d7161a6534
On the x86 arch, user space single step exceptions should be ignored if they occur in the kernel space, such as ptrace stepping through a system call. First check if it is kgdb that is executing a single step, then ensure it is not an accidental traversal into the user space, while in kgdb, any other time the TIF_SINGLESTEP is set, kgdb should ignore the exception. On x86, arm, mips and powerpc, the kgdb_contthread usage was inconsistent with the way single stepping is implemented in the kgdb core. The arch specific stub should always set the kgdb_cpu_doing_single_step correctly if it is single stepping. This allows kgdb to correctly process an instruction steps if ptrace happens to be requesting an instruction step over a system call. Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
1733 lines
38 KiB
C
1733 lines
38 KiB
C
/*
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* KGDB stub.
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*
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* Maintainer: Jason Wessel <jason.wessel@windriver.com>
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*
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* Copyright (C) 2000-2001 VERITAS Software Corporation.
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* Copyright (C) 2002-2004 Timesys Corporation
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* Copyright (C) 2003-2004 Amit S. Kale <amitkale@linsyssoft.com>
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* Copyright (C) 2004 Pavel Machek <pavel@suse.cz>
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* Copyright (C) 2004-2006 Tom Rini <trini@kernel.crashing.org>
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* Copyright (C) 2004-2006 LinSysSoft Technologies Pvt. Ltd.
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* Copyright (C) 2005-2008 Wind River Systems, Inc.
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* Copyright (C) 2007 MontaVista Software, Inc.
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* Copyright (C) 2008 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
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*
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* Contributors at various stages not listed above:
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* Jason Wessel ( jason.wessel@windriver.com )
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* George Anzinger <george@mvista.com>
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* Anurekh Saxena (anurekh.saxena@timesys.com)
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* Lake Stevens Instrument Division (Glenn Engel)
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* Jim Kingdon, Cygnus Support.
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*
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* Original KGDB stub: David Grothe <dave@gcom.com>,
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* Tigran Aivazian <tigran@sco.com>
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*
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* This file is licensed under the terms of the GNU General Public License
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* version 2. This program is licensed "as is" without any warranty of any
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* kind, whether express or implied.
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*/
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#include <linux/pid_namespace.h>
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#include <linux/clocksource.h>
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#include <linux/interrupt.h>
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#include <linux/spinlock.h>
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#include <linux/console.h>
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#include <linux/threads.h>
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#include <linux/uaccess.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/ptrace.h>
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#include <linux/reboot.h>
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#include <linux/string.h>
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#include <linux/delay.h>
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#include <linux/sched.h>
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#include <linux/sysrq.h>
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#include <linux/init.h>
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#include <linux/kgdb.h>
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#include <linux/pid.h>
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#include <linux/smp.h>
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#include <linux/mm.h>
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#include <asm/cacheflush.h>
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#include <asm/byteorder.h>
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#include <asm/atomic.h>
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#include <asm/system.h>
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#include <asm/unaligned.h>
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static int kgdb_break_asap;
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#define KGDB_MAX_THREAD_QUERY 17
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struct kgdb_state {
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int ex_vector;
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int signo;
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int err_code;
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int cpu;
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int pass_exception;
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unsigned long thr_query;
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unsigned long threadid;
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long kgdb_usethreadid;
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struct pt_regs *linux_regs;
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};
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static struct debuggerinfo_struct {
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void *debuggerinfo;
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struct task_struct *task;
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} kgdb_info[NR_CPUS];
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/**
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* kgdb_connected - Is a host GDB connected to us?
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*/
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int kgdb_connected;
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EXPORT_SYMBOL_GPL(kgdb_connected);
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/* All the KGDB handlers are installed */
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static int kgdb_io_module_registered;
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/* Guard for recursive entry */
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static int exception_level;
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static struct kgdb_io *kgdb_io_ops;
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static DEFINE_SPINLOCK(kgdb_registration_lock);
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/* kgdb console driver is loaded */
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static int kgdb_con_registered;
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/* determine if kgdb console output should be used */
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static int kgdb_use_con;
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static int __init opt_kgdb_con(char *str)
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{
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kgdb_use_con = 1;
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return 0;
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}
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early_param("kgdbcon", opt_kgdb_con);
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module_param(kgdb_use_con, int, 0644);
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/*
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* Holds information about breakpoints in a kernel. These breakpoints are
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* added and removed by gdb.
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*/
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static struct kgdb_bkpt kgdb_break[KGDB_MAX_BREAKPOINTS] = {
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[0 ... KGDB_MAX_BREAKPOINTS-1] = { .state = BP_UNDEFINED }
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};
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/*
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* The CPU# of the active CPU, or -1 if none:
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*/
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atomic_t kgdb_active = ATOMIC_INIT(-1);
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/*
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* We use NR_CPUs not PERCPU, in case kgdb is used to debug early
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* bootup code (which might not have percpu set up yet):
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*/
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static atomic_t passive_cpu_wait[NR_CPUS];
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static atomic_t cpu_in_kgdb[NR_CPUS];
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atomic_t kgdb_setting_breakpoint;
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struct task_struct *kgdb_usethread;
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struct task_struct *kgdb_contthread;
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int kgdb_single_step;
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/* Our I/O buffers. */
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static char remcom_in_buffer[BUFMAX];
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static char remcom_out_buffer[BUFMAX];
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/* Storage for the registers, in GDB format. */
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static unsigned long gdb_regs[(NUMREGBYTES +
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sizeof(unsigned long) - 1) /
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sizeof(unsigned long)];
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/* to keep track of the CPU which is doing the single stepping*/
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atomic_t kgdb_cpu_doing_single_step = ATOMIC_INIT(-1);
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/*
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* If you are debugging a problem where roundup (the collection of
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* all other CPUs) is a problem [this should be extremely rare],
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* then use the nokgdbroundup option to avoid roundup. In that case
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* the other CPUs might interfere with your debugging context, so
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* use this with care:
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*/
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static int kgdb_do_roundup = 1;
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static int __init opt_nokgdbroundup(char *str)
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{
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kgdb_do_roundup = 0;
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return 0;
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}
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early_param("nokgdbroundup", opt_nokgdbroundup);
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/*
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* Finally, some KGDB code :-)
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*/
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/*
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* Weak aliases for breakpoint management,
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* can be overriden by architectures when needed:
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*/
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int __weak kgdb_arch_set_breakpoint(unsigned long addr, char *saved_instr)
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{
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int err;
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err = probe_kernel_read(saved_instr, (char *)addr, BREAK_INSTR_SIZE);
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if (err)
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return err;
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return probe_kernel_write((char *)addr, arch_kgdb_ops.gdb_bpt_instr,
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BREAK_INSTR_SIZE);
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}
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int __weak kgdb_arch_remove_breakpoint(unsigned long addr, char *bundle)
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{
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return probe_kernel_write((char *)addr,
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(char *)bundle, BREAK_INSTR_SIZE);
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}
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int __weak kgdb_validate_break_address(unsigned long addr)
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{
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char tmp_variable[BREAK_INSTR_SIZE];
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int err;
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/* Validate setting the breakpoint and then removing it. In the
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* remove fails, the kernel needs to emit a bad message because we
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* are deep trouble not being able to put things back the way we
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* found them.
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*/
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err = kgdb_arch_set_breakpoint(addr, tmp_variable);
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if (err)
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return err;
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err = kgdb_arch_remove_breakpoint(addr, tmp_variable);
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if (err)
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printk(KERN_ERR "KGDB: Critical breakpoint error, kernel "
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"memory destroyed at: %lx", addr);
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return err;
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}
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unsigned long __weak kgdb_arch_pc(int exception, struct pt_regs *regs)
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{
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return instruction_pointer(regs);
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}
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int __weak kgdb_arch_init(void)
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{
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return 0;
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}
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int __weak kgdb_skipexception(int exception, struct pt_regs *regs)
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{
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return 0;
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}
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void __weak
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kgdb_post_primary_code(struct pt_regs *regs, int e_vector, int err_code)
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{
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return;
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}
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/**
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* kgdb_disable_hw_debug - Disable hardware debugging while we in kgdb.
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* @regs: Current &struct pt_regs.
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*
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* This function will be called if the particular architecture must
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* disable hardware debugging while it is processing gdb packets or
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* handling exception.
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*/
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void __weak kgdb_disable_hw_debug(struct pt_regs *regs)
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{
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}
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/*
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* GDB remote protocol parser:
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*/
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static int hex(char ch)
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{
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if ((ch >= 'a') && (ch <= 'f'))
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return ch - 'a' + 10;
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if ((ch >= '0') && (ch <= '9'))
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return ch - '0';
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if ((ch >= 'A') && (ch <= 'F'))
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return ch - 'A' + 10;
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return -1;
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}
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/* scan for the sequence $<data>#<checksum> */
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static void get_packet(char *buffer)
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{
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unsigned char checksum;
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unsigned char xmitcsum;
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int count;
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char ch;
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do {
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/*
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* Spin and wait around for the start character, ignore all
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* other characters:
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*/
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while ((ch = (kgdb_io_ops->read_char())) != '$')
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/* nothing */;
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kgdb_connected = 1;
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checksum = 0;
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xmitcsum = -1;
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count = 0;
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/*
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* now, read until a # or end of buffer is found:
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*/
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while (count < (BUFMAX - 1)) {
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ch = kgdb_io_ops->read_char();
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if (ch == '#')
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break;
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checksum = checksum + ch;
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buffer[count] = ch;
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count = count + 1;
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}
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buffer[count] = 0;
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if (ch == '#') {
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xmitcsum = hex(kgdb_io_ops->read_char()) << 4;
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xmitcsum += hex(kgdb_io_ops->read_char());
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if (checksum != xmitcsum)
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/* failed checksum */
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kgdb_io_ops->write_char('-');
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else
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/* successful transfer */
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kgdb_io_ops->write_char('+');
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if (kgdb_io_ops->flush)
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kgdb_io_ops->flush();
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}
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} while (checksum != xmitcsum);
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}
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/*
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* Send the packet in buffer.
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* Check for gdb connection if asked for.
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*/
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static void put_packet(char *buffer)
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{
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unsigned char checksum;
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int count;
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char ch;
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/*
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* $<packet info>#<checksum>.
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*/
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while (1) {
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kgdb_io_ops->write_char('$');
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checksum = 0;
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count = 0;
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while ((ch = buffer[count])) {
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kgdb_io_ops->write_char(ch);
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checksum += ch;
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count++;
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}
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kgdb_io_ops->write_char('#');
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kgdb_io_ops->write_char(hex_asc_hi(checksum));
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kgdb_io_ops->write_char(hex_asc_lo(checksum));
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if (kgdb_io_ops->flush)
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kgdb_io_ops->flush();
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/* Now see what we get in reply. */
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ch = kgdb_io_ops->read_char();
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if (ch == 3)
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ch = kgdb_io_ops->read_char();
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/* If we get an ACK, we are done. */
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if (ch == '+')
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return;
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/*
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* If we get the start of another packet, this means
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* that GDB is attempting to reconnect. We will NAK
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* the packet being sent, and stop trying to send this
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* packet.
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*/
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if (ch == '$') {
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kgdb_io_ops->write_char('-');
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if (kgdb_io_ops->flush)
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kgdb_io_ops->flush();
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return;
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}
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}
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}
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/*
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* Convert the memory pointed to by mem into hex, placing result in buf.
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* Return a pointer to the last char put in buf (null). May return an error.
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*/
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int kgdb_mem2hex(char *mem, char *buf, int count)
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{
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char *tmp;
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int err;
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/*
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* We use the upper half of buf as an intermediate buffer for the
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* raw memory copy. Hex conversion will work against this one.
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*/
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tmp = buf + count;
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err = probe_kernel_read(tmp, mem, count);
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if (!err) {
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while (count > 0) {
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buf = pack_hex_byte(buf, *tmp);
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tmp++;
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count--;
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}
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*buf = 0;
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}
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return err;
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}
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/*
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* Copy the binary array pointed to by buf into mem. Fix $, #, and
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* 0x7d escaped with 0x7d. Return a pointer to the character after
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* the last byte written.
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*/
|
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static int kgdb_ebin2mem(char *buf, char *mem, int count)
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{
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int err = 0;
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char c;
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while (count-- > 0) {
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c = *buf++;
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if (c == 0x7d)
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c = *buf++ ^ 0x20;
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err = probe_kernel_write(mem, &c, 1);
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if (err)
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break;
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mem++;
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}
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return err;
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}
|
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|
|
/*
|
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* Convert the hex array pointed to by buf into binary to be placed in mem.
|
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* Return a pointer to the character AFTER the last byte written.
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* May return an error.
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*/
|
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int kgdb_hex2mem(char *buf, char *mem, int count)
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{
|
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char *tmp_raw;
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char *tmp_hex;
|
|
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/*
|
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* We use the upper half of buf as an intermediate buffer for the
|
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* raw memory that is converted from hex.
|
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*/
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tmp_raw = buf + count * 2;
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tmp_hex = tmp_raw - 1;
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while (tmp_hex >= buf) {
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tmp_raw--;
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*tmp_raw = hex(*tmp_hex--);
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*tmp_raw |= hex(*tmp_hex--) << 4;
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}
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return probe_kernel_write(mem, tmp_raw, count);
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}
|
|
|
|
/*
|
|
* While we find nice hex chars, build a long_val.
|
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* Return number of chars processed.
|
|
*/
|
|
int kgdb_hex2long(char **ptr, unsigned long *long_val)
|
|
{
|
|
int hex_val;
|
|
int num = 0;
|
|
int negate = 0;
|
|
|
|
*long_val = 0;
|
|
|
|
if (**ptr == '-') {
|
|
negate = 1;
|
|
(*ptr)++;
|
|
}
|
|
while (**ptr) {
|
|
hex_val = hex(**ptr);
|
|
if (hex_val < 0)
|
|
break;
|
|
|
|
*long_val = (*long_val << 4) | hex_val;
|
|
num++;
|
|
(*ptr)++;
|
|
}
|
|
|
|
if (negate)
|
|
*long_val = -*long_val;
|
|
|
|
return num;
|
|
}
|
|
|
|
/* Write memory due to an 'M' or 'X' packet. */
|
|
static int write_mem_msg(int binary)
|
|
{
|
|
char *ptr = &remcom_in_buffer[1];
|
|
unsigned long addr;
|
|
unsigned long length;
|
|
int err;
|
|
|
|
if (kgdb_hex2long(&ptr, &addr) > 0 && *(ptr++) == ',' &&
|
|
kgdb_hex2long(&ptr, &length) > 0 && *(ptr++) == ':') {
|
|
if (binary)
|
|
err = kgdb_ebin2mem(ptr, (char *)addr, length);
|
|
else
|
|
err = kgdb_hex2mem(ptr, (char *)addr, length);
|
|
if (err)
|
|
return err;
|
|
if (CACHE_FLUSH_IS_SAFE)
|
|
flush_icache_range(addr, addr + length);
|
|
return 0;
|
|
}
|
|
|
|
return -EINVAL;
|
|
}
|
|
|
|
static void error_packet(char *pkt, int error)
|
|
{
|
|
error = -error;
|
|
pkt[0] = 'E';
|
|
pkt[1] = hex_asc[(error / 10)];
|
|
pkt[2] = hex_asc[(error % 10)];
|
|
pkt[3] = '\0';
|
|
}
|
|
|
|
/*
|
|
* Thread ID accessors. We represent a flat TID space to GDB, where
|
|
* the per CPU idle threads (which under Linux all have PID 0) are
|
|
* remapped to negative TIDs.
|
|
*/
|
|
|
|
#define BUF_THREAD_ID_SIZE 16
|
|
|
|
static char *pack_threadid(char *pkt, unsigned char *id)
|
|
{
|
|
char *limit;
|
|
|
|
limit = pkt + BUF_THREAD_ID_SIZE;
|
|
while (pkt < limit)
|
|
pkt = pack_hex_byte(pkt, *id++);
|
|
|
|
return pkt;
|
|
}
|
|
|
|
static void int_to_threadref(unsigned char *id, int value)
|
|
{
|
|
unsigned char *scan;
|
|
int i = 4;
|
|
|
|
scan = (unsigned char *)id;
|
|
while (i--)
|
|
*scan++ = 0;
|
|
put_unaligned_be32(value, scan);
|
|
}
|
|
|
|
static struct task_struct *getthread(struct pt_regs *regs, int tid)
|
|
{
|
|
/*
|
|
* Non-positive TIDs are remapped to the cpu shadow information
|
|
*/
|
|
if (tid == 0 || tid == -1)
|
|
tid = -atomic_read(&kgdb_active) - 2;
|
|
if (tid < 0) {
|
|
if (kgdb_info[-tid - 2].task)
|
|
return kgdb_info[-tid - 2].task;
|
|
else
|
|
return idle_task(-tid - 2);
|
|
}
|
|
|
|
/*
|
|
* find_task_by_pid_ns() 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_ns(tid, &init_pid_ns);
|
|
}
|
|
|
|
/*
|
|
* CPU debug state control:
|
|
*/
|
|
|
|
#ifdef CONFIG_SMP
|
|
static void kgdb_wait(struct pt_regs *regs)
|
|
{
|
|
unsigned long flags;
|
|
int cpu;
|
|
|
|
local_irq_save(flags);
|
|
cpu = raw_smp_processor_id();
|
|
kgdb_info[cpu].debuggerinfo = regs;
|
|
kgdb_info[cpu].task = current;
|
|
/*
|
|
* Make sure the above info reaches the primary CPU before
|
|
* our cpu_in_kgdb[] flag setting does:
|
|
*/
|
|
smp_wmb();
|
|
atomic_set(&cpu_in_kgdb[cpu], 1);
|
|
|
|
/* Wait till primary CPU is done with debugging */
|
|
while (atomic_read(&passive_cpu_wait[cpu]))
|
|
cpu_relax();
|
|
|
|
kgdb_info[cpu].debuggerinfo = NULL;
|
|
kgdb_info[cpu].task = NULL;
|
|
|
|
/* fix up hardware debug registers on local cpu */
|
|
if (arch_kgdb_ops.correct_hw_break)
|
|
arch_kgdb_ops.correct_hw_break();
|
|
|
|
/* Signal the primary CPU that we are done: */
|
|
atomic_set(&cpu_in_kgdb[cpu], 0);
|
|
clocksource_touch_watchdog();
|
|
local_irq_restore(flags);
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* Some architectures need cache flushes when we set/clear a
|
|
* breakpoint:
|
|
*/
|
|
static void kgdb_flush_swbreak_addr(unsigned long addr)
|
|
{
|
|
if (!CACHE_FLUSH_IS_SAFE)
|
|
return;
|
|
|
|
if (current->mm && current->mm->mmap_cache) {
|
|
flush_cache_range(current->mm->mmap_cache,
|
|
addr, addr + BREAK_INSTR_SIZE);
|
|
}
|
|
/* Force flush instruction cache if it was outside the mm */
|
|
flush_icache_range(addr, addr + BREAK_INSTR_SIZE);
|
|
}
|
|
|
|
/*
|
|
* SW breakpoint management:
|
|
*/
|
|
static int kgdb_activate_sw_breakpoints(void)
|
|
{
|
|
unsigned long addr;
|
|
int error = 0;
|
|
int i;
|
|
|
|
for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
|
|
if (kgdb_break[i].state != BP_SET)
|
|
continue;
|
|
|
|
addr = kgdb_break[i].bpt_addr;
|
|
error = kgdb_arch_set_breakpoint(addr,
|
|
kgdb_break[i].saved_instr);
|
|
if (error)
|
|
return error;
|
|
|
|
kgdb_flush_swbreak_addr(addr);
|
|
kgdb_break[i].state = BP_ACTIVE;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int kgdb_set_sw_break(unsigned long addr)
|
|
{
|
|
int err = kgdb_validate_break_address(addr);
|
|
int breakno = -1;
|
|
int i;
|
|
|
|
if (err)
|
|
return err;
|
|
|
|
for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
|
|
if ((kgdb_break[i].state == BP_SET) &&
|
|
(kgdb_break[i].bpt_addr == addr))
|
|
return -EEXIST;
|
|
}
|
|
for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
|
|
if (kgdb_break[i].state == BP_REMOVED &&
|
|
kgdb_break[i].bpt_addr == addr) {
|
|
breakno = i;
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (breakno == -1) {
|
|
for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
|
|
if (kgdb_break[i].state == BP_UNDEFINED) {
|
|
breakno = i;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
if (breakno == -1)
|
|
return -E2BIG;
|
|
|
|
kgdb_break[breakno].state = BP_SET;
|
|
kgdb_break[breakno].type = BP_BREAKPOINT;
|
|
kgdb_break[breakno].bpt_addr = addr;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int kgdb_deactivate_sw_breakpoints(void)
|
|
{
|
|
unsigned long addr;
|
|
int error = 0;
|
|
int i;
|
|
|
|
for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
|
|
if (kgdb_break[i].state != BP_ACTIVE)
|
|
continue;
|
|
addr = kgdb_break[i].bpt_addr;
|
|
error = kgdb_arch_remove_breakpoint(addr,
|
|
kgdb_break[i].saved_instr);
|
|
if (error)
|
|
return error;
|
|
|
|
kgdb_flush_swbreak_addr(addr);
|
|
kgdb_break[i].state = BP_SET;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int kgdb_remove_sw_break(unsigned long addr)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
|
|
if ((kgdb_break[i].state == BP_SET) &&
|
|
(kgdb_break[i].bpt_addr == addr)) {
|
|
kgdb_break[i].state = BP_REMOVED;
|
|
return 0;
|
|
}
|
|
}
|
|
return -ENOENT;
|
|
}
|
|
|
|
int kgdb_isremovedbreak(unsigned long addr)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
|
|
if ((kgdb_break[i].state == BP_REMOVED) &&
|
|
(kgdb_break[i].bpt_addr == addr))
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static 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_ACTIVE)
|
|
goto setundefined;
|
|
addr = kgdb_break[i].bpt_addr;
|
|
error = kgdb_arch_remove_breakpoint(addr,
|
|
kgdb_break[i].saved_instr);
|
|
if (error)
|
|
printk(KERN_ERR "KGDB: breakpoint remove failed: %lx\n",
|
|
addr);
|
|
setundefined:
|
|
kgdb_break[i].state = BP_UNDEFINED;
|
|
}
|
|
|
|
/* Clear hardware breakpoints. */
|
|
if (arch_kgdb_ops.remove_all_hw_break)
|
|
arch_kgdb_ops.remove_all_hw_break();
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Remap normal tasks to their real PID,
|
|
* CPU shadow threads are mapped to -CPU - 2
|
|
*/
|
|
static inline int shadow_pid(int realpid)
|
|
{
|
|
if (realpid)
|
|
return realpid;
|
|
|
|
return -raw_smp_processor_id() - 2;
|
|
}
|
|
|
|
static char gdbmsgbuf[BUFMAX + 1];
|
|
|
|
static void kgdb_msg_write(const char *s, int len)
|
|
{
|
|
char *bufptr;
|
|
int wcount;
|
|
int i;
|
|
|
|
/* 'O'utput */
|
|
gdbmsgbuf[0] = 'O';
|
|
|
|
/* Fill and send buffers... */
|
|
while (len > 0) {
|
|
bufptr = gdbmsgbuf + 1;
|
|
|
|
/* Calculate how many this time */
|
|
if ((len << 1) > (BUFMAX - 2))
|
|
wcount = (BUFMAX - 2) >> 1;
|
|
else
|
|
wcount = len;
|
|
|
|
/* Pack in hex chars */
|
|
for (i = 0; i < wcount; i++)
|
|
bufptr = pack_hex_byte(bufptr, s[i]);
|
|
*bufptr = '\0';
|
|
|
|
/* Move up */
|
|
s += wcount;
|
|
len -= wcount;
|
|
|
|
/* Write packet */
|
|
put_packet(gdbmsgbuf);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Return true if there is a valid kgdb I/O module. Also if no
|
|
* debugger is attached a message can be printed to the console about
|
|
* waiting for the debugger to attach.
|
|
*
|
|
* The print_wait argument is only to be true when called from inside
|
|
* the core kgdb_handle_exception, because it will wait for the
|
|
* debugger to attach.
|
|
*/
|
|
static int kgdb_io_ready(int print_wait)
|
|
{
|
|
if (!kgdb_io_ops)
|
|
return 0;
|
|
if (kgdb_connected)
|
|
return 1;
|
|
if (atomic_read(&kgdb_setting_breakpoint))
|
|
return 1;
|
|
if (print_wait)
|
|
printk(KERN_CRIT "KGDB: Waiting for remote debugger\n");
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* All the functions that start with gdb_cmd are the various
|
|
* operations to implement the handlers for the gdbserial protocol
|
|
* where KGDB is communicating with an external debugger
|
|
*/
|
|
|
|
/* Handle the '?' status packets */
|
|
static void gdb_cmd_status(struct kgdb_state *ks)
|
|
{
|
|
/*
|
|
* We know that this packet is only sent
|
|
* during initial connect. So to be safe,
|
|
* we clear out our breakpoints now in case
|
|
* GDB is reconnecting.
|
|
*/
|
|
remove_all_break();
|
|
|
|
remcom_out_buffer[0] = 'S';
|
|
pack_hex_byte(&remcom_out_buffer[1], ks->signo);
|
|
}
|
|
|
|
/* Handle the 'g' get registers request */
|
|
static void gdb_cmd_getregs(struct kgdb_state *ks)
|
|
{
|
|
struct task_struct *thread;
|
|
void *local_debuggerinfo;
|
|
int i;
|
|
|
|
thread = kgdb_usethread;
|
|
if (!thread) {
|
|
thread = kgdb_info[ks->cpu].task;
|
|
local_debuggerinfo = kgdb_info[ks->cpu].debuggerinfo;
|
|
} else {
|
|
local_debuggerinfo = NULL;
|
|
for_each_online_cpu(i) {
|
|
/*
|
|
* Try to find the task on some other
|
|
* or possibly this node if we do not
|
|
* find the matching task then we try
|
|
* to approximate the results.
|
|
*/
|
|
if (thread == kgdb_info[i].task)
|
|
local_debuggerinfo = kgdb_info[i].debuggerinfo;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* All threads that don't have debuggerinfo should be
|
|
* in __schedule() sleeping, since all other CPUs
|
|
* are in kgdb_wait, and thus have debuggerinfo.
|
|
*/
|
|
if (local_debuggerinfo) {
|
|
pt_regs_to_gdb_regs(gdb_regs, local_debuggerinfo);
|
|
} else {
|
|
/*
|
|
* Pull stuff saved during switch_to; nothing
|
|
* else is accessible (or even particularly
|
|
* relevant).
|
|
*
|
|
* This should be enough for a stack trace.
|
|
*/
|
|
sleeping_thread_to_gdb_regs(gdb_regs, thread);
|
|
}
|
|
kgdb_mem2hex((char *)gdb_regs, remcom_out_buffer, NUMREGBYTES);
|
|
}
|
|
|
|
/* Handle the 'G' set registers request */
|
|
static void gdb_cmd_setregs(struct kgdb_state *ks)
|
|
{
|
|
kgdb_hex2mem(&remcom_in_buffer[1], (char *)gdb_regs, NUMREGBYTES);
|
|
|
|
if (kgdb_usethread && kgdb_usethread != current) {
|
|
error_packet(remcom_out_buffer, -EINVAL);
|
|
} else {
|
|
gdb_regs_to_pt_regs(gdb_regs, ks->linux_regs);
|
|
strcpy(remcom_out_buffer, "OK");
|
|
}
|
|
}
|
|
|
|
/* Handle the 'm' memory read bytes */
|
|
static void gdb_cmd_memread(struct kgdb_state *ks)
|
|
{
|
|
char *ptr = &remcom_in_buffer[1];
|
|
unsigned long length;
|
|
unsigned long addr;
|
|
int err;
|
|
|
|
if (kgdb_hex2long(&ptr, &addr) > 0 && *ptr++ == ',' &&
|
|
kgdb_hex2long(&ptr, &length) > 0) {
|
|
err = kgdb_mem2hex((char *)addr, remcom_out_buffer, length);
|
|
if (err)
|
|
error_packet(remcom_out_buffer, err);
|
|
} else {
|
|
error_packet(remcom_out_buffer, -EINVAL);
|
|
}
|
|
}
|
|
|
|
/* Handle the 'M' memory write bytes */
|
|
static void gdb_cmd_memwrite(struct kgdb_state *ks)
|
|
{
|
|
int err = write_mem_msg(0);
|
|
|
|
if (err)
|
|
error_packet(remcom_out_buffer, err);
|
|
else
|
|
strcpy(remcom_out_buffer, "OK");
|
|
}
|
|
|
|
/* Handle the 'X' memory binary write bytes */
|
|
static void gdb_cmd_binwrite(struct kgdb_state *ks)
|
|
{
|
|
int err = write_mem_msg(1);
|
|
|
|
if (err)
|
|
error_packet(remcom_out_buffer, err);
|
|
else
|
|
strcpy(remcom_out_buffer, "OK");
|
|
}
|
|
|
|
/* Handle the 'D' or 'k', detach or kill packets */
|
|
static void gdb_cmd_detachkill(struct kgdb_state *ks)
|
|
{
|
|
int error;
|
|
|
|
/* The detach case */
|
|
if (remcom_in_buffer[0] == 'D') {
|
|
error = remove_all_break();
|
|
if (error < 0) {
|
|
error_packet(remcom_out_buffer, error);
|
|
} else {
|
|
strcpy(remcom_out_buffer, "OK");
|
|
kgdb_connected = 0;
|
|
}
|
|
put_packet(remcom_out_buffer);
|
|
} else {
|
|
/*
|
|
* Assume the kill case, with no exit code checking,
|
|
* trying to force detach the debugger:
|
|
*/
|
|
remove_all_break();
|
|
kgdb_connected = 0;
|
|
}
|
|
}
|
|
|
|
/* Handle the 'R' reboot packets */
|
|
static int gdb_cmd_reboot(struct kgdb_state *ks)
|
|
{
|
|
/* For now, only honor R0 */
|
|
if (strcmp(remcom_in_buffer, "R0") == 0) {
|
|
printk(KERN_CRIT "Executing emergency reboot\n");
|
|
strcpy(remcom_out_buffer, "OK");
|
|
put_packet(remcom_out_buffer);
|
|
|
|
/*
|
|
* Execution should not return from
|
|
* machine_emergency_restart()
|
|
*/
|
|
machine_emergency_restart();
|
|
kgdb_connected = 0;
|
|
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/* Handle the 'q' query packets */
|
|
static void gdb_cmd_query(struct kgdb_state *ks)
|
|
{
|
|
struct task_struct *g;
|
|
struct task_struct *p;
|
|
unsigned char thref[8];
|
|
char *ptr;
|
|
int i;
|
|
int cpu;
|
|
int finished = 0;
|
|
|
|
switch (remcom_in_buffer[1]) {
|
|
case 's':
|
|
case 'f':
|
|
if (memcmp(remcom_in_buffer + 2, "ThreadInfo", 10)) {
|
|
error_packet(remcom_out_buffer, -EINVAL);
|
|
break;
|
|
}
|
|
|
|
i = 0;
|
|
remcom_out_buffer[0] = 'm';
|
|
ptr = remcom_out_buffer + 1;
|
|
if (remcom_in_buffer[1] == 'f') {
|
|
/* Each cpu is a shadow thread */
|
|
for_each_online_cpu(cpu) {
|
|
ks->thr_query = 0;
|
|
int_to_threadref(thref, -cpu - 2);
|
|
pack_threadid(ptr, thref);
|
|
ptr += BUF_THREAD_ID_SIZE;
|
|
*(ptr++) = ',';
|
|
i++;
|
|
}
|
|
}
|
|
|
|
do_each_thread(g, p) {
|
|
if (i >= ks->thr_query && !finished) {
|
|
int_to_threadref(thref, p->pid);
|
|
pack_threadid(ptr, thref);
|
|
ptr += BUF_THREAD_ID_SIZE;
|
|
*(ptr++) = ',';
|
|
ks->thr_query++;
|
|
if (ks->thr_query % KGDB_MAX_THREAD_QUERY == 0)
|
|
finished = 1;
|
|
}
|
|
i++;
|
|
} while_each_thread(g, p);
|
|
|
|
*(--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 ((int)ks->threadid > 0) {
|
|
kgdb_mem2hex(getthread(ks->linux_regs,
|
|
ks->threadid)->comm,
|
|
remcom_out_buffer, 16);
|
|
} else {
|
|
static char tmpstr[23 + BUF_THREAD_ID_SIZE];
|
|
|
|
sprintf(tmpstr, "shadowCPU%d",
|
|
(int)(-ks->threadid - 2));
|
|
kgdb_mem2hex(tmpstr, remcom_out_buffer, strlen(tmpstr));
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
|
|
/* Handle the 'H' task query packets */
|
|
static void gdb_cmd_task(struct kgdb_state *ks)
|
|
{
|
|
struct task_struct *thread;
|
|
char *ptr;
|
|
|
|
switch (remcom_in_buffer[1]) {
|
|
case 'g':
|
|
ptr = &remcom_in_buffer[2];
|
|
kgdb_hex2long(&ptr, &ks->threadid);
|
|
thread = getthread(ks->linux_regs, ks->threadid);
|
|
if (!thread && ks->threadid > 0) {
|
|
error_packet(remcom_out_buffer, -EINVAL);
|
|
break;
|
|
}
|
|
kgdb_usethread = thread;
|
|
ks->kgdb_usethreadid = ks->threadid;
|
|
strcpy(remcom_out_buffer, "OK");
|
|
break;
|
|
case 'c':
|
|
ptr = &remcom_in_buffer[2];
|
|
kgdb_hex2long(&ptr, &ks->threadid);
|
|
if (!ks->threadid) {
|
|
kgdb_contthread = NULL;
|
|
} else {
|
|
thread = getthread(ks->linux_regs, ks->threadid);
|
|
if (!thread && ks->threadid > 0) {
|
|
error_packet(remcom_out_buffer, -EINVAL);
|
|
break;
|
|
}
|
|
kgdb_contthread = thread;
|
|
}
|
|
strcpy(remcom_out_buffer, "OK");
|
|
break;
|
|
}
|
|
}
|
|
|
|
/* Handle the 'T' thread query packets */
|
|
static void gdb_cmd_thread(struct kgdb_state *ks)
|
|
{
|
|
char *ptr = &remcom_in_buffer[1];
|
|
struct task_struct *thread;
|
|
|
|
kgdb_hex2long(&ptr, &ks->threadid);
|
|
thread = getthread(ks->linux_regs, ks->threadid);
|
|
if (thread)
|
|
strcpy(remcom_out_buffer, "OK");
|
|
else
|
|
error_packet(remcom_out_buffer, -EINVAL);
|
|
}
|
|
|
|
/* Handle the 'z' or 'Z' breakpoint remove or set packets */
|
|
static void gdb_cmd_break(struct kgdb_state *ks)
|
|
{
|
|
/*
|
|
* Since GDB-5.3, it's been drafted that '0' is a software
|
|
* breakpoint, '1' is a hardware breakpoint, so let's do that.
|
|
*/
|
|
char *bpt_type = &remcom_in_buffer[1];
|
|
char *ptr = &remcom_in_buffer[2];
|
|
unsigned long addr;
|
|
unsigned long length;
|
|
int error = 0;
|
|
|
|
if (arch_kgdb_ops.set_hw_breakpoint && *bpt_type >= '1') {
|
|
/* Unsupported */
|
|
if (*bpt_type > '4')
|
|
return;
|
|
} else {
|
|
if (*bpt_type != '0' && *bpt_type != '1')
|
|
/* Unsupported. */
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* Test if this is a hardware breakpoint, and
|
|
* if we support it:
|
|
*/
|
|
if (*bpt_type == '1' && !(arch_kgdb_ops.flags & KGDB_HW_BREAKPOINT))
|
|
/* Unsupported. */
|
|
return;
|
|
|
|
if (*(ptr++) != ',') {
|
|
error_packet(remcom_out_buffer, -EINVAL);
|
|
return;
|
|
}
|
|
if (!kgdb_hex2long(&ptr, &addr)) {
|
|
error_packet(remcom_out_buffer, -EINVAL);
|
|
return;
|
|
}
|
|
if (*(ptr++) != ',' ||
|
|
!kgdb_hex2long(&ptr, &length)) {
|
|
error_packet(remcom_out_buffer, -EINVAL);
|
|
return;
|
|
}
|
|
|
|
if (remcom_in_buffer[0] == 'Z' && *bpt_type == '0')
|
|
error = kgdb_set_sw_break(addr);
|
|
else if (remcom_in_buffer[0] == 'z' && *bpt_type == '0')
|
|
error = kgdb_remove_sw_break(addr);
|
|
else if (remcom_in_buffer[0] == 'Z')
|
|
error = arch_kgdb_ops.set_hw_breakpoint(addr,
|
|
(int)length, *bpt_type - '0');
|
|
else if (remcom_in_buffer[0] == 'z')
|
|
error = arch_kgdb_ops.remove_hw_breakpoint(addr,
|
|
(int) length, *bpt_type - '0');
|
|
|
|
if (error == 0)
|
|
strcpy(remcom_out_buffer, "OK");
|
|
else
|
|
error_packet(remcom_out_buffer, error);
|
|
}
|
|
|
|
/* Handle the 'C' signal / exception passing packets */
|
|
static int gdb_cmd_exception_pass(struct kgdb_state *ks)
|
|
{
|
|
/* C09 == pass exception
|
|
* C15 == detach kgdb, pass exception
|
|
*/
|
|
if (remcom_in_buffer[1] == '0' && remcom_in_buffer[2] == '9') {
|
|
|
|
ks->pass_exception = 1;
|
|
remcom_in_buffer[0] = 'c';
|
|
|
|
} else if (remcom_in_buffer[1] == '1' && remcom_in_buffer[2] == '5') {
|
|
|
|
ks->pass_exception = 1;
|
|
remcom_in_buffer[0] = 'D';
|
|
remove_all_break();
|
|
kgdb_connected = 0;
|
|
return 1;
|
|
|
|
} else {
|
|
error_packet(remcom_out_buffer, -EINVAL);
|
|
return 0;
|
|
}
|
|
|
|
/* Indicate fall through */
|
|
return -1;
|
|
}
|
|
|
|
/*
|
|
* This function performs all gdbserial command procesing
|
|
*/
|
|
static int gdb_serial_stub(struct kgdb_state *ks)
|
|
{
|
|
int error = 0;
|
|
int tmp;
|
|
|
|
/* Clear the out buffer. */
|
|
memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer));
|
|
|
|
if (kgdb_connected) {
|
|
unsigned char thref[8];
|
|
char *ptr;
|
|
|
|
/* Reply to host that an exception has occurred */
|
|
ptr = remcom_out_buffer;
|
|
*ptr++ = 'T';
|
|
ptr = pack_hex_byte(ptr, ks->signo);
|
|
ptr += strlen(strcpy(ptr, "thread:"));
|
|
int_to_threadref(thref, shadow_pid(current->pid));
|
|
ptr = pack_threadid(ptr, thref);
|
|
*ptr++ = ';';
|
|
put_packet(remcom_out_buffer);
|
|
}
|
|
|
|
kgdb_usethread = kgdb_info[ks->cpu].task;
|
|
ks->kgdb_usethreadid = shadow_pid(kgdb_info[ks->cpu].task->pid);
|
|
ks->pass_exception = 0;
|
|
|
|
while (1) {
|
|
error = 0;
|
|
|
|
/* Clear the out buffer. */
|
|
memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer));
|
|
|
|
get_packet(remcom_in_buffer);
|
|
|
|
switch (remcom_in_buffer[0]) {
|
|
case '?': /* gdbserial status */
|
|
gdb_cmd_status(ks);
|
|
break;
|
|
case 'g': /* return the value of the CPU registers */
|
|
gdb_cmd_getregs(ks);
|
|
break;
|
|
case 'G': /* set the value of the CPU registers - return OK */
|
|
gdb_cmd_setregs(ks);
|
|
break;
|
|
case 'm': /* mAA..AA,LLLL Read LLLL bytes at address AA..AA */
|
|
gdb_cmd_memread(ks);
|
|
break;
|
|
case 'M': /* MAA..AA,LLLL: Write LLLL bytes at address AA..AA */
|
|
gdb_cmd_memwrite(ks);
|
|
break;
|
|
case 'X': /* XAA..AA,LLLL: Write LLLL bytes at address AA..AA */
|
|
gdb_cmd_binwrite(ks);
|
|
break;
|
|
/* kill or detach. KGDB should treat this like a
|
|
* continue.
|
|
*/
|
|
case 'D': /* Debugger detach */
|
|
case 'k': /* Debugger detach via kill */
|
|
gdb_cmd_detachkill(ks);
|
|
goto default_handle;
|
|
case 'R': /* Reboot */
|
|
if (gdb_cmd_reboot(ks))
|
|
goto default_handle;
|
|
break;
|
|
case 'q': /* query command */
|
|
gdb_cmd_query(ks);
|
|
break;
|
|
case 'H': /* task related */
|
|
gdb_cmd_task(ks);
|
|
break;
|
|
case 'T': /* Query thread status */
|
|
gdb_cmd_thread(ks);
|
|
break;
|
|
case 'z': /* Break point remove */
|
|
case 'Z': /* Break point set */
|
|
gdb_cmd_break(ks);
|
|
break;
|
|
case 'C': /* Exception passing */
|
|
tmp = gdb_cmd_exception_pass(ks);
|
|
if (tmp > 0)
|
|
goto default_handle;
|
|
if (tmp == 0)
|
|
break;
|
|
/* Fall through on tmp < 0 */
|
|
case 'c': /* Continue packet */
|
|
case 's': /* Single step packet */
|
|
if (kgdb_contthread && kgdb_contthread != current) {
|
|
/* Can't switch threads in kgdb */
|
|
error_packet(remcom_out_buffer, -EINVAL);
|
|
break;
|
|
}
|
|
kgdb_activate_sw_breakpoints();
|
|
/* Fall through to default processing */
|
|
default:
|
|
default_handle:
|
|
error = kgdb_arch_handle_exception(ks->ex_vector,
|
|
ks->signo,
|
|
ks->err_code,
|
|
remcom_in_buffer,
|
|
remcom_out_buffer,
|
|
ks->linux_regs);
|
|
/*
|
|
* Leave cmd processing on error, detach,
|
|
* kill, continue, or single step.
|
|
*/
|
|
if (error >= 0 || remcom_in_buffer[0] == 'D' ||
|
|
remcom_in_buffer[0] == 'k') {
|
|
error = 0;
|
|
goto kgdb_exit;
|
|
}
|
|
|
|
}
|
|
|
|
/* reply to the request */
|
|
put_packet(remcom_out_buffer);
|
|
}
|
|
|
|
kgdb_exit:
|
|
if (ks->pass_exception)
|
|
error = 1;
|
|
return error;
|
|
}
|
|
|
|
static int kgdb_reenter_check(struct kgdb_state *ks)
|
|
{
|
|
unsigned long addr;
|
|
|
|
if (atomic_read(&kgdb_active) != raw_smp_processor_id())
|
|
return 0;
|
|
|
|
/* Panic on recursive debugger calls: */
|
|
exception_level++;
|
|
addr = kgdb_arch_pc(ks->ex_vector, ks->linux_regs);
|
|
kgdb_deactivate_sw_breakpoints();
|
|
|
|
/*
|
|
* If the break point removed ok at the place exception
|
|
* occurred, try to recover and print a warning to the end
|
|
* user because the user planted a breakpoint in a place that
|
|
* KGDB needs in order to function.
|
|
*/
|
|
if (kgdb_remove_sw_break(addr) == 0) {
|
|
exception_level = 0;
|
|
kgdb_skipexception(ks->ex_vector, ks->linux_regs);
|
|
kgdb_activate_sw_breakpoints();
|
|
printk(KERN_CRIT "KGDB: re-enter error: breakpoint removed %lx\n",
|
|
addr);
|
|
WARN_ON_ONCE(1);
|
|
|
|
return 1;
|
|
}
|
|
remove_all_break();
|
|
kgdb_skipexception(ks->ex_vector, ks->linux_regs);
|
|
|
|
if (exception_level > 1) {
|
|
dump_stack();
|
|
panic("Recursive entry to debugger");
|
|
}
|
|
|
|
printk(KERN_CRIT "KGDB: re-enter exception: ALL breakpoints killed\n");
|
|
dump_stack();
|
|
panic("Recursive entry to debugger");
|
|
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* kgdb_handle_exception() - main entry point from a kernel exception
|
|
*
|
|
* Locking hierarchy:
|
|
* interface locks, if any (begin_session)
|
|
* kgdb lock (kgdb_active)
|
|
*/
|
|
int
|
|
kgdb_handle_exception(int evector, int signo, int ecode, struct pt_regs *regs)
|
|
{
|
|
struct kgdb_state kgdb_var;
|
|
struct kgdb_state *ks = &kgdb_var;
|
|
unsigned long flags;
|
|
int error = 0;
|
|
int i, cpu;
|
|
|
|
ks->cpu = raw_smp_processor_id();
|
|
ks->ex_vector = evector;
|
|
ks->signo = signo;
|
|
ks->ex_vector = evector;
|
|
ks->err_code = ecode;
|
|
ks->kgdb_usethreadid = 0;
|
|
ks->linux_regs = regs;
|
|
|
|
if (kgdb_reenter_check(ks))
|
|
return 0; /* Ouch, double exception ! */
|
|
|
|
acquirelock:
|
|
/*
|
|
* Interrupts will be restored by the 'trap return' code, except when
|
|
* single stepping.
|
|
*/
|
|
local_irq_save(flags);
|
|
|
|
cpu = raw_smp_processor_id();
|
|
|
|
/*
|
|
* Acquire the kgdb_active lock:
|
|
*/
|
|
while (atomic_cmpxchg(&kgdb_active, -1, cpu) != -1)
|
|
cpu_relax();
|
|
|
|
/*
|
|
* Do not start the debugger connection on this CPU if the last
|
|
* instance of the exception handler wanted to come into the
|
|
* debugger on a different CPU via a single step
|
|
*/
|
|
if (atomic_read(&kgdb_cpu_doing_single_step) != -1 &&
|
|
atomic_read(&kgdb_cpu_doing_single_step) != cpu) {
|
|
|
|
atomic_set(&kgdb_active, -1);
|
|
clocksource_touch_watchdog();
|
|
local_irq_restore(flags);
|
|
|
|
goto acquirelock;
|
|
}
|
|
|
|
if (!kgdb_io_ready(1)) {
|
|
error = 1;
|
|
goto kgdb_restore; /* No I/O connection, so resume the system */
|
|
}
|
|
|
|
/*
|
|
* Don't enter if we have hit a removed breakpoint.
|
|
*/
|
|
if (kgdb_skipexception(ks->ex_vector, ks->linux_regs))
|
|
goto kgdb_restore;
|
|
|
|
/* Call the I/O driver's pre_exception routine */
|
|
if (kgdb_io_ops->pre_exception)
|
|
kgdb_io_ops->pre_exception();
|
|
|
|
kgdb_info[ks->cpu].debuggerinfo = ks->linux_regs;
|
|
kgdb_info[ks->cpu].task = current;
|
|
|
|
kgdb_disable_hw_debug(ks->linux_regs);
|
|
|
|
/*
|
|
* Get the passive CPU lock which will hold all the non-primary
|
|
* CPU in a spin state while the debugger is active
|
|
*/
|
|
if (!kgdb_single_step) {
|
|
for (i = 0; i < NR_CPUS; i++)
|
|
atomic_set(&passive_cpu_wait[i], 1);
|
|
}
|
|
|
|
/*
|
|
* spin_lock code is good enough as a barrier so we don't
|
|
* need one here:
|
|
*/
|
|
atomic_set(&cpu_in_kgdb[ks->cpu], 1);
|
|
|
|
#ifdef CONFIG_SMP
|
|
/* Signal the other CPUs to enter kgdb_wait() */
|
|
if ((!kgdb_single_step) && kgdb_do_roundup)
|
|
kgdb_roundup_cpus(flags);
|
|
#endif
|
|
|
|
/*
|
|
* Wait for the other CPUs to be notified and be waiting for us:
|
|
*/
|
|
for_each_online_cpu(i) {
|
|
while (!atomic_read(&cpu_in_kgdb[i]))
|
|
cpu_relax();
|
|
}
|
|
|
|
/*
|
|
* At this point the primary processor is completely
|
|
* in the debugger and all secondary CPUs are quiescent
|
|
*/
|
|
kgdb_post_primary_code(ks->linux_regs, ks->ex_vector, ks->err_code);
|
|
kgdb_deactivate_sw_breakpoints();
|
|
kgdb_single_step = 0;
|
|
kgdb_contthread = current;
|
|
exception_level = 0;
|
|
|
|
/* Talk to debugger with gdbserial protocol */
|
|
error = gdb_serial_stub(ks);
|
|
|
|
/* Call the I/O driver's post_exception routine */
|
|
if (kgdb_io_ops->post_exception)
|
|
kgdb_io_ops->post_exception();
|
|
|
|
kgdb_info[ks->cpu].debuggerinfo = NULL;
|
|
kgdb_info[ks->cpu].task = NULL;
|
|
atomic_set(&cpu_in_kgdb[ks->cpu], 0);
|
|
|
|
if (!kgdb_single_step) {
|
|
for (i = NR_CPUS-1; i >= 0; i--)
|
|
atomic_set(&passive_cpu_wait[i], 0);
|
|
/*
|
|
* Wait till all the CPUs have quit
|
|
* from the debugger.
|
|
*/
|
|
for_each_online_cpu(i) {
|
|
while (atomic_read(&cpu_in_kgdb[i]))
|
|
cpu_relax();
|
|
}
|
|
}
|
|
|
|
kgdb_restore:
|
|
/* Free kgdb_active */
|
|
atomic_set(&kgdb_active, -1);
|
|
clocksource_touch_watchdog();
|
|
local_irq_restore(flags);
|
|
|
|
return error;
|
|
}
|
|
|
|
int kgdb_nmicallback(int cpu, void *regs)
|
|
{
|
|
#ifdef CONFIG_SMP
|
|
if (!atomic_read(&cpu_in_kgdb[cpu]) &&
|
|
atomic_read(&kgdb_active) != cpu &&
|
|
atomic_read(&cpu_in_kgdb[atomic_read(&kgdb_active)])) {
|
|
kgdb_wait((struct pt_regs *)regs);
|
|
return 0;
|
|
}
|
|
#endif
|
|
return 1;
|
|
}
|
|
|
|
static void kgdb_console_write(struct console *co, const char *s,
|
|
unsigned count)
|
|
{
|
|
unsigned long flags;
|
|
|
|
/* If we're debugging, or KGDB has not connected, don't try
|
|
* and print. */
|
|
if (!kgdb_connected || atomic_read(&kgdb_active) != -1)
|
|
return;
|
|
|
|
local_irq_save(flags);
|
|
kgdb_msg_write(s, count);
|
|
local_irq_restore(flags);
|
|
}
|
|
|
|
static struct console kgdbcons = {
|
|
.name = "kgdb",
|
|
.write = kgdb_console_write,
|
|
.flags = CON_PRINTBUFFER | CON_ENABLED,
|
|
.index = -1,
|
|
};
|
|
|
|
#ifdef CONFIG_MAGIC_SYSRQ
|
|
static void sysrq_handle_gdb(int key, struct tty_struct *tty)
|
|
{
|
|
if (!kgdb_io_ops) {
|
|
printk(KERN_CRIT "ERROR: No KGDB I/O module available\n");
|
|
return;
|
|
}
|
|
if (!kgdb_connected)
|
|
printk(KERN_CRIT "Entering KGDB\n");
|
|
|
|
kgdb_breakpoint();
|
|
}
|
|
|
|
static struct sysrq_key_op sysrq_gdb_op = {
|
|
.handler = sysrq_handle_gdb,
|
|
.help_msg = "Gdb",
|
|
.action_msg = "GDB",
|
|
};
|
|
#endif
|
|
|
|
static void kgdb_register_callbacks(void)
|
|
{
|
|
if (!kgdb_io_module_registered) {
|
|
kgdb_io_module_registered = 1;
|
|
kgdb_arch_init();
|
|
#ifdef CONFIG_MAGIC_SYSRQ
|
|
register_sysrq_key('g', &sysrq_gdb_op);
|
|
#endif
|
|
if (kgdb_use_con && !kgdb_con_registered) {
|
|
register_console(&kgdbcons);
|
|
kgdb_con_registered = 1;
|
|
}
|
|
}
|
|
}
|
|
|
|
static void kgdb_unregister_callbacks(void)
|
|
{
|
|
/*
|
|
* When this routine is called KGDB should unregister from the
|
|
* panic handler and clean up, making sure it is not handling any
|
|
* break exceptions at the time.
|
|
*/
|
|
if (kgdb_io_module_registered) {
|
|
kgdb_io_module_registered = 0;
|
|
kgdb_arch_exit();
|
|
#ifdef CONFIG_MAGIC_SYSRQ
|
|
unregister_sysrq_key('g', &sysrq_gdb_op);
|
|
#endif
|
|
if (kgdb_con_registered) {
|
|
unregister_console(&kgdbcons);
|
|
kgdb_con_registered = 0;
|
|
}
|
|
}
|
|
}
|
|
|
|
static void kgdb_initial_breakpoint(void)
|
|
{
|
|
kgdb_break_asap = 0;
|
|
|
|
printk(KERN_CRIT "kgdb: Waiting for connection from remote gdb...\n");
|
|
kgdb_breakpoint();
|
|
}
|
|
|
|
/**
|
|
* kgdb_register_io_module - register KGDB IO module
|
|
* @new_kgdb_io_ops: the io ops vector
|
|
*
|
|
* Register it with the KGDB core.
|
|
*/
|
|
int kgdb_register_io_module(struct kgdb_io *new_kgdb_io_ops)
|
|
{
|
|
int err;
|
|
|
|
spin_lock(&kgdb_registration_lock);
|
|
|
|
if (kgdb_io_ops) {
|
|
spin_unlock(&kgdb_registration_lock);
|
|
|
|
printk(KERN_ERR "kgdb: Another I/O driver is already "
|
|
"registered with KGDB.\n");
|
|
return -EBUSY;
|
|
}
|
|
|
|
if (new_kgdb_io_ops->init) {
|
|
err = new_kgdb_io_ops->init();
|
|
if (err) {
|
|
spin_unlock(&kgdb_registration_lock);
|
|
return err;
|
|
}
|
|
}
|
|
|
|
kgdb_io_ops = new_kgdb_io_ops;
|
|
|
|
spin_unlock(&kgdb_registration_lock);
|
|
|
|
printk(KERN_INFO "kgdb: Registered I/O driver %s.\n",
|
|
new_kgdb_io_ops->name);
|
|
|
|
/* Arm KGDB now. */
|
|
kgdb_register_callbacks();
|
|
|
|
if (kgdb_break_asap)
|
|
kgdb_initial_breakpoint();
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(kgdb_register_io_module);
|
|
|
|
/**
|
|
* kkgdb_unregister_io_module - unregister KGDB IO module
|
|
* @old_kgdb_io_ops: the io ops vector
|
|
*
|
|
* Unregister it with the KGDB core.
|
|
*/
|
|
void kgdb_unregister_io_module(struct kgdb_io *old_kgdb_io_ops)
|
|
{
|
|
BUG_ON(kgdb_connected);
|
|
|
|
/*
|
|
* KGDB is no longer able to communicate out, so
|
|
* unregister our callbacks and reset state.
|
|
*/
|
|
kgdb_unregister_callbacks();
|
|
|
|
spin_lock(&kgdb_registration_lock);
|
|
|
|
WARN_ON_ONCE(kgdb_io_ops != old_kgdb_io_ops);
|
|
kgdb_io_ops = NULL;
|
|
|
|
spin_unlock(&kgdb_registration_lock);
|
|
|
|
printk(KERN_INFO
|
|
"kgdb: Unregistered I/O driver %s, debugger disabled.\n",
|
|
old_kgdb_io_ops->name);
|
|
}
|
|
EXPORT_SYMBOL_GPL(kgdb_unregister_io_module);
|
|
|
|
/**
|
|
* kgdb_breakpoint - generate breakpoint exception
|
|
*
|
|
* This function will generate a breakpoint exception. It is used at the
|
|
* beginning of a program to sync up with a debugger and can be used
|
|
* otherwise as a quick means to stop program execution and "break" into
|
|
* the debugger.
|
|
*/
|
|
void kgdb_breakpoint(void)
|
|
{
|
|
atomic_set(&kgdb_setting_breakpoint, 1);
|
|
wmb(); /* Sync point before breakpoint */
|
|
arch_kgdb_breakpoint();
|
|
wmb(); /* Sync point after breakpoint */
|
|
atomic_set(&kgdb_setting_breakpoint, 0);
|
|
}
|
|
EXPORT_SYMBOL_GPL(kgdb_breakpoint);
|
|
|
|
static int __init opt_kgdb_wait(char *str)
|
|
{
|
|
kgdb_break_asap = 1;
|
|
|
|
if (kgdb_io_module_registered)
|
|
kgdb_initial_breakpoint();
|
|
|
|
return 0;
|
|
}
|
|
|
|
early_param("kgdbwait", opt_kgdb_wait);
|