Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2982 insertions, 0 deletions

diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c
new file mode 100644
index 000000000..c27b3dfa1
--- /dev/null
+++ b/kernel/debug/kdb/kdb_main.c
@@ -0,0 +1,2982 @@
+/*
+ * Kernel Debugger Architecture Independent Main Code
+ *
+ * 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) 1999-2004 Silicon Graphics, Inc.  All Rights Reserved.
+ * Copyright (C) 2000 Stephane Eranian <eranian@hpl.hp.com>
+ * Xscale (R) modifications copyright (C) 2003 Intel Corporation.
+ * Copyright (c) 2009 Wind River Systems, Inc.  All Rights Reserved.
+ */
+
+#include <linux/ctype.h>
+#include <linux/types.h>
+#include <linux/string.h>
+#include <linux/kernel.h>
+#include <linux/kmsg_dump.h>
+#include <linux/reboot.h>
+#include <linux/sched.h>
+#include <linux/sched/loadavg.h>
+#include <linux/sched/stat.h>
+#include <linux/sched/debug.h>
+#include <linux/sysrq.h>
+#include <linux/smp.h>
+#include <linux/utsname.h>
+#include <linux/vmalloc.h>
+#include <linux/atomic.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/mm.h>
+#include <linux/init.h>
+#include <linux/kallsyms.h>
+#include <linux/kgdb.h>
+#include <linux/kdb.h>
+#include <linux/notifier.h>
+#include <linux/interrupt.h>
+#include <linux/delay.h>
+#include <linux/nmi.h>
+#include <linux/time.h>
+#include <linux/ptrace.h>
+#include <linux/sysctl.h>
+#include <linux/cpu.h>
+#include <linux/kdebug.h>
+#include <linux/proc_fs.h>
+#include <linux/uaccess.h>
+#include <linux/slab.h>
+#include <linux/security.h>
+#include "kdb_private.h"
+
+#undef	MODULE_PARAM_PREFIX
+#define	MODULE_PARAM_PREFIX "kdb."
+
+static int kdb_cmd_enabled = CONFIG_KDB_DEFAULT_ENABLE;
+module_param_named(cmd_enable, kdb_cmd_enabled, int, 0600);
+
+char kdb_grep_string[KDB_GREP_STRLEN];
+int kdb_grepping_flag;
+EXPORT_SYMBOL(kdb_grepping_flag);
+int kdb_grep_leading;
+int kdb_grep_trailing;
+
+/*
+ * Kernel debugger state flags
+ */
+unsigned int kdb_flags;
+
+/*
+ * kdb_lock protects updates to kdb_initial_cpu.  Used to
+ * single thread processors through the kernel debugger.
+ */
+int kdb_initial_cpu = -1;	/* cpu number that owns kdb */
+int kdb_nextline = 1;
+int kdb_state;			/* General KDB state */
+
+struct task_struct *kdb_current_task;
+struct pt_regs *kdb_current_regs;
+
+const char *kdb_diemsg;
+static int kdb_go_count;
+#ifdef CONFIG_KDB_CONTINUE_CATASTROPHIC
+static unsigned int kdb_continue_catastrophic =
+	CONFIG_KDB_CONTINUE_CATASTROPHIC;
+#else
+static unsigned int kdb_continue_catastrophic;
+#endif
+
+/* kdb_commands describes the available commands. */
+static kdbtab_t *kdb_commands;
+#define KDB_BASE_CMD_MAX 50
+static int kdb_max_commands = KDB_BASE_CMD_MAX;
+static kdbtab_t kdb_base_commands[KDB_BASE_CMD_MAX];
+#define for_each_kdbcmd(cmd, num)					\
+	for ((cmd) = kdb_base_commands, (num) = 0;			\
+	     num < kdb_max_commands;					\
+	     num++, num == KDB_BASE_CMD_MAX ? cmd = kdb_commands : cmd++)
+
+typedef struct _kdbmsg {
+	int	km_diag;	/* kdb diagnostic */
+	char	*km_msg;	/* Corresponding message text */
+} kdbmsg_t;
+
+#define KDBMSG(msgnum, text) \
+	{ KDB_##msgnum, text }
+
+static kdbmsg_t kdbmsgs[] = {
+	KDBMSG(NOTFOUND, "Command Not Found"),
+	KDBMSG(ARGCOUNT, "Improper argument count, see usage."),
+	KDBMSG(BADWIDTH, "Illegal value for BYTESPERWORD use 1, 2, 4 or 8, "
+	       "8 is only allowed on 64 bit systems"),
+	KDBMSG(BADRADIX, "Illegal value for RADIX use 8, 10 or 16"),
+	KDBMSG(NOTENV, "Cannot find environment variable"),
+	KDBMSG(NOENVVALUE, "Environment variable should have value"),
+	KDBMSG(NOTIMP, "Command not implemented"),
+	KDBMSG(ENVFULL, "Environment full"),
+	KDBMSG(ENVBUFFULL, "Environment buffer full"),
+	KDBMSG(TOOMANYBPT, "Too many breakpoints defined"),
+#ifdef CONFIG_CPU_XSCALE
+	KDBMSG(TOOMANYDBREGS, "More breakpoints than ibcr registers defined"),
+#else
+	KDBMSG(TOOMANYDBREGS, "More breakpoints than db registers defined"),
+#endif
+	KDBMSG(DUPBPT, "Duplicate breakpoint address"),
+	KDBMSG(BPTNOTFOUND, "Breakpoint not found"),
+	KDBMSG(BADMODE, "Invalid IDMODE"),
+	KDBMSG(BADINT, "Illegal numeric value"),
+	KDBMSG(INVADDRFMT, "Invalid symbolic address format"),
+	KDBMSG(BADREG, "Invalid register name"),
+	KDBMSG(BADCPUNUM, "Invalid cpu number"),
+	KDBMSG(BADLENGTH, "Invalid length field"),
+	KDBMSG(NOBP, "No Breakpoint exists"),
+	KDBMSG(BADADDR, "Invalid address"),
+	KDBMSG(NOPERM, "Permission denied"),
+};
+#undef KDBMSG
+
+static const int __nkdb_err = ARRAY_SIZE(kdbmsgs);
+
+
+/*
+ * Initial environment.   This is all kept static and local to
+ * this file.   We don't want to rely on the memory allocation
+ * mechanisms in the kernel, so we use a very limited allocate-only
+ * heap for new and altered environment variables.  The entire
+ * environment is limited to a fixed number of entries (add more
+ * to __env[] if required) and a fixed amount of heap (add more to
+ * KDB_ENVBUFSIZE if required).
+ */
+
+static char *__env[] = {
+#if defined(CONFIG_SMP)
+ "PROMPT=[%d]kdb> ",
+#else
+ "PROMPT=kdb> ",
+#endif
+ "MOREPROMPT=more> ",
+ "RADIX=16",
+ "MDCOUNT=8",			/* lines of md output */
+ KDB_PLATFORM_ENV,
+ "DTABCOUNT=30",
+ "NOSECT=1",
+ (char *)0,
+ (char *)0,
+ (char *)0,
+ (char *)0,
+ (char *)0,
+ (char *)0,
+ (char *)0,
+ (char *)0,
+ (char *)0,
+ (char *)0,
+ (char *)0,
+ (char *)0,
+ (char *)0,
+ (char *)0,
+ (char *)0,
+ (char *)0,
+ (char *)0,
+ (char *)0,
+ (char *)0,
+ (char *)0,
+ (char *)0,
+ (char *)0,
+ (char *)0,
+ (char *)0,
+};
+
+static const int __nenv = ARRAY_SIZE(__env);
+
+struct task_struct *kdb_curr_task(int cpu)
+{
+	struct task_struct *p = curr_task(cpu);
+#ifdef	_TIF_MCA_INIT
+	if ((task_thread_info(p)->flags & _TIF_MCA_INIT) && KDB_TSK(cpu))
+		p = krp->p;
+#endif
+	return p;
+}
+
+/*
+ * Update the permissions flags (kdb_cmd_enabled) to match the
+ * current lockdown state.
+ *
+ * Within this function the calls to security_locked_down() are "lazy". We
+ * avoid calling them if the current value of kdb_cmd_enabled already excludes
+ * flags that might be subject to lockdown. Additionally we deliberately check
+ * the lockdown flags independently (even though read lockdown implies write
+ * lockdown) since that results in both simpler code and clearer messages to
+ * the user on first-time debugger entry.
+ *
+ * The permission masks during a read+write lockdown permits the following
+ * flags: INSPECT, SIGNAL, REBOOT (and ALWAYS_SAFE).
+ *
+ * The INSPECT commands are not blocked during lockdown because they are
+ * not arbitrary memory reads. INSPECT covers the backtrace family (sometimes
+ * forcing them to have no arguments) and lsmod. These commands do expose
+ * some kernel state but do not allow the developer seated at the console to
+ * choose what state is reported. SIGNAL and REBOOT should not be controversial,
+ * given these are allowed for root during lockdown already.
+ */
+static void kdb_check_for_lockdown(void)
+{
+	const int write_flags = KDB_ENABLE_MEM_WRITE |
+				KDB_ENABLE_REG_WRITE |
+				KDB_ENABLE_FLOW_CTRL;
+	const int read_flags = KDB_ENABLE_MEM_READ |
+			       KDB_ENABLE_REG_READ;
+
+	bool need_to_lockdown_write = false;
+	bool need_to_lockdown_read = false;
+
+	if (kdb_cmd_enabled & (KDB_ENABLE_ALL | write_flags))
+		need_to_lockdown_write =
+			security_locked_down(LOCKDOWN_DBG_WRITE_KERNEL);
+
+	if (kdb_cmd_enabled & (KDB_ENABLE_ALL | read_flags))
+		need_to_lockdown_read =
+			security_locked_down(LOCKDOWN_DBG_READ_KERNEL);
+
+	/* De-compose KDB_ENABLE_ALL if required */
+	if (need_to_lockdown_write || need_to_lockdown_read)
+		if (kdb_cmd_enabled & KDB_ENABLE_ALL)
+			kdb_cmd_enabled = KDB_ENABLE_MASK & ~KDB_ENABLE_ALL;
+
+	if (need_to_lockdown_write)
+		kdb_cmd_enabled &= ~write_flags;
+
+	if (need_to_lockdown_read)
+		kdb_cmd_enabled &= ~read_flags;
+}
+
+/*
+ * Check whether the flags of the current command, the permissions of the kdb
+ * console and the lockdown state allow a command to be run.
+ */
+static bool kdb_check_flags(kdb_cmdflags_t flags, int permissions,
+				   bool no_args)
+{
+	/* permissions comes from userspace so needs massaging slightly */
+	permissions &= KDB_ENABLE_MASK;
+	permissions |= KDB_ENABLE_ALWAYS_SAFE;
+
+	/* some commands change group when launched with no arguments */
+	if (no_args)
+		permissions |= permissions << KDB_ENABLE_NO_ARGS_SHIFT;
+
+	flags |= KDB_ENABLE_ALL;
+
+	return permissions & flags;
+}
+
+/*
+ * kdbgetenv - This function will return the character string value of
+ *	an environment variable.
+ * Parameters:
+ *	match	A character string representing an environment variable.
+ * Returns:
+ *	NULL	No environment variable matches 'match'
+ *	char*	Pointer to string value of environment variable.
+ */
+char *kdbgetenv(const char *match)
+{
+	char **ep = __env;
+	int matchlen = strlen(match);
+	int i;
+
+	for (i = 0; i < __nenv; i++) {
+		char *e = *ep++;
+
+		if (!e)
+			continue;
+
+		if ((strncmp(match, e, matchlen) == 0)
+		 && ((e[matchlen] == '\0')
+		   || (e[matchlen] == '='))) {
+			char *cp = strchr(e, '=');
+			return cp ? ++cp : "";
+		}
+	}
+	return NULL;
+}
+
+/*
+ * kdballocenv - This function is used to allocate bytes for
+ *	environment entries.
+ * Parameters:
+ *	match	A character string representing a numeric value
+ * Outputs:
+ *	*value  the unsigned long representation of the env variable 'match'
+ * Returns:
+ *	Zero on success, a kdb diagnostic on failure.
+ * Remarks:
+ *	We use a static environment buffer (envbuffer) to hold the values
+ *	of dynamically generated environment variables (see kdb_set).  Buffer
+ *	space once allocated is never free'd, so over time, the amount of space
+ *	(currently 512 bytes) will be exhausted if env variables are changed
+ *	frequently.
+ */
+static char *kdballocenv(size_t bytes)
+{
+#define	KDB_ENVBUFSIZE	512
+	static char envbuffer[KDB_ENVBUFSIZE];
+	static int envbufsize;
+	char *ep = NULL;
+
+	if ((KDB_ENVBUFSIZE - envbufsize) >= bytes) {
+		ep = &envbuffer[envbufsize];
+		envbufsize += bytes;
+	}
+	return ep;
+}
+
+/*
+ * kdbgetulenv - This function will return the value of an unsigned
+ *	long-valued environment variable.
+ * Parameters:
+ *	match	A character string representing a numeric value
+ * Outputs:
+ *	*value  the unsigned long represntation of the env variable 'match'
+ * Returns:
+ *	Zero on success, a kdb diagnostic on failure.
+ */
+static int kdbgetulenv(const char *match, unsigned long *value)
+{
+	char *ep;
+
+	ep = kdbgetenv(match);
+	if (!ep)
+		return KDB_NOTENV;
+	if (strlen(ep) == 0)
+		return KDB_NOENVVALUE;
+
+	*value = simple_strtoul(ep, NULL, 0);
+
+	return 0;
+}
+
+/*
+ * kdbgetintenv - This function will return the value of an
+ *	integer-valued environment variable.
+ * Parameters:
+ *	match	A character string representing an integer-valued env variable
+ * Outputs:
+ *	*value  the integer representation of the environment variable 'match'
+ * Returns:
+ *	Zero on success, a kdb diagnostic on failure.
+ */
+int kdbgetintenv(const char *match, int *value)
+{
+	unsigned long val;
+	int diag;
+
+	diag = kdbgetulenv(match, &val);
+	if (!diag)
+		*value = (int) val;
+	return diag;
+}
+
+/*
+ * kdbgetularg - This function will convert a numeric string into an
+ *	unsigned long value.
+ * Parameters:
+ *	arg	A character string representing a numeric value
+ * Outputs:
+ *	*value  the unsigned long represntation of arg.
+ * Returns:
+ *	Zero on success, a kdb diagnostic on failure.
+ */
+int kdbgetularg(const char *arg, unsigned long *value)
+{
+	char *endp;
+	unsigned long val;
+
+	val = simple_strtoul(arg, &endp, 0);
+
+	if (endp == arg) {
+		/*
+		 * Also try base 16, for us folks too lazy to type the
+		 * leading 0x...
+		 */
+		val = simple_strtoul(arg, &endp, 16);
+		if (endp == arg)
+			return KDB_BADINT;
+	}
+
+	*value = val;
+
+	return 0;
+}
+
+int kdbgetu64arg(const char *arg, u64 *value)
+{
+	char *endp;
+	u64 val;
+
+	val = simple_strtoull(arg, &endp, 0);
+
+	if (endp == arg) {
+
+		val = simple_strtoull(arg, &endp, 16);
+		if (endp == arg)
+			return KDB_BADINT;
+	}
+
+	*value = val;
+
+	return 0;
+}
+
+/*
+ * kdb_set - This function implements the 'set' command.  Alter an
+ *	existing environment variable or create a new one.
+ */
+int kdb_set(int argc, const char **argv)
+{
+	int i;
+	char *ep;
+	size_t varlen, vallen;
+
+	/*
+	 * we can be invoked two ways:
+	 *   set var=value    argv[1]="var", argv[2]="value"
+	 *   set var = value  argv[1]="var", argv[2]="=", argv[3]="value"
+	 * - if the latter, shift 'em down.
+	 */
+	if (argc == 3) {
+		argv[2] = argv[3];
+		argc--;
+	}
+
+	if (argc != 2)
+		return KDB_ARGCOUNT;
+
+	/*
+	 * Censor sensitive variables
+	 */
+	if (strcmp(argv[1], "PROMPT") == 0 &&
+	    !kdb_check_flags(KDB_ENABLE_MEM_READ, kdb_cmd_enabled, false))
+		return KDB_NOPERM;
+
+	/*
+	 * Check for internal variables
+	 */
+	if (strcmp(argv[1], "KDBDEBUG") == 0) {
+		unsigned int debugflags;
+		char *cp;
+
+		debugflags = simple_strtoul(argv[2], &cp, 0);
+		if (cp == argv[2] || debugflags & ~KDB_DEBUG_FLAG_MASK) {
+			kdb_printf("kdb: illegal debug flags '%s'\n",
+				    argv[2]);
+			return 0;
+		}
+		kdb_flags = (kdb_flags & ~KDB_DEBUG(MASK))
+			| (debugflags << KDB_DEBUG_FLAG_SHIFT);
+
+		return 0;
+	}
+
+	/*
+	 * Tokenizer squashed the '=' sign.  argv[1] is variable
+	 * name, argv[2] = value.
+	 */
+	varlen = strlen(argv[1]);
+	vallen = strlen(argv[2]);
+	ep = kdballocenv(varlen + vallen + 2);
+	if (ep == (char *)0)
+		return KDB_ENVBUFFULL;
+
+	sprintf(ep, "%s=%s", argv[1], argv[2]);
+
+	ep[varlen+vallen+1] = '\0';
+
+	for (i = 0; i < __nenv; i++) {
+		if (__env[i]
+		 && ((strncmp(__env[i], argv[1], varlen) == 0)
+		   && ((__env[i][varlen] == '\0')
+		    || (__env[i][varlen] == '=')))) {
+			__env[i] = ep;
+			return 0;
+		}
+	}
+
+	/*
+	 * Wasn't existing variable.  Fit into slot.
+	 */
+	for (i = 0; i < __nenv-1; i++) {
+		if (__env[i] == (char *)0) {
+			__env[i] = ep;
+			return 0;
+		}
+	}
+
+	return KDB_ENVFULL;
+}
+
+static int kdb_check_regs(void)
+{
+	if (!kdb_current_regs) {
+		kdb_printf("No current kdb registers."
+			   "  You may need to select another task\n");
+		return KDB_BADREG;
+	}
+	return 0;
+}
+
+/*
+ * kdbgetaddrarg - This function is responsible for parsing an
+ *	address-expression and returning the value of the expression,
+ *	symbol name, and offset to the caller.
+ *
+ *	The argument may consist of a numeric value (decimal or
+ *	hexidecimal), a symbol name, a register name (preceded by the
+ *	percent sign), an environment variable with a numeric value
+ *	(preceded by a dollar sign) or a simple arithmetic expression
+ *	consisting of a symbol name, +/-, and a numeric constant value
+ *	(offset).
+ * Parameters:
+ *	argc	- count of arguments in argv
+ *	argv	- argument vector
+ *	*nextarg - index to next unparsed argument in argv[]
+ *	regs	- Register state at time of KDB entry
+ * Outputs:
+ *	*value	- receives the value of the address-expression
+ *	*offset - receives the offset specified, if any
+ *	*name   - receives the symbol name, if any
+ *	*nextarg - index to next unparsed argument in argv[]
+ * Returns:
+ *	zero is returned on success, a kdb diagnostic code is
+ *      returned on error.
+ */
+int kdbgetaddrarg(int argc, const char **argv, int *nextarg,
+		  unsigned long *value,  long *offset,
+		  char **name)
+{
+	unsigned long addr;
+	unsigned long off = 0;
+	int positive;
+	int diag;
+	int found = 0;
+	char *symname;
+	char symbol = '\0';
+	char *cp;
+	kdb_symtab_t symtab;
+
+	/*
+	 * If the enable flags prohibit both arbitrary memory access
+	 * and flow control then there are no reasonable grounds to
+	 * provide symbol lookup.
+	 */
+	if (!kdb_check_flags(KDB_ENABLE_MEM_READ | KDB_ENABLE_FLOW_CTRL,
+			     kdb_cmd_enabled, false))
+		return KDB_NOPERM;
+
+	/*
+	 * Process arguments which follow the following syntax:
+	 *
+	 *  symbol | numeric-address [+/- numeric-offset]
+	 *  %register
+	 *  $environment-variable
+	 */
+
+	if (*nextarg > argc)
+		return KDB_ARGCOUNT;
+
+	symname = (char *)argv[*nextarg];
+
+	/*
+	 * If there is no whitespace between the symbol
+	 * or address and the '+' or '-' symbols, we
+	 * remember the character and replace it with a
+	 * null so the symbol/value can be properly parsed
+	 */
+	cp = strpbrk(symname, "+-");
+	if (cp != NULL) {
+		symbol = *cp;
+		*cp++ = '\0';
+	}
+
+	if (symname[0] == '$') {
+		diag = kdbgetulenv(&symname[1], &addr);
+		if (diag)
+			return diag;
+	} else if (symname[0] == '%') {
+		diag = kdb_check_regs();
+		if (diag)
+			return diag;
+		/* Implement register values with % at a later time as it is
+		 * arch optional.
+		 */
+		return KDB_NOTIMP;
+	} else {
+		found = kdbgetsymval(symname, &symtab);
+		if (found) {
+			addr = symtab.sym_start;
+		} else {
+			diag = kdbgetularg(argv[*nextarg], &addr);
+			if (diag)
+				return diag;
+		}
+	}
+
+	if (!found)
+		found = kdbnearsym(addr, &symtab);
+
+	(*nextarg)++;
+
+	if (name)
+		*name = symname;
+	if (value)
+		*value = addr;
+	if (offset && name && *name)
+		*offset = addr - symtab.sym_start;
+
+	if ((*nextarg > argc)
+	 && (symbol == '\0'))
+		return 0;
+
+	/*
+	 * check for +/- and offset
+	 */
+
+	if (symbol == '\0') {
+		if ((argv[*nextarg][0] != '+')
+		 && (argv[*nextarg][0] != '-')) {
+			/*
+			 * Not our argument.  Return.
+			 */
+			return 0;
+		} else {
+			positive = (argv[*nextarg][0] == '+');
+			(*nextarg)++;
+		}
+	} else
+		positive = (symbol == '+');
+
+	/*
+	 * Now there must be an offset!
+	 */
+	if ((*nextarg > argc)
+	 && (symbol == '\0')) {
+		return KDB_INVADDRFMT;
+	}
+
+	if (!symbol) {
+		cp = (char *)argv[*nextarg];
+		(*nextarg)++;
+	}
+
+	diag = kdbgetularg(cp, &off);
+	if (diag)
+		return diag;
+
+	if (!positive)
+		off = -off;
+
+	if (offset)
+		*offset += off;
+
+	if (value)
+		*value += off;
+
+	return 0;
+}
+
+static void kdb_cmderror(int diag)
+{
+	int i;
+
+	if (diag >= 0) {
+		kdb_printf("no error detected (diagnostic is %d)\n", diag);
+		return;
+	}
+
+	for (i = 0; i < __nkdb_err; i++) {
+		if (kdbmsgs[i].km_diag == diag) {
+			kdb_printf("diag: %d: %s\n", diag, kdbmsgs[i].km_msg);
+			return;
+		}
+	}
+
+	kdb_printf("Unknown diag %d\n", -diag);
+}
+
+/*
+ * kdb_defcmd, kdb_defcmd2 - This function implements the 'defcmd'
+ *	command which defines one command as a set of other commands,
+ *	terminated by endefcmd.  kdb_defcmd processes the initial
+ *	'defcmd' command, kdb_defcmd2 is invoked from kdb_parse for
+ *	the following commands until 'endefcmd'.
+ * Inputs:
+ *	argc	argument count
+ *	argv	argument vector
+ * Returns:
+ *	zero for success, a kdb diagnostic if error
+ */
+struct defcmd_set {
+	int count;
+	bool usable;
+	char *name;
+	char *usage;
+	char *help;
+	char **command;
+};
+static struct defcmd_set *defcmd_set;
+static int defcmd_set_count;
+static bool defcmd_in_progress;
+
+/* Forward references */
+static int kdb_exec_defcmd(int argc, const char **argv);
+
+static int kdb_defcmd2(const char *cmdstr, const char *argv0)
+{
+	struct defcmd_set *s = defcmd_set + defcmd_set_count - 1;
+	char **save_command = s->command;
+	if (strcmp(argv0, "endefcmd") == 0) {
+		defcmd_in_progress = false;
+		if (!s->count)
+			s->usable = false;
+		if (s->usable)
+			/* macros are always safe because when executed each
+			 * internal command re-enters kdb_parse() and is
+			 * safety checked individually.
+			 */
+			kdb_register_flags(s->name, kdb_exec_defcmd, s->usage,
+					   s->help, 0,
+					   KDB_ENABLE_ALWAYS_SAFE);
+		return 0;
+	}
+	if (!s->usable)
+		return KDB_NOTIMP;
+	s->command = kcalloc(s->count + 1, sizeof(*(s->command)), GFP_KDB);
+	if (!s->command) {
+		kdb_printf("Could not allocate new kdb_defcmd table for %s\n",
+			   cmdstr);
+		s->usable = false;
+		return KDB_NOTIMP;
+	}
+	memcpy(s->command, save_command, s->count * sizeof(*(s->command)));
+	s->command[s->count++] = kdb_strdup(cmdstr, GFP_KDB);
+	kfree(save_command);
+	return 0;
+}
+
+static int kdb_defcmd(int argc, const char **argv)
+{
+	struct defcmd_set *save_defcmd_set = defcmd_set, *s;
+	if (defcmd_in_progress) {
+		kdb_printf("kdb: nested defcmd detected, assuming missing "
+			   "endefcmd\n");
+		kdb_defcmd2("endefcmd", "endefcmd");
+	}
+	if (argc == 0) {
+		int i;
+		for (s = defcmd_set; s < defcmd_set + defcmd_set_count; ++s) {
+			kdb_printf("defcmd %s \"%s\" \"%s\"\n", s->name,
+				   s->usage, s->help);
+			for (i = 0; i < s->count; ++i)
+				kdb_printf("%s", s->command[i]);
+			kdb_printf("endefcmd\n");
+		}
+		return 0;
+	}
+	if (argc != 3)
+		return KDB_ARGCOUNT;
+	if (in_dbg_master()) {
+		kdb_printf("Command only available during kdb_init()\n");
+		return KDB_NOTIMP;
+	}
+	defcmd_set = kmalloc_array(defcmd_set_count + 1, sizeof(*defcmd_set),
+				   GFP_KDB);
+	if (!defcmd_set)
+		goto fail_defcmd;
+	memcpy(defcmd_set, save_defcmd_set,
+	       defcmd_set_count * sizeof(*defcmd_set));
+	s = defcmd_set + defcmd_set_count;
+	memset(s, 0, sizeof(*s));
+	s->usable = true;
+	s->name = kdb_strdup(argv[1], GFP_KDB);
+	if (!s->name)
+		goto fail_name;
+	s->usage = kdb_strdup(argv[2], GFP_KDB);
+	if (!s->usage)
+		goto fail_usage;
+	s->help = kdb_strdup(argv[3], GFP_KDB);
+	if (!s->help)
+		goto fail_help;
+	if (s->usage[0] == '"') {
+		strcpy(s->usage, argv[2]+1);
+		s->usage[strlen(s->usage)-1] = '\0';
+	}
+	if (s->help[0] == '"') {
+		strcpy(s->help, argv[3]+1);
+		s->help[strlen(s->help)-1] = '\0';
+	}
+	++defcmd_set_count;
+	defcmd_in_progress = true;
+	kfree(save_defcmd_set);
+	return 0;
+fail_help:
+	kfree(s->usage);
+fail_usage:
+	kfree(s->name);
+fail_name:
+	kfree(defcmd_set);
+fail_defcmd:
+	kdb_printf("Could not allocate new defcmd_set entry for %s\n", argv[1]);
+	defcmd_set = save_defcmd_set;
+	return KDB_NOTIMP;
+}
+
+/*
+ * kdb_exec_defcmd - Execute the set of commands associated with this
+ *	defcmd name.
+ * Inputs:
+ *	argc	argument count
+ *	argv	argument vector
+ * Returns:
+ *	zero for success, a kdb diagnostic if error
+ */
+static int kdb_exec_defcmd(int argc, const char **argv)
+{
+	int i, ret;
+	struct defcmd_set *s;
+	if (argc != 0)
+		return KDB_ARGCOUNT;
+	for (s = defcmd_set, i = 0; i < defcmd_set_count; ++i, ++s) {
+		if (strcmp(s->name, argv[0]) == 0)
+			break;
+	}
+	if (i == defcmd_set_count) {
+		kdb_printf("kdb_exec_defcmd: could not find commands for %s\n",
+			   argv[0]);
+		return KDB_NOTIMP;
+	}
+	for (i = 0; i < s->count; ++i) {
+		/* Recursive use of kdb_parse, do not use argv after
+		 * this point */
+		argv = NULL;
+		kdb_printf("[%s]kdb> %s\n", s->name, s->command[i]);
+		ret = kdb_parse(s->command[i]);
+		if (ret)
+			return ret;
+	}
+	return 0;
+}
+
+/* Command history */
+#define KDB_CMD_HISTORY_COUNT	32
+#define CMD_BUFLEN		200	/* kdb_printf: max printline
+					 * size == 256 */
+static unsigned int cmd_head, cmd_tail;
+static unsigned int cmdptr;
+static char cmd_hist[KDB_CMD_HISTORY_COUNT][CMD_BUFLEN];
+static char cmd_cur[CMD_BUFLEN];
+
+/*
+ * The "str" argument may point to something like  | grep xyz
+ */
+static void parse_grep(const char *str)
+{
+	int	len;
+	char	*cp = (char *)str, *cp2;
+
+	/* sanity check: we should have been called with the \ first */
+	if (*cp != '|')
+		return;
+	cp++;
+	while (isspace(*cp))
+		cp++;
+	if (!str_has_prefix(cp, "grep ")) {
+		kdb_printf("invalid 'pipe', see grephelp\n");
+		return;
+	}
+	cp += 5;
+	while (isspace(*cp))
+		cp++;
+	cp2 = strchr(cp, '\n');
+	if (cp2)
+		*cp2 = '\0'; /* remove the trailing newline */
+	len = strlen(cp);
+	if (len == 0) {
+		kdb_printf("invalid 'pipe', see grephelp\n");
+		return;
+	}
+	/* now cp points to a nonzero length search string */
+	if (*cp == '"') {
+		/* allow it be "x y z" by removing the "'s - there must
+		   be two of them */
+		cp++;
+		cp2 = strchr(cp, '"');
+		if (!cp2) {
+			kdb_printf("invalid quoted string, see grephelp\n");
+			return;
+		}
+		*cp2 = '\0'; /* end the string where the 2nd " was */
+	}
+	kdb_grep_leading = 0;
+	if (*cp == '^') {
+		kdb_grep_leading = 1;
+		cp++;
+	}
+	len = strlen(cp);
+	kdb_grep_trailing = 0;
+	if (*(cp+len-1) == '$') {
+		kdb_grep_trailing = 1;
+		*(cp+len-1) = '\0';
+	}
+	len = strlen(cp);
+	if (!len)
+		return;
+	if (len >= KDB_GREP_STRLEN) {
+		kdb_printf("search string too long\n");
+		return;
+	}
+	strcpy(kdb_grep_string, cp);
+	kdb_grepping_flag++;
+	return;
+}
+
+/*
+ * kdb_parse - Parse the command line, search the command table for a
+ *	matching command and invoke the command function.  This
+ *	function may be called recursively, if it is, the second call
+ *	will overwrite argv and cbuf.  It is the caller's
+ *	responsibility to save their argv if they recursively call
+ *	kdb_parse().
+ * Parameters:
+ *      cmdstr	The input command line to be parsed.
+ *	regs	The registers at the time kdb was entered.
+ * Returns:
+ *	Zero for success, a kdb diagnostic if failure.
+ * Remarks:
+ *	Limited to 20 tokens.
+ *
+ *	Real rudimentary tokenization. Basically only whitespace
+ *	is considered a token delimeter (but special consideration
+ *	is taken of the '=' sign as used by the 'set' command).
+ *
+ *	The algorithm used to tokenize the input string relies on
+ *	there being at least one whitespace (or otherwise useless)
+ *	character between tokens as the character immediately following
+ *	the token is altered in-place to a null-byte to terminate the
+ *	token string.
+ */
+
+#define MAXARGC	20
+
+int kdb_parse(const char *cmdstr)
+{
+	static char *argv[MAXARGC];
+	static int argc;
+	static char cbuf[CMD_BUFLEN+2];
+	char *cp;
+	char *cpp, quoted;
+	kdbtab_t *tp;
+	int i, escaped, ignore_errors = 0, check_grep = 0;
+
+	/*
+	 * First tokenize the command string.
+	 */
+	cp = (char *)cmdstr;
+
+	if (KDB_FLAG(CMD_INTERRUPT)) {
+		/* Previous command was interrupted, newline must not
+		 * repeat the command */
+		KDB_FLAG_CLEAR(CMD_INTERRUPT);
+		KDB_STATE_SET(PAGER);
+		argc = 0;	/* no repeat */
+	}
+
+	if (*cp != '\n' && *cp != '\0') {
+		argc = 0;
+		cpp = cbuf;
+		while (*cp) {
+			/* skip whitespace */
+			while (isspace(*cp))
+				cp++;
+			if ((*cp == '\0') || (*cp == '\n') ||
+			    (*cp == '#' && !defcmd_in_progress))
+				break;
+			/* special case: check for | grep pattern */
+			if (*cp == '|') {
+				check_grep++;
+				break;
+			}
+			if (cpp >= cbuf + CMD_BUFLEN) {
+				kdb_printf("kdb_parse: command buffer "
+					   "overflow, command ignored\n%s\n",
+					   cmdstr);
+				return KDB_NOTFOUND;
+			}
+			if (argc >= MAXARGC - 1) {
+				kdb_printf("kdb_parse: too many arguments, "
+					   "command ignored\n%s\n", cmdstr);
+				return KDB_NOTFOUND;
+			}
+			argv[argc++] = cpp;
+			escaped = 0;
+			quoted = '\0';
+			/* Copy to next unquoted and unescaped
+			 * whitespace or '=' */
+			while (*cp && *cp != '\n' &&
+			       (escaped || quoted || !isspace(*cp))) {
+				if (cpp >= cbuf + CMD_BUFLEN)
+					break;
+				if (escaped) {
+					escaped = 0;
+					*cpp++ = *cp++;
+					continue;
+				}
+				if (*cp == '\\') {
+					escaped = 1;
+					++cp;
+					continue;
+				}
+				if (*cp == quoted)
+					quoted = '\0';
+				else if (*cp == '\'' || *cp == '"')
+					quoted = *cp;
+				*cpp = *cp++;
+				if (*cpp == '=' && !quoted)
+					break;
+				++cpp;
+			}
+			*cpp++ = '\0';	/* Squash a ws or '=' character */
+		}
+	}
+	if (!argc)
+		return 0;
+	if (check_grep)
+		parse_grep(cp);
+	if (defcmd_in_progress) {
+		int result = kdb_defcmd2(cmdstr, argv[0]);
+		if (!defcmd_in_progress) {
+			argc = 0;	/* avoid repeat on endefcmd */
+			*(argv[0]) = '\0';
+		}
+		return result;
+	}
+	if (argv[0][0] == '-' && argv[0][1] &&
+	    (argv[0][1] < '0' || argv[0][1] > '9')) {
+		ignore_errors = 1;
+		++argv[0];
+	}
+
+	for_each_kdbcmd(tp, i) {
+		if (tp->cmd_name) {
+			/*
+			 * If this command is allowed to be abbreviated,
+			 * check to see if this is it.
+			 */
+
+			if (tp->cmd_minlen
+			 && (strlen(argv[0]) <= tp->cmd_minlen)) {
+				if (strncmp(argv[0],
+					    tp->cmd_name,
+					    tp->cmd_minlen) == 0) {
+					break;
+				}
+			}
+
+			if (strcmp(argv[0], tp->cmd_name) == 0)
+				break;
+		}
+	}
+
+	/*
+	 * If we don't find a command by this name, see if the first
+	 * few characters of this match any of the known commands.
+	 * e.g., md1c20 should match md.
+	 */
+	if (i == kdb_max_commands) {
+		for_each_kdbcmd(tp, i) {
+			if (tp->cmd_name) {
+				if (strncmp(argv[0],
+					    tp->cmd_name,
+					    strlen(tp->cmd_name)) == 0) {
+					break;
+				}
+			}
+		}
+	}
+
+	if (i < kdb_max_commands) {
+		int result;
+
+		if (!kdb_check_flags(tp->cmd_flags, kdb_cmd_enabled, argc <= 1))
+			return KDB_NOPERM;
+
+		KDB_STATE_SET(CMD);
+		result = (*tp->cmd_func)(argc-1, (const char **)argv);
+		if (result && ignore_errors && result > KDB_CMD_GO)
+			result = 0;
+		KDB_STATE_CLEAR(CMD);
+
+		if (tp->cmd_flags & KDB_REPEAT_WITH_ARGS)
+			return result;
+
+		argc = tp->cmd_flags & KDB_REPEAT_NO_ARGS ? 1 : 0;
+		if (argv[argc])
+			*(argv[argc]) = '\0';
+		return result;
+	}
+
+	/*
+	 * If the input with which we were presented does not
+	 * map to an existing command, attempt to parse it as an
+	 * address argument and display the result.   Useful for
+	 * obtaining the address of a variable, or the nearest symbol
+	 * to an address contained in a register.
+	 */
+	{
+		unsigned long value;
+		char *name = NULL;
+		long offset;
+		int nextarg = 0;
+
+		if (kdbgetaddrarg(0, (const char **)argv, &nextarg,
+				  &value, &offset, &name)) {
+			return KDB_NOTFOUND;
+		}
+
+		kdb_printf("%s = ", argv[0]);
+		kdb_symbol_print(value, NULL, KDB_SP_DEFAULT);
+		kdb_printf("\n");
+		return 0;
+	}
+}
+
+
+static int handle_ctrl_cmd(char *cmd)
+{
+#define CTRL_P	16
+#define CTRL_N	14
+
+	/* initial situation */
+	if (cmd_head == cmd_tail)
+		return 0;
+	switch (*cmd) {
+	case CTRL_P:
+		if (cmdptr != cmd_tail)
+			cmdptr = (cmdptr + KDB_CMD_HISTORY_COUNT - 1) %
+				 KDB_CMD_HISTORY_COUNT;
+		strscpy(cmd_cur, cmd_hist[cmdptr], CMD_BUFLEN);
+		return 1;
+	case CTRL_N:
+		if (cmdptr != cmd_head)
+			cmdptr = (cmdptr+1) % KDB_CMD_HISTORY_COUNT;
+		strscpy(cmd_cur, cmd_hist[cmdptr], CMD_BUFLEN);
+		return 1;
+	}
+	return 0;
+}
+
+/*
+ * kdb_reboot - This function implements the 'reboot' command.  Reboot
+ *	the system immediately, or loop for ever on failure.
+ */
+static int kdb_reboot(int argc, const char **argv)
+{
+	emergency_restart();
+	kdb_printf("Hmm, kdb_reboot did not reboot, spinning here\n");
+	while (1)
+		cpu_relax();
+	/* NOTREACHED */
+	return 0;
+}
+
+static void kdb_dumpregs(struct pt_regs *regs)
+{
+	int old_lvl = console_loglevel;
+	console_loglevel = CONSOLE_LOGLEVEL_MOTORMOUTH;
+	kdb_trap_printk++;
+	show_regs(regs);
+	kdb_trap_printk--;
+	kdb_printf("\n");
+	console_loglevel = old_lvl;
+}
+
+static void kdb_set_current_task(struct task_struct *p)
+{
+	kdb_current_task = p;
+
+	if (kdb_task_has_cpu(p)) {
+		kdb_current_regs = KDB_TSKREGS(kdb_process_cpu(p));
+		return;
+	}
+	kdb_current_regs = NULL;
+}
+
+static void drop_newline(char *buf)
+{
+	size_t len = strlen(buf);
+
+	if (len == 0)
+		return;
+	if (*(buf + len - 1) == '\n')
+		*(buf + len - 1) = '\0';
+}
+
+/*
+ * kdb_local - The main code for kdb.  This routine is invoked on a
+ *	specific processor, it is not global.  The main kdb() routine
+ *	ensures that only one processor at a time is in this routine.
+ *	This code is called with the real reason code on the first
+ *	entry to a kdb session, thereafter it is called with reason
+ *	SWITCH, even if the user goes back to the original cpu.
+ * Inputs:
+ *	reason		The reason KDB was invoked
+ *	error		The hardware-defined error code
+ *	regs		The exception frame at time of fault/breakpoint.
+ *	db_result	Result code from the break or debug point.
+ * Returns:
+ *	0	KDB was invoked for an event which it wasn't responsible
+ *	1	KDB handled the event for which it was invoked.
+ *	KDB_CMD_GO	User typed 'go'.
+ *	KDB_CMD_CPU	User switched to another cpu.
+ *	KDB_CMD_SS	Single step.
+ */
+static int kdb_local(kdb_reason_t reason, int error, struct pt_regs *regs,
+		     kdb_dbtrap_t db_result)
+{
+	char *cmdbuf;
+	int diag;
+	struct task_struct *kdb_current =
+		kdb_curr_task(raw_smp_processor_id());
+
+	KDB_DEBUG_STATE("kdb_local 1", reason);
+
+	kdb_check_for_lockdown();
+
+	kdb_go_count = 0;
+	if (reason == KDB_REASON_DEBUG) {
+		/* special case below */
+	} else {
+		kdb_printf("\nEntering kdb (current=0x%px, pid %d) ",
+			   kdb_current, kdb_current ? kdb_current->pid : 0);
+#if defined(CONFIG_SMP)
+		kdb_printf("on processor %d ", raw_smp_processor_id());
+#endif
+	}
+
+	switch (reason) {
+	case KDB_REASON_DEBUG:
+	{
+		/*
+		 * If re-entering kdb after a single step
+		 * command, don't print the message.
+		 */
+		switch (db_result) {
+		case KDB_DB_BPT:
+			kdb_printf("\nEntering kdb (0x%px, pid %d) ",
+				   kdb_current, kdb_current->pid);
+#if defined(CONFIG_SMP)
+			kdb_printf("on processor %d ", raw_smp_processor_id());
+#endif
+			kdb_printf("due to Debug @ " kdb_machreg_fmt "\n",
+				   instruction_pointer(regs));
+			break;
+		case KDB_DB_SS:
+			break;
+		case KDB_DB_SSBPT:
+			KDB_DEBUG_STATE("kdb_local 4", reason);
+			return 1;	/* kdba_db_trap did the work */
+		default:
+			kdb_printf("kdb: Bad result from kdba_db_trap: %d\n",
+				   db_result);
+			break;
+		}
+
+	}
+		break;
+	case KDB_REASON_ENTER:
+		if (KDB_STATE(KEYBOARD))
+			kdb_printf("due to Keyboard Entry\n");
+		else
+			kdb_printf("due to KDB_ENTER()\n");
+		break;
+	case KDB_REASON_KEYBOARD:
+		KDB_STATE_SET(KEYBOARD);
+		kdb_printf("due to Keyboard Entry\n");
+		break;
+	case KDB_REASON_ENTER_SLAVE:
+		/* drop through, slaves only get released via cpu switch */
+	case KDB_REASON_SWITCH:
+		kdb_printf("due to cpu switch\n");
+		break;
+	case KDB_REASON_OOPS:
+		kdb_printf("Oops: %s\n", kdb_diemsg);
+		kdb_printf("due to oops @ " kdb_machreg_fmt "\n",
+			   instruction_pointer(regs));
+		kdb_dumpregs(regs);
+		break;
+	case KDB_REASON_SYSTEM_NMI:
+		kdb_printf("due to System NonMaskable Interrupt\n");
+		break;
+	case KDB_REASON_NMI:
+		kdb_printf("due to NonMaskable Interrupt @ "
+			   kdb_machreg_fmt "\n",
+			   instruction_pointer(regs));
+		break;
+	case KDB_REASON_SSTEP:
+	case KDB_REASON_BREAK:
+		kdb_printf("due to %s @ " kdb_machreg_fmt "\n",
+			   reason == KDB_REASON_BREAK ?
+			   "Breakpoint" : "SS trap", instruction_pointer(regs));
+		/*
+		 * Determine if this breakpoint is one that we
+		 * are interested in.
+		 */
+		if (db_result != KDB_DB_BPT) {
+			kdb_printf("kdb: error return from kdba_bp_trap: %d\n",
+				   db_result);
+			KDB_DEBUG_STATE("kdb_local 6", reason);
+			return 0;	/* Not for us, dismiss it */
+		}
+		break;
+	case KDB_REASON_RECURSE:
+		kdb_printf("due to Recursion @ " kdb_machreg_fmt "\n",
+			   instruction_pointer(regs));
+		break;
+	default:
+		kdb_printf("kdb: unexpected reason code: %d\n", reason);
+		KDB_DEBUG_STATE("kdb_local 8", reason);
+		return 0;	/* Not for us, dismiss it */
+	}
+
+	while (1) {
+		/*
+		 * Initialize pager context.
+		 */
+		kdb_nextline = 1;
+		KDB_STATE_CLEAR(SUPPRESS);
+		kdb_grepping_flag = 0;
+		/* ensure the old search does not leak into '/' commands */
+		kdb_grep_string[0] = '\0';
+
+		cmdbuf = cmd_cur;
+		*cmdbuf = '\0';
+		*(cmd_hist[cmd_head]) = '\0';
+
+do_full_getstr:
+		/* PROMPT can only be set if we have MEM_READ permission. */
+		snprintf(kdb_prompt_str, CMD_BUFLEN, kdbgetenv("PROMPT"),
+			 raw_smp_processor_id());
+
+		/*
+		 * Fetch command from keyboard
+		 */
+		cmdbuf = kdb_getstr(cmdbuf, CMD_BUFLEN, kdb_prompt_str);
+		if (*cmdbuf != '\n') {
+			if (*cmdbuf < 32) {
+				if (cmdptr == cmd_head) {
+					strscpy(cmd_hist[cmd_head], cmd_cur,
+						CMD_BUFLEN);
+					*(cmd_hist[cmd_head] +
+					  strlen(cmd_hist[cmd_head])-1) = '\0';
+				}
+				if (!handle_ctrl_cmd(cmdbuf))
+					*(cmd_cur+strlen(cmd_cur)-1) = '\0';
+				cmdbuf = cmd_cur;
+				goto do_full_getstr;
+			} else {
+				strscpy(cmd_hist[cmd_head], cmd_cur,
+					CMD_BUFLEN);
+			}
+
+			cmd_head = (cmd_head+1) % KDB_CMD_HISTORY_COUNT;
+			if (cmd_head == cmd_tail)
+				cmd_tail = (cmd_tail+1) % KDB_CMD_HISTORY_COUNT;
+		}
+
+		cmdptr = cmd_head;
+		diag = kdb_parse(cmdbuf);
+		if (diag == KDB_NOTFOUND) {
+			drop_newline(cmdbuf);
+			kdb_printf("Unknown kdb command: '%s'\n", cmdbuf);
+			diag = 0;
+		}
+		if (diag == KDB_CMD_GO
+		 || diag == KDB_CMD_CPU
+		 || diag == KDB_CMD_SS
+		 || diag == KDB_CMD_KGDB)
+			break;
+
+		if (diag)
+			kdb_cmderror(diag);
+	}
+	KDB_DEBUG_STATE("kdb_local 9", diag);
+	return diag;
+}
+
+
+/*
+ * kdb_print_state - Print the state data for the current processor
+ *	for debugging.
+ * Inputs:
+ *	text		Identifies the debug point
+ *	value		Any integer value to be printed, e.g. reason code.
+ */
+void kdb_print_state(const char *text, int value)
+{
+	kdb_printf("state: %s cpu %d value %d initial %d state %x\n",
+		   text, raw_smp_processor_id(), value, kdb_initial_cpu,
+		   kdb_state);
+}
+
+/*
+ * kdb_main_loop - After initial setup and assignment of the
+ *	controlling cpu, all cpus are in this loop.  One cpu is in
+ *	control and will issue the kdb prompt, the others will spin
+ *	until 'go' or cpu switch.
+ *
+ *	To get a consistent view of the kernel stacks for all
+ *	processes, this routine is invoked from the main kdb code via
+ *	an architecture specific routine.  kdba_main_loop is
+ *	responsible for making the kernel stacks consistent for all
+ *	processes, there should be no difference between a blocked
+ *	process and a running process as far as kdb is concerned.
+ * Inputs:
+ *	reason		The reason KDB was invoked
+ *	error		The hardware-defined error code
+ *	reason2		kdb's current reason code.
+ *			Initially error but can change
+ *			according to kdb state.
+ *	db_result	Result code from break or debug point.
+ *	regs		The exception frame at time of fault/breakpoint.
+ *			should always be valid.
+ * Returns:
+ *	0	KDB was invoked for an event which it wasn't responsible
+ *	1	KDB handled the event for which it was invoked.
+ */
+int kdb_main_loop(kdb_reason_t reason, kdb_reason_t reason2, int error,
+	      kdb_dbtrap_t db_result, struct pt_regs *regs)
+{
+	int result = 1;
+	/* Stay in kdb() until 'go', 'ss[b]' or an error */
+	while (1) {
+		/*
+		 * All processors except the one that is in control
+		 * will spin here.
+		 */
+		KDB_DEBUG_STATE("kdb_main_loop 1", reason);
+		while (KDB_STATE(HOLD_CPU)) {
+			/* state KDB is turned off by kdb_cpu to see if the
+			 * other cpus are still live, each cpu in this loop
+			 * turns it back on.
+			 */
+			if (!KDB_STATE(KDB))
+				KDB_STATE_SET(KDB);
+		}
+
+		KDB_STATE_CLEAR(SUPPRESS);
+		KDB_DEBUG_STATE("kdb_main_loop 2", reason);
+		if (KDB_STATE(LEAVING))
+			break;	/* Another cpu said 'go' */
+		/* Still using kdb, this processor is in control */
+		result = kdb_local(reason2, error, regs, db_result);
+		KDB_DEBUG_STATE("kdb_main_loop 3", result);
+
+		if (result == KDB_CMD_CPU)
+			break;
+
+		if (result == KDB_CMD_SS) {
+			KDB_STATE_SET(DOING_SS);
+			break;
+		}
+
+		if (result == KDB_CMD_KGDB) {
+			if (!KDB_STATE(DOING_KGDB))
+				kdb_printf("Entering please attach debugger "
+					   "or use $D#44+ or $3#33\n");
+			break;
+		}
+		if (result && result != 1 && result != KDB_CMD_GO)
+			kdb_printf("\nUnexpected kdb_local return code %d\n",
+				   result);
+		KDB_DEBUG_STATE("kdb_main_loop 4", reason);
+		break;
+	}
+	if (KDB_STATE(DOING_SS))
+		KDB_STATE_CLEAR(SSBPT);
+
+	/* Clean up any keyboard devices before leaving */
+	kdb_kbd_cleanup_state();
+
+	return result;
+}
+
+/*
+ * kdb_mdr - This function implements the guts of the 'mdr', memory
+ * read command.
+ *	mdr  <addr arg>,<byte count>
+ * Inputs:
+ *	addr	Start address
+ *	count	Number of bytes
+ * Returns:
+ *	Always 0.  Any errors are detected and printed by kdb_getarea.
+ */
+static int kdb_mdr(unsigned long addr, unsigned int count)
+{
+	unsigned char c;
+	while (count--) {
+		if (kdb_getarea(c, addr))
+			return 0;
+		kdb_printf("%02x", c);
+		addr++;
+	}
+	kdb_printf("\n");
+	return 0;
+}
+
+/*
+ * kdb_md - This function implements the 'md', 'md1', 'md2', 'md4',
+ *	'md8' 'mdr' and 'mds' commands.
+ *
+ *	md|mds  [<addr arg> [<line count> [<radix>]]]
+ *	mdWcN	[<addr arg> [<line count> [<radix>]]]
+ *		where W = is the width (1, 2, 4 or 8) and N is the count.
+ *		for eg., md1c20 reads 20 bytes, 1 at a time.
+ *	mdr  <addr arg>,<byte count>
+ */
+static void kdb_md_line(const char *fmtstr, unsigned long addr,
+			int symbolic, int nosect, int bytesperword,
+			int num, int repeat, int phys)
+{
+	/* print just one line of data */
+	kdb_symtab_t symtab;
+	char cbuf[32];
+	char *c = cbuf;
+	int i;
+	int j;
+	unsigned long word;
+
+	memset(cbuf, '\0', sizeof(cbuf));
+	if (phys)
+		kdb_printf("phys " kdb_machreg_fmt0 " ", addr);
+	else
+		kdb_printf(kdb_machreg_fmt0 " ", addr);
+
+	for (i = 0; i < num && repeat--; i++) {
+		if (phys) {
+			if (kdb_getphysword(&word, addr, bytesperword))
+				break;
+		} else if (kdb_getword(&word, addr, bytesperword))
+			break;
+		kdb_printf(fmtstr, word);
+		if (symbolic)
+			kdbnearsym(word, &symtab);
+		else
+			memset(&symtab, 0, sizeof(symtab));
+		if (symtab.sym_name) {
+			kdb_symbol_print(word, &symtab, 0);
+			if (!nosect) {
+				kdb_printf("\n");
+				kdb_printf("                       %s %s "
+					   kdb_machreg_fmt " "
+					   kdb_machreg_fmt " "
+					   kdb_machreg_fmt, symtab.mod_name,
+					   symtab.sec_name, symtab.sec_start,
+					   symtab.sym_start, symtab.sym_end);
+			}
+			addr += bytesperword;
+		} else {
+			union {
+				u64 word;
+				unsigned char c[8];
+			} wc;
+			unsigned char *cp;
+#ifdef	__BIG_ENDIAN
+			cp = wc.c + 8 - bytesperword;
+#else
+			cp = wc.c;
+#endif
+			wc.word = word;
+#define printable_char(c) \
+	({unsigned char __c = c; isascii(__c) && isprint(__c) ? __c : '.'; })
+			for (j = 0; j < bytesperword; j++)
+				*c++ = printable_char(*cp++);
+			addr += bytesperword;
+#undef printable_char
+		}
+	}
+	kdb_printf("%*s %s\n", (int)((num-i)*(2*bytesperword + 1)+1),
+		   " ", cbuf);
+}
+
+static int kdb_md(int argc, const char **argv)
+{
+	static unsigned long last_addr;
+	static int last_radix, last_bytesperword, last_repeat;
+	int radix = 16, mdcount = 8, bytesperword = KDB_WORD_SIZE, repeat;
+	int nosect = 0;
+	char fmtchar, fmtstr[64];
+	unsigned long addr;
+	unsigned long word;
+	long offset = 0;
+	int symbolic = 0;
+	int valid = 0;
+	int phys = 0;
+	int raw = 0;
+
+	kdbgetintenv("MDCOUNT", &mdcount);
+	kdbgetintenv("RADIX", &radix);
+	kdbgetintenv("BYTESPERWORD", &bytesperword);
+
+	/* Assume 'md <addr>' and start with environment values */
+	repeat = mdcount * 16 / bytesperword;
+
+	if (strcmp(argv[0], "mdr") == 0) {
+		if (argc == 2 || (argc == 0 && last_addr != 0))
+			valid = raw = 1;
+		else
+			return KDB_ARGCOUNT;
+	} else if (isdigit(argv[0][2])) {
+		bytesperword = (int)(argv[0][2] - '0');
+		if (bytesperword == 0) {
+			bytesperword = last_bytesperword;
+			if (bytesperword == 0)
+				bytesperword = 4;
+		}
+		last_bytesperword = bytesperword;
+		repeat = mdcount * 16 / bytesperword;
+		if (!argv[0][3])
+			valid = 1;
+		else if (argv[0][3] == 'c' && argv[0][4]) {
+			char *p;
+			repeat = simple_strtoul(argv[0] + 4, &p, 10);
+			mdcount = ((repeat * bytesperword) + 15) / 16;
+			valid = !*p;
+		}
+		last_repeat = repeat;
+	} else if (strcmp(argv[0], "md") == 0)
+		valid = 1;
+	else if (strcmp(argv[0], "mds") == 0)
+		valid = 1;
+	else if (strcmp(argv[0], "mdp") == 0) {
+		phys = valid = 1;
+	}
+	if (!valid)
+		return KDB_NOTFOUND;
+
+	if (argc == 0) {
+		if (last_addr == 0)
+			return KDB_ARGCOUNT;
+		addr = last_addr;
+		radix = last_radix;
+		bytesperword = last_bytesperword;
+		repeat = last_repeat;
+		if (raw)
+			mdcount = repeat;
+		else
+			mdcount = ((repeat * bytesperword) + 15) / 16;
+	}
+
+	if (argc) {
+		unsigned long val;
+		int diag, nextarg = 1;
+		diag = kdbgetaddrarg(argc, argv, &nextarg, &addr,
+				     &offset, NULL);
+		if (diag)
+			return diag;
+		if (argc > nextarg+2)
+			return KDB_ARGCOUNT;
+
+		if (argc >= nextarg) {
+			diag = kdbgetularg(argv[nextarg], &val);
+			if (!diag) {
+				mdcount = (int) val;
+				if (raw)
+					repeat = mdcount;
+				else
+					repeat = mdcount * 16 / bytesperword;
+			}
+		}
+		if (argc >= nextarg+1) {
+			diag = kdbgetularg(argv[nextarg+1], &val);
+			if (!diag)
+				radix = (int) val;
+		}
+	}
+
+	if (strcmp(argv[0], "mdr") == 0) {
+		int ret;
+		last_addr = addr;
+		ret = kdb_mdr(addr, mdcount);
+		last_addr += mdcount;
+		last_repeat = mdcount;
+		last_bytesperword = bytesperword; // to make REPEAT happy
+		return ret;
+	}
+
+	switch (radix) {
+	case 10:
+		fmtchar = 'd';
+		break;
+	case 16:
+		fmtchar = 'x';
+		break;
+	case 8:
+		fmtchar = 'o';
+		break;
+	default:
+		return KDB_BADRADIX;
+	}
+
+	last_radix = radix;
+
+	if (bytesperword > KDB_WORD_SIZE)
+		return KDB_BADWIDTH;
+
+	switch (bytesperword) {
+	case 8:
+		sprintf(fmtstr, "%%16.16l%c ", fmtchar);
+		break;
+	case 4:
+		sprintf(fmtstr, "%%8.8l%c ", fmtchar);
+		break;
+	case 2:
+		sprintf(fmtstr, "%%4.4l%c ", fmtchar);
+		break;
+	case 1:
+		sprintf(fmtstr, "%%2.2l%c ", fmtchar);
+		break;
+	default:
+		return KDB_BADWIDTH;
+	}
+
+	last_repeat = repeat;
+	last_bytesperword = bytesperword;
+
+	if (strcmp(argv[0], "mds") == 0) {
+		symbolic = 1;
+		/* Do not save these changes as last_*, they are temporary mds
+		 * overrides.
+		 */
+		bytesperword = KDB_WORD_SIZE;
+		repeat = mdcount;
+		kdbgetintenv("NOSECT", &nosect);
+	}
+
+	/* Round address down modulo BYTESPERWORD */
+
+	addr &= ~(bytesperword-1);
+
+	while (repeat > 0) {
+		unsigned long a;
+		int n, z, num = (symbolic ? 1 : (16 / bytesperword));
+
+		if (KDB_FLAG(CMD_INTERRUPT))
+			return 0;
+		for (a = addr, z = 0; z < repeat; a += bytesperword, ++z) {
+			if (phys) {
+				if (kdb_getphysword(&word, a, bytesperword)
+						|| word)
+					break;
+			} else if (kdb_getword(&word, a, bytesperword) || word)
+				break;
+		}
+		n = min(num, repeat);
+		kdb_md_line(fmtstr, addr, symbolic, nosect, bytesperword,
+			    num, repeat, phys);
+		addr += bytesperword * n;
+		repeat -= n;
+		z = (z + num - 1) / num;
+		if (z > 2) {
+			int s = num * (z-2);
+			kdb_printf(kdb_machreg_fmt0 "-" kdb_machreg_fmt0
+				   " zero suppressed\n",
+				addr, addr + bytesperword * s - 1);
+			addr += bytesperword * s;
+			repeat -= s;
+		}
+	}
+	last_addr = addr;
+
+	return 0;
+}
+
+/*
+ * kdb_mm - This function implements the 'mm' command.
+ *	mm address-expression new-value
+ * Remarks:
+ *	mm works on machine words, mmW works on bytes.
+ */
+static int kdb_mm(int argc, const char **argv)
+{
+	int diag;
+	unsigned long addr;
+	long offset = 0;
+	unsigned long contents;
+	int nextarg;
+	int width;
+
+	if (argv[0][2] && !isdigit(argv[0][2]))
+		return KDB_NOTFOUND;
+
+	if (argc < 2)
+		return KDB_ARGCOUNT;
+
+	nextarg = 1;
+	diag = kdbgetaddrarg(argc, argv, &nextarg, &addr, &offset, NULL);
+	if (diag)
+		return diag;
+
+	if (nextarg > argc)
+		return KDB_ARGCOUNT;
+	diag = kdbgetaddrarg(argc, argv, &nextarg, &contents, NULL, NULL);
+	if (diag)
+		return diag;
+
+	if (nextarg != argc + 1)
+		return KDB_ARGCOUNT;
+
+	width = argv[0][2] ? (argv[0][2] - '0') : (KDB_WORD_SIZE);
+	diag = kdb_putword(addr, contents, width);
+	if (diag)
+		return diag;
+
+	kdb_printf(kdb_machreg_fmt " = " kdb_machreg_fmt "\n", addr, contents);
+
+	return 0;
+}
+
+/*
+ * kdb_go - This function implements the 'go' command.
+ *	go [address-expression]
+ */
+static int kdb_go(int argc, const char **argv)
+{
+	unsigned long addr;
+	int diag;
+	int nextarg;
+	long offset;
+
+	if (raw_smp_processor_id() != kdb_initial_cpu) {
+		kdb_printf("go must execute on the entry cpu, "
+			   "please use \"cpu %d\" and then execute go\n",
+			   kdb_initial_cpu);
+		return KDB_BADCPUNUM;
+	}
+	if (argc == 1) {
+		nextarg = 1;
+		diag = kdbgetaddrarg(argc, argv, &nextarg,
+				     &addr, &offset, NULL);
+		if (diag)
+			return diag;
+	} else if (argc) {
+		return KDB_ARGCOUNT;
+	}
+
+	diag = KDB_CMD_GO;
+	if (KDB_FLAG(CATASTROPHIC)) {
+		kdb_printf("Catastrophic error detected\n");
+		kdb_printf("kdb_continue_catastrophic=%d, ",
+			kdb_continue_catastrophic);
+		if (kdb_continue_catastrophic == 0 && kdb_go_count++ == 0) {
+			kdb_printf("type go a second time if you really want "
+				   "to continue\n");
+			return 0;
+		}
+		if (kdb_continue_catastrophic == 2) {
+			kdb_printf("forcing reboot\n");
+			kdb_reboot(0, NULL);
+		}
+		kdb_printf("attempting to continue\n");
+	}
+	return diag;
+}
+
+/*
+ * kdb_rd - This function implements the 'rd' command.
+ */
+static int kdb_rd(int argc, const char **argv)
+{
+	int len = kdb_check_regs();
+#if DBG_MAX_REG_NUM > 0
+	int i;
+	char *rname;
+	int rsize;
+	u64 reg64;
+	u32 reg32;
+	u16 reg16;
+	u8 reg8;
+
+	if (len)
+		return len;
+
+	for (i = 0; i < DBG_MAX_REG_NUM; i++) {
+		rsize = dbg_reg_def[i].size * 2;
+		if (rsize > 16)
+			rsize = 2;
+		if (len + strlen(dbg_reg_def[i].name) + 4 + rsize > 80) {
+			len = 0;
+			kdb_printf("\n");
+		}
+		if (len)
+			len += kdb_printf("  ");
+		switch(dbg_reg_def[i].size * 8) {
+		case 8:
+			rname = dbg_get_reg(i, &reg8, kdb_current_regs);
+			if (!rname)
+				break;
+			len += kdb_printf("%s: %02x", rname, reg8);
+			break;
+		case 16:
+			rname = dbg_get_reg(i, &reg16, kdb_current_regs);
+			if (!rname)
+				break;
+			len += kdb_printf("%s: %04x", rname, reg16);
+			break;
+		case 32:
+			rname = dbg_get_reg(i, &reg32, kdb_current_regs);
+			if (!rname)
+				break;
+			len += kdb_printf("%s: %08x", rname, reg32);
+			break;
+		case 64:
+			rname = dbg_get_reg(i, &reg64, kdb_current_regs);
+			if (!rname)
+				break;
+			len += kdb_printf("%s: %016llx", rname, reg64);
+			break;
+		default:
+			len += kdb_printf("%s: ??", dbg_reg_def[i].name);
+		}
+	}
+	kdb_printf("\n");
+#else
+	if (len)
+		return len;
+
+	kdb_dumpregs(kdb_current_regs);
+#endif
+	return 0;
+}
+
+/*
+ * kdb_rm - This function implements the 'rm' (register modify)  command.
+ *	rm register-name new-contents
+ * Remarks:
+ *	Allows register modification with the same restrictions as gdb
+ */
+static int kdb_rm(int argc, const char **argv)
+{
+#if DBG_MAX_REG_NUM > 0
+	int diag;
+	const char *rname;
+	int i;
+	u64 reg64;
+	u32 reg32;
+	u16 reg16;
+	u8 reg8;
+
+	if (argc != 2)
+		return KDB_ARGCOUNT;
+	/*
+	 * Allow presence or absence of leading '%' symbol.
+	 */
+	rname = argv[1];
+	if (*rname == '%')
+		rname++;
+
+	diag = kdbgetu64arg(argv[2], &reg64);
+	if (diag)
+		return diag;
+
+	diag = kdb_check_regs();
+	if (diag)
+		return diag;
+
+	diag = KDB_BADREG;
+	for (i = 0; i < DBG_MAX_REG_NUM; i++) {
+		if (strcmp(rname, dbg_reg_def[i].name) == 0) {
+			diag = 0;
+			break;
+		}
+	}
+	if (!diag) {
+		switch(dbg_reg_def[i].size * 8) {
+		case 8:
+			reg8 = reg64;
+			dbg_set_reg(i, &reg8, kdb_current_regs);
+			break;
+		case 16:
+			reg16 = reg64;
+			dbg_set_reg(i, &reg16, kdb_current_regs);
+			break;
+		case 32:
+			reg32 = reg64;
+			dbg_set_reg(i, &reg32, kdb_current_regs);
+			break;
+		case 64:
+			dbg_set_reg(i, &reg64, kdb_current_regs);
+			break;
+		}
+	}
+	return diag;
+#else
+	kdb_printf("ERROR: Register set currently not implemented\n");
+    return 0;
+#endif
+}
+
+#if defined(CONFIG_MAGIC_SYSRQ)
+/*
+ * kdb_sr - This function implements the 'sr' (SYSRQ key) command
+ *	which interfaces to the soi-disant MAGIC SYSRQ functionality.
+ *		sr <magic-sysrq-code>
+ */
+static int kdb_sr(int argc, const char **argv)
+{
+	bool check_mask =
+	    !kdb_check_flags(KDB_ENABLE_ALL, kdb_cmd_enabled, false);
+
+	if (argc != 1)
+		return KDB_ARGCOUNT;
+
+	kdb_trap_printk++;
+	__handle_sysrq(*argv[1], check_mask);
+	kdb_trap_printk--;
+
+	return 0;
+}
+#endif	/* CONFIG_MAGIC_SYSRQ */
+
+/*
+ * kdb_ef - This function implements the 'regs' (display exception
+ *	frame) command.  This command takes an address and expects to
+ *	find an exception frame at that address, formats and prints
+ *	it.
+ *		regs address-expression
+ * Remarks:
+ *	Not done yet.
+ */
+static int kdb_ef(int argc, const char **argv)
+{
+	int diag;
+	unsigned long addr;
+	long offset;
+	int nextarg;
+
+	if (argc != 1)
+		return KDB_ARGCOUNT;
+
+	nextarg = 1;
+	diag = kdbgetaddrarg(argc, argv, &nextarg, &addr, &offset, NULL);
+	if (diag)
+		return diag;
+	show_regs((struct pt_regs *)addr);
+	return 0;
+}
+
+#if defined(CONFIG_MODULES)
+/*
+ * kdb_lsmod - This function implements the 'lsmod' command.  Lists
+ *	currently loaded kernel modules.
+ *	Mostly taken from userland lsmod.
+ */
+static int kdb_lsmod(int argc, const char **argv)
+{
+	struct module *mod;
+
+	if (argc != 0)
+		return KDB_ARGCOUNT;
+
+	kdb_printf("Module                  Size  modstruct     Used by\n");
+	list_for_each_entry(mod, kdb_modules, list) {
+		if (mod->state == MODULE_STATE_UNFORMED)
+			continue;
+
+		kdb_printf("%-20s%8u  0x%px ", mod->name,
+			   mod->core_layout.size, (void *)mod);
+#ifdef CONFIG_MODULE_UNLOAD
+		kdb_printf("%4d ", module_refcount(mod));
+#endif
+		if (mod->state == MODULE_STATE_GOING)
+			kdb_printf(" (Unloading)");
+		else if (mod->state == MODULE_STATE_COMING)
+			kdb_printf(" (Loading)");
+		else
+			kdb_printf(" (Live)");
+		kdb_printf(" 0x%px", mod->core_layout.base);
+
+#ifdef CONFIG_MODULE_UNLOAD
+		{
+			struct module_use *use;
+			kdb_printf(" [ ");
+			list_for_each_entry(use, &mod->source_list,
+					    source_list)
+				kdb_printf("%s ", use->target->name);
+			kdb_printf("]\n");
+		}
+#endif
+	}
+
+	return 0;
+}
+
+#endif	/* CONFIG_MODULES */
+
+/*
+ * kdb_env - This function implements the 'env' command.  Display the
+ *	current environment variables.
+ */
+
+static int kdb_env(int argc, const char **argv)
+{
+	int i;
+
+	for (i = 0; i < __nenv; i++) {
+		if (__env[i])
+			kdb_printf("%s\n", __env[i]);
+	}
+
+	if (KDB_DEBUG(MASK))
+		kdb_printf("KDBDEBUG=0x%x\n",
+			(kdb_flags & KDB_DEBUG(MASK)) >> KDB_DEBUG_FLAG_SHIFT);
+
+	return 0;
+}
+
+#ifdef CONFIG_PRINTK
+/*
+ * kdb_dmesg - This function implements the 'dmesg' command to display
+ *	the contents of the syslog buffer.
+ *		dmesg [lines] [adjust]
+ */
+static int kdb_dmesg(int argc, const char **argv)
+{
+	int diag;
+	int logging;
+	int lines = 0;
+	int adjust = 0;
+	int n = 0;
+	int skip = 0;
+	struct kmsg_dumper dumper = { .active = 1 };
+	size_t len;
+	char buf[201];
+
+	if (argc > 2)
+		return KDB_ARGCOUNT;
+	if (argc) {
+		char *cp;
+		lines = simple_strtol(argv[1], &cp, 0);
+		if (*cp)
+			lines = 0;
+		if (argc > 1) {
+			adjust = simple_strtoul(argv[2], &cp, 0);
+			if (*cp || adjust < 0)
+				adjust = 0;
+		}
+	}
+
+	/* disable LOGGING if set */
+	diag = kdbgetintenv("LOGGING", &logging);
+	if (!diag && logging) {
+		const char *setargs[] = { "set", "LOGGING", "0" };
+		kdb_set(2, setargs);
+	}
+
+	kmsg_dump_rewind_nolock(&dumper);
+	while (kmsg_dump_get_line_nolock(&dumper, 1, NULL, 0, NULL))
+		n++;
+
+	if (lines < 0) {
+		if (adjust >= n)
+			kdb_printf("buffer only contains %d lines, nothing "
+				   "printed\n", n);
+		else if (adjust - lines >= n)
+			kdb_printf("buffer only contains %d lines, last %d "
+				   "lines printed\n", n, n - adjust);
+		skip = adjust;
+		lines = abs(lines);
+	} else if (lines > 0) {
+		skip = n - lines - adjust;
+		lines = abs(lines);
+		if (adjust >= n) {
+			kdb_printf("buffer only contains %d lines, "
+				   "nothing printed\n", n);
+			skip = n;
+		} else if (skip < 0) {
+			lines += skip;
+			skip = 0;
+			kdb_printf("buffer only contains %d lines, first "
+				   "%d lines printed\n", n, lines);
+		}
+	} else {
+		lines = n;
+	}
+
+	if (skip >= n || skip < 0)
+		return 0;
+
+	kmsg_dump_rewind_nolock(&dumper);
+	while (kmsg_dump_get_line_nolock(&dumper, 1, buf, sizeof(buf), &len)) {
+		if (skip) {
+			skip--;
+			continue;
+		}
+		if (!lines--)
+			break;
+		if (KDB_FLAG(CMD_INTERRUPT))
+			return 0;
+
+		kdb_printf("%.*s\n", (int)len - 1, buf);
+	}
+
+	return 0;
+}
+#endif /* CONFIG_PRINTK */
+
+/* Make sure we balance enable/disable calls, must disable first. */
+static atomic_t kdb_nmi_disabled;
+
+static int kdb_disable_nmi(int argc, const char *argv[])
+{
+	if (atomic_read(&kdb_nmi_disabled))
+		return 0;
+	atomic_set(&kdb_nmi_disabled, 1);
+	arch_kgdb_ops.enable_nmi(0);
+	return 0;
+}
+
+static int kdb_param_enable_nmi(const char *val, const struct kernel_param *kp)
+{
+	if (!atomic_add_unless(&kdb_nmi_disabled, -1, 0))
+		return -EINVAL;
+	arch_kgdb_ops.enable_nmi(1);
+	return 0;
+}
+
+static const struct kernel_param_ops kdb_param_ops_enable_nmi = {
+	.set = kdb_param_enable_nmi,
+};
+module_param_cb(enable_nmi, &kdb_param_ops_enable_nmi, NULL, 0600);
+
+/*
+ * kdb_cpu - This function implements the 'cpu' command.
+ *	cpu	[<cpunum>]
+ * Returns:
+ *	KDB_CMD_CPU for success, a kdb diagnostic if error
+ */
+static void kdb_cpu_status(void)
+{
+	int i, start_cpu, first_print = 1;
+	char state, prev_state = '?';
+
+	kdb_printf("Currently on cpu %d\n", raw_smp_processor_id());
+	kdb_printf("Available cpus: ");
+	for (start_cpu = -1, i = 0; i < NR_CPUS; i++) {
+		if (!cpu_online(i)) {
+			state = 'F';	/* cpu is offline */
+		} else if (!kgdb_info[i].enter_kgdb) {
+			state = 'D';	/* cpu is online but unresponsive */
+		} else {
+			state = ' ';	/* cpu is responding to kdb */
+			if (kdb_task_state_char(KDB_TSK(i)) == 'I')
+				state = 'I';	/* idle task */
+		}
+		if (state != prev_state) {
+			if (prev_state != '?') {
+				if (!first_print)
+					kdb_printf(", ");
+				first_print = 0;
+				kdb_printf("%d", start_cpu);
+				if (start_cpu < i-1)
+					kdb_printf("-%d", i-1);
+				if (prev_state != ' ')
+					kdb_printf("(%c)", prev_state);
+			}
+			prev_state = state;
+			start_cpu = i;
+		}
+	}
+	/* print the trailing cpus, ignoring them if they are all offline */
+	if (prev_state != 'F') {
+		if (!first_print)
+			kdb_printf(", ");
+		kdb_printf("%d", start_cpu);
+		if (start_cpu < i-1)
+			kdb_printf("-%d", i-1);
+		if (prev_state != ' ')
+			kdb_printf("(%c)", prev_state);
+	}
+	kdb_printf("\n");
+}
+
+static int kdb_cpu(int argc, const char **argv)
+{
+	unsigned long cpunum;
+	int diag;
+
+	if (argc == 0) {
+		kdb_cpu_status();
+		return 0;
+	}
+
+	if (argc != 1)
+		return KDB_ARGCOUNT;
+
+	diag = kdbgetularg(argv[1], &cpunum);
+	if (diag)
+		return diag;
+
+	/*
+	 * Validate cpunum
+	 */
+	if ((cpunum >= CONFIG_NR_CPUS) || !kgdb_info[cpunum].enter_kgdb)
+		return KDB_BADCPUNUM;
+
+	dbg_switch_cpu = cpunum;
+
+	/*
+	 * Switch to other cpu
+	 */
+	return KDB_CMD_CPU;
+}
+
+/* The user may not realize that ps/bta with no parameters does not print idle
+ * or sleeping system daemon processes, so tell them how many were suppressed.
+ */
+void kdb_ps_suppressed(void)
+{
+	int idle = 0, daemon = 0;
+	unsigned long mask_I = kdb_task_state_string("I"),
+		      mask_M = kdb_task_state_string("M");
+	unsigned long cpu;
+	const struct task_struct *p, *g;
+	for_each_online_cpu(cpu) {
+		p = kdb_curr_task(cpu);
+		if (kdb_task_state(p, mask_I))
+			++idle;
+	}
+	for_each_process_thread(g, p) {
+		if (kdb_task_state(p, mask_M))
+			++daemon;
+	}
+	if (idle || daemon) {
+		if (idle)
+			kdb_printf("%d idle process%s (state I)%s\n",
+				   idle, idle == 1 ? "" : "es",
+				   daemon ? " and " : "");
+		if (daemon)
+			kdb_printf("%d sleeping system daemon (state M) "
+				   "process%s", daemon,
+				   daemon == 1 ? "" : "es");
+		kdb_printf(" suppressed,\nuse 'ps A' to see all.\n");
+	}
+}
+
+/*
+ * kdb_ps - This function implements the 'ps' command which shows a
+ *	list of the active processes.
+ *		ps [DRSTCZEUIMA]   All processes, optionally filtered by state
+ */
+void kdb_ps1(const struct task_struct *p)
+{
+	int cpu;
+	unsigned long tmp;
+
+	if (!p ||
+	    copy_from_kernel_nofault(&tmp, (char *)p, sizeof(unsigned long)))
+		return;
+
+	cpu = kdb_process_cpu(p);
+	kdb_printf("0x%px %8d %8d  %d %4d   %c  0x%px %c%s\n",
+		   (void *)p, p->pid, p->parent->pid,
+		   kdb_task_has_cpu(p), kdb_process_cpu(p),
+		   kdb_task_state_char(p),
+		   (void *)(&p->thread),
+		   p == kdb_curr_task(raw_smp_processor_id()) ? '*' : ' ',
+		   p->comm);
+	if (kdb_task_has_cpu(p)) {
+		if (!KDB_TSK(cpu)) {
+			kdb_printf("  Error: no saved data for this cpu\n");
+		} else {
+			if (KDB_TSK(cpu) != p)
+				kdb_printf("  Error: does not match running "
+				   "process table (0x%px)\n", KDB_TSK(cpu));
+		}
+	}
+}
+
+static int kdb_ps(int argc, const char **argv)
+{
+	struct task_struct *g, *p;
+	unsigned long mask, cpu;
+
+	if (argc == 0)
+		kdb_ps_suppressed();
+	kdb_printf("%-*s      Pid   Parent [*] cpu State %-*s Command\n",
+		(int)(2*sizeof(void *))+2, "Task Addr",
+		(int)(2*sizeof(void *))+2, "Thread");
+	mask = kdb_task_state_string(argc ? argv[1] : NULL);
+	/* Run the active tasks first */
+	for_each_online_cpu(cpu) {
+		if (KDB_FLAG(CMD_INTERRUPT))
+			return 0;
+		p = kdb_curr_task(cpu);
+		if (kdb_task_state(p, mask))
+			kdb_ps1(p);
+	}
+	kdb_printf("\n");
+	/* Now the real tasks */
+	for_each_process_thread(g, p) {
+		if (KDB_FLAG(CMD_INTERRUPT))
+			return 0;
+		if (kdb_task_state(p, mask))
+			kdb_ps1(p);
+	}
+
+	return 0;
+}
+
+/*
+ * kdb_pid - This function implements the 'pid' command which switches
+ *	the currently active process.
+ *		pid [<pid> | R]
+ */
+static int kdb_pid(int argc, const char **argv)
+{
+	struct task_struct *p;
+	unsigned long val;
+	int diag;
+
+	if (argc > 1)
+		return KDB_ARGCOUNT;
+
+	if (argc) {
+		if (strcmp(argv[1], "R") == 0) {
+			p = KDB_TSK(kdb_initial_cpu);
+		} else {
+			diag = kdbgetularg(argv[1], &val);
+			if (diag)
+				return KDB_BADINT;
+
+			p = find_task_by_pid_ns((pid_t)val,	&init_pid_ns);
+			if (!p) {
+				kdb_printf("No task with pid=%d\n", (pid_t)val);
+				return 0;
+			}
+		}
+		kdb_set_current_task(p);
+	}
+	kdb_printf("KDB current process is %s(pid=%d)\n",
+		   kdb_current_task->comm,
+		   kdb_current_task->pid);
+
+	return 0;
+}
+
+static int kdb_kgdb(int argc, const char **argv)
+{
+	return KDB_CMD_KGDB;
+}
+
+/*
+ * kdb_help - This function implements the 'help' and '?' commands.
+ */
+static int kdb_help(int argc, const char **argv)
+{
+	kdbtab_t *kt;
+	int i;
+
+	kdb_printf("%-15.15s %-20.20s %s\n", "Command", "Usage", "Description");
+	kdb_printf("-----------------------------"
+		   "-----------------------------\n");
+	for_each_kdbcmd(kt, i) {
+		char *space = "";
+		if (KDB_FLAG(CMD_INTERRUPT))
+			return 0;
+		if (!kt->cmd_name)
+			continue;
+		if (!kdb_check_flags(kt->cmd_flags, kdb_cmd_enabled, true))
+			continue;
+		if (strlen(kt->cmd_usage) > 20)
+			space = "\n                                    ";
+		kdb_printf("%-15.15s %-20s%s%s\n", kt->cmd_name,
+			   kt->cmd_usage, space, kt->cmd_help);
+	}
+	return 0;
+}
+
+/*
+ * kdb_kill - This function implements the 'kill' commands.
+ */
+static int kdb_kill(int argc, const char **argv)
+{
+	long sig, pid;
+	char *endp;
+	struct task_struct *p;
+
+	if (argc != 2)
+		return KDB_ARGCOUNT;
+
+	sig = simple_strtol(argv[1], &endp, 0);
+	if (*endp)
+		return KDB_BADINT;
+	if ((sig >= 0) || !valid_signal(-sig)) {
+		kdb_printf("Invalid signal parameter.<-signal>\n");
+		return 0;
+	}
+	sig = -sig;
+
+	pid = simple_strtol(argv[2], &endp, 0);
+	if (*endp)
+		return KDB_BADINT;
+	if (pid <= 0) {
+		kdb_printf("Process ID must be large than 0.\n");
+		return 0;
+	}
+
+	/* Find the process. */
+	p = find_task_by_pid_ns(pid, &init_pid_ns);
+	if (!p) {
+		kdb_printf("The specified process isn't found.\n");
+		return 0;
+	}
+	p = p->group_leader;
+	kdb_send_sig(p, sig);
+	return 0;
+}
+
+/*
+ * Most of this code has been lifted from kernel/timer.c::sys_sysinfo().
+ * I cannot call that code directly from kdb, it has an unconditional
+ * cli()/sti() and calls routines that take locks which can stop the debugger.
+ */
+static void kdb_sysinfo(struct sysinfo *val)
+{
+	u64 uptime = ktime_get_mono_fast_ns();
+
+	memset(val, 0, sizeof(*val));
+	val->uptime = div_u64(uptime, NSEC_PER_SEC);
+	val->loads[0] = avenrun[0];
+	val->loads[1] = avenrun[1];
+	val->loads[2] = avenrun[2];
+	val->procs = nr_threads-1;
+	si_meminfo(val);
+
+	return;
+}
+
+/*
+ * kdb_summary - This function implements the 'summary' command.
+ */
+static int kdb_summary(int argc, const char **argv)
+{
+	time64_t now;
+	struct tm tm;
+	struct sysinfo val;
+
+	if (argc)
+		return KDB_ARGCOUNT;
+
+	kdb_printf("sysname    %s\n", init_uts_ns.name.sysname);
+	kdb_printf("release    %s\n", init_uts_ns.name.release);
+	kdb_printf("version    %s\n", init_uts_ns.name.version);
+	kdb_printf("machine    %s\n", init_uts_ns.name.machine);
+	kdb_printf("nodename   %s\n", init_uts_ns.name.nodename);
+	kdb_printf("domainname %s\n", init_uts_ns.name.domainname);
+
+	now = __ktime_get_real_seconds();
+	time64_to_tm(now, 0, &tm);
+	kdb_printf("date       %04ld-%02d-%02d %02d:%02d:%02d "
+		   "tz_minuteswest %d\n",
+		1900+tm.tm_year, tm.tm_mon+1, tm.tm_mday,
+		tm.tm_hour, tm.tm_min, tm.tm_sec,
+		sys_tz.tz_minuteswest);
+
+	kdb_sysinfo(&val);
+	kdb_printf("uptime     ");
+	if (val.uptime > (24*60*60)) {
+		int days = val.uptime / (24*60*60);
+		val.uptime %= (24*60*60);
+		kdb_printf("%d day%s ", days, days == 1 ? "" : "s");
+	}
+	kdb_printf("%02ld:%02ld\n", val.uptime/(60*60), (val.uptime/60)%60);
+
+	kdb_printf("load avg   %ld.%02ld %ld.%02ld %ld.%02ld\n",
+		LOAD_INT(val.loads[0]), LOAD_FRAC(val.loads[0]),
+		LOAD_INT(val.loads[1]), LOAD_FRAC(val.loads[1]),
+		LOAD_INT(val.loads[2]), LOAD_FRAC(val.loads[2]));
+
+	/* Display in kilobytes */
+#define K(x) ((x) << (PAGE_SHIFT - 10))
+	kdb_printf("\nMemTotal:       %8lu kB\nMemFree:        %8lu kB\n"
+		   "Buffers:        %8lu kB\n",
+		   K(val.totalram), K(val.freeram), K(val.bufferram));
+	return 0;
+}
+
+/*
+ * kdb_per_cpu - This function implements the 'per_cpu' command.
+ */
+static int kdb_per_cpu(int argc, const char **argv)
+{
+	char fmtstr[64];
+	int cpu, diag, nextarg = 1;
+	unsigned long addr, symaddr, val, bytesperword = 0, whichcpu = ~0UL;
+
+	if (argc < 1 || argc > 3)
+		return KDB_ARGCOUNT;
+
+	diag = kdbgetaddrarg(argc, argv, &nextarg, &symaddr, NULL, NULL);
+	if (diag)
+		return diag;
+
+	if (argc >= 2) {
+		diag = kdbgetularg(argv[2], &bytesperword);
+		if (diag)
+			return diag;
+	}
+	if (!bytesperword)
+		bytesperword = KDB_WORD_SIZE;
+	else if (bytesperword > KDB_WORD_SIZE)
+		return KDB_BADWIDTH;
+	sprintf(fmtstr, "%%0%dlx ", (int)(2*bytesperword));
+	if (argc >= 3) {
+		diag = kdbgetularg(argv[3], &whichcpu);
+		if (diag)
+			return diag;
+		if (whichcpu >= nr_cpu_ids || !cpu_online(whichcpu)) {
+			kdb_printf("cpu %ld is not online\n", whichcpu);
+			return KDB_BADCPUNUM;
+		}
+	}
+
+	/* Most architectures use __per_cpu_offset[cpu], some use
+	 * __per_cpu_offset(cpu), smp has no __per_cpu_offset.
+	 */
+#ifdef	__per_cpu_offset
+#define KDB_PCU(cpu) __per_cpu_offset(cpu)
+#else
+#ifdef	CONFIG_SMP
+#define KDB_PCU(cpu) __per_cpu_offset[cpu]
+#else
+#define KDB_PCU(cpu) 0
+#endif
+#endif
+	for_each_online_cpu(cpu) {
+		if (KDB_FLAG(CMD_INTERRUPT))
+			return 0;
+
+		if (whichcpu != ~0UL && whichcpu != cpu)
+			continue;
+		addr = symaddr + KDB_PCU(cpu);
+		diag = kdb_getword(&val, addr, bytesperword);
+		if (diag) {
+			kdb_printf("%5d " kdb_bfd_vma_fmt0 " - unable to "
+				   "read, diag=%d\n", cpu, addr, diag);
+			continue;
+		}
+		kdb_printf("%5d ", cpu);
+		kdb_md_line(fmtstr, addr,
+			bytesperword == KDB_WORD_SIZE,
+			1, bytesperword, 1, 1, 0);
+	}
+#undef KDB_PCU
+	return 0;
+}
+
+/*
+ * display help for the use of cmd | grep pattern
+ */
+static int kdb_grep_help(int argc, const char **argv)
+{
+	kdb_printf("Usage of  cmd args | grep pattern:\n");
+	kdb_printf("  Any command's output may be filtered through an ");
+	kdb_printf("emulated 'pipe'.\n");
+	kdb_printf("  'grep' is just a key word.\n");
+	kdb_printf("  The pattern may include a very limited set of "
+		   "metacharacters:\n");
+	kdb_printf("   pattern or ^pattern or pattern$ or ^pattern$\n");
+	kdb_printf("  And if there are spaces in the pattern, you may "
+		   "quote it:\n");
+	kdb_printf("   \"pat tern\" or \"^pat tern\" or \"pat tern$\""
+		   " or \"^pat tern$\"\n");
+	return 0;
+}
+
+/*
+ * kdb_register_flags - This function is used to register a kernel
+ * 	debugger command.
+ * Inputs:
+ *	cmd	Command name
+ *	func	Function to execute the command
+ *	usage	A simple usage string showing arguments
+ *	help	A simple help string describing command
+ *	repeat	Does the command auto repeat on enter?
+ * Returns:
+ *	zero for success, one if a duplicate command.
+ */
+#define kdb_command_extend 50	/* arbitrary */
+int kdb_register_flags(char *cmd,
+		       kdb_func_t func,
+		       char *usage,
+		       char *help,
+		       short minlen,
+		       kdb_cmdflags_t flags)
+{
+	int i;
+	kdbtab_t *kp;
+
+	/*
+	 *  Brute force method to determine duplicates
+	 */
+	for_each_kdbcmd(kp, i) {
+		if (kp->cmd_name && (strcmp(kp->cmd_name, cmd) == 0)) {
+			kdb_printf("Duplicate kdb command registered: "
+				"%s, func %px help %s\n", cmd, func, help);
+			return 1;
+		}
+	}
+
+	/*
+	 * Insert command into first available location in table
+	 */
+	for_each_kdbcmd(kp, i) {
+		if (kp->cmd_name == NULL)
+			break;
+	}
+
+	if (i >= kdb_max_commands) {
+		kdbtab_t *new = kmalloc_array(kdb_max_commands -
+						KDB_BASE_CMD_MAX +
+						kdb_command_extend,
+					      sizeof(*new),
+					      GFP_KDB);
+		if (!new) {
+			kdb_printf("Could not allocate new kdb_command "
+				   "table\n");
+			return 1;
+		}
+		if (kdb_commands) {
+			memcpy(new, kdb_commands,
+			  (kdb_max_commands - KDB_BASE_CMD_MAX) * sizeof(*new));
+			kfree(kdb_commands);
+		}
+		memset(new + kdb_max_commands - KDB_BASE_CMD_MAX, 0,
+		       kdb_command_extend * sizeof(*new));
+		kdb_commands = new;
+		kp = kdb_commands + kdb_max_commands - KDB_BASE_CMD_MAX;
+		kdb_max_commands += kdb_command_extend;
+	}
+
+	kp->cmd_name   = cmd;
+	kp->cmd_func   = func;
+	kp->cmd_usage  = usage;
+	kp->cmd_help   = help;
+	kp->cmd_minlen = minlen;
+	kp->cmd_flags  = flags;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(kdb_register_flags);
+
+
+/*
+ * kdb_register - Compatibility register function for commands that do
+ *	not need to specify a repeat state.  Equivalent to
+ *	kdb_register_flags with flags set to 0.
+ * Inputs:
+ *	cmd	Command name
+ *	func	Function to execute the command
+ *	usage	A simple usage string showing arguments
+ *	help	A simple help string describing command
+ * Returns:
+ *	zero for success, one if a duplicate command.
+ */
+int kdb_register(char *cmd,
+	     kdb_func_t func,
+	     char *usage,
+	     char *help,
+	     short minlen)
+{
+	return kdb_register_flags(cmd, func, usage, help, minlen, 0);
+}
+EXPORT_SYMBOL_GPL(kdb_register);
+
+/*
+ * kdb_unregister - This function is used to unregister a kernel
+ *	debugger command.  It is generally called when a module which
+ *	implements kdb commands is unloaded.
+ * Inputs:
+ *	cmd	Command name
+ * Returns:
+ *	zero for success, one command not registered.
+ */
+int kdb_unregister(char *cmd)
+{
+	int i;
+	kdbtab_t *kp;
+
+	/*
+	 *  find the command.
+	 */
+	for_each_kdbcmd(kp, i) {
+		if (kp->cmd_name && (strcmp(kp->cmd_name, cmd) == 0)) {
+			kp->cmd_name = NULL;
+			return 0;
+		}
+	}
+
+	/* Couldn't find it.  */
+	return 1;
+}
+EXPORT_SYMBOL_GPL(kdb_unregister);
+
+/* Initialize the kdb command table. */
+static void __init kdb_inittab(void)
+{
+	int i;
+	kdbtab_t *kp;
+
+	for_each_kdbcmd(kp, i)
+		kp->cmd_name = NULL;
+
+	kdb_register_flags("md", kdb_md, "<vaddr>",
+	  "Display Memory Contents, also mdWcN, e.g. md8c1", 1,
+	  KDB_ENABLE_MEM_READ | KDB_REPEAT_NO_ARGS);
+	kdb_register_flags("mdr", kdb_md, "<vaddr> <bytes>",
+	  "Display Raw Memory", 0,
+	  KDB_ENABLE_MEM_READ | KDB_REPEAT_NO_ARGS);
+	kdb_register_flags("mdp", kdb_md, "<paddr> <bytes>",
+	  "Display Physical Memory", 0,
+	  KDB_ENABLE_MEM_READ | KDB_REPEAT_NO_ARGS);
+	kdb_register_flags("mds", kdb_md, "<vaddr>",
+	  "Display Memory Symbolically", 0,
+	  KDB_ENABLE_MEM_READ | KDB_REPEAT_NO_ARGS);
+	kdb_register_flags("mm", kdb_mm, "<vaddr> <contents>",
+	  "Modify Memory Contents", 0,
+	  KDB_ENABLE_MEM_WRITE | KDB_REPEAT_NO_ARGS);
+	kdb_register_flags("go", kdb_go, "[<vaddr>]",
+	  "Continue Execution", 1,
+	  KDB_ENABLE_REG_WRITE | KDB_ENABLE_ALWAYS_SAFE_NO_ARGS);
+	kdb_register_flags("rd", kdb_rd, "",
+	  "Display Registers", 0,
+	  KDB_ENABLE_REG_READ);
+	kdb_register_flags("rm", kdb_rm, "<reg> <contents>",
+	  "Modify Registers", 0,
+	  KDB_ENABLE_REG_WRITE);
+	kdb_register_flags("ef", kdb_ef, "<vaddr>",
+	  "Display exception frame", 0,
+	  KDB_ENABLE_MEM_READ);
+	kdb_register_flags("bt", kdb_bt, "[<vaddr>]",
+	  "Stack traceback", 1,
+	  KDB_ENABLE_MEM_READ | KDB_ENABLE_INSPECT_NO_ARGS);
+	kdb_register_flags("btp", kdb_bt, "<pid>",
+	  "Display stack for process <pid>", 0,
+	  KDB_ENABLE_INSPECT);
+	kdb_register_flags("bta", kdb_bt, "[D|R|S|T|C|Z|E|U|I|M|A]",
+	  "Backtrace all processes matching state flag", 0,
+	  KDB_ENABLE_INSPECT);
+	kdb_register_flags("btc", kdb_bt, "",
+	  "Backtrace current process on each cpu", 0,
+	  KDB_ENABLE_INSPECT);
+	kdb_register_flags("btt", kdb_bt, "<vaddr>",
+	  "Backtrace process given its struct task address", 0,
+	  KDB_ENABLE_MEM_READ | KDB_ENABLE_INSPECT_NO_ARGS);
+	kdb_register_flags("env", kdb_env, "",
+	  "Show environment variables", 0,
+	  KDB_ENABLE_ALWAYS_SAFE);
+	kdb_register_flags("set", kdb_set, "",
+	  "Set environment variables", 0,
+	  KDB_ENABLE_ALWAYS_SAFE);
+	kdb_register_flags("help", kdb_help, "",
+	  "Display Help Message", 1,
+	  KDB_ENABLE_ALWAYS_SAFE);
+	kdb_register_flags("?", kdb_help, "",
+	  "Display Help Message", 0,
+	  KDB_ENABLE_ALWAYS_SAFE);
+	kdb_register_flags("cpu", kdb_cpu, "<cpunum>",
+	  "Switch to new cpu", 0,
+	  KDB_ENABLE_ALWAYS_SAFE_NO_ARGS);
+	kdb_register_flags("kgdb", kdb_kgdb, "",
+	  "Enter kgdb mode", 0, 0);
+	kdb_register_flags("ps", kdb_ps, "[<flags>|A]",
+	  "Display active task list", 0,
+	  KDB_ENABLE_INSPECT);
+	kdb_register_flags("pid", kdb_pid, "<pidnum>",
+	  "Switch to another task", 0,
+	  KDB_ENABLE_INSPECT);
+	kdb_register_flags("reboot", kdb_reboot, "",
+	  "Reboot the machine immediately", 0,
+	  KDB_ENABLE_REBOOT);
+#if defined(CONFIG_MODULES)
+	kdb_register_flags("lsmod", kdb_lsmod, "",
+	  "List loaded kernel modules", 0,
+	  KDB_ENABLE_INSPECT);
+#endif
+#if defined(CONFIG_MAGIC_SYSRQ)
+	kdb_register_flags("sr", kdb_sr, "<key>",
+	  "Magic SysRq key", 0,
+	  KDB_ENABLE_ALWAYS_SAFE);
+#endif
+#if defined(CONFIG_PRINTK)
+	kdb_register_flags("dmesg", kdb_dmesg, "[lines]",
+	  "Display syslog buffer", 0,
+	  KDB_ENABLE_ALWAYS_SAFE);
+#endif
+	if (arch_kgdb_ops.enable_nmi) {
+		kdb_register_flags("disable_nmi", kdb_disable_nmi, "",
+		  "Disable NMI entry to KDB", 0,
+		  KDB_ENABLE_ALWAYS_SAFE);
+	}
+	kdb_register_flags("defcmd", kdb_defcmd, "name \"usage\" \"help\"",
+	  "Define a set of commands, down to endefcmd", 0,
+	  KDB_ENABLE_ALWAYS_SAFE);
+	kdb_register_flags("kill", kdb_kill, "<-signal> <pid>",
+	  "Send a signal to a process", 0,
+	  KDB_ENABLE_SIGNAL);
+	kdb_register_flags("summary", kdb_summary, "",
+	  "Summarize the system", 4,
+	  KDB_ENABLE_ALWAYS_SAFE);
+	kdb_register_flags("per_cpu", kdb_per_cpu, "<sym> [<bytes>] [<cpu>]",
+	  "Display per_cpu variables", 3,
+	  KDB_ENABLE_MEM_READ);
+	kdb_register_flags("grephelp", kdb_grep_help, "",
+	  "Display help on | grep", 0,
+	  KDB_ENABLE_ALWAYS_SAFE);
+}
+
+/* Execute any commands defined in kdb_cmds.  */
+static void __init kdb_cmd_init(void)
+{
+	int i, diag;
+	for (i = 0; kdb_cmds[i]; ++i) {
+		diag = kdb_parse(kdb_cmds[i]);
+		if (diag)
+			kdb_printf("kdb command %s failed, kdb diag %d\n",
+				kdb_cmds[i], diag);
+	}
+	if (defcmd_in_progress) {
+		kdb_printf("Incomplete 'defcmd' set, forcing endefcmd\n");
+		kdb_parse("endefcmd");
+	}
+}
+
+/* Initialize kdb_printf, breakpoint tables and kdb state */
+void __init kdb_init(int lvl)
+{
+	static int kdb_init_lvl = KDB_NOT_INITIALIZED;
+	int i;
+
+	if (kdb_init_lvl == KDB_INIT_FULL || lvl <= kdb_init_lvl)
+		return;
+	for (i = kdb_init_lvl; i < lvl; i++) {
+		switch (i) {
+		case KDB_NOT_INITIALIZED:
+			kdb_inittab();		/* Initialize Command Table */
+			kdb_initbptab();	/* Initialize Breakpoints */
+			break;
+		case KDB_INIT_EARLY:
+			kdb_cmd_init();		/* Build kdb_cmds tables */
+			break;
+		}
+	}
+	kdb_init_lvl = lvl;
+}