kgdboc,keyboard: Keyboard driver for kdb with kgdb

This patch adds in the kdb PS/2 keyboard driver. This was mostly a direct port from the original kdb where I cleaned up the code against checkpatch.pl and added the glue to stitch it into kgdb. This patch also enables early kdb debug via kgdbwait and the keyboard. All the access to configure kdb using either a serial console or the keyboard is done via kgdboc. If you want to use only the keyboard and want to break in early you would add to your kernel command arguments: kgdboc=kbd kgdbwait If you wanted serial and or the keyboard access you could use: kgdboc=kbd,ttyS0 You can also configure kgdboc as a kernel module or at run time with the sysfs where you can activate and deactivate kgdb. Turn it on: echo kbd,ttyS0 > /sys/module/kgdboc/parameters/kgdboc Turn it off: echo "" > /sys/module/kgdboc/parameters/kgdboc Signed-off-by: Jason Wessel <jason.wessel@windriver.com> Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

kgdboc,keyboard: Keyboard driver for kdb with kgdb
This patch adds in the kdb PS/2 keyboard driver. This was mostly a direct port from the original kdb where I cleaned up the code against checkpatch.pl and added the glue to stitch it into kgdb. This patch also enables early kdb debug via kgdbwait and the keyboard. All the access to configure kdb using either a serial console or the keyboard is done via kgdboc. If you want to use only the keyboard and want to break in early you would add to your kernel command arguments: kgdboc=kbd kgdbwait If you wanted serial and or the keyboard access you could use: kgdboc=kbd,ttyS0 You can also configure kgdboc as a kernel module or at run time with the sysfs where you can activate and deactivate kgdb. Turn it on: echo kbd,ttyS0 > /sys/module/kgdboc/parameters/kgdboc Turn it off: echo "" > /sys/module/kgdboc/parameters/kgdboc Signed-off-by: Jason Wessel <jason.wessel@windriver.com> Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Jason Wessel
1 parent a0de055cf6
Showing 5 changed files with 279 additions and 10 deletions Side-by-side Diff
Documentation/kernel-parameters.txt
drivers/serial/kgdboc.c
kernel/debug/kdb/Makefile
kernel/debug/kdb/kdb_keyboard.c
lib/Kconfig.kgdb
@@ -1121,9 +1121,11 @@
 			zone if it does not.
  
 	kgdboc=		[HW] kgdb over consoles.
-			Requires a tty driver that supports console polling.
-			(only serial supported for now)
-			Format: <serial_device>[,baud]
+			Requires a tty driver that supports console polling,
+			or a supported polling keyboard driver (non-usb).
+			Serial only format: <serial_device>[,baud]
+			keyboard only format: kbd
+			keyboard and serial format: kbd,<serial_device>[,baud]
  
 	kmac=		[MIPS] korina ethernet MAC address.
 			Configure the RouterBoard 532 series on-chip
@@ -14,6 +14,7 @@
 #include <linux/kernel.h>
 #include <linux/ctype.h>
 #include <linux/kgdb.h>
+#include <linux/kdb.h>
 #include <linux/tty.h>
  
 #define MAX_CONFIG_LEN		40
@@ -32,6 +33,40 @@
 static struct tty_driver	*kgdb_tty_driver;
 static int			kgdb_tty_line;
  
+#ifdef CONFIG_KDB_KEYBOARD
+static int kgdboc_register_kbd(char **cptr)
+{
+	if (strncmp(*cptr, "kbd", 3) == 0) {
+		if (kdb_poll_idx < KDB_POLL_FUNC_MAX) {
+			kdb_poll_funcs[kdb_poll_idx] = kdb_get_kbd_char;
+			kdb_poll_idx++;
+			if (cptr[0][3] == ',')
+				*cptr += 4;
+			else
+				return 1;
+		}
+	}
+	return 0;
+}
+
+static void kgdboc_unregister_kbd(void)
+{
+	int i;
+
+	for (i = 0; i < kdb_poll_idx; i++) {
+		if (kdb_poll_funcs[i] == kdb_get_kbd_char) {
+			kdb_poll_idx--;
+			kdb_poll_funcs[i] = kdb_poll_funcs[kdb_poll_idx];
+			kdb_poll_funcs[kdb_poll_idx] = NULL;
+			i--;
+		}
+	}
+}
+#else /* ! CONFIG_KDB_KEYBOARD */
+#define kgdboc_register_kbd(x) 0
+#define kgdboc_unregister_kbd()
+#endif /* ! CONFIG_KDB_KEYBOARD */
+
 static int kgdboc_option_setup(char *opt)
 {
 	if (strlen(opt) > MAX_CONFIG_LEN) {
  
  
  
  
@@ -45,25 +80,38 @@
  
 __setup("kgdboc=", kgdboc_option_setup);
  
+static void cleanup_kgdboc(void)
+{
+	kgdboc_unregister_kbd();
+	if (configured == 1)
+		kgdb_unregister_io_module(&kgdboc_io_ops);
+}
+
 static int configure_kgdboc(void)
 {
 	struct tty_driver *p;
 	int tty_line = 0;
 	int err;
+	char *cptr = config;
  
 	err = kgdboc_option_setup(config);
 	if (err || !strlen(config) || isspace(config[0]))
 		goto noconfig;
  
 	err = -ENODEV;
+	kgdb_tty_driver = NULL;
  
-	p = tty_find_polling_driver(config, &tty_line);
+	if (kgdboc_register_kbd(&cptr))
+		goto do_register;
+
+	p = tty_find_polling_driver(cptr, &tty_line);
 	if (!p)
 		goto noconfig;
  
 	kgdb_tty_driver = p;
 	kgdb_tty_line = tty_line;
  
+do_register:
 	err = kgdb_register_io_module(&kgdboc_io_ops);
 	if (err)
 		goto noconfig;
@@ -75,6 +123,7 @@
 noconfig:
 	config[0] = 0;
 	configured = 0;
+	cleanup_kgdboc();
  
 	return err;
 }
  
  
@@ -88,20 +137,18 @@
 	return configure_kgdboc();
 }
  
-static void cleanup_kgdboc(void)
-{
-	if (configured == 1)
-		kgdb_unregister_io_module(&kgdboc_io_ops);
-}
-
 static int kgdboc_get_char(void)
 {
+	if (!kgdb_tty_driver)
+		return -1;
 	return kgdb_tty_driver->ops->poll_get_char(kgdb_tty_driver,
 						kgdb_tty_line);
 }
  
 static void kgdboc_put_char(u8 chr)
 {
+	if (!kgdb_tty_driver)
+		return;
 	kgdb_tty_driver->ops->poll_put_char(kgdb_tty_driver,
 					kgdb_tty_line, chr);
 }
@@ -8,6 +8,7 @@
  
 CCVERSION	:= $(shell $(CC) -v 2>&1 | sed -ne '$$p')
 obj-y := kdb_io.o kdb_main.o kdb_support.o kdb_bt.o gen-kdb_cmds.o kdb_bp.o kdb_debugger.o
+obj-$(CONFIG_KDB_KEYBOARD)    += kdb_keyboard.o
  
 clean-files := gen-kdb_cmds.c
  
+/*
+ * Kernel Debugger Architecture Dependent Console I/O handler
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.
+ *
+ * Copyright (c) 1999-2006 Silicon Graphics, Inc.  All Rights Reserved.
+ * Copyright (c) 2009 Wind River Systems, Inc.  All Rights Reserved.
+ */
+
+#include <linux/kdb.h>
+#include <linux/keyboard.h>
+#include <linux/ctype.h>
+#include <linux/module.h>
+#include <linux/io.h>
+
+/* Keyboard Controller Registers on normal PCs. */
+
+#define KBD_STATUS_REG		0x64	/* Status register (R) */
+#define KBD_DATA_REG		0x60	/* Keyboard data register (R/W) */
+
+/* Status Register Bits */
+
+#define KBD_STAT_OBF 		0x01	/* Keyboard output buffer full */
+#define KBD_STAT_MOUSE_OBF	0x20	/* Mouse output buffer full */
+
+static int kbd_exists;
+
+/*
+ * Check if the keyboard controller has a keypress for us.
+ * Some parts (Enter Release, LED change) are still blocking polled here,
+ * but hopefully they are all short.
+ */
+int kdb_get_kbd_char(void)
+{
+	int scancode, scanstatus;
+	static int shift_lock;	/* CAPS LOCK state (0-off, 1-on) */
+	static int shift_key;	/* Shift next keypress */
+	static int ctrl_key;
+	u_short keychar;
+
+	if (KDB_FLAG(NO_I8042) || KDB_FLAG(NO_VT_CONSOLE) ||
+	    (inb(KBD_STATUS_REG) == 0xff && inb(KBD_DATA_REG) == 0xff)) {
+		kbd_exists = 0;
+		return -1;
+	}
+	kbd_exists = 1;
+
+	if ((inb(KBD_STATUS_REG) & KBD_STAT_OBF) == 0)
+		return -1;
+
+	/*
+	 * Fetch the scancode
+	 */
+	scancode = inb(KBD_DATA_REG);
+	scanstatus = inb(KBD_STATUS_REG);
+
+	/*
+	 * Ignore mouse events.
+	 */
+	if (scanstatus & KBD_STAT_MOUSE_OBF)
+		return -1;
+
+	/*
+	 * Ignore release, trigger on make
+	 * (except for shift keys, where we want to
+	 *  keep the shift state so long as the key is
+	 *  held down).
+	 */
+
+	if (((scancode&0x7f) == 0x2a) || ((scancode&0x7f) == 0x36)) {
+		/*
+		 * Next key may use shift table
+		 */
+		if ((scancode & 0x80) == 0)
+			shift_key = 1;
+		else
+			shift_key = 0;
+		return -1;
+	}
+
+	if ((scancode&0x7f) == 0x1d) {
+		/*
+		 * Left ctrl key
+		 */
+		if ((scancode & 0x80) == 0)
+			ctrl_key = 1;
+		else
+			ctrl_key = 0;
+		return -1;
+	}
+
+	if ((scancode & 0x80) != 0)
+		return -1;
+
+	scancode &= 0x7f;
+
+	/*
+	 * Translate scancode
+	 */
+
+	if (scancode == 0x3a) {
+		/*
+		 * Toggle caps lock
+		 */
+		shift_lock ^= 1;
+
+#ifdef	KDB_BLINK_LED
+		kdb_toggleled(0x4);
+#endif
+		return -1;
+	}
+
+	if (scancode == 0x0e) {
+		/*
+		 * Backspace
+		 */
+		return 8;
+	}
+
+	/* Special Key */
+	switch (scancode) {
+	case 0xF: /* Tab */
+		return 9;
+	case 0x53: /* Del */
+		return 4;
+	case 0x47: /* Home */
+		return 1;
+	case 0x4F: /* End */
+		return 5;
+	case 0x4B: /* Left */
+		return 2;
+	case 0x48: /* Up */
+		return 16;
+	case 0x50: /* Down */
+		return 14;
+	case 0x4D: /* Right */
+		return 6;
+	}
+
+	if (scancode == 0xe0)
+		return -1;
+
+	/*
+	 * For Japanese 86/106 keyboards
+	 * 	See comment in drivers/char/pc_keyb.c.
+	 * 	- Masahiro Adegawa
+	 */
+	if (scancode == 0x73)
+		scancode = 0x59;
+	else if (scancode == 0x7d)
+		scancode = 0x7c;
+
+	if (!shift_lock && !shift_key && !ctrl_key) {
+		keychar = plain_map[scancode];
+	} else if ((shift_lock || shift_key) && key_maps[1]) {
+		keychar = key_maps[1][scancode];
+	} else if (ctrl_key && key_maps[4]) {
+		keychar = key_maps[4][scancode];
+	} else {
+		keychar = 0x0020;
+		kdb_printf("Unknown state/scancode (%d)\n", scancode);
+	}
+	keychar &= 0x0fff;
+	if (keychar == '\t')
+		keychar = ' ';
+	switch (KTYP(keychar)) {
+	case KT_LETTER:
+	case KT_LATIN:
+		if (isprint(keychar))
+			break;		/* printable characters */
+		/* drop through */
+	case KT_SPEC:
+		if (keychar == K_ENTER)
+			break;
+		/* drop through */
+	default:
+		return -1;	/* ignore unprintables */
+	}
+
+	if ((scancode & 0x7f) == 0x1c) {
+		/*
+		 * enter key.  All done.  Absorb the release scancode.
+		 */
+		while ((inb(KBD_STATUS_REG) & KBD_STAT_OBF) == 0)
+			;
+
+		/*
+		 * Fetch the scancode
+		 */
+		scancode = inb(KBD_DATA_REG);
+		scanstatus = inb(KBD_STATUS_REG);
+
+		while (scanstatus & KBD_STAT_MOUSE_OBF) {
+			scancode = inb(KBD_DATA_REG);
+			scanstatus = inb(KBD_STATUS_REG);
+		}
+
+		if (scancode != 0x9c) {
+			/*
+			 * Wasn't an enter-release,  why not?
+			 */
+			kdb_printf("kdb: expected enter got 0x%x status 0x%x\n",
+			       scancode, scanstatus);
+		}
+
+		return 13;
+	}
+
+	return keychar & 0xff;
+}
+EXPORT_SYMBOL_GPL(kdb_get_kbd_char);
@@ -63,5 +63,12 @@
 	help
 	  KDB frontend for kernel
  
+config KDB_KEYBOARD
+	bool "KGDB_KDB: keyboard as input device"
+	depends on VT && KGDB_KDB
+	default n
+	help
+	  KDB can use a PS/2 type keyboard for an input device
+
 endif # KGDB
...	...	@@ -1121,9 +1121,11 @@
1121	1121	zone if it does not.
1122	1122
1123	1123	kgdboc= [HW] kgdb over consoles.
1124		- Requires a tty driver that supports console polling.
1125		- (only serial supported for now)
1126		- Format: <serial_device>[,baud]
	1124	+ Requires a tty driver that supports console polling,
	1125	+ or a supported polling keyboard driver (non-usb).
	1126	+ Serial only format: <serial_device>[,baud]
	1127	+ keyboard only format: kbd
	1128	+ keyboard and serial format: kbd,<serial_device>[,baud]
1127	1129
1128	1130	kmac= [MIPS] korina ethernet MAC address.
1129	1131	Configure the RouterBoard 532 series on-chip
...	...	@@ -14,6 +14,7 @@
14	14	#include <linux/kernel.h>
15	15	#include <linux/ctype.h>
16	16	#include <linux/kgdb.h>
	17	+#include <linux/kdb.h>
17	18	#include <linux/tty.h>
18	19
19	20	#define MAX_CONFIG_LEN 40
...	...	@@ -32,6 +33,40 @@
32	33	static struct tty_driver *kgdb_tty_driver;
33	34	static int kgdb_tty_line;
34	35
	36	+#ifdef CONFIG_KDB_KEYBOARD
	37	+static int kgdboc_register_kbd(char **cptr)
	38	+{
	39	+ if (strncmp(*cptr, "kbd", 3) == 0) {
	40	+ if (kdb_poll_idx < KDB_POLL_FUNC_MAX) {
	41	+ kdb_poll_funcs[kdb_poll_idx] = kdb_get_kbd_char;
	42	+ kdb_poll_idx++;
	43	+ if (cptr[0][3] == ',')
	44	+ *cptr += 4;
	45	+ else
	46	+ return 1;
	47	+ }
	48	+ }
	49	+ return 0;
	50	+}
	51	+
	52	+static void kgdboc_unregister_kbd(void)
	53	+{
	54	+ int i;
	55	+
	56	+ for (i = 0; i < kdb_poll_idx; i++) {
	57	+ if (kdb_poll_funcs[i] == kdb_get_kbd_char) {
	58	+ kdb_poll_idx--;
	59	+ kdb_poll_funcs[i] = kdb_poll_funcs[kdb_poll_idx];
	60	+ kdb_poll_funcs[kdb_poll_idx] = NULL;
	61	+ i--;
	62	+ }
	63	+ }
	64	+}
	65	+#else /* ! CONFIG_KDB_KEYBOARD */
	66	+#define kgdboc_register_kbd(x) 0
	67	+#define kgdboc_unregister_kbd()
	68	+#endif /* ! CONFIG_KDB_KEYBOARD */
	69	+
35	70	static int kgdboc_option_setup(char *opt)
36	71	{
37	72	if (strlen(opt) > MAX_CONFIG_LEN) {
38	73
39	74
40	75
41	76
...	...	@@ -45,25 +80,38 @@
45	80
46	81	__setup("kgdboc=", kgdboc_option_setup);
47	82
	83	+static void cleanup_kgdboc(void)
	84	+{
	85	+ kgdboc_unregister_kbd();
	86	+ if (configured == 1)
	87	+ kgdb_unregister_io_module(&kgdboc_io_ops);
	88	+}
	89	+
48	90	static int configure_kgdboc(void)
49	91	{
50	92	struct tty_driver *p;
51	93	int tty_line = 0;
52	94	int err;
	95	+ char *cptr = config;
53	96
54	97	err = kgdboc_option_setup(config);
55	98	if (err \|\| !strlen(config) \|\| isspace(config[0]))
56	99	goto noconfig;
57	100
58	101	err = -ENODEV;
	102	+ kgdb_tty_driver = NULL;
59	103
60		- p = tty_find_polling_driver(config, &tty_line);
	104	+ if (kgdboc_register_kbd(&cptr))
	105	+ goto do_register;
	106	+
	107	+ p = tty_find_polling_driver(cptr, &tty_line);
61	108	if (!p)
62	109	goto noconfig;
63	110
64	111	kgdb_tty_driver = p;
65	112	kgdb_tty_line = tty_line;
66	113
	114	+do_register:
67	115	err = kgdb_register_io_module(&kgdboc_io_ops);
68	116	if (err)
69	117	goto noconfig;
...	...	@@ -75,6 +123,7 @@
75	123	noconfig:
76	124	config[0] = 0;
77	125	configured = 0;
	126	+ cleanup_kgdboc();
78	127
79	128	return err;
80	129	}
81	130
82	131
...	...	@@ -88,20 +137,18 @@
88	137	return configure_kgdboc();
89	138	}
90	139
91		-static void cleanup_kgdboc(void)
92		-{
93		- if (configured == 1)
94		- kgdb_unregister_io_module(&kgdboc_io_ops);
95		-}
96		-
97	140	static int kgdboc_get_char(void)
98	141	{
	142	+ if (!kgdb_tty_driver)
	143	+ return -1;
99	144	return kgdb_tty_driver->ops->poll_get_char(kgdb_tty_driver,
100	145	kgdb_tty_line);
101	146	}
102	147
103	148	static void kgdboc_put_char(u8 chr)
104	149	{
	150	+ if (!kgdb_tty_driver)
	151	+ return;
105	152	kgdb_tty_driver->ops->poll_put_char(kgdb_tty_driver,
106	153	kgdb_tty_line, chr);
107	154	}
...	...	@@ -8,6 +8,7 @@
8	8
9	9	CCVERSION := $(shell $(CC) -v 2>&1 \| sed -ne '$$p')
10	10	obj-y := kdb_io.o kdb_main.o kdb_support.o kdb_bt.o gen-kdb_cmds.o kdb_bp.o kdb_debugger.o
	11	+obj-$(CONFIG_KDB_KEYBOARD) += kdb_keyboard.o
11	12
12	13	clean-files := gen-kdb_cmds.c
13	14
	1	+/*
	2	+ * Kernel Debugger Architecture Dependent Console I/O handler
	3	+ *
	4	+ * This file is subject to the terms and conditions of the GNU General Public
	5	+ * License.
	6	+ *
	7	+ * Copyright (c) 1999-2006 Silicon Graphics, Inc. All Rights Reserved.
	8	+ * Copyright (c) 2009 Wind River Systems, Inc. All Rights Reserved.
	9	+ */
	10	+
	11	+#include <linux/kdb.h>
	12	+#include <linux/keyboard.h>
	13	+#include <linux/ctype.h>
	14	+#include <linux/module.h>
	15	+#include <linux/io.h>
	16	+
	17	+/* Keyboard Controller Registers on normal PCs. */
	18	+
	19	+#define KBD_STATUS_REG 0x64 /* Status register (R) */
	20	+#define KBD_DATA_REG 0x60 /* Keyboard data register (R/W) */
	21	+
	22	+/* Status Register Bits */
	23	+
	24	+#define KBD_STAT_OBF 0x01 /* Keyboard output buffer full */
	25	+#define KBD_STAT_MOUSE_OBF 0x20 /* Mouse output buffer full */
	26	+
	27	+static int kbd_exists;
	28	+
	29	+/*
	30	+ * Check if the keyboard controller has a keypress for us.
	31	+ * Some parts (Enter Release, LED change) are still blocking polled here,
	32	+ * but hopefully they are all short.
	33	+ */
	34	+int kdb_get_kbd_char(void)
	35	+{
	36	+ int scancode, scanstatus;
	37	+ static int shift_lock; /* CAPS LOCK state (0-off, 1-on) */
	38	+ static int shift_key; /* Shift next keypress */
	39	+ static int ctrl_key;
	40	+ u_short keychar;
	41	+
	42	+ if (KDB_FLAG(NO_I8042) \|\| KDB_FLAG(NO_VT_CONSOLE) \|\|
	43	+ (inb(KBD_STATUS_REG) == 0xff && inb(KBD_DATA_REG) == 0xff)) {
	44	+ kbd_exists = 0;
	45	+ return -1;
	46	+ }
	47	+ kbd_exists = 1;
	48	+
	49	+ if ((inb(KBD_STATUS_REG) & KBD_STAT_OBF) == 0)
	50	+ return -1;
	51	+
	52	+ /*
	53	+ * Fetch the scancode
	54	+ */
	55	+ scancode = inb(KBD_DATA_REG);
	56	+ scanstatus = inb(KBD_STATUS_REG);
	57	+
	58	+ /*
	59	+ * Ignore mouse events.
	60	+ */
	61	+ if (scanstatus & KBD_STAT_MOUSE_OBF)
	62	+ return -1;
	63	+
	64	+ /*
	65	+ * Ignore release, trigger on make
	66	+ * (except for shift keys, where we want to
	67	+ * keep the shift state so long as the key is
	68	+ * held down).
	69	+ */
	70	+
	71	+ if (((scancode&0x7f) == 0x2a) \|\| ((scancode&0x7f) == 0x36)) {
	72	+ /*
	73	+ * Next key may use shift table
	74	+ */
	75	+ if ((scancode & 0x80) == 0)
	76	+ shift_key = 1;
	77	+ else
	78	+ shift_key = 0;
	79	+ return -1;
	80	+ }
	81	+
	82	+ if ((scancode&0x7f) == 0x1d) {
	83	+ /*
	84	+ * Left ctrl key
	85	+ */
	86	+ if ((scancode & 0x80) == 0)
	87	+ ctrl_key = 1;
	88	+ else
	89	+ ctrl_key = 0;
	90	+ return -1;
	91	+ }
	92	+
	93	+ if ((scancode & 0x80) != 0)
	94	+ return -1;
	95	+
	96	+ scancode &= 0x7f;
	97	+
	98	+ /*
	99	+ * Translate scancode
	100	+ */
	101	+
	102	+ if (scancode == 0x3a) {
	103	+ /*
	104	+ * Toggle caps lock
	105	+ */
	106	+ shift_lock ^= 1;
	107	+
	108	+#ifdef KDB_BLINK_LED
	109	+ kdb_toggleled(0x4);
	110	+#endif
	111	+ return -1;
	112	+ }
	113	+
	114	+ if (scancode == 0x0e) {
	115	+ /*
	116	+ * Backspace
	117	+ */
	118	+ return 8;
	119	+ }
	120	+
	121	+ /* Special Key */
	122	+ switch (scancode) {
	123	+ case 0xF: /* Tab */
	124	+ return 9;
	125	+ case 0x53: /* Del */
	126	+ return 4;
	127	+ case 0x47: /* Home */
	128	+ return 1;
	129	+ case 0x4F: /* End */
	130	+ return 5;
	131	+ case 0x4B: /* Left */
	132	+ return 2;
	133	+ case 0x48: /* Up */
	134	+ return 16;
	135	+ case 0x50: /* Down */
	136	+ return 14;
	137	+ case 0x4D: /* Right */
	138	+ return 6;
	139	+ }
	140	+
	141	+ if (scancode == 0xe0)
	142	+ return -1;
	143	+
	144	+ /*
	145	+ * For Japanese 86/106 keyboards
	146	+ * See comment in drivers/char/pc_keyb.c.
	147	+ * - Masahiro Adegawa
	148	+ */
	149	+ if (scancode == 0x73)
	150	+ scancode = 0x59;
	151	+ else if (scancode == 0x7d)
	152	+ scancode = 0x7c;
	153	+
	154	+ if (!shift_lock && !shift_key && !ctrl_key) {
	155	+ keychar = plain_map[scancode];
	156	+ } else if ((shift_lock \|\| shift_key) && key_maps[1]) {
	157	+ keychar = key_maps[1][scancode];
	158	+ } else if (ctrl_key && key_maps[4]) {
	159	+ keychar = key_maps[4][scancode];
	160	+ } else {
	161	+ keychar = 0x0020;
	162	+ kdb_printf("Unknown state/scancode (%d)\n", scancode);
	163	+ }
	164	+ keychar &= 0x0fff;
	165	+ if (keychar == '\t')
	166	+ keychar = ' ';
	167	+ switch (KTYP(keychar)) {
	168	+ case KT_LETTER:
	169	+ case KT_LATIN:
	170	+ if (isprint(keychar))
	171	+ break; /* printable characters */
	172	+ /* drop through */
	173	+ case KT_SPEC:
	174	+ if (keychar == K_ENTER)
	175	+ break;
	176	+ /* drop through */
	177	+ default:
	178	+ return -1; /* ignore unprintables */
	179	+ }
	180	+
	181	+ if ((scancode & 0x7f) == 0x1c) {
	182	+ /*
	183	+ * enter key. All done. Absorb the release scancode.
	184	+ */
	185	+ while ((inb(KBD_STATUS_REG) & KBD_STAT_OBF) == 0)
	186	+ ;
	187	+
	188	+ /*
	189	+ * Fetch the scancode
	190	+ */
	191	+ scancode = inb(KBD_DATA_REG);
	192	+ scanstatus = inb(KBD_STATUS_REG);
	193	+
	194	+ while (scanstatus & KBD_STAT_MOUSE_OBF) {
	195	+ scancode = inb(KBD_DATA_REG);
	196	+ scanstatus = inb(KBD_STATUS_REG);
	197	+ }
	198	+
	199	+ if (scancode != 0x9c) {
	200	+ /*
	201	+ * Wasn't an enter-release, why not?
	202	+ */
	203	+ kdb_printf("kdb: expected enter got 0x%x status 0x%x\n",
	204	+ scancode, scanstatus);
	205	+ }
	206	+
	207	+ return 13;
	208	+ }
	209	+
	210	+ return keychar & 0xff;
	211	+}
	212	+EXPORT_SYMBOL_GPL(kdb_get_kbd_char);
...	...	@@ -63,5 +63,12 @@
63	63	help
64	64	KDB frontend for kernel
65	65
	66	+config KDB_KEYBOARD
	67	+ bool "KGDB_KDB: keyboard as input device"
	68	+ depends on VT && KGDB_KDB
	69	+ default n
	70	+ help
	71	+ KDB can use a PS/2 type keyboard for an input device
	72	+
66	73	endif # KGDB