Message-Id: <1203108958-1818-7-git-send-email-jason.wessel@windriver.com>
Date:	Fri, 15 Feb 2008 14:55:57 -0600
From:	Jason Wessel <jason.wessel@...driver.com>
To:	mingo@...e.hu
Cc:	linux-kernel@...r.kernel.org,
	Jason Wessel <jason.wessel@...driver.com>
Subject: [PATCH 6/7] kgdb-light-v10: move the kgdb core and arch implementation

Simply relocate the arch specific and kgdb core implementation files
so as to build as a module in a future patch.

Signed-off-by: Jason Wessel <jason.wessel@...driver.com>
---
 arch/x86/kernel/Makefile   |    4 +-
 arch/x86/kernel/kgdb-x86.c |  567 +++++++++++++++
 arch/x86/kernel/kgdb.c     |  567 ---------------
 kernel/Makefile            |    1 -
 kernel/kgdb.c              | 1680 --------------------------------------------
 lib/kgdb.c                 | 1680 ++++++++++++++++++++++++++++++++++++++++++++
 6 files changed, 2250 insertions(+), 2249 deletions(-)
 create mode 100644 arch/x86/kernel/kgdb-x86.c
 delete mode 100644 arch/x86/kernel/kgdb.c
 delete mode 100644 kernel/kgdb.c
 create mode 100644 lib/kgdb.c

diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 4cd39cd..2e733b1 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -58,7 +58,6 @@ obj-$(CONFIG_MODULES)		+= module_$(BITS).o
 obj-$(CONFIG_ACPI_SRAT) 	+= srat_32.o
 obj-$(CONFIG_EFI) 		+= efi.o efi_$(BITS).o efi_stub_$(BITS).o
 obj-$(CONFIG_DOUBLEFAULT) 	+= doublefault_32.o
-obj-$(CONFIG_KGDB)		+= kgdb.o
 obj-$(CONFIG_VM86)		+= vm86_32.o
 obj-$(CONFIG_EARLY_PRINTK)	+= early_printk.o
 
@@ -79,6 +78,9 @@ endif
 obj-$(CONFIG_SCx200)		+= scx200.o
 scx200-y			+= scx200_32.o
 
+kgdb-objs			:= ../../../lib/kgdb.o kgdb-x86.o
+obj-$(CONFIG_KGDB)		+= kgdb.o
+
 ###
 # 64 bit specific files
 ifeq ($(CONFIG_X86_64),y)
diff --git a/arch/x86/kernel/kgdb-x86.c b/arch/x86/kernel/kgdb-x86.c
new file mode 100644
index 0000000..88bfa45
--- /dev/null
+++ b/arch/x86/kernel/kgdb-x86.c
@@ -0,0 +1,567 @@
+/*
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2, or (at your option) any
+ * later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ */
+
+/*
+ * Copyright (C) 2004 Amit S. Kale <amitkale@...syssoft.com>
+ * Copyright (C) 2000-2001 VERITAS Software Corporation.
+ * Copyright (C) 2002 Andi Kleen, SuSE Labs
+ * Copyright (C) 2004 LinSysSoft Technologies Pvt. Ltd.
+ * Copyright (C) 2007 MontaVista Software, Inc.
+ * Copyright (C) 2007-2008 Jason Wessel, Wind River Systems, Inc.
+ */
+/****************************************************************************
+ *  Contributor:     Lake Stevens Instrument Division$
+ *  Written by:      Glenn Engel $
+ *  Updated by:	     Amit Kale<akale@...itas.com>
+ *  Updated by:	     Tom Rini <trini@...nel.crashing.org>
+ *  Updated by:	     Jason Wessel <jason.wessel@...driver.com>
+ *  Modified for 386 by Jim Kingdon, Cygnus Support.
+ *  Origianl kgdb, compatibility with 2.1.xx kernel by
+ *  David Grothe <dave@...m.com>
+ *  Integrated into 2.2.5 kernel by Tigran Aivazian <tigran@....com>
+ *  X86_64 changes from Andi Kleen's patch merged by Jim Houston
+ */
+#include <linux/spinlock.h>
+#include <linux/kdebug.h>
+#include <linux/string.h>
+#include <linux/kernel.h>
+#include <linux/ptrace.h>
+#include <linux/sched.h>
+#include <linux/delay.h>
+#include <linux/kgdb.h>
+#include <linux/init.h>
+#include <linux/smp.h>
+#include <linux/nmi.h>
+
+#include <asm/apicdef.h>
+#include <asm/system.h>
+
+#ifdef CONFIG_X86_32
+# include <mach_ipi.h>
+#else
+# include <asm/mach_apic.h>
+#endif
+
+/*
+ * Put the error code here just in case the user cares:
+ */
+static int gdb_x86errcode;
+
+/*
+ * Likewise, the vector number here (since GDB only gets the signal
+ * number through the usual means, and that's not very specific):
+ */
+static int gdb_x86vector = -1;
+
+/**
+ *	pt_regs_to_gdb_regs - Convert ptrace regs to GDB regs
+ *	@gdb_regs: A pointer to hold the registers in the order GDB wants.
+ *	@regs: The &struct pt_regs of the current process.
+ *
+ *	Convert the pt_regs in @regs into the format for registers that
+ *	GDB expects, stored in @gdb_regs.
+ */
+void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
+{
+	gdb_regs[GDB_AX]	= regs->ax;
+	gdb_regs[GDB_BX]	= regs->bx;
+	gdb_regs[GDB_CX]	= regs->cx;
+	gdb_regs[GDB_DX]	= regs->dx;
+	gdb_regs[GDB_SI]	= regs->si;
+	gdb_regs[GDB_DI]	= regs->di;
+	gdb_regs[GDB_BP]	= regs->bp;
+	gdb_regs[GDB_PS]	= regs->flags;
+	gdb_regs[GDB_PC]	= regs->ip;
+#ifdef CONFIG_X86_32
+	gdb_regs[GDB_DS]	= regs->ds;
+	gdb_regs[GDB_ES]	= regs->es;
+	gdb_regs[GDB_CS]	= regs->cs;
+	gdb_regs[GDB_SS]	= __KERNEL_DS;
+	gdb_regs[GDB_FS]	= 0xFFFF;
+	gdb_regs[GDB_GS]	= 0xFFFF;
+#else
+	gdb_regs[GDB_R8]	= regs->r8;
+	gdb_regs[GDB_R9]	= regs->r9;
+	gdb_regs[GDB_R10]	= regs->r10;
+	gdb_regs[GDB_R11]	= regs->r11;
+	gdb_regs[GDB_R12]	= regs->r12;
+	gdb_regs[GDB_R13]	= regs->r13;
+	gdb_regs[GDB_R14]	= regs->r14;
+	gdb_regs[GDB_R15]	= regs->r15;
+#endif
+	gdb_regs[GDB_SP]	= regs->sp;
+}
+
+/**
+ *	sleeping_thread_to_gdb_regs - Convert ptrace regs to GDB regs
+ *	@gdb_regs: A pointer to hold the registers in the order GDB wants.
+ *	@p: The &struct task_struct of the desired process.
+ *
+ *	Convert the register values of the sleeping process in @p to
+ *	the format that GDB expects.
+ *	This function is called when kgdb does not have access to the
+ *	&struct pt_regs and therefore it should fill the gdb registers
+ *	@gdb_regs with what has	been saved in &struct thread_struct
+ *	thread field during switch_to.
+ */
+void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
+{
+	gdb_regs[GDB_AX]	= 0;
+	gdb_regs[GDB_BX]	= 0;
+	gdb_regs[GDB_CX]	= 0;
+	gdb_regs[GDB_DX]	= 0;
+	gdb_regs[GDB_SI]	= 0;
+	gdb_regs[GDB_DI]	= 0;
+	gdb_regs[GDB_BP]	= *(unsigned long *)p->thread.sp;
+#ifdef CONFIG_X86_32
+	gdb_regs[GDB_DS]	= __KERNEL_DS;
+	gdb_regs[GDB_ES]	= __KERNEL_DS;
+	gdb_regs[GDB_PS]	= 0;
+	gdb_regs[GDB_CS]	= __KERNEL_CS;
+	gdb_regs[GDB_PC]	= p->thread.ip;
+	gdb_regs[GDB_SS]	= __KERNEL_DS;
+	gdb_regs[GDB_FS]	= 0xFFFF;
+	gdb_regs[GDB_GS]	= 0xFFFF;
+#else
+	gdb_regs[GDB_PS]	= *(unsigned long *)(p->thread.sp + 8);
+	gdb_regs[GDB_PC]	= 0;
+	gdb_regs[GDB_R8]	= 0;
+	gdb_regs[GDB_R9]	= 0;
+	gdb_regs[GDB_R10]	= 0;
+	gdb_regs[GDB_R11]	= 0;
+	gdb_regs[GDB_R12]	= 0;
+	gdb_regs[GDB_R13]	= 0;
+	gdb_regs[GDB_R14]	= 0;
+	gdb_regs[GDB_R15]	= 0;
+#endif
+	gdb_regs[GDB_SP]	= p->thread.sp;
+}
+
+/**
+ *	gdb_regs_to_pt_regs - Convert GDB regs to ptrace regs.
+ *	@gdb_regs: A pointer to hold the registers we've received from GDB.
+ *	@regs: A pointer to a &struct pt_regs to hold these values in.
+ *
+ *	Convert the GDB regs in @gdb_regs into the pt_regs, and store them
+ *	in @regs.
+ */
+void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs)
+{
+	regs->ax		= gdb_regs[GDB_AX];
+	regs->bx		= gdb_regs[GDB_BX];
+	regs->cx		= gdb_regs[GDB_CX];
+	regs->dx		= gdb_regs[GDB_DX];
+	regs->si		= gdb_regs[GDB_SI];
+	regs->di		= gdb_regs[GDB_DI];
+	regs->bp		= gdb_regs[GDB_BP];
+	regs->flags		= gdb_regs[GDB_PS];
+	regs->ip		= gdb_regs[GDB_PC];
+#ifdef CONFIG_X86_32
+	regs->ds		= gdb_regs[GDB_DS];
+	regs->es		= gdb_regs[GDB_ES];
+	regs->cs		= gdb_regs[GDB_CS];
+#else
+	regs->r8		= gdb_regs[GDB_R8];
+	regs->r9		= gdb_regs[GDB_R9];
+	regs->r10		= gdb_regs[GDB_R10];
+	regs->r11		= gdb_regs[GDB_R11];
+	regs->r12		= gdb_regs[GDB_R12];
+	regs->r13		= gdb_regs[GDB_R13];
+	regs->r14		= gdb_regs[GDB_R14];
+	regs->r15		= gdb_regs[GDB_R15];
+#endif
+}
+
+static struct hw_breakpoint {
+	unsigned		enabled;
+	unsigned		type;
+	unsigned		len;
+	unsigned long		addr;
+} breakinfo[4];
+
+static void kgdb_correct_hw_break(void)
+{
+	unsigned long dr7;
+	int correctit = 0;
+	int breakbit;
+	int breakno;
+
+	get_debugreg(dr7, 7);
+	for (breakno = 0; breakno < 4; breakno++) {
+		breakbit = 2 << (breakno << 1);
+		if (!(dr7 & breakbit) && breakinfo[breakno].enabled) {
+			correctit = 1;
+			dr7 |= breakbit;
+			dr7 &= ~(0xf0000 << (breakno << 2));
+			dr7 |= ((breakinfo[breakno].len << 2) |
+				 breakinfo[breakno].type) <<
+			       ((breakno << 2) + 16);
+			if (breakno >= 0 && breakno <= 3)
+				set_debugreg(breakinfo[breakno].addr, breakno);
+
+		} else {
+			if ((dr7 & breakbit) && !breakinfo[breakno].enabled) {
+				correctit = 1;
+				dr7 &= ~breakbit;
+				dr7 &= ~(0xf0000 << (breakno << 2));
+			}
+		}
+	}
+	if (correctit)
+		set_debugreg(dr7, 7);
+}
+
+static int
+kgdb_remove_hw_break(unsigned long addr, int len, enum kgdb_bptype bptype)
+{
+	int i;
+
+	for (i = 0; i < 4; i++)
+		if (breakinfo[i].addr == addr && breakinfo[i].enabled)
+			break;
+	if (i == 4)
+		return -1;
+
+	breakinfo[i].enabled = 0;
+
+	return 0;
+}
+
+static void kgdb_remove_all_hw_break(void)
+{
+	int i;
+
+	for (i = 0; i < 4; i++)
+		memset(&breakinfo[i], 0, sizeof(struct hw_breakpoint));
+}
+
+static int
+kgdb_set_hw_break(unsigned long addr, int len, enum kgdb_bptype bptype)
+{
+	unsigned type;
+	int i;
+
+	for (i = 0; i < 4; i++)
+		if (!breakinfo[i].enabled)
+			break;
+	if (i == 4)
+		return -1;
+
+	switch (bptype) {
+	case BP_HARDWARE_BREAKPOINT:
+		type = 0;
+		len  = 1;
+		break;
+	case BP_WRITE_WATCHPOINT:
+		type = 1;
+		break;
+	case BP_ACCESS_WATCHPOINT:
+		type = 3;
+		break;
+	default:
+		return -1;
+	}
+
+	if (len == 1 || len == 2 || len == 4)
+		breakinfo[i].len  = len - 1;
+	else
+		return -1;
+
+	breakinfo[i].enabled = 1;
+	breakinfo[i].addr = addr;
+	breakinfo[i].type = type;
+
+	return 0;
+}
+
+/**
+ *	kgdb_disable_hw_debug - Disable hardware debugging while we in kgdb.
+ *	@regs: Current &struct pt_regs.
+ *
+ *	This function will be called if the particular architecture must
+ *	disable hardware debugging while it is processing gdb packets or
+ *	handling exception.
+ */
+void kgdb_disable_hw_debug(struct pt_regs *regs)
+{
+	/* Disable hardware debugging while we are in kgdb: */
+	set_debugreg(0UL, 7);
+}
+
+/**
+ *	kgdb_post_primary_code - Save error vector/code numbers.
+ *	@regs: Original pt_regs.
+ *	@e_vector: Original error vector.
+ *	@err_code: Original error code.
+ *
+ *	This is needed on architectures which support SMP and KGDB.
+ *	This function is called after all the slave cpus have been put
+ *	to a know spin state and the primary CPU has control over KGDB.
+ */
+void kgdb_post_primary_code(struct pt_regs *regs, int e_vector, int err_code)
+{
+	/* primary processor is completely in the debugger */
+	gdb_x86vector = e_vector;
+	gdb_x86errcode = err_code;
+}
+
+#ifdef CONFIG_SMP
+/**
+ *	kgdb_roundup_cpus - Get other CPUs into a holding pattern
+ *	@flags: Current IRQ state
+ *
+ *	On SMP systems, we need to get the attention of the other CPUs
+ *	and get them be in a known state.  This should do what is needed
+ *	to get the other CPUs to call kgdb_wait(). Note that on some arches,
+ *	the NMI approach is not used for rounding up all the CPUs. For example,
+ *	in case of MIPS, smp_call_function() is used to roundup CPUs. In
+ *	this case, we have to make sure that interrupts are enabled before
+ *	calling smp_call_function(). The argument to this function is
+ *	the flags that will be used when restoring the interrupts. There is
+ *	local_irq_save() call before kgdb_roundup_cpus().
+ *
+ *	On non-SMP systems, this is not called.
+ */
+void kgdb_roundup_cpus(unsigned long flags)
+{
+	send_IPI_allbutself(APIC_DM_NMI);
+}
+#endif
+
+/**
+ *	kgdb_arch_handle_exception - Handle architecture specific GDB packets.
+ *	@vector: The error vector of the exception that happened.
+ *	@signo: The signal number of the exception that happened.
+ *	@err_code: The error code of the exception that happened.
+ *	@remcom_in_buffer: The buffer of the packet we have read.
+ *	@remcom_out_buffer: The buffer of %BUFMAX bytes to write a packet into.
+ *	@regs: The &struct pt_regs of the current process.
+ *
+ *	This function MUST handle the 'c' and 's' command packets,
+ *	as well packets to set / remove a hardware breakpoint, if used.
+ *	If there are additional packets which the hardware needs to handle,
+ *	they are handled here.  The code should return -1 if it wants to
+ *	process more packets, and a %0 or %1 if it wants to exit from the
+ *	kgdb callback.
+ */
+int kgdb_arch_handle_exception(int e_vector, int signo, int err_code,
+			       char *remcomInBuffer, char *remcomOutBuffer,
+			       struct pt_regs *linux_regs)
+{
+	unsigned long addr;
+	unsigned long dr6;
+	char *ptr;
+	int newPC;
+
+	switch (remcomInBuffer[0]) {
+	case 'c':
+	case 's':
+		/* try to read optional parameter, pc unchanged if no parm */
+		ptr = &remcomInBuffer[1];
+		if (kgdb_hex2long(&ptr, &addr))
+			linux_regs->ip = addr;
+		newPC = linux_regs->ip;
+
+		/* clear the trace bit */
+		linux_regs->flags &= ~TF_MASK;
+		atomic_set(&kgdb_cpu_doing_single_step, -1);
+
+		/* set the trace bit if we're stepping */
+		if (remcomInBuffer[0] == 's') {
+			linux_regs->flags |= TF_MASK;
+			kgdb_single_step = 1;
+			if (kgdb_contthread) {
+				atomic_set(&kgdb_cpu_doing_single_step,
+					   raw_smp_processor_id());
+			}
+		}
+
+		get_debugreg(dr6, 6);
+		if (!(dr6 & 0x4000)) {
+			int breakno;
+
+			for (breakno = 0; breakno < 4; breakno++) {
+				if (dr6 & (1 << breakno) &&
+				    breakinfo[breakno].type == 0) {
+					/* Set restore flag: */
+					linux_regs->flags |= X86_EFLAGS_RF;
+					break;
+				}
+			}
+		}
+		set_debugreg(0UL, 6);
+		kgdb_correct_hw_break();
+
+		return 0;
+	}
+
+	/* this means that we do not want to exit from the handler: */
+	return -1;
+}
+
+static inline int
+single_step_cont(struct pt_regs *regs, struct die_args *args)
+{
+	/*
+	 * Single step exception from kernel space to user space so
+	 * eat the exception and continue the process:
+	 */
+	printk(KERN_ERR "KGDB: trap/step from kernel to user space, "
+			"resuming...\n");
+	kgdb_arch_handle_exception(args->trapnr, args->signr,
+				   args->err, "c", "", regs);
+
+	return NOTIFY_STOP;
+}
+
+static int was_in_debug_nmi[NR_CPUS];
+
+static int __kgdb_notify(struct die_args *args, unsigned long cmd)
+{
+	struct pt_regs *regs = args->regs;
+
+	switch (cmd) {
+	case DIE_NMI:
+		if (atomic_read(&kgdb_active) != -1) {
+			/* KGDB CPU roundup */
+			kgdb_nmicallback(raw_smp_processor_id(), regs);
+			was_in_debug_nmi[raw_smp_processor_id()] = 1;
+			touch_nmi_watchdog();
+			return NOTIFY_STOP;
+		}
+		return NOTIFY_DONE;
+
+	case DIE_NMI_IPI:
+		if (atomic_read(&kgdb_active) != -1) {
+			/* KGDB CPU roundup */
+			kgdb_nmicallback(raw_smp_processor_id(), regs);
+			was_in_debug_nmi[raw_smp_processor_id()] = 1;
+			touch_nmi_watchdog();
+		}
+		return NOTIFY_DONE;
+
+	case DIE_NMIUNKNOWN:
+		if (was_in_debug_nmi[raw_smp_processor_id()]) {
+			was_in_debug_nmi[raw_smp_processor_id()] = 0;
+			return NOTIFY_STOP;
+		}
+		return NOTIFY_DONE;
+
+	case DIE_NMIWATCHDOG:
+		if (atomic_read(&kgdb_active) != -1) {
+			/* KGDB CPU roundup: */
+			kgdb_nmicallback(raw_smp_processor_id(), regs);
+			return NOTIFY_STOP;
+		}
+		/* Enter debugger: */
+		break;
+
+	case DIE_DEBUG:
+		if (atomic_read(&kgdb_cpu_doing_single_step) ==
+			raw_smp_processor_id() &&
+			user_mode(regs))
+			return single_step_cont(regs, args);
+		/* fall through */
+	default:
+		if (user_mode(regs))
+			return NOTIFY_DONE;
+	}
+
+	if (kgdb_handle_exception(args->trapnr, args->signr, args->err, regs))
+		return NOTIFY_DONE;
+
+	return NOTIFY_STOP;
+}
+
+static int
+kgdb_notify(struct notifier_block *self, unsigned long cmd, void *ptr)
+{
+	unsigned long flags;
+	int ret;
+
+	local_irq_save(flags);
+	ret = __kgdb_notify(ptr, cmd);
+	local_irq_restore(flags);
+
+	return ret;
+}
+
+static struct notifier_block kgdb_notifier = {
+	.notifier_call	= kgdb_notify,
+
+	/*
+	 * Lowest-prio notifier priority, we want to be notified last:
+	 */
+	.priority	= -INT_MAX,
+};
+
+/**
+ *	kgdb_arch_init - Perform any architecture specific initalization.
+ *
+ *	This function will handle the initalization of any architecture
+ *	specific callbacks.
+ */
+int kgdb_arch_init(void)
+{
+	return register_die_notifier(&kgdb_notifier);
+}
+
+/**
+ *	kgdb_arch_exit - Perform any architecture specific uninitalization.
+ *
+ *	This function will handle the uninitalization of any architecture
+ *	specific callbacks, for dynamic registration and unregistration.
+ */
+void kgdb_arch_exit(void)
+{
+	unregister_die_notifier(&kgdb_notifier);
+}
+
+/**
+ *
+ *	kgdb_skipexception - Bail of of KGDB when we've been triggered.
+ *	@exception: Exception vector number
+ *	@regs: Current &struct pt_regs.
+ *
+ *	On some architectures we need to skip a breakpoint exception when
+ *	it occurs after a breakpoint has been removed.
+ *
+ * Skip an int3 exception when it occurs after a breakpoint has been
+ * removed. Backtrack eip by 1 since the int3 would have caused it to
+ * increment by 1.
+ */
+int kgdb_skipexception(int exception, struct pt_regs *regs)
+{
+	if (exception == 3 && kgdb_isremovedbreak(regs->ip - 1)) {
+		regs->ip -= 1;
+		return 1;
+	}
+	return 0;
+}
+
+unsigned long kgdb_arch_pc(int exception, struct pt_regs *regs)
+{
+	if (exception == 3)
+		return instruction_pointer(regs) - 1;
+	return instruction_pointer(regs);
+}
+
+struct kgdb_arch arch_kgdb_ops = {
+	/* Breakpoint instruction: */
+	.gdb_bpt_instr		= { 0xcc },
+	.flags			= KGDB_HW_BREAKPOINT,
+	.set_hw_breakpoint	= kgdb_set_hw_break,
+	.remove_hw_breakpoint	= kgdb_remove_hw_break,
+	.remove_all_hw_break	= kgdb_remove_all_hw_break,
+	.correct_hw_break	= kgdb_correct_hw_break,
+};
diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c
deleted file mode 100644
index 88bfa45..0000000
--- a/arch/x86/kernel/kgdb.c
+++ /dev/null
@@ -1,567 +0,0 @@
-/*
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License as published by the
- * Free Software Foundation; either version 2, or (at your option) any
- * later version.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * General Public License for more details.
- *
- */
-
-/*
- * Copyright (C) 2004 Amit S. Kale <amitkale@...syssoft.com>
- * Copyright (C) 2000-2001 VERITAS Software Corporation.
- * Copyright (C) 2002 Andi Kleen, SuSE Labs
- * Copyright (C) 2004 LinSysSoft Technologies Pvt. Ltd.
- * Copyright (C) 2007 MontaVista Software, Inc.
- * Copyright (C) 2007-2008 Jason Wessel, Wind River Systems, Inc.
- */
-/****************************************************************************
- *  Contributor:     Lake Stevens Instrument Division$
- *  Written by:      Glenn Engel $
- *  Updated by:	     Amit Kale<akale@...itas.com>
- *  Updated by:	     Tom Rini <trini@...nel.crashing.org>
- *  Updated by:	     Jason Wessel <jason.wessel@...driver.com>
- *  Modified for 386 by Jim Kingdon, Cygnus Support.
- *  Origianl kgdb, compatibility with 2.1.xx kernel by
- *  David Grothe <dave@...m.com>
- *  Integrated into 2.2.5 kernel by Tigran Aivazian <tigran@....com>
- *  X86_64 changes from Andi Kleen's patch merged by Jim Houston
- */
-#include <linux/spinlock.h>
-#include <linux/kdebug.h>
-#include <linux/string.h>
-#include <linux/kernel.h>
-#include <linux/ptrace.h>
-#include <linux/sched.h>
-#include <linux/delay.h>
-#include <linux/kgdb.h>
-#include <linux/init.h>
-#include <linux/smp.h>
-#include <linux/nmi.h>
-
-#include <asm/apicdef.h>
-#include <asm/system.h>
-
-#ifdef CONFIG_X86_32
-# include <mach_ipi.h>
-#else
-# include <asm/mach_apic.h>
-#endif
-
-/*
- * Put the error code here just in case the user cares:
- */
-static int gdb_x86errcode;
-
-/*
- * Likewise, the vector number here (since GDB only gets the signal
- * number through the usual means, and that's not very specific):
- */
-static int gdb_x86vector = -1;
-
-/**
- *	pt_regs_to_gdb_regs - Convert ptrace regs to GDB regs
- *	@gdb_regs: A pointer to hold the registers in the order GDB wants.
- *	@regs: The &struct pt_regs of the current process.
- *
- *	Convert the pt_regs in @regs into the format for registers that
- *	GDB expects, stored in @gdb_regs.
- */
-void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
-{
-	gdb_regs[GDB_AX]	= regs->ax;
-	gdb_regs[GDB_BX]	= regs->bx;
-	gdb_regs[GDB_CX]	= regs->cx;
-	gdb_regs[GDB_DX]	= regs->dx;
-	gdb_regs[GDB_SI]	= regs->si;
-	gdb_regs[GDB_DI]	= regs->di;
-	gdb_regs[GDB_BP]	= regs->bp;
-	gdb_regs[GDB_PS]	= regs->flags;
-	gdb_regs[GDB_PC]	= regs->ip;
-#ifdef CONFIG_X86_32
-	gdb_regs[GDB_DS]	= regs->ds;
-	gdb_regs[GDB_ES]	= regs->es;
-	gdb_regs[GDB_CS]	= regs->cs;
-	gdb_regs[GDB_SS]	= __KERNEL_DS;
-	gdb_regs[GDB_FS]	= 0xFFFF;
-	gdb_regs[GDB_GS]	= 0xFFFF;
-#else
-	gdb_regs[GDB_R8]	= regs->r8;
-	gdb_regs[GDB_R9]	= regs->r9;
-	gdb_regs[GDB_R10]	= regs->r10;
-	gdb_regs[GDB_R11]	= regs->r11;
-	gdb_regs[GDB_R12]	= regs->r12;
-	gdb_regs[GDB_R13]	= regs->r13;
-	gdb_regs[GDB_R14]	= regs->r14;
-	gdb_regs[GDB_R15]	= regs->r15;
-#endif
-	gdb_regs[GDB_SP]	= regs->sp;
-}
-
-/**
- *	sleeping_thread_to_gdb_regs - Convert ptrace regs to GDB regs
- *	@gdb_regs: A pointer to hold the registers in the order GDB wants.
- *	@p: The &struct task_struct of the desired process.
- *
- *	Convert the register values of the sleeping process in @p to
- *	the format that GDB expects.
- *	This function is called when kgdb does not have access to the
- *	&struct pt_regs and therefore it should fill the gdb registers
- *	@gdb_regs with what has	been saved in &struct thread_struct
- *	thread field during switch_to.
- */
-void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
-{
-	gdb_regs[GDB_AX]	= 0;
-	gdb_regs[GDB_BX]	= 0;
-	gdb_regs[GDB_CX]	= 0;
-	gdb_regs[GDB_DX]	= 0;
-	gdb_regs[GDB_SI]	= 0;
-	gdb_regs[GDB_DI]	= 0;
-	gdb_regs[GDB_BP]	= *(unsigned long *)p->thread.sp;
-#ifdef CONFIG_X86_32
-	gdb_regs[GDB_DS]	= __KERNEL_DS;
-	gdb_regs[GDB_ES]	= __KERNEL_DS;
-	gdb_regs[GDB_PS]	= 0;
-	gdb_regs[GDB_CS]	= __KERNEL_CS;
-	gdb_regs[GDB_PC]	= p->thread.ip;
-	gdb_regs[GDB_SS]	= __KERNEL_DS;
-	gdb_regs[GDB_FS]	= 0xFFFF;
-	gdb_regs[GDB_GS]	= 0xFFFF;
-#else
-	gdb_regs[GDB_PS]	= *(unsigned long *)(p->thread.sp + 8);
-	gdb_regs[GDB_PC]	= 0;
-	gdb_regs[GDB_R8]	= 0;
-	gdb_regs[GDB_R9]	= 0;
-	gdb_regs[GDB_R10]	= 0;
-	gdb_regs[GDB_R11]	= 0;
-	gdb_regs[GDB_R12]	= 0;
-	gdb_regs[GDB_R13]	= 0;
-	gdb_regs[GDB_R14]	= 0;
-	gdb_regs[GDB_R15]	= 0;
-#endif
-	gdb_regs[GDB_SP]	= p->thread.sp;
-}
-
-/**
- *	gdb_regs_to_pt_regs - Convert GDB regs to ptrace regs.
- *	@gdb_regs: A pointer to hold the registers we've received from GDB.
- *	@regs: A pointer to a &struct pt_regs to hold these values in.
- *
- *	Convert the GDB regs in @gdb_regs into the pt_regs, and store them
- *	in @regs.
- */
-void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs)
-{
-	regs->ax		= gdb_regs[GDB_AX];
-	regs->bx		= gdb_regs[GDB_BX];
-	regs->cx		= gdb_regs[GDB_CX];
-	regs->dx		= gdb_regs[GDB_DX];
-	regs->si		= gdb_regs[GDB_SI];
-	regs->di		= gdb_regs[GDB_DI];
-	regs->bp		= gdb_regs[GDB_BP];
-	regs->flags		= gdb_regs[GDB_PS];
-	regs->ip		= gdb_regs[GDB_PC];
-#ifdef CONFIG_X86_32
-	regs->ds		= gdb_regs[GDB_DS];
-	regs->es		= gdb_regs[GDB_ES];
-	regs->cs		= gdb_regs[GDB_CS];
-#else
-	regs->r8		= gdb_regs[GDB_R8];
-	regs->r9		= gdb_regs[GDB_R9];
-	regs->r10		= gdb_regs[GDB_R10];
-	regs->r11		= gdb_regs[GDB_R11];
-	regs->r12		= gdb_regs[GDB_R12];
-	regs->r13		= gdb_regs[GDB_R13];
-	regs->r14		= gdb_regs[GDB_R14];
-	regs->r15		= gdb_regs[GDB_R15];
-#endif
-}
-
-static struct hw_breakpoint {
-	unsigned		enabled;
-	unsigned		type;
-	unsigned		len;
-	unsigned long		addr;
-} breakinfo[4];
-
-static void kgdb_correct_hw_break(void)
-{
-	unsigned long dr7;
-	int correctit = 0;
-	int breakbit;
-	int breakno;
-
-	get_debugreg(dr7, 7);
-	for (breakno = 0; breakno < 4; breakno++) {
-		breakbit = 2 << (breakno << 1);
-		if (!(dr7 & breakbit) && breakinfo[breakno].enabled) {
-			correctit = 1;
-			dr7 |= breakbit;
-			dr7 &= ~(0xf0000 << (breakno << 2));
-			dr7 |= ((breakinfo[breakno].len << 2) |
-				 breakinfo[breakno].type) <<
-			       ((breakno << 2) + 16);
-			if (breakno >= 0 && breakno <= 3)
-				set_debugreg(breakinfo[breakno].addr, breakno);
-
-		} else {
-			if ((dr7 & breakbit) && !breakinfo[breakno].enabled) {
-				correctit = 1;
-				dr7 &= ~breakbit;
-				dr7 &= ~(0xf0000 << (breakno << 2));
-			}
-		}
-	}
-	if (correctit)
-		set_debugreg(dr7, 7);
-}
-
-static int
-kgdb_remove_hw_break(unsigned long addr, int len, enum kgdb_bptype bptype)
-{
-	int i;
-
-	for (i = 0; i < 4; i++)
-		if (breakinfo[i].addr == addr && breakinfo[i].enabled)
-			break;
-	if (i == 4)
-		return -1;
-
-	breakinfo[i].enabled = 0;
-
-	return 0;
-}
-
-static void kgdb_remove_all_hw_break(void)
-{
-	int i;
-
-	for (i = 0; i < 4; i++)
-		memset(&breakinfo[i], 0, sizeof(struct hw_breakpoint));
-}
-
-static int
-kgdb_set_hw_break(unsigned long addr, int len, enum kgdb_bptype bptype)
-{
-	unsigned type;
-	int i;
-
-	for (i = 0; i < 4; i++)
-		if (!breakinfo[i].enabled)
-			break;
-	if (i == 4)
-		return -1;
-
-	switch (bptype) {
-	case BP_HARDWARE_BREAKPOINT:
-		type = 0;
-		len  = 1;
-		break;
-	case BP_WRITE_WATCHPOINT:
-		type = 1;
-		break;
-	case BP_ACCESS_WATCHPOINT:
-		type = 3;
-		break;
-	default:
-		return -1;
-	}
-
-	if (len == 1 || len == 2 || len == 4)
-		breakinfo[i].len  = len - 1;
-	else
-		return -1;
-
-	breakinfo[i].enabled = 1;
-	breakinfo[i].addr = addr;
-	breakinfo[i].type = type;
-
-	return 0;
-}
-
-/**
- *	kgdb_disable_hw_debug - Disable hardware debugging while we in kgdb.
- *	@regs: Current &struct pt_regs.
- *
- *	This function will be called if the particular architecture must
- *	disable hardware debugging while it is processing gdb packets or
- *	handling exception.
- */
-void kgdb_disable_hw_debug(struct pt_regs *regs)
-{
-	/* Disable hardware debugging while we are in kgdb: */
-	set_debugreg(0UL, 7);
-}
-
-/**
- *	kgdb_post_primary_code - Save error vector/code numbers.
- *	@regs: Original pt_regs.
- *	@e_vector: Original error vector.
- *	@err_code: Original error code.
- *
- *	This is needed on architectures which support SMP and KGDB.
- *	This function is called after all the slave cpus have been put
- *	to a know spin state and the primary CPU has control over KGDB.
- */
-void kgdb_post_primary_code(struct pt_regs *regs, int e_vector, int err_code)
-{
-	/* primary processor is completely in the debugger */
-	gdb_x86vector = e_vector;
-	gdb_x86errcode = err_code;
-}
-
-#ifdef CONFIG_SMP
-/**
- *	kgdb_roundup_cpus - Get other CPUs into a holding pattern
- *	@flags: Current IRQ state
- *
- *	On SMP systems, we need to get the attention of the other CPUs
- *	and get them be in a known state.  This should do what is needed
- *	to get the other CPUs to call kgdb_wait(). Note that on some arches,
- *	the NMI approach is not used for rounding up all the CPUs. For example,
- *	in case of MIPS, smp_call_function() is used to roundup CPUs. In
- *	this case, we have to make sure that interrupts are enabled before
- *	calling smp_call_function(). The argument to this function is
- *	the flags that will be used when restoring the interrupts. There is
- *	local_irq_save() call before kgdb_roundup_cpus().
- *
- *	On non-SMP systems, this is not called.
- */
-void kgdb_roundup_cpus(unsigned long flags)
-{
-	send_IPI_allbutself(APIC_DM_NMI);
-}
-#endif
-
-/**
- *	kgdb_arch_handle_exception - Handle architecture specific GDB packets.
- *	@vector: The error vector of the exception that happened.
- *	@signo: The signal number of the exception that happened.
- *	@err_code: The error code of the exception that happened.
- *	@remcom_in_buffer: The buffer of the packet we have read.
- *	@remcom_out_buffer: The buffer of %BUFMAX bytes to write a packet into.
- *	@regs: The &struct pt_regs of the current process.
- *
- *	This function MUST handle the 'c' and 's' command packets,
- *	as well packets to set / remove a hardware breakpoint, if used.
- *	If there are additional packets which the hardware needs to handle,
- *	they are handled here.  The code should return -1 if it wants to
- *	process more packets, and a %0 or %1 if it wants to exit from the
- *	kgdb callback.
- */
-int kgdb_arch_handle_exception(int e_vector, int signo, int err_code,
-			       char *remcomInBuffer, char *remcomOutBuffer,
-			       struct pt_regs *linux_regs)
-{
-	unsigned long addr;
-	unsigned long dr6;
-	char *ptr;
-	int newPC;
-
-	switch (remcomInBuffer[0]) {
-	case 'c':
-	case 's':
-		/* try to read optional parameter, pc unchanged if no parm */
-		ptr = &remcomInBuffer[1];
-		if (kgdb_hex2long(&ptr, &addr))
-			linux_regs->ip = addr;
-		newPC = linux_regs->ip;
-
-		/* clear the trace bit */
-		linux_regs->flags &= ~TF_MASK;
-		atomic_set(&kgdb_cpu_doing_single_step, -1);
-
-		/* set the trace bit if we're stepping */
-		if (remcomInBuffer[0] == 's') {
-			linux_regs->flags |= TF_MASK;
-			kgdb_single_step = 1;
-			if (kgdb_contthread) {
-				atomic_set(&kgdb_cpu_doing_single_step,
-					   raw_smp_processor_id());
-			}
-		}
-
-		get_debugreg(dr6, 6);
-		if (!(dr6 & 0x4000)) {
-			int breakno;
-
-			for (breakno = 0; breakno < 4; breakno++) {
-				if (dr6 & (1 << breakno) &&
-				    breakinfo[breakno].type == 0) {
-					/* Set restore flag: */
-					linux_regs->flags |= X86_EFLAGS_RF;
-					break;
-				}
-			}
-		}
-		set_debugreg(0UL, 6);
-		kgdb_correct_hw_break();
-
-		return 0;
-	}
-
-	/* this means that we do not want to exit from the handler: */
-	return -1;
-}
-
-static inline int
-single_step_cont(struct pt_regs *regs, struct die_args *args)
-{
-	/*
-	 * Single step exception from kernel space to user space so
-	 * eat the exception and continue the process:
-	 */
-	printk(KERN_ERR "KGDB: trap/step from kernel to user space, "
-			"resuming...\n");
-	kgdb_arch_handle_exception(args->trapnr, args->signr,
-				   args->err, "c", "", regs);
-
-	return NOTIFY_STOP;
-}
-
-static int was_in_debug_nmi[NR_CPUS];
-
-static int __kgdb_notify(struct die_args *args, unsigned long cmd)
-{
-	struct pt_regs *regs = args->regs;
-
-	switch (cmd) {
-	case DIE_NMI:
-		if (atomic_read(&kgdb_active) != -1) {
-			/* KGDB CPU roundup */
-			kgdb_nmicallback(raw_smp_processor_id(), regs);
-			was_in_debug_nmi[raw_smp_processor_id()] = 1;
-			touch_nmi_watchdog();
-			return NOTIFY_STOP;
-		}
-		return NOTIFY_DONE;
-
-	case DIE_NMI_IPI:
-		if (atomic_read(&kgdb_active) != -1) {
-			/* KGDB CPU roundup */
-			kgdb_nmicallback(raw_smp_processor_id(), regs);
-			was_in_debug_nmi[raw_smp_processor_id()] = 1;
-			touch_nmi_watchdog();
-		}
-		return NOTIFY_DONE;
-
-	case DIE_NMIUNKNOWN:
-		if (was_in_debug_nmi[raw_smp_processor_id()]) {
-			was_in_debug_nmi[raw_smp_processor_id()] = 0;
-			return NOTIFY_STOP;
-		}
-		return NOTIFY_DONE;
-
-	case DIE_NMIWATCHDOG:
-		if (atomic_read(&kgdb_active) != -1) {
-			/* KGDB CPU roundup: */
-			kgdb_nmicallback(raw_smp_processor_id(), regs);
-			return NOTIFY_STOP;
-		}
-		/* Enter debugger: */
-		break;
-
-	case DIE_DEBUG:
-		if (atomic_read(&kgdb_cpu_doing_single_step) ==
-			raw_smp_processor_id() &&
-			user_mode(regs))
-			return single_step_cont(regs, args);
-		/* fall through */
-	default:
-		if (user_mode(regs))
-			return NOTIFY_DONE;
-	}
-
-	if (kgdb_handle_exception(args->trapnr, args->signr, args->err, regs))
-		return NOTIFY_DONE;
-
-	return NOTIFY_STOP;
-}
-
-static int
-kgdb_notify(struct notifier_block *self, unsigned long cmd, void *ptr)
-{
-	unsigned long flags;
-	int ret;
-
-	local_irq_save(flags);
-	ret = __kgdb_notify(ptr, cmd);
-	local_irq_restore(flags);
-
-	return ret;
-}
-
-static struct notifier_block kgdb_notifier = {
-	.notifier_call	= kgdb_notify,
-
-	/*
-	 * Lowest-prio notifier priority, we want to be notified last:
-	 */
-	.priority	= -INT_MAX,
-};
-
-/**
- *	kgdb_arch_init - Perform any architecture specific initalization.
- *
- *	This function will handle the initalization of any architecture
- *	specific callbacks.
- */
-int kgdb_arch_init(void)
-{
-	return register_die_notifier(&kgdb_notifier);
-}
-
-/**
- *	kgdb_arch_exit - Perform any architecture specific uninitalization.
- *
- *	This function will handle the uninitalization of any architecture
- *	specific callbacks, for dynamic registration and unregistration.
- */
-void kgdb_arch_exit(void)
-{
-	unregister_die_notifier(&kgdb_notifier);
-}
-
-/**
- *
- *	kgdb_skipexception - Bail of of KGDB when we've been triggered.
- *	@exception: Exception vector number
- *	@regs: Current &struct pt_regs.
- *
- *	On some architectures we need to skip a breakpoint exception when
- *	it occurs after a breakpoint has been removed.
- *
- * Skip an int3 exception when it occurs after a breakpoint has been
- * removed. Backtrack eip by 1 since the int3 would have caused it to
- * increment by 1.
- */
-int kgdb_skipexception(int exception, struct pt_regs *regs)
-{
-	if (exception == 3 && kgdb_isremovedbreak(regs->ip - 1)) {
-		regs->ip -= 1;
-		return 1;
-	}
-	return 0;
-}
-
-unsigned long kgdb_arch_pc(int exception, struct pt_regs *regs)
-{
-	if (exception == 3)
-		return instruction_pointer(regs) - 1;
-	return instruction_pointer(regs);
-}
-
-struct kgdb_arch arch_kgdb_ops = {
-	/* Breakpoint instruction: */
-	.gdb_bpt_instr		= { 0xcc },
-	.flags			= KGDB_HW_BREAKPOINT,
-	.set_hw_breakpoint	= kgdb_set_hw_break,
-	.remove_hw_breakpoint	= kgdb_remove_hw_break,
-	.remove_all_hw_break	= kgdb_remove_all_hw_break,
-	.correct_hw_break	= kgdb_correct_hw_break,
-};
diff --git a/kernel/Makefile b/kernel/Makefile
index 05c8003..6c584c5 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -53,7 +53,6 @@ obj-$(CONFIG_AUDIT) += audit.o auditfilter.o
 obj-$(CONFIG_AUDITSYSCALL) += auditsc.o
 obj-$(CONFIG_AUDIT_TREE) += audit_tree.o
 obj-$(CONFIG_KPROBES) += kprobes.o
-obj-$(CONFIG_KGDB) += kgdb.o
 obj-$(CONFIG_DETECT_SOFTLOCKUP) += softlockup.o
 obj-$(CONFIG_GENERIC_HARDIRQS) += irq/
 obj-$(CONFIG_SECCOMP) += seccomp.o
diff --git a/kernel/kgdb.c b/kernel/kgdb.c
deleted file mode 100644
index a453764..0000000
--- a/kernel/kgdb.c
+++ /dev/null
@@ -1,1680 +0,0 @@
-/*
- * KGDB stub.
- *
- * Maintainer: Jason Wessel <jason.wessel@...driver.com>
- *
- * Copyright (C) 2000-2001 VERITAS Software Corporation.
- * Copyright (C) 2002-2004 Timesys Corporation
- * Copyright (C) 2003-2004 Amit S. Kale <amitkale@...syssoft.com>
- * Copyright (C) 2004 Pavel Machek <pavel@...e.cz>
- * Copyright (C) 2004-2006 Tom Rini <trini@...nel.crashing.org>
- * Copyright (C) 2004-2006 LinSysSoft Technologies Pvt. Ltd.
- * Copyright (C) 2005-2008 Wind River Systems, Inc.
- * Copyright (C) 2007 MontaVista Software, Inc.
- * Copyright (C) 2008 Red Hat, Inc., Ingo Molnar <mingo@...hat.com>
- *
- * Contributors at various stages not listed above:
- *  Jason Wessel ( jason.wessel@...driver.com )
- *  George Anzinger <george@...sta.com>
- *  Anurekh Saxena (anurekh.saxena@...esys.com)
- *  Lake Stevens Instrument Division (Glenn Engel)
- *  Jim Kingdon, Cygnus Support.
- *
- * Original KGDB stub: David Grothe <dave@...m.com>,
- * Tigran Aivazian <tigran@....com>
- *
- * 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/pid_namespace.h>
-#include <linux/clocksource.h>
-#include <linux/interrupt.h>
-#include <linux/spinlock.h>
-#include <linux/console.h>
-#include <linux/threads.h>
-#include <linux/uaccess.h>
-#include <linux/kernel.h>
-#include <linux/module.h>
-#include <linux/ptrace.h>
-#include <linux/reboot.h>
-#include <linux/string.h>
-#include <linux/delay.h>
-#include <linux/sched.h>
-#include <linux/sysrq.h>
-#include <linux/init.h>
-#include <linux/kgdb.h>
-#include <linux/pid.h>
-#include <linux/smp.h>
-#include <linux/mm.h>
-
-#include <asm/cacheflush.h>
-#include <asm/byteorder.h>
-#include <asm/atomic.h>
-#include <asm/system.h>
-
-static int kgdb_break_asap;
-
-struct kgdb_state {
-	int			ex_vector;
-	int			signo;
-	int			err_code;
-	int			cpu;
-	int			pass_exception;
-	long			threadid;
-	long			kgdb_usethreadid;
-	struct pt_regs		*linux_regs;
-};
-
-static struct debuggerinfo_struct {
-	void			*debuggerinfo;
-	struct task_struct	*task;
-} kgdb_info[NR_CPUS];
-
-/**
- * kgdb_connected - Is a host GDB connected to us?
- */
-int				kgdb_connected;
-EXPORT_SYMBOL_GPL(kgdb_connected);
-
-/* All the KGDB handlers are installed */
-static int			kgdb_io_module_registered;
-
-/* Guard for recursive entry */
-static int			exception_level;
-
-static struct kgdb_io		*kgdb_io_ops;
-static DEFINE_SPINLOCK(kgdb_registration_lock);
-
-/* kgdb console driver is loaded */
-static int kgdb_con_registered;
-/* determine if kgdb console output should be used */
-static int kgdb_use_con;
-
-static int __init opt_kgdb_con(char *str)
-{
-	kgdb_use_con = 1;
-	return 0;
-}
-
-early_param("kgdbcon", opt_kgdb_con);
-
-module_param(kgdb_use_con, int, 0644);
-
-/*
- * Holds information about breakpoints in a kernel. These breakpoints are
- * added and removed by gdb.
- */
-static struct kgdb_bkpt		kgdb_break[KGDB_MAX_BREAKPOINTS] = {
-	[0 ... KGDB_MAX_BREAKPOINTS-1] = { .state = BP_UNDEFINED }
-};
-
-/*
- * The CPU# of the active CPU, or -1 if none:
- */
-atomic_t			kgdb_active = ATOMIC_INIT(-1);
-
-/*
- * We use NR_CPUs not PERCPU, in case kgdb is used to debug early
- * bootup code (which might not have percpu set up yet):
- */
-static atomic_t			passive_cpu_wait[NR_CPUS];
-static atomic_t			cpu_in_kgdb[NR_CPUS];
-atomic_t			kgdb_setting_breakpoint;
-
-struct task_struct		*kgdb_usethread;
-struct task_struct		*kgdb_contthread;
-
-int				kgdb_single_step;
-
-/* Our I/O buffers. */
-static char			remcom_in_buffer[BUFMAX];
-static char			remcom_out_buffer[BUFMAX];
-
-/* Storage for the registers, in GDB format. */
-static unsigned long		gdb_regs[(NUMREGBYTES +
-					sizeof(unsigned long) - 1) /
-					sizeof(unsigned long)];
-
-/* to keep track of the CPU which is doing the single stepping*/
-atomic_t			kgdb_cpu_doing_single_step = ATOMIC_INIT(-1);
-
-/*
- * Finally, some KGDB code :-)
- */
-
-/*
- * Weak aliases for breakpoint management,
- * can be overriden by architectures when needed:
- */
-int __weak kgdb_validate_break_address(unsigned long addr)
-{
-	char tmp_variable[BREAK_INSTR_SIZE];
-
-	return probe_kernel_read(tmp_variable, (char *)addr, BREAK_INSTR_SIZE);
-}
-
-int __weak kgdb_arch_set_breakpoint(unsigned long addr, char *saved_instr)
-{
-	int err;
-
-	err = probe_kernel_read(saved_instr, (char *)addr, BREAK_INSTR_SIZE);
-	if (err)
-		return err;
-
-	return probe_kernel_write((char *)addr, arch_kgdb_ops.gdb_bpt_instr,
-				  BREAK_INSTR_SIZE);
-}
-
-int __weak kgdb_arch_remove_breakpoint(unsigned long addr, char *bundle)
-{
-	return probe_kernel_write((char *)addr,
-				  (char *)bundle, BREAK_INSTR_SIZE);
-}
-
-unsigned long __weak kgdb_arch_pc(int exception, struct pt_regs *regs)
-{
-	return instruction_pointer(regs);
-}
-
-int __weak kgdb_arch_init(void)
-{
-	return 0;
-}
-
-/**
- *	kgdb_disable_hw_debug - Disable hardware debugging while we in kgdb.
- *	@regs: Current &struct pt_regs.
- *
- *	This function will be called if the particular architecture must
- *	disable hardware debugging while it is processing gdb packets or
- *	handling exception.
- */
-void __weak kgdb_disable_hw_debug(struct pt_regs *regs)
-{
-}
-
-/*
- * GDB remote protocol parser:
- */
-
-static const char	hexchars[] = "0123456789abcdef";
-
-static int hex(char ch)
-{
-	if ((ch >= 'a') && (ch <= 'f'))
-		return ch - 'a' + 10;
-	if ((ch >= '0') && (ch <= '9'))
-		return ch - '0';
-	if ((ch >= 'A') && (ch <= 'F'))
-		return ch - 'A' + 10;
-	return -1;
-}
-
-/* scan for the sequence $<data>#<checksum> */
-static void get_packet(char *buffer)
-{
-	unsigned char checksum;
-	unsigned char xmitcsum;
-	int count;
-	char ch;
-
-	do {
-		/*
-		 * Spin and wait around for the start character, ignore all
-		 * other characters:
-		 */
-		while ((ch = (kgdb_io_ops->read_char())) != '$')
-			/* nothing */;
-
-		kgdb_connected = 1;
-		checksum = 0;
-		xmitcsum = -1;
-
-		count = 0;
-
-		/*
-		 * now, read until a # or end of buffer is found:
-		 */
-		while (count < (BUFMAX - 1)) {
-			ch = kgdb_io_ops->read_char();
-			if (ch == '#')
-				break;
-			checksum = checksum + ch;
-			buffer[count] = ch;
-			count = count + 1;
-		}
-		buffer[count] = 0;
-
-		if (ch == '#') {
-			xmitcsum = hex(kgdb_io_ops->read_char()) << 4;
-			xmitcsum += hex(kgdb_io_ops->read_char());
-
-			if (checksum != xmitcsum)
-				/* failed checksum */
-				kgdb_io_ops->write_char('-');
-			else
-				/* successful transfer */
-				kgdb_io_ops->write_char('+');
-			if (kgdb_io_ops->flush)
-				kgdb_io_ops->flush();
-		}
-	} while (checksum != xmitcsum);
-}
-
-/*
- * Send the packet in buffer.
- * Check for gdb connection if asked for.
- */
-static void put_packet(char *buffer)
-{
-	unsigned char checksum;
-	int count;
-	char ch;
-
-	/*
-	 * $<packet info>#<checksum>.
-	 */
-	while (1) {
-		kgdb_io_ops->write_char('$');
-		checksum = 0;
-		count = 0;
-
-		while ((ch = buffer[count])) {
-			kgdb_io_ops->write_char(ch);
-			checksum += ch;
-			count++;
-		}
-
-		kgdb_io_ops->write_char('#');
-		kgdb_io_ops->write_char(hexchars[checksum >> 4]);
-		kgdb_io_ops->write_char(hexchars[checksum & 0xf]);
-		if (kgdb_io_ops->flush)
-			kgdb_io_ops->flush();
-
-		/* Now see what we get in reply. */
-		ch = kgdb_io_ops->read_char();
-
-		if (ch == 3)
-			ch = kgdb_io_ops->read_char();
-
-		/* If we get an ACK, we are done. */
-		if (ch == '+')
-			return;
-
-		/*
-		 * If we get the start of another packet, this means
-		 * that GDB is attempting to reconnect.  We will NAK
-		 * the packet being sent, and stop trying to send this
-		 * packet.
-		 */
-		if (ch == '$') {
-			kgdb_io_ops->write_char('-');
-			if (kgdb_io_ops->flush)
-				kgdb_io_ops->flush();
-			return;
-		}
-	}
-}
-
-static char *pack_hex_byte(char *pkt, u8 byte)
-{
-	*pkt++ = hexchars[byte >> 4];
-	*pkt++ = hexchars[byte & 0xf];
-
-	return pkt;
-}
-
-/*
- * Convert the memory pointed to by mem into hex, placing result in buf.
- * Return a pointer to the last char put in buf (null). May return an error.
- */
-int kgdb_mem2hex(char *mem, char *buf, int count)
-{
-	char *tmp;
-	int err;
-
-	/*
-	 * We use the upper half of buf as an intermediate buffer for the
-	 * raw memory copy.  Hex conversion will work against this one.
-	 */
-	tmp = buf + count;
-
-	err = probe_kernel_read(tmp, mem, count);
-	if (!err) {
-		while (count > 0) {
-			buf = pack_hex_byte(buf, *tmp);
-			tmp++;
-			count--;
-		}
-
-		*buf = 0;
-	}
-
-	return err;
-}
-
-/*
- * Copy the binary array pointed to by buf into mem.  Fix $, #, and
- * 0x7d escaped with 0x7d.  Return a pointer to the character after
- * the last byte written.
- */
-static int kgdb_ebin2mem(char *buf, char *mem, int count)
-{
-	int err = 0;
-	char c;
-
-	while (count-- > 0) {
-		c = *buf++;
-		if (c == 0x7d)
-			c = *buf++ ^ 0x20;
-
-		err = probe_kernel_write(mem, &c, 1);
-		if (err)
-			break;
-
-		mem++;
-	}
-
-	return err;
-}
-
-/*
- * Convert the hex array pointed to by buf into binary to be placed in mem.
- * Return a pointer to the character AFTER the last byte written.
- * May return an error.
- */
-int kgdb_hex2mem(char *buf, char *mem, int count)
-{
-	char *tmp_raw;
-	char *tmp_hex;
-
-	/*
-	 * We use the upper half of buf as an intermediate buffer for the
-	 * raw memory that is converted from hex.
-	 */
-	tmp_raw = buf + count * 2;
-
-	tmp_hex = tmp_raw - 1;
-	while (tmp_hex >= buf) {
-		tmp_raw--;
-		*tmp_raw = hex(*tmp_hex--);
-		*tmp_raw |= hex(*tmp_hex--) << 4;
-	}
-
-	return probe_kernel_write(mem, tmp_raw, count);
-}
-
-/*
- * While we find nice hex chars, build a long_val.
- * Return number of chars processed.
- */
-int kgdb_hex2long(char **ptr, long *long_val)
-{
-	int hex_val;
-	int num = 0;
-
-	*long_val = 0;
-
-	while (**ptr) {
-		hex_val = hex(**ptr);
-		if (hex_val < 0)
-			break;
-
-		*long_val = (*long_val << 4) | hex_val;
-		num++;
-		(*ptr)++;
-	}
-
-	return num;
-}
-
-/* Write memory due to an 'M' or 'X' packet. */
-static int write_mem_msg(int binary)
-{
-	char *ptr = &remcom_in_buffer[1];
-	unsigned long addr;
-	unsigned long length;
-	int err;
-
-	if (kgdb_hex2long(&ptr, &addr) > 0 && *(ptr++) == ',' &&
-	    kgdb_hex2long(&ptr, &length) > 0 && *(ptr++) == ':') {
-		if (binary)
-			err = kgdb_ebin2mem(ptr, (char *)addr, length);
-		else
-			err = kgdb_hex2mem(ptr, (char *)addr, length);
-		if (err)
-			return err;
-		if (CACHE_FLUSH_IS_SAFE)
-			flush_icache_range(addr, addr + length + 1);
-		return 0;
-	}
-
-	return -EINVAL;
-}
-
-static void error_packet(char *pkt, int error)
-{
-	error = -error;
-	pkt[0] = 'E';
-	pkt[1] = hexchars[(error / 10)];
-	pkt[2] = hexchars[(error % 10)];
-	pkt[3] = '\0';
-}
-
-/*
- * Thread ID accessors. We represent a flat TID space to GDB, where
- * the per CPU idle threads (which under Linux all have PID 0) are
- * remapped to negative TIDs.
- */
-
-#define BUF_THREAD_ID_SIZE	16
-
-static char *pack_threadid(char *pkt, unsigned char *id)
-{
-	char *limit;
-
-	limit = pkt + BUF_THREAD_ID_SIZE;
-	while (pkt < limit)
-		pkt = pack_hex_byte(pkt, *id++);
-
-	return pkt;
-}
-
-static void int_to_threadref(unsigned char *id, int value)
-{
-	unsigned char *scan;
-	int i = 4;
-
-	scan = (unsigned char *)id;
-	while (i--)
-		*scan++ = 0;
-	*scan++ = (value >> 24) & 0xff;
-	*scan++ = (value >> 16) & 0xff;
-	*scan++ = (value >> 8) & 0xff;
-	*scan++ = (value & 0xff);
-}
-
-static struct task_struct *getthread(struct pt_regs *regs, int tid)
-{
-	/*
-	 * Non-positive TIDs are remapped idle tasks:
-	 */
-	if (tid <= 0)
-		return idle_task(-tid);
-
-	/*
-	 * find_task_by_pid() does not take the tasklist lock anymore
-	 * but is nicely RCU locked - hence is a pretty resilient
-	 * thing to use:
-	 */
-	return find_task_by_pid(tid);
-}
-
-/*
- * CPU debug state control:
- */
-
-#ifdef CONFIG_SMP
-static void kgdb_wait(struct pt_regs *regs)
-{
-	unsigned long flags;
-	int cpu;
-
-	local_irq_save(flags);
-	cpu = raw_smp_processor_id();
-	kgdb_info[cpu].debuggerinfo = regs;
-	kgdb_info[cpu].task = current;
-	/*
-	 * Make sure the above info reaches the primary CPU before
-	 * our cpu_in_kgdb[] flag setting does:
-	 */
-	smp_wmb();
-	atomic_set(&cpu_in_kgdb[cpu], 1);
-
-	/*
-	 * The primary CPU must be active to enter here, but this is
-	 * guard in case the primary CPU had not been selected if
-	 * this was an entry via nmi.
-	 */
-	while (atomic_read(&kgdb_active) == -1)
-		cpu_relax();
-
-	/* Wait till primary CPU goes completely into the debugger. */
-	while (!atomic_read(&cpu_in_kgdb[atomic_read(&kgdb_active)]))
-		cpu_relax();
-
-	/* Wait till primary CPU is done with debugging */
-	while (atomic_read(&passive_cpu_wait[cpu]))
-		cpu_relax();
-
-	kgdb_info[cpu].debuggerinfo = NULL;
-	kgdb_info[cpu].task = NULL;
-
-	/* fix up hardware debug registers on local cpu */
-	if (arch_kgdb_ops.correct_hw_break)
-		arch_kgdb_ops.correct_hw_break();
-
-	/* Signal the primary CPU that we are done: */
-	atomic_set(&cpu_in_kgdb[cpu], 0);
-	clocksource_touch_watchdog();
-	local_irq_restore(flags);
-}
-#endif
-
-/*
- * Some architectures need cache flushes when we set/clear a
- * breakpoint:
- */
-static void kgdb_flush_swbreak_addr(unsigned long addr)
-{
-	if (!CACHE_FLUSH_IS_SAFE)
-		return;
-
-	if (current->mm) {
-		flush_cache_range(current->mm->mmap_cache,
-				  addr, addr + BREAK_INSTR_SIZE);
-	} else {
-		flush_icache_range(addr, addr + BREAK_INSTR_SIZE);
-	}
-}
-
-/*
- * SW breakpoint management:
- */
-static int kgdb_activate_sw_breakpoints(void)
-{
-	unsigned long addr;
-	int error = 0;
-	int i;
-
-	for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
-		if (kgdb_break[i].state != BP_SET)
-			continue;
-
-		addr = kgdb_break[i].bpt_addr;
-		error = kgdb_arch_set_breakpoint(addr,
-				kgdb_break[i].saved_instr);
-		if (error)
-			return error;
-
-		kgdb_flush_swbreak_addr(addr);
-		kgdb_break[i].state = BP_ACTIVE;
-	}
-	return 0;
-}
-
-static int kgdb_set_sw_break(unsigned long addr)
-{
-	int err = kgdb_validate_break_address(addr);
-	int breakno = -1;
-	int i;
-
-	if (err)
-		return err;
-
-	for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
-		if ((kgdb_break[i].state == BP_SET) &&
-					(kgdb_break[i].bpt_addr == addr))
-			return -EEXIST;
-	}
-	for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
-		if (kgdb_break[i].state == BP_REMOVED &&
-					kgdb_break[i].bpt_addr == addr) {
-			breakno = i;
-			break;
-		}
-	}
-
-	if (breakno == -1) {
-		for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
-			if (kgdb_break[i].state == BP_UNDEFINED) {
-				breakno = i;
-				break;
-			}
-		}
-	}
-
-	if (breakno == -1)
-		return -E2BIG;
-
-	kgdb_break[breakno].state = BP_SET;
-	kgdb_break[breakno].type = BP_BREAKPOINT;
-	kgdb_break[breakno].bpt_addr = addr;
-
-	return 0;
-}
-
-static int kgdb_deactivate_sw_breakpoints(void)
-{
-	unsigned long addr;
-	int error = 0;
-	int i;
-
-	for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
-		if (kgdb_break[i].state != BP_ACTIVE)
-			continue;
-		addr = kgdb_break[i].bpt_addr;
-		error = kgdb_arch_remove_breakpoint(addr,
-					kgdb_break[i].saved_instr);
-		if (error)
-			return error;
-
-		kgdb_flush_swbreak_addr(addr);
-		kgdb_break[i].state = BP_SET;
-	}
-	return 0;
-}
-
-static int kgdb_remove_sw_break(unsigned long addr)
-{
-	int i;
-
-	for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
-		if ((kgdb_break[i].state == BP_SET) &&
-				(kgdb_break[i].bpt_addr == addr)) {
-			kgdb_break[i].state = BP_REMOVED;
-			return 0;
-		}
-	}
-	return -ENOENT;
-}
-
-int kgdb_isremovedbreak(unsigned long addr)
-{
-	int i;
-
-	for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
-		if ((kgdb_break[i].state == BP_REMOVED) &&
-					(kgdb_break[i].bpt_addr == addr))
-			return 1;
-	}
-	return 0;
-}
-
-int remove_all_break(void)
-{
-	unsigned long addr;
-	int error;
-	int i;
-
-	/* Clear memory breakpoints. */
-	for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
-		if (kgdb_break[i].state != BP_SET)
-			continue;
-		addr = kgdb_break[i].bpt_addr;
-		error = kgdb_arch_remove_breakpoint(addr,
-				kgdb_break[i].saved_instr);
-		if (error)
-			return error;
-		kgdb_break[i].state = BP_REMOVED;
-	}
-
-	/* Clear hardware breakpoints. */
-	if (arch_kgdb_ops.remove_all_hw_break)
-		arch_kgdb_ops.remove_all_hw_break();
-
-	return 0;
-}
-
-/*
- * Remap normal tasks to their real PID, idle tasks to -1 ... -NR_CPUs:
- */
-static inline int shadow_pid(int realpid)
-{
-	if (realpid)
-		return realpid;
-
-	return -1-raw_smp_processor_id();
-}
-
-static char gdbmsgbuf[BUFMAX + 1];
-
-static void kgdb_msg_write(const char *s, int len)
-{
-	char *bufptr;
-	int wcount;
-	int i;
-
-	/* 'O'utput */
-	gdbmsgbuf[0] = 'O';
-
-	/* Fill and send buffers... */
-	while (len > 0) {
-		bufptr = gdbmsgbuf + 1;
-
-		/* Calculate how many this time */
-		if ((len << 1) > (BUFMAX - 2))
-			wcount = (BUFMAX - 2) >> 1;
-		else
-			wcount = len;
-
-		/* Pack in hex chars */
-		for (i = 0; i < wcount; i++)
-			bufptr = pack_hex_byte(bufptr, s[i]);
-		*bufptr = '\0';
-
-		/* Move up */
-		s += wcount;
-		len -= wcount;
-
-		/* Write packet */
-		put_packet(gdbmsgbuf);
-	}
-}
-
-/*
- * Return true if there is a valid kgdb I/O module.  Also if no
- * debugger is attached a message can be printed to the console about
- * waiting for the debugger to attach.
- *
- * The print_wait argument is only to be true when called from inside
- * the core kgdb_handle_exception, because it will wait for the
- * debugger to attach.
- */
-static int kgdb_io_ready(int print_wait)
-{
-	if (!kgdb_io_ops)
-		return 0;
-	if (kgdb_connected)
-		return 1;
-	if (atomic_read(&kgdb_setting_breakpoint))
-		return 1;
-	if (print_wait)
-		printk(KERN_CRIT "KGDB: Waiting for remote debugger\n");
-	return 1;
-}
-
-/*
- * All the functions that start with gdb_cmd are the various
- * operations to implement the handlers for the gdbserial protocol
- * where KGDB is communicating with an external debugger
- */
-
-/* Handle the '?' status packets */
-static void gdb_cmd_status(struct kgdb_state *ks)
-{
-	/*
-	 * We know that this packet is only sent
-	 * during initial connect.  So to be safe,
-	 * we clear out our breakpoints now in case
-	 * GDB is reconnecting.
-	 */
-	remove_all_break();
-
-	remcom_out_buffer[0] = 'S';
-	pack_hex_byte(&remcom_out_buffer[1], ks->signo);
-}
-
-/* Handle the 'g' get registers request */
-static void gdb_cmd_getregs(struct kgdb_state *ks)
-{
-	struct task_struct *thread;
-	void *local_debuggerinfo;
-	int i;
-
-	thread = kgdb_usethread;
-	if (!thread) {
-		thread = kgdb_info[ks->cpu].task;
-		local_debuggerinfo = kgdb_info[ks->cpu].debuggerinfo;
-	} else {
-		local_debuggerinfo = NULL;
-		for (i = 0; i < NR_CPUS; i++) {
-			/*
-			 * Try to find the task on some other
-			 * or possibly this node if we do not
-			 * find the matching task then we try
-			 * to approximate the results.
-			 */
-			if (thread == kgdb_info[i].task)
-				local_debuggerinfo = kgdb_info[i].debuggerinfo;
-		}
-	}
-
-	/*
-	 * All threads that don't have debuggerinfo should be
-	 * in __schedule() sleeping, since all other CPUs
-	 * are in kgdb_wait, and thus have debuggerinfo.
-	 */
-	if (local_debuggerinfo) {
-		pt_regs_to_gdb_regs(gdb_regs, local_debuggerinfo);
-	} else {
-		/*
-		 * Pull stuff saved during switch_to; nothing
-		 * else is accessible (or even particularly
-		 * relevant).
-		 *
-		 * This should be enough for a stack trace.
-		 */
-		sleeping_thread_to_gdb_regs(gdb_regs, thread);
-	}
-	kgdb_mem2hex((char *)gdb_regs, remcom_out_buffer, NUMREGBYTES);
-}
-
-/* Handle the 'G' set registers request */
-static void gdb_cmd_setregs(struct kgdb_state *ks)
-{
-	kgdb_hex2mem(&remcom_in_buffer[1], (char *)gdb_regs, NUMREGBYTES);
-
-	if (kgdb_usethread && kgdb_usethread != current) {
-		error_packet(remcom_out_buffer, -EINVAL);
-	} else {
-		gdb_regs_to_pt_regs(gdb_regs, ks->linux_regs);
-		strcpy(remcom_out_buffer, "OK");
-	}
-}
-
-/* Handle the 'm' memory read bytes */
-static void gdb_cmd_memread(struct kgdb_state *ks)
-{
-	char *ptr = &remcom_in_buffer[1];
-	unsigned long length;
-	unsigned long addr;
-	int err;
-
-	if (kgdb_hex2long(&ptr, &addr) > 0 && *ptr++ == ',' &&
-					kgdb_hex2long(&ptr, &length) > 0) {
-		err = kgdb_mem2hex((char *)addr, remcom_out_buffer, length);
-		if (err)
-			error_packet(remcom_out_buffer, err);
-	} else {
-		error_packet(remcom_out_buffer, -EINVAL);
-	}
-}
-
-/* Handle the 'M' memory write bytes */
-static void gdb_cmd_memwrite(struct kgdb_state *ks)
-{
-	int err = write_mem_msg(0);
-
-	if (err)
-		error_packet(remcom_out_buffer, err);
-	else
-		strcpy(remcom_out_buffer, "OK");
-}
-
-/* Handle the 'X' memory binary write bytes */
-static void gdb_cmd_binwrite(struct kgdb_state *ks)
-{
-	int err = write_mem_msg(1);
-
-	if (err)
-		error_packet(remcom_out_buffer, err);
-	else
-		strcpy(remcom_out_buffer, "OK");
-}
-
-/* Handle the 'D' or 'k', detach or kill packets */
-static void gdb_cmd_detachkill(struct kgdb_state *ks)
-{
-	int error;
-
-	/* The detach case */
-	if (remcom_in_buffer[0] == 'D') {
-		error = remove_all_break();
-		if (error < 0) {
-			error_packet(remcom_out_buffer, error);
-		} else {
-			strcpy(remcom_out_buffer, "OK");
-			kgdb_connected = 0;
-		}
-		put_packet(remcom_out_buffer);
-	} else {
-		/*
-		 * Assume the kill case, with no exit code checking,
-		 * trying to force detach the debugger:
-		 */
-		remove_all_break();
-		kgdb_connected = 0;
-	}
-}
-
-/* Handle the 'R' reboot packets */
-static int gdb_cmd_reboot(struct kgdb_state *ks)
-{
-	/* For now, only honor R0 */
-	if (strcmp(remcom_in_buffer, "R0") == 0) {
-		printk(KERN_CRIT "Executing emergency reboot\n");
-		strcpy(remcom_out_buffer, "OK");
-		put_packet(remcom_out_buffer);
-
-		/*
-		 * Execution should not return from
-		 * machine_emergency_restart()
-		 */
-		machine_emergency_restart();
-		kgdb_connected = 0;
-
-		return 1;
-	}
-	return 0;
-}
-
-/* Handle the 'q' query packets */
-static void gdb_cmd_query(struct kgdb_state *ks)
-{
-	struct task_struct *thread;
-	unsigned char thref[8];
-	char *ptr;
-	int i;
-
-	switch (remcom_in_buffer[1]) {
-	case 's':
-	case 'f':
-		if (memcmp(remcom_in_buffer + 2, "ThreadInfo", 10)) {
-			error_packet(remcom_out_buffer, -EINVAL);
-			break;
-		}
-
-		if (remcom_in_buffer[1] == 'f')
-			ks->threadid = 1;
-
-		remcom_out_buffer[0] = 'm';
-		ptr = remcom_out_buffer + 1;
-
-		for (i = 0; i < 17; ks->threadid++) {
-			thread = getthread(ks->linux_regs, ks->threadid);
-			if (thread) {
-				int_to_threadref(thref, ks->threadid);
-				pack_threadid(ptr, thref);
-				ptr += BUF_THREAD_ID_SIZE;
-				*(ptr++) = ',';
-				i++;
-			}
-		}
-		*(--ptr) = '\0';
-		break;
-
-	case 'C':
-		/* Current thread id */
-		strcpy(remcom_out_buffer, "QC");
-		ks->threadid = shadow_pid(current->pid);
-		int_to_threadref(thref, ks->threadid);
-		pack_threadid(remcom_out_buffer + 2, thref);
-		break;
-	case 'T':
-		if (memcmp(remcom_in_buffer + 1, "ThreadExtraInfo,", 16)) {
-			error_packet(remcom_out_buffer, -EINVAL);
-			break;
-		}
-		ks->threadid = 0;
-		ptr = remcom_in_buffer + 17;
-		kgdb_hex2long(&ptr, &ks->threadid);
-		if (!getthread(ks->linux_regs, ks->threadid)) {
-			error_packet(remcom_out_buffer, -EINVAL);
-			break;
-		}
-		if (ks->threadid > 0) {
-			kgdb_mem2hex(getthread(ks->linux_regs,
-					ks->threadid)->comm,
-					remcom_out_buffer, 16);
-		} else {
-			static char tmpstr[23 + BUF_THREAD_ID_SIZE];
-
-			sprintf(tmpstr, "Shadow task %d for pid 0",
-					(int)(-ks->threadid-1));
-			kgdb_mem2hex(tmpstr, remcom_out_buffer, strlen(tmpstr));
-		}
-		break;
-	}
-}
-
-/* Handle the 'H' task query packets */
-static void gdb_cmd_task(struct kgdb_state *ks)
-{
-	struct task_struct *thread;
-	char *ptr;
-
-	switch (remcom_in_buffer[1]) {
-	case 'g':
-		ptr = &remcom_in_buffer[2];
-		kgdb_hex2long(&ptr, &ks->threadid);
-		thread = getthread(ks->linux_regs, ks->threadid);
-		if (!thread && ks->threadid > 0) {
-			error_packet(remcom_out_buffer, -EINVAL);
-			break;
-		}
-		kgdb_usethread = thread;
-		ks->kgdb_usethreadid = ks->threadid;
-		strcpy(remcom_out_buffer, "OK");
-		break;
-	case 'c':
-		ptr = &remcom_in_buffer[2];
-		kgdb_hex2long(&ptr, &ks->threadid);
-		if (!ks->threadid) {
-			kgdb_contthread = NULL;
-		} else {
-			thread = getthread(ks->linux_regs, ks->threadid);
-			if (!thread && ks->threadid > 0) {
-				error_packet(remcom_out_buffer, -EINVAL);
-				break;
-			}
-			kgdb_contthread = thread;
-		}
-		strcpy(remcom_out_buffer, "OK");
-		break;
-	}
-}
-
-/* Handle the 'T' thread query packets */
-static void gdb_cmd_thread(struct kgdb_state *ks)
-{
-	char *ptr = &remcom_in_buffer[1];
-	struct task_struct *thread;
-
-	kgdb_hex2long(&ptr, &ks->threadid);
-	thread = getthread(ks->linux_regs, ks->threadid);
-	if (thread)
-		strcpy(remcom_out_buffer, "OK");
-	else
-		error_packet(remcom_out_buffer, -EINVAL);
-}
-
-/* Handle the 'z' or 'Z' breakpoint remove or set packets */
-static void gdb_cmd_break(struct kgdb_state *ks)
-{
-	/*
-	 * Since GDB-5.3, it's been drafted that '0' is a software
-	 * breakpoint, '1' is a hardware breakpoint, so let's do that.
-	 */
-	char *bpt_type = &remcom_in_buffer[1];
-	char *ptr = &remcom_in_buffer[2];
-	unsigned long addr;
-	unsigned long length;
-	int error = 0;
-
-	if (arch_kgdb_ops.set_hw_breakpoint && *bpt_type >= '1') {
-		/* Unsupported */
-		if (*bpt_type > '4')
-			return;
-	} else {
-		if (*bpt_type != '0' && *bpt_type != '1')
-			/* Unsupported. */
-			return;
-	}
-
-	/*
-	 * Test if this is a hardware breakpoint, and
-	 * if we support it:
-	 */
-	if (*bpt_type == '1' && !(arch_kgdb_ops.flags & KGDB_HW_BREAKPOINT))
-		/* Unsupported. */
-		return;
-
-	if (*(ptr++) != ',') {
-		error_packet(remcom_out_buffer, -EINVAL);
-		return;
-	}
-	if (!kgdb_hex2long(&ptr, &addr)) {
-		error_packet(remcom_out_buffer, -EINVAL);
-		return;
-	}
-	if (*(ptr++) != ',' ||
-		!kgdb_hex2long(&ptr, &length)) {
-		error_packet(remcom_out_buffer, -EINVAL);
-		return;
-	}
-
-	if (remcom_in_buffer[0] == 'Z' && *bpt_type == '0')
-		error = kgdb_set_sw_break(addr);
-	else if (remcom_in_buffer[0] == 'z' && *bpt_type == '0')
-		error = kgdb_remove_sw_break(addr);
-	else if (remcom_in_buffer[0] == 'Z')
-		error = arch_kgdb_ops.set_hw_breakpoint(addr,
-			(int)length, *bpt_type - '0');
-	else if (remcom_in_buffer[0] == 'z')
-		error = arch_kgdb_ops.remove_hw_breakpoint(addr,
-			(int) length, *bpt_type - '0');
-
-	if (error == 0)
-		strcpy(remcom_out_buffer, "OK");
-	else
-		error_packet(remcom_out_buffer, error);
-}
-
-/* Handle the 'C' signal / exception passing packets */
-static int gdb_cmd_exception_pass(struct kgdb_state *ks)
-{
-	/* C09 == pass exception
-	 * C15 == detach kgdb, pass exception
-	 */
-	if (remcom_in_buffer[1] == '0' && remcom_in_buffer[2] == '9') {
-
-		ks->pass_exception = 1;
-		remcom_in_buffer[0] = 'c';
-
-	} else if (remcom_in_buffer[1] == '1' && remcom_in_buffer[2] == '5') {
-
-		ks->pass_exception = 1;
-		remcom_in_buffer[0] = 'D';
-		remove_all_break();
-		kgdb_connected = 0;
-		return 1;
-
-	} else {
-		error_packet(remcom_out_buffer, -EINVAL);
-		return 0;
-	}
-
-	/* Indicate fall through */
-	return -1;
-}
-
-/*
- * This function performs all gdbserial command procesing
- */
-static int gdb_serial_stub(struct kgdb_state *ks)
-{
-	int error = 0;
-	int tmp;
-
-	/* Clear the out buffer. */
-	memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer));
-
-	if (kgdb_connected) {
-		unsigned char thref[8];
-		char *ptr;
-
-		/* Reply to host that an exception has occurred */
-		ptr = remcom_out_buffer;
-		*ptr++ = 'T';
-		ptr = pack_hex_byte(ptr, ks->signo);
-		ptr += strlen(strcpy(ptr, "thread:"));
-		int_to_threadref(thref, shadow_pid(current->pid));
-		ptr = pack_threadid(ptr, thref);
-		*ptr++ = ';';
-		put_packet(remcom_out_buffer);
-	}
-
-	kgdb_usethread = kgdb_info[ks->cpu].task;
-	ks->kgdb_usethreadid = shadow_pid(kgdb_info[ks->cpu].task->pid);
-	ks->pass_exception = 0;
-
-	while (1) {
-		error = 0;
-
-		/* Clear the out buffer. */
-		memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer));
-
-		get_packet(remcom_in_buffer);
-
-		switch (remcom_in_buffer[0]) {
-		case '?': /* gdbserial status */
-			gdb_cmd_status(ks);
-			break;
-		case 'g': /* return the value of the CPU registers */
-			gdb_cmd_getregs(ks);
-			break;
-		case 'G': /* set the value of the CPU registers - return OK */
-			gdb_cmd_setregs(ks);
-			break;
-		case 'm': /* mAA..AA,LLLL  Read LLLL bytes at address AA..AA */
-			gdb_cmd_memread(ks);
-			break;
-		case 'M': /* MAA..AA,LLLL: Write LLLL bytes at address AA..AA */
-			gdb_cmd_memwrite(ks);
-			break;
-		case 'X': /* XAA..AA,LLLL: Write LLLL bytes at address AA..AA */
-			gdb_cmd_binwrite(ks);
-			break;
-			/* kill or detach. KGDB should treat this like a
-			 * continue.
-			 */
-		case 'D': /* Debugger detach */
-		case 'k': /* Debugger detach via kill */
-			gdb_cmd_detachkill(ks);
-			goto default_handle;
-		case 'R': /* Reboot */
-			if (gdb_cmd_reboot(ks))
-				goto default_handle;
-			break;
-		case 'q': /* query command */
-			gdb_cmd_query(ks);
-			break;
-		case 'H': /* task related */
-			gdb_cmd_task(ks);
-			break;
-		case 'T': /* Query thread status */
-			gdb_cmd_thread(ks);
-			break;
-		case 'z': /* Break point remove */
-		case 'Z': /* Break point set */
-			gdb_cmd_break(ks);
-			break;
-		case 'C': /* Exception passing */
-			tmp = gdb_cmd_exception_pass(ks);
-			if (tmp > 0)
-				goto default_handle;
-			if (tmp == 0)
-				break;
-			/* Fall through on tmp < 0 */
-		case 'c': /* Continue packet */
-		case 's': /* Single step packet */
-			if (kgdb_contthread && kgdb_contthread != current) {
-				/* Can't switch threads in kgdb */
-				error_packet(remcom_out_buffer, -EINVAL);
-				break;
-			}
-			kgdb_activate_sw_breakpoints();
-			/* Fall through to default processing */
-		default:
-default_handle:
-			error = kgdb_arch_handle_exception(ks->ex_vector,
-						ks->signo,
-						ks->err_code,
-						remcom_in_buffer,
-						remcom_out_buffer,
-						ks->linux_regs);
-			/*
-			 * Leave cmd processing on error, detach,
-			 * kill, continue, or single step.
-			 */
-			if (error >= 0 || remcom_in_buffer[0] == 'D' ||
-			    remcom_in_buffer[0] == 'k') {
-				error = 0;
-				goto kgdb_exit;
-			}
-
-		}
-
-		/* reply to the request */
-		put_packet(remcom_out_buffer);
-	}
-
-kgdb_exit:
-	if (ks->pass_exception)
-		error = 1;
-	return error;
-}
-
-static int kgdb_reenter_check(struct kgdb_state *ks)
-{
-	unsigned long addr;
-
-	if (atomic_read(&kgdb_active) != raw_smp_processor_id())
-		return 0;
-
-	/* Panic on recursive debugger calls: */
-	exception_level++;
-	addr = kgdb_arch_pc(ks->ex_vector, ks->linux_regs);
-	kgdb_deactivate_sw_breakpoints();
-
-	/*
-	 * If the break point removed ok at the place exception
-	 * occurred, try to recover and print a warning to the end
-	 * user because the user planted a breakpoint in a place that
-	 * KGDB needs in order to function.
-	 */
-	if (kgdb_remove_sw_break(addr) == 0) {
-		exception_level = 0;
-		kgdb_skipexception(ks->ex_vector, ks->linux_regs);
-		kgdb_activate_sw_breakpoints();
-		printk(KERN_CRIT "KGDB: re-enter error: breakpoint removed %lx\n",
-			addr);
-		WARN_ON_ONCE(1);
-
-		return 1;
-	}
-	remove_all_break();
-	kgdb_skipexception(ks->ex_vector, ks->linux_regs);
-
-	if (exception_level > 1) {
-		dump_stack();
-		panic("Recursive entry to debugger");
-	}
-
-	printk(KERN_CRIT "KGDB: re-enter exception: ALL breakpoints killed\n");
-	dump_stack();
-	panic("Recursive entry to debugger");
-
-	return 1;
-}
-
-/*
- * kgdb_handle_exception() - main entry point from a kernel exception
- *
- * Locking hierarchy:
- *	interface locks, if any (begin_session)
- *	kgdb lock (kgdb_active)
- */
-int
-kgdb_handle_exception(int evector, int signo, int ecode, struct pt_regs *regs)
-{
-	struct kgdb_state kgdb_var;
-	struct kgdb_state *ks = &kgdb_var;
-	unsigned long flags;
-	int error = 0;
-	int i, cpu;
-
-	ks->cpu			= raw_smp_processor_id();
-	ks->ex_vector		= evector;
-	ks->signo		= signo;
-	ks->ex_vector		= evector;
-	ks->err_code		= ecode;
-	ks->kgdb_usethreadid	= 0;
-	ks->linux_regs		= regs;
-
-	if (kgdb_reenter_check(ks))
-		return 0; /* Ouch, double exception ! */
-
-acquirelock:
-	/*
-	 * Interrupts will be restored by the 'trap return' code, except when
-	 * single stepping.
-	 */
-	local_irq_save(flags);
-
-	cpu = raw_smp_processor_id();
-
-	/*
-	 * Acquire the kgdb_active lock:
-	 */
-	while (atomic_cmpxchg(&kgdb_active, -1, cpu) != -1)
-		cpu_relax();
-
-	/*
-	 * Do not start the debugger connection on this CPU if the last
-	 * instance of the exception handler wanted to come into the
-	 * debugger on a different CPU via a single step
-	 */
-	if (atomic_read(&kgdb_cpu_doing_single_step) != -1 &&
-	    atomic_read(&kgdb_cpu_doing_single_step) != cpu) {
-
-		atomic_set(&kgdb_active, -1);
-		clocksource_touch_watchdog();
-		local_irq_restore(flags);
-
-		goto acquirelock;
-	}
-
-	if (!kgdb_io_ready(1)) {
-		error = 1;
-		goto kgdb_restore; /* No I/O connection, so resume the system */
-	}
-
-	/*
-	 * Don't enter if we have hit a removed breakpoint.
-	 */
-	if (kgdb_skipexception(ks->ex_vector, ks->linux_regs))
-		goto kgdb_restore;
-
-	/* Call the I/O driver's pre_exception routine */
-	if (kgdb_io_ops->pre_exception)
-		kgdb_io_ops->pre_exception();
-
-	kgdb_info[ks->cpu].debuggerinfo = ks->linux_regs;
-	kgdb_info[ks->cpu].task = current;
-
-	kgdb_disable_hw_debug(ks->linux_regs);
-
-	/*
-	 * Get the passive CPU lock which will hold all the non-primary
-	 * CPU in a spin state while the debugger is active
-	 */
-	if (!kgdb_single_step || !kgdb_contthread) {
-		for (i = 0; i < NR_CPUS; i++)
-			atomic_set(&passive_cpu_wait[i], 1);
-	}
-
-#ifdef CONFIG_SMP
-	/* Signal the other CPUs to enter kgdb_wait() */
-	if (!kgdb_single_step || !kgdb_contthread)
-		kgdb_roundup_cpus(flags);
-#endif
-
-	/*
-	 * spin_lock code is good enough as a barrier so we don't
-	 * need one here:
-	 */
-	atomic_set(&cpu_in_kgdb[ks->cpu], 1);
-
-	/*
-	 * Wait for the other CPUs to be notified and be waiting for us:
-	 */
-	for_each_online_cpu(i) {
-		while (!atomic_read(&cpu_in_kgdb[i]))
-			cpu_relax();
-	}
-
-	/*
-	 * At this point the primary processor is completely
-	 * in the debugger and all secondary CPUs are quiescent
-	 */
-	kgdb_post_primary_code(ks->linux_regs, ks->ex_vector, ks->err_code);
-	kgdb_deactivate_sw_breakpoints();
-	kgdb_single_step = 0;
-	kgdb_contthread = NULL;
-	exception_level = 0;
-
-	/* Talk to debugger with gdbserial protocol */
-	error = gdb_serial_stub(ks);
-
-	/* Call the I/O driver's post_exception routine */
-	if (kgdb_io_ops->post_exception)
-		kgdb_io_ops->post_exception();
-
-	kgdb_info[ks->cpu].debuggerinfo = NULL;
-	kgdb_info[ks->cpu].task = NULL;
-	atomic_set(&cpu_in_kgdb[ks->cpu], 0);
-
-	if (!kgdb_single_step || !kgdb_contthread) {
-		for (i = NR_CPUS-1; i >= 0; i--)
-			atomic_set(&passive_cpu_wait[i], 0);
-		/*
-		 * Wait till all the CPUs have quit
-		 * from the debugger.
-		 */
-		for_each_online_cpu(i) {
-			while (atomic_read(&cpu_in_kgdb[i]))
-				cpu_relax();
-		}
-	}
-
-kgdb_restore:
-	/* Free kgdb_active */
-	atomic_set(&kgdb_active, -1);
-	clocksource_touch_watchdog();
-	local_irq_restore(flags);
-
-	return error;
-}
-
-int kgdb_nmicallback(int cpu, void *regs)
-{
-#ifdef CONFIG_SMP
-	if (!atomic_read(&cpu_in_kgdb[cpu]) &&
-			atomic_read(&kgdb_active) != cpu) {
-		kgdb_wait((struct pt_regs *)regs);
-		return 0;
-	}
-#endif
-	return 1;
-}
-
-void kgdb_console_write(struct console *co, const char *s, unsigned count)
-{
-	unsigned long flags;
-
-	/* If we're debugging, or KGDB has not connected, don't try
-	 * and print. */
-	if (!kgdb_connected || atomic_read(&kgdb_active) != -1)
-		return;
-
-	local_irq_save(flags);
-	kgdb_msg_write(s, count);
-	local_irq_restore(flags);
-}
-
-static struct console kgdbcons = {
-	.name		= "kgdb",
-	.write		= kgdb_console_write,
-	.flags		= CON_PRINTBUFFER | CON_ENABLED,
-	.index		= -1,
-};
-
-#ifdef CONFIG_MAGIC_SYSRQ
-static void sysrq_handle_gdb(int key, struct tty_struct *tty)
-{
-	if (!kgdb_io_ops) {
-		printk(KERN_CRIT "ERROR: No KGDB I/O module available\n");
-		return;
-	}
-	if (!kgdb_connected)
-		printk(KERN_CRIT "Entering KGDB\n");
-
-	kgdb_breakpoint();
-}
-
-static struct sysrq_key_op sysrq_gdb_op = {
-	.handler	= sysrq_handle_gdb,
-	.help_msg	= "Gdb",
-	.action_msg	= "GDB",
-};
-#endif
-
-static void kgdb_register_callbacks(void)
-{
-	if (!kgdb_io_module_registered) {
-		kgdb_io_module_registered = 1;
-		kgdb_arch_init();
-#ifdef CONFIG_MAGIC_SYSRQ
-		register_sysrq_key('g', &sysrq_gdb_op);
-#endif
-		if (kgdb_use_con && !kgdb_con_registered) {
-			register_console(&kgdbcons);
-			kgdb_con_registered = 1;
-		}
-	}
-}
-
-static void kgdb_unregister_callbacks(void)
-{
-	/*
-	 * When this routine is called KGDB should unregister from the
-	 * panic handler and clean up, making sure it is not handling any
-	 * break exceptions at the time.
-	 */
-	if (kgdb_io_module_registered) {
-		kgdb_io_module_registered = 0;
-		kgdb_arch_exit();
-#ifdef CONFIG_MAGIC_SYSRQ
-		unregister_sysrq_key('g', &sysrq_gdb_op);
-#endif
-		if (kgdb_con_registered) {
-			unregister_console(&kgdbcons);
-			kgdb_con_registered = 0;
-		}
-	}
-}
-
-static void kgdb_initial_breakpoint(void)
-{
-	kgdb_break_asap = 0;
-
-	printk(KERN_CRIT "kgdb: Waiting for connection from remote gdb...\n");
-	kgdb_breakpoint();
-}
-
-/**
- *	kkgdb_register_io_module - register KGDB IO module
- *	@new_kgdb_io_ops: the io ops vector
- *
- *	Register it with the KGDB core.
- */
-int kgdb_register_io_module(struct kgdb_io *new_kgdb_io_ops)
-{
-	int err;
-
-	spin_lock(&kgdb_registration_lock);
-
-	if (kgdb_io_ops) {
-		spin_unlock(&kgdb_registration_lock);
-
-		printk(KERN_ERR "kgdb: Another I/O driver is already "
-				"registered with KGDB.\n");
-		return -EBUSY;
-	}
-
-	if (new_kgdb_io_ops->init) {
-		err = new_kgdb_io_ops->init();
-		if (err) {
-			spin_unlock(&kgdb_registration_lock);
-			return err;
-		}
-	}
-
-	kgdb_io_ops = new_kgdb_io_ops;
-
-	spin_unlock(&kgdb_registration_lock);
-
-	printk(KERN_INFO "kgdb: Registered I/O driver %s.\n",
-	       new_kgdb_io_ops->name);
-
-	/* Arm KGDB now. */
-	kgdb_register_callbacks();
-
-	if (kgdb_break_asap)
-		kgdb_initial_breakpoint();
-
-	return 0;
-}
-EXPORT_SYMBOL_GPL(kgdb_register_io_module);
-
-/**
- *	kkgdb_unregister_io_module - unregister KGDB IO module
- *	@old_kgdb_io_ops: the io ops vector
- *
- *	Unregister it with the KGDB core.
- */
-void kgdb_unregister_io_module(struct kgdb_io *old_kgdb_io_ops)
-{
-	BUG_ON(kgdb_connected);
-
-	/*
-	 * KGDB is no longer able to communicate out, so
-	 * unregister our callbacks and reset state.
-	 */
-	kgdb_unregister_callbacks();
-
-	spin_lock(&kgdb_registration_lock);
-
-	WARN_ON_ONCE(kgdb_io_ops != old_kgdb_io_ops);
-	kgdb_io_ops = NULL;
-
-	spin_unlock(&kgdb_registration_lock);
-
-	printk(KERN_INFO
-		"kgdb: Unregistered I/O driver %s, debugger disabled.\n",
-		old_kgdb_io_ops->name);
-}
-EXPORT_SYMBOL_GPL(kgdb_unregister_io_module);
-
-/**
- * kgdb_breakpoint - generate breakpoint exception
- *
- * This function will generate a breakpoint exception.  It is used at the
- * beginning of a program to sync up with a debugger and can be used
- * otherwise as a quick means to stop program execution and "break" into
- * the debugger.
- */
-void kgdb_breakpoint(void)
-{
-	atomic_set(&kgdb_setting_breakpoint, 1);
-	wmb(); /* Sync point before breakpoint */
-	arch_kgdb_breakpoint();
-	wmb(); /* Sync point after breakpoint */
-	atomic_set(&kgdb_setting_breakpoint, 0);
-}
-EXPORT_SYMBOL_GPL(kgdb_breakpoint);
-
-static int __init opt_kgdb_wait(char *str)
-{
-	kgdb_break_asap = 1;
-
-	if (kgdb_io_module_registered)
-		kgdb_initial_breakpoint();
-
-	return 0;
-}
-
-early_param("kgdbwait", opt_kgdb_wait);
diff --git a/lib/kgdb.c b/lib/kgdb.c
new file mode 100644
index 0000000..a453764
--- /dev/null
+++ b/lib/kgdb.c
@@ -0,0 +1,1680 @@
+/*
+ * KGDB stub.
+ *
+ * Maintainer: Jason Wessel <jason.wessel@...driver.com>
+ *
+ * Copyright (C) 2000-2001 VERITAS Software Corporation.
+ * Copyright (C) 2002-2004 Timesys Corporation
+ * Copyright (C) 2003-2004 Amit S. Kale <amitkale@...syssoft.com>
+ * Copyright (C) 2004 Pavel Machek <pavel@...e.cz>
+ * Copyright (C) 2004-2006 Tom Rini <trini@...nel.crashing.org>
+ * Copyright (C) 2004-2006 LinSysSoft Technologies Pvt. Ltd.
+ * Copyright (C) 2005-2008 Wind River Systems, Inc.
+ * Copyright (C) 2007 MontaVista Software, Inc.
+ * Copyright (C) 2008 Red Hat, Inc., Ingo Molnar <mingo@...hat.com>
+ *
+ * Contributors at various stages not listed above:
+ *  Jason Wessel ( jason.wessel@...driver.com )
+ *  George Anzinger <george@...sta.com>
+ *  Anurekh Saxena (anurekh.saxena@...esys.com)
+ *  Lake Stevens Instrument Division (Glenn Engel)
+ *  Jim Kingdon, Cygnus Support.
+ *
+ * Original KGDB stub: David Grothe <dave@...m.com>,
+ * Tigran Aivazian <tigran@....com>
+ *
+ * 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/pid_namespace.h>
+#include <linux/clocksource.h>
+#include <linux/interrupt.h>
+#include <linux/spinlock.h>
+#include <linux/console.h>
+#include <linux/threads.h>
+#include <linux/uaccess.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/ptrace.h>
+#include <linux/reboot.h>
+#include <linux/string.h>
+#include <linux/delay.h>
+#include <linux/sched.h>
+#include <linux/sysrq.h>
+#include <linux/init.h>
+#include <linux/kgdb.h>
+#include <linux/pid.h>
+#include <linux/smp.h>
+#include <linux/mm.h>
+
+#include <asm/cacheflush.h>
+#include <asm/byteorder.h>
+#include <asm/atomic.h>
+#include <asm/system.h>
+
+static int kgdb_break_asap;
+
+struct kgdb_state {
+	int			ex_vector;
+	int			signo;
+	int			err_code;
+	int			cpu;
+	int			pass_exception;
+	long			threadid;
+	long			kgdb_usethreadid;
+	struct pt_regs		*linux_regs;
+};
+
+static struct debuggerinfo_struct {
+	void			*debuggerinfo;
+	struct task_struct	*task;
+} kgdb_info[NR_CPUS];
+
+/**
+ * kgdb_connected - Is a host GDB connected to us?
+ */
+int				kgdb_connected;
+EXPORT_SYMBOL_GPL(kgdb_connected);
+
+/* All the KGDB handlers are installed */
+static int			kgdb_io_module_registered;
+
+/* Guard for recursive entry */
+static int			exception_level;
+
+static struct kgdb_io		*kgdb_io_ops;
+static DEFINE_SPINLOCK(kgdb_registration_lock);
+
+/* kgdb console driver is loaded */
+static int kgdb_con_registered;
+/* determine if kgdb console output should be used */
+static int kgdb_use_con;
+
+static int __init opt_kgdb_con(char *str)
+{
+	kgdb_use_con = 1;
+	return 0;
+}
+
+early_param("kgdbcon", opt_kgdb_con);
+
+module_param(kgdb_use_con, int, 0644);
+
+/*
+ * Holds information about breakpoints in a kernel. These breakpoints are
+ * added and removed by gdb.
+ */
+static struct kgdb_bkpt		kgdb_break[KGDB_MAX_BREAKPOINTS] = {
+	[0 ... KGDB_MAX_BREAKPOINTS-1] = { .state = BP_UNDEFINED }
+};
+
+/*
+ * The CPU# of the active CPU, or -1 if none:
+ */
+atomic_t			kgdb_active = ATOMIC_INIT(-1);
+
+/*
+ * We use NR_CPUs not PERCPU, in case kgdb is used to debug early
+ * bootup code (which might not have percpu set up yet):
+ */
+static atomic_t			passive_cpu_wait[NR_CPUS];
+static atomic_t			cpu_in_kgdb[NR_CPUS];
+atomic_t			kgdb_setting_breakpoint;
+
+struct task_struct		*kgdb_usethread;
+struct task_struct		*kgdb_contthread;
+
+int				kgdb_single_step;
+
+/* Our I/O buffers. */
+static char			remcom_in_buffer[BUFMAX];
+static char			remcom_out_buffer[BUFMAX];
+
+/* Storage for the registers, in GDB format. */
+static unsigned long		gdb_regs[(NUMREGBYTES +
+					sizeof(unsigned long) - 1) /
+					sizeof(unsigned long)];
+
+/* to keep track of the CPU which is doing the single stepping*/
+atomic_t			kgdb_cpu_doing_single_step = ATOMIC_INIT(-1);
+
+/*
+ * Finally, some KGDB code :-)
+ */
+
+/*
+ * Weak aliases for breakpoint management,
+ * can be overriden by architectures when needed:
+ */
+int __weak kgdb_validate_break_address(unsigned long addr)
+{
+	char tmp_variable[BREAK_INSTR_SIZE];
+
+	return probe_kernel_read(tmp_variable, (char *)addr, BREAK_INSTR_SIZE);
+}
+
+int __weak kgdb_arch_set_breakpoint(unsigned long addr, char *saved_instr)
+{
+	int err;
+
+	err = probe_kernel_read(saved_instr, (char *)addr, BREAK_INSTR_SIZE);
+	if (err)
+		return err;
+
+	return probe_kernel_write((char *)addr, arch_kgdb_ops.gdb_bpt_instr,
+				  BREAK_INSTR_SIZE);
+}
+
+int __weak kgdb_arch_remove_breakpoint(unsigned long addr, char *bundle)
+{
+	return probe_kernel_write((char *)addr,
+				  (char *)bundle, BREAK_INSTR_SIZE);
+}
+
+unsigned long __weak kgdb_arch_pc(int exception, struct pt_regs *regs)
+{
+	return instruction_pointer(regs);
+}
+
+int __weak kgdb_arch_init(void)
+{
+	return 0;
+}
+
+/**
+ *	kgdb_disable_hw_debug - Disable hardware debugging while we in kgdb.
+ *	@regs: Current &struct pt_regs.
+ *
+ *	This function will be called if the particular architecture must
+ *	disable hardware debugging while it is processing gdb packets or
+ *	handling exception.
+ */
+void __weak kgdb_disable_hw_debug(struct pt_regs *regs)
+{
+}
+
+/*
+ * GDB remote protocol parser:
+ */
+
+static const char	hexchars[] = "0123456789abcdef";
+
+static int hex(char ch)
+{
+	if ((ch >= 'a') && (ch <= 'f'))
+		return ch - 'a' + 10;
+	if ((ch >= '0') && (ch <= '9'))
+		return ch - '0';
+	if ((ch >= 'A') && (ch <= 'F'))
+		return ch - 'A' + 10;
+	return -1;
+}
+
+/* scan for the sequence $<data>#<checksum> */
+static void get_packet(char *buffer)
+{
+	unsigned char checksum;
+	unsigned char xmitcsum;
+	int count;
+	char ch;
+
+	do {
+		/*
+		 * Spin and wait around for the start character, ignore all
+		 * other characters:
+		 */
+		while ((ch = (kgdb_io_ops->read_char())) != '$')
+			/* nothing */;
+
+		kgdb_connected = 1;
+		checksum = 0;
+		xmitcsum = -1;
+
+		count = 0;
+
+		/*
+		 * now, read until a # or end of buffer is found:
+		 */
+		while (count < (BUFMAX - 1)) {
+			ch = kgdb_io_ops->read_char();
+			if (ch == '#')
+				break;
+			checksum = checksum + ch;
+			buffer[count] = ch;
+			count = count + 1;
+		}
+		buffer[count] = 0;
+
+		if (ch == '#') {
+			xmitcsum = hex(kgdb_io_ops->read_char()) << 4;
+			xmitcsum += hex(kgdb_io_ops->read_char());
+
+			if (checksum != xmitcsum)
+				/* failed checksum */
+				kgdb_io_ops->write_char('-');
+			else
+				/* successful transfer */
+				kgdb_io_ops->write_char('+');
+			if (kgdb_io_ops->flush)
+				kgdb_io_ops->flush();
+		}
+	} while (checksum != xmitcsum);
+}
+
+/*
+ * Send the packet in buffer.
+ * Check for gdb connection if asked for.
+ */
+static void put_packet(char *buffer)
+{
+	unsigned char checksum;
+	int count;
+	char ch;
+
+	/*
+	 * $<packet info>#<checksum>.
+	 */
+	while (1) {
+		kgdb_io_ops->write_char('$');
+		checksum = 0;
+		count = 0;
+
+		while ((ch = buffer[count])) {
+			kgdb_io_ops->write_char(ch);
+			checksum += ch;
+			count++;
+		}
+
+		kgdb_io_ops->write_char('#');
+		kgdb_io_ops->write_char(hexchars[checksum >> 4]);
+		kgdb_io_ops->write_char(hexchars[checksum & 0xf]);
+		if (kgdb_io_ops->flush)
+			kgdb_io_ops->flush();
+
+		/* Now see what we get in reply. */
+		ch = kgdb_io_ops->read_char();
+
+		if (ch == 3)
+			ch = kgdb_io_ops->read_char();
+
+		/* If we get an ACK, we are done. */
+		if (ch == '+')
+			return;
+
+		/*
+		 * If we get the start of another packet, this means
+		 * that GDB is attempting to reconnect.  We will NAK
+		 * the packet being sent, and stop trying to send this
+		 * packet.
+		 */
+		if (ch == '$') {
+			kgdb_io_ops->write_char('-');
+			if (kgdb_io_ops->flush)
+				kgdb_io_ops->flush();
+			return;
+		}
+	}
+}
+
+static char *pack_hex_byte(char *pkt, u8 byte)
+{
+	*pkt++ = hexchars[byte >> 4];
+	*pkt++ = hexchars[byte & 0xf];
+
+	return pkt;
+}
+
+/*
+ * Convert the memory pointed to by mem into hex, placing result in buf.
+ * Return a pointer to the last char put in buf (null). May return an error.
+ */
+int kgdb_mem2hex(char *mem, char *buf, int count)
+{
+	char *tmp;
+	int err;
+
+	/*
+	 * We use the upper half of buf as an intermediate buffer for the
+	 * raw memory copy.  Hex conversion will work against this one.
+	 */
+	tmp = buf + count;
+
+	err = probe_kernel_read(tmp, mem, count);
+	if (!err) {
+		while (count > 0) {
+			buf = pack_hex_byte(buf, *tmp);
+			tmp++;
+			count--;
+		}
+
+		*buf = 0;
+	}
+
+	return err;
+}
+
+/*
+ * Copy the binary array pointed to by buf into mem.  Fix $, #, and
+ * 0x7d escaped with 0x7d.  Return a pointer to the character after
+ * the last byte written.
+ */
+static int kgdb_ebin2mem(char *buf, char *mem, int count)
+{
+	int err = 0;
+	char c;
+
+	while (count-- > 0) {
+		c = *buf++;
+		if (c == 0x7d)
+			c = *buf++ ^ 0x20;
+
+		err = probe_kernel_write(mem, &c, 1);
+		if (err)
+			break;
+
+		mem++;
+	}
+
+	return err;
+}
+
+/*
+ * Convert the hex array pointed to by buf into binary to be placed in mem.
+ * Return a pointer to the character AFTER the last byte written.
+ * May return an error.
+ */
+int kgdb_hex2mem(char *buf, char *mem, int count)
+{
+	char *tmp_raw;
+	char *tmp_hex;
+
+	/*
+	 * We use the upper half of buf as an intermediate buffer for the
+	 * raw memory that is converted from hex.
+	 */
+	tmp_raw = buf + count * 2;
+
+	tmp_hex = tmp_raw - 1;
+	while (tmp_hex >= buf) {
+		tmp_raw--;
+		*tmp_raw = hex(*tmp_hex--);
+		*tmp_raw |= hex(*tmp_hex--) << 4;
+	}
+
+	return probe_kernel_write(mem, tmp_raw, count);
+}
+
+/*
+ * While we find nice hex chars, build a long_val.
+ * Return number of chars processed.
+ */
+int kgdb_hex2long(char **ptr, long *long_val)
+{
+	int hex_val;
+	int num = 0;
+
+	*long_val = 0;
+
+	while (**ptr) {
+		hex_val = hex(**ptr);
+		if (hex_val < 0)
+			break;
+
+		*long_val = (*long_val << 4) | hex_val;
+		num++;
+		(*ptr)++;
+	}
+
+	return num;
+}
+
+/* Write memory due to an 'M' or 'X' packet. */
+static int write_mem_msg(int binary)
+{
+	char *ptr = &remcom_in_buffer[1];
+	unsigned long addr;
+	unsigned long length;
+	int err;
+
+	if (kgdb_hex2long(&ptr, &addr) > 0 && *(ptr++) == ',' &&
+	    kgdb_hex2long(&ptr, &length) > 0 && *(ptr++) == ':') {
+		if (binary)
+			err = kgdb_ebin2mem(ptr, (char *)addr, length);
+		else
+			err = kgdb_hex2mem(ptr, (char *)addr, length);
+		if (err)
+			return err;
+		if (CACHE_FLUSH_IS_SAFE)
+			flush_icache_range(addr, addr + length + 1);
+		return 0;
+	}
+
+	return -EINVAL;
+}
+
+static void error_packet(char *pkt, int error)
+{
+	error = -error;
+	pkt[0] = 'E';
+	pkt[1] = hexchars[(error / 10)];
+	pkt[2] = hexchars[(error % 10)];
+	pkt[3] = '\0';
+}
+
+/*
+ * Thread ID accessors. We represent a flat TID space to GDB, where
+ * the per CPU idle threads (which under Linux all have PID 0) are
+ * remapped to negative TIDs.
+ */
+
+#define BUF_THREAD_ID_SIZE	16
+
+static char *pack_threadid(char *pkt, unsigned char *id)
+{
+	char *limit;
+
+	limit = pkt + BUF_THREAD_ID_SIZE;
+	while (pkt < limit)
+		pkt = pack_hex_byte(pkt, *id++);
+
+	return pkt;
+}
+
+static void int_to_threadref(unsigned char *id, int value)
+{
+	unsigned char *scan;
+	int i = 4;
+
+	scan = (unsigned char *)id;
+	while (i--)
+		*scan++ = 0;
+	*scan++ = (value >> 24) & 0xff;
+	*scan++ = (value >> 16) & 0xff;
+	*scan++ = (value >> 8) & 0xff;
+	*scan++ = (value & 0xff);
+}
+
+static struct task_struct *getthread(struct pt_regs *regs, int tid)
+{
+	/*
+	 * Non-positive TIDs are remapped idle tasks:
+	 */
+	if (tid <= 0)
+		return idle_task(-tid);
+
+	/*
+	 * find_task_by_pid() does not take the tasklist lock anymore
+	 * but is nicely RCU locked - hence is a pretty resilient
+	 * thing to use:
+	 */
+	return find_task_by_pid(tid);
+}
+
+/*
+ * CPU debug state control:
+ */
+
+#ifdef CONFIG_SMP
+static void kgdb_wait(struct pt_regs *regs)
+{
+	unsigned long flags;
+	int cpu;
+
+	local_irq_save(flags);
+	cpu = raw_smp_processor_id();
+	kgdb_info[cpu].debuggerinfo = regs;
+	kgdb_info[cpu].task = current;
+	/*
+	 * Make sure the above info reaches the primary CPU before
+	 * our cpu_in_kgdb[] flag setting does:
+	 */
+	smp_wmb();
+	atomic_set(&cpu_in_kgdb[cpu], 1);
+
+	/*
+	 * The primary CPU must be active to enter here, but this is
+	 * guard in case the primary CPU had not been selected if
+	 * this was an entry via nmi.
+	 */
+	while (atomic_read(&kgdb_active) == -1)
+		cpu_relax();
+
+	/* Wait till primary CPU goes completely into the debugger. */
+	while (!atomic_read(&cpu_in_kgdb[atomic_read(&kgdb_active)]))
+		cpu_relax();
+
+	/* Wait till primary CPU is done with debugging */
+	while (atomic_read(&passive_cpu_wait[cpu]))
+		cpu_relax();
+
+	kgdb_info[cpu].debuggerinfo = NULL;
+	kgdb_info[cpu].task = NULL;
+
+	/* fix up hardware debug registers on local cpu */
+	if (arch_kgdb_ops.correct_hw_break)
+		arch_kgdb_ops.correct_hw_break();
+
+	/* Signal the primary CPU that we are done: */
+	atomic_set(&cpu_in_kgdb[cpu], 0);
+	clocksource_touch_watchdog();
+	local_irq_restore(flags);
+}
+#endif
+
+/*
+ * Some architectures need cache flushes when we set/clear a
+ * breakpoint:
+ */
+static void kgdb_flush_swbreak_addr(unsigned long addr)
+{
+	if (!CACHE_FLUSH_IS_SAFE)
+		return;
+
+	if (current->mm) {
+		flush_cache_range(current->mm->mmap_cache,
+				  addr, addr + BREAK_INSTR_SIZE);
+	} else {
+		flush_icache_range(addr, addr + BREAK_INSTR_SIZE);
+	}
+}
+
+/*
+ * SW breakpoint management:
+ */
+static int kgdb_activate_sw_breakpoints(void)
+{
+	unsigned long addr;
+	int error = 0;
+	int i;
+
+	for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+		if (kgdb_break[i].state != BP_SET)
+			continue;
+
+		addr = kgdb_break[i].bpt_addr;
+		error = kgdb_arch_set_breakpoint(addr,
+				kgdb_break[i].saved_instr);
+		if (error)
+			return error;
+
+		kgdb_flush_swbreak_addr(addr);
+		kgdb_break[i].state = BP_ACTIVE;
+	}
+	return 0;
+}
+
+static int kgdb_set_sw_break(unsigned long addr)
+{
+	int err = kgdb_validate_break_address(addr);
+	int breakno = -1;
+	int i;
+
+	if (err)
+		return err;
+
+	for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+		if ((kgdb_break[i].state == BP_SET) &&
+					(kgdb_break[i].bpt_addr == addr))
+			return -EEXIST;
+	}
+	for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+		if (kgdb_break[i].state == BP_REMOVED &&
+					kgdb_break[i].bpt_addr == addr) {
+			breakno = i;
+			break;
+		}
+	}
+
+	if (breakno == -1) {
+		for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+			if (kgdb_break[i].state == BP_UNDEFINED) {
+				breakno = i;
+				break;
+			}
+		}
+	}
+
+	if (breakno == -1)
+		return -E2BIG;
+
+	kgdb_break[breakno].state = BP_SET;
+	kgdb_break[breakno].type = BP_BREAKPOINT;
+	kgdb_break[breakno].bpt_addr = addr;
+
+	return 0;
+}
+
+static int kgdb_deactivate_sw_breakpoints(void)
+{
+	unsigned long addr;
+	int error = 0;
+	int i;
+
+	for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+		if (kgdb_break[i].state != BP_ACTIVE)
+			continue;
+		addr = kgdb_break[i].bpt_addr;
+		error = kgdb_arch_remove_breakpoint(addr,
+					kgdb_break[i].saved_instr);
+		if (error)
+			return error;
+
+		kgdb_flush_swbreak_addr(addr);
+		kgdb_break[i].state = BP_SET;
+	}
+	return 0;
+}
+
+static int kgdb_remove_sw_break(unsigned long addr)
+{
+	int i;
+
+	for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+		if ((kgdb_break[i].state == BP_SET) &&
+				(kgdb_break[i].bpt_addr == addr)) {
+			kgdb_break[i].state = BP_REMOVED;
+			return 0;
+		}
+	}
+	return -ENOENT;
+}
+
+int kgdb_isremovedbreak(unsigned long addr)
+{
+	int i;
+
+	for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+		if ((kgdb_break[i].state == BP_REMOVED) &&
+					(kgdb_break[i].bpt_addr == addr))
+			return 1;
+	}
+	return 0;
+}
+
+int remove_all_break(void)
+{
+	unsigned long addr;
+	int error;
+	int i;
+
+	/* Clear memory breakpoints. */
+	for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+		if (kgdb_break[i].state != BP_SET)
+			continue;
+		addr = kgdb_break[i].bpt_addr;
+		error = kgdb_arch_remove_breakpoint(addr,
+				kgdb_break[i].saved_instr);
+		if (error)
+			return error;
+		kgdb_break[i].state = BP_REMOVED;
+	}
+
+	/* Clear hardware breakpoints. */
+	if (arch_kgdb_ops.remove_all_hw_break)
+		arch_kgdb_ops.remove_all_hw_break();
+
+	return 0;
+}
+
+/*
+ * Remap normal tasks to their real PID, idle tasks to -1 ... -NR_CPUs:
+ */
+static inline int shadow_pid(int realpid)
+{
+	if (realpid)
+		return realpid;
+
+	return -1-raw_smp_processor_id();
+}
+
+static char gdbmsgbuf[BUFMAX + 1];
+
+static void kgdb_msg_write(const char *s, int len)
+{
+	char *bufptr;
+	int wcount;
+	int i;
+
+	/* 'O'utput */
+	gdbmsgbuf[0] = 'O';
+
+	/* Fill and send buffers... */
+	while (len > 0) {
+		bufptr = gdbmsgbuf + 1;
+
+		/* Calculate how many this time */
+		if ((len << 1) > (BUFMAX - 2))
+			wcount = (BUFMAX - 2) >> 1;
+		else
+			wcount = len;
+
+		/* Pack in hex chars */
+		for (i = 0; i < wcount; i++)
+			bufptr = pack_hex_byte(bufptr, s[i]);
+		*bufptr = '\0';
+
+		/* Move up */
+		s += wcount;
+		len -= wcount;
+
+		/* Write packet */
+		put_packet(gdbmsgbuf);
+	}
+}
+
+/*
+ * Return true if there is a valid kgdb I/O module.  Also if no
+ * debugger is attached a message can be printed to the console about
+ * waiting for the debugger to attach.
+ *
+ * The print_wait argument is only to be true when called from inside
+ * the core kgdb_handle_exception, because it will wait for the
+ * debugger to attach.
+ */
+static int kgdb_io_ready(int print_wait)
+{
+	if (!kgdb_io_ops)
+		return 0;
+	if (kgdb_connected)
+		return 1;
+	if (atomic_read(&kgdb_setting_breakpoint))
+		return 1;
+	if (print_wait)
+		printk(KERN_CRIT "KGDB: Waiting for remote debugger\n");
+	return 1;
+}
+
+/*
+ * All the functions that start with gdb_cmd are the various
+ * operations to implement the handlers for the gdbserial protocol
+ * where KGDB is communicating with an external debugger
+ */
+
+/* Handle the '?' status packets */
+static void gdb_cmd_status(struct kgdb_state *ks)
+{
+	/*
+	 * We know that this packet is only sent
+	 * during initial connect.  So to be safe,
+	 * we clear out our breakpoints now in case
+	 * GDB is reconnecting.
+	 */
+	remove_all_break();
+
+	remcom_out_buffer[0] = 'S';
+	pack_hex_byte(&remcom_out_buffer[1], ks->signo);
+}
+
+/* Handle the 'g' get registers request */
+static void gdb_cmd_getregs(struct kgdb_state *ks)
+{
+	struct task_struct *thread;
+	void *local_debuggerinfo;
+	int i;
+
+	thread = kgdb_usethread;
+	if (!thread) {
+		thread = kgdb_info[ks->cpu].task;
+		local_debuggerinfo = kgdb_info[ks->cpu].debuggerinfo;
+	} else {
+		local_debuggerinfo = NULL;
+		for (i = 0; i < NR_CPUS; i++) {
+			/*
+			 * Try to find the task on some other
+			 * or possibly this node if we do not
+			 * find the matching task then we try
+			 * to approximate the results.
+			 */
+			if (thread == kgdb_info[i].task)
+				local_debuggerinfo = kgdb_info[i].debuggerinfo;
+		}
+	}
+
+	/*
+	 * All threads that don't have debuggerinfo should be
+	 * in __schedule() sleeping, since all other CPUs
+	 * are in kgdb_wait, and thus have debuggerinfo.
+	 */
+	if (local_debuggerinfo) {
+		pt_regs_to_gdb_regs(gdb_regs, local_debuggerinfo);
+	} else {
+		/*
+		 * Pull stuff saved during switch_to; nothing
+		 * else is accessible (or even particularly
+		 * relevant).
+		 *
+		 * This should be enough for a stack trace.
+		 */
+		sleeping_thread_to_gdb_regs(gdb_regs, thread);
+	}
+	kgdb_mem2hex((char *)gdb_regs, remcom_out_buffer, NUMREGBYTES);
+}
+
+/* Handle the 'G' set registers request */
+static void gdb_cmd_setregs(struct kgdb_state *ks)
+{
+	kgdb_hex2mem(&remcom_in_buffer[1], (char *)gdb_regs, NUMREGBYTES);
+
+	if (kgdb_usethread && kgdb_usethread != current) {
+		error_packet(remcom_out_buffer, -EINVAL);
+	} else {
+		gdb_regs_to_pt_regs(gdb_regs, ks->linux_regs);
+		strcpy(remcom_out_buffer, "OK");
+	}
+}
+
+/* Handle the 'm' memory read bytes */
+static void gdb_cmd_memread(struct kgdb_state *ks)
+{
+	char *ptr = &remcom_in_buffer[1];
+	unsigned long length;
+	unsigned long addr;
+	int err;
+
+	if (kgdb_hex2long(&ptr, &addr) > 0 && *ptr++ == ',' &&
+					kgdb_hex2long(&ptr, &length) > 0) {
+		err = kgdb_mem2hex((char *)addr, remcom_out_buffer, length);
+		if (err)
+			error_packet(remcom_out_buffer, err);
+	} else {
+		error_packet(remcom_out_buffer, -EINVAL);
+	}
+}
+
+/* Handle the 'M' memory write bytes */
+static void gdb_cmd_memwrite(struct kgdb_state *ks)
+{
+	int err = write_mem_msg(0);
+
+	if (err)
+		error_packet(remcom_out_buffer, err);
+	else
+		strcpy(remcom_out_buffer, "OK");
+}
+
+/* Handle the 'X' memory binary write bytes */
+static void gdb_cmd_binwrite(struct kgdb_state *ks)
+{
+	int err = write_mem_msg(1);
+
+	if (err)
+		error_packet(remcom_out_buffer, err);
+	else
+		strcpy(remcom_out_buffer, "OK");
+}
+
+/* Handle the 'D' or 'k', detach or kill packets */
+static void gdb_cmd_detachkill(struct kgdb_state *ks)
+{
+	int error;
+
+	/* The detach case */
+	if (remcom_in_buffer[0] == 'D') {
+		error = remove_all_break();
+		if (error < 0) {
+			error_packet(remcom_out_buffer, error);
+		} else {
+			strcpy(remcom_out_buffer, "OK");
+			kgdb_connected = 0;
+		}
+		put_packet(remcom_out_buffer);
+	} else {
+		/*
+		 * Assume the kill case, with no exit code checking,
+		 * trying to force detach the debugger:
+		 */
+		remove_all_break();
+		kgdb_connected = 0;
+	}
+}
+
+/* Handle the 'R' reboot packets */
+static int gdb_cmd_reboot(struct kgdb_state *ks)
+{
+	/* For now, only honor R0 */
+	if (strcmp(remcom_in_buffer, "R0") == 0) {
+		printk(KERN_CRIT "Executing emergency reboot\n");
+		strcpy(remcom_out_buffer, "OK");
+		put_packet(remcom_out_buffer);
+
+		/*
+		 * Execution should not return from
+		 * machine_emergency_restart()
+		 */
+		machine_emergency_restart();
+		kgdb_connected = 0;
+
+		return 1;
+	}
+	return 0;
+}
+
+/* Handle the 'q' query packets */
+static void gdb_cmd_query(struct kgdb_state *ks)
+{
+	struct task_struct *thread;
+	unsigned char thref[8];
+	char *ptr;
+	int i;
+
+	switch (remcom_in_buffer[1]) {
+	case 's':
+	case 'f':
+		if (memcmp(remcom_in_buffer + 2, "ThreadInfo", 10)) {
+			error_packet(remcom_out_buffer, -EINVAL);
+			break;
+		}
+
+		if (remcom_in_buffer[1] == 'f')
+			ks->threadid = 1;
+
+		remcom_out_buffer[0] = 'm';
+		ptr = remcom_out_buffer + 1;
+
+		for (i = 0; i < 17; ks->threadid++) {
+			thread = getthread(ks->linux_regs, ks->threadid);
+			if (thread) {
+				int_to_threadref(thref, ks->threadid);
+				pack_threadid(ptr, thref);
+				ptr += BUF_THREAD_ID_SIZE;
+				*(ptr++) = ',';
+				i++;
+			}
+		}
+		*(--ptr) = '\0';
+		break;
+
+	case 'C':
+		/* Current thread id */
+		strcpy(remcom_out_buffer, "QC");
+		ks->threadid = shadow_pid(current->pid);
+		int_to_threadref(thref, ks->threadid);
+		pack_threadid(remcom_out_buffer + 2, thref);
+		break;
+	case 'T':
+		if (memcmp(remcom_in_buffer + 1, "ThreadExtraInfo,", 16)) {
+			error_packet(remcom_out_buffer, -EINVAL);
+			break;
+		}
+		ks->threadid = 0;
+		ptr = remcom_in_buffer + 17;
+		kgdb_hex2long(&ptr, &ks->threadid);
+		if (!getthread(ks->linux_regs, ks->threadid)) {
+			error_packet(remcom_out_buffer, -EINVAL);
+			break;
+		}
+		if (ks->threadid > 0) {
+			kgdb_mem2hex(getthread(ks->linux_regs,
+					ks->threadid)->comm,
+					remcom_out_buffer, 16);
+		} else {
+			static char tmpstr[23 + BUF_THREAD_ID_SIZE];
+
+			sprintf(tmpstr, "Shadow task %d for pid 0",
+					(int)(-ks->threadid-1));
+			kgdb_mem2hex(tmpstr, remcom_out_buffer, strlen(tmpstr));
+		}
+		break;
+	}
+}
+
+/* Handle the 'H' task query packets */
+static void gdb_cmd_task(struct kgdb_state *ks)
+{
+	struct task_struct *thread;
+	char *ptr;
+
+	switch (remcom_in_buffer[1]) {
+	case 'g':
+		ptr = &remcom_in_buffer[2];
+		kgdb_hex2long(&ptr, &ks->threadid);
+		thread = getthread(ks->linux_regs, ks->threadid);
+		if (!thread && ks->threadid > 0) {
+			error_packet(remcom_out_buffer, -EINVAL);
+			break;
+		}
+		kgdb_usethread = thread;
+		ks->kgdb_usethreadid = ks->threadid;
+		strcpy(remcom_out_buffer, "OK");
+		break;
+	case 'c':
+		ptr = &remcom_in_buffer[2];
+		kgdb_hex2long(&ptr, &ks->threadid);
+		if (!ks->threadid) {
+			kgdb_contthread = NULL;
+		} else {
+			thread = getthread(ks->linux_regs, ks->threadid);
+			if (!thread && ks->threadid > 0) {
+				error_packet(remcom_out_buffer, -EINVAL);
+				break;
+			}
+			kgdb_contthread = thread;
+		}
+		strcpy(remcom_out_buffer, "OK");
+		break;
+	}
+}
+
+/* Handle the 'T' thread query packets */
+static void gdb_cmd_thread(struct kgdb_state *ks)
+{
+	char *ptr = &remcom_in_buffer[1];
+	struct task_struct *thread;
+
+	kgdb_hex2long(&ptr, &ks->threadid);
+	thread = getthread(ks->linux_regs, ks->threadid);
+	if (thread)
+		strcpy(remcom_out_buffer, "OK");
+	else
+		error_packet(remcom_out_buffer, -EINVAL);
+}
+
+/* Handle the 'z' or 'Z' breakpoint remove or set packets */
+static void gdb_cmd_break(struct kgdb_state *ks)
+{
+	/*
+	 * Since GDB-5.3, it's been drafted that '0' is a software
+	 * breakpoint, '1' is a hardware breakpoint, so let's do that.
+	 */
+	char *bpt_type = &remcom_in_buffer[1];
+	char *ptr = &remcom_in_buffer[2];
+	unsigned long addr;
+	unsigned long length;
+	int error = 0;
+
+	if (arch_kgdb_ops.set_hw_breakpoint && *bpt_type >= '1') {
+		/* Unsupported */
+		if (*bpt_type > '4')
+			return;
+	} else {
+		if (*bpt_type != '0' && *bpt_type != '1')
+			/* Unsupported. */
+			return;
+	}
+
+	/*
+	 * Test if this is a hardware breakpoint, and
+	 * if we support it:
+	 */
+	if (*bpt_type == '1' && !(arch_kgdb_ops.flags & KGDB_HW_BREAKPOINT))
+		/* Unsupported. */
+		return;
+
+	if (*(ptr++) != ',') {
+		error_packet(remcom_out_buffer, -EINVAL);
+		return;
+	}
+	if (!kgdb_hex2long(&ptr, &addr)) {
+		error_packet(remcom_out_buffer, -EINVAL);
+		return;
+	}
+	if (*(ptr++) != ',' ||
+		!kgdb_hex2long(&ptr, &length)) {
+		error_packet(remcom_out_buffer, -EINVAL);
+		return;
+	}
+
+	if (remcom_in_buffer[0] == 'Z' && *bpt_type == '0')
+		error = kgdb_set_sw_break(addr);
+	else if (remcom_in_buffer[0] == 'z' && *bpt_type == '0')
+		error = kgdb_remove_sw_break(addr);
+	else if (remcom_in_buffer[0] == 'Z')
+		error = arch_kgdb_ops.set_hw_breakpoint(addr,
+			(int)length, *bpt_type - '0');
+	else if (remcom_in_buffer[0] == 'z')
+		error = arch_kgdb_ops.remove_hw_breakpoint(addr,
+			(int) length, *bpt_type - '0');
+
+	if (error == 0)
+		strcpy(remcom_out_buffer, "OK");
+	else
+		error_packet(remcom_out_buffer, error);
+}
+
+/* Handle the 'C' signal / exception passing packets */
+static int gdb_cmd_exception_pass(struct kgdb_state *ks)
+{
+	/* C09 == pass exception
+	 * C15 == detach kgdb, pass exception
+	 */
+	if (remcom_in_buffer[1] == '0' && remcom_in_buffer[2] == '9') {
+
+		ks->pass_exception = 1;
+		remcom_in_buffer[0] = 'c';
+
+	} else if (remcom_in_buffer[1] == '1' && remcom_in_buffer[2] == '5') {
+
+		ks->pass_exception = 1;
+		remcom_in_buffer[0] = 'D';
+		remove_all_break();
+		kgdb_connected = 0;
+		return 1;
+
+	} else {
+		error_packet(remcom_out_buffer, -EINVAL);
+		return 0;
+	}
+
+	/* Indicate fall through */
+	return -1;
+}
+
+/*
+ * This function performs all gdbserial command procesing
+ */
+static int gdb_serial_stub(struct kgdb_state *ks)
+{
+	int error = 0;
+	int tmp;
+
+	/* Clear the out buffer. */
+	memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer));
+
+	if (kgdb_connected) {
+		unsigned char thref[8];
+		char *ptr;
+
+		/* Reply to host that an exception has occurred */
+		ptr = remcom_out_buffer;
+		*ptr++ = 'T';
+		ptr = pack_hex_byte(ptr, ks->signo);
+		ptr += strlen(strcpy(ptr, "thread:"));
+		int_to_threadref(thref, shadow_pid(current->pid));
+		ptr = pack_threadid(ptr, thref);
+		*ptr++ = ';';
+		put_packet(remcom_out_buffer);
+	}
+
+	kgdb_usethread = kgdb_info[ks->cpu].task;
+	ks->kgdb_usethreadid = shadow_pid(kgdb_info[ks->cpu].task->pid);
+	ks->pass_exception = 0;
+
+	while (1) {
+		error = 0;
+
+		/* Clear the out buffer. */
+		memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer));
+
+		get_packet(remcom_in_buffer);
+
+		switch (remcom_in_buffer[0]) {
+		case '?': /* gdbserial status */
+			gdb_cmd_status(ks);
+			break;
+		case 'g': /* return the value of the CPU registers */
+			gdb_cmd_getregs(ks);
+			break;
+		case 'G': /* set the value of the CPU registers - return OK */
+			gdb_cmd_setregs(ks);
+			break;
+		case 'm': /* mAA..AA,LLLL  Read LLLL bytes at address AA..AA */
+			gdb_cmd_memread(ks);
+			break;
+		case 'M': /* MAA..AA,LLLL: Write LLLL bytes at address AA..AA */
+			gdb_cmd_memwrite(ks);
+			break;
+		case 'X': /* XAA..AA,LLLL: Write LLLL bytes at address AA..AA */
+			gdb_cmd_binwrite(ks);
+			break;
+			/* kill or detach. KGDB should treat this like a
+			 * continue.
+			 */
+		case 'D': /* Debugger detach */
+		case 'k': /* Debugger detach via kill */
+			gdb_cmd_detachkill(ks);
+			goto default_handle;
+		case 'R': /* Reboot */
+			if (gdb_cmd_reboot(ks))
+				goto default_handle;
+			break;
+		case 'q': /* query command */
+			gdb_cmd_query(ks);
+			break;
+		case 'H': /* task related */
+			gdb_cmd_task(ks);
+			break;
+		case 'T': /* Query thread status */
+			gdb_cmd_thread(ks);
+			break;
+		case 'z': /* Break point remove */
+		case 'Z': /* Break point set */
+			gdb_cmd_break(ks);
+			break;
+		case 'C': /* Exception passing */
+			tmp = gdb_cmd_exception_pass(ks);
+			if (tmp > 0)
+				goto default_handle;
+			if (tmp == 0)
+				break;
+			/* Fall through on tmp < 0 */
+		case 'c': /* Continue packet */
+		case 's': /* Single step packet */
+			if (kgdb_contthread && kgdb_contthread != current) {
+				/* Can't switch threads in kgdb */
+				error_packet(remcom_out_buffer, -EINVAL);
+				break;
+			}
+			kgdb_activate_sw_breakpoints();
+			/* Fall through to default processing */
+		default:
+default_handle:
+			error = kgdb_arch_handle_exception(ks->ex_vector,
+						ks->signo,
+						ks->err_code,
+						remcom_in_buffer,
+						remcom_out_buffer,
+						ks->linux_regs);
+			/*
+			 * Leave cmd processing on error, detach,
+			 * kill, continue, or single step.
+			 */
+			if (error >= 0 || remcom_in_buffer[0] == 'D' ||
+			    remcom_in_buffer[0] == 'k') {
+				error = 0;
+				goto kgdb_exit;
+			}
+
+		}
+
+		/* reply to the request */
+		put_packet(remcom_out_buffer);
+	}
+
+kgdb_exit:
+	if (ks->pass_exception)
+		error = 1;
+	return error;
+}
+
+static int kgdb_reenter_check(struct kgdb_state *ks)
+{
+	unsigned long addr;
+
+	if (atomic_read(&kgdb_active) != raw_smp_processor_id())
+		return 0;
+
+	/* Panic on recursive debugger calls: */
+	exception_level++;
+	addr = kgdb_arch_pc(ks->ex_vector, ks->linux_regs);
+	kgdb_deactivate_sw_breakpoints();
+
+	/*
+	 * If the break point removed ok at the place exception
+	 * occurred, try to recover and print a warning to the end
+	 * user because the user planted a breakpoint in a place that
+	 * KGDB needs in order to function.
+	 */
+	if (kgdb_remove_sw_break(addr) == 0) {
+		exception_level = 0;
+		kgdb_skipexception(ks->ex_vector, ks->linux_regs);
+		kgdb_activate_sw_breakpoints();
+		printk(KERN_CRIT "KGDB: re-enter error: breakpoint removed %lx\n",
+			addr);
+		WARN_ON_ONCE(1);
+
+		return 1;
+	}
+	remove_all_break();
+	kgdb_skipexception(ks->ex_vector, ks->linux_regs);
+
+	if (exception_level > 1) {
+		dump_stack();
+		panic("Recursive entry to debugger");
+	}
+
+	printk(KERN_CRIT "KGDB: re-enter exception: ALL breakpoints killed\n");
+	dump_stack();
+	panic("Recursive entry to debugger");
+
+	return 1;
+}
+
+/*
+ * kgdb_handle_exception() - main entry point from a kernel exception
+ *
+ * Locking hierarchy:
+ *	interface locks, if any (begin_session)
+ *	kgdb lock (kgdb_active)
+ */
+int
+kgdb_handle_exception(int evector, int signo, int ecode, struct pt_regs *regs)
+{
+	struct kgdb_state kgdb_var;
+	struct kgdb_state *ks = &kgdb_var;
+	unsigned long flags;
+	int error = 0;
+	int i, cpu;
+
+	ks->cpu			= raw_smp_processor_id();
+	ks->ex_vector		= evector;
+	ks->signo		= signo;
+	ks->ex_vector		= evector;
+	ks->err_code		= ecode;
+	ks->kgdb_usethreadid	= 0;
+	ks->linux_regs		= regs;
+
+	if (kgdb_reenter_check(ks))
+		return 0; /* Ouch, double exception ! */
+
+acquirelock:
+	/*
+	 * Interrupts will be restored by the 'trap return' code, except when
+	 * single stepping.
+	 */
+	local_irq_save(flags);
+
+	cpu = raw_smp_processor_id();
+
+	/*
+	 * Acquire the kgdb_active lock:
+	 */
+	while (atomic_cmpxchg(&kgdb_active, -1, cpu) != -1)
+		cpu_relax();
+
+	/*
+	 * Do not start the debugger connection on this CPU if the last
+	 * instance of the exception handler wanted to come into the
+	 * debugger on a different CPU via a single step
+	 */
+	if (atomic_read(&kgdb_cpu_doing_single_step) != -1 &&
+	    atomic_read(&kgdb_cpu_doing_single_step) != cpu) {
+
+		atomic_set(&kgdb_active, -1);
+		clocksource_touch_watchdog();
+		local_irq_restore(flags);
+
+		goto acquirelock;
+	}
+
+	if (!kgdb_io_ready(1)) {
+		error = 1;
+		goto kgdb_restore; /* No I/O connection, so resume the system */
+	}
+
+	/*
+	 * Don't enter if we have hit a removed breakpoint.
+	 */
+	if (kgdb_skipexception(ks->ex_vector, ks->linux_regs))
+		goto kgdb_restore;
+
+	/* Call the I/O driver's pre_exception routine */
+	if (kgdb_io_ops->pre_exception)
+		kgdb_io_ops->pre_exception();
+
+	kgdb_info[ks->cpu].debuggerinfo = ks->linux_regs;
+	kgdb_info[ks->cpu].task = current;
+
+	kgdb_disable_hw_debug(ks->linux_regs);
+
+	/*
+	 * Get the passive CPU lock which will hold all the non-primary
+	 * CPU in a spin state while the debugger is active
+	 */
+	if (!kgdb_single_step || !kgdb_contthread) {
+		for (i = 0; i < NR_CPUS; i++)
+			atomic_set(&passive_cpu_wait[i], 1);
+	}
+
+#ifdef CONFIG_SMP
+	/* Signal the other CPUs to enter kgdb_wait() */
+	if (!kgdb_single_step || !kgdb_contthread)
+		kgdb_roundup_cpus(flags);
+#endif
+
+	/*
+	 * spin_lock code is good enough as a barrier so we don't
+	 * need one here:
+	 */
+	atomic_set(&cpu_in_kgdb[ks->cpu], 1);
+
+	/*
+	 * Wait for the other CPUs to be notified and be waiting for us:
+	 */
+	for_each_online_cpu(i) {
+		while (!atomic_read(&cpu_in_kgdb[i]))
+			cpu_relax();
+	}
+
+	/*
+	 * At this point the primary processor is completely
+	 * in the debugger and all secondary CPUs are quiescent
+	 */
+	kgdb_post_primary_code(ks->linux_regs, ks->ex_vector, ks->err_code);
+	kgdb_deactivate_sw_breakpoints();
+	kgdb_single_step = 0;
+	kgdb_contthread = NULL;
+	exception_level = 0;
+
+	/* Talk to debugger with gdbserial protocol */
+	error = gdb_serial_stub(ks);
+
+	/* Call the I/O driver's post_exception routine */
+	if (kgdb_io_ops->post_exception)
+		kgdb_io_ops->post_exception();
+
+	kgdb_info[ks->cpu].debuggerinfo = NULL;
+	kgdb_info[ks->cpu].task = NULL;
+	atomic_set(&cpu_in_kgdb[ks->cpu], 0);
+
+	if (!kgdb_single_step || !kgdb_contthread) {
+		for (i = NR_CPUS-1; i >= 0; i--)
+			atomic_set(&passive_cpu_wait[i], 0);
+		/*
+		 * Wait till all the CPUs have quit
+		 * from the debugger.
+		 */
+		for_each_online_cpu(i) {
+			while (atomic_read(&cpu_in_kgdb[i]))
+				cpu_relax();
+		}
+	}
+
+kgdb_restore:
+	/* Free kgdb_active */
+	atomic_set(&kgdb_active, -1);
+	clocksource_touch_watchdog();
+	local_irq_restore(flags);
+
+	return error;
+}
+
+int kgdb_nmicallback(int cpu, void *regs)
+{
+#ifdef CONFIG_SMP
+	if (!atomic_read(&cpu_in_kgdb[cpu]) &&
+			atomic_read(&kgdb_active) != cpu) {
+		kgdb_wait((struct pt_regs *)regs);
+		return 0;
+	}
+#endif
+	return 1;
+}
+
+void kgdb_console_write(struct console *co, const char *s, unsigned count)
+{
+	unsigned long flags;
+
+	/* If we're debugging, or KGDB has not connected, don't try
+	 * and print. */
+	if (!kgdb_connected || atomic_read(&kgdb_active) != -1)
+		return;
+
+	local_irq_save(flags);
+	kgdb_msg_write(s, count);
+	local_irq_restore(flags);
+}
+
+static struct console kgdbcons = {
+	.name		= "kgdb",
+	.write		= kgdb_console_write,
+	.flags		= CON_PRINTBUFFER | CON_ENABLED,
+	.index		= -1,
+};
+
+#ifdef CONFIG_MAGIC_SYSRQ
+static void sysrq_handle_gdb(int key, struct tty_struct *tty)
+{
+	if (!kgdb_io_ops) {
+		printk(KERN_CRIT "ERROR: No KGDB I/O module available\n");
+		return;
+	}
+	if (!kgdb_connected)
+		printk(KERN_CRIT "Entering KGDB\n");
+
+	kgdb_breakpoint();
+}
+
+static struct sysrq_key_op sysrq_gdb_op = {
+	.handler	= sysrq_handle_gdb,
+	.help_msg	= "Gdb",
+	.action_msg	= "GDB",
+};
+#endif
+
+static void kgdb_register_callbacks(void)
+{
+	if (!kgdb_io_module_registered) {
+		kgdb_io_module_registered = 1;
+		kgdb_arch_init();
+#ifdef CONFIG_MAGIC_SYSRQ
+		register_sysrq_key('g', &sysrq_gdb_op);
+#endif
+		if (kgdb_use_con && !kgdb_con_registered) {
+			register_console(&kgdbcons);
+			kgdb_con_registered = 1;
+		}
+	}
+}
+
+static void kgdb_unregister_callbacks(void)
+{
+	/*
+	 * When this routine is called KGDB should unregister from the
+	 * panic handler and clean up, making sure it is not handling any
+	 * break exceptions at the time.
+	 */
+	if (kgdb_io_module_registered) {
+		kgdb_io_module_registered = 0;
+		kgdb_arch_exit();
+#ifdef CONFIG_MAGIC_SYSRQ
+		unregister_sysrq_key('g', &sysrq_gdb_op);
+#endif
+		if (kgdb_con_registered) {
+			unregister_console(&kgdbcons);
+			kgdb_con_registered = 0;
+		}
+	}
+}
+
+static void kgdb_initial_breakpoint(void)
+{
+	kgdb_break_asap = 0;
+
+	printk(KERN_CRIT "kgdb: Waiting for connection from remote gdb...\n");
+	kgdb_breakpoint();
+}
+
+/**
+ *	kkgdb_register_io_module - register KGDB IO module
+ *	@new_kgdb_io_ops: the io ops vector
+ *
+ *	Register it with the KGDB core.
+ */
+int kgdb_register_io_module(struct kgdb_io *new_kgdb_io_ops)
+{
+	int err;
+
+	spin_lock(&kgdb_registration_lock);
+
+	if (kgdb_io_ops) {
+		spin_unlock(&kgdb_registration_lock);
+
+		printk(KERN_ERR "kgdb: Another I/O driver is already "
+				"registered with KGDB.\n");
+		return -EBUSY;
+	}
+
+	if (new_kgdb_io_ops->init) {
+		err = new_kgdb_io_ops->init();
+		if (err) {
+			spin_unlock(&kgdb_registration_lock);
+			return err;
+		}
+	}
+
+	kgdb_io_ops = new_kgdb_io_ops;
+
+	spin_unlock(&kgdb_registration_lock);
+
+	printk(KERN_INFO "kgdb: Registered I/O driver %s.\n",
+	       new_kgdb_io_ops->name);
+
+	/* Arm KGDB now. */
+	kgdb_register_callbacks();
+
+	if (kgdb_break_asap)
+		kgdb_initial_breakpoint();
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(kgdb_register_io_module);
+
+/**
+ *	kkgdb_unregister_io_module - unregister KGDB IO module
+ *	@old_kgdb_io_ops: the io ops vector
+ *
+ *	Unregister it with the KGDB core.
+ */
+void kgdb_unregister_io_module(struct kgdb_io *old_kgdb_io_ops)
+{
+	BUG_ON(kgdb_connected);
+
+	/*
+	 * KGDB is no longer able to communicate out, so
+	 * unregister our callbacks and reset state.
+	 */
+	kgdb_unregister_callbacks();
+
+	spin_lock(&kgdb_registration_lock);
+
+	WARN_ON_ONCE(kgdb_io_ops != old_kgdb_io_ops);
+	kgdb_io_ops = NULL;
+
+	spin_unlock(&kgdb_registration_lock);
+
+	printk(KERN_INFO
+		"kgdb: Unregistered I/O driver %s, debugger disabled.\n",
+		old_kgdb_io_ops->name);
+}
+EXPORT_SYMBOL_GPL(kgdb_unregister_io_module);
+
+/**
+ * kgdb_breakpoint - generate breakpoint exception
+ *
+ * This function will generate a breakpoint exception.  It is used at the
+ * beginning of a program to sync up with a debugger and can be used
+ * otherwise as a quick means to stop program execution and "break" into
+ * the debugger.
+ */
+void kgdb_breakpoint(void)
+{
+	atomic_set(&kgdb_setting_breakpoint, 1);
+	wmb(); /* Sync point before breakpoint */
+	arch_kgdb_breakpoint();
+	wmb(); /* Sync point after breakpoint */
+	atomic_set(&kgdb_setting_breakpoint, 0);
+}
+EXPORT_SYMBOL_GPL(kgdb_breakpoint);
+
+static int __init opt_kgdb_wait(char *str)
+{
+	kgdb_break_asap = 1;
+
+	if (kgdb_io_module_registered)
+		kgdb_initial_breakpoint();
+
+	return 0;
+}
+
+early_param("kgdbwait", opt_kgdb_wait);
-- 
1.5.4

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