Initial import

1 files changed, 874 insertions, 0 deletions

diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c
new file mode 100644
index 000000000..6697a3d87
--- /dev/null
+++ b/kernel/debug/kdb/kdb_io.c
@@ -0,0 +1,874 @@
+/*
+ * Kernel Debugger Architecture Independent Console I/O handler
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (c) 1999-2006 Silicon Graphics, Inc.  All Rights Reserved.
+ * Copyright (c) 2009 Wind River Systems, Inc.  All Rights Reserved.
+ */
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/ctype.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/kdev_t.h>
+#include <linux/console.h>
+#include <linux/string.h>
+#include <linux/sched.h>
+#include <linux/smp.h>
+#include <linux/nmi.h>
+#include <linux/delay.h>
+#include <linux/kgdb.h>
+#include <linux/kdb.h>
+#include <linux/kallsyms.h>
+#include "kdb_private.h"
+
+#define CMD_BUFLEN 256
+char kdb_prompt_str[CMD_BUFLEN];
+
+int kdb_trap_printk;
+
+static int kgdb_transition_check(char *buffer)
+{
+	if (buffer[0] != '+' && buffer[0] != '$') {
+		KDB_STATE_SET(KGDB_TRANS);
+		kdb_printf("%s", buffer);
+	} else {
+		int slen = strlen(buffer);
+		if (slen > 3 && buffer[slen - 3] == '#') {
+			kdb_gdb_state_pass(buffer);
+			strcpy(buffer, "kgdb");
+			KDB_STATE_SET(DOING_KGDB);
+			return 1;
+		}
+	}
+	return 0;
+}
+
+static int kdb_read_get_key(char *buffer, size_t bufsize)
+{
+#define ESCAPE_UDELAY 1000
+#define ESCAPE_DELAY (2*1000000/ESCAPE_UDELAY) /* 2 seconds worth of udelays */
+	char escape_data[5];	/* longest vt100 escape sequence is 4 bytes */
+	char *ped = escape_data;
+	int escape_delay = 0;
+	get_char_func *f, *f_escape = NULL;
+	int key;
+
+	for (f = &kdb_poll_funcs[0]; ; ++f) {
+		if (*f == NULL) {
+			/* Reset NMI watchdog once per poll loop */
+			touch_nmi_watchdog();
+			f = &kdb_poll_funcs[0];
+		}
+		if (escape_delay == 2) {
+			*ped = '\0';
+			ped = escape_data;
+			--escape_delay;
+		}
+		if (escape_delay == 1) {
+			key = *ped++;
+			if (!*ped)
+				--escape_delay;
+			break;
+		}
+		key = (*f)();
+		if (key == -1) {
+			if (escape_delay) {
+				udelay(ESCAPE_UDELAY);
+				--escape_delay;
+			}
+			continue;
+		}
+		if (bufsize <= 2) {
+			if (key == '\r')
+				key = '\n';
+			*buffer++ = key;
+			*buffer = '\0';
+			return -1;
+		}
+		if (escape_delay == 0 && key == '\e') {
+			escape_delay = ESCAPE_DELAY;
+			ped = escape_data;
+			f_escape = f;
+		}
+		if (escape_delay) {
+			*ped++ = key;
+			if (f_escape != f) {
+				escape_delay = 2;
+				continue;
+			}
+			if (ped - escape_data == 1) {
+				/* \e */
+				continue;
+			} else if (ped - escape_data == 2) {
+				/* \e<something> */
+				if (key != '[')
+					escape_delay = 2;
+				continue;
+			} else if (ped - escape_data == 3) {
+				/* \e[<something> */
+				int mapkey = 0;
+				switch (key) {
+				case 'A': /* \e[A, up arrow */
+					mapkey = 16;
+					break;
+				case 'B': /* \e[B, down arrow */
+					mapkey = 14;
+					break;
+				case 'C': /* \e[C, right arrow */
+					mapkey = 6;
+					break;
+				case 'D': /* \e[D, left arrow */
+					mapkey = 2;
+					break;
+				case '1': /* dropthrough */
+				case '3': /* dropthrough */
+				/* \e[<1,3,4>], may be home, del, end */
+				case '4':
+					mapkey = -1;
+					break;
+				}
+				if (mapkey != -1) {
+					if (mapkey > 0) {
+						escape_data[0] = mapkey;
+						escape_data[1] = '\0';
+					}
+					escape_delay = 2;
+				}
+				continue;
+			} else if (ped - escape_data == 4) {
+				/* \e[<1,3,4><something> */
+				int mapkey = 0;
+				if (key == '~') {
+					switch (escape_data[2]) {
+					case '1': /* \e[1~, home */
+						mapkey = 1;
+						break;
+					case '3': /* \e[3~, del */
+						mapkey = 4;
+						break;
+					case '4': /* \e[4~, end */
+						mapkey = 5;
+						break;
+					}
+				}
+				if (mapkey > 0) {
+					escape_data[0] = mapkey;
+					escape_data[1] = '\0';
+				}
+				escape_delay = 2;
+				continue;
+			}
+		}
+		break;	/* A key to process */
+	}
+	return key;
+}
+
+/*
+ * kdb_read
+ *
+ *	This function reads a string of characters, terminated by
+ *	a newline, or by reaching the end of the supplied buffer,
+ *	from the current kernel debugger console device.
+ * Parameters:
+ *	buffer	- Address of character buffer to receive input characters.
+ *	bufsize - size, in bytes, of the character buffer
+ * Returns:
+ *	Returns a pointer to the buffer containing the received
+ *	character string.  This string will be terminated by a
+ *	newline character.
+ * Locking:
+ *	No locks are required to be held upon entry to this
+ *	function.  It is not reentrant - it relies on the fact
+ *	that while kdb is running on only one "master debug" cpu.
+ * Remarks:
+ *
+ * The buffer size must be >= 2.  A buffer size of 2 means that the caller only
+ * wants a single key.
+ *
+ * An escape key could be the start of a vt100 control sequence such as \e[D
+ * (left arrow) or it could be a character in its own right.  The standard
+ * method for detecting the difference is to wait for 2 seconds to see if there
+ * are any other characters.  kdb is complicated by the lack of a timer service
+ * (interrupts are off), by multiple input sources and by the need to sometimes
+ * return after just one key.  Escape sequence processing has to be done as
+ * states in the polling loop.
+ */
+
+static char *kdb_read(char *buffer, size_t bufsize)
+{
+	char *cp = buffer;
+	char *bufend = buffer+bufsize-2;	/* Reserve space for newline
+						 * and null byte */
+	char *lastchar;
+	char *p_tmp;
+	char tmp;
+	static char tmpbuffer[CMD_BUFLEN];
+	int len = strlen(buffer);
+	int len_tmp;
+	int tab = 0;
+	int count;
+	int i;
+	int diag, dtab_count;
+	int key;
+
+
+	diag = kdbgetintenv("DTABCOUNT", &dtab_count);
+	if (diag)
+		dtab_count = 30;
+
+	if (len > 0) {
+		cp += len;
+		if (*(buffer+len-1) == '\n')
+			cp--;
+	}
+
+	lastchar = cp;
+	*cp = '\0';
+	kdb_printf("%s", buffer);
+poll_again:
+	key = kdb_read_get_key(buffer, bufsize);
+	if (key == -1)
+		return buffer;
+	if (key != 9)
+		tab = 0;
+	switch (key) {
+	case 8: /* backspace */
+		if (cp > buffer) {
+			if (cp < lastchar) {
+				memcpy(tmpbuffer, cp, lastchar - cp);
+				memcpy(cp-1, tmpbuffer, lastchar - cp);
+			}
+			*(--lastchar) = '\0';
+			--cp;
+			kdb_printf("\b%s \r", cp);
+			tmp = *cp;
+			*cp = '\0';
+			kdb_printf(kdb_prompt_str);
+			kdb_printf("%s", buffer);
+			*cp = tmp;
+		}
+		break;
+	case 13: /* enter */
+		*lastchar++ = '\n';
+		*lastchar++ = '\0';
+		if (!KDB_STATE(KGDB_TRANS)) {
+			KDB_STATE_SET(KGDB_TRANS);
+			kdb_printf("%s", buffer);
+		}
+		kdb_printf("\n");
+		return buffer;
+	case 4: /* Del */
+		if (cp < lastchar) {
+			memcpy(tmpbuffer, cp+1, lastchar - cp - 1);
+			memcpy(cp, tmpbuffer, lastchar - cp - 1);
+			*(--lastchar) = '\0';
+			kdb_printf("%s \r", cp);
+			tmp = *cp;
+			*cp = '\0';
+			kdb_printf(kdb_prompt_str);
+			kdb_printf("%s", buffer);
+			*cp = tmp;
+		}
+		break;
+	case 1: /* Home */
+		if (cp > buffer) {
+			kdb_printf("\r");
+			kdb_printf(kdb_prompt_str);
+			cp = buffer;
+		}
+		break;
+	case 5: /* End */
+		if (cp < lastchar) {
+			kdb_printf("%s", cp);
+			cp = lastchar;
+		}
+		break;
+	case 2: /* Left */
+		if (cp > buffer) {
+			kdb_printf("\b");
+			--cp;
+		}
+		break;
+	case 14: /* Down */
+		memset(tmpbuffer, ' ',
+		       strlen(kdb_prompt_str) + (lastchar-buffer));
+		*(tmpbuffer+strlen(kdb_prompt_str) +
+		  (lastchar-buffer)) = '\0';
+		kdb_printf("\r%s\r", tmpbuffer);
+		*lastchar = (char)key;
+		*(lastchar+1) = '\0';
+		return lastchar;
+	case 6: /* Right */
+		if (cp < lastchar) {
+			kdb_printf("%c", *cp);
+			++cp;
+		}
+		break;
+	case 16: /* Up */
+		memset(tmpbuffer, ' ',
+		       strlen(kdb_prompt_str) + (lastchar-buffer));
+		*(tmpbuffer+strlen(kdb_prompt_str) +
+		  (lastchar-buffer)) = '\0';
+		kdb_printf("\r%s\r", tmpbuffer);
+		*lastchar = (char)key;
+		*(lastchar+1) = '\0';
+		return lastchar;
+	case 9: /* Tab */
+		if (tab < 2)
+			++tab;
+		p_tmp = buffer;
+		while (*p_tmp == ' ')
+			p_tmp++;
+		if (p_tmp > cp)
+			break;
+		memcpy(tmpbuffer, p_tmp, cp-p_tmp);
+		*(tmpbuffer + (cp-p_tmp)) = '\0';
+		p_tmp = strrchr(tmpbuffer, ' ');
+		if (p_tmp)
+			++p_tmp;
+		else
+			p_tmp = tmpbuffer;
+		len = strlen(p_tmp);
+		count = kallsyms_symbol_complete(p_tmp,
+						 sizeof(tmpbuffer) -
+						 (p_tmp - tmpbuffer));
+		if (tab == 2 && count > 0) {
+			kdb_printf("\n%d symbols are found.", count);
+			if (count > dtab_count) {
+				count = dtab_count;
+				kdb_printf(" But only first %d symbols will"
+					   " be printed.\nYou can change the"
+					   " environment variable DTABCOUNT.",
+					   count);
+			}
+			kdb_printf("\n");
+			for (i = 0; i < count; i++) {
+				if (kallsyms_symbol_next(p_tmp, i) < 0)
+					break;
+				kdb_printf("%s ", p_tmp);
+				*(p_tmp + len) = '\0';
+			}
+			if (i >= dtab_count)
+				kdb_printf("...");
+			kdb_printf("\n");
+			kdb_printf(kdb_prompt_str);
+			kdb_printf("%s", buffer);
+		} else if (tab != 2 && count > 0) {
+			len_tmp = strlen(p_tmp);
+			strncpy(p_tmp+len_tmp, cp, lastchar-cp+1);
+			len_tmp = strlen(p_tmp);
+			strncpy(cp, p_tmp+len, len_tmp-len + 1);
+			len = len_tmp - len;
+			kdb_printf("%s", cp);
+			cp += len;
+			lastchar += len;
+		}
+		kdb_nextline = 1; /* reset output line number */
+		break;
+	default:
+		if (key >= 32 && lastchar < bufend) {
+			if (cp < lastchar) {
+				memcpy(tmpbuffer, cp, lastchar - cp);
+				memcpy(cp+1, tmpbuffer, lastchar - cp);
+				*++lastchar = '\0';
+				*cp = key;
+				kdb_printf("%s\r", cp);
+				++cp;
+				tmp = *cp;
+				*cp = '\0';
+				kdb_printf(kdb_prompt_str);
+				kdb_printf("%s", buffer);
+				*cp = tmp;
+			} else {
+				*++lastchar = '\0';
+				*cp++ = key;
+				/* The kgdb transition check will hide
+				 * printed characters if we think that
+				 * kgdb is connecting, until the check
+				 * fails */
+				if (!KDB_STATE(KGDB_TRANS)) {
+					if (kgdb_transition_check(buffer))
+						return buffer;
+				} else {
+					kdb_printf("%c", key);
+				}
+			}
+			/* Special escape to kgdb */
+			if (lastchar - buffer >= 5 &&
+			    strcmp(lastchar - 5, "$?#3f") == 0) {
+				kdb_gdb_state_pass(lastchar - 5);
+				strcpy(buffer, "kgdb");
+				KDB_STATE_SET(DOING_KGDB);
+				return buffer;
+			}
+			if (lastchar - buffer >= 11 &&
+			    strcmp(lastchar - 11, "$qSupported") == 0) {
+				kdb_gdb_state_pass(lastchar - 11);
+				strcpy(buffer, "kgdb");
+				KDB_STATE_SET(DOING_KGDB);
+				return buffer;
+			}
+		}
+		break;
+	}
+	goto poll_again;
+}
+
+/*
+ * kdb_getstr
+ *
+ *	Print the prompt string and read a command from the
+ *	input device.
+ *
+ * Parameters:
+ *	buffer	Address of buffer to receive command
+ *	bufsize Size of buffer in bytes
+ *	prompt	Pointer to string to use as prompt string
+ * Returns:
+ *	Pointer to command buffer.
+ * Locking:
+ *	None.
+ * Remarks:
+ *	For SMP kernels, the processor number will be
+ *	substituted for %d, %x or %o in the prompt.
+ */
+
+char *kdb_getstr(char *buffer, size_t bufsize, const char *prompt)
+{
+	if (prompt && kdb_prompt_str != prompt)
+		strncpy(kdb_prompt_str, prompt, CMD_BUFLEN);
+	kdb_printf(kdb_prompt_str);
+	kdb_nextline = 1;	/* Prompt and input resets line number */
+	return kdb_read(buffer, bufsize);
+}
+
+/*
+ * kdb_input_flush
+ *
+ *	Get rid of any buffered console input.
+ *
+ * Parameters:
+ *	none
+ * Returns:
+ *	nothing
+ * Locking:
+ *	none
+ * Remarks:
+ *	Call this function whenever you want to flush input.  If there is any
+ *	outstanding input, it ignores all characters until there has been no
+ *	data for approximately 1ms.
+ */
+
+static void kdb_input_flush(void)
+{
+	get_char_func *f;
+	int res;
+	int flush_delay = 1;
+	while (flush_delay) {
+		flush_delay--;
+empty:
+		touch_nmi_watchdog();
+		for (f = &kdb_poll_funcs[0]; *f; ++f) {
+			res = (*f)();
+			if (res != -1) {
+				flush_delay = 1;
+				goto empty;
+			}
+		}
+		if (flush_delay)
+			mdelay(1);
+	}
+}
+
+/*
+ * kdb_printf
+ *
+ *	Print a string to the output device(s).
+ *
+ * Parameters:
+ *	printf-like format and optional args.
+ * Returns:
+ *	0
+ * Locking:
+ *	None.
+ * Remarks:
+ *	use 'kdbcons->write()' to avoid polluting 'log_buf' with
+ *	kdb output.
+ *
+ *  If the user is doing a cmd args | grep srch
+ *  then kdb_grepping_flag is set.
+ *  In that case we need to accumulate full lines (ending in \n) before
+ *  searching for the pattern.
+ */
+
+static char kdb_buffer[256];	/* A bit too big to go on stack */
+static char *next_avail = kdb_buffer;
+static int  size_avail;
+static int  suspend_grep;
+
+/*
+ * search arg1 to see if it contains arg2
+ * (kdmain.c provides flags for ^pat and pat$)
+ *
+ * return 1 for found, 0 for not found
+ */
+static int kdb_search_string(char *searched, char *searchfor)
+{
+	char firstchar, *cp;
+	int len1, len2;
+
+	/* not counting the newline at the end of "searched" */
+	len1 = strlen(searched)-1;
+	len2 = strlen(searchfor);
+	if (len1 < len2)
+		return 0;
+	if (kdb_grep_leading && kdb_grep_trailing && len1 != len2)
+		return 0;
+	if (kdb_grep_leading) {
+		if (!strncmp(searched, searchfor, len2))
+			return 1;
+	} else if (kdb_grep_trailing) {
+		if (!strncmp(searched+len1-len2, searchfor, len2))
+			return 1;
+	} else {
+		firstchar = *searchfor;
+		cp = searched;
+		while ((cp = strchr(cp, firstchar))) {
+			if (!strncmp(cp, searchfor, len2))
+				return 1;
+			cp++;
+		}
+	}
+	return 0;
+}
+
+int vkdb_printf(enum kdb_msgsrc src, const char *fmt, va_list ap)
+{
+	int diag;
+	int linecount;
+	int colcount;
+	int logging, saved_loglevel = 0;
+	int saved_trap_printk;
+	int got_printf_lock = 0;
+	int retlen = 0;
+	int fnd, len;
+	char *cp, *cp2, *cphold = NULL, replaced_byte = ' ';
+	char *moreprompt = "more> ";
+	struct console *c = console_drivers;
+	static DEFINE_SPINLOCK(kdb_printf_lock);
+	unsigned long uninitialized_var(flags);
+
+	preempt_disable();
+	saved_trap_printk = kdb_trap_printk;
+	kdb_trap_printk = 0;
+
+	/* Serialize kdb_printf if multiple cpus try to write at once.
+	 * But if any cpu goes recursive in kdb, just print the output,
+	 * even if it is interleaved with any other text.
+	 */
+	if (!KDB_STATE(PRINTF_LOCK)) {
+		KDB_STATE_SET(PRINTF_LOCK);
+		spin_lock_irqsave(&kdb_printf_lock, flags);
+		got_printf_lock = 1;
+		atomic_inc(&kdb_event);
+	} else {
+		__acquire(kdb_printf_lock);
+	}
+
+	diag = kdbgetintenv("LINES", &linecount);
+	if (diag || linecount <= 1)
+		linecount = 24;
+
+	diag = kdbgetintenv("COLUMNS", &colcount);
+	if (diag || colcount <= 1)
+		colcount = 80;
+
+	diag = kdbgetintenv("LOGGING", &logging);
+	if (diag)
+		logging = 0;
+
+	if (!kdb_grepping_flag || suspend_grep) {
+		/* normally, every vsnprintf starts a new buffer */
+		next_avail = kdb_buffer;
+		size_avail = sizeof(kdb_buffer);
+	}
+	vsnprintf(next_avail, size_avail, fmt, ap);
+
+	/*
+	 * If kdb_parse() found that the command was cmd xxx | grep yyy
+	 * then kdb_grepping_flag is set, and kdb_grep_string contains yyy
+	 *
+	 * Accumulate the print data up to a newline before searching it.
+	 * (vsnprintf does null-terminate the string that it generates)
+	 */
+
+	/* skip the search if prints are temporarily unconditional */
+	if (!suspend_grep && kdb_grepping_flag) {
+		cp = strchr(kdb_buffer, '\n');
+		if (!cp) {
+			/*
+			 * Special cases that don't end with newlines
+			 * but should be written without one:
+			 *   The "[nn]kdb> " prompt should
+			 *   appear at the front of the buffer.
+			 *
+			 *   The "[nn]more " prompt should also be
+			 *     (MOREPROMPT -> moreprompt)
+			 *   written *   but we print that ourselves,
+			 *   we set the suspend_grep flag to make
+			 *   it unconditional.
+			 *
+			 */
+			if (next_avail == kdb_buffer) {
+				/*
+				 * these should occur after a newline,
+				 * so they will be at the front of the
+				 * buffer
+				 */
+				cp2 = kdb_buffer;
+				len = strlen(kdb_prompt_str);
+				if (!strncmp(cp2, kdb_prompt_str, len)) {
+					/*
+					 * We're about to start a new
+					 * command, so we can go back
+					 * to normal mode.
+					 */
+					kdb_grepping_flag = 0;
+					goto kdb_printit;
+				}
+			}
+			/* no newline; don't search/write the buffer
+			   until one is there */
+			len = strlen(kdb_buffer);
+			next_avail = kdb_buffer + len;
+			size_avail = sizeof(kdb_buffer) - len;
+			goto kdb_print_out;
+		}
+
+		/*
+		 * The newline is present; print through it or discard
+		 * it, depending on the results of the search.
+		 */
+		cp++;	 	     /* to byte after the newline */
+		replaced_byte = *cp; /* remember what/where it was */
+		cphold = cp;
+		*cp = '\0';	     /* end the string for our search */
+
+		/*
+		 * We now have a newline at the end of the string
+		 * Only continue with this output if it contains the
+		 * search string.
+		 */
+		fnd = kdb_search_string(kdb_buffer, kdb_grep_string);
+		if (!fnd) {
+			/*
+			 * At this point the complete line at the start
+			 * of kdb_buffer can be discarded, as it does
+			 * not contain what the user is looking for.
+			 * Shift the buffer left.
+			 */
+			*cphold = replaced_byte;
+			strcpy(kdb_buffer, cphold);
+			len = strlen(kdb_buffer);
+			next_avail = kdb_buffer + len;
+			size_avail = sizeof(kdb_buffer) - len;
+			goto kdb_print_out;
+		}
+		if (kdb_grepping_flag >= KDB_GREPPING_FLAG_SEARCH)
+			/*
+			 * This was a interactive search (using '/' at more
+			 * prompt) and it has completed. Clear the flag.
+			 */
+			kdb_grepping_flag = 0;
+		/*
+		 * at this point the string is a full line and
+		 * should be printed, up to the null.
+		 */
+	}
+kdb_printit:
+
+	/*
+	 * Write to all consoles.
+	 */
+	retlen = strlen(kdb_buffer);
+	cp = (char *) printk_skip_level(kdb_buffer);
+	if (!dbg_kdb_mode && kgdb_connected) {
+		gdbstub_msg_write(cp, retlen - (cp - kdb_buffer));
+	} else {
+		if (dbg_io_ops && !dbg_io_ops->is_console) {
+			len = retlen - (cp - kdb_buffer);
+			cp2 = cp;
+			while (len--) {
+				dbg_io_ops->write_char(*cp2);
+				cp2++;
+			}
+		}
+		while (c) {
+			c->write(c, cp, retlen - (cp - kdb_buffer), 7); /* 7 == KERN_DEBUG */
+			touch_nmi_watchdog();
+			c = c->next;
+		}
+	}
+	if (logging) {
+		saved_loglevel = console_loglevel;
+		console_loglevel = CONSOLE_LOGLEVEL_SILENT;
+		if (printk_get_level(kdb_buffer) || src == KDB_MSGSRC_PRINTK)
+			printk("%s", kdb_buffer);
+		else
+			pr_info("%s", kdb_buffer);
+	}
+
+	if (KDB_STATE(PAGER)) {
+		/*
+		 * Check printed string to decide how to bump the
+		 * kdb_nextline to control when the more prompt should
+		 * show up.
+		 */
+		int got = 0;
+		len = retlen;
+		while (len--) {
+			if (kdb_buffer[len] == '\n') {
+				kdb_nextline++;
+				got = 0;
+			} else if (kdb_buffer[len] == '\r') {
+				got = 0;
+			} else {
+				got++;
+			}
+		}
+		kdb_nextline += got / (colcount + 1);
+	}
+
+	/* check for having reached the LINES number of printed lines */
+	if (kdb_nextline >= linecount) {
+		char buf1[16] = "";
+
+		/* Watch out for recursion here.  Any routine that calls
+		 * kdb_printf will come back through here.  And kdb_read
+		 * uses kdb_printf to echo on serial consoles ...
+		 */
+		kdb_nextline = 1;	/* In case of recursion */
+
+		/*
+		 * Pause until cr.
+		 */
+		moreprompt = kdbgetenv("MOREPROMPT");
+		if (moreprompt == NULL)
+			moreprompt = "more> ";
+
+		kdb_input_flush();
+		c = console_drivers;
+
+		if (dbg_io_ops && !dbg_io_ops->is_console) {
+			len = strlen(moreprompt);
+			cp = moreprompt;
+			while (len--) {
+				dbg_io_ops->write_char(*cp);
+				cp++;
+			}
+		}
+		while (c) {
+			c->write(c, moreprompt, strlen(moreprompt), 7); /* 7 == KERN_DEBUG */
+			touch_nmi_watchdog();
+			c = c->next;
+		}
+
+		if (logging)
+			printk("%s", moreprompt);
+
+		kdb_read(buf1, 2); /* '2' indicates to return
+				    * immediately after getting one key. */
+		kdb_nextline = 1;	/* Really set output line 1 */
+
+		/* empty and reset the buffer: */
+		kdb_buffer[0] = '\0';
+		next_avail = kdb_buffer;
+		size_avail = sizeof(kdb_buffer);
+		if ((buf1[0] == 'q') || (buf1[0] == 'Q')) {
+			/* user hit q or Q */
+			KDB_FLAG_SET(CMD_INTERRUPT); /* command interrupted */
+			KDB_STATE_CLEAR(PAGER);
+			/* end of command output; back to normal mode */
+			kdb_grepping_flag = 0;
+			kdb_printf("\n");
+		} else if (buf1[0] == ' ') {
+			kdb_printf("\r");
+			suspend_grep = 1; /* for this recursion */
+		} else if (buf1[0] == '\n') {
+			kdb_nextline = linecount - 1;
+			kdb_printf("\r");
+			suspend_grep = 1; /* for this recursion */
+		} else if (buf1[0] == '/' && !kdb_grepping_flag) {
+			kdb_printf("\r");
+			kdb_getstr(kdb_grep_string, KDB_GREP_STRLEN,
+				   kdbgetenv("SEARCHPROMPT") ?: "search> ");
+			*strchrnul(kdb_grep_string, '\n') = '\0';
+			kdb_grepping_flag += KDB_GREPPING_FLAG_SEARCH;
+			suspend_grep = 1; /* for this recursion */
+		} else if (buf1[0] && buf1[0] != '\n') {
+			/* user hit something other than enter */
+			suspend_grep = 1; /* for this recursion */
+			if (buf1[0] != '/')
+				kdb_printf(
+				    "\nOnly 'q', 'Q' or '/' are processed at "
+				    "more prompt, input ignored\n");
+			else
+				kdb_printf("\n'/' cannot be used during | "
+					   "grep filtering, input ignored\n");
+		} else if (kdb_grepping_flag) {
+			/* user hit enter */
+			suspend_grep = 1; /* for this recursion */
+			kdb_printf("\n");
+		}
+		kdb_input_flush();
+	}
+
+	/*
+	 * For grep searches, shift the printed string left.
+	 *  replaced_byte contains the character that was overwritten with
+	 *  the terminating null, and cphold points to the null.
+	 * Then adjust the notion of available space in the buffer.
+	 */
+	if (kdb_grepping_flag && !suspend_grep) {
+		*cphold = replaced_byte;
+		strcpy(kdb_buffer, cphold);
+		len = strlen(kdb_buffer);
+		next_avail = kdb_buffer + len;
+		size_avail = sizeof(kdb_buffer) - len;
+	}
+
+kdb_print_out:
+	suspend_grep = 0; /* end of what may have been a recursive call */
+	if (logging)
+		console_loglevel = saved_loglevel;
+	if (KDB_STATE(PRINTF_LOCK) && got_printf_lock) {
+		got_printf_lock = 0;
+		spin_unlock_irqrestore(&kdb_printf_lock, flags);
+		KDB_STATE_CLEAR(PRINTF_LOCK);
+		atomic_dec(&kdb_event);
+	} else {
+		__release(kdb_printf_lock);
+	}
+	kdb_trap_printk = saved_trap_printk;
+	preempt_enable();
+	return retlen;
+}
+
+int kdb_printf(const char *fmt, ...)
+{
+	va_list ap;
+	int r;
+
+	va_start(ap, fmt);
+	r = vkdb_printf(KDB_MSGSRC_INTERNAL, fmt, ap);
+	va_end(ap);
+
+	return r;
+}
+EXPORT_SYMBOL_GPL(kdb_printf);