[PATCH][1/6] A different KGDB stub

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* [PATCH][1/6] A different KGDB stub
@ 2004-02-17 22:02 Tom Rini
  2004-02-17 23:50 ` Andrew Morton
  2004-02-18 19:36 ` Pavel Machek
  0 siblings, 2 replies; 9+ messages in thread
From: Tom Rini @ 2004-02-17 22:02 UTC (permalink / raw)
  To: Andrew Morton, Kernel Mailing List

The following is the core bits to this KGDB stub.

 Makefile                 |    2 
 drivers/char/sysrq.c     |   22 
 include/linux/debugger.h |   72 ++
 include/linux/kgdb.h     |  127 ++++
 include/linux/sched.h    |   13 
 init/main.c              |    2 
 kernel/Kconfig.kgdb      |  141 +++++
 kernel/Makefile          |    1 
 kernel/kgdbstub.c        | 1300 +++++++++++++++++++++++++++++++++++++++++++++++
 kernel/module.c          |   10 
 kernel/sched.c           |   22 
 11 files changed, 1709 insertions(+), 3 deletions(-)
--- linux-2.6.3-rc4/Makefile	2004-02-17 09:53:13.000000000 -0700
+++ linux-2.6.3-rc4-kgdb/Makefile	2004-02-17 11:34:07.454848329 -0700
@@ -440,6 +440,8 @@ endif
 
 ifndef CONFIG_FRAME_POINTER
 CFLAGS		+= -fomit-frame-pointer
+else
+CFLAGS		+= -fno-omit-frame-pointer
 endif
 
 ifdef CONFIG_DEBUG_INFO
--- linux-2.6.3-rc4/drivers/char/sysrq.c	2004-02-17 09:53:54.000000000 -0700
+++ linux-2.6.3-rc4-kgdb/drivers/char/sysrq.c	2004-02-17 11:34:22.042537555 -0700
@@ -31,6 +31,7 @@
 #include <linux/suspend.h>
 #include <linux/writeback.h>
 #include <linux/buffer_head.h>		/* for fsync_bdev() */
+#include <linux/kgdb.h>			/* for breakpoint() */
 
 #include <linux/spinlock.h>
 
@@ -44,6 +45,25 @@ int sysrq_enabled = 1;
 /* Machine specific power off function */
 void (*sysrq_power_off)(void);
 
+/* Make a breakpoint() right now. */
+#ifdef CONFIG_KGDB
+#define  GDB_OP &kgdb_op
+static void kgdb_sysrq(int key, struct pt_regs *pt_regs, struct tty_struct *tty)
+{
+	printk("kgdb sysrq\n");
+	breakpoint();
+}
+
+static struct sysrq_key_op kgdb_op = {
+	.handler	= kgdb_sysrq,
+	.help_msg	= "kGdb|Fgdb",
+	.action_msg	= "Debug breakpoint\n",
+};
+
+#else
+#define  GDB_OP NULL
+#endif
+
 /* Loglevel sysrq handler */
 static void sysrq_handle_loglevel(int key, struct pt_regs *pt_regs,
 				  struct tty_struct *tty) 
@@ -239,7 +259,7 @@ static struct sysrq_key_op *sysrq_key_ta
 /* d */	NULL,
 /* e */	&sysrq_term_op,
 /* f */	NULL,
-/* g */	NULL,
+/* g */	GDB_OP,
 /* h */	NULL,
 /* i */	&sysrq_kill_op,
 /* j */	NULL,
--- linux-2.6.3-rc4/include/linux/debugger.h	1969-12-31 17:00:00.000000000 -0700
+++ linux-2.6.3-rc4-kgdb/include/linux/debugger.h	2004-02-17 11:34:22.828359208 -0700
@@ -0,0 +1,72 @@
+#ifndef _DEBUGGER_H_
+#define _DEBUGGER_H_
+
+/*
+ * Copyright (C) 2003-2004 Amit S. Kale
+ *
+ * Definition switchout for debuggers
+ */
+
+/*
+ * KGDB
+ */
+#ifdef CONFIG_KGDB
+
+typedef int gdb_debug_hook(int exVector, int signo, int err_code,
+                            struct pt_regs *regs);
+extern gdb_debug_hook  *linux_debug_hook;
+#define	CHK_DEBUGGER(trapnr,signr,error_code,regs,after)			\
+    {									\
+	if (linux_debug_hook != (gdb_debug_hook *) NULL && !user_mode(regs)) \
+	{								\
+		(*linux_debug_hook)(trapnr, signr, error_code, regs) ;	\
+		after;							\
+	}								\
+    }
+
+void kgdb_nmihook(int cpu, void *regs);
+static inline void debugger_nmihook(int cpu, void *regs)
+{
+	kgdb_nmihook(cpu, regs);
+}
+
+void kgdb_entry(void);
+static inline void debugger_entry(void)
+{
+	kgdb_entry();
+}
+
+extern int debugger_step;
+extern atomic_t debugger_active;
+extern volatile int debugger_memerr_expected;
+
+/*
+ * No debugger in the kernel
+ */
+#else
+
+#define	CHK_DEBUGGER(trapnr,signr,error_code,regs,after)	\
+{								\
+	if (0)							\
+		after;						\
+}
+
+
+static inline void debugger_nmihook(int cpu, void *regs)
+{
+	/* Do nothing */
+}
+
+static inline void debugger_entry(void)
+{
+	/* Do nothing */
+}
+
+#define debugger_step 0
+static const atomic_t debugger_active = { 0 };
+#define debugger_memerr_expected 0
+
+#endif
+
+
+#endif /* _DEBUGGER_H_ */
--- linux-2.6.3-rc4/include/linux/kgdb.h	1969-12-31 17:00:00.000000000 -0700
+++ linux-2.6.3-rc4-kgdb/include/linux/kgdb.h	2004-02-17 11:33:51.575452295 -0700
@@ -0,0 +1,127 @@
+#ifndef _KGDB_H_
+#define _KGDB_H_
+
+/*
+ * Copyright (C) 2001-2004 Amit S. Kale
+ */
+
+#include <linux/ptrace.h>
+#include <asm/kgdb.h>
+#include <linux/spinlock.h>
+#include <asm/atomic.h>
+#include <linux/debugger.h>
+
+/*
+ * This file should not include ANY others.  This makes it usable
+ * most anywhere without the fear of include order or inclusion.
+ * TODO: Make it so!
+ *
+ * This file may be included all the time.  It is only active if
+ * CONFIG_KGDB is defined, otherwise it stubs out all the macros
+ * and entry points.
+ */
+
+#if defined(CONFIG_KGDB) && !defined(__ASSEMBLY__)
+/* To enter the debugger explicitly. */
+extern void breakpoint(void);
+extern void kgdb_schedule_breakpoint(void);
+extern void kgdb_process_breakpoint(void);
+extern volatile int kgdb_connected;
+
+extern atomic_t kgdb_setting_breakpoint;
+extern atomic_t debugger_active;
+
+#ifndef KGDB_MAX_NO_CPUS
+#if CONFIG_NR_CPUS > 8
+#error KGDB can handle max 8 CPUs
+#endif
+#define KGDB_MAX_NO_CPUS 8
+#endif
+
+
+extern struct task_struct *kgdb_usethread, *kgdb_contthread;
+
+enum gdb_bptype
+{
+	bp_breakpoint = '0',
+	bp_hardware_breakpoint,
+	bp_write_watchpoint,
+	bp_read_watchpoint,
+	bp_access_watchpoint
+};
+
+enum gdb_bpstate
+{
+       bp_disabled,
+       bp_enabled
+};
+
+#ifndef BREAK_INSTR_SIZE
+#error BREAK_INSTR_SIZE  needed by kgdb
+#endif
+
+struct gdb_breakpoint
+{
+       unsigned long            bpt_addr;
+       unsigned char           saved_instr[BREAK_INSTR_SIZE];
+       enum gdb_bptype         type;
+       enum gdb_bpstate        state;
+};
+
+typedef struct gdb_breakpoint gdb_breakpoint_t;
+
+#ifndef MAX_BREAKPOINTS
+#define MAX_BREAKPOINTS        16
+#endif
+
+#define KGDB_HW_BREAKPOINT          1
+
+/* These are functions that the arch specific code can, and in some cases
+ * must, provide. */
+extern int kgdb_arch_init(void);
+extern void regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs);
+extern void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs,struct task_struct *p);
+extern void gdb_regs_to_regs(unsigned long *gdb_regs, struct pt_regs *regs);
+extern void kgdb_printexceptioninfo(int exceptionNo, int errorcode,
+		char *buffer);
+extern void kgdb_disable_hw_debug(struct pt_regs *regs);
+extern void kgdb_post_master_code(struct pt_regs *regs, int eVector,
+		int err_code);
+extern int kgdb_arch_handle_exception(int vector, int signo, int err_code,
+		char *InBuffer, char *outBuffer, struct pt_regs *regs);
+extern int kgdb_arch_set_break(unsigned long addr, int type);
+extern int kgdb_arch_remove_break(unsigned long addr, int type);
+extern void kgdb_correct_hw_break(void);
+extern void kgdb_shadowinfo(struct pt_regs *regs, char *buffer, unsigned threadid);
+extern struct task_struct *kgdb_get_shadow_thread(struct pt_regs *regs,
+		int threadid);
+extern struct pt_regs *kgdb_shadow_regs(struct pt_regs *regs, int threadid);
+
+struct kgdb_arch {
+	unsigned char gdb_bpt_instr[BREAK_INSTR_SIZE];
+	unsigned long flags;
+	unsigned shadowth;
+};			
+
+/* Thread reference */
+typedef unsigned char threadref[8];
+
+extern int kgdb_get_debug_char(void);
+extern void kgdb_put_debug_char(int ch);
+extern void kgdb_flush_debug_char(void);
+extern int kgdb_hook_io(void);
+
+extern struct kgdb_arch arch_kgdb_ops;
+extern int kgdb_initialized;
+
+struct uart_port;
+
+extern void kgdb8250_add_port(int i, struct uart_port *serial_req);
+
+int kgdb_hex2long(char **ptr, long *longValue);
+char *kgdb_mem2hex(char *mem, char *buf, int count, int can_fault);
+
+#else
+#define kgdb_process_breakpoint()	do {} while(0)
+#endif /* KGDB && !__ASSEMBLY__ */
+#endif /* _KGDB_H_ */
--- linux-2.6.3-rc4/include/linux/sched.h	2004-02-17 09:51:05.000000000 -0700
+++ linux-2.6.3-rc4-kgdb/include/linux/sched.h	2004-02-17 11:33:49.531916096 -0700
@@ -173,7 +173,9 @@ extern unsigned long cache_decay_ticks;
 
 #define	MAX_SCHEDULE_TIMEOUT	LONG_MAX
 extern signed long FASTCALL(schedule_timeout(signed long timeout));
-asmlinkage void schedule(void);
+asmlinkage void do_schedule(void);
+asmlinkage void kern_schedule(void);
+asmlinkage void kern_do_schedule(struct pt_regs);
 
 struct namespace;
 
@@ -907,6 +909,15 @@ static inline void set_task_cpu(struct t
 
 #endif /* CONFIG_SMP */
 
+static inline void schedule(void)
+{
+#ifdef CONFIG_KGDB_THREAD
+	kern_schedule();
+#else
+	do_schedule();
+#endif
+}
+
 #endif /* __KERNEL__ */
 
 #endif
--- linux-2.6.3-rc4/init/main.c	2004-02-17 09:51:19.000000000 -0700
+++ linux-2.6.3-rc4-kgdb/init/main.c	2004-02-17 11:33:51.854388988 -0700
@@ -39,6 +39,7 @@
 #include <linux/writeback.h>
 #include <linux/cpu.h>
 #include <linux/efi.h>
+#include <linux/debugger.h>
 
 #include <asm/io.h>
 #include <asm/bugs.h>
@@ -581,6 +582,7 @@ static int init(void * unused)
 
 	smp_init();
 	do_basic_setup();
+	debugger_entry();
 
 	prepare_namespace();
 
--- linux-2.6.3-rc4/kernel/Kconfig.kgdb	1969-12-31 17:00:00.000000000 -0700
+++ linux-2.6.3-rc4-kgdb/kernel/Kconfig.kgdb	2004-02-17 11:34:00.111514958 -0700
@@ -0,0 +1,141 @@
+config KGDB
+	bool "KGDB: kernel debugging with remote gdb"
+	depends on DEBUG_KERNEL
+	select DEBUG_INFO
+	select FRAME_POINTER
+	# XXX: Doesn't work w/o this right now
+	select KGDB_THREAD if PPC32
+	help
+	  If you say Y here, it will be possible to remotely debug the
+	  kernel using gdb. This enlarges your kernel image disk size by
+	  several megabytes and requires a machine with more than 128 MB
+	  RAM to avoid excessive linking time. 
+	  Documentation of kernel debugger available at
+	  http://kgdb.sourceforge.net
+	  This is only useful for kernel hackers. If unsure, say N.
+
+choice
+	prompt "Method for KGDB communication"
+	depends on KGDB
+	default PPC_SIMPLE_SERIAL if PPC32 && (8xx || 8260)
+	default KGDB_8250
+	help
+	  There are a number of different ways in which you can communicate
+	  with KGDB.  The oldest is using a serial driver.  A newer method
+	  is to use UDP packets and a special network driver.
+
+config KGDB_8250
+	bool "KGDB: On generic serial port (8250)"
+	help
+	  Uses generic serial port (8250) for kgdb. This is independent of the
+	  option 9250/16550 and compatible serial port.
+
+config KGDB_ETH
+	bool "KGDB: On ethernet"
+	select NETPOLL
+	select NETPOLL_TRAP
+	select NETPOLL_RX
+	help
+	  Uses ethernet interface for kgdb.
+
+config PPC_SIMPLE_SERIAL 
+	bool "KGDB: On any serial port"
+	depends on PPC32
+	help
+	  Use a very simple, and not necessarily feature complete serial
+	  driver.  This is the only serial option currently for MPC8xx or
+	  MPC82xx based ports that do not offer an 8250-style UART.
+
+endchoice
+
+config KGDB_SIMPLE_SERIAL
+	bool "Simple selection of KGDB serial port"
+	depends on KGDB_8250 || PPC_SIMPLE_SERIAL
+	help
+	  If you say Y here, you will only have to pick the baud rate
+	  and serial port (ttyS) that you wish to use for KGDB.  If you
+	  say N, you will have provide the I/O port and IRQ number.  Note
+	  that if your serial ports are iomapped, then you must say Y here.
+	  If in doubt, say Y.
+
+choice
+	depends on KGDB_8250 || PPC_SIMPLE_SERIAL
+    	prompt "Debug serial port BAUD"
+	default KGDB_115200BAUD
+	help
+	  Gdb and the kernel stub need to agree on the baud rate to be
+	  used.  Some systems (x86 family at this writing) allow this to
+	  be configured.
+
+config KGDB_9600BAUD
+	bool "9600"
+
+config KGDB_19200BAUD
+	bool "19200"
+
+config KGDB_38400BAUD
+	bool "38400"
+
+config KGDB_57600BAUD
+	bool "57600"
+
+config KGDB_115200BAUD
+	bool "115200"
+endchoice
+
+choice
+	prompt "Serial port for KGDB"
+	depends on KGDB_SIMPLE_SERIAL
+	default KGDB_TTYS0
+
+config KGDB_TTYS0
+	bool "ttyS0"
+
+config KGDB_TTYS1
+	bool "ttyS1"
+
+config KGDB_TTYS2
+	bool "ttyS2"
+
+config KGDB_TTYS3
+	bool "ttyS3"
+
+endchoice
+
+config KGDB_PORT
+	hex "hex I/O port address of the debug serial port"
+	depends on !KGDB_SIMPLE_SERIAL && (KGDB_8250 || PPC_SIMPLE_SERIAL)
+	default  3f8
+	help
+	  Some systems (x86 family at this writing) allow the port
+	  address to be configured.  The number entered is assumed to be
+	  hex, don't put 0x in front of it.  The standard address are:
+	  COM1 3f8 , irq 4 and COM2 2f8 irq 3.  Setserial /dev/ttySx
+	  will tell you what you have.  It is good to test the serial
+	  connection with a live system before trying to debug.
+
+config KGDB_IRQ
+	int "IRQ of the debug serial port"
+	depends on !KGDB_SIMPLE_SERIAL && (KGDB_8250 || PPC_SIMPLE_SERIAL)
+	default 4
+	help
+	  This is the irq for the debug port.  If everything is working
+	  correctly and the kernel has interrupts on a control C to the
+	  port should cause a break into the kernel debug stub.
+
+config KGDB_THREAD
+	bool "KGDB: Thread analysis"
+	depends on KGDB
+	help
+	  With thread analysis enabled, gdb can talk to kgdb stub to list
+	  threads and to get stack trace for a thread. This option also enables
+	  some code which helps gdb get exact status of thread. Thread analysis
+	  adds some overhead to schedule and down functions. You can disable
+	  this option if you do not want to compromise on speed.
+
+config KGDB_CONSOLE
+	bool "KGDB: Console messages through gdb"
+	depends on KGDB
+	help
+	  If you say Y here, console messages will appear through gdb.
+	  Other consoles such as tty or ttyS will continue to work as usual.
--- linux-2.6.3-rc4/kernel/Makefile	2004-02-17 09:51:25.000000000 -0700
+++ linux-2.6.3-rc4-kgdb/kernel/Makefile	2004-02-17 11:33:52.879156407 -0700
@@ -19,6 +19,7 @@ obj-$(CONFIG_BSD_PROCESS_ACCT) += acct.o
 obj-$(CONFIG_COMPAT) += compat.o
 obj-$(CONFIG_IKCONFIG) += configs.o
 obj-$(CONFIG_IKCONFIG_PROC) += configs.o
+obj-$(CONFIG_KGDB) += kgdbstub.o
 
 ifneq ($(CONFIG_IA64),y)
 # According to Alan Modra <alan@linuxcare.com.au>, the -fno-omit-frame-pointer is
--- linux-2.6.3-rc4/kernel/kgdbstub.c	1969-12-31 17:00:00.000000000 -0700
+++ linux-2.6.3-rc4-kgdb/kernel/kgdbstub.c	2004-02-17 11:34:00.171501343 -0700
@@ -0,0 +1,1300 @@
+/*
+ * 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) 2000-2001 VERITAS Software Corporation.
+ * Copyright (C) 2002-2004 Timesys Corporation
+ * Copyright (C) 2003-2004 Amit S. Kale
+ * Copyright (C) 2004 Pavel Machek <pavel@suse.cz>
+ *
+ * Restructured KGDB for 2.6 kernels.
+ * thread support, support for multiple processors,support for ia-32(x86) 
+ * hardware debugging, Console support, handling nmi watchdog
+ * - Amit S. Kale ( amitkale@emsyssoft.com )
+ *
+ * Several enhancements by George Anzinger <george@mvista.com>
+ * Generic KGDB Support
+ * Implemented by Anurekh Saxena (anurekh.saxena@timesys.com)
+ * 
+ * Contributor:     Lake Stevens Instrument Division
+ * Written by:      Glenn Engel
+ *  
+ * Modified for 386 by Jim Kingdon, Cygnus Support.
+ * Origianl kgdb, compatibility with 2.1.xx kernel by David Grothe <dave@gcom.com>
+ * Integrated into 2.2.5 kernel by Tigran Aivazian <tigran@sco.com>
+ */
+
+#include <linux/string.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/smp.h>
+#include <linux/spinlock.h>
+#include <linux/delay.h>
+#include <linux/mm.h>
+#include <asm/system.h>
+#include <asm/ptrace.h>		/* for linux pt_regs struct */
+#include <asm/uaccess.h>
+#include <linux/kgdb.h>
+#include <asm/atomic.h>
+#include <linux/notifier.h>
+#include <linux/module.h>
+#include <asm/cacheflush.h>
+#include <linux/netpoll.h>
+
+#ifdef CONFIG_KGDB_CONSOLE
+#include <linux/console.h>
+#endif
+ 
+#include <linux/init.h>
+
+/*
+ * The following are the stub functions for code which is arch specific
+ * and can be omitted on some arches
+ */
+
+/*
+ * This function will handle the initalization of any architecture specific
+ * hooks.
+ */
+int __attribute__ ((weak))
+kgdb_arch_init(void)
+{
+	return 0;
+}
+
+void __attribute__ ((weak))
+regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
+{
+}
+
+void __attribute__ ((weak))
+sleeping_thread_to_gdb_regs(unsigned long *gdb_regs,struct task_struct *p)
+{
+}
+
+void __attribute__ ((weak))
+gdb_regs_to_regs(unsigned long *gdb_regs, struct pt_regs *regs)
+{
+}
+
+void __attribute__ ((weak))
+kgdb_printexceptioninfo(int exceptionNo, int errorcode, char *buffer)
+{
+}
+
+void __attribute__ ((weak))
+kgdb_disable_hw_debug(struct pt_regs *regs)
+{
+}
+
+void __attribute__ ((weak))
+kgdb_post_master_code(struct pt_regs *regs, int eVector, int err_code)
+{
+}
+
+/*
+ * Handle any additional commands.  This must handle the 'c' and 's'
+ * command packets.
+ * Return -1 to loop over other commands, and 0 to exit from KGDB
+ */
+int __attribute__ ((weak))
+kgdb_arch_handle_exception(int vector, int signo, int err_code, char *InBuffer,
+		char *outBuffer, struct pt_regs *regs)
+{
+	return -1;	/* Do not exit from the handler. */
+}
+
+int __attribute__ ((weak))
+kgdb_arch_set_break(unsigned long addr, int type)
+{
+	return 0;
+}
+
+int __attribute__ ((weak))
+kgdb_arch_remove_break(unsigned long addr, int type)
+{
+	return 0;
+}
+
+void __attribute__ ((weak))
+kgdb_correct_hw_break(void)
+{
+}
+
+void __attribute__ ((weak))
+kgdb_shadowinfo(struct pt_regs *regs, char *buffer, unsigned threadid)
+{
+}
+
+struct task_struct __attribute__ ((weak))
+*kgdb_get_shadow_thread(struct pt_regs *regs, int threadid)
+{
+	return NULL;
+}
+
+struct pt_regs __attribute__ ((weak))
+*kgdb_shadow_regs(struct pt_regs *regs, int threadid)
+{
+	return NULL;
+}
+
+/*
+ * The following is a stub IO driver.  Not all IO drivers will find it
+ * necessary to provide all of these functions.
+ */
+/* Get the next character in the packet. */
+int __attribute__ ((weak))
+kgdb_get_debug_char(void)
+{
+	return 0;
+}
+
+/* Write, or at least buffer, a single debug character. */
+void __attribute__ ((weak))
+kgdb_put_debug_char(int ch)
+{
+	return;
+}
+
+/* Make sure any pending characters are out there. */
+void __attribute__ ((weak))
+kgdb_flush_io(void)
+{
+	return;
+}
+
+/* Do any setup that is required to run. */
+int __attribute__ ((weak))
+kgdb_hook_io(void)
+{
+	return 0;
+}
+
+struct kgdb_arch *kgdb_ops = &arch_kgdb_ops;
+gdb_breakpoint_t kgdb_break[MAX_BREAKPOINTS];
+extern int pid_max;
+
+int kgdb_initialized = 0;
+int kgdb_enter = 0;
+static const char hexchars[] = "0123456789abcdef";
+
+static int get_char(char *addr, unsigned char *data, int can_fault);
+static int set_char(char *addr, int data, int can_fault);
+
+spinlock_t slavecpulocks[KGDB_MAX_NO_CPUS];
+static volatile int procindebug[KGDB_MAX_NO_CPUS];
+atomic_t kgdb_setting_breakpoint;
+volatile int kgdb_connected;
+struct task_struct *kgdb_usethread, *kgdb_contthread;
+
+int debugger_step;
+atomic_t debugger_active;
+
+/* 
+ * Indicate to caller of kgdb_mem2hex or hex2mem that there has been an
+ * error.  
+ */
+volatile int kgdb_memerr = 0;
+volatile int debugger_memerr_expected = 0;
+
+/* This will point to kgdb_handle_exception by default.
+ * The architecture code can override this in its init function
+ */
+gdb_debug_hook *linux_debug_hook;
+
+
+static char remcomInBuffer[BUFMAX];
+static char remcomOutBuffer[BUFMAX];
+static short error;
+
+static int module_event(struct notifier_block * self, unsigned long val,
+		void * data);
+
+static struct notifier_block kgdb_module_load_nb = {
+	.notifier_call = module_event,
+};
+
+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 $<data>#<checksum>	*/
+static void
+getpacket(char *buffer)
+{
+	unsigned char checksum;
+	unsigned char xmitcsum;
+	int count;
+	char ch;
+
+	do {
+	/* wait around for the start character, ignore all other characters */
+		while ((ch = (kgdb_get_debug_char() & 0x7f)) != '$')
+			;	/* Spin */
+		kgdb_connected = 1;
+		checksum = 0;
+		xmitcsum = -1;
+
+		count = 0;
+
+		/* now, read until a # or end of buffer is found */
+		while (count < BUFMAX) {
+			ch = kgdb_get_debug_char() & 0x7f;
+			if (ch == '#')
+				break;
+			checksum = checksum + ch;
+			buffer[count] = ch;
+			count = count + 1;
+		}
+		buffer[count] = 0;
+
+		if (ch == '#') {
+			xmitcsum = hex(kgdb_get_debug_char() & 0x7f) << 4;
+			xmitcsum += hex(kgdb_get_debug_char() & 0x7f);
+
+			if (checksum != xmitcsum)
+				/* Retransmit. */
+				kgdb_put_debug_char('-');
+			else
+				/* ACK. */
+				kgdb_put_debug_char('+');
+
+			kgdb_flush_io();
+		}
+	} while (checksum != xmitcsum);
+}
+
+
+/*
+ * Send the packet in buffer.
+ * Check for gdb connection if asked for.
+ */
+static void
+putpacket(char *buffer)
+{
+	unsigned char checksum;
+	int count;
+	char ch;
+
+	/*  $<packet info>#<checksum>. */
+	do {
+		checksum = 0;
+		count = 0;
+
+		/* Write out the packet. */
+		kgdb_put_debug_char('$');
+		while ((ch = buffer[count])) {
+			kgdb_put_debug_char(ch);
+			checksum += ch;
+			count++;
+		}
+
+		kgdb_put_debug_char('#');
+		kgdb_put_debug_char(hexchars[checksum >> 4]);
+		kgdb_put_debug_char(hexchars[checksum % 16]);
+		kgdb_flush_io();
+	} while ((kgdb_get_debug_char() & 0x7f) != '+');
+}
+
+/*
+ * convert the memory pointed to by mem into hex, placing result in buf
+ * return a pointer to the last char put in buf (null)
+ * If MAY_FAULT is non-zero, then we should set kgdb_memerr in response to
+ * a fault; if zero treat a fault like any other fault in the stub.
+ */
+char *kgdb_mem2hex(char *mem, char *buf, int count, int can_fault)
+{
+	int i;
+	unsigned char ch;
+	
+	for (i = 0; i < count; i++) {
+
+		if (get_char(mem++, &ch, can_fault) < 0) 
+			break;
+		
+		*buf++ = hexchars[ch >> 4];
+		*buf++ = hexchars[ch % 16];
+	}
+	*buf = 0;
+	return (buf);
+}
+
+/* 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 */
+
+char *hex2mem(char *buf, char *mem, int count, int can_fault)
+{
+	int i;
+	unsigned char ch;
+	
+	for (i = 0; i < count; i++) {
+		ch = hex(*buf++) << 4;
+		ch = ch + hex(*buf++);
+		if (set_char(mem++, ch, can_fault) < 0) 
+			break;
+	}
+	return (mem);
+}
+
+/*
+ * While we find nice hex chars, build a longValue.
+ * Return number of chars processed.
+ */
+int kgdb_hex2long(char **ptr, long *longValue)
+{
+	int numChars = 0;
+	int hexValue;
+
+	*longValue = 0;
+
+	while (**ptr) {
+		hexValue = hex(**ptr);
+		if (hexValue >= 0) {
+			*longValue = (*longValue << 4) | hexValue;
+			numChars++;
+		} else
+			break;
+
+		(*ptr)++;
+	}
+
+	return (numChars);
+}
+
+static inline char *pack_hex_byte(char *pkt, int byte)
+{
+	*pkt++ = hexchars[(byte >> 4) & 0xf];
+	*pkt++ = hexchars[(byte & 0xf)];
+	return pkt;
+}
+
+#define BUF_THREAD_ID_SIZE 16
+
+static char *pack_threadid(char *pkt, threadref *id)
+{
+	char *limit;
+	unsigned char *altid;
+
+	altid = (unsigned char *) id;
+	limit = pkt + BUF_THREAD_ID_SIZE;
+	while (pkt < limit)
+		pkt = pack_hex_byte(pkt, *altid++);
+
+	return pkt;
+}
+
+void int_to_threadref(threadref *id, int value)
+{
+	unsigned char *scan;
+
+	scan = (unsigned char *) id;
+	{
+		int i = 4;
+		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)
+{
+	int i;
+	struct list_head *l;
+	struct task_struct *p;
+	struct pid *pid;
+
+	if (tid >= pid_max + num_online_cpus() + kgdb_ops->shadowth) {
+		return NULL;
+	}
+	if (tid >= pid_max + num_online_cpus()) {
+		return kgdb_get_shadow_thread(regs, tid - pid_max -
+				num_online_cpus());
+	}
+	if (tid >= pid_max) {
+		i = 0;
+		for_each_task_pid(0, PIDTYPE_PID, p, l, pid) {
+			if (tid == pid_max + i) {
+				return p;
+			}
+			i++;
+		}
+		return NULL;
+	}
+	if (!tid) {
+		return NULL;
+	}
+	return find_task_by_pid(tid);
+}
+
+#ifdef CONFIG_SMP
+void kgdb_wait(struct pt_regs *regs)
+{
+	unsigned long flags;
+	int processor;
+
+	local_irq_save(flags);
+	processor = smp_processor_id();
+	procindebug[processor] = 1;
+	current->thread.debuggerinfo = regs;
+
+	/* Wait till master processor goes completely into the debugger. FIXME: this looks racy */
+	while (!procindebug[atomic_read(&debugger_active) - 1]) {
+		int i = 10;	/* an arbitrary number */
+
+		while (--i)
+			asm volatile ("nop": : : "memory");
+		barrier();
+	}
+
+	/* Wait till master processor is done with debugging */
+	spin_lock(slavecpulocks + processor);
+
+	/* This has been taken from x86 kgdb implementation and
+	 * will be needed by architectures that have SMP support
+	 */
+	kgdb_correct_hw_break();
+
+	/* Signal the master processor that we are done */
+	procindebug[processor] = 0;
+	spin_unlock(slavecpulocks + processor);
+	local_irq_restore(flags);
+}
+#endif
+
+static void get_mem (char *addr, unsigned char *buf, int count)
+{
+	while (count) {
+		if(get_char(addr++, buf, 1) <  0) 
+			return;
+		buf++;
+		count--;
+	}
+}
+
+static void set_mem (char *addr,unsigned char *buf, int count)
+{
+	while (count) {
+		if (set_char(addr++,*buf++, 1) < 0) 
+			return;
+		count--;
+	}
+}
+
+static int set_break (unsigned long addr)
+{
+	int i, breakno = -1;
+
+	for (i = 0; i < MAX_BREAKPOINTS; i++) {
+		if ((kgdb_break[i].state == bp_enabled) &&
+		    (kgdb_break[i].bpt_addr == addr)) {
+			breakno = -1;
+			break;
+		}
+
+		if (kgdb_break[i].state == bp_disabled) {
+			if ((breakno == -1) || (kgdb_break[i].bpt_addr == addr))
+				breakno = i;
+		}
+	}
+	if (breakno == -1)
+		return -1;
+
+	get_mem((char *)addr, kgdb_break[breakno].saved_instr, BREAK_INSTR_SIZE);
+	if (kgdb_memerr)
+		return -1;
+
+	set_mem((char *)addr, kgdb_ops->gdb_bpt_instr, BREAK_INSTR_SIZE);
+	flush_cache_range (current->mm, addr, addr + BREAK_INSTR_SIZE);
+	flush_icache_range (addr, addr + BREAK_INSTR_SIZE);
+	if (kgdb_memerr)
+		return -1;
+
+	kgdb_break[breakno].state = bp_enabled;
+	kgdb_break[breakno].type = bp_breakpoint;
+	kgdb_break[breakno].bpt_addr = addr;
+	
+	return 0;
+}	
+
+static int remove_break (unsigned long addr)
+{
+	int i;
+
+	for (i=0; i < MAX_BREAKPOINTS; i++) {
+		if ((kgdb_break[i].state == bp_enabled) &&
+		   (kgdb_break[i].bpt_addr == addr)) {
+			set_mem((char *)addr, kgdb_break[i].saved_instr,
+			        BREAK_INSTR_SIZE);
+			flush_cache_range (current->mm, addr, addr + BREAK_INSTR_SIZE);
+			flush_icache_range (addr, addr + BREAK_INSTR_SIZE);
+			if (kgdb_memerr)
+				return -1;
+			kgdb_break[i].state = bp_disabled;
+			return 0;
+		}
+	}
+	return -1;
+}
+
+int remove_all_break(void)
+{
+	int i;
+	for (i=0; i < MAX_BREAKPOINTS; i++) {
+		if(kgdb_break[i].state == bp_enabled) {
+			unsigned long addr = kgdb_break[i].bpt_addr;
+			set_mem((char *)addr, kgdb_break[i].saved_instr,
+			       BREAK_INSTR_SIZE);
+			flush_cache_range (current->mm, addr, addr + BREAK_INSTR_SIZE);
+			flush_icache_range (addr, addr + BREAK_INSTR_SIZE);
+		}
+		kgdb_break[i].state = bp_disabled;
+	}
+	return 0;
+}
+		
+int get_char(char *addr, unsigned char *data, int can_fault)
+{
+	mm_segment_t fs;
+	int ret = 0;
+	
+	kgdb_memerr = 0;
+	
+	if (can_fault)
+		debugger_memerr_expected = 1;
+	wmb();
+	fs = get_fs();
+	set_fs(KERNEL_DS);
+	
+	if (get_user(*data, addr) != 0) {
+		ret = -EFAULT;
+		kgdb_memerr = 1;
+	}
+	
+	debugger_memerr_expected = 0;	
+	set_fs(fs);
+	return ret;
+}
+
+int set_char(char *addr, int data, int can_fault)
+{
+	mm_segment_t fs;
+	int ret = 0;
+	
+	kgdb_memerr = 0;
+	
+	if (can_fault)
+		debugger_memerr_expected = 1;
+	wmb();
+	fs = get_fs();
+	set_fs(KERNEL_DS);
+
+	if (put_user(data, addr) != 0) {
+		ret = -EFAULT;
+		kgdb_memerr = 1;
+	}
+	
+	debugger_memerr_expected = 0;
+	set_fs(fs);
+	return ret;
+}
+
+static inline int shadow_pid(int realpid)
+{
+	if (realpid) {
+		return realpid;
+	}
+	return pid_max + smp_processor_id();
+}
+
+/*
+ * This function does all command procesing for interfacing to gdb.
+ *
+ * Locking hierarchy:
+ *	interface locks, if any (begin_session)
+ *	kgdb lock (debugger_active)
+ *
+ */
+int kgdb_handle_exception(int exVector, int signo, int err_code, 
+                     struct pt_regs *linux_regs)
+{
+	unsigned long length, addr;
+	char *ptr;
+	unsigned long flags;
+	unsigned long gdb_regs[NUMREGBYTES / sizeof (unsigned long)];
+	int i;
+	long threadid;
+	threadref thref;
+	struct task_struct *thread = NULL;
+	unsigned procid;
+	int ret = 0;
+	static char tmpstr[256];
+	int numshadowth = num_online_cpus() + kgdb_ops->shadowth;
+	long kgdb_usethreadid = 0;
+
+	/* Panic on recursive debugger calls. */
+	if (atomic_read(&debugger_active) == smp_processor_id() + 1) {
+		return 0;
+	}
+
+	/* 
+	 * Interrupts will be restored by the 'trap return' code, except when
+	 * single stepping.
+	 */
+	local_irq_save(flags);
+	
+	/* Hold debugger_active */
+	procid = smp_processor_id();
+	while (cmpxchg(&atomic_read(&debugger_active), 0, (procid + 1)) != 0) {
+		int i = 25;	/* an arbitrary number */
+
+		while (--i)
+			asm volatile ("nop": : : "memory");
+	}
+	
+	debugger_step = 0;
+
+	current->thread.debuggerinfo = linux_regs;
+
+	kgdb_disable_hw_debug(linux_regs);
+
+	for (i = 0; i < num_online_cpus(); i++) {
+		spin_lock(&slavecpulocks[i]);
+	}
+
+	/* spin_lock code is good enough as a barrier so we don't
+	 * need one here */
+	procindebug[smp_processor_id()] = 1;
+
+	/* Clear the out buffer. */
+	memset(remcomOutBuffer, 0, sizeof(remcomOutBuffer));
+
+	/* Master processor is completely in the debugger */
+	kgdb_post_master_code(linux_regs, exVector, err_code);
+
+	/* If kgdb is connected, then an exception has occured, and
+	 * we need to pass something back to GDB. */
+	if (kgdb_connected) {
+		ptr = remcomOutBuffer;
+		*ptr++ = 'T';
+		*ptr++ = hexchars[(signo >> 4) % 16];
+		*ptr++ = hexchars[signo % 16];
+		*ptr++ = hexchars[(PC_REGNUM >> 4) % 16];
+		*ptr++ = hexchars[PC_REGNUM % 16];
+		*ptr++ = ':';
+		ptr = kgdb_mem2hex((char *)&linux_regs->PTRACE_PC, ptr, 4, 0);
+		*ptr++ = ';';
+		*ptr++ = hexchars[SP_REGNUM >> 4];
+		*ptr++ = hexchars[SP_REGNUM & 0xf];
+		*ptr++ = ':';
+		ptr = kgdb_mem2hex(((char *)linux_regs) + SP_REGNUM * 4, ptr,
+				4, 0);
+		*ptr++ = ';';
+		ptr += strlen(strcpy(ptr, "thread:"));
+		int_to_threadref(&thref, shadow_pid(current->pid));
+		ptr = pack_threadid(ptr, &thref);
+		*ptr++ = ';';
+
+		putpacket(remcomOutBuffer);
+	}
+
+	kgdb_usethread = current;
+	kgdb_usethreadid = shadow_pid(current->pid);
+
+	while (1) {
+		int bpt_type = 0;
+		error = 0;
+
+		/* Clear the out buffer. */
+		memset(remcomOutBuffer, 0, sizeof(remcomOutBuffer));
+
+		getpacket(remcomInBuffer);
+
+#if KGDB_DEBUG
+		bust_spinlocks(1);
+		printk("CPU%d pid%d GDB packet: %s\n", 
+		       smp_processor_id(), current->pid, remcomInBuffer);
+		bust_spinlocks(0);
+#endif
+		switch (remcomInBuffer[0]) {
+		case '?':
+			/* reply to host that an exception has occurred */
+			ptr = remcomOutBuffer;
+			*ptr++ = 'T';
+			*ptr++ = hexchars[(signo >> 4) % 16];
+			*ptr++ = hexchars[signo % 16];
+			*ptr++ = hexchars[(PC_REGNUM >> 4) % 16];
+			*ptr++ = hexchars[PC_REGNUM % 16];
+			*ptr++ = ':';
+			ptr = kgdb_mem2hex((char *)&linux_regs->PTRACE_PC, ptr,
+					4, 0);
+			*ptr++ = ';';
+			*ptr++ = hexchars[SP_REGNUM >> 4];
+			*ptr++ = hexchars[SP_REGNUM & 0xf];
+			*ptr++ = ':';
+			ptr = kgdb_mem2hex(((char *)linux_regs) + SP_REGNUM * 4,
+					ptr, 4, 0);
+			*ptr++ = ';';
+			ptr += strlen(strcpy(ptr, "thread:"));
+			int_to_threadref(&thref, shadow_pid(current->pid));
+			ptr = pack_threadid(ptr, &thref);
+			*ptr++ = ';';
+			break;
+		case 'g':	/* return the value of the CPU registers */
+			thread = kgdb_usethread;
+				
+			if (!thread)
+				thread = current;
+			
+			/* 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 (kgdb_usethreadid >= pid_max + num_online_cpus()) {
+				regs_to_gdb_regs(gdb_regs,
+					kgdb_shadow_regs(linux_regs,
+						kgdb_usethreadid - pid_max -
+						num_online_cpus()));
+			} else if (thread->thread.debuggerinfo) {
+				if (get_char(thread->thread.debuggerinfo,
+					(unsigned char *)gdb_regs, 1)) {
+					strcpy(remcomOutBuffer, "E10");
+					break;
+				}
+				regs_to_gdb_regs(gdb_regs,
+					(struct pt_regs *)
+					thread->thread.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, remcomOutBuffer, NUMREGBYTES, 0);
+			break;
+
+		case 'G':	/* set the value of the CPU registers - return OK */
+			hex2mem(&remcomInBuffer[1], (char *) gdb_regs,
+				NUMREGBYTES, 0);
+				
+			if (kgdb_usethread && kgdb_usethread != current)
+				strcpy(remcomOutBuffer, "E00");
+			else {
+				gdb_regs_to_regs(gdb_regs,
+					(struct pt_regs *)
+					current->thread.debuggerinfo);
+				strcpy(remcomOutBuffer, "OK");
+			}
+
+			break;
+
+			/* mAA..AA,LLLL  Read LLLL bytes at address AA..AA */
+		case 'm':
+			/* TRY TO READ %x,%x.  IF SUCCEED, SET PTR = 0 */
+			ptr = &remcomInBuffer[1];
+			if (kgdb_hex2long(&ptr, &addr) && *ptr++ == ',' &&
+			    kgdb_hex2long(&ptr, &length)) {
+				ptr = 0;
+				kgdb_mem2hex((char *) addr, remcomOutBuffer, length, 1);
+				if (kgdb_memerr)
+					strcpy(remcomOutBuffer, "E03");
+					
+			}
+
+			if (ptr) 
+				strcpy(remcomOutBuffer, "E01");
+			break;
+
+		/* MAA..AA,LLLL: Write LLLL bytes at address AA.AA return OK */
+		case 'M':
+			/* TRY TO READ '%x,%x:'.  IF SUCCEED, SET PTR = 0 */
+			ptr = &remcomInBuffer[1];
+			if (kgdb_hex2long(&ptr, &addr) && *(ptr++) == ',' && 
+			    kgdb_hex2long(&ptr, &length) && *(ptr++) == ':') {
+				hex2mem(ptr, (char *)addr, length, 1);
+				if (kgdb_memerr)
+					strcpy(remcomOutBuffer, "E09");
+				else
+					strcpy(remcomOutBuffer, "OK");
+				ptr = 0;
+			}
+			if (ptr) {
+				strcpy(remcomOutBuffer, "E02");
+			}
+			break;
+		/* GDB has told us it is detaching.  So we'll remove all of
+		 * our breakpoints and get back to 'normal'. */
+		case 'D':
+			strcpy(remcomOutBuffer, "OK");
+			putpacket(remcomOutBuffer);
+			/* fall through. */
+		/* GDB is telling us to 'kill' the running process.  We'll
+		 * just stop debugging. */
+		case 'k':
+			remove_all_break();
+			kgdb_connected = 0;
+			goto kgdb_exit;
+		/* query */
+		case 'q':
+			switch (remcomInBuffer[1]) {
+			case 's':
+			case 'f':
+				if (memcmp(remcomInBuffer+2, "ThreadInfo",10))
+				{
+					strcpy(remcomOutBuffer, "E04");
+					break;
+				}
+				if (remcomInBuffer[1] == 'f') {
+					threadid = 1;
+				}
+				remcomOutBuffer[0] = 'm';
+				ptr = remcomOutBuffer + 1;
+				for (i = 0; i < 32 && threadid < pid_max + numshadowth;
+						threadid++) {
+					thread = getthread(linux_regs, threadid);
+					if (thread) {
+						int_to_threadref(&thref,
+								threadid);
+						pack_threadid(ptr, &thref);
+						ptr += 16;
+						*(ptr++) = ',';
+						i++;
+					}
+				}
+				break;
+
+			case 'C':
+				/* Current thread id */
+				strcpy(remcomOutBuffer, "QC");
+
+				threadid = shadow_pid(current->pid);
+				
+				int_to_threadref(&thref, threadid);
+				pack_threadid(remcomOutBuffer + 2, &thref);
+				break;
+
+			case 'E':
+				/* Print exception info */
+				kgdb_printexceptioninfo(exVector, err_code,
+						remcomOutBuffer);
+				break;
+			case 'T':
+				if (memcmp(remcomInBuffer+1, "ThreadExtraInfo,",16))
+				{
+					strcpy(remcomOutBuffer, "E05");
+					break;
+				}
+				threadid = 0;
+				ptr = remcomInBuffer+17;
+				kgdb_hex2long(&ptr, &threadid);
+				if (!getthread(linux_regs, threadid)) {
+					sprintf(tmpstr, "invalid pid %d",
+							(int) threadid);
+					kgdb_mem2hex(tmpstr, remcomOutBuffer,
+							strlen(tmpstr), 0);
+					break;
+				}
+				if (threadid < pid_max) {
+					kgdb_mem2hex(getthread(linux_regs, threadid)->comm,
+							remcomOutBuffer, 16, 0);
+				} else if (threadid >= pid_max +
+						num_online_cpus()) {
+					kgdb_shadowinfo(linux_regs,
+						remcomOutBuffer,
+						threadid - pid_max -
+						num_online_cpus());
+				} else {
+					sprintf(tmpstr, "Shadow task %d for pid 0",
+							(int)(threadid -
+							      pid_max));
+					kgdb_mem2hex(tmpstr, remcomOutBuffer,
+							strlen(tmpstr), 0);
+				}
+				break;
+			}
+			break;
+
+			/* task related */
+		case 'H':
+			switch (remcomInBuffer[1]) {
+			case 'g':
+				ptr = &remcomInBuffer[2];
+				kgdb_hex2long(&ptr, &threadid);
+				thread = getthread(linux_regs, threadid);
+				if (!thread && threadid > 0) {
+					remcomOutBuffer[0] = 'E';
+					break;
+				}
+				kgdb_usethread = thread;
+				kgdb_usethreadid = threadid;
+				strcpy(remcomOutBuffer, "OK");
+				break;
+
+			case 'c':
+				ptr = &remcomInBuffer[2];
+				kgdb_hex2long(&ptr, &threadid);
+				if (!threadid) {
+					kgdb_contthread = 0;
+				} else {
+					thread = getthread(linux_regs, threadid);
+					if (!thread && threadid > 0) {
+						remcomOutBuffer[0] = 'E';
+						break;
+					}
+					kgdb_contthread = thread;
+				}
+				strcpy(remcomOutBuffer, "OK");
+				break;
+			}
+			break;
+
+			/* Query thread status */
+		case 'T':
+			ptr = &remcomInBuffer[1];
+			kgdb_hex2long(&ptr, &threadid);
+			thread = getthread(linux_regs, threadid);
+			if (thread)
+				strcpy(remcomOutBuffer, "OK");
+			else
+				remcomOutBuffer[0] = 'E';
+			break;
+		case 'z':
+		case 'Z':
+			ptr = &remcomInBuffer[2];
+			if (*(ptr++) != ',') {
+				strcpy(remcomOutBuffer, "E07");
+				break;
+			}
+			kgdb_hex2long(&ptr, &addr);
+			
+			bpt_type = remcomInBuffer[1];
+			if (bpt_type != bp_breakpoint) {
+				if (bpt_type == bp_hardware_breakpoint && 
+				    !(kgdb_ops->flags & KGDB_HW_BREAKPOINT))
+					break;
+
+				/* if set_break is not defined, then
+				 * remove_break does not matter
+				 */
+				if(!(kgdb_ops->flags & KGDB_HW_BREAKPOINT))
+					break;
+			}
+			
+			if (remcomInBuffer[0] == 'Z') {
+				if (bpt_type == bp_breakpoint)
+					ret = set_break(addr);
+				else
+					ret = kgdb_arch_set_break(addr,
+							bpt_type);
+			}
+			else {
+				if (bpt_type == bp_breakpoint)
+					ret = remove_break(addr);
+				else
+					ret = kgdb_arch_remove_break(addr,
+							bpt_type);
+			}
+			
+			if (ret == 0)
+				strcpy(remcomOutBuffer, "OK");
+			else
+				strcpy(remcomOutBuffer, "E08");
+			
+			break;
+
+		default:
+			if (kgdb_arch_handle_exception(exVector, signo,
+						err_code, remcomInBuffer,
+						remcomOutBuffer,
+						linux_regs) >= 0)
+				/* Get out of here. */
+				goto kgdb_exit;
+		}		/* switch */
+#if KGDB_DEBUG
+		bust_spinlocks(1);
+		printk("Response to GDB: %s\n", remcomOutBuffer);
+		bust_spinlocks(0);
+#endif
+
+		/* reply to the request */
+		putpacket(remcomOutBuffer);
+	}
+
+kgdb_exit:
+	procindebug[smp_processor_id()] = 0;	
+	
+	for (i = 0; i < num_online_cpus(); i++) {
+		spin_unlock(&slavecpulocks[i]);
+	}
+	/* Wait till all the processors have quit
+	 * from the debugger 
+	 */
+	for (i = 0; i < num_online_cpus(); i++) { 
+		while (procindebug[i]) {
+			int j = 10; /* an arbitrary number */
+
+			while (--j) {
+				asm volatile ("nop" : : : "memory");
+			}
+			barrier();
+		}
+	}
+
+	/* Free debugger_active */
+	atomic_set(&debugger_active, 0);
+	local_irq_restore(flags);
+
+	return ret;
+}
+
+/*
+ * GDB places a breakpoint at this function to know dynamically
+ * loaded objects. It's not defined static so that only one instance with this
+ * name exists in the kernel.
+ */
+
+int module_event(struct notifier_block * self, unsigned long val, void * data)
+{
+	return 0;
+}
+
+/* this function is used to set up exception handlers for tracing and
+   breakpoints */
+static void set_debug_traps(void)
+{
+	int i;
+	
+	for (i = 0; i < KGDB_MAX_NO_CPUS; i++) 
+		spin_lock_init(&slavecpulocks[i]);
+
+	/* Free debugger_active */
+	atomic_set(&debugger_active, 0);
+
+	for (i = 0; i < MAX_BREAKPOINTS; i++) 
+		kgdb_break[i].state = bp_disabled;
+
+	linux_debug_hook = kgdb_handle_exception;
+
+	/* We can't do much if this fails */
+	register_module_notifier(&kgdb_module_load_nb);
+
+#ifdef CONFIG_KGDB_ETH
+	/* Tell netpoll our client might need ARP */
+	netpoll_set_trap(1);
+#endif
+
+	kgdb_initialized = 1;
+
+	atomic_set(&kgdb_setting_breakpoint, 0);
+}
+
+/* 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 breakpoint(void)
+{
+	if (!kgdb_initialized)
+		set_debug_traps();
+
+	atomic_set(&kgdb_setting_breakpoint, 1);
+	wmb();
+	BREAKPOINT();
+	wmb();
+	atomic_set(&kgdb_setting_breakpoint, 0);
+}
+
+void kgdb_nmihook(int cpu, void *regs)
+{
+#ifdef CONFIG_SMP
+	if (!procindebug[cpu] && atomic_read(&debugger_active) != (cpu + 1)) {
+		kgdb_wait((struct pt_regs *)regs);
+	}
+#endif
+}
+
+void kgdb_entry(void)
+{
+	if (kgdb_initialized) {
+		/* KGDB was initialized */
+		return;
+	}
+	if (!kgdb_enter) {
+		return;
+	}
+
+	/* Let the arch do any initalization it needs to, including
+	 * pointing to a suitable early output device. */
+	kgdb_arch_init();
+
+	if (kgdb_hook_io()) {
+		/* KGDB interface isn't ready yet */
+		return;
+	}
+	
+	/*
+	 * Call GDB routine to setup the exception vectors for the debugger
+	 */
+	set_debug_traps();
+
+	/*
+	 * Call the breakpoint() routine in GDB to start the debugging
+	 * session
+	 */
+	printk(KERN_CRIT "Waiting for connection from remote gdb... ");
+	breakpoint() ;
+	printk("Connected.\n");
+}
+
+/*
+ * Sometimes we need to schedule a breakpoint because we can't break
+ * right where we are.
+ */
+static int kgdb_need_breakpoint[NR_CPUS];
+
+void kgdb_schedule_breakpoint(void)
+{
+	kgdb_need_breakpoint[smp_processor_id()] = 1;
+}
+
+void kgdb_process_breakpoint(void)
+{
+	/*
+	 * Handle a breakpoint queued from inside network driver code
+         * to avoid reentrancy issues
+	 */
+	if (kgdb_need_breakpoint[smp_processor_id()]) {
+		kgdb_need_breakpoint[smp_processor_id()] = 0;
+		breakpoint();
+	}
+}
+
+#ifdef CONFIG_KGDB_CONSOLE
+char kgdbconbuf[BUFMAX];
+
+void kgdb_console_write(struct console *co, const char *s, unsigned count)
+{
+	int i;
+	int wcount;
+	char *bufptr;
+	unsigned long flags;
+
+	if (!kgdb_connected) {
+		return;
+	}
+	local_irq_save(flags);
+
+	kgdbconbuf[0] = 'O';
+	bufptr = kgdbconbuf + 1;
+	while (count > 0) {
+		if ((count << 1) > (BUFMAX - 2)) {
+			wcount = (BUFMAX - 2) >> 1;
+		} else {
+			wcount = count;
+		}
+		count -= wcount;
+		for (i = 0; i < wcount; i++) {
+			bufptr = pack_hex_byte(bufptr, s[i]);
+		}
+		*bufptr = '\0';
+		s += wcount;
+
+		putpacket(kgdbconbuf);
+
+	}
+	local_irq_restore(flags);
+}
+
+/* Always fail so that kgdb console doesn't become the default console */
+static int __init kgdb_console_setup(struct console *co, char *options)
+{
+	return -1;
+}
+
+static struct console kgdbcons = {
+	.name = "kgdb",
+	.write = kgdb_console_write,
+	.setup = kgdb_console_setup,
+	.flags = CON_PRINTBUFFER | CON_ENABLED,
+	.index = -1,
+};
+
+static int __init kgdb_console_init(void)
+{
+	register_console(&kgdbcons);
+	return 0;
+}
+console_initcall(kgdb_console_init);
+#endif
+
+EXPORT_SYMBOL(breakpoint);
+#ifdef CONFIG_KGDB_THREAD
+EXPORT_SYMBOL(kern_schedule);
+#endif
+
+static int __init opt_kgdb_enter(char *str)
+{
+	kgdb_enter = 1;
+	return 1;
+}
+
+static int __init opt_gdb(char *str)
+{
+	kgdb_enter = 1;
+	return 1;
+}
+
+/*
+ * These options have been deprecated and are present only to maintain
+ * compatibility with kgdb for 2.4 and earlier kernels.
+ */
+#ifdef CONFIG_KGDB_8250
+extern int kgdb8250_baud;
+extern int kgdb8250_ttyS;
+static int __init opt_gdbttyS(char *str)
+{
+	kgdb8250_ttyS = simple_strtoul(str, NULL, 10);
+	return 1;
+}
+static int __init opt_gdbbaud(char *str)
+{
+	kgdb8250_baud = simple_strtoul(str, NULL, 10);
+	return 1;
+}
+#endif
+
+/*
+ *
+ * Sequence of following lines has to be maintained because gdb option is a
+ * prefix of the other two options
+ */
+
+#ifdef CONFIG_KGDB_8250
+__setup("gdbttyS=", opt_gdbttyS);
+__setup("gdbbaud=", opt_gdbbaud);
+#endif
+__setup("gdb", opt_gdb);
+__setup("kgdbwait", opt_kgdb_enter);
--- linux-2.6.3-rc4/kernel/module.c	2004-02-17 09:53:25.000000000 -0700
+++ linux-2.6.3-rc4-kgdb/kernel/module.c	2004-02-17 11:34:09.018493448 -0700
@@ -727,6 +727,11 @@ sys_delete_module(const char __user *nam
 	mod->state = MODULE_STATE_GOING;
 	restart_refcounts();
 
+	down(&notify_mutex);
+	notifier_call_chain(&module_notify_list, MODULE_STATE_GOING,
+				mod);
+	up(&notify_mutex);
+
 	/* Never wait if forced. */
 	if (!forced && module_refcount(mod) != 0)
 		wait_for_zero_refcount(mod);
@@ -1758,7 +1763,12 @@ sys_init_module(void __user *umod,
 	if (ret < 0) {
 		/* Init routine failed: abort.  Try to protect us from
                    buggy refcounters. */
+
 		mod->state = MODULE_STATE_GOING;
+		down(&notify_mutex);
+		notifier_call_chain(&module_notify_list, MODULE_STATE_GOING,
+					mod);
+		up(&notify_mutex);
 		synchronize_kernel();
 		if (mod->unsafe)
 			printk(KERN_ERR "%s: module is now stuck!\n",
--- linux-2.6.3-rc4/kernel/sched.c	2004-02-17 09:53:44.000000000 -0700
+++ linux-2.6.3-rc4-kgdb/kernel/sched.c	2004-02-17 11:34:11.756871953 -0700
@@ -37,6 +37,7 @@
 #include <linux/rcupdate.h>
 #include <linux/cpu.h>
 #include <linux/percpu.h>
+#include <linux/debugger.h>
 
 #ifdef CONFIG_NUMA
 #define cpu_to_node_mask(cpu) node_to_cpumask(cpu_to_node(cpu))
@@ -1591,7 +1592,7 @@ void scheduling_functions_start_here(voi
 /*
  * schedule() is the main scheduler function.
  */
-asmlinkage void schedule(void)
+asmlinkage void do_schedule(void)
 {
 	long *switch_count;
 	task_t *prev, *next;
@@ -1763,6 +1764,23 @@ int default_wake_function(wait_queue_t *
 
 EXPORT_SYMBOL(default_wake_function);
 
+asmlinkage void user_schedule(void)
+{
+#ifdef CONFIG_KGDB_THREAD
+	current->thread.debuggerinfo = NULL;
+#endif
+	do_schedule();
+}
+
+#ifdef CONFIG_KGDB_THREAD
+asmlinkage void kern_do_schedule(struct pt_regs regs)
+{
+	current->thread.debuggerinfo = &regs;
+	do_schedule();
+	current->thread.debuggerinfo = NULL;
+}
+#endif
+
 /*
  * The core wakeup function.  Non-exclusive wakeups (nr_exclusive == 0) just
  * wake everything up.  If it's an exclusive wakeup (nr_exclusive == small +ve
@@ -2961,6 +2979,8 @@ void __might_sleep(char *file, int line)
 #if defined(in_atomic)
 	static unsigned long prev_jiffy;	/* ratelimiting */
 
+	if (atomic_read(&debugger_active))
+		return;
 	if ((in_atomic() || irqs_disabled()) && system_running) {
 		if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
 			return;

-- 
Tom Rini
http://gate.crashing.org/~trini/

^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [PATCH][1/6] A different KGDB stub
  2004-02-17 22:02 [PATCH][1/6] A different KGDB stub Tom Rini
@ 2004-02-17 23:50 ` Andrew Morton
  2004-02-18  0:03   ` Tom Rini
  2004-02-18 19:36 ` Pavel Machek
  1 sibling, 1 reply; 9+ messages in thread
From: Andrew Morton @ 2004-02-17 23:50 UTC (permalink / raw)
  To: Tom Rini; +Cc: linux-kernel

Tom Rini <trini@kernel.crashing.org> wrote:
>
> The following is the core bits to this KGDB stub.

This still contains the kern_do_schedule() gunk.  Andi raised this issue
last week.  He identified several other significant issues as well, but
there was no followup.  Could you please dig out his email and address the
points which he raised?  (I can't find the email - perhaps Andi could
re-review this patch?)

^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [PATCH][1/6] A different KGDB stub
  2004-02-17 23:50 ` Andrew Morton
@ 2004-02-18  0:03   ` Tom Rini
  2004-02-18  0:33     ` Andrew Morton
  0 siblings, 1 reply; 9+ messages in thread
From: Tom Rini @ 2004-02-18  0:03 UTC (permalink / raw)
  To: Andrew Morton; +Cc: linux-kernel

On Tue, Feb 17, 2004 at 03:50:36PM -0800, Andrew Morton wrote:

> Tom Rini <trini@kernel.crashing.org> wrote:
> >
> > The following is the core bits to this KGDB stub.
> 
> This still contains the kern_do_schedule() gunk.  Andi raised this issue
> last week.  He identified several other significant issues as well, but
> there was no followup.  Could you please dig out his email and address the
> points which he raised?  (I can't find the email - perhaps Andi could
> re-review this patch?)

By my read of Andi's email, the kern_do_schedule() gunk is "I really
don't like this change. It is completely useless because you can get the
pt_regs as well from the stack.  Please don't add it. George's stub also
didn't need it."

But I don't see how it does.  But I'll look again tomorrow.

The next issue was about adding debuggerinfo to thread_struct.  By my
read of the code, it's because of the thread handling bits that Amit's
version does that George's does not.  So I'm not sure how it's not
needed (unless all of the relevant code goes.  If that's too heavy, I
can remove all of that).

Next was that KGDB should use the notify_die hooks that are there, and
I've done that.

Finally, the save_context_frame stuff can go (x86_64-specific stuffs)
but as I don't have x86_64 hw (I'll try and whip up a toolchain
tomorrow, but I leave for FOSDEM Thursday) so I didn't touch that, in
hopes that someone who could test it would.

-- 
Tom Rini
http://gate.crashing.org/~trini/

^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [PATCH][1/6] A different KGDB stub
  2004-02-18  0:03   ` Tom Rini
@ 2004-02-18  0:33     ` Andrew Morton
  2004-02-18  0:39       ` Tom Rini
  2004-02-25 17:50       ` Tom Rini
  0 siblings, 2 replies; 9+ messages in thread
From: Andrew Morton @ 2004-02-18  0:33 UTC (permalink / raw)
  To: Tom Rini; +Cc: linux-kernel

Tom Rini <trini@kernel.crashing.org> wrote:
>
> By my read of Andi's email, the kern_do_schedule() gunk is "I really
> don't like this change. It is completely useless because you can get the
> pt_regs as well from the stack.  Please don't add it. George's stub also
> didn't need it."
> 
> But I don't see how it does.  But I'll look again tomorrow.

OK, thanks.  That would be appreciated, if only because the sched.c and
entry.S changes have caused significant patch-conflict hassles in the past,
and they're pretty ugly.

Plus the little fact that the patch which you sent broke all other
architectures: they call schedule() from assembly code, and schedule()
ain't there any more.

I'll have a play with the patches which you sent, and if they don't break
I'll add them to -mm and I'll kludgily fix ppc64 and ia64 (if needed).  Be
aware that I removed the (large amount of) trailing whitespace which they
added.

^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [PATCH][1/6] A different KGDB stub
  2004-02-18  0:33     ` Andrew Morton
@ 2004-02-18  0:39       ` Tom Rini
  2004-02-25 17:50       ` Tom Rini
  1 sibling, 0 replies; 9+ messages in thread
From: Tom Rini @ 2004-02-18  0:39 UTC (permalink / raw)
  To: Andrew Morton; +Cc: linux-kernel

On Tue, Feb 17, 2004 at 04:33:12PM -0800, Andrew Morton wrote:
> Tom Rini <trini@kernel.crashing.org> wrote:
> >
> > By my read of Andi's email, the kern_do_schedule() gunk is "I really
> > don't like this change. It is completely useless because you can get the
> > pt_regs as well from the stack.  Please don't add it. George's stub also
> > didn't need it."
> > 
> > But I don't see how it does.  But I'll look again tomorrow.
> 
> OK, thanks.  That would be appreciated, if only because the sched.c and
> entry.S changes have caused significant patch-conflict hassles in the past,
> and they're pretty ugly.
> 
> Plus the little fact that the patch which you sent broke all other
> architectures: they call schedule() from assembly code, and schedule()
> ain't there any more.

Oh yeah, that, damnit.

> I'll have a play with the patches which you sent, and if they don't break
> I'll add them to -mm and I'll kludgily fix ppc64 and ia64 (if needed).  Be
> aware that I removed the (large amount of) trailing whitespace which they
> added.

I guess I forgot to Lindent everything.  I'll probably have new drop-in
patches a few more times (as opposed to incremental to the previous) a
few more times, so I'll make sure to fix that for next time.

-- 
Tom Rini
http://gate.crashing.org/~trini/

^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [PATCH][1/6] A different KGDB stub
  2004-02-18  0:33     ` Andrew Morton
  2004-02-18  0:39       ` Tom Rini
@ 2004-02-25 17:50       ` Tom Rini
  1 sibling, 0 replies; 9+ messages in thread
From: Tom Rini @ 2004-02-25 17:50 UTC (permalink / raw)
  To: Andrew Morton; +Cc: linux-kernel

On Tue, Feb 17, 2004 at 04:33:12PM -0800, Andrew Morton wrote:

> Tom Rini <trini@kernel.crashing.org> wrote:
> >
> > By my read of Andi's email, the kern_do_schedule() gunk is "I really
> > don't like this change. It is completely useless because you can get the
> > pt_regs as well from the stack.  Please don't add it. George's stub also
> > didn't need it."
> > 
> > But I don't see how it does.  But I'll look again tomorrow.
> 
> OK, thanks.  That would be appreciated, if only because the sched.c and
> entry.S changes have caused significant patch-conflict hassles in the past,
> and they're pretty ugly.

Two things:
- I've looked harder, and I still don't see some pre-exiting get pt_regs
  off the stack func / macro.  But it would probably be generally useful
  since it _looks_ like there's few places it could be used.  Or maybe I
  misread something and just missed it (not being an i386 person, it's
  possible :))
- The current plan for KGDB stuffs is to punt on the thread stuffs for
  now anyhow, so we can look at this again later.

-- 
Tom Rini
http://gate.crashing.org/~trini/

^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [PATCH][1/6] A different KGDB stub
  2004-02-17 22:02 [PATCH][1/6] A different KGDB stub Tom Rini
  2004-02-17 23:50 ` Andrew Morton
@ 2004-02-18 19:36 ` Pavel Machek
  2004-02-18 20:23   ` Tom Rini
  1 sibling, 1 reply; 9+ messages in thread
From: Pavel Machek @ 2004-02-18 19:36 UTC (permalink / raw)
  To: Tom Rini; +Cc: Andrew Morton, Kernel Mailing List

Hi!

> The following is the core bits to this KGDB stub.

What are those weak functions good for? Can't we simply assume that
any architecture that allows CONFIG_KGDB provides neccessary
functions?
								Pavel
PS: Also.. how to proceed? Should I split your patches into "normal"
and "lite" parts and submit to Amit?

-- 
When do you have a heart between your knees?
[Johanka's followup: and *two* hearts?]

^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [PATCH][1/6] A different KGDB stub
  2004-02-18 19:36 ` Pavel Machek
@ 2004-02-18 20:23   ` Tom Rini
  0 siblings, 0 replies; 9+ messages in thread
From: Tom Rini @ 2004-02-18 20:23 UTC (permalink / raw)
  To: Pavel Machek; +Cc: Andrew Morton, Kernel Mailing List

On Wed, Feb 18, 2004 at 08:36:24PM +0100, Pavel Machek wrote:

> Hi!
> 
> > The following is the core bits to this KGDB stub.
> 
> What are those weak functions good for? Can't we simply assume that
> any architecture that allows CONFIG_KGDB provides neccessary
> functions?

Not all arches need all functions, and that's where the weak functions
come in.  We could remove some of them (the *gdb*regs* type ones) as
being absolutely required, but not everyone needs kgdb_arch_init.
Similarly for kgdb_flush_io.

> PS: Also.. how to proceed? Should I split your patches into "normal"
> and "lite" parts and submit to Amit?

Tomorrow I leave for FOSDEM, and won't have time to pick on KGDB until I
get back Tuesday.  What I'm going to do then, if no one beats me to it,
is to merge stuff I've got into Amit's patches (the CVS versions off of
sourceforge), except for netpoll-specific portions of the kgdboe patch.

-- 
Tom Rini
http://gate.crashing.org/~trini/

^ permalink raw reply	[flat|nested] 9+ messages in thread

* [PATCH][1/6] A different KGDB stub
@ 2004-02-12  0:02 Tom Rini
  0 siblings, 0 replies; 9+ messages in thread
From: Tom Rini @ 2004-02-12  0:02 UTC (permalink / raw)
  To: Andrew Morton, Kernel Mailing List

The following is the core bits to this KGDB stub.

 Makefile                 |    2 
 include/linux/bitops.h   |    5 
 include/linux/debugger.h |   67 ++
 include/linux/kgdb.h     |  127 ++++
 include/linux/sched.h    |   13 
 init/main.c              |    2 
 kernel/Kconfig.kgdb      |  107 +++
 kernel/Makefile          |    1 
 kernel/kgdbstub.c        | 1279 +++++++++++++++++++++++++++++++++++++++++++++++
 kernel/module.c          |   10 
 kernel/sched.c           |   22 
 11 files changed, 1631 insertions(+), 4 deletions(-)
--- a/Makefile	Wed Feb 11 15:41:28 2004
+++ b/Makefile	Wed Feb 11 15:41:28 2004
@@ -440,6 +440,8 @@
 
 ifndef CONFIG_FRAME_POINTER
 CFLAGS		+= -fomit-frame-pointer
+else
+CFLAGS		+= -fno-omit-frame-pointer
 endif
 
 ifdef CONFIG_DEBUG_INFO
--- a/include/linux/bitops.h	Wed Feb 11 15:41:28 2004
+++ b/include/linux/bitops.h	Wed Feb 11 15:41:28 2004
@@ -108,7 +108,7 @@
         return (res & 0x0F) + ((res >> 4) & 0x0F);
 }
 
-static inline unsigned long generic_hweight64(__u64 w)
+static inline unsigned int generic_hweight64(__u64 w)
 {
 #if BITS_PER_LONG < 64
 	return generic_hweight32((unsigned int)(w >> 32)) +
@@ -120,7 +120,8 @@
 	res = (res & 0x0F0F0F0F0F0F0F0F) + ((res >> 4) & 0x0F0F0F0F0F0F0F0F);
 	res = (res & 0x00FF00FF00FF00FF) + ((res >> 8) & 0x00FF00FF00FF00FF);
 	res = (res & 0x0000FFFF0000FFFF) + ((res >> 16) & 0x0000FFFF0000FFFF);
-	return (res & 0x00000000FFFFFFFF) + ((res >> 32) & 0x00000000FFFFFFFF);
+	res = (res & 0x00000000FFFFFFFF) + ((res >> 32) & 0x00000000FFFFFFFF);
+	return (unsigned int)res;
 #endif
 }
 
--- /dev/null	Wed Dec 31 16:00:00 1969
+++ b/include/linux/debugger.h	Wed Feb 11 15:41:28 2004
@@ -0,0 +1,67 @@
+#ifndef _DEBUGGER_H_
+#define _DEBUGGER_H_
+
+/*
+ * Copyright (C) 2003-2004 Amit S. Kale
+ *
+ * Definition switchout for debuggers
+ */
+
+/*
+ * KGDB
+ */
+#ifdef CONFIG_KGDB
+
+typedef int gdb_debug_hook(int exVector, int signo, int err_code,
+                            struct pt_regs *regs);
+extern gdb_debug_hook  *linux_debug_hook;
+#define	CHK_DEBUGGER(trapnr,signr,error_code,regs,after)			\
+    {									\
+	if (linux_debug_hook != (gdb_debug_hook *) NULL && !user_mode(regs)) \
+	{								\
+		(*linux_debug_hook)(trapnr, signr, error_code, regs) ;	\
+		after;							\
+	}								\
+    }
+
+void kgdb_nmihook(int cpu, void *regs);
+static inline void debugger_nmihook(int cpu, void *regs)
+{
+	kgdb_nmihook(cpu, regs);
+}
+
+void kgdb_entry(void);
+static inline void debugger_entry(void)
+{
+	kgdb_entry();
+}
+
+extern int debugger_step;
+extern atomic_t debugger_active;
+extern volatile int debugger_memerr_expected;
+
+/*
+ * No debugger in the kernel
+ */
+#else
+
+#define	CHK_DEBUGGER(trapnr,signr,error_code,regs,after)	
+
+static inline void debugger_nmihook(int cpu, void *regs)
+{
+	/* Do nothing */
+}
+
+static inline void debugger_entry(void)
+{
+	/* Do nothing */
+}
+
+#define debugger_step 0
+static const atomic_t debugger_active = { 0 };
+#define debugger_memerr_expected 0
+
+#endif
+
+
+#endif /* _DEBUGGER_H_ */
--- /dev/null	Wed Dec 31 16:00:00 1969
+++ b/include/linux/kgdb.h	Wed Feb 11 15:41:28 2004
@@ -0,0 +1,127 @@
+#ifndef _KGDB_H_
+#define _KGDB_H_
+
+/*
+ * Copyright (C) 2001-2004 Amit S. Kale
+ */
+
+#include <linux/ptrace.h>
+#include <asm/kgdb.h>
+#include <linux/spinlock.h>
+#include <asm/atomic.h>
+#include <linux/debugger.h>
+
+/*
+ * This file should not include ANY others.  This makes it usable
+ * most anywhere without the fear of include order or inclusion.
+ * TODO: Make it so!
+ *
+ * This file may be included all the time.  It is only active if
+ * CONFIG_KGDB is defined, otherwise it stubs out all the macros
+ * and entry points.
+ */
+
+#if defined(CONFIG_KGDB) && !defined(__ASSEMBLY__)
+/* To enter the debugger explicitly. */
+extern void breakpoint(void);
+extern void kgdb_schedule_breakpoint(void);
+extern void kgdb_process_breakpoint(void);
+extern volatile int kgdb_connected;
+
+#ifndef KGDB_MAX_NO_CPUS
+#if CONFIG_NR_CPUS > 8
+#error KGDB can handle max 8 CPUs
+#endif
+#define KGDB_MAX_NO_CPUS 8
+#endif
+
+
+extern struct task_struct *kgdb_usethread, *kgdb_contthread;
+
+enum gdb_bptype
+{
+	bp_breakpoint = '0',
+	bp_hardware_breakpoint,
+	bp_write_watchpoint,
+	bp_read_watchpoint,
+	bp_access_watchpoint
+};
+
+enum gdb_bpstate
+{
+       bp_disabled,
+       bp_enabled
+};
+
+#ifndef BREAK_INSTR_SIZE
+#error BREAK_INSTR_SIZE  needed by kgdb
+#endif
+
+struct gdb_breakpoint
+{
+       unsigned long            bpt_addr;
+       unsigned char           saved_instr[BREAK_INSTR_SIZE];
+       enum gdb_bptype         type;
+       enum gdb_bpstate        state;
+};
+
+typedef struct gdb_breakpoint gdb_breakpoint_t;
+
+#ifndef MAX_BREAKPOINTS
+#define MAX_BREAKPOINTS        16
+#endif
+
+#define KGDB_HW_BREAKPOINT          1
+
+/* These are functions that the arch specific code can, and in some cases
+ * must, provide. */
+extern int kgdb_arch_init(void);
+extern void regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs);
+extern void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs,struct task_struct *p);
+extern void gdb_regs_to_regs(unsigned long *gdb_regs, struct pt_regs *regs);
+extern void kgdb_printexceptioninfo(int exceptionNo, int errorcode,
+		char *buffer);
+extern void kgdb_disable_hw_debug(struct pt_regs *regs);
+extern void kgdb_post_master_code(struct pt_regs *regs, int eVector,
+		int err_code);
+extern int kgdb_arch_handle_exception(int vector, int signo, int err_code,
+		char *InBuffer, char *outBuffer, struct pt_regs *regs);
+extern int kgdb_arch_set_break(unsigned long addr, int type);
+extern int kgdb_arch_remove_break(unsigned long addr, int type);
+extern void kgdb_correct_hw_break(void);
+extern void kgdb_shadowinfo(struct pt_regs *regs, char *buffer, unsigned threadid);
+extern struct task_struct *kgdb_get_shadow_thread(struct pt_regs *regs,
+		int threadid);
+extern struct pt_regs *kgdb_shadow_regs(struct pt_regs *regs, int threadid);
+
+struct kgdb_arch {
+	unsigned char gdb_bpt_instr[BREAK_INSTR_SIZE];
+	unsigned long flags;
+	unsigned shadowth;
+};			
+
+/* Thread reference */
+typedef unsigned char threadref[8];
+
+struct kgdb_serial {
+	int (*read_char)(void);
+	void (*write_char)(int);
+	void (*flush)(void);
+	int (*hook)(void);
+};
+
+extern struct kgdb_serial *kgdb_serial;
+extern struct kgdb_arch arch_kgdb_ops;
+extern int kgdb_initialized;
+
+struct uart_port;
+
+extern void kgdb8250_add_port(int i, struct uart_port *serial_req);
+
+int kgdb_hexToLong(char **ptr, long *longValue);
+char *kgdb_mem2hex(char *mem, char *buf, int count, int can_fault);
+
+#else
+#define kgdb_process_breakpoint()	do {} while(0)
+#endif /* KGDB && !__ASSEMBLY__ */
+#endif /* _KGDB_H_ */
--- a/include/linux/sched.h	Wed Feb 11 15:41:28 2004
+++ b/include/linux/sched.h	Wed Feb 11 15:41:28 2004
@@ -175,7 +175,9 @@
 
 #define	MAX_SCHEDULE_TIMEOUT	LONG_MAX
 extern signed long FASTCALL(schedule_timeout(signed long timeout));
-asmlinkage void schedule(void);
+asmlinkage void do_schedule(void);
+asmlinkage void kern_schedule(void);
+asmlinkage void kern_do_schedule(struct pt_regs);
 
 struct namespace;
 
@@ -1027,6 +1029,15 @@
 }
 
 #endif /* CONFIG_SMP */
+
+static inline void schedule(void)
+{
+#ifdef CONFIG_KGDB_THREAD
+	kern_schedule();
+#else
+	do_schedule();
+#endif
+}
 
 #endif /* __KERNEL__ */
 
--- a/init/main.c	Wed Feb 11 15:41:28 2004
+++ b/init/main.c	Wed Feb 11 15:41:28 2004
@@ -39,6 +39,7 @@
 #include <linux/writeback.h>
 #include <linux/cpu.h>
 #include <linux/efi.h>
+#include <linux/debugger.h>
 
 #include <asm/io.h>
 #include <asm/bugs.h>
@@ -603,6 +604,7 @@
 	smp_init();
 	sched_init_smp();
 	do_basic_setup();
+	debugger_entry();
 
 	/*
 	 * check if there is an early userspace init, if yes
--- /dev/null	Wed Dec 31 16:00:00 1969
+++ b/kernel/Kconfig.kgdb	Wed Feb 11 15:41:28 2004
@@ -0,0 +1,107 @@
+config KGDB
+	bool "KGDB: kernel debugging with remote gdb"
+	depends on DEBUG_KERNEL
+	select DEBUG_INFO
+	select FRAME_POINTER
+	# XXX: Doesn't work w/o this right now
+	select KGDB_THREAD if PPC32
+	help
+	  If you say Y here, it will be possible to remotely debug the
+	  kernel using gdb. This enlarges your kernel image disk size by
+	  several megabytes and requires a machine with more than 128 MB
+	  RAM to avoid excessive linking time. 
+	  Documentation of kernel debugger available at
+	  http://kgdb.sourceforge.net
+	  This is only useful for kernel hackers. If unsure, say N.
+
+config KGDB_SIMPLE_SERIAL
+	bool "Simple selection of KGDB serial port"
+	depends on KGDB
+	help
+	  If you say Y here, you will only have to pick the baud rate
+	  and serial port (ttyS) that you wish to use for KGDB.  If you
+	  say N, you will have provide the I/O port and IRQ number.  Note
+	  that if your serial ports are iomapped, then you must say Y here.
+	  If in doubt, say Y.
+
+choice
+	depends on KGDB
+    	prompt "Debug serial port BAUD"
+	default KGDB_115200BAUD
+	help
+	  Gdb and the kernel stub need to agree on the baud rate to be
+	  used.  Some systems (x86 family at this writing) allow this to
+	  be configured.
+
+config KGDB_9600BAUD
+	bool "9600"
+
+config KGDB_19200BAUD
+	bool "19200"
+
+config KGDB_38400BAUD
+	bool "38400"
+
+config KGDB_57600BAUD
+	bool "57600"
+
+config KGDB_115200BAUD
+	bool "115200"
+endchoice
+
+choice
+	prompt "Serial port for KGDB"
+	depends on KGDB && KGDB_SIMPLE_SERIAL
+	default KGDB_TTYS0
+
+config KGDB_TTYS0
+	bool "ttyS0"
+
+config KGDB_TTYS1
+	bool "ttyS1"
+
+config KGDB_TTYS2
+	bool "ttyS2"
+
+config KGDB_TTYS3
+	bool "ttyS3"
+
+endchoice
+
+config KGDB_PORT
+	hex "hex I/O port address of the debug serial port"
+	depends on KGDB && !KGDB_SIMPLE_SERIAL
+	default  3f8
+	help
+	  Some systems (x86 family at this writing) allow the port
+	  address to be configured.  The number entered is assumed to be
+	  hex, don't put 0x in front of it.  The standard address are:
+	  COM1 3f8 , irq 4 and COM2 2f8 irq 3.  Setserial /dev/ttySx
+	  will tell you what you have.  It is good to test the serial
+	  connection with a live system before trying to debug.
+
+config KGDB_IRQ
+	int "IRQ of the debug serial port"
+	depends on KGDB && !KGDB_SIMPLE_SERIAL
+	default 4
+	help
+	  This is the irq for the debug port.  If everything is working
+	  correctly and the kernel has interrupts on a control C to the
+	  port should cause a break into the kernel debug stub.
+
+config KGDB_THREAD
+	bool "KGDB: Thread analysis"
+	depends on KGDB
+	help
+	  With thread analysis enabled, gdb can talk to kgdb stub to list
+	  threads and to get stack trace for a thread. This option also enables
+	  some code which helps gdb get exact status of thread. Thread analysis
+	  adds some overhead to schedule and down functions. You can disable
+	  this option if you do not want to compromise on speed.
+
+config KGDB_CONSOLE
+	bool "KGDB: Console messages through gdb"
+	depends on KGDB
+	help
+	  If you say Y here, console messages will appear through gdb.
+	  Other consoles such as tty or ttyS will continue to work as usual.
--- a/kernel/Makefile	Wed Feb 11 15:41:28 2004
+++ b/kernel/Makefile	Wed Feb 11 15:41:28 2004
@@ -21,6 +21,7 @@
 obj-$(CONFIG_COMPAT) += compat.o compat_signal.o
 obj-$(CONFIG_IKCONFIG) += configs.o
 obj-$(CONFIG_IKCONFIG_PROC) += configs.o
+obj-$(CONFIG_KGDB) += kgdbstub.o
 
 ifneq ($(CONFIG_IA64),y)
 # According to Alan Modra <alan@linuxcare.com.au>, the -fno-omit-frame-pointer is
--- /dev/null	Wed Dec 31 16:00:00 1969
+++ b/kernel/kgdbstub.c	Wed Feb 11 15:41:28 2004
@@ -0,0 +1,1279 @@
+/*
+ * 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) 2000-2001 VERITAS Software Corporation.
+ * Copyright (C) 2002-2004 Timesys Corporation
+ * Copyright (C) 2003-2004 Amit S. Kale
+ * Copyright (C) 2004 Pavel Machek <pavel@suse.cz>
+ *
+ * Restructured KGDB for 2.6 kernels.
+ * thread support, support for multiple processors,support for ia-32(x86) 
+ * hardware debugging, Console support, handling nmi watchdog
+ * - Amit S. Kale ( amitkale@emsyssoft.com )
+ *
+ * Several enhancements by George Anzinger <george@mvista.com>
+ * Generic KGDB Support
+ * Implemented by Anurekh Saxena (anurekh.saxena@timesys.com)
+ * 
+ * Contributor:     Lake Stevens Instrument Division
+ * Written by:      Glenn Engel
+ *  
+ * Modified for 386 by Jim Kingdon, Cygnus Support.
+ * Origianl kgdb, compatibility with 2.1.xx kernel by David Grothe <dave@gcom.com>
+ * Integrated into 2.2.5 kernel by Tigran Aivazian <tigran@sco.com>
+ */
+
+#include <linux/string.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/smp.h>
+#include <linux/spinlock.h>
+#include <linux/delay.h>
+#include <linux/mm.h>
+#include <asm/system.h>
+#include <asm/ptrace.h>		/* for linux pt_regs struct */
+#include <asm/uaccess.h>
+#include <linux/kgdb.h>
+#include <asm/atomic.h>
+#include <linux/notifier.h>
+#include <linux/module.h>
+#include <asm/cacheflush.h>
+
+#ifdef CONFIG_KGDB_CONSOLE
+#include <linux/console.h>
+#endif
+ 
+#include <linux/init.h>
+
+/*
+ * The following are the stub functions for code which is arch specific
+ * and can be omitted on some arches
+ */
+
+/*
+ * This function will handle the initalization of any architecture specific
+ * hooks.  If there is a suitable early output driver, kgdb_serial
+ * can be pointed at it now.
+ */
+int __attribute__ ((weak))
+kgdb_arch_init(void)
+{
+	/* If we have the default serial driver, set that to be the
+	 * output now. */
+#ifdef CONFIG_KGDB_8250
+	extern struct kgdb_serial kgdb8250_serial_driver;
+	kgdb_serial = &kgdb8250_serial_driver;
+#endif
+
+	return 0;
+}
+
+void __attribute__ ((weak))
+regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
+{
+}
+
+void __attribute__ ((weak))
+sleeping_thread_to_gdb_regs(unsigned long *gdb_regs,struct task_struct *p)
+{
+}
+
+void __attribute__ ((weak))
+gdb_regs_to_regs(unsigned long *gdb_regs, struct pt_regs *regs)
+{
+}
+
+void __attribute__ ((weak))
+kgdb_printexceptioninfo(int exceptionNo, int errorcode, char *buffer)
+{
+}
+
+void __attribute__ ((weak))
+kgdb_disable_hw_debug(struct pt_regs *regs)
+{
+}
+
+void __attribute__ ((weak))
+kgdb_post_master_code(struct pt_regs *regs, int eVector, int err_code)
+{
+}
+
+/*
+ * Handle any additional commands.  This must handle the 'c' and 's'
+ * command packets.
+ * Return -1 to loop over other commands, and 0 to exit from KGDB
+ */
+int __attribute__ ((weak))
+kgdb_arch_handle_exception(int vector, int signo, int err_code, char *InBuffer,
+		char *outBuffer, struct pt_regs *regs)
+{
+	return -1;	/* Do not exit from the handler. */
+}
+
+int __attribute__ ((weak))
+kgdb_arch_set_break(unsigned long addr, int type)
+{
+	return 0;
+}
+
+int __attribute__ ((weak))
+kgdb_arch_remove_break(unsigned long addr, int type)
+{
+	return 0;
+}
+
+void __attribute__ ((weak))
+kgdb_correct_hw_break(void)
+{
+}
+
+void __attribute__ ((weak))
+kgdb_shadowinfo(struct pt_regs *regs, char *buffer, unsigned threadid)
+{
+}
+
+struct task_struct __attribute__ ((weak))
+*kgdb_get_shadow_thread(struct pt_regs *regs, int threadid)
+{
+	return NULL;
+}
+
+struct pt_regs __attribute__ ((weak))
+*kgdb_shadow_regs(struct pt_regs *regs, int threadid)
+{
+	return NULL;
+}
+
+struct kgdb_arch *kgdb_ops = &arch_kgdb_ops;
+gdb_breakpoint_t kgdb_break[MAX_BREAKPOINTS];
+extern int pid_max;
+
+struct kgdb_serial *kgdb_serial;
+
+int kgdb_initialized = 0;
+int kgdb_enter = 0;
+static const char hexchars[] = "0123456789abcdef";
+
+static int get_char(char *addr, unsigned char *data, int can_fault);
+static int set_char(char *addr, int data, int can_fault);
+
+spinlock_t slavecpulocks[KGDB_MAX_NO_CPUS];
+static volatile int procindebug[KGDB_MAX_NO_CPUS];
+atomic_t kgdb_setting_breakpoint;
+volatile int kgdb_connected;
+struct task_struct *kgdb_usethread, *kgdb_contthread;
+
+int debugger_step;
+atomic_t debugger_active;
+
+/* 
+ * Indicate to caller of kgdb_mem2hex or hex2mem that there has been an
+ * error.  
+ */
+volatile int kgdb_memerr = 0;
+volatile int debugger_memerr_expected = 0;
+
+/* This will point to kgdb_handle_exception by default.
+ * The architecture code can override this in its init function
+ */
+gdb_debug_hook *linux_debug_hook;
+
+
+static char remcomInBuffer[BUFMAX];
+static char remcomOutBuffer[BUFMAX];
+static short error;
+
+static int module_event(struct notifier_block * self, unsigned long val,
+		void * data);
+
+static struct notifier_block kgdb_module_load_nb = {
+	.notifier_call = module_event,
+};
+
+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 $<data>#<checksum>	*/
+static void
+getpacket(char *buffer)
+{
+	unsigned char checksum;
+	unsigned char xmitcsum;
+	int count;
+	char ch;
+
+	do {
+	/* wait around for the start character, ignore all other characters */
+		while ((ch = (kgdb_serial->read_char() & 0x7f)) != '$')
+			;	/* Spin */
+		kgdb_connected = 1;
+		checksum = 0;
+		xmitcsum = -1;
+
+		count = 0;
+
+		/* now, read until a # or end of buffer is found */
+		while (count < BUFMAX) {
+			ch = kgdb_serial->read_char() & 0x7f;
+			if (ch == '#')
+				break;
+			checksum = checksum + ch;
+			buffer[count] = ch;
+			count = count + 1;
+		}
+		buffer[count] = 0;
+
+		if (ch == '#') {
+			xmitcsum = hex(kgdb_serial->read_char() & 0x7f) << 4;
+			xmitcsum += hex(kgdb_serial->read_char() & 0x7f);
+
+			if (checksum != xmitcsum)
+				/* Retransmit. */
+				kgdb_serial->write_char('-');
+			else
+				/* ACK. */
+				kgdb_serial->write_char('+');
+
+			if (kgdb_serial->flush)
+				kgdb_serial->flush();
+		}
+	} while (checksum != xmitcsum);
+}
+
+
+/*
+ * Send the packet in buffer.
+ * Check for gdb connection if asked for.
+ */
+static void
+putpacket(char *buffer)
+{
+	unsigned char checksum;
+	int count;
+	char ch;
+
+	/*  $<packet info>#<checksum>. */
+	do {
+		checksum = 0;
+		count = 0;
+
+		/* Write out the packet. */
+		kgdb_serial->write_char('$');
+		while ((ch = buffer[count])) {
+			kgdb_serial->write_char(ch);
+			checksum += ch;
+			count++;
+		}
+
+		kgdb_serial->write_char('#');
+		kgdb_serial->write_char(hexchars[checksum >> 4]);
+		kgdb_serial->write_char(hexchars[checksum % 16]);
+		if (kgdb_serial->flush)
+			kgdb_serial->flush();
+	} while ((kgdb_serial->read_char() & 0x7f) != '+');
+}
+
+/*
+ * convert the memory pointed to by mem into hex, placing result in buf
+ * return a pointer to the last char put in buf (null)
+ * If MAY_FAULT is non-zero, then we should set kgdb_memerr in response to
+ * a fault; if zero treat a fault like any other fault in the stub.
+ */
+char *kgdb_mem2hex(char *mem, char *buf, int count, int can_fault)
+{
+	int i;
+	unsigned char ch;
+	
+	for (i = 0; i < count; i++) {
+
+		if (get_char(mem++, &ch, can_fault) < 0) 
+			break;
+		
+		*buf++ = hexchars[ch >> 4];
+		*buf++ = hexchars[ch % 16];
+	}
+	*buf = 0;
+	return (buf);
+}
+
+/* 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 */
+
+char *hex2mem(char *buf, char *mem, int count, int can_fault)
+{
+	int i;
+	unsigned char ch;
+	
+	for (i = 0; i < count; i++) {
+		ch = hex(*buf++) << 4;
+		ch = ch + hex(*buf++);
+		if (set_char(mem++, ch, can_fault) < 0) 
+			break;
+	}
+	return (mem);
+}
+
+/*
+ * While we find nice hex chars, build a longValue.
+ * Return number of chars processed.
+ */
+int kgdb_hexToLong(char **ptr, long *longValue)
+{
+	int numChars = 0;
+	int hexValue;
+
+	*longValue = 0;
+
+	while (**ptr) {
+		hexValue = hex(**ptr);
+		if (hexValue >= 0) {
+			*longValue = (*longValue << 4) | hexValue;
+			numChars++;
+		} else
+			break;
+
+		(*ptr)++;
+	}
+
+	return (numChars);
+}
+
+static inline char *pack_hex_byte(char *pkt, int byte)
+{
+	*pkt++ = hexchars[(byte >> 4) & 0xf];
+	*pkt++ = hexchars[(byte & 0xf)];
+	return pkt;
+}
+
+#define BUF_THREAD_ID_SIZE 16
+
+static char *pack_threadid(char *pkt, threadref *id)
+{
+	char *limit;
+	unsigned char *altid;
+
+	altid = (unsigned char *) id;
+	limit = pkt + BUF_THREAD_ID_SIZE;
+	while (pkt < limit)
+		pkt = pack_hex_byte(pkt, *altid++);
+
+	return pkt;
+}
+
+void int_to_threadref(threadref *id, int value)
+{
+	unsigned char *scan;
+
+	scan = (unsigned char *) id;
+	{
+		int i = 4;
+		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)
+{
+	int i;
+	struct list_head *l;
+	struct task_struct *p;
+	struct pid *pid;
+
+	if (tid >= pid_max + num_online_cpus() + kgdb_ops->shadowth) {
+		return NULL;
+	}
+	if (tid >= pid_max + num_online_cpus()) {
+		return kgdb_get_shadow_thread(regs, tid - pid_max -
+				num_online_cpus());
+	}
+	if (tid >= pid_max) {
+		i = 0;
+		for_each_task_pid(0, PIDTYPE_PID, p, l, pid) {
+			if (tid == pid_max + i) {
+				return p;
+			}
+			i++;
+		}
+		return NULL;
+	}
+	if (!tid) {
+		return NULL;
+	}
+	return find_task_by_pid(tid);
+}
+
+#ifdef CONFIG_SMP
+void kgdb_wait(struct pt_regs *regs)
+{
+	unsigned long flags;
+	int processor;
+
+	local_irq_save(flags);
+	processor = smp_processor_id();
+	procindebug[processor] = 1;
+	current->thread.debuggerinfo = regs;
+
+	/* Wait till master processor goes completely into the debugger. FIXME: this looks racy */
+	while (!procindebug[atomic_read(&debugger_active) - 1]) {
+		int i = 10;	/* an arbitrary number */
+
+		while (--i)
+			asm volatile ("nop": : : "memory");
+		barrier();
+	}
+
+	/* Wait till master processor is done with debugging */
+	spin_lock(slavecpulocks + processor);
+
+	/* This has been taken from x86 kgdb implementation and
+	 * will be needed by architectures that have SMP support
+	 */
+	kgdb_correct_hw_break();
+
+	/* Signal the master processor that we are done */
+	procindebug[processor] = 0;
+	spin_unlock(slavecpulocks + processor);
+	local_irq_restore(flags);
+}
+#endif
+
+static void get_mem (char *addr, unsigned char *buf, int count)
+{
+	while (count) {
+		if(get_char(addr++, buf, 1) <  0) 
+			return;
+		buf++;
+		count--;
+	}
+}
+
+static void set_mem (char *addr,unsigned char *buf, int count)
+{
+	while (count) {
+		if (set_char(addr++,*buf++, 1) < 0) 
+			return;
+		count--;
+	}
+}
+
+static int set_break (unsigned long addr)
+{
+	int i, breakno = -1;
+
+	for (i = 0; i < MAX_BREAKPOINTS; i++) {
+		if ((kgdb_break[i].state == bp_enabled) &&
+		    (kgdb_break[i].bpt_addr == addr)) {
+			breakno = -1;
+			break;
+		}
+
+		if (kgdb_break[i].state == bp_disabled) {
+			if ((breakno == -1) || (kgdb_break[i].bpt_addr == addr))
+				breakno = i;
+		}
+	}
+	if (breakno == -1)
+		return -1;
+
+	get_mem((char *)addr, kgdb_break[breakno].saved_instr, BREAK_INSTR_SIZE);
+	if (kgdb_memerr)
+		return -1;
+
+	set_mem((char *)addr, kgdb_ops->gdb_bpt_instr, BREAK_INSTR_SIZE);
+	flush_cache_range (current->mm, addr, addr + BREAK_INSTR_SIZE);
+	flush_icache_range (addr, addr + BREAK_INSTR_SIZE);
+	if (kgdb_memerr)
+		return -1;
+
+	kgdb_break[breakno].state = bp_enabled;
+	kgdb_break[breakno].type = bp_breakpoint;
+	kgdb_break[breakno].bpt_addr = addr;
+	
+	return 0;
+}	
+
+static int remove_break (unsigned long addr)
+{
+	int i;
+
+	for (i=0; i < MAX_BREAKPOINTS; i++) {
+		if ((kgdb_break[i].state == bp_enabled) &&
+		   (kgdb_break[i].bpt_addr == addr)) {
+			set_mem((char *)addr, kgdb_break[i].saved_instr,
+			        BREAK_INSTR_SIZE);
+			flush_cache_range (current->mm, addr, addr + BREAK_INSTR_SIZE);
+			flush_icache_range (addr, addr + BREAK_INSTR_SIZE);
+			if (kgdb_memerr)
+				return -1;
+			kgdb_break[i].state = bp_disabled;
+			return 0;
+		}
+	}
+	return -1;
+}
+
+int remove_all_break(void)
+{
+	int i;
+	for (i=0; i < MAX_BREAKPOINTS; i++) {
+		if(kgdb_break[i].state == bp_enabled) {
+			unsigned long addr = kgdb_break[i].bpt_addr;
+			set_mem((char *)addr, kgdb_break[i].saved_instr,
+			       BREAK_INSTR_SIZE);
+			flush_cache_range (current->mm, addr, addr + BREAK_INSTR_SIZE);
+			flush_icache_range (addr, addr + BREAK_INSTR_SIZE);
+		}
+		kgdb_break[i].state = bp_disabled;
+	}
+	return 0;
+}
+		
+int get_char(char *addr, unsigned char *data, int can_fault)
+{
+	mm_segment_t fs;
+	int ret = 0;
+	
+	kgdb_memerr = 0;
+	
+	if (can_fault)
+		debugger_memerr_expected = 1;
+	wmb();
+	fs = get_fs();
+	set_fs(KERNEL_DS);
+	
+	if (get_user(*data, addr) != 0) {
+		ret = -EFAULT;
+		kgdb_memerr = 1;
+	}
+	
+	debugger_memerr_expected = 0;	
+	set_fs(fs);
+	return ret;
+}
+
+int set_char(char *addr, int data, int can_fault)
+{
+	mm_segment_t fs;
+	int ret = 0;
+	
+	kgdb_memerr = 0;
+	
+	if (can_fault)
+		debugger_memerr_expected = 1;
+	wmb();
+	fs = get_fs();
+	set_fs(KERNEL_DS);
+
+	if (put_user(data, addr) != 0) {
+		ret = -EFAULT;
+		kgdb_memerr = 1;
+	}
+	
+	debugger_memerr_expected = 0;
+	set_fs(fs);
+	return ret;
+}
+
+static inline int shadow_pid(int realpid)
+{
+	if (realpid) {
+		return realpid;
+	}
+	return pid_max + smp_processor_id();
+}
+
+/*
+ * This function does all command procesing for interfacing to gdb.
+ *
+ * Locking hierarchy:
+ *	interface locks, if any (begin_session)
+ *	kgdb lock (debugger_active)
+ *
+ */
+int kgdb_handle_exception(int exVector, int signo, int err_code, 
+                     struct pt_regs *linux_regs)
+{
+	unsigned long length, addr;
+	char *ptr;
+	unsigned long flags;
+	unsigned long gdb_regs[NUMREGBYTES / sizeof (unsigned long)];
+	int i;
+	long threadid;
+	threadref thref;
+	struct task_struct *thread = NULL;
+	unsigned procid;
+	int ret = 0;
+	static char tmpstr[256];
+	int numshadowth = num_online_cpus() + kgdb_ops->shadowth;
+	long kgdb_usethreadid = 0;
+
+	/* Panic on recursive debugger calls. */
+	if (atomic_read(&debugger_active) == smp_processor_id() + 1) {
+		return 0;
+	}
+
+	/* 
+	 * Interrupts will be restored by the 'trap return' code, except when
+	 * single stepping.
+	 */
+	local_irq_save(flags);
+	
+	/* Hold debugger_active */
+	procid = smp_processor_id();
+	while (cmpxchg(&atomic_read(&debugger_active), 0, (procid + 1)) != 0) {
+		int i = 25;	/* an arbitrary number */
+
+		while (--i)
+			asm volatile ("nop": : : "memory");
+	}
+	
+	debugger_step = 0;
+
+	current->thread.debuggerinfo = linux_regs;
+
+	kgdb_disable_hw_debug(linux_regs);
+
+	for (i = 0; i < num_online_cpus(); i++) {
+		spin_lock(&slavecpulocks[i]);
+	}
+
+	/* spin_lock code is good enough as a barrier so we don't
+	 * need one here */
+	procindebug[smp_processor_id()] = 1;
+
+	/* Clear the out buffer. */
+	memset(remcomOutBuffer, 0, sizeof(remcomOutBuffer));
+
+	/* Master processor is completely in the debugger */
+	kgdb_post_master_code(linux_regs, exVector, err_code);
+
+	/* If kgdb is connected, then an exception has occured, and
+	 * we need to pass something back to GDB. */
+	if (kgdb_connected) {
+		ptr = remcomOutBuffer;
+		*ptr++ = 'T';
+		*ptr++ = hexchars[(signo >> 4) % 16];
+		*ptr++ = hexchars[signo % 16];
+		*ptr++ = hexchars[(PC_REGNUM >> 4) % 16];
+		*ptr++ = hexchars[PC_REGNUM % 16];
+		*ptr++ = ':';
+		ptr = kgdb_mem2hex((char *)&linux_regs->PTRACE_PC, ptr, 4, 0);
+		*ptr++ = ';';
+		*ptr++ = hexchars[SP_REGNUM >> 4];
+		*ptr++ = hexchars[SP_REGNUM & 0xf];
+		*ptr++ = ':';
+		ptr = kgdb_mem2hex(((char *)linux_regs) + SP_REGNUM * 4, ptr,
+				4, 0);
+		*ptr++ = ';';
+		ptr += strlen(strcpy(ptr, "thread:"));
+		int_to_threadref(&thref, shadow_pid(current->pid));
+		ptr = pack_threadid(ptr, &thref);
+		*ptr++ = ';';
+
+		putpacket(remcomOutBuffer);
+	}
+
+	kgdb_usethread = current;
+	kgdb_usethreadid = shadow_pid(current->pid);
+
+	while (1) {
+		int bpt_type = 0;
+		error = 0;
+
+		/* Clear the out buffer. */
+		memset(remcomOutBuffer, 0, sizeof(remcomOutBuffer));
+
+		getpacket(remcomInBuffer);
+
+#if KGDB_DEBUG
+		bust_spinlocks(1);
+		printk("CPU%d pid%d GDB packet: %s\n", 
+		       smp_processor_id(), current->pid, remcomInBuffer);
+		bust_spinlocks(0);
+#endif
+		switch (remcomInBuffer[0]) {
+		case '?':
+			/* reply to host that an exception has occurred */
+			ptr = remcomOutBuffer;
+			*ptr++ = 'T';
+			*ptr++ = hexchars[(signo >> 4) % 16];
+			*ptr++ = hexchars[signo % 16];
+			*ptr++ = hexchars[(PC_REGNUM >> 4) % 16];
+			*ptr++ = hexchars[PC_REGNUM % 16];
+			*ptr++ = ':';
+			ptr = kgdb_mem2hex((char *)&linux_regs->PTRACE_PC, ptr,
+					4, 0);
+			*ptr++ = ';';
+			*ptr++ = hexchars[SP_REGNUM >> 4];
+			*ptr++ = hexchars[SP_REGNUM & 0xf];
+			*ptr++ = ':';
+			ptr = kgdb_mem2hex(((char *)linux_regs) + SP_REGNUM * 4,
+					ptr, 4, 0);
+			*ptr++ = ';';
+			ptr += strlen(strcpy(ptr, "thread:"));
+			int_to_threadref(&thref, shadow_pid(current->pid));
+			ptr = pack_threadid(ptr, &thref);
+			*ptr++ = ';';
+			break;
+		case 'g':	/* return the value of the CPU registers */
+			thread = kgdb_usethread;
+				
+			if (!thread)
+				thread = current;
+			
+			/* 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 (kgdb_usethreadid >= pid_max + num_online_cpus()) {
+				regs_to_gdb_regs(gdb_regs,
+					kgdb_shadow_regs(linux_regs,
+						kgdb_usethreadid - pid_max -
+						num_online_cpus()));
+			} else if (thread->thread.debuggerinfo) {
+				if (get_char(thread->thread.debuggerinfo,
+					(unsigned char *)gdb_regs, 1)) {
+					strcpy(remcomOutBuffer, "E10");
+					break;
+				}
+				regs_to_gdb_regs(gdb_regs,
+					(struct pt_regs *)
+					thread->thread.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, remcomOutBuffer, NUMREGBYTES, 0);
+			break;
+
+		case 'G':	/* set the value of the CPU registers - return OK */
+			hex2mem(&remcomInBuffer[1], (char *) gdb_regs,
+				NUMREGBYTES, 0);
+				
+			if (kgdb_usethread && kgdb_usethread != current)
+				strcpy(remcomOutBuffer, "E00");
+			else {
+				gdb_regs_to_regs(gdb_regs,
+					(struct pt_regs *)
+					current->thread.debuggerinfo);
+				strcpy(remcomOutBuffer, "OK");
+			}
+
+			break;
+
+			/* mAA..AA,LLLL  Read LLLL bytes at address AA..AA */
+		case 'm':
+			/* TRY TO READ %x,%x.  IF SUCCEED, SET PTR = 0 */
+			ptr = &remcomInBuffer[1];
+			if (kgdb_hexToLong(&ptr, &addr) && *ptr++ == ',' &&
+			    kgdb_hexToLong(&ptr, &length)) {
+				ptr = 0;
+				kgdb_mem2hex((char *) addr, remcomOutBuffer, length, 1);
+				if (kgdb_memerr)
+					strcpy(remcomOutBuffer, "E03");
+					
+			}
+
+			if (ptr) 
+				strcpy(remcomOutBuffer, "E01");
+			break;
+
+		/* MAA..AA,LLLL: Write LLLL bytes at address AA.AA return OK */
+		case 'M':
+			/* TRY TO READ '%x,%x:'.  IF SUCCEED, SET PTR = 0 */
+			ptr = &remcomInBuffer[1];
+			if (kgdb_hexToLong(&ptr, &addr) && *(ptr++) == ',' && 
+			    kgdb_hexToLong(&ptr, &length) && *(ptr++) == ':') {
+				hex2mem(ptr, (char *)addr, length, 1);
+				if (kgdb_memerr)
+					strcpy(remcomOutBuffer, "E09");
+				else
+					strcpy(remcomOutBuffer, "OK");
+				ptr = 0;
+			}
+			if (ptr) {
+				strcpy(remcomOutBuffer, "E02");
+			}
+			break;
+		/* GDB has told us it is detaching.  So we'll remove all of
+		 * our breakpoints and get back to 'normal'. */
+		case 'D':
+			strcpy(remcomOutBuffer, "OK");
+			putpacket(remcomOutBuffer);
+			/* fall through. */
+		/* GDB is telling us to 'kill' the running process.  We'll
+		 * just stop debugging. */
+		case 'k':
+			remove_all_break();
+			kgdb_connected = 0;
+			goto kgdb_exit;
+		/* query */
+		case 'q':
+			switch (remcomInBuffer[1]) {
+			case 's':
+			case 'f':
+				if (memcmp(remcomInBuffer+2, "ThreadInfo",10))
+				{
+					strcpy(remcomOutBuffer, "E04");
+					break;
+				}
+				if (remcomInBuffer[1] == 'f') {
+					threadid = 1;
+				}
+				remcomOutBuffer[0] = 'm';
+				ptr = remcomOutBuffer + 1;
+				for (i = 0; i < 32 && threadid < pid_max + numshadowth;
+						threadid++) {
+					thread = getthread(linux_regs, threadid);
+					if (thread) {
+						int_to_threadref(&thref,
+								threadid);
+						pack_threadid(ptr, &thref);
+						ptr += 16;
+						*(ptr++) = ',';
+						i++;
+					}
+				}
+				break;
+
+			case 'C':
+				/* Current thread id */
+				strcpy(remcomOutBuffer, "QC");
+
+				threadid = shadow_pid(current->pid);
+				
+				int_to_threadref(&thref, threadid);
+				pack_threadid(remcomOutBuffer + 2, &thref);
+				break;
+
+			case 'E':
+				/* Print exception info */
+				kgdb_printexceptioninfo(exVector, err_code,
+						remcomOutBuffer);
+				break;
+			case 'T':
+				if (memcmp(remcomInBuffer+1, "ThreadExtraInfo,",16))
+				{
+					strcpy(remcomOutBuffer, "E05");
+					break;
+				}
+				threadid = 0;
+				ptr = remcomInBuffer+17;
+				kgdb_hexToLong(&ptr, &threadid);
+				if (!getthread(linux_regs, threadid)) {
+					sprintf(tmpstr, "invalid pid %d",
+							(int) threadid);
+					kgdb_mem2hex(tmpstr, remcomOutBuffer,
+							strlen(tmpstr), 0);
+					break;
+				}
+				if (threadid < pid_max) {
+					kgdb_mem2hex(getthread(linux_regs, threadid)->comm,
+							remcomOutBuffer, 16, 0);
+				} else if (threadid >= pid_max +
+						num_online_cpus()) {
+					kgdb_shadowinfo(linux_regs,
+						remcomOutBuffer,
+						threadid - pid_max -
+						num_online_cpus());
+				} else {
+					sprintf(tmpstr, "Shadow task %d for pid 0",
+							(int)(threadid -
+							      pid_max));
+					kgdb_mem2hex(tmpstr, remcomOutBuffer,
+							strlen(tmpstr), 0);
+				}
+				break;
+			}
+			break;
+
+			/* task related */
+		case 'H':
+			switch (remcomInBuffer[1]) {
+			case 'g':
+				ptr = &remcomInBuffer[2];
+				kgdb_hexToLong(&ptr, &threadid);
+				thread = getthread(linux_regs, threadid);
+				if (!thread && threadid > 0) {
+					remcomOutBuffer[0] = 'E';
+					break;
+				}
+				kgdb_usethread = thread;
+				kgdb_usethreadid = threadid;
+				strcpy(remcomOutBuffer, "OK");
+				break;
+
+			case 'c':
+				ptr = &remcomInBuffer[2];
+				kgdb_hexToLong(&ptr, &threadid);
+				if (!threadid) {
+					kgdb_contthread = 0;
+				} else {
+					thread = getthread(linux_regs, threadid);
+					if (!thread && threadid > 0) {
+						remcomOutBuffer[0] = 'E';
+						break;
+					}
+					kgdb_contthread = thread;
+				}
+				strcpy(remcomOutBuffer, "OK");
+				break;
+			}
+			break;
+
+			/* Query thread status */
+		case 'T':
+			ptr = &remcomInBuffer[1];
+			kgdb_hexToLong(&ptr, &threadid);
+			thread = getthread(linux_regs, threadid);
+			if (thread)
+				strcpy(remcomOutBuffer, "OK");
+			else
+				remcomOutBuffer[0] = 'E';
+			break;
+		case 'z':
+		case 'Z':
+			ptr = &remcomInBuffer[2];
+			if (*(ptr++) != ',') {
+				strcpy(remcomOutBuffer, "E07");
+				break;
+			}
+			kgdb_hexToLong(&ptr, &addr);
+			
+			bpt_type = remcomInBuffer[1];
+			if (bpt_type != bp_breakpoint) {
+				if (bpt_type == bp_hardware_breakpoint && 
+				    !(kgdb_ops->flags & KGDB_HW_BREAKPOINT))
+					break;
+
+				/* if set_break is not defined, then
+				 * remove_break does not matter
+				 */
+				if(!(kgdb_ops->flags & KGDB_HW_BREAKPOINT))
+					break;
+			}
+			
+			if (remcomInBuffer[0] == 'Z') {
+				if (bpt_type == bp_breakpoint)
+					ret = set_break(addr);
+				else
+					ret = kgdb_arch_set_break(addr,
+							bpt_type);
+			}
+			else {
+				if (bpt_type == bp_breakpoint)
+					ret = remove_break(addr);
+				else
+					ret = kgdb_arch_remove_break(addr,
+							bpt_type);
+			}
+			
+			if (ret == 0)
+				strcpy(remcomOutBuffer, "OK");
+			else
+				strcpy(remcomOutBuffer, "E08");
+			
+			break;
+
+		default:
+			if (kgdb_arch_handle_exception(exVector, signo,
+						err_code, remcomInBuffer,
+						remcomOutBuffer,
+						linux_regs) >= 0)
+				/* Get out of here. */
+				goto kgdb_exit;
+		}		/* switch */
+#if KGDB_DEBUG
+		bust_spinlocks(1);
+		printk("Response to GDB: %s\n", remcomOutBuffer);
+		bust_spinlocks(0);
+#endif
+
+		/* reply to the request */
+		putpacket(remcomOutBuffer);
+	}
+
+kgdb_exit:
+	procindebug[smp_processor_id()] = 0;	
+	
+	for (i = 0; i < num_online_cpus(); i++) {
+		spin_unlock(&slavecpulocks[i]);
+	}
+	/* Wait till all the processors have quit
+	 * from the debugger 
+	 */
+	for (i = 0; i < num_online_cpus(); i++) { 
+		while (procindebug[i]) {
+			int j = 10; /* an arbitrary number */
+
+			while (--j) {
+				asm volatile ("nop" : : : "memory");
+			}
+			barrier();
+		}
+	}
+
+	/* Free debugger_active */
+	atomic_set(&debugger_active, 0);
+	local_irq_restore(flags);
+
+	return ret;
+}
+
+/*
+ * GDB places a breakpoint at this function to know dynamically
+ * loaded objects. It's not defined static so that only one instance with this
+ * name exists in the kernel.
+ */
+
+int module_event(struct notifier_block * self, unsigned long val, void * data)
+{
+	return 0;
+}
+
+/* this function is used to set up exception handlers for tracing and
+   breakpoints */
+static void set_debug_traps(void)
+{
+	int i;
+	
+	for (i = 0; i < KGDB_MAX_NO_CPUS; i++) 
+		spin_lock_init(&slavecpulocks[i]);
+
+	/* Free debugger_active */
+	atomic_set(&debugger_active, 0);
+
+	for (i = 0; i < MAX_BREAKPOINTS; i++) 
+		kgdb_break[i].state = bp_disabled;
+
+	linux_debug_hook = kgdb_handle_exception;
+
+	/* We can't do much if this fails */
+	register_module_notifier(&kgdb_module_load_nb);
+
+	kgdb_initialized = 1;
+
+	atomic_set(&kgdb_setting_breakpoint, 0);
+}
+
+/* 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 breakpoint(void)
+{
+	if (!kgdb_initialized)
+		set_debug_traps();
+
+	atomic_set(&kgdb_setting_breakpoint, 1);
+	wmb();
+	BREAKPOINT();
+	wmb();
+	atomic_set(&kgdb_setting_breakpoint, 0);
+}
+
+void kgdb_nmihook(int cpu, void *regs)
+{
+#ifdef CONFIG_SMP
+	if (!procindebug[cpu] && atomic_read(&debugger_active) != (cpu + 1)) {
+		kgdb_wait((struct pt_regs *)regs);
+	}
+#endif
+}
+
+void kgdb_entry(void)
+{
+	if (kgdb_initialized) {
+		/* KGDB was initialized */
+		return;
+	}
+	if (!kgdb_enter) {
+		return;
+	}
+
+	/* Let the arch do any initalization it needs to, including
+	 * pointing to a suitable early output device. */
+	kgdb_arch_init();
+
+	if (!kgdb_serial) {
+		printk("KGDB: no gdb interface available.\n"
+		       "kgdb can't be enabled\n");
+		return;
+	}
+	if (kgdb_serial->hook()) {
+		/* KGDB interface isn't ready yet */
+		return;
+	}
+	
+	/*
+	 * Call GDB routine to setup the exception vectors for the debugger
+	 */
+	set_debug_traps();
+
+	/*
+	 * Call the breakpoint() routine in GDB to start the debugging
+	 * session
+	 */
+	printk(KERN_CRIT "Waiting for connection from remote gdb... ");
+	breakpoint() ;
+	printk("Connected.\n");
+}
+
+/*
+ * Sometimes we need to schedule a breakpoint because we can't break
+ * right where we are.
+ */
+static int kgdb_need_breakpoint[NR_CPUS];
+
+void kgdb_schedule_breakpoint(void)
+{
+	kgdb_need_breakpoint[smp_processor_id()] = 1;
+}
+
+void kgdb_process_breakpoint(void)
+{
+	/*
+	 * Handle a breakpoint queued from inside network driver code
+         * to avoid reentrancy issues
+	 */
+	if (kgdb_need_breakpoint[smp_processor_id()]) {
+		kgdb_need_breakpoint[smp_processor_id()] = 0;
+		breakpoint();
+	}
+}
+
+#ifdef CONFIG_KGDB_CONSOLE
+char kgdbconbuf[BUFMAX];
+
+void kgdb_console_write(struct console *co, const char *s, unsigned count)
+{
+	int i;
+	int wcount;
+	char *bufptr;
+	unsigned long flags;
+
+	if (!kgdb_connected) {
+		return;
+	}
+	local_irq_save(flags);
+
+	kgdbconbuf[0] = 'O';
+	bufptr = kgdbconbuf + 1;
+	while (count > 0) {
+		if ((count << 1) > (BUFMAX - 2)) {
+			wcount = (BUFMAX - 2) >> 1;
+		} else {
+			wcount = count;
+		}
+		count -= wcount;
+		for (i = 0; i < wcount; i++) {
+			bufptr = pack_hex_byte(bufptr, s[i]);
+		}
+		*bufptr = '\0';
+		s += wcount;
+
+		putpacket(kgdbconbuf);
+
+	}
+	local_irq_restore(flags);
+}
+
+/* Always fail so that kgdb console doesn't become the default console */
+static int __init kgdb_console_setup(struct console *co, char *options)
+{
+	return -1;
+}
+
+static struct console kgdbcons = {
+	.name = "kgdb",
+	.write = kgdb_console_write,
+	.setup = kgdb_console_setup,
+	.flags = CON_PRINTBUFFER | CON_ENABLED,
+	.index = -1,
+};
+
+static int __init kgdb_console_init(void)
+{
+	register_console(&kgdbcons);
+	return 0;
+}
+console_initcall(kgdb_console_init);
+#endif
+
+EXPORT_SYMBOL(breakpoint);
+#ifdef CONFIG_KGDB_THREAD
+EXPORT_SYMBOL(kern_schedule);
+#endif
+
+static int __init opt_kgdb_enter(char *str)
+{
+	kgdb_enter = 1;
+	return 1;
+}
+
+static int __init opt_gdb(char *str)
+{
+	kgdb_enter = 1;
+	return 1;
+}
+
+/*
+ * These options have been deprecated and are present only to maintain
+ * compatibility with kgdb for 2.4 and earlier kernels.
+ */
+#ifdef CONFIG_KGDB_8250
+extern int kgdb8250_baud;
+extern int kgdb8250_ttyS;
+static int __init opt_gdbttyS(char *str)
+{
+	kgdb8250_ttyS = simple_strtoul(str, NULL, 10);
+	return 1;
+}
+static int __init opt_gdbbaud(char *str)
+{
+	kgdb8250_baud = simple_strtoul(str, NULL, 10);
+	return 1;
+}
+#endif
+
+/*
+ *
+ * Sequence of following lines has to be maintained because gdb option is a
+ * prefix of the other two options
+ */
+
+#ifdef CONFIG_KGDB_8250
+__setup("gdbttyS=", opt_gdbttyS);
+__setup("gdbbaud=", opt_gdbbaud);
+#endif
+__setup("gdb", opt_gdb);
+__setup("kgdbwait", opt_kgdb_enter);
--- a/kernel/module.c	Wed Feb 11 15:41:28 2004
+++ b/kernel/module.c	Wed Feb 11 15:41:28 2004
@@ -744,6 +744,11 @@
 	/* Stop the machine so refcounts can't move and disable module. */
 	ret = try_stop_module(mod, flags, &forced);
 
+	down(&notify_mutex);
+	notifier_call_chain(&module_notify_list, MODULE_STATE_GOING,
+				mod);
+	up(&notify_mutex);
+
 	/* Never wait if forced. */
 	if (!forced && module_refcount(mod) != 0)
 		wait_for_zero_refcount(mod);
@@ -1775,7 +1780,12 @@
 	if (ret < 0) {
 		/* Init routine failed: abort.  Try to protect us from
                    buggy refcounters. */
+
 		mod->state = MODULE_STATE_GOING;
+		down(&notify_mutex);
+		notifier_call_chain(&module_notify_list, MODULE_STATE_GOING,
+					mod);
+		up(&notify_mutex);
 		synchronize_kernel();
 		if (mod->unsafe)
 			printk(KERN_ERR "%s: module is now stuck!\n",
--- a/kernel/sched.c	Wed Feb 11 15:41:28 2004
+++ b/kernel/sched.c	Wed Feb 11 15:41:28 2004
@@ -38,6 +38,7 @@
 #include <linux/cpu.h>
 #include <linux/percpu.h>
 #include <linux/kthread.h>
+#include <linux/debugger.h>
 
 #ifdef CONFIG_NUMA
 #define cpu_to_node_mask(cpu) node_to_cpumask(cpu_to_node(cpu))
@@ -1904,7 +1905,7 @@
 /*
  * schedule() is the main scheduler function.
  */
-asmlinkage void schedule(void)
+asmlinkage void do_schedule(void)
 {
 	long *switch_count;
 	task_t *prev, *next;
@@ -2076,6 +2077,23 @@
 
 EXPORT_SYMBOL(default_wake_function);
 
+asmlinkage void user_schedule(void)
+{
+#ifdef CONFIG_KGDB_THREAD
+	current->thread.debuggerinfo = NULL;
+#endif
+	do_schedule();
+}
+
+#ifdef CONFIG_KGDB_THREAD
+asmlinkage void kern_do_schedule(struct pt_regs regs)
+{
+	current->thread.debuggerinfo = &regs;
+	do_schedule();
+	current->thread.debuggerinfo = NULL;
+}
+#endif
+
 /*
  * The core wakeup function.  Non-exclusive wakeups (nr_exclusive == 0) just
  * wake everything up.  If it's an exclusive wakeup (nr_exclusive == small +ve
@@ -3542,6 +3560,8 @@
 #if defined(in_atomic)
 	static unsigned long prev_jiffy;	/* ratelimiting */
 
+	if (atomic_read(&debugger_active))
+		return;
 	if ((in_atomic() || irqs_disabled()) && system_running) {
 		if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
 			return;

-- 
Tom Rini
http://gate.crashing.org/~trini/

^ permalink raw reply	[flat|nested] 9+ messages in thread

end of thread, other threads:[~2004-02-25 17:50 UTC | newest]

Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2004-02-17 22:02 [PATCH][1/6] A different KGDB stub Tom Rini
2004-02-17 23:50 ` Andrew Morton
2004-02-18  0:03   ` Tom Rini
2004-02-18  0:33     ` Andrew Morton
2004-02-18  0:39       ` Tom Rini
2004-02-25 17:50       ` Tom Rini
2004-02-18 19:36 ` Pavel Machek
2004-02-18 20:23   ` Tom Rini
  -- strict thread matches above, loose matches on Subject: below --
2004-02-12  0:02 Tom Rini

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