kdb: core for kgdb back end (1 of 2)

This patch contains only the kdb core.  Because the change set was
large, it was split.  The next patch in the series includes the
instrumentation into the core kernel which are mainly helper functions
for kdb.

This work is directly derived from kdb v4.4 found at:

ftp://oss.sgi.com/projects/kdb/download/v4.4/

The kdb internals have been re-organized to make them mostly platform
independent and to connect everything to the debug core which is used by
gdbstub (which has long been known as kgdb).

The original version of kdb was 58,000 lines worth of changes to
support x86.  From that implementation only the kdb shell, and basic
commands for memory access, runcontrol, lsmod, and dmesg where carried
forward.

This is a generic implementation which aims to cover all the current
architectures using the kgdb core: ppc, arm, x86, mips, sparc, sh and
blackfin.  More archictectures can be added by implementing the
architecture specific kgdb functions.

[mort@sgi.com: Compile fix with hugepages enabled]
[mort@sgi.com: Clean breakpoint code renaming kdba_ -> kdb_]
[mort@sgi.com: fix new line after printing registers]
[mort@sgi.com: Remove the concept of global vs. local breakpoints]
[mort@sgi.com: Rework kdb_si_swapinfo to use more generic name]
[mort@sgi.com: fix the information dump macros, remove 'arch' from the names]
[sfr@canb.auug.org.au: include fixup to include linux/slab.h]

CC: linux-arch@vger.kernel.org
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Martin Hicks <mort@sgi.com>

10 files changed, 5853 insertions, 0 deletions

diff --git a/kernel/debug/kdb/.gitignore b/kernel/debug/kdb/.gitignore
new file mode 100644
index 000000000000..396d12eda9e8
--- /dev/null
+++ b/kernel/debug/kdb/.gitignore
@@ -0,0 +1 @@
+gen-kdb_cmds.c
diff --git a/kernel/debug/kdb/Makefile b/kernel/debug/kdb/Makefile
new file mode 100644
index 000000000000..d1e925eddbcd
--- /dev/null
+++ b/kernel/debug/kdb/Makefile
@@ -0,0 +1,24 @@
+# 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) 2009 Wind River Systems, Inc. All Rights Reserved.
+#
+
+CCVERSION	:= $(shell $(CC) -v 2>&1 | sed -ne '$$p')
+obj-y := kdb_io.o kdb_main.o kdb_support.o kdb_bt.o gen-kdb_cmds.o kdb_bp.o kdb_debugger.o
+
+clean-files := gen-kdb_cmds.c
+
+quiet_cmd_gen-kdb = GENKDB  $@
+      cmd_gen-kdb = $(AWK) 'BEGIN {print "\#include <linux/stddef.h>"; print "\#include <linux/init.h>"} \
+		/^\#/{next} \
+		/^[ \t]*$$/{next} \
+		{gsub(/"/, "\\\"", $$0); \
+		  print "static __initdata char kdb_cmd" cmds++ "[] = \"" $$0 "\\n\";"} \
+		END {print "extern char *kdb_cmds[]; char __initdata *kdb_cmds[] = {"; for (i = 0; i < cmds; ++i) {print "  kdb_cmd" i ","}; print("  NULL\n};");}' \
+		$(filter-out %/Makefile,$^) > $@#
+
+$(obj)/gen-kdb_cmds.c:	$(src)/kdb_cmds $(src)/Makefile
+	$(call cmd,gen-kdb)
diff --git a/kernel/debug/kdb/kdb_bp.c b/kernel/debug/kdb/kdb_bp.c
new file mode 100644
index 000000000000..75bd9b3ebbb7
--- /dev/null
+++ b/kernel/debug/kdb/kdb_bp.c
@@ -0,0 +1,564 @@
+/*
+ * Kernel Debugger Architecture Independent Breakpoint Handler
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (c) 1999-2004 Silicon Graphics, Inc.  All Rights Reserved.
+ * Copyright (c) 2009 Wind River Systems, Inc.  All Rights Reserved.
+ */
+
+#include <linux/string.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/kdb.h>
+#include <linux/kgdb.h>
+#include <linux/smp.h>
+#include <linux/sched.h>
+#include <linux/interrupt.h>
+#include "kdb_private.h"
+
+/*
+ * Table of kdb_breakpoints
+ */
+kdb_bp_t kdb_breakpoints[KDB_MAXBPT];
+
+static void kdb_setsinglestep(struct pt_regs *regs)
+{
+	KDB_STATE_SET(DOING_SS);
+}
+
+static char *kdb_rwtypes[] = {
+	"Instruction(i)",
+	"Instruction(Register)",
+	"Data Write",
+	"I/O",
+	"Data Access"
+};
+
+static char *kdb_bptype(kdb_bp_t *bp)
+{
+	if (bp->bp_type < 0 || bp->bp_type > 4)
+		return "";
+
+	return kdb_rwtypes[bp->bp_type];
+}
+
+static int kdb_parsebp(int argc, const char **argv, int *nextargp, kdb_bp_t *bp)
+{
+	int nextarg = *nextargp;
+	int diag;
+
+	bp->bph_length = 1;
+	if ((argc + 1) != nextarg) {
+		if (strnicmp(argv[nextarg], "datar", sizeof("datar")) == 0)
+			bp->bp_type = BP_ACCESS_WATCHPOINT;
+		else if (strnicmp(argv[nextarg], "dataw", sizeof("dataw")) == 0)
+			bp->bp_type = BP_WRITE_WATCHPOINT;
+		else if (strnicmp(argv[nextarg], "inst", sizeof("inst")) == 0)
+			bp->bp_type = BP_HARDWARE_BREAKPOINT;
+		else
+			return KDB_ARGCOUNT;
+
+		bp->bph_length = 1;
+
+		nextarg++;
+
+		if ((argc + 1) != nextarg) {
+			unsigned long len;
+
+			diag = kdbgetularg((char *)argv[nextarg],
+					   &len);
+			if (diag)
+				return diag;
+
+
+			if (len > 8)
+				return KDB_BADLENGTH;
+
+			bp->bph_length = len;
+			nextarg++;
+		}
+
+		if ((argc + 1) != nextarg)
+			return KDB_ARGCOUNT;
+	}
+
+	*nextargp = nextarg;
+	return 0;
+}
+
+static int _kdb_bp_remove(kdb_bp_t *bp)
+{
+	int ret = 1;
+	if (!bp->bp_installed)
+		return ret;
+	if (!bp->bp_type)
+		ret = dbg_remove_sw_break(bp->bp_addr);
+	else
+		ret = arch_kgdb_ops.remove_hw_breakpoint(bp->bp_addr,
+			 bp->bph_length,
+			 bp->bp_type);
+	if (ret == 0)
+		bp->bp_installed = 0;
+	return ret;
+}
+
+static void kdb_handle_bp(struct pt_regs *regs, kdb_bp_t *bp)
+{
+	if (KDB_DEBUG(BP))
+		kdb_printf("regs->ip = 0x%lx\n", instruction_pointer(regs));
+
+	/*
+	 * Setup single step
+	 */
+	kdb_setsinglestep(regs);
+
+	/*
+	 * Reset delay attribute
+	 */
+	bp->bp_delay = 0;
+	bp->bp_delayed = 1;
+}
+
+static int _kdb_bp_install(struct pt_regs *regs, kdb_bp_t *bp)
+{
+	int ret;
+	/*
+	 * Install the breakpoint, if it is not already installed.
+	 */
+
+	if (KDB_DEBUG(BP))
+		kdb_printf("%s: bp_installed %d\n",
+			   __func__, bp->bp_installed);
+	if (!KDB_STATE(SSBPT))
+		bp->bp_delay = 0;
+	if (bp->bp_installed)
+		return 1;
+	if (bp->bp_delay || (bp->bp_delayed && KDB_STATE(DOING_SS))) {
+		if (KDB_DEBUG(BP))
+			kdb_printf("%s: delayed bp\n", __func__);
+		kdb_handle_bp(regs, bp);
+		return 0;
+	}
+	if (!bp->bp_type)
+		ret = dbg_set_sw_break(bp->bp_addr);
+	else
+		ret = arch_kgdb_ops.set_hw_breakpoint(bp->bp_addr,
+			 bp->bph_length,
+			 bp->bp_type);
+	if (ret == 0) {
+		bp->bp_installed = 1;
+	} else {
+		kdb_printf("%s: failed to set breakpoint at 0x%lx\n",
+			   __func__, bp->bp_addr);
+		return 1;
+	}
+	return 0;
+}
+
+/*
+ * kdb_bp_install
+ *
+ *	Install kdb_breakpoints prior to returning from the
+ *	kernel debugger.  This allows the kdb_breakpoints to be set
+ *	upon functions that are used internally by kdb, such as
+ *	printk().  This function is only called once per kdb session.
+ */
+void kdb_bp_install(struct pt_regs *regs)
+{
+	int i;
+
+	for (i = 0; i < KDB_MAXBPT; i++) {
+		kdb_bp_t *bp = &kdb_breakpoints[i];
+
+		if (KDB_DEBUG(BP)) {
+			kdb_printf("%s: bp %d bp_enabled %d\n",
+				   __func__, i, bp->bp_enabled);
+		}
+		if (bp->bp_enabled)
+			_kdb_bp_install(regs, bp);
+	}
+}
+
+/*
+ * kdb_bp_remove
+ *
+ *	Remove kdb_breakpoints upon entry to the kernel debugger.
+ *
+ * Parameters:
+ *	None.
+ * Outputs:
+ *	None.
+ * Returns:
+ *	None.
+ * Locking:
+ *	None.
+ * Remarks:
+ */
+void kdb_bp_remove(void)
+{
+	int i;
+
+	for (i = KDB_MAXBPT - 1; i >= 0; i--) {
+		kdb_bp_t *bp = &kdb_breakpoints[i];
+
+		if (KDB_DEBUG(BP)) {
+			kdb_printf("%s: bp %d bp_enabled %d\n",
+				   __func__, i, bp->bp_enabled);
+		}
+		if (bp->bp_enabled)
+			_kdb_bp_remove(bp);
+	}
+}
+
+
+/*
+ * kdb_printbp
+ *
+ *	Internal function to format and print a breakpoint entry.
+ *
+ * Parameters:
+ *	None.
+ * Outputs:
+ *	None.
+ * Returns:
+ *	None.
+ * Locking:
+ *	None.
+ * Remarks:
+ */
+
+static void kdb_printbp(kdb_bp_t *bp, int i)
+{
+	kdb_printf("%s ", kdb_bptype(bp));
+	kdb_printf("BP #%d at ", i);
+	kdb_symbol_print(bp->bp_addr, NULL, KDB_SP_DEFAULT);
+
+	if (bp->bp_enabled)
+		kdb_printf("\n    is enabled");
+	else
+		kdb_printf("\n    is disabled");
+
+	kdb_printf("\taddr at %016lx, hardtype=%d installed=%d\n",
+		   bp->bp_addr, bp->bp_type, bp->bp_installed);
+
+	kdb_printf("\n");
+}
+
+/*
+ * kdb_bp
+ *
+ *	Handle the bp commands.
+ *
+ *	[bp|bph] <addr-expression> [DATAR|DATAW]
+ *
+ * Parameters:
+ *	argc	Count of arguments in argv
+ *	argv	Space delimited command line arguments
+ * Outputs:
+ *	None.
+ * Returns:
+ *	Zero for success, a kdb diagnostic if failure.
+ * Locking:
+ *	None.
+ * Remarks:
+ *
+ *	bp	Set breakpoint on all cpus.  Only use hardware assist if need.
+ *	bph	Set breakpoint on all cpus.  Force hardware register
+ */
+
+static int kdb_bp(int argc, const char **argv)
+{
+	int i, bpno;
+	kdb_bp_t *bp, *bp_check;
+	int diag;
+	int free;
+	char *symname = NULL;
+	long offset = 0ul;
+	int nextarg;
+	kdb_bp_t template = {0};
+
+	if (argc == 0) {
+		/*
+		 * Display breakpoint table
+		 */
+		for (bpno = 0, bp = kdb_breakpoints; bpno < KDB_MAXBPT;
+		     bpno++, bp++) {
+			if (bp->bp_free)
+				continue;
+			kdb_printbp(bp, bpno);
+		}
+
+		return 0;
+	}
+
+	nextarg = 1;
+	diag = kdbgetaddrarg(argc, argv, &nextarg, &template.bp_addr,
+			     &offset, &symname);
+	if (diag)
+		return diag;
+	if (!template.bp_addr)
+		return KDB_BADINT;
+
+	/*
+	 * Find an empty bp structure to allocate
+	 */
+	free = KDB_MAXBPT;
+	for (bpno = 0, bp = kdb_breakpoints; bpno < KDB_MAXBPT; bpno++, bp++) {
+		if (bp->bp_free)
+			break;
+	}
+
+	if (bpno == KDB_MAXBPT)
+		return KDB_TOOMANYBPT;
+
+	if (strcmp(argv[0], "bph") == 0) {
+		template.bp_type = BP_HARDWARE_BREAKPOINT;
+		diag = kdb_parsebp(argc, argv, &nextarg, &template);
+		if (diag)
+			return diag;
+	} else {
+		template.bp_type = BP_BREAKPOINT;
+	}
+
+	/*
+	 * Check for clashing breakpoints.
+	 *
+	 * Note, in this design we can't have hardware breakpoints
+	 * enabled for both read and write on the same address.
+	 */
+	for (i = 0, bp_check = kdb_breakpoints; i < KDB_MAXBPT;
+	     i++, bp_check++) {
+		if (!bp_check->bp_free &&
+		    bp_check->bp_addr == template.bp_addr) {
+			kdb_printf("You already have a breakpoint at "
+				   kdb_bfd_vma_fmt0 "\n", template.bp_addr);
+			return KDB_DUPBPT;
+		}
+	}
+
+	template.bp_enabled = 1;
+
+	/*
+	 * Actually allocate the breakpoint found earlier
+	 */
+	*bp = template;
+	bp->bp_free = 0;
+
+	kdb_printbp(bp, bpno);
+
+	return 0;
+}
+
+/*
+ * kdb_bc
+ *
+ *	Handles the 'bc', 'be', and 'bd' commands
+ *
+ *	[bd|bc|be] <breakpoint-number>
+ *	[bd|bc|be] *
+ *
+ * Parameters:
+ *	argc	Count of arguments in argv
+ *	argv	Space delimited command line arguments
+ * Outputs:
+ *	None.
+ * Returns:
+ *	Zero for success, a kdb diagnostic for failure
+ * Locking:
+ *	None.
+ * Remarks:
+ */
+static int kdb_bc(int argc, const char **argv)
+{
+	unsigned long addr;
+	kdb_bp_t *bp = NULL;
+	int lowbp = KDB_MAXBPT;
+	int highbp = 0;
+	int done = 0;
+	int i;
+	int diag = 0;
+
+	int cmd;			/* KDBCMD_B? */
+#define KDBCMD_BC	0
+#define KDBCMD_BE	1
+#define KDBCMD_BD	2
+
+	if (strcmp(argv[0], "be") == 0)
+		cmd = KDBCMD_BE;
+	else if (strcmp(argv[0], "bd") == 0)
+		cmd = KDBCMD_BD;
+	else
+		cmd = KDBCMD_BC;
+
+	if (argc != 1)
+		return KDB_ARGCOUNT;
+
+	if (strcmp(argv[1], "*") == 0) {
+		lowbp = 0;
+		highbp = KDB_MAXBPT;
+	} else {
+		diag = kdbgetularg(argv[1], &addr);
+		if (diag)
+			return diag;
+
+		/*
+		 * For addresses less than the maximum breakpoint number,
+		 * assume that the breakpoint number is desired.
+		 */
+		if (addr < KDB_MAXBPT) {
+			bp = &kdb_breakpoints[addr];
+			lowbp = highbp = addr;
+			highbp++;
+		} else {
+			for (i = 0, bp = kdb_breakpoints; i < KDB_MAXBPT;
+			    i++, bp++) {
+				if (bp->bp_addr == addr) {
+					lowbp = highbp = i;
+					highbp++;
+					break;
+				}
+			}
+		}
+	}
+
+	/*
+	 * Now operate on the set of breakpoints matching the input
+	 * criteria (either '*' for all, or an individual breakpoint).
+	 */
+	for (bp = &kdb_breakpoints[lowbp], i = lowbp;
+	    i < highbp;
+	    i++, bp++) {
+		if (bp->bp_free)
+			continue;
+
+		done++;
+
+		switch (cmd) {
+		case KDBCMD_BC:
+			bp->bp_enabled = 0;
+
+			kdb_printf("Breakpoint %d at "
+				   kdb_bfd_vma_fmt " cleared\n",
+				   i, bp->bp_addr);
+
+			bp->bp_addr = 0;
+			bp->bp_free = 1;
+
+			break;
+		case KDBCMD_BE:
+			bp->bp_enabled = 1;
+
+			kdb_printf("Breakpoint %d at "
+				   kdb_bfd_vma_fmt " enabled",
+				   i, bp->bp_addr);
+
+			kdb_printf("\n");
+			break;
+		case KDBCMD_BD:
+			if (!bp->bp_enabled)
+				break;
+
+			bp->bp_enabled = 0;
+
+			kdb_printf("Breakpoint %d at "
+				   kdb_bfd_vma_fmt " disabled\n",
+				   i, bp->bp_addr);
+
+			break;
+		}
+		if (bp->bp_delay && (cmd == KDBCMD_BC || cmd == KDBCMD_BD)) {
+			bp->bp_delay = 0;
+			KDB_STATE_CLEAR(SSBPT);
+		}
+	}
+
+	return (!done) ? KDB_BPTNOTFOUND : 0;
+}
+
+/*
+ * kdb_ss
+ *
+ *	Process the 'ss' (Single Step) and 'ssb' (Single Step to Branch)
+ *	commands.
+ *
+ *	ss
+ *	ssb
+ *
+ * Parameters:
+ *	argc	Argument count
+ *	argv	Argument vector
+ * Outputs:
+ *	None.
+ * Returns:
+ *	KDB_CMD_SS[B] for success, a kdb error if failure.
+ * Locking:
+ *	None.
+ * Remarks:
+ *
+ *	Set the arch specific option to trigger a debug trap after the next
+ *	instruction.
+ *
+ *	For 'ssb', set the trace flag in the debug trap handler
+ *	after printing the current insn and return directly without
+ *	invoking the kdb command processor, until a branch instruction
+ *	is encountered.
+ */
+
+static int kdb_ss(int argc, const char **argv)
+{
+	int ssb = 0;
+
+	ssb = (strcmp(argv[0], "ssb") == 0);
+	if (argc != 0)
+		return KDB_ARGCOUNT;
+	/*
+	 * Set trace flag and go.
+	 */
+	KDB_STATE_SET(DOING_SS);
+	if (ssb) {
+		KDB_STATE_SET(DOING_SSB);
+		return KDB_CMD_SSB;
+	}
+	return KDB_CMD_SS;
+}
+
+/* Initialize the breakpoint table and register	breakpoint commands. */
+
+void __init kdb_initbptab(void)
+{
+	int i;
+	kdb_bp_t *bp;
+
+	/*
+	 * First time initialization.
+	 */
+	memset(&kdb_breakpoints, '\0', sizeof(kdb_breakpoints));
+
+	for (i = 0, bp = kdb_breakpoints; i < KDB_MAXBPT; i++, bp++)
+		bp->bp_free = 1;
+
+	kdb_register_repeat("bp", kdb_bp, "[<vaddr>]",
+		"Set/Display breakpoints", 0, KDB_REPEAT_NO_ARGS);
+	kdb_register_repeat("bl", kdb_bp, "[<vaddr>]",
+		"Display breakpoints", 0, KDB_REPEAT_NO_ARGS);
+	if (arch_kgdb_ops.flags & KGDB_HW_BREAKPOINT)
+		kdb_register_repeat("bph", kdb_bp, "[<vaddr>]",
+		"[datar [length]|dataw [length]]   Set hw brk", 0, KDB_REPEAT_NO_ARGS);
+	kdb_register_repeat("bc", kdb_bc, "<bpnum>",
+		"Clear Breakpoint", 0, KDB_REPEAT_NONE);
+	kdb_register_repeat("be", kdb_bc, "<bpnum>",
+		"Enable Breakpoint", 0, KDB_REPEAT_NONE);
+	kdb_register_repeat("bd", kdb_bc, "<bpnum>",
+		"Disable Breakpoint", 0, KDB_REPEAT_NONE);
+
+	kdb_register_repeat("ss", kdb_ss, "",
+		"Single Step", 1, KDB_REPEAT_NO_ARGS);
+	kdb_register_repeat("ssb", kdb_ss, "",
+		"Single step to branch/call", 0, KDB_REPEAT_NO_ARGS);
+	/*
+	 * Architecture dependent initialization.
+	 */
+}
diff --git a/kernel/debug/kdb/kdb_bt.c b/kernel/debug/kdb/kdb_bt.c
new file mode 100644
index 000000000000..483fa4e7aaac
--- /dev/null
+++ b/kernel/debug/kdb/kdb_bt.c
@@ -0,0 +1,208 @@
+/*
+ * Kernel Debugger Architecture Independent Stack Traceback
+ *
+ * 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) 2009 Wind River Systems, Inc.  All Rights Reserved.
+ */
+
+#include <linux/ctype.h>
+#include <linux/string.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/kdb.h>
+#include <linux/nmi.h>
+#include <asm/system.h>
+#include "kdb_private.h"
+
+
+static void kdb_show_stack(struct task_struct *p, void *addr)
+{
+	int old_lvl = console_loglevel;
+	console_loglevel = 15;
+	kdb_set_current_task(p);
+	if (addr) {
+		show_stack((struct task_struct *)p, addr);
+	} else if (kdb_current_regs) {
+#ifdef CONFIG_X86
+		show_stack(p, &kdb_current_regs->sp);
+#else
+		show_stack(p, NULL);
+#endif
+	} else {
+		show_stack(p, NULL);
+	}
+	console_loglevel = old_lvl;
+}
+
+/*
+ * kdb_bt
+ *
+ *	This function implements the 'bt' command.  Print a stack
+ *	traceback.
+ *
+ *	bt [<address-expression>]	(addr-exp is for alternate stacks)
+ *	btp <pid>			Kernel stack for <pid>
+ *	btt <address-expression>	Kernel stack for task structure at
+ *					<address-expression>
+ *	bta [DRSTCZEUIMA]		All useful processes, optionally
+ *					filtered by state
+ *	btc [<cpu>]			The current process on one cpu,
+ *					default is all cpus
+ *
+ *	bt <address-expression> refers to a address on the stack, that location
+ *	is assumed to contain a return address.
+ *
+ *	btt <address-expression> refers to the address of a struct task.
+ *
+ * Inputs:
+ *	argc	argument count
+ *	argv	argument vector
+ * Outputs:
+ *	None.
+ * Returns:
+ *	zero for success, a kdb diagnostic if error
+ * Locking:
+ *	none.
+ * Remarks:
+ *	Backtrack works best when the code uses frame pointers.  But even
+ *	without frame pointers we should get a reasonable trace.
+ *
+ *	mds comes in handy when examining the stack to do a manual traceback or
+ *	to get a starting point for bt <address-expression>.
+ */
+
+static int
+kdb_bt1(struct task_struct *p, unsigned long mask,
+	int argcount, int btaprompt)
+{
+	char buffer[2];
+	if (kdb_getarea(buffer[0], (unsigned long)p) ||
+	    kdb_getarea(buffer[0], (unsigned long)(p+1)-1))
+		return KDB_BADADDR;
+	if (!kdb_task_state(p, mask))
+		return 0;
+	kdb_printf("Stack traceback for pid %d\n", p->pid);
+	kdb_ps1(p);
+	kdb_show_stack(p, NULL);
+	if (btaprompt) {
+		kdb_getstr(buffer, sizeof(buffer),
+			   "Enter <q> to end, <cr> to continue:");
+		if (buffer[0] == 'q') {
+			kdb_printf("\n");
+			return 1;
+		}
+	}
+	touch_nmi_watchdog();
+	return 0;
+}
+
+int
+kdb_bt(int argc, const char **argv)
+{
+	int diag;
+	int argcount = 5;
+	int btaprompt = 1;
+	int nextarg;
+	unsigned long addr;
+	long offset;
+
+	kdbgetintenv("BTARGS", &argcount);	/* Arguments to print */
+	kdbgetintenv("BTAPROMPT", &btaprompt);	/* Prompt after each
+						 * proc in bta */
+
+	if (strcmp(argv[0], "bta") == 0) {
+		struct task_struct *g, *p;
+		unsigned long cpu;
+		unsigned long mask = kdb_task_state_string(argc ? argv[1] :
+							   NULL);
+		if (argc == 0)
+			kdb_ps_suppressed();
+		/* Run the active tasks first */
+		for_each_online_cpu(cpu) {
+			p = kdb_curr_task(cpu);
+			if (kdb_bt1(p, mask, argcount, btaprompt))
+				return 0;
+		}
+		/* Now the inactive tasks */
+		kdb_do_each_thread(g, p) {
+			if (task_curr(p))
+				continue;
+			if (kdb_bt1(p, mask, argcount, btaprompt))
+				return 0;
+		} kdb_while_each_thread(g, p);
+	} else if (strcmp(argv[0], "btp") == 0) {
+		struct task_struct *p;
+		unsigned long pid;
+		if (argc != 1)
+			return KDB_ARGCOUNT;
+		diag = kdbgetularg((char *)argv[1], &pid);
+		if (diag)
+			return diag;
+		p = find_task_by_pid_ns(pid, &init_pid_ns);
+		if (p) {
+			kdb_set_current_task(p);
+			return kdb_bt1(p, ~0UL, argcount, 0);
+		}
+		kdb_printf("No process with pid == %ld found\n", pid);
+		return 0;
+	} else if (strcmp(argv[0], "btt") == 0) {
+		if (argc != 1)
+			return KDB_ARGCOUNT;
+		diag = kdbgetularg((char *)argv[1], &addr);
+		if (diag)
+			return diag;
+		kdb_set_current_task((struct task_struct *)addr);
+		return kdb_bt1((struct task_struct *)addr, ~0UL, argcount, 0);
+	} else if (strcmp(argv[0], "btc") == 0) {
+		unsigned long cpu = ~0;
+		struct task_struct *save_current_task = kdb_current_task;
+		char buf[80];
+		if (argc > 1)
+			return KDB_ARGCOUNT;
+		if (argc == 1) {
+			diag = kdbgetularg((char *)argv[1], &cpu);
+			if (diag)
+				return diag;
+		}
+		/* Recursive use of kdb_parse, do not use argv after
+		 * this point */
+		argv = NULL;
+		if (cpu != ~0) {
+			if (cpu >= num_possible_cpus() || !cpu_online(cpu)) {
+				kdb_printf("no process for cpu %ld\n", cpu);
+				return 0;
+			}
+			sprintf(buf, "btt 0x%p\n", KDB_TSK(cpu));
+			kdb_parse(buf);
+			return 0;
+		}
+		kdb_printf("btc: cpu status: ");
+		kdb_parse("cpu\n");
+		for_each_online_cpu(cpu) {
+			sprintf(buf, "btt 0x%p\n", KDB_TSK(cpu));
+			kdb_parse(buf);
+			touch_nmi_watchdog();
+		}
+		kdb_set_current_task(save_current_task);
+		return 0;
+	} else {
+		if (argc) {
+			nextarg = 1;
+			diag = kdbgetaddrarg(argc, argv, &nextarg, &addr,
+					     &offset, NULL);
+			if (diag)
+				return diag;
+			kdb_show_stack(kdb_current_task, (void *)addr);
+			return 0;
+		} else {
+			return kdb_bt1(kdb_current_task, ~0UL, argcount, 0);
+		}
+	}
+
+	/* NOTREACHED */
+	return 0;
+}
diff --git a/kernel/debug/kdb/kdb_cmds b/kernel/debug/kdb/kdb_cmds
new file mode 100644
index 000000000000..56c88e4db309
--- /dev/null
+++ b/kernel/debug/kdb/kdb_cmds
@@ -0,0 +1,35 @@
+# Initial commands for kdb, alter to suit your needs.
+# These commands are executed in kdb_init() context, no SMP, no
+# processes.  Commands that require process data (including stack or
+# registers) are not reliable this early.  set and bp commands should
+# be safe.  Global breakpoint commands affect each cpu as it is booted.
+
+# Standard debugging information for first level support, just type archkdb
+# or archkdbcpu or archkdbshort at the kdb prompt.
+
+defcmd dumpcommon "" "Common kdb debugging"
+  set BTAPROMPT 0
+  set LINES 10000
+  -summary
+  -cpu
+  -ps
+  -dmesg 600
+  -bt
+endefcmd
+
+defcmd dumpall "" "First line debugging"
+  set BTSYMARG 1
+  set BTARGS 9
+  pid R
+  -dumpcommon
+  -bta
+endefcmd
+
+defcmd dumpcpu "" "Same as dumpall but only tasks on cpus"
+  set BTSYMARG 1
+  set BTARGS 9
+  pid R
+  -dumpcommon
+  -btc
+endefcmd
+
diff --git a/kernel/debug/kdb/kdb_debugger.c b/kernel/debug/kdb/kdb_debugger.c
new file mode 100644
index 000000000000..f024c0c4b8c4
--- /dev/null
+++ b/kernel/debug/kdb/kdb_debugger.c
@@ -0,0 +1,159 @@
+/*
+ * Created by: Jason Wessel <jason.wessel@windriver.com>
+ *
+ * Copyright (c) 2009 Wind River Systems, Inc.  All Rights Reserved.
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/kgdb.h>
+#include <linux/kdb.h>
+#include <linux/kdebug.h>
+#include "kdb_private.h"
+#include "../debug_core.h"
+
+/*
+ * KDB interface to KGDB internals
+ */
+get_char_func kdb_poll_funcs[] = {
+	dbg_io_get_char,
+	NULL,
+};
+
+int kdb_stub(struct kgdb_state *ks)
+{
+	int error = 0;
+	kdb_bp_t *bp;
+	unsigned long addr = kgdb_arch_pc(ks->ex_vector, ks->linux_regs);
+	kdb_reason_t reason = KDB_REASON_OOPS;
+	kdb_dbtrap_t db_result = KDB_DB_NOBPT;
+	int i;
+
+	if (KDB_STATE(REENTRY)) {
+		reason = KDB_REASON_SWITCH;
+		KDB_STATE_CLEAR(REENTRY);
+		addr = instruction_pointer(ks->linux_regs);
+	}
+	ks->pass_exception = 0;
+	if (atomic_read(&kgdb_setting_breakpoint))
+		reason = KDB_REASON_KEYBOARD;
+
+	for (i = 0, bp = kdb_breakpoints; i < KDB_MAXBPT; i++, bp++) {
+		if ((bp->bp_enabled) && (bp->bp_addr == addr)) {
+			reason = KDB_REASON_BREAK;
+			db_result = KDB_DB_BPT;
+			if (addr != instruction_pointer(ks->linux_regs))
+				kgdb_arch_set_pc(ks->linux_regs, addr);
+			break;
+		}
+	}
+	if (reason == KDB_REASON_BREAK || reason == KDB_REASON_SWITCH) {
+		for (i = 0, bp = kdb_breakpoints; i < KDB_MAXBPT; i++, bp++) {
+			if (bp->bp_free)
+				continue;
+			if (bp->bp_addr == addr) {
+				bp->bp_delay = 1;
+				bp->bp_delayed = 1;
+	/*
+	 * SSBPT is set when the kernel debugger must single step a
+	 * task in order to re-establish an instruction breakpoint
+	 * which uses the instruction replacement mechanism.  It is
+	 * cleared by any action that removes the need to single-step
+	 * the breakpoint.
+	 */
+				reason = KDB_REASON_BREAK;
+				db_result = KDB_DB_BPT;
+				KDB_STATE_SET(SSBPT);
+				break;
+			}
+		}
+	}
+
+	if (reason != KDB_REASON_BREAK && ks->ex_vector == 0 &&
+		ks->signo == SIGTRAP) {
+		reason = KDB_REASON_SSTEP;
+		db_result = KDB_DB_BPT;
+	}
+	/* Set initial kdb state variables */
+	KDB_STATE_CLEAR(KGDB_TRANS);
+	kdb_initial_cpu = ks->cpu;
+	kdb_current_task = kgdb_info[ks->cpu].task;
+	kdb_current_regs = kgdb_info[ks->cpu].debuggerinfo;
+	/* Remove any breakpoints as needed by kdb and clear single step */
+	kdb_bp_remove();
+	KDB_STATE_CLEAR(DOING_SS);
+	KDB_STATE_CLEAR(DOING_SSB);
+	/* zero out any offline cpu data */
+	for_each_present_cpu(i) {
+		if (!cpu_online(i)) {
+			kgdb_info[i].debuggerinfo = NULL;
+			kgdb_info[i].task = NULL;
+		}
+	}
+	if (ks->err_code == DIE_OOPS || reason == KDB_REASON_OOPS) {
+		ks->pass_exception = 1;
+		KDB_FLAG_SET(CATASTROPHIC);
+	}
+	kdb_initial_cpu = ks->cpu;
+	if (KDB_STATE(SSBPT) && reason == KDB_REASON_SSTEP) {
+		KDB_STATE_CLEAR(SSBPT);
+		KDB_STATE_CLEAR(DOING_SS);
+	} else {
+		/* Start kdb main loop */
+		error = kdb_main_loop(KDB_REASON_ENTER, reason,
+				      ks->err_code, db_result, ks->linux_regs);
+	}
+	/*
+	 * Upon exit from the kdb main loop setup break points and restart
+	 * the system based on the requested continue state
+	 */
+	kdb_initial_cpu = -1;
+	kdb_current_task = NULL;
+	kdb_current_regs = NULL;
+	kdbnearsym_cleanup();
+	if (error == KDB_CMD_KGDB) {
+		if (KDB_STATE(DOING_KGDB) || KDB_STATE(DOING_KGDB2)) {
+	/*
+	 * This inteface glue which allows kdb to transition in into
+	 * the gdb stub.  In order to do this the '?' or '' gdb serial
+	 * packet response is processed here.  And then control is
+	 * passed to the gdbstub.
+	 */
+			if (KDB_STATE(DOING_KGDB))
+				gdbstub_state(ks, "?");
+			else
+				gdbstub_state(ks, "");
+			KDB_STATE_CLEAR(DOING_KGDB);
+			KDB_STATE_CLEAR(DOING_KGDB2);
+		}
+		return DBG_PASS_EVENT;
+	}
+	kdb_bp_install(ks->linux_regs);
+	dbg_activate_sw_breakpoints();
+	/* Set the exit state to a single step or a continue */
+	if (KDB_STATE(DOING_SS))
+		gdbstub_state(ks, "s");
+	else
+		gdbstub_state(ks, "c");
+
+	KDB_FLAG_CLEAR(CATASTROPHIC);
+
+	/* Invoke arch specific exception handling prior to system resume */
+	kgdb_info[ks->cpu].ret_state = gdbstub_state(ks, "e");
+	if (ks->pass_exception)
+		kgdb_info[ks->cpu].ret_state = 1;
+	if (error == KDB_CMD_CPU) {
+		KDB_STATE_SET(REENTRY);
+		/*
+		 * Force clear the single step bit because kdb emulates this
+		 * differently vs the gdbstub
+		 */
+		kgdb_single_step = 0;
+		dbg_deactivate_sw_breakpoints();
+		return DBG_SWITCH_CPU_EVENT;
+	}
+	return kgdb_info[ks->cpu].ret_state;
+}
+
diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c
new file mode 100644
index 000000000000..9e3cec7a925c
--- /dev/null
+++ b/kernel/debug/kdb/kdb_io.c
@@ -0,0 +1,789 @@
+/*
+ * Kernel Debugger Architecture Independent Console I/O handler
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (c) 1999-2006 Silicon Graphics, Inc.  All Rights Reserved.
+ * Copyright (c) 2009 Wind River Systems, Inc.  All Rights Reserved.
+ */
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/ctype.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/kdev_t.h>
+#include <linux/console.h>
+#include <linux/string.h>
+#include <linux/sched.h>
+#include <linux/smp.h>
+#include <linux/nmi.h>
+#include <linux/delay.h>
+#include <linux/kdb.h>
+#include <linux/kallsyms.h>
+#include "kdb_private.h"
+
+#define CMD_BUFLEN 256
+char kdb_prompt_str[CMD_BUFLEN];
+
+
+static void kgdb_transition_check(char *buffer)
+{
+	int slen = strlen(buffer);
+	if (strncmp(buffer, "$?#3f", slen) != 0 &&
+	    strncmp(buffer, "$qSupported#37", slen) != 0 &&
+	    strncmp(buffer, "+$qSupported#37", slen) != 0) {
+		KDB_STATE_SET(KGDB_TRANS);
+		kdb_printf("%s", buffer);
+	}
+}
+
+static int kdb_read_get_key(char *buffer, size_t bufsize)
+{
+#define ESCAPE_UDELAY 1000
+#define ESCAPE_DELAY (2*1000000/ESCAPE_UDELAY) /* 2 seconds worth of udelays */
+	char escape_data[5];	/* longest vt100 escape sequence is 4 bytes */
+	char *ped = escape_data;
+	int escape_delay = 0;
+	get_char_func *f, *f_escape = NULL;
+	int key;
+
+	for (f = &kdb_poll_funcs[0]; ; ++f) {
+		if (*f == NULL) {
+			/* Reset NMI watchdog once per poll loop */
+			touch_nmi_watchdog();
+			f = &kdb_poll_funcs[0];
+		}
+		if (escape_delay == 2) {
+			*ped = '\0';
+			ped = escape_data;
+			--escape_delay;
+		}
+		if (escape_delay == 1) {
+			key = *ped++;
+			if (!*ped)
+				--escape_delay;
+			break;
+		}
+		key = (*f)();
+		if (key == -1) {
+			if (escape_delay) {
+				udelay(ESCAPE_UDELAY);
+				--escape_delay;
+			}
+			continue;
+		}
+		if (bufsize <= 2) {
+			if (key == '\r')
+				key = '\n';
+			*buffer++ = key;
+			*buffer = '\0';
+			return -1;
+		}
+		if (escape_delay == 0 && key == '\e') {
+			escape_delay = ESCAPE_DELAY;
+			ped = escape_data;
+			f_escape = f;
+		}
+		if (escape_delay) {
+			*ped++ = key;
+			if (f_escape != f) {
+				escape_delay = 2;
+				continue;
+			}
+			if (ped - escape_data == 1) {
+				/* \e */
+				continue;
+			} else if (ped - escape_data == 2) {
+				/* \e<something> */
+				if (key != '[')