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Message-ID: <20080210071331.GC3851@elte.hu>
Date: Sun, 10 Feb 2008 08:13:31 +0100
From: Ingo Molnar <mingo@...e.hu>
To: linux-kernel@...r.kernel.org
Cc: Linus Torvalds <torvalds@...ux-foundation.org>,
Andrew Morton <akpm@....com.au>,
Thomas Gleixner <tglx@...utronix.de>,
Jason Wessel <jason.wessel@...driver.com>
Subject: [3/6] kgdb: core
From: Jason Wessel <jason.wessel@...driver.com>
kgdb core code. Handles the protocol and the arch details.
[ mingo@...e.hu: heavily modified, simplified and cleaned up. ]
Signed-off-by: Ingo Molnar <mingo@...e.hu>
Reviewed-by: Thomas Gleixner <tglx@...utronix.de>
---
include/asm-generic/kgdb.h | 93 ++
include/linux/kgdb.h | 264 +++++
kernel/Makefile | 1
kernel/kgdb.c | 2020 +++++++++++++++++++++++++++++++++++++++++++++
lib/Kconfig.debug | 2
lib/Kconfig.kgdb | 37
6 files changed, 2417 insertions(+)
Index: linux-kgdb.q/include/asm-generic/kgdb.h
===================================================================
--- /dev/null
+++ linux-kgdb.q/include/asm-generic/kgdb.h
@@ -0,0 +1,93 @@
+/*
+ * include/asm-generic/kgdb.h
+ *
+ * This provides the assembly level information so that KGDB can provide
+ * a GDB that has been patched with enough information to know to stop
+ * trying to unwind the function.
+ *
+ * Author: Tom Rini <trini@...nel.crashing.org>
+ *
+ * 2005 (c) MontaVista Software, Inc.
+ * 2006 (c) Embedded Alley Solutions, Inc.
+ *
+ * This file is licensed under the terms of the GNU General Public License
+ * version 2. This program is licensed "as is" without any warranty of any
+ * kind, whether express or implied.
+ */
+
+#ifndef __ASM_GENERIC_KGDB_H__
+#define __ASM_GENERIC_KGDB_H__
+
+struct pt_regs;
+
+/**
+ * kgdb_skipexception - Bail of of KGDB when we've been triggered.
+ * @exception: Exception vector number
+ * @regs: Current &struct pt_regs.
+ *
+ * On some architectures we need to skip a breakpoint exception when
+ * it occurs after a breakpoint has been removed.
+ */
+int kgdb_skipexception(int exception, struct pt_regs *regs);
+
+/**
+ * kgdb_post_master_code - Save error vector/code numbers.
+ * @regs: Original pt_regs.
+ * @e_vector: Original error vector.
+ * @err_code: Original error code.
+ *
+ * This is needed on architectures which support SMP and KGDB.
+ * This function is called after all the slave cpus have been put
+ * to a know spin state and the master CPU has control over KGDB.
+ */
+extern void kgdb_post_master_code(struct pt_regs *regs, int e_vector,
+ int err_code);
+
+/**
+ * kgdb_disable_hw_debug - Disable hardware debugging while we in kgdb.
+ * @regs: Current &struct pt_regs.
+ *
+ * This function will be called if the particular architecture must
+ * disable hardware debugging while it is processing gdb packets or
+ * handling exception.
+ */
+extern void kgdb_disable_hw_debug(struct pt_regs *regs);
+
+#ifdef CONFIG_KGDB_ARCH_HAS_SHADOW_INFO
+/**
+ * kgdb_shadowinfo - Get shadowed information on @threadid.
+ * @regs: The &struct pt_regs of the current process.
+ * @buffer: A buffer of %BUFMAX size.
+ * @threadid: The thread id of the shadowed process to get information on.
+ */
+extern void kgdb_shadowinfo(struct pt_regs *regs, char *buffer,
+ unsigned threadid);
+
+/**
+ * kgdb_get_shadow_thread - Get the shadowed &task_struct of @threadid.
+ * @regs: The &struct pt_regs of the current thread.
+ * @threadid: The thread id of the shadowed process to get information on.
+ *
+ * RETURN:
+ * This returns a pointer to the &struct task_struct of the shadowed
+ * thread, @threadid.
+ */
+extern struct task_struct *kgdb_get_shadow_thread(struct pt_regs *regs,
+ int threadid);
+
+/**
+ * kgdb_shadow_regs - Return the shadowed registers of @threadid.
+ * @regs: The &struct pt_regs of the current thread.
+ * @threadid: The thread id we want the &struct pt_regs for.
+ *
+ * RETURN:
+ * The a pointer to the &struct pt_regs of the shadowed thread @threadid.
+ */
+extern struct pt_regs *kgdb_shadow_regs(struct pt_regs *regs, int threadid);
+#else
+#define kgdb_shadowinfo(regs, buf, threadid) do { } while (0)
+#define kgdb_get_shadow_thread(regs, threadid) NULL
+#define kgdb_shadow_regs(regs, threadid) NULL
+#endif
+
+#endif /* __ASM_GENERIC_KGDB_H__ */
Index: linux-kgdb.q/include/linux/kgdb.h
===================================================================
--- /dev/null
+++ linux-kgdb.q/include/linux/kgdb.h
@@ -0,0 +1,264 @@
+/*
+ * include/linux/kgdb.h
+ *
+ * This provides the callbacks and functions that KGDB needs to share between
+ * the core, I/O and arch-specific portions.
+ *
+ * Author: Amit Kale <amitkale@...syssoft.com> and
+ * Tom Rini <trini@...nel.crashing.org>
+ *
+ * 2001-2004 (c) Amit S. Kale and 2003-2005 (c) MontaVista Software, Inc.
+ * This file is licensed under the terms of the GNU General Public License
+ * version 2. This program is licensed "as is" without any warranty of any
+ * kind, whether express or implied.
+ */
+#ifndef _KGDB_H_
+#define _KGDB_H_
+
+#include <asm/atomic.h>
+
+#ifdef CONFIG_KGDB
+#include <asm/kgdb.h>
+#include <linux/serial_8250.h>
+#include <linux/linkage.h>
+#include <linux/init.h>
+
+struct tasklet_struct;
+struct pt_regs;
+struct task_struct;
+struct uart_port;
+
+/* To enter the debugger explicitly. */
+void kgdb_breakpoint(void);
+
+extern int kgdb_connected;
+extern int kgdb_may_fault;
+
+extern atomic_t kgdb_setting_breakpoint;
+extern atomic_t cpu_doing_single_step;
+
+extern struct task_struct *kgdb_usethread;
+extern struct task_struct *kgdb_contthread;
+
+enum kgdb_bptype {
+ BP_BREAKPOINT = 0,
+ BP_HARDWARE_BREAKPOINT,
+ BP_WRITE_WATCHPOINT,
+ BP_READ_WATCHPOINT,
+ BP_ACCESS_WATCHPOINT
+};
+
+enum kgdb_bpstate {
+ BP_UNDEFINED = 0,
+ BP_REMOVED,
+ BP_SET,
+ BP_ACTIVE
+};
+
+struct kgdb_bkpt {
+ unsigned long bpt_addr;
+ unsigned char saved_instr[BREAK_INSTR_SIZE];
+ enum kgdb_bptype type;
+ enum kgdb_bpstate state;
+};
+
+/* The maximum number of KGDB I/O modules that can be loaded */
+#define KGDB_MAX_IO_HANDLERS 3
+
+#ifndef KGDB_MAX_BREAKPOINTS
+# define KGDB_MAX_BREAKPOINTS 1000
+#endif
+
+#define KGDB_HW_BREAKPOINT 1
+
+/*
+ * Functions each KGDB-supporting architecture must provide:
+ */
+
+/**
+ * kgdb_arch_init - Perform any architecture specific initalization.
+ *
+ * This function will handle the initalization of any architecture
+ * specific callbacks.
+ */
+int kgdb_arch_init(void);
+
+/**
+ * kgdb_arch_uninit - Perform any architecture specific uninitalization.
+ *
+ * This function will handle the uninitalization of any architecture
+ * specific callbacks, for dynamic registration and unregistration.
+ */
+void kgdb_arch_uninit(void);
+
+/**
+ * pt_regs_to_gdb_regs - Convert ptrace regs to GDB regs
+ * @gdb_regs: A pointer to hold the registers in the order GDB wants.
+ * @regs: The &struct pt_regs of the current process.
+ *
+ * Convert the pt_regs in @regs into the format for registers that
+ * GDB expects, stored in @gdb_regs.
+ */
+void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs);
+
+/**
+ * sleeping_thread_to_gdb_regs - Convert ptrace regs to GDB regs
+ * @gdb_regs: A pointer to hold the registers in the order GDB wants.
+ * @p: The &struct task_struct of the desired process.
+ *
+ * Convert the register values of the sleeping process in @p to
+ * the format that GDB expects.
+ * This function is called when kgdb does not have access to the
+ * &struct pt_regs and therefore it should fill the gdb registers
+ * @gdb_regs with what has been saved in &struct thread_struct
+ * thread field during switch_to.
+ */
+void
+sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p);
+
+/**
+ * gdb_regs_to_pt_regs - Convert GDB regs to ptrace regs.
+ * @gdb_regs: A pointer to hold the registers we've received from GDB.
+ * @regs: A pointer to a &struct pt_regs to hold these values in.
+ *
+ * Convert the GDB regs in @gdb_regs into the pt_regs, and store them
+ * in @regs.
+ */
+void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs);
+
+/**
+ * kgdb_arch_handle_exception - Handle architecture specific GDB packets.
+ * @vector: The error vector of the exception that happened.
+ * @signo: The signal number of the exception that happened.
+ * @err_code: The error code of the exception that happened.
+ * @remcom_in_buffer: The buffer of the packet we have read.
+ * @remcom_out_buffer: The buffer of %BUFMAX bytes to write a packet into.
+ * @regs: The &struct pt_regs of the current process.
+ *
+ * This function MUST handle the 'c' and 's' command packets,
+ * as well packets to set / remove a hardware breakpoint, if used.
+ * If there are additional packets which the hardware needs to handle,
+ * they are handled here. The code should return -1 if it wants to
+ * process more packets, and a %0 or %1 if it wants to exit from the
+ * kgdb callback.
+ */
+int kgdb_arch_handle_exception(int vector, int signo, int err_code,
+ char *remcom_in_buffer,
+ char *remcom_out_buffer,
+ struct pt_regs *regs);
+
+/**
+ * kgdb_roundup_cpus - Get other CPUs into a holding pattern
+ * @flags: Current IRQ state
+ *
+ * On SMP systems, we need to get the attention of the other CPUs
+ * and get them be in a known state. This should do what is needed
+ * to get the other CPUs to call kgdb_wait(). Note that on some arches,
+ * the NMI approach is not used for rounding up all the CPUs. For example,
+ * in case of MIPS, smp_call_function() is used to roundup CPUs. In
+ * this case, we have to make sure that interrupts are enabled before
+ * calling smp_call_function(). The argument to this function is
+ * the flags that will be used when restoring the interrupts. There is
+ * local_irq_save() call before kgdb_roundup_cpus().
+ *
+ * On non-SMP systems, this is not called.
+ */
+void kgdb_roundup_cpus(unsigned long flags);
+
+/* Optional functions. */
+int kgdb_validate_break_address(unsigned long addr);
+int kgdb_arch_set_breakpoint(unsigned long addr, char *saved_instr);
+int kgdb_arch_remove_breakpoint(unsigned long addr, char *bundle);
+
+/**
+ * struct kgdb_arch - Describe architecture specific values.
+ * @gdb_bpt_instr: The instruction to trigger a breakpoint.
+ * @flags: Flags for the breakpoint, currently just %KGDB_HW_BREAKPOINT.
+ * @shadowth: A value of %1 indicates we shadow information on processes.
+ * @set_breakpoint: Allow an architecture to specify how to set a software
+ * breakpoint.
+ * @remove_breakpoint: Allow an architecture to specify how to remove a
+ * software breakpoint.
+ * @set_hw_breakpoint: Allow an architecture to specify how to set a hardware
+ * breakpoint.
+ * @remove_hw_breakpoint: Allow an architecture to specify how to remove a
+ * hardware breakpoint.
+ * @remove_all_hw_break: Allow an architecture to specify how to remove all
+ * hardware breakpoints.
+ * @correct_hw_break: Allow an architecture to specify how to correct the
+ * hardware debug registers.
+ *
+ * The @shadowth flag is an option to shadow information not retrievable by
+ * gdb otherwise. This is deprecated in favor of a binutils which supports
+ * CFI macros.
+ */
+struct kgdb_arch {
+ unsigned char gdb_bpt_instr[BREAK_INSTR_SIZE];
+ unsigned long flags;
+ unsigned shadowth;
+
+ int (*set_breakpoint)(unsigned long, char *);
+ int (*remove_breakpoint)(unsigned long, char *);
+ int (*set_hw_breakpoint)(unsigned long, int, enum kgdb_bptype);
+ int (*remove_hw_breakpoint)(unsigned long, int, enum kgdb_bptype);
+ void (*remove_all_hw_break)(void);
+ void (*correct_hw_break)(void);
+};
+
+/**
+ * struct kgdb_io - Describe the interface for an I/O driver to talk with KGDB.
+ * @name: Name of the I/O driver.
+ * @read_char: Pointer to a function that will return one char.
+ * @write_char: Pointer to a function that will write one char.
+ * @flush: Pointer to a function that will flush any pending writes.
+ * @init: Pointer to a function that will initialize the device.
+ * @late_init: Pointer to a function that will do any setup that has
+ * other dependencies.
+ * @pre_exception: Pointer to a function that will do any prep work for
+ * the I/O driver.
+ * @post_exception: Pointer to a function that will do any cleanup work
+ * for the I/O driver.
+ *
+ * The @init and @late_init function pointers allow for an I/O driver
+ * such as a serial driver to fully initialize the port with @init and
+ * be called very early, yet safely call request_irq() later in the boot
+ * sequence.
+ *
+ * @init is allowed to return a non-0 return value to indicate failure.
+ * If this is called early on, then KGDB will try again when it would call
+ * @late_init. If it has failed later in boot as well, the user will be
+ * notified.
+ */
+struct kgdb_io {
+ const char *name;
+ int (*read_char) (void);
+ void (*write_char) (u8);
+ void (*flush) (void);
+ int (*init) (void);
+ void (*pre_exception) (void);
+ void (*post_exception) (void);
+};
+
+extern struct kgdb_arch arch_kgdb_ops;
+
+int kgdb_register_io_module(struct kgdb_io *local_kgdb_io_ops);
+void kgdb_unregister_io_module(struct kgdb_io *local_kgdb_io_ops);
+
+int kgdb_hex2long(char **ptr, long *long_val);
+char *kgdb_mem2hex(char *mem, char *buf, int count);
+char *kgdb_hex2mem(char *buf, char *mem, int count);
+
+int kgdb_isremovedbreak(unsigned long addr);
+
+int kgdb_handle_exception(int ex_vector, int signo, int err_code,
+ struct pt_regs *regs);
+int kgdb_nmicallback(int cpu, void *regs);
+
+extern int debugger_step;
+extern atomic_t debugger_active;
+
+#else /* !CONFIG_KGDB */
+static const atomic_t debugger_active = ATOMIC_INIT(0);
+#endif /* !CONFIG_KGDB */
+
+#endif /* _KGDB_H_ */
Index: linux-kgdb.q/kernel/Makefile
===================================================================
--- linux-kgdb.q.orig/kernel/Makefile
+++ linux-kgdb.q/kernel/Makefile
@@ -53,6 +53,7 @@ obj-$(CONFIG_AUDIT) += audit.o auditfilt
obj-$(CONFIG_AUDITSYSCALL) += auditsc.o
obj-$(CONFIG_AUDIT_TREE) += audit_tree.o
obj-$(CONFIG_KPROBES) += kprobes.o
+obj-$(CONFIG_KGDB) += kgdb.o
obj-$(CONFIG_DETECT_SOFTLOCKUP) += softlockup.o
obj-$(CONFIG_GENERIC_HARDIRQS) += irq/
obj-$(CONFIG_SECCOMP) += seccomp.o
Index: linux-kgdb.q/kernel/kgdb.c
===================================================================
--- /dev/null
+++ linux-kgdb.q/kernel/kgdb.c
@@ -0,0 +1,2020 @@
+/*
+ * kernel/kgdb.c
+ *
+ * Maintainer: Jason Wessel <jason.wessel@...driver.com>
+ *
+ * Copyright (C) 2000-2001 VERITAS Software Corporation.
+ * Copyright (C) 2002-2004 Timesys Corporation
+ * Copyright (C) 2003-2004 Amit S. Kale <amitkale@...syssoft.com>
+ * Copyright (C) 2004 Pavel Machek <pavel@...e.cz>
+ * Copyright (C) 2004-2006 Tom Rini <trini@...nel.crashing.org>
+ * Copyright (C) 2004-2006 LinSysSoft Technologies Pvt. Ltd.
+ * Copyright (C) 2005-2008 Wind River Systems, Inc.
+ * Copyright (C) 2007 MontaVista Software, Inc.
+ * Copyright (C) 2008 Red Hat, Inc., Ingo Molnar <mingo@...hat.com>
+ *
+ * Contributors at various stages not listed above:
+ * Jason Wessel ( jason.wessel@...driver.com )
+ * George Anzinger <george@...sta.com>
+ * Anurekh Saxena (anurekh.saxena@...esys.com)
+ * Lake Stevens Instrument Division (Glenn Engel)
+ * Jim Kingdon, Cygnus Support.
+ *
+ * Original KGDB stub: David Grothe <dave@...m.com>,
+ * Tigran Aivazian <tigran@....com>
+ *
+ * This file is licensed under the terms of the GNU General Public License
+ * version 2. This program is licensed "as is" without any warranty of any
+ * kind, whether express or implied.
+ */
+#include <linux/pid_namespace.h>
+#include <linux/interrupt.h>
+#include <linux/notifier.h>
+#include <linux/spinlock.h>
+#include <linux/console.h>
+#include <linux/threads.h>
+#include <linux/uaccess.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/ptrace.h>
+#include <linux/reboot.h>
+#include <linux/string.h>
+#include <linux/delay.h>
+#include <linux/sched.h>
+#include <linux/sysrq.h>
+#include <linux/init.h>
+#include <linux/kgdb.h>
+#include <linux/pid.h>
+#include <linux/smp.h>
+#include <linux/mm.h>
+
+#include <asm/cacheflush.h>
+#include <asm/byteorder.h>
+#include <asm/atomic.h>
+#include <asm/system.h>
+
+static int kgdb_break_asap;
+
+struct kgdb_state {
+ int all_cpus_synced;
+ int ex_vector;
+ int signo;
+ int err_code;
+ int cpu;
+ int pass_exception;
+ long threadid;
+ long kgdb_usethreadid;
+ struct pt_regs *linux_regs;
+};
+
+struct debuggerinfo_struct {
+ void *debuggerinfo;
+ struct task_struct *task;
+} kgdb_info[NR_CPUS];
+
+/*
+ * Could we be about to try and access a bad memory location?
+ * If so we also need to flag this has happened.
+ */
+int kgdb_may_fault;
+
+/* Is a host GDB connected to us? */
+int kgdb_connected;
+EXPORT_SYMBOL_GPL(kgdb_connected);
+
+/* All the KGDB handlers are installed */
+int kgdb_io_module_registered;
+
+/* Guard for recursive entry */
+static int exception_level;
+
+static struct kgdb_io *kgdb_io_ops;
+static DEFINE_SPINLOCK(kgdb_registration_lock);
+
+/*
+ * Holds information about breakpoints in a kernel. These breakpoints are
+ * added and removed by gdb.
+ */
+struct kgdb_bkpt kgdb_break[KGDB_MAX_BREAKPOINTS] = {
+ [0 ... KGDB_MAX_BREAKPOINTS-1] = { .state = BP_UNDEFINED }
+};
+
+/*
+ * KGDB locking is really nasty at places - but we really can only
+ * do sane debugging if all processors are in a controlled state.
+ *
+ * So we go through painful cycles of wait and see, with every
+ * CPU having a lock:
+ */
+
+/* How many times to count all of the waiting CPUs */
+#define ROUNDUP_WAIT 640000 /* Arbitrary, increase if needed. */
+#define BUF_THREAD_ID_SIZE 16
+
+static spinlock_t slave_cpu_locks[NR_CPUS] = {
+ [0 ... NR_CPUS-1] = __SPIN_LOCK_UNLOCKED(slave_cpu_locks)
+};
+static atomic_t cpu_in_kgdb[NR_CPUS];
+atomic_t kgdb_setting_breakpoint;
+
+struct task_struct *kgdb_usethread;
+struct task_struct *kgdb_contthread;
+
+int debugger_step;
+static atomic_t kgdb_sync = ATOMIC_INIT(-1);
+atomic_t debugger_active;
+
+/* Our I/O buffers. */
+static char remcom_in_buffer[BUFMAX];
+static char remcom_out_buffer[BUFMAX];
+
+/* Storage for the registers, in GDB format. */
+static unsigned long gdb_regs[(NUMREGBYTES +
+ sizeof(unsigned long) - 1) /
+ sizeof(unsigned long)];
+
+/* to keep track of the CPU which is doing the single stepping*/
+atomic_t cpu_doing_single_step = ATOMIC_INIT(-1);
+
+static int
+kgdb_notify_reboot(struct notifier_block *this, unsigned long code, void *x);
+
+/* reboot notifier block */
+static struct notifier_block kgdb_reboot_notifier = {
+ .notifier_call = kgdb_notify_reboot,
+ .next = NULL,
+ .priority = INT_MAX,
+};
+
+/*
+ * Finally, some KGDB code :-)
+ */
+
+static char *kgdb_get_mem(char *addr, unsigned char *buf, int count)
+{
+ while (count) {
+ if ((unsigned long)addr < TASK_SIZE) {
+ kgdb_may_fault = 0;
+ return ERR_PTR(-EINVAL);
+ }
+ if (probe_kernel_address(addr, *buf)) {
+ kgdb_may_fault = 0;
+ return ERR_PTR(-EINVAL);
+ }
+ buf++;
+ addr++;
+ count--;
+ }
+ kgdb_may_fault = 0;
+
+ return NULL;
+}
+
+static char *kgdb_set_mem(char *addr, unsigned char *buf, int count)
+{
+ while (count) {
+ if ((unsigned long)addr < TASK_SIZE) {
+ kgdb_may_fault = 0;
+ return ERR_PTR(-EINVAL);
+ }
+ if (probe_kernel_write(addr, *buf)) {
+ kgdb_may_fault = 0;
+ return ERR_PTR(-EINVAL);
+ }
+ buf++;
+ addr++;
+ count--;
+ }
+ kgdb_may_fault = 0;
+
+ return NULL;
+}
+
+
+/*
+ * Weak aliases for breakpoint management,
+ * can be overriden by architectures when needed:
+ */
+int __weak kgdb_validate_break_address(unsigned long addr)
+{
+ char tmp_variable[BREAK_INSTR_SIZE];
+
+ if (!kgdb_get_mem((char *)addr, tmp_variable, BREAK_INSTR_SIZE))
+ return 0;
+ return -1;
+}
+
+int __weak kgdb_arch_set_breakpoint(unsigned long addr, char *saved_instr)
+{
+ if (kgdb_get_mem((char *)addr, saved_instr, BREAK_INSTR_SIZE))
+ return -1;
+
+ if (kgdb_set_mem((char *)addr, arch_kgdb_ops.gdb_bpt_instr,
+ BREAK_INSTR_SIZE))
+ return -1;
+ return 0;
+}
+
+int __weak kgdb_arch_remove_breakpoint(unsigned long addr, char *bundle)
+{
+ if (kgdb_set_mem((char *)addr, (char *)bundle, BREAK_INSTR_SIZE))
+ return -1;
+ return 0;
+}
+
+unsigned long __weak kgdb_arch_pc(int exception, struct pt_regs *regs)
+{
+ return instruction_pointer(regs);
+}
+
+/*
+ * GDB remote protocol parser:
+ */
+
+static const char hexchars[] = "0123456789abcdef";
+
+static int hex(char ch)
+{
+ if ((ch >= 'a') && (ch <= 'f'))
+ return ch - 'a' + 10;
+ if ((ch >= '0') && (ch <= '9'))
+ return ch - '0';
+ if ((ch >= 'A') && (ch <= 'F'))
+ return ch - 'A' + 10;
+ return -1;
+}
+
+/* scan for the sequence $<data>#<checksum> */
+static void get_packet(char *buffer)
+{
+ unsigned char checksum;
+ unsigned char xmitcsum;
+ int count;
+ char ch;
+
+ do {
+ /*
+ * Spin and wait around for the start character, ignore all
+ * other characters:
+ */
+ while ((ch = (kgdb_io_ops->read_char())) != '$')
+ /* nothing */;
+
+ kgdb_connected = 1;
+ checksum = 0;
+ xmitcsum = -1;
+
+ count = 0;
+
+ /*
+ * now, read until a # or end of buffer is found:
+ */
+ while (count < (BUFMAX - 1)) {
+ ch = kgdb_io_ops->read_char();
+ if (ch == '#')
+ break;
+ checksum = checksum + ch;
+ buffer[count] = ch;
+ count = count + 1;
+ }
+ buffer[count] = 0;
+
+ if (ch == '#') {
+ xmitcsum = hex(kgdb_io_ops->read_char()) << 4;
+ xmitcsum += hex(kgdb_io_ops->read_char());
+
+ if (checksum != xmitcsum)
+ /* failed checksum */
+ kgdb_io_ops->write_char('-');
+ else
+ /* successful transfer */
+ kgdb_io_ops->write_char('+');
+ if (kgdb_io_ops->flush)
+ kgdb_io_ops->flush();
+ }
+ } while (checksum != xmitcsum);
+}
+
+/*
+ * Send the packet in buffer.
+ * Check for gdb connection if asked for.
+ */
+static void put_packet(char *buffer)
+{
+ unsigned char checksum;
+ int count;
+ char ch;
+
+ /*
+ * $<packet info>#<checksum>.
+ */
+ while (1) {
+ kgdb_io_ops->write_char('$');
+ checksum = 0;
+ count = 0;
+
+ while ((ch = buffer[count])) {
+ kgdb_io_ops->write_char(ch);
+ checksum += ch;
+ count++;
+ }
+
+ kgdb_io_ops->write_char('#');
+ kgdb_io_ops->write_char(hexchars[checksum >> 4]);
+ kgdb_io_ops->write_char(hexchars[checksum % 16]);
+ if (kgdb_io_ops->flush)
+ kgdb_io_ops->flush();
+
+ /* Now see what we get in reply. */
+ ch = kgdb_io_ops->read_char();
+
+ if (ch == 3)
+ ch = kgdb_io_ops->read_char();
+
+ /* If we get an ACK, we are done. */
+ if (ch == '+')
+ return;
+
+ /*
+ * If we get the start of another packet, this means
+ * that GDB is attempting to reconnect. We will NAK
+ * the packet being sent, and stop trying to send this
+ * packet.
+ */
+ if (ch == '$') {
+ kgdb_io_ops->write_char('-');
+ if (kgdb_io_ops->flush)
+ kgdb_io_ops->flush();
+ return;
+ }
+ }
+}
+
+/*
+ * Fault-tolerant memory accessor wrappers. Performance is a secondary
+ * concern, the primary concern is not to crash the debugger (or the
+ * debuggee):
+ */
+
+/*
+ * Convert the memory pointed to by mem into hex, placing result in buf.
+ * Return a pointer to the last char put in buf (null). May return an error.
+ */
+char *kgdb_mem2hex(char *mem, char *buf, int count)
+{
+ /*
+ * Accessing some registers in a single load instruction is
+ * required to avoid bad side effects for some I/O registers.
+ */
+ if ((count == 2) && (((long)mem & 1) == 0)) {
+ u16 tmp_s;
+
+ if (probe_kernel_address(mem, tmp_s)) {
+ kgdb_may_fault = 0;
+ return ERR_PTR(-EINVAL);
+ }
+
+ mem += 2;
+#ifdef __BIG_ENDIAN
+ *buf++ = hexchars[(tmp_s >> 12) & 0xf];
+ *buf++ = hexchars[(tmp_s >> 8) & 0xf];
+ *buf++ = hexchars[(tmp_s >> 4) & 0xf];
+ *buf++ = hexchars[tmp_s & 0xf];
+#else
+ *buf++ = hexchars[(tmp_s >> 4) & 0xf];
+ *buf++ = hexchars[tmp_s & 0xf];
+ *buf++ = hexchars[(tmp_s >> 12) & 0xf];
+ *buf++ = hexchars[(tmp_s >> 8) & 0xf];
+#endif
+ } else if ((count == 4) && (((long)mem & 3) == 0)) {
+ u32 tmp_l;
+ if (probe_kernel_address(mem, tmp_l)) {
+ kgdb_may_fault = 0;
+ return ERR_PTR(-EINVAL);
+ }
+
+ mem += 4;
+#ifdef __BIG_ENDIAN
+ *buf++ = hexchars[(tmp_l >> 28) & 0xf];
+ *buf++ = hexchars[(tmp_l >> 24) & 0xf];
+ *buf++ = hexchars[(tmp_l >> 20) & 0xf];
+ *buf++ = hexchars[(tmp_l >> 16) & 0xf];
+ *buf++ = hexchars[(tmp_l >> 12) & 0xf];
+ *buf++ = hexchars[(tmp_l >> 8) & 0xf];
+ *buf++ = hexchars[(tmp_l >> 4) & 0xf];
+ *buf++ = hexchars[tmp_l & 0xf];
+#else
+ *buf++ = hexchars[(tmp_l >> 4) & 0xf];
+ *buf++ = hexchars[tmp_l & 0xf];
+ *buf++ = hexchars[(tmp_l >> 12) & 0xf];
+ *buf++ = hexchars[(tmp_l >> 8) & 0xf];
+ *buf++ = hexchars[(tmp_l >> 20) & 0xf];
+ *buf++ = hexchars[(tmp_l >> 16) & 0xf];
+ *buf++ = hexchars[(tmp_l >> 28) & 0xf];
+ *buf++ = hexchars[(tmp_l >> 24) & 0xf];
+#endif
+#ifdef CONFIG_64BIT
+ } else if ((count == 8) && (((long)mem & 7) == 0)) {
+ u64 tmp_ll;
+ if (probe_kernel_address(mem, tmp_ll)) {
+ kgdb_may_fault = 0;
+ return ERR_PTR(-EINVAL);
+ }
+
+ mem += 8;
+#ifdef __BIG_ENDIAN
+ *buf++ = hexchars[(tmp_ll >> 60) & 0xf];
+ *buf++ = hexchars[(tmp_ll >> 56) & 0xf];
+ *buf++ = hexchars[(tmp_ll >> 52) & 0xf];
+ *buf++ = hexchars[(tmp_ll >> 48) & 0xf];
+ *buf++ = hexchars[(tmp_ll >> 44) & 0xf];
+ *buf++ = hexchars[(tmp_ll >> 40) & 0xf];
+ *buf++ = hexchars[(tmp_ll >> 36) & 0xf];
+ *buf++ = hexchars[(tmp_ll >> 32) & 0xf];
+ *buf++ = hexchars[(tmp_ll >> 28) & 0xf];
+ *buf++ = hexchars[(tmp_ll >> 24) & 0xf];
+ *buf++ = hexchars[(tmp_ll >> 20) & 0xf];
+ *buf++ = hexchars[(tmp_ll >> 16) & 0xf];
+ *buf++ = hexchars[(tmp_ll >> 12) & 0xf];
+ *buf++ = hexchars[(tmp_ll >> 8) & 0xf];
+ *buf++ = hexchars[(tmp_ll >> 4) & 0xf];
+ *buf++ = hexchars[tmp_ll & 0xf];
+#else
+ *buf++ = hexchars[(tmp_ll >> 4) & 0xf];
+ *buf++ = hexchars[tmp_ll & 0xf];
+ *buf++ = hexchars[(tmp_ll >> 12) & 0xf];
+ *buf++ = hexchars[(tmp_ll >> 8) & 0xf];
+ *buf++ = hexchars[(tmp_ll >> 20) & 0xf];
+ *buf++ = hexchars[(tmp_ll >> 16) & 0xf];
+ *buf++ = hexchars[(tmp_ll >> 28) & 0xf];
+ *buf++ = hexchars[(tmp_ll >> 24) & 0xf];
+ *buf++ = hexchars[(tmp_ll >> 36) & 0xf];
+ *buf++ = hexchars[(tmp_ll >> 32) & 0xf];
+ *buf++ = hexchars[(tmp_ll >> 44) & 0xf];
+ *buf++ = hexchars[(tmp_ll >> 40) & 0xf];
+ *buf++ = hexchars[(tmp_ll >> 52) & 0xf];
+ *buf++ = hexchars[(tmp_ll >> 48) & 0xf];
+ *buf++ = hexchars[(tmp_ll >> 60) & 0xf];
+ *buf++ = hexchars[(tmp_ll >> 56) & 0xf];
+#endif
+#endif
+ } else {
+ while (count-- > 0) {
+ unsigned char ch;
+
+ if (probe_kernel_address(mem, ch)) {
+ kgdb_may_fault = 0;
+ return ERR_PTR(-EINVAL);
+ }
+ mem++;
+ *buf++ = hexchars[ch >> 4];
+ *buf++ = hexchars[ch & 0xf];
+ }
+ }
+
+ kgdb_may_fault = 0;
+ *buf = 0;
+
+ return buf;
+}
+
+/*
+ * Copy the binary array pointed to by buf into mem. Fix $, #, and
+ * 0x7d escaped with 0x7d. Return a pointer to the character after
+ * the last byte written.
+ */
+static char *kgdb_ebin2mem(char *buf, char *mem, int count)
+{
+ for (; count > 0; count--, buf++) {
+ if (*buf == 0x7d) {
+ if (probe_kernel_write(mem, (char)(*buf ^ 0x20))) {
+ kgdb_may_fault = 0;
+ return ERR_PTR(-EINVAL);
+ }
+ buf++;
+ } else {
+ if (probe_kernel_write(mem, *buf)) {
+ kgdb_may_fault = 0;
+ return ERR_PTR(-EINVAL);
+ }
+ }
+ mem++;
+ }
+ kgdb_may_fault = 0;
+
+ return mem;
+}
+
+/*
+ * Convert the hex array pointed to by buf into binary to be placed in mem.
+ * Return a pointer to the character AFTER the last byte written.
+ * May return an error.
+ */
+char *kgdb_hex2mem(char *buf, char *mem, int count)
+{
+ if ((count == 2) && (((long)mem & 1) == 0)) {
+ u16 tmp_s = 0;
+
+#ifdef __BIG_ENDIAN
+ tmp_s |= hex(*buf++) << 12;
+ tmp_s |= hex(*buf++) << 8;
+ tmp_s |= hex(*buf++) << 4;
+ tmp_s |= hex(*buf++);
+#else
+ tmp_s |= hex(*buf++) << 4;
+ tmp_s |= hex(*buf++);
+ tmp_s |= hex(*buf++) << 12;
+ tmp_s |= hex(*buf++) << 8;
+#endif
+ if (probe_kernel_write(mem, tmp_s)) {
+ kgdb_may_fault = 0;
+ return ERR_PTR(-EINVAL);
+ }
+ mem += 2;
+ } else if ((count == 4) && (((long)mem & 3) == 0)) {
+ u32 tmp_l = 0;
+
+#ifdef __BIG_ENDIAN
+ tmp_l |= hex(*buf++) << 28;
+ tmp_l |= hex(*buf++) << 24;
+ tmp_l |= hex(*buf++) << 20;
+ tmp_l |= hex(*buf++) << 16;
+ tmp_l |= hex(*buf++) << 12;
+ tmp_l |= hex(*buf++) << 8;
+ tmp_l |= hex(*buf++) << 4;
+ tmp_l |= hex(*buf++);
+#else
+ tmp_l |= hex(*buf++) << 4;
+ tmp_l |= hex(*buf++);
+ tmp_l |= hex(*buf++) << 12;
+ tmp_l |= hex(*buf++) << 8;
+ tmp_l |= hex(*buf++) << 20;
+ tmp_l |= hex(*buf++) << 16;
+ tmp_l |= hex(*buf++) << 28;
+ tmp_l |= hex(*buf++) << 24;
+#endif
+ if (probe_kernel_write(mem, tmp_l)) {
+ kgdb_may_fault = 0;
+ return ERR_PTR(-EINVAL);
+ }
+ mem += 4;
+ } else {
+ int i;
+
+ for (i = 0; i < count; i++) {
+ unsigned char ch = hex(*buf++) << 4;
+
+ ch |= hex(*buf++);
+ if (probe_kernel_write(mem, ch)) {
+ kgdb_may_fault = 0;
+ return ERR_PTR(-EINVAL);
+ }
+ mem++;
+ }
+ }
+ kgdb_may_fault = 0;
+
+ return mem;
+}
+
+/*
+ * While we find nice hex chars, build a long_val.
+ * Return number of chars processed.
+ */
+int kgdb_hex2long(char **ptr, long *long_val)
+{
+ int hex_val;
+ int num = 0;
+
+ *long_val = 0;
+
+ while (**ptr) {
+ hex_val = hex(**ptr);
+ if (hex_val >= 0) {
+ *long_val = (*long_val << 4) | hex_val;
+ num++;
+ } else
+ break;
+
+ (*ptr)++;
+ }
+
+ return num;
+}
+
+/* Write memory due to an 'M' or 'X' packet. */
+static char *write_mem_msg(int binary)
+{
+ char *ptr = &remcom_in_buffer[1];
+ unsigned long addr;
+ unsigned long length;
+
+ if (kgdb_hex2long(&ptr, &addr) > 0 && *(ptr++) == ',' &&
+ kgdb_hex2long(&ptr, &length) > 0 && *(ptr++) == ':') {
+ if (binary)
+ ptr = kgdb_ebin2mem(ptr, (char *)addr, length);
+ else
+ ptr = kgdb_hex2mem(ptr, (char *)addr, length);
+ if (IS_ERR(ptr))
+ return ptr;
+ if (CACHE_FLUSH_IS_SAFE)
+ flush_icache_range(addr, addr + length + 1);
+ return NULL;
+ }
+
+ return ERR_PTR(-EINVAL);
+}
+
+static inline char *pack_hex_byte(char *pkt, int byte)
+{
+ *pkt++ = hexchars[(byte >> 4) & 0xf];
+ *pkt++ = hexchars[(byte & 0xf)];
+
+ return pkt;
+}
+
+static inline void error_packet(char *pkt, int error)
+{
+ error = -error;
+ pkt[0] = 'E';
+ pkt[1] = hexchars[(error / 10)];
+ pkt[2] = hexchars[(error % 10)];
+ pkt[3] = '\0';
+}
+
+/*
+ * Black magic portion #2. Thread ID accessors.
+ */
+
+static char *pack_threadid(char *pkt, unsigned char *id)
+{
+ char *limit;
+
+ limit = pkt + BUF_THREAD_ID_SIZE;
+ while (pkt < limit)
+ pkt = pack_hex_byte(pkt, *id++);
+
+ return pkt;
+}
+
+static void int_to_threadref(unsigned char *id, int value)
+{
+ unsigned char *scan;
+ int i = 4;
+
+ scan = (unsigned char *)id;
+ while (i--)
+ *scan++ = 0;
+ *scan++ = (value >> 24) & 0xff;
+ *scan++ = (value >> 16) & 0xff;
+ *scan++ = (value >> 8) & 0xff;
+ *scan++ = (value & 0xff);
+}
+
+static struct task_struct *getthread(struct pt_regs *regs, int tid)
+{
+ if (init_pid_ns.last_pid == 0)
+ return current;
+
+ if (num_online_cpus() && (tid >= pid_max + num_online_cpus() +
+ arch_kgdb_ops.shadowth))
+ return NULL;
+
+ if (arch_kgdb_ops.shadowth && (tid >= pid_max + num_online_cpus())) {
+ return kgdb_get_shadow_thread(regs, tid - pid_max -
+ num_online_cpus());
+ }
+
+ if (tid >= pid_max)
+ return idle_task(tid - pid_max);
+
+ if (!tid)
+ return NULL;
+
+ /*
+ * find_task_by_pid() does not take the tasklist lock anymore
+ * but is nicely RCU locked - hence is a pretty resilient
+ * thing to use:
+ */
+ return find_task_by_pid(tid);
+}
+
+/*
+ * CPU debug state control:
+ */
+
+#ifdef CONFIG_SMP
+static void kgdb_wait(struct pt_regs *regs)
+{
+ unsigned long flags;
+ int cpu;
+
+ local_irq_save(flags);
+ cpu = raw_smp_processor_id();
+ kgdb_info[cpu].debuggerinfo = regs;
+ kgdb_info[cpu].task = current;
+ atomic_set(&cpu_in_kgdb[cpu], 1);
+
+ /*
+ * The master CPU must be active to enter here, but this is
+ * gaurd in case the master CPU had not been selected if
+ * this was an entry via nmi.
+ */
+ while (!atomic_read(&debugger_active))
+ cpu_relax();
+
+ /* Wait till master CPU goes completely into the debugger. */
+ while (!atomic_read(&cpu_in_kgdb[atomic_read(&debugger_active) - 1])) {
+ int i = 10; /* an arbitrary number. Be nice. A bit. */
+
+ while (--i)
+ cpu_relax();
+ }
+
+ /* Wait till master CPU is done with debugging */
+ spin_lock(&slave_cpu_locks[cpu]);
+
+ kgdb_info[cpu].debuggerinfo = NULL;
+ kgdb_info[cpu].task = NULL;
+
+ /* fix up hardware debug registers on local cpu */
+ if (arch_kgdb_ops.correct_hw_break)
+ arch_kgdb_ops.correct_hw_break();
+
+ /* Signal the master CPU that we are done: */
+ atomic_set(&cpu_in_kgdb[cpu], 0);
+ spin_unlock(&slave_cpu_locks[cpu]);
+ local_irq_restore(flags);
+}
+#endif
+
+/*
+ * SW breakpoint management:
+ */
+static int kgdb_activate_sw_breakpoints(void)
+{
+ unsigned long addr;
+ int error = 0;
+ int i;
+
+ for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+ if (kgdb_break[i].state != BP_SET)
+ continue;
+
+ addr = kgdb_break[i].bpt_addr;
+ error = kgdb_arch_set_breakpoint(addr,
+ kgdb_break[i].saved_instr);
+ if (error)
+ return error;
+
+ if (CACHE_FLUSH_IS_SAFE) {
+ if (current->mm && addr < TASK_SIZE) {
+ flush_cache_range(current->mm->mmap_cache,
+ addr, addr + BREAK_INSTR_SIZE);
+ } else {
+ flush_icache_range(addr, addr +
+ BREAK_INSTR_SIZE);
+ }
+ }
+ kgdb_break[i].state = BP_ACTIVE;
+ }
+ return 0;
+}
+
+static int kgdb_set_sw_break(unsigned long addr)
+{
+ int error = kgdb_validate_break_address(addr);
+ int breakno = -1;
+ int i;
+
+ if (error < 0)
+ return error;
+
+ for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+ if ((kgdb_break[i].state == BP_SET) &&
+ (kgdb_break[i].bpt_addr == addr))
+ return -EEXIST;
+ }
+ for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+ if (kgdb_break[i].state == BP_REMOVED &&
+ kgdb_break[i].bpt_addr == addr) {
+ breakno = i;
+ break;
+ }
+ }
+
+ if (breakno == -1) {
+ for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+ if (kgdb_break[i].state == BP_UNDEFINED) {
+ breakno = i;
+ break;
+ }
+ }
+ }
+
+ if (breakno == -1)
+ return -E2BIG;
+
+ kgdb_break[breakno].state = BP_SET;
+ kgdb_break[breakno].type = BP_BREAKPOINT;
+ kgdb_break[breakno].bpt_addr = addr;
+
+ return 0;
+}
+
+static int kgdb_deactivate_sw_breakpoints(void)
+{
+ unsigned long addr;
+ int error = 0;
+ int i;
+
+ for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+ if (kgdb_break[i].state != BP_ACTIVE)
+ continue;
+ addr = kgdb_break[i].bpt_addr;
+ error = kgdb_arch_remove_breakpoint(addr,
+ kgdb_break[i].saved_instr);
+ if (error)
+ return error;
+
+ if (CACHE_FLUSH_IS_SAFE && current->mm &&
+ addr < TASK_SIZE) {
+ flush_cache_range(current->mm->mmap_cache,
+ addr, addr + BREAK_INSTR_SIZE);
+ } else if (CACHE_FLUSH_IS_SAFE) {
+ flush_icache_range(addr, addr + BREAK_INSTR_SIZE);
+ }
+ kgdb_break[i].state = BP_SET;
+ }
+ return 0;
+}
+
+static int kgdb_remove_sw_break(unsigned long addr)
+{
+ int i;
+
+ for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+ if ((kgdb_break[i].state == BP_SET) &&
+ (kgdb_break[i].bpt_addr == addr)) {
+ kgdb_break[i].state = BP_REMOVED;
+ return 0;
+ }
+ }
+ return -ENOENT;
+}
+
+int kgdb_isremovedbreak(unsigned long addr)
+{
+ int i;
+
+ for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+ if ((kgdb_break[i].state == BP_REMOVED) &&
+ (kgdb_break[i].bpt_addr == addr))
+ return 1;
+ }
+ return 0;
+}
+
+int remove_all_break(void)
+{
+ unsigned long addr;
+ int error;
+ int i;
+
+ /* Clear memory breakpoints. */
+ for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+ if (kgdb_break[i].state != BP_SET)
+ continue;
+ addr = kgdb_break[i].bpt_addr;
+ error = kgdb_arch_remove_breakpoint(addr,
+ kgdb_break[i].saved_instr);
+ if (error)
+ return error;
+ kgdb_break[i].state = BP_REMOVED;
+ }
+
+ /* Clear hardware breakpoints. */
+ if (arch_kgdb_ops.remove_all_hw_break)
+ arch_kgdb_ops.remove_all_hw_break();
+
+ return 0;
+}
+
+static inline int shadow_pid(int realpid)
+{
+ if (realpid)
+ return realpid;
+
+ return pid_max + raw_smp_processor_id();
+}
+
+static char gdbmsgbuf[BUFMAX + 1];
+
+static void kgdb_msg_write(const char *s, int len)
+{
+ char *bufptr;
+ int wcount;
+ int i;
+
+ /* 'O'utput */
+ gdbmsgbuf[0] = 'O';
+
+ /* Fill and send buffers... */
+ while (len > 0) {
+ bufptr = gdbmsgbuf + 1;
+
+ /* Calculate how many this time */
+ if ((len << 1) > (BUFMAX - 2))
+ wcount = (BUFMAX - 2) >> 1;
+ else
+ wcount = len;
+
+ /* Pack in hex chars */
+ for (i = 0; i < wcount; i++)
+ bufptr = pack_hex_byte(bufptr, s[i]);
+ *bufptr = '\0';
+
+ /* Move up */
+ s += wcount;
+ len -= wcount;
+
+ /* Write packet */
+ put_packet(gdbmsgbuf);
+ }
+}
+
+/*
+ * Return true if there is a valid kgdb I/O module. Also if no
+ * debugger is attached a message can be printed to the console about
+ * waiting for the debugger to attach.
+ *
+ * The print_wait argument is only to be true when called from inside
+ * the core kgdb_handle_exception, because it will wait for the
+ * debugger to attach.
+ */
+int kgdb_io_ready(int print_wait)
+{
+ if (!kgdb_io_ops)
+ return 0;
+ if (kgdb_connected)
+ return 1;
+ if (atomic_read(&kgdb_setting_breakpoint))
+ return 1;
+ if (print_wait)
+ printk(KERN_CRIT "KGDB: Waiting for remote debugger\n");
+ return 1;
+}
+
+/*
+ * All the functions that start with gdb_cmd are the various
+ * operations to implement the handlers for the gdbserial protocol
+ * where KGDB is communicating with an external debugger
+ */
+
+/* Handle the '?' status packets */
+static void gdb_cmd_status(struct kgdb_state *ks)
+{
+ /*
+ * We know that this packet is only sent
+ * during initial connect. So to be safe,
+ * we clear out our breakpoints now in case
+ * GDB is reconnecting.
+ */
+ remove_all_break();
+
+ /*
+ * Also, if we haven't been able to roundup all
+ * CPUs, send an 'O' packet informing the user
+ * as much. Only need to do this once.
+ */
+ if (!ks->all_cpus_synced)
+ kgdb_msg_write("Not all CPUs have been synced for KGDB\n", 39);
+
+ remcom_out_buffer[0] = 'S';
+ remcom_out_buffer[1] = hexchars[ks->signo >> 4];
+ remcom_out_buffer[2] = hexchars[ks->signo % 16];
+}
+
+/* Handle the 'g' get registers request */
+static void gdb_cmd_getregs(struct kgdb_state *ks)
+{
+ struct pt_regs *shadowregs;
+ struct task_struct *thread;
+ void *local_debuggerinfo;
+ int i;
+
+ thread = kgdb_usethread;
+ if (!thread) {
+ thread = kgdb_info[ks->cpu].task;
+ local_debuggerinfo = kgdb_info[ks->cpu].debuggerinfo;
+ } else {
+ local_debuggerinfo = NULL;
+ for (i = 0; i < NR_CPUS; i++) {
+ /*
+ * Try to find the task on some other
+ * or possibly this node if we do not
+ * find the matching task then we try
+ * to approximate the results.
+ */
+ if (thread == kgdb_info[i].task)
+ local_debuggerinfo = kgdb_info[i].debuggerinfo;
+ }
+ }
+
+ /*
+ * All threads that don't have debuggerinfo should be
+ * in __schedule() sleeping, since all other CPUs
+ * are in kgdb_wait, and thus have debuggerinfo.
+ */
+ if (arch_kgdb_ops.shadowth &&
+ ks->kgdb_usethreadid >= pid_max + num_online_cpus()) {
+
+ shadowregs = kgdb_shadow_regs(ks->linux_regs,
+ ks->kgdb_usethreadid -
+ pid_max -
+ num_online_cpus());
+ if (!shadowregs) {
+ error_packet(remcom_out_buffer, -EINVAL);
+ return;
+ }
+ pt_regs_to_gdb_regs(gdb_regs, shadowregs);
+ } else {
+ if (local_debuggerinfo) {
+ pt_regs_to_gdb_regs(gdb_regs, local_debuggerinfo);
+ } else {
+ /*
+ * Pull stuff saved during switch_to; nothing
+ * else is accessible (or even particularly
+ * relevant).
+ *
+ * This should be enough for a stack trace.
+ */
+ sleeping_thread_to_gdb_regs(gdb_regs, thread);
+ }
+ }
+ kgdb_mem2hex((char *)gdb_regs, remcom_out_buffer, NUMREGBYTES);
+}
+
+/* Handle the 'G' set registers request */
+static void gdb_cmd_setregs(struct kgdb_state *ks)
+{
+ kgdb_hex2mem(&remcom_in_buffer[1], (char *)gdb_regs, NUMREGBYTES);
+
+ if (kgdb_usethread && kgdb_usethread != current) {
+ error_packet(remcom_out_buffer, -EINVAL);
+ } else {
+ gdb_regs_to_pt_regs(gdb_regs, ks->linux_regs);
+ strcpy(remcom_out_buffer, "OK");
+ }
+}
+
+/* Handle the 'm' memory read bytes */
+static void gdb_cmd_memread(struct kgdb_state *ks)
+{
+ char *ptr = &remcom_in_buffer[1];
+ unsigned long length;
+ unsigned long addr;
+
+ if (kgdb_hex2long(&ptr, &addr) > 0 && *ptr++ == ',' &&
+ kgdb_hex2long(&ptr, &length) > 0) {
+
+ ptr = kgdb_mem2hex((char *)addr, remcom_out_buffer, length);
+ if (IS_ERR(ptr))
+ error_packet(remcom_out_buffer, PTR_ERR(ptr));
+ } else {
+ error_packet(remcom_out_buffer, -EINVAL);
+ }
+}
+
+/* Handle the 'M' memory write bytes */
+static void gdb_cmd_memwrite(struct kgdb_state *ks)
+{
+ char *ptr = write_mem_msg(0);
+
+ if (IS_ERR(ptr))
+ error_packet(remcom_out_buffer, PTR_ERR(ptr));
+ else
+ strcpy(remcom_out_buffer, "OK");
+}
+
+/* Handle the 'X' memory binary write bytes */
+static void gdb_cmd_binwrite(struct kgdb_state *ks)
+{
+ char *ptr = write_mem_msg(1);
+
+ if (IS_ERR(ptr))
+ error_packet(remcom_out_buffer, PTR_ERR(ptr));
+ else
+ strcpy(remcom_out_buffer, "OK");
+}
+
+/* Handle the 'D' or 'k', detach or kill packets */
+static void gdb_cmd_detachkill(struct kgdb_state *ks)
+{
+ int error;
+
+ /* The detach case */
+ if (remcom_in_buffer[0] == 'D') {
+ error = remove_all_break();
+ if (error < 0) {
+ error_packet(remcom_out_buffer, error);
+ } else {
+ strcpy(remcom_out_buffer, "OK");
+ kgdb_connected = 0;
+ }
+ put_packet(remcom_out_buffer);
+ } else {
+ /*
+ * Assume the kill case, with no exit code checking,
+ * trying to force detach the debugger:
+ */
+ remove_all_break();
+ kgdb_connected = 0;
+ }
+}
+
+/* Handle the 'R' reboot packets */
+static int gdb_cmd_reboot(struct kgdb_state *ks)
+{
+ /* For now, only honor R0 */
+ if (strcmp(remcom_in_buffer, "R0") == 0) {
+ printk(KERN_CRIT "Executing reboot\n");
+ strcpy(remcom_out_buffer, "OK");
+ put_packet(remcom_out_buffer);
+ emergency_sync();
+
+ /*
+ * Execution should not return from
+ * machine_restart()
+ */
+ machine_restart(NULL);
+ kgdb_connected = 0;
+
+ return 1;
+ }
+ return 0;
+}
+
+/* Handle the 'q' query packets */
+static void gdb_cmd_query(struct kgdb_state *ks)
+{
+ int numshadowth = num_online_cpus() + arch_kgdb_ops.shadowth;
+ struct task_struct *thread;
+ unsigned char thref[8];
+ char *ptr;
+ int i;
+
+ switch (remcom_in_buffer[1]) {
+ case 's':
+ case 'f':
+ if (memcmp(remcom_in_buffer + 2, "ThreadInfo", 10)) {
+ error_packet(remcom_out_buffer, -EINVAL);
+ break;
+ }
+
+ /*
+ * If we have not yet completed in
+ * pidhash_init() there isn't much we
+ * can give back.
+ */
+ if (init_pid_ns.last_pid == 0) {
+ if (remcom_in_buffer[1] == 'f')
+ strcpy(remcom_out_buffer, "m0000000000000001");
+ break;
+ }
+
+ if (remcom_in_buffer[1] == 'f')
+ ks->threadid = 1;
+
+ remcom_out_buffer[0] = 'm';
+ ptr = remcom_out_buffer + 1;
+
+ for (i = 0; i < 17 && ks->threadid < pid_max + numshadowth;
+ ks->threadid++) {
+
+ thread = getthread(ks->linux_regs, ks->threadid);
+ if (thread) {
+ int_to_threadref(thref, ks->threadid);
+ pack_threadid(ptr, thref);
+ ptr += 16;
+ *(ptr++) = ',';
+ i++;
+ }
+ }
+ *(--ptr) = '\0';
+ break;
+
+ case 'C':
+ /* Current thread id */
+ strcpy(remcom_out_buffer, "QC");
+ ks->threadid = shadow_pid(current->pid);
+ int_to_threadref(thref, ks->threadid);
+ pack_threadid(remcom_out_buffer + 2, thref);
+ break;
+ case 'T':
+ if (memcmp(remcom_in_buffer + 1, "ThreadExtraInfo,", 16)) {
+ error_packet(remcom_out_buffer, -EINVAL);
+ break;
+ }
+ ks->threadid = 0;
+ ptr = remcom_in_buffer + 17;
+ kgdb_hex2long(&ptr, &ks->threadid);
+ if (!getthread(ks->linux_regs, ks->threadid)) {
+ error_packet(remcom_out_buffer, -EINVAL);
+ break;
+ }
+ if (ks->threadid < pid_max) {
+ kgdb_mem2hex(getthread(ks->linux_regs,
+ ks->threadid)->comm,
+ remcom_out_buffer, 16);
+ } else {
+ if (ks->threadid >= pid_max + num_online_cpus()) {
+ kgdb_shadowinfo(ks->linux_regs,
+ remcom_out_buffer,
+ ks->threadid - pid_max -
+ num_online_cpus());
+ } else {
+ static char tmpstr[23 + BUF_THREAD_ID_SIZE];
+ sprintf(tmpstr, "Shadow task %d for pid 0",
+ (int)(ks->threadid - pid_max));
+ kgdb_mem2hex(tmpstr, remcom_out_buffer,
+ strlen(tmpstr));
+ }
+ }
+ break;
+ }
+}
+
+/* Handle the 'H' task query packets */
+static void gdb_cmd_task(struct kgdb_state *ks)
+{
+ struct task_struct *thread;
+ char *ptr;
+
+ switch (remcom_in_buffer[1]) {
+ case 'g':
+ ptr = &remcom_in_buffer[2];
+ kgdb_hex2long(&ptr, &ks->threadid);
+ thread = getthread(ks->linux_regs, ks->threadid);
+ if (!thread && ks->threadid > 0) {
+ error_packet(remcom_out_buffer, -EINVAL);
+ break;
+ }
+ kgdb_usethread = thread;
+ ks->kgdb_usethreadid = ks->threadid;
+ strcpy(remcom_out_buffer, "OK");
+ break;
+ case 'c':
+ ptr = &remcom_in_buffer[2];
+ kgdb_hex2long(&ptr, &ks->threadid);
+ if (!ks->threadid) {
+ kgdb_contthread = NULL;
+ } else {
+ thread = getthread(ks->linux_regs, ks->threadid);
+ if (!thread && ks->threadid > 0) {
+ error_packet(remcom_out_buffer, -EINVAL);
+ break;
+ }
+ kgdb_contthread = thread;
+ }
+ strcpy(remcom_out_buffer, "OK");
+ break;
+ }
+}
+
+/* Handle the 'T' thread query packets */
+static void gdb_cmd_thread(struct kgdb_state *ks)
+{
+ char *ptr = &remcom_in_buffer[1];
+ struct task_struct *thread;
+
+ kgdb_hex2long(&ptr, &ks->threadid);
+ thread = getthread(ks->linux_regs, ks->threadid);
+ if (thread)
+ strcpy(remcom_out_buffer, "OK");
+ else
+ error_packet(remcom_out_buffer, -EINVAL);
+}
+
+/* Handle the 'z' or 'Z' breakpoint remove or set packets */
+static void gdb_cmd_break(struct kgdb_state *ks)
+{
+ /*
+ * Since GDB-5.3, it's been drafted that '0' is a software
+ * breakpoint, '1' is a hardware breakpoint, so let's do that.
+ */
+ char *bpt_type = &remcom_in_buffer[1];
+ char *ptr = &remcom_in_buffer[2];
+ unsigned long addr;
+ unsigned long length;
+ int error = 0;
+
+ if (arch_kgdb_ops.set_hw_breakpoint && *bpt_type >= '1') {
+ /* Unsupported */
+ if (*bpt_type > '4')
+ return;
+ } else {
+ if (*bpt_type != '0' && *bpt_type != '1')
+ /* Unsupported. */
+ return;
+ }
+
+ /*
+ * Test if this is a hardware breakpoint, and
+ * if we support it:
+ */
+ if (*bpt_type == '1' && !(arch_kgdb_ops.flags & KGDB_HW_BREAKPOINT))
+ /* Unsupported. */
+ return;
+
+ if (*(ptr++) != ',') {
+ error_packet(remcom_out_buffer, -EINVAL);
+ return;
+ } else {
+ if (kgdb_hex2long(&ptr, &addr)) {
+ if (*(ptr++) != ',' ||
+ !kgdb_hex2long(&ptr, &length)) {
+ error_packet(remcom_out_buffer, -EINVAL);
+ return;
+ }
+ } else {
+ error_packet(remcom_out_buffer, -EINVAL);
+ return;
+ }
+ }
+
+ if (remcom_in_buffer[0] == 'Z' && *bpt_type == '0')
+ error = kgdb_set_sw_break(addr);
+ else if (remcom_in_buffer[0] == 'z' && *bpt_type == '0')
+ error = kgdb_remove_sw_break(addr);
+ else if (remcom_in_buffer[0] == 'Z')
+ error = arch_kgdb_ops.set_hw_breakpoint(addr,
+ (int)length, *bpt_type);
+ else if (remcom_in_buffer[0] == 'z')
+ error = arch_kgdb_ops.remove_hw_breakpoint(addr,
+ (int) length, *bpt_type);
+
+ if (error == 0)
+ strcpy(remcom_out_buffer, "OK");
+ else
+ error_packet(remcom_out_buffer, error);
+}
+
+/* Handle the 'C' signal / exception passing packets */
+static int gdb_cmd_exception_pass(struct kgdb_state *ks)
+{
+ /* C09 == pass exception
+ * C15 == detach kgdb, pass exception
+ */
+ if (remcom_in_buffer[1] == '0' && remcom_in_buffer[2] == '9') {
+
+ ks->pass_exception = 1;
+ remcom_in_buffer[0] = 'c';
+
+ } else if (remcom_in_buffer[1] == '1' && remcom_in_buffer[2] == '5') {
+
+ ks->pass_exception = 1;
+ remcom_in_buffer[0] = 'D';
+ remove_all_break();
+ kgdb_connected = 0;
+ return 1;
+
+ } else {
+ error_packet(remcom_out_buffer, -EINVAL);
+ return 0;
+ }
+
+ /* Indicate fall through */
+ return -1;
+}
+
+/*
+ * This function performs all gdbserial command procesing
+ */
+static int gdb_serial_stub(struct kgdb_state *ks)
+{
+ int error = 0;
+ int tmp;
+
+ /* Clear the out buffer. */
+ memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer));
+
+ if (kgdb_connected) {
+ unsigned char thref[8];
+ char *ptr;
+
+ /*
+ * Warn debugger if the CPUs are not synced with an 'O'
+ * packet:
+ */
+ if (!ks->all_cpus_synced) {
+ kgdb_msg_write("Not all CPUs have been synced for "
+ "KGDB\n", 39);
+ }
+ /* Reply to host that an exception has occurred */
+ ptr = remcom_out_buffer;
+ *ptr++ = 'T';
+ *ptr++ = hexchars[(ks->signo >> 4) % 16];
+ *ptr++ = hexchars[ks->signo % 16];
+ ptr += strlen(strcpy(ptr, "thread:"));
+ int_to_threadref(thref, shadow_pid(current->pid));
+ ptr = pack_threadid(ptr, thref);
+ *ptr++ = ';';
+ put_packet(remcom_out_buffer);
+ }
+
+ kgdb_usethread = kgdb_info[ks->cpu].task;
+ ks->kgdb_usethreadid = shadow_pid(kgdb_info[ks->cpu].task->pid);
+ ks->pass_exception = 0;
+
+ while (1) {
+ error = 0;
+
+ /* Clear the out buffer. */
+ memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer));
+
+ get_packet(remcom_in_buffer);
+
+ switch (remcom_in_buffer[0]) {
+ case '?': /* gdbserial status */
+ gdb_cmd_status(ks);
+ break;
+ case 'g': /* return the value of the CPU registers */
+ gdb_cmd_getregs(ks);
+ break;
+ case 'G': /* set the value of the CPU registers - return OK */
+ gdb_cmd_setregs(ks);
+ break;
+ case 'm': /* mAA..AA,LLLL Read LLLL bytes at address AA..AA */
+ gdb_cmd_memread(ks);
+ break;
+ case 'M': /* MAA..AA,LLLL: Write LLLL bytes at address AA..AA */
+ gdb_cmd_memwrite(ks);
+ break;
+ case 'X': /* XAA..AA,LLLL: Write LLLL bytes at address AA..AA */
+ gdb_cmd_binwrite(ks);
+ break;
+ /* kill or detach. KGDB should treat this like a
+ * continue.
+ */
+ case 'D': /* Debugger detach */
+ case 'k': /* Debugger detach via kill */
+ gdb_cmd_detachkill(ks);
+ goto default_handle;
+ case 'R': /* Reboot */
+ if (gdb_cmd_reboot(ks))
+ goto default_handle;
+ break;
+ case 'q': /* query command */
+ gdb_cmd_query(ks);
+ break;
+ case 'H': /* task related */
+ gdb_cmd_task(ks);
+ break;
+ case 'T': /* Query thread status */
+ gdb_cmd_thread(ks);
+ break;
+ case 'z': /* Break point remove */
+ case 'Z': /* Break point set */
+ gdb_cmd_break(ks);
+ break;
+ case 'C': /* Exception passing */
+ tmp = gdb_cmd_exception_pass(ks);
+ if (tmp > 0)
+ goto default_handle;
+ if (tmp == 0)
+ break;
+ /* Fall through on tmp < 0 */
+ case 'c': /* Continue packet */
+ case 's': /* Single step packet */
+ if (kgdb_contthread && kgdb_contthread != current) {
+ /* Can't switch threads in kgdb */
+ error_packet(remcom_out_buffer, -EINVAL);
+ break;
+ }
+ kgdb_activate_sw_breakpoints();
+ /* Fall through to default processing */
+ default:
+default_handle:
+ error = kgdb_arch_handle_exception(ks->ex_vector,
+ ks->signo,
+ ks->err_code,
+ remcom_in_buffer,
+ remcom_out_buffer,
+ ks->linux_regs);
+ /*
+ * Leave cmd processing on error, detach,
+ * kill, continue, or single step.
+ */
+ if (error >= 0 || remcom_in_buffer[0] == 'D' ||
+ remcom_in_buffer[0] == 'k') {
+ error = 0;
+ goto kgdb_exit;
+ }
+
+ }
+
+ /* reply to the request */
+ put_packet(remcom_out_buffer);
+ }
+
+kgdb_exit:
+ if (ks->pass_exception)
+ error = 1;
+ return error;
+}
+
+static int kgdb_reenter_check(struct kgdb_state *ks)
+{
+ unsigned long addr;
+
+ if (atomic_read(&debugger_active) != raw_smp_processor_id() + 1)
+ return 0;
+
+ /* Panic on recursive debugger calls: */
+ exception_level++;
+ addr = kgdb_arch_pc(ks->ex_vector, ks->linux_regs);
+ kgdb_deactivate_sw_breakpoints();
+
+ /*
+ * If the break point removed ok at the place exception
+ * occurred, try to recover and print a warning to the end
+ * user because the user planted a breakpoint in a place that
+ * KGDB needs in order to function.
+ */
+ if (kgdb_remove_sw_break(addr) == 0) {
+ exception_level = 0;
+ kgdb_skipexception(ks->ex_vector, ks->linux_regs);
+ kgdb_activate_sw_breakpoints();
+ printk(KERN_CRIT "KGDB: re-enter error: breakpoint removed\n");
+ WARN_ON_ONCE(1);
+
+ return 1;
+ }
+ remove_all_break();
+ kgdb_skipexception(ks->ex_vector, ks->linux_regs);
+
+ if (exception_level > 1) {
+ dump_stack();
+ panic("Recursive entry to debugger");
+ }
+
+ printk(KERN_CRIT "KGDB: re-enter exception: ALL breakpoints killed\n");
+ dump_stack();
+ panic("Recursive entry to debugger");
+
+ return 1;
+}
+
+/*
+ * kgdb_handle_exception() - main entry point from a kernel exception
+ *
+ * Locking hierarchy:
+ * interface locks, if any (begin_session)
+ * kgdb lock (debugger_active)
+ *
+ * Note that since we can be in here prior to our cpumask being filled
+ * out, we err on the side of caution and loop over NR_CPUS instead
+ * of a for_each_online_cpu.
+ */
+int
+kgdb_handle_exception(int evector, int signo, int ecode, struct pt_regs *regs)
+{
+ struct kgdb_state kgdb_var;
+ struct kgdb_state *ks = &kgdb_var;
+ unsigned long flags;
+ int error = 0;
+ int i, cpu;
+
+ ks->cpu = raw_smp_processor_id();
+ ks->all_cpus_synced = 0;
+ ks->ex_vector = evector;
+ ks->signo = signo;
+ ks->ex_vector = evector;
+ ks->err_code = ecode;
+ ks->kgdb_usethreadid = 0;
+ ks->linux_regs = regs;
+
+ if (kgdb_reenter_check(ks))
+ return 0; /* Ouch, double exception ! */
+
+acquirelock:
+ /*
+ * Interrupts will be restored by the 'trap return' code, except when
+ * single stepping.
+ */
+ local_irq_save(flags);
+
+ cpu = raw_smp_processor_id();
+
+ /*
+ * Being the process of declaring a master debug processor, the
+ * goal is to have only one single processor set debugger_active
+ * to the number of the cpu + 1. The atomic variable kgdb_sync is
+ * used to control the selection.
+ */
+ while (1) {
+ i = 25; /* an arbitrary number */
+ if (atomic_read(&kgdb_sync) < 0 &&
+ atomic_inc_and_test(&kgdb_sync)) {
+ atomic_set(&debugger_active, cpu + 1);
+ break;
+ }
+
+ while (--i)
+ cpu_relax();
+
+ if (atomic_read(&cpu_doing_single_step) != -1 &&
+ atomic_read(&cpu_doing_single_step) != cpu)
+ udelay(1);
+ }
+
+ /*
+ * Do not start the debugger connection on this CPU if the last
+ * instance of the exception handler wanted to come into the
+ * debugger on a different CPU via a single step
+ */
+ if (atomic_read(&cpu_doing_single_step) != -1 &&
+ atomic_read(&cpu_doing_single_step) != cpu) {
+
+ atomic_set(&debugger_active, 0);
+ atomic_set(&kgdb_sync, -1);
+ local_irq_restore(flags);
+
+ goto acquirelock;
+ }
+
+ if (!kgdb_io_ready(1)) {
+ error = 1;
+ goto kgdb_restore; /* No I/O connection, so resume the system */
+ }
+
+ /*
+ * Don't enter if we have hit a removed breakpoint.
+ */
+ if (kgdb_skipexception(ks->ex_vector, ks->linux_regs))
+ goto kgdb_restore;
+
+ /* Call the I/O driver's pre_exception routine */
+ if (kgdb_io_ops->pre_exception)
+ kgdb_io_ops->pre_exception();
+
+ kgdb_info[ks->cpu].debuggerinfo = ks->linux_regs;
+ kgdb_info[ks->cpu].task = current;
+
+ kgdb_disable_hw_debug(ks->linux_regs);
+
+ /*
+ * Get the slave CPU lock which will hold all the non-master
+ * CPU in a spin state while the debugger is active
+ */
+ if (!debugger_step || !kgdb_contthread) {
+ for (i = 0; i < NR_CPUS; i++)
+ spin_lock(&slave_cpu_locks[i]);
+ }
+
+#ifdef CONFIG_SMP
+ /* Signal the other CPUs to enter kgdb_wait() */
+ if (!debugger_step || !kgdb_contthread)
+ kgdb_roundup_cpus(flags);
+#endif
+
+ /*
+ * spin_lock code is good enough as a barrier so we don't
+ * need one here:
+ */
+ atomic_set(&cpu_in_kgdb[ks->cpu], 1);
+
+ /*
+ * Wait a reasonable time for the other CPUs to be notified and
+ * be waiting for us. Very early on this could be imperfect
+ * as num_online_cpus() could be 0.
+ */
+ for (i = 0; i < ROUNDUP_WAIT; i++) {
+ int num = 0;
+ int n;
+
+ for (n = 0; n < NR_CPUS; n++) {
+ if (atomic_read(&cpu_in_kgdb[n]))
+ num++;
+ }
+ if (num >= num_online_cpus()) {
+ ks->all_cpus_synced = 1;
+ break;
+ }
+ }
+
+ /* Master processor is completely in the debugger */
+ kgdb_post_master_code(ks->linux_regs, ks->ex_vector, ks->err_code);
+ kgdb_deactivate_sw_breakpoints();
+ debugger_step = 0;
+ kgdb_contthread = NULL;
+ exception_level = 0;
+
+ /* Talk to debugger with gdbserial protocol */
+ error = gdb_serial_stub(ks);
+
+ /* Call the I/O driver's post_exception routine */
+ if (kgdb_io_ops->post_exception)
+ kgdb_io_ops->post_exception();
+
+ kgdb_info[ks->cpu].debuggerinfo = NULL;
+ kgdb_info[ks->cpu].task = NULL;
+ atomic_set(&cpu_in_kgdb[ks->cpu], 0);
+
+ if (!debugger_step || !kgdb_contthread) {
+ for (i = NR_CPUS-1; i >= 0; i--)
+ spin_unlock(&slave_cpu_locks[i]);
+ /*
+ * Wait till all the CPUs have quit
+ * from the debugger.
+ */
+ for (i = 0; i < NR_CPUS; i++) {
+ while (atomic_read(&cpu_in_kgdb[i])) {
+ int j = 10; /* an arbitrary number */
+
+ while (--j)
+ cpu_relax();
+ }
+ }
+ }
+
+#ifdef CONFIG_SMP
+ /*
+ * This delay has a real purpose. The problem is that if you
+ * are single-stepping, you are sending an NMI to all the
+ * other CPUs to stop them. Interrupts come in, but don't get
+ * handled. Then you let them go just long enough to get into
+ * their interrupt routines and use up some stack. You stop them
+ * again, and then do the same thing. After a while you blow
+ * the stack on the other CPUs. This delay gives some time for
+ * interrupts to be cleared out on the other CPUs.
+ */
+ if (debugger_step)
+ mdelay(2);
+#endif
+kgdb_restore:
+ /* Free debugger_active */
+ atomic_set(&debugger_active, 0);
+ atomic_set(&kgdb_sync, -1);
+ local_irq_restore(flags);
+
+ return error;
+}
+
+/*
+ * 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;
+}
+
+static struct notifier_block kgdb_module_load_nb = {
+ .notifier_call = module_event,
+};
+
+int kgdb_nmicallback(int cpu, void *regs)
+{
+#ifdef CONFIG_SMP
+ if (!atomic_read(&cpu_in_kgdb[cpu]) &&
+ atomic_read(&debugger_active) != (cpu + 1)) {
+ kgdb_wait((struct pt_regs *)regs);
+ return 0;
+ }
+#endif
+ return 1;
+}
+
+/*
+ * This is called when a panic happens. All we need to do is
+ * kgdb_breakpoint().
+ */
+static int
+kgdb_panic_notify(struct notifier_block *self, unsigned long cmd, void *ptr)
+{
+ if (atomic_read(&debugger_active) != 0) {
+ printk(KERN_ERR "KGDB: Cannot handle panic while"
+ "debugger active\n");
+ dump_stack();
+ return NOTIFY_DONE;
+ }
+ printk(KERN_ERR "kgdb panic point\n");
+ kgdb_breakpoint();
+
+ return NOTIFY_DONE;
+}
+
+static struct notifier_block kgdb_panic_notifier = {
+ .notifier_call = kgdb_panic_notify,
+};
+
+#ifdef CONFIG_KGDB_CONSOLE_OUTPUT
+
+void kgdb_console_write(struct console *co, const char *s, unsigned count)
+{
+ unsigned long flags;
+
+ /* If we're debugging, or KGDB has not connected, don't try
+ * and print. */
+ if (!kgdb_connected || atomic_read(&debugger_active) != 0)
+ return;
+
+ local_irq_save(flags);
+ kgdb_msg_write(s, count);
+ local_irq_restore(flags);
+}
+
+static struct console kgdbcons = {
+ .name = "kgdb",
+ .write = kgdb_console_write,
+ .flags = CON_PRINTBUFFER | CON_ENABLED,
+ .index = -1,
+}
+;
+#endif
+
+#ifdef CONFIG_MAGIC_SYSRQ
+static void sysrq_handle_gdb(int key, struct tty_struct *tty)
+{
+ if (!kgdb_io_ops) {
+ printk(KERN_CRIT "ERROR: No KGDB I/O module available\n");
+ return;
+ }
+ if (!kgdb_connected)
+ printk(KERN_CRIT "Entering KGDB\n");
+
+ kgdb_breakpoint();
+}
+
+static struct sysrq_key_op sysrq_gdb_op = {
+ .handler = sysrq_handle_gdb,
+ .help_msg = "Gdb",
+ .action_msg = "GDB",
+};
+#endif
+
+static void kgdb_register_callbacks(void)
+{
+ if (!kgdb_io_module_registered) {
+ kgdb_io_module_registered = 1;
+ kgdb_arch_init();
+ atomic_notifier_chain_register(&panic_notifier_list,
+ &kgdb_panic_notifier);
+ register_module_notifier(&kgdb_module_load_nb);
+ register_reboot_notifier(&kgdb_reboot_notifier);
+#ifdef CONFIG_MAGIC_SYSRQ
+ register_sysrq_key('g', &sysrq_gdb_op);
+#endif
+#ifdef CONFIG_KGDB_CONSOLE_OUTPUT
+ /* Initialize the console registration */
+ register_console(&kgdbcons);
+#endif
+ }
+}
+
+static void kgdb_unregister_callbacks(void)
+{
+ /*
+ * When this routine is called KGDB should unregister from the
+ * panic handler and clean up, making sure it is not handling any
+ * break exceptions at the time.
+ */
+ if (kgdb_io_module_registered) {
+ kgdb_io_module_registered = 0;
+ kgdb_arch_uninit();
+ atomic_notifier_chain_unregister(&panic_notifier_list,
+ &kgdb_panic_notifier);
+ unregister_module_notifier(&kgdb_module_load_nb);
+ unregister_reboot_notifier(&kgdb_reboot_notifier);
+#ifdef CONFIG_MAGIC_SYSRQ
+ unregister_sysrq_key('g', &sysrq_gdb_op);
+#endif
+#ifdef CONFIG_KGDB_CONSOLE_OUTPUT
+ /* Initialize the console registration */
+ unregister_console(&kgdbcons);
+#endif
+ }
+}
+
+static void kgdb_initial_breakpoint(void)
+{
+ kgdb_break_asap = 0;
+
+ printk(KERN_CRIT "kgdb: Waiting for connection from remote gdb...\n");
+ kgdb_breakpoint();
+}
+
+int kgdb_register_io_module(struct kgdb_io *new_kgdb_io_ops)
+{
+ int err;
+
+ spin_lock(&kgdb_registration_lock);
+
+ if (kgdb_io_ops) {
+ spin_unlock(&kgdb_registration_lock);
+
+ printk(KERN_ERR "kgdb: Another I/O driver is already "
+ "registered with KGDB.\n");
+ return -EBUSY;
+ }
+
+ if (new_kgdb_io_ops->init) {
+ err = new_kgdb_io_ops->init();
+ if (err) {
+ spin_unlock(&kgdb_registration_lock);
+ return err;
+ }
+ }
+
+ kgdb_io_ops = new_kgdb_io_ops;
+
+ spin_unlock(&kgdb_registration_lock);
+
+ printk(KERN_INFO "kgdb: Registered I/O driver %s.\n",
+ new_kgdb_io_ops->name);
+
+ /* Arm KGDB now. */
+ kgdb_register_callbacks();
+
+ if (kgdb_break_asap)
+ kgdb_initial_breakpoint();
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(kgdb_register_io_module);
+
+void kgdb_unregister_io_module(struct kgdb_io *old_kgdb_io_ops)
+{
+ BUG_ON(kgdb_connected);
+
+ /*
+ * KGDB is no longer able to communicate out, so
+ * unregister our callbacks and reset state.
+ */
+ kgdb_unregister_callbacks();
+
+ spin_lock(&kgdb_registration_lock);
+
+ WARN_ON_ONCE(kgdb_io_ops != old_kgdb_io_ops);
+ kgdb_io_ops = NULL;
+
+ spin_unlock(&kgdb_registration_lock);
+
+ printk(KERN_INFO
+ "kgdb: Unregistered I/O driver %s, debugger disabled.\n",
+ old_kgdb_io_ops->name);
+}
+EXPORT_SYMBOL_GPL(kgdb_unregister_io_module);
+
+/*
+ * This function will generate a breakpoint exception. It is used at the
+ * beginning of a program to sync up with a debugger and can be used
+ * otherwise as a quick means to stop program execution and "break" into
+ * the debugger.
+ */
+void kgdb_breakpoint(void)
+{
+ atomic_set(&kgdb_setting_breakpoint, 1);
+ wmb(); /* Sync point before breakpoint */
+ arch_kgdb_breakpoint();
+ wmb(); /* Sync point after breakpoint */
+ atomic_set(&kgdb_setting_breakpoint, 0);
+}
+EXPORT_SYMBOL_GPL(kgdb_breakpoint);
+
+static int
+kgdb_notify_reboot(struct notifier_block *this, unsigned long code, void *x)
+{
+ unsigned long flags;
+
+ /*
+ * If we're debugging, or KGDB has not connected, don't try
+ * and print:
+ */
+ if (!kgdb_connected || atomic_read(&debugger_active) != 0)
+ return 0;
+
+ if (code == SYS_RESTART || code == SYS_HALT || code == SYS_POWER_OFF) {
+ local_irq_save(flags);
+ put_packet("X00");
+ kgdb_connected = 0;
+ local_irq_restore(flags);
+ }
+ return NOTIFY_DONE;
+}
+
+static int __init opt_kgdb_wait(char *str)
+{
+ kgdb_break_asap = 1;
+
+ if (kgdb_io_module_registered)
+ kgdb_initial_breakpoint();
+
+ return 0;
+}
+
+early_param("kgdbwait", opt_kgdb_wait);
Index: linux-kgdb.q/lib/Kconfig.debug
===================================================================
--- linux-kgdb.q.orig/lib/Kconfig.debug
+++ linux-kgdb.q/lib/Kconfig.debug
@@ -632,3 +632,5 @@ config PROVIDE_OHCI1394_DMA_INIT
See Documentation/debugging-via-ohci1394.txt for more information.
source "samples/Kconfig"
+
+source "lib/Kconfig.kgdb"
Index: linux-kgdb.q/lib/Kconfig.kgdb
===================================================================
--- /dev/null
+++ linux-kgdb.q/lib/Kconfig.kgdb
@@ -0,0 +1,37 @@
+
+menuconfig KGDB
+ bool "KGDB: kernel debugging with remote gdb"
+ select FRAME_POINTER
+ depends on ARCH_SUPPORTS_KGDB
+ depends on DEBUG_KERNEL && EXPERIMENTAL
+ help
+ If you say Y here, it will be possible to remotely debug the
+ kernel using gdb. Documentation of kernel debugger is available
+ at http://kgdb.sourceforge.net as well as in DocBook form
+ in Documentation/DocBook/. If unsure, say N.
+
+config KGDB_ARCH_HAS_SHADOW_INFO
+ bool
+
+config KGDB_CONSOLE_OUTPUT
+ 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.
+ Note that if you use this in conjunction with KGDBOE, if the
+ ethernet driver runs into an error condition during use with KGDB,
+ it is possible to hit an infinite recursion, causing the kernel
+ to crash, and typically reboot. For this reason, it is preferable
+ to use NETCONSOLE in conjunction with KGDBOE instead of
+ KGDB_CONSOLE.
+
+config KGDBOC
+ tristate "KGDB: use kgdb over the serial console"
+ depends on KGDB
+ select CONSOLE_POLL
+ select MAGIC_SYSRQ
+ default y
+ help
+ Share a serial console with kgdb. Sysrq-g must be used
+ to break in initially.
--
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