832			suspend_grep = 1; /* for this recursion */
833			if (ch != '/')
834				kdb_printf(
835				    "\nOnly 'q', 'Q' or '/' are processed at "
836				    "more prompt, input ignored\n");
837			else
838				kdb_printf("\n'/' cannot be used during | "
839					   "grep filtering, input ignored\n");
840		} else if (kdb_grepping_flag) {
841			/* user hit enter */
842			suspend_grep = 1; /* for this recursion */
843			kdb_printf("\n");
844		}
845		kdb_input_flush();
846	}
847
848	/*
849	 * For grep searches, shift the printed string left.
850	 *  replaced_byte contains the character that was overwritten with
851	 *  the terminating null, and cphold points to the null.
852	 * Then adjust the notion of available space in the buffer.
853	 */
854	if (kdb_grepping_flag && !suspend_grep) {
855		*cphold = replaced_byte;
856		strcpy(kdb_buffer, cphold);
857		len = strlen(kdb_buffer);
858		next_avail = kdb_buffer + len;
859		size_avail = sizeof(kdb_buffer) - len;
860	}
861
862kdb_print_out:
863	suspend_grep = 0; /* end of what may have been a recursive call */
864	if (logging)
865		console_loglevel = saved_loglevel;
866	/* kdb_printf_cpu locked the code above. */
867	smp_store_release(&kdb_printf_cpu, old_cpu);
868	local_irq_restore(flags);
869	return retlen;
870}
871
872int kdb_printf(const char *fmt, ...)
873{
874	va_list ap;
875	int r;
876
877	va_start(ap, fmt);
878	r = vkdb_printf(KDB_MSGSRC_INTERNAL, fmt, ap);
879	va_end(ap);
880
881	return r;
882}
883EXPORT_SYMBOL_GPL(kdb_printf);