mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-12-05 18:14:07 +08:00
38b8d208a4
We are going to move softlockup APIs out of <linux/sched.h>, which will have to be picked up from other headers and a couple of .c files. <linux/nmi.h> already includes <linux/sched.h>. Include the <linux/nmi.h> header in the files that are going to need it. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
1090 lines
25 KiB
C
1090 lines
25 KiB
C
/*
|
|
* Kernel Debug Core
|
|
*
|
|
* Maintainer: Jason Wessel <jason.wessel@windriver.com>
|
|
*
|
|
* Copyright (C) 2000-2001 VERITAS Software Corporation.
|
|
* Copyright (C) 2002-2004 Timesys Corporation
|
|
* Copyright (C) 2003-2004 Amit S. Kale <amitkale@linsyssoft.com>
|
|
* Copyright (C) 2004 Pavel Machek <pavel@ucw.cz>
|
|
* Copyright (C) 2004-2006 Tom Rini <trini@kernel.crashing.org>
|
|
* Copyright (C) 2004-2006 LinSysSoft Technologies Pvt. Ltd.
|
|
* Copyright (C) 2005-2009 Wind River Systems, Inc.
|
|
* Copyright (C) 2007 MontaVista Software, Inc.
|
|
* Copyright (C) 2008 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
|
|
*
|
|
* Contributors at various stages not listed above:
|
|
* Jason Wessel ( jason.wessel@windriver.com )
|
|
* George Anzinger <george@mvista.com>
|
|
* Anurekh Saxena (anurekh.saxena@timesys.com)
|
|
* Lake Stevens Instrument Division (Glenn Engel)
|
|
* Jim Kingdon, Cygnus Support.
|
|
*
|
|
* Original KGDB stub: David Grothe <dave@gcom.com>,
|
|
* Tigran Aivazian <tigran@sco.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.
|
|
*/
|
|
|
|
#define pr_fmt(fmt) "KGDB: " fmt
|
|
|
|
#include <linux/pid_namespace.h>
|
|
#include <linux/clocksource.h>
|
|
#include <linux/serial_core.h>
|
|
#include <linux/interrupt.h>
|
|
#include <linux/spinlock.h>
|
|
#include <linux/console.h>
|
|
#include <linux/threads.h>
|
|
#include <linux/uaccess.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/module.h>
|
|
#include <linux/ptrace.h>
|
|
#include <linux/string.h>
|
|
#include <linux/delay.h>
|
|
#include <linux/sched.h>
|
|
#include <linux/sysrq.h>
|
|
#include <linux/reboot.h>
|
|
#include <linux/init.h>
|
|
#include <linux/kgdb.h>
|
|
#include <linux/kdb.h>
|
|
#include <linux/nmi.h>
|
|
#include <linux/pid.h>
|
|
#include <linux/smp.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/vmacache.h>
|
|
#include <linux/rcupdate.h>
|
|
|
|
#include <asm/cacheflush.h>
|
|
#include <asm/byteorder.h>
|
|
#include <linux/atomic.h>
|
|
|
|
#include "debug_core.h"
|
|
|
|
static int kgdb_break_asap;
|
|
|
|
struct debuggerinfo_struct kgdb_info[NR_CPUS];
|
|
|
|
/**
|
|
* kgdb_connected - Is a host GDB connected to us?
|
|
*/
|
|
int kgdb_connected;
|
|
EXPORT_SYMBOL_GPL(kgdb_connected);
|
|
|
|
/* All the KGDB handlers are installed */
|
|
int kgdb_io_module_registered;
|
|
|
|
/* Guard for recursive entry */
|
|
static int exception_level;
|
|
|
|
struct kgdb_io *dbg_io_ops;
|
|
static DEFINE_SPINLOCK(kgdb_registration_lock);
|
|
|
|
/* Action for the reboot notifiter, a global allow kdb to change it */
|
|
static int kgdbreboot;
|
|
/* kgdb console driver is loaded */
|
|
static int kgdb_con_registered;
|
|
/* determine if kgdb console output should be used */
|
|
static int kgdb_use_con;
|
|
/* Flag for alternate operations for early debugging */
|
|
bool dbg_is_early = true;
|
|
/* Next cpu to become the master debug core */
|
|
int dbg_switch_cpu;
|
|
|
|
/* Use kdb or gdbserver mode */
|
|
int dbg_kdb_mode = 1;
|
|
|
|
static int __init opt_kgdb_con(char *str)
|
|
{
|
|
kgdb_use_con = 1;
|
|
return 0;
|
|
}
|
|
|
|
early_param("kgdbcon", opt_kgdb_con);
|
|
|
|
module_param(kgdb_use_con, int, 0644);
|
|
module_param(kgdbreboot, int, 0644);
|
|
|
|
/*
|
|
* Holds information about breakpoints in a kernel. These breakpoints are
|
|
* added and removed by gdb.
|
|
*/
|
|
static struct kgdb_bkpt kgdb_break[KGDB_MAX_BREAKPOINTS] = {
|
|
[0 ... KGDB_MAX_BREAKPOINTS-1] = { .state = BP_UNDEFINED }
|
|
};
|
|
|
|
/*
|
|
* The CPU# of the active CPU, or -1 if none:
|
|
*/
|
|
atomic_t kgdb_active = ATOMIC_INIT(-1);
|
|
EXPORT_SYMBOL_GPL(kgdb_active);
|
|
static DEFINE_RAW_SPINLOCK(dbg_master_lock);
|
|
static DEFINE_RAW_SPINLOCK(dbg_slave_lock);
|
|
|
|
/*
|
|
* We use NR_CPUs not PERCPU, in case kgdb is used to debug early
|
|
* bootup code (which might not have percpu set up yet):
|
|
*/
|
|
static atomic_t masters_in_kgdb;
|
|
static atomic_t slaves_in_kgdb;
|
|
static atomic_t kgdb_break_tasklet_var;
|
|
atomic_t kgdb_setting_breakpoint;
|
|
|
|
struct task_struct *kgdb_usethread;
|
|
struct task_struct *kgdb_contthread;
|
|
|
|
int kgdb_single_step;
|
|
static pid_t kgdb_sstep_pid;
|
|
|
|
/* to keep track of the CPU which is doing the single stepping*/
|
|
atomic_t kgdb_cpu_doing_single_step = ATOMIC_INIT(-1);
|
|
|
|
/*
|
|
* If you are debugging a problem where roundup (the collection of
|
|
* all other CPUs) is a problem [this should be extremely rare],
|
|
* then use the nokgdbroundup option to avoid roundup. In that case
|
|
* the other CPUs might interfere with your debugging context, so
|
|
* use this with care:
|
|
*/
|
|
static int kgdb_do_roundup = 1;
|
|
|
|
static int __init opt_nokgdbroundup(char *str)
|
|
{
|
|
kgdb_do_roundup = 0;
|
|
|
|
return 0;
|
|
}
|
|
|
|
early_param("nokgdbroundup", opt_nokgdbroundup);
|
|
|
|
/*
|
|
* Finally, some KGDB code :-)
|
|
*/
|
|
|
|
/*
|
|
* Weak aliases for breakpoint management,
|
|
* can be overriden by architectures when needed:
|
|
*/
|
|
int __weak kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt)
|
|
{
|
|
int err;
|
|
|
|
err = probe_kernel_read(bpt->saved_instr, (char *)bpt->bpt_addr,
|
|
BREAK_INSTR_SIZE);
|
|
if (err)
|
|
return err;
|
|
err = probe_kernel_write((char *)bpt->bpt_addr,
|
|
arch_kgdb_ops.gdb_bpt_instr, BREAK_INSTR_SIZE);
|
|
return err;
|
|
}
|
|
|
|
int __weak kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt)
|
|
{
|
|
return probe_kernel_write((char *)bpt->bpt_addr,
|
|
(char *)bpt->saved_instr, BREAK_INSTR_SIZE);
|
|
}
|
|
|
|
int __weak kgdb_validate_break_address(unsigned long addr)
|
|
{
|
|
struct kgdb_bkpt tmp;
|
|
int err;
|
|
/* Validate setting the breakpoint and then removing it. If the
|
|
* remove fails, the kernel needs to emit a bad message because we
|
|
* are deep trouble not being able to put things back the way we
|
|
* found them.
|
|
*/
|
|
tmp.bpt_addr = addr;
|
|
err = kgdb_arch_set_breakpoint(&tmp);
|
|
if (err)
|
|
return err;
|
|
err = kgdb_arch_remove_breakpoint(&tmp);
|
|
if (err)
|
|
pr_err("Critical breakpoint error, kernel memory destroyed at: %lx\n",
|
|
addr);
|
|
return err;
|
|
}
|
|
|
|
unsigned long __weak kgdb_arch_pc(int exception, struct pt_regs *regs)
|
|
{
|
|
return instruction_pointer(regs);
|
|
}
|
|
|
|
int __weak kgdb_arch_init(void)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
int __weak kgdb_skipexception(int exception, struct pt_regs *regs)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* 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) {
|
|
int i;
|
|
|
|
for (i = 0; i < VMACACHE_SIZE; i++) {
|
|
if (!current->vmacache.vmas[i])
|
|
continue;
|
|
flush_cache_range(current->vmacache.vmas[i],
|
|
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:
|
|
*/
|
|
int dbg_activate_sw_breakpoints(void)
|
|
{
|
|
int error;
|
|
int ret = 0;
|
|
int i;
|
|
|
|
for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
|
|
if (kgdb_break[i].state != BP_SET)
|
|
continue;
|
|
|
|
error = kgdb_arch_set_breakpoint(&kgdb_break[i]);
|
|
if (error) {
|
|
ret = error;
|
|
pr_info("BP install failed: %lx\n",
|
|
kgdb_break[i].bpt_addr);
|
|
continue;
|
|
}
|
|
|
|
kgdb_flush_swbreak_addr(kgdb_break[i].bpt_addr);
|
|
kgdb_break[i].state = BP_ACTIVE;
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
int dbg_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;
|
|
}
|
|
|
|
int dbg_deactivate_sw_breakpoints(void)
|
|
{
|
|
int error;
|
|
int ret = 0;
|
|
int i;
|
|
|
|
for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
|
|
if (kgdb_break[i].state != BP_ACTIVE)
|
|
continue;
|
|
error = kgdb_arch_remove_breakpoint(&kgdb_break[i]);
|
|
if (error) {
|
|
pr_info("BP remove failed: %lx\n",
|
|
kgdb_break[i].bpt_addr);
|
|
ret = error;
|
|
}
|
|
|
|
kgdb_flush_swbreak_addr(kgdb_break[i].bpt_addr);
|
|
kgdb_break[i].state = BP_SET;
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
int dbg_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 dbg_remove_all_break(void)
|
|
{
|
|
int error;
|
|
int i;
|
|
|
|
/* Clear memory breakpoints. */
|
|
for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
|
|
if (kgdb_break[i].state != BP_ACTIVE)
|
|
goto setundefined;
|
|
error = kgdb_arch_remove_breakpoint(&kgdb_break[i]);
|
|
if (error)
|
|
pr_err("breakpoint remove failed: %lx\n",
|
|
kgdb_break[i].bpt_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;
|
|
}
|
|
|
|
/*
|
|
* 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 (!dbg_io_ops)
|
|
return 0;
|
|
if (kgdb_connected)
|
|
return 1;
|
|
if (atomic_read(&kgdb_setting_breakpoint))
|
|
return 1;
|
|
if (print_wait) {
|
|
#ifdef CONFIG_KGDB_KDB
|
|
if (!dbg_kdb_mode)
|
|
pr_crit("waiting... or $3#33 for KDB\n");
|
|
#else
|
|
pr_crit("Waiting for remote debugger\n");
|
|
#endif
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
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);
|
|
dbg_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 (dbg_remove_sw_break(addr) == 0) {
|
|
exception_level = 0;
|
|
kgdb_skipexception(ks->ex_vector, ks->linux_regs);
|
|
dbg_activate_sw_breakpoints();
|
|
pr_crit("re-enter error: breakpoint removed %lx\n", addr);
|
|
WARN_ON_ONCE(1);
|
|
|
|
return 1;
|
|
}
|
|
dbg_remove_all_break();
|
|
kgdb_skipexception(ks->ex_vector, ks->linux_regs);
|
|
|
|
if (exception_level > 1) {
|
|
dump_stack();
|
|
panic("Recursive entry to debugger");
|
|
}
|
|
|
|
pr_crit("re-enter exception: ALL breakpoints killed\n");
|
|
#ifdef CONFIG_KGDB_KDB
|
|
/* Allow kdb to debug itself one level */
|
|
return 0;
|
|
#endif
|
|
dump_stack();
|
|
panic("Recursive entry to debugger");
|
|
|
|
return 1;
|
|
}
|
|
|
|
static void dbg_touch_watchdogs(void)
|
|
{
|
|
touch_softlockup_watchdog_sync();
|
|
clocksource_touch_watchdog();
|
|
rcu_cpu_stall_reset();
|
|
}
|
|
|
|
static int kgdb_cpu_enter(struct kgdb_state *ks, struct pt_regs *regs,
|
|
int exception_state)
|
|
{
|
|
unsigned long flags;
|
|
int sstep_tries = 100;
|
|
int error;
|
|
int cpu;
|
|
int trace_on = 0;
|
|
int online_cpus = num_online_cpus();
|
|
u64 time_left;
|
|
|
|
kgdb_info[ks->cpu].enter_kgdb++;
|
|
kgdb_info[ks->cpu].exception_state |= exception_state;
|
|
|
|
if (exception_state == DCPU_WANT_MASTER)
|
|
atomic_inc(&masters_in_kgdb);
|
|
else
|
|
atomic_inc(&slaves_in_kgdb);
|
|
|
|
if (arch_kgdb_ops.disable_hw_break)
|
|
arch_kgdb_ops.disable_hw_break(regs);
|
|
|
|
acquirelock:
|
|
/*
|
|
* Interrupts will be restored by the 'trap return' code, except when
|
|
* single stepping.
|
|
*/
|
|
local_irq_save(flags);
|
|
|
|
cpu = ks->cpu;
|
|
kgdb_info[cpu].debuggerinfo = regs;
|
|
kgdb_info[cpu].task = current;
|
|
kgdb_info[cpu].ret_state = 0;
|
|
kgdb_info[cpu].irq_depth = hardirq_count() >> HARDIRQ_SHIFT;
|
|
|
|
/* Make sure the above info reaches the primary CPU */
|
|
smp_mb();
|
|
|
|
if (exception_level == 1) {
|
|
if (raw_spin_trylock(&dbg_master_lock))
|
|
atomic_xchg(&kgdb_active, cpu);
|
|
goto cpu_master_loop;
|
|
}
|
|
|
|
/*
|
|
* CPU will loop if it is a slave or request to become a kgdb
|
|
* master cpu and acquire the kgdb_active lock:
|
|
*/
|
|
while (1) {
|
|
cpu_loop:
|
|
if (kgdb_info[cpu].exception_state & DCPU_NEXT_MASTER) {
|
|
kgdb_info[cpu].exception_state &= ~DCPU_NEXT_MASTER;
|
|
goto cpu_master_loop;
|
|
} else if (kgdb_info[cpu].exception_state & DCPU_WANT_MASTER) {
|
|
if (raw_spin_trylock(&dbg_master_lock)) {
|
|
atomic_xchg(&kgdb_active, cpu);
|
|
break;
|
|
}
|
|
} else if (kgdb_info[cpu].exception_state & DCPU_IS_SLAVE) {
|
|
if (!raw_spin_is_locked(&dbg_slave_lock))
|
|
goto return_normal;
|
|
} else {
|
|
return_normal:
|
|
/* Return to normal operation by executing any
|
|
* hw breakpoint fixup.
|
|
*/
|
|
if (arch_kgdb_ops.correct_hw_break)
|
|
arch_kgdb_ops.correct_hw_break();
|
|
if (trace_on)
|
|
tracing_on();
|
|
kgdb_info[cpu].exception_state &=
|
|
~(DCPU_WANT_MASTER | DCPU_IS_SLAVE);
|
|
kgdb_info[cpu].enter_kgdb--;
|
|
smp_mb__before_atomic();
|
|
atomic_dec(&slaves_in_kgdb);
|
|
dbg_touch_watchdogs();
|
|
local_irq_restore(flags);
|
|
return 0;
|
|
}
|
|
cpu_relax();
|
|
}
|
|
|
|
/*
|
|
* For single stepping, try to only enter on the processor
|
|
* that was single stepping. To guard against a deadlock, the
|
|
* kernel will only try for the value of sstep_tries before
|
|
* giving up and continuing on.
|
|
*/
|
|
if (atomic_read(&kgdb_cpu_doing_single_step) != -1 &&
|
|
(kgdb_info[cpu].task &&
|
|
kgdb_info[cpu].task->pid != kgdb_sstep_pid) && --sstep_tries) {
|
|
atomic_set(&kgdb_active, -1);
|
|
raw_spin_unlock(&dbg_master_lock);
|
|
dbg_touch_watchdogs();
|
|
local_irq_restore(flags);
|
|
|
|
goto acquirelock;
|
|
}
|
|
|
|
if (!kgdb_io_ready(1)) {
|
|
kgdb_info[cpu].ret_state = 1;
|
|
goto kgdb_restore; /* No I/O connection, 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 (dbg_io_ops->pre_exception)
|
|
dbg_io_ops->pre_exception();
|
|
|
|
/*
|
|
* 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)
|
|
raw_spin_lock(&dbg_slave_lock);
|
|
|
|
#ifdef CONFIG_SMP
|
|
/* If send_ready set, slaves are already waiting */
|
|
if (ks->send_ready)
|
|
atomic_set(ks->send_ready, 1);
|
|
|
|
/* Signal the other CPUs to enter kgdb_wait() */
|
|
else 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:
|
|
*/
|
|
time_left = MSEC_PER_SEC;
|
|
while (kgdb_do_roundup && --time_left &&
|
|
(atomic_read(&masters_in_kgdb) + atomic_read(&slaves_in_kgdb)) !=
|
|
online_cpus)
|
|
udelay(1000);
|
|
if (!time_left)
|
|
pr_crit("Timed out waiting for secondary CPUs.\n");
|
|
|
|
/*
|
|
* At this point the primary processor is completely
|
|
* in the debugger and all secondary CPUs are quiescent
|
|
*/
|
|
dbg_deactivate_sw_breakpoints();
|
|
kgdb_single_step = 0;
|
|
kgdb_contthread = current;
|
|
exception_level = 0;
|
|
trace_on = tracing_is_on();
|
|
if (trace_on)
|
|
tracing_off();
|
|
|
|
while (1) {
|
|
cpu_master_loop:
|
|
if (dbg_kdb_mode) {
|
|
kgdb_connected = 1;
|
|
error = kdb_stub(ks);
|
|
if (error == -1)
|
|
continue;
|
|
kgdb_connected = 0;
|
|
} else {
|
|
error = gdb_serial_stub(ks);
|
|
}
|
|
|
|
if (error == DBG_PASS_EVENT) {
|
|
dbg_kdb_mode = !dbg_kdb_mode;
|
|
} else if (error == DBG_SWITCH_CPU_EVENT) {
|
|
kgdb_info[dbg_switch_cpu].exception_state |=
|
|
DCPU_NEXT_MASTER;
|
|
goto cpu_loop;
|
|
} else {
|
|
kgdb_info[cpu].ret_state = error;
|
|
break;
|
|
}
|
|
}
|
|
|
|
/* Call the I/O driver's post_exception routine */
|
|
if (dbg_io_ops->post_exception)
|
|
dbg_io_ops->post_exception();
|
|
|
|
if (!kgdb_single_step) {
|
|
raw_spin_unlock(&dbg_slave_lock);
|
|
/* Wait till all the CPUs have quit from the debugger. */
|
|
while (kgdb_do_roundup && atomic_read(&slaves_in_kgdb))
|
|
cpu_relax();
|
|
}
|
|
|
|
kgdb_restore:
|
|
if (atomic_read(&kgdb_cpu_doing_single_step) != -1) {
|
|
int sstep_cpu = atomic_read(&kgdb_cpu_doing_single_step);
|
|
if (kgdb_info[sstep_cpu].task)
|
|
kgdb_sstep_pid = kgdb_info[sstep_cpu].task->pid;
|
|
else
|
|
kgdb_sstep_pid = 0;
|
|
}
|
|
if (arch_kgdb_ops.correct_hw_break)
|
|
arch_kgdb_ops.correct_hw_break();
|
|
if (trace_on)
|
|
tracing_on();
|
|
|
|
kgdb_info[cpu].exception_state &=
|
|
~(DCPU_WANT_MASTER | DCPU_IS_SLAVE);
|
|
kgdb_info[cpu].enter_kgdb--;
|
|
smp_mb__before_atomic();
|
|
atomic_dec(&masters_in_kgdb);
|
|
/* Free kgdb_active */
|
|
atomic_set(&kgdb_active, -1);
|
|
raw_spin_unlock(&dbg_master_lock);
|
|
dbg_touch_watchdogs();
|
|
local_irq_restore(flags);
|
|
|
|
return kgdb_info[cpu].ret_state;
|
|
}
|
|
|
|
/*
|
|
* 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;
|
|
int ret = 0;
|
|
|
|
if (arch_kgdb_ops.enable_nmi)
|
|
arch_kgdb_ops.enable_nmi(0);
|
|
/*
|
|
* Avoid entering the debugger if we were triggered due to an oops
|
|
* but panic_timeout indicates the system should automatically
|
|
* reboot on panic. We don't want to get stuck waiting for input
|
|
* on such systems, especially if its "just" an oops.
|
|
*/
|
|
if (signo != SIGTRAP && panic_timeout)
|
|
return 1;
|
|
|
|
memset(ks, 0, sizeof(struct kgdb_state));
|
|
ks->cpu = raw_smp_processor_id();
|
|
ks->ex_vector = evector;
|
|
ks->signo = signo;
|
|
ks->err_code = ecode;
|
|
ks->linux_regs = regs;
|
|
|
|
if (kgdb_reenter_check(ks))
|
|
goto out; /* Ouch, double exception ! */
|
|
if (kgdb_info[ks->cpu].enter_kgdb != 0)
|
|
goto out;
|
|
|
|
ret = kgdb_cpu_enter(ks, regs, DCPU_WANT_MASTER);
|
|
out:
|
|
if (arch_kgdb_ops.enable_nmi)
|
|
arch_kgdb_ops.enable_nmi(1);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* GDB places a breakpoint at this function to know dynamically
|
|
* loaded objects. It's not defined static so that only one instance with this
|
|
* name exists in the kernel.
|
|
*/
|
|
|
|
static int module_event(struct notifier_block *self, unsigned long val,
|
|
void *data)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
static struct notifier_block dbg_module_load_nb = {
|
|
.notifier_call = module_event,
|
|
};
|
|
|
|
int kgdb_nmicallback(int cpu, void *regs)
|
|
{
|
|
#ifdef CONFIG_SMP
|
|
struct kgdb_state kgdb_var;
|
|
struct kgdb_state *ks = &kgdb_var;
|
|
|
|
memset(ks, 0, sizeof(struct kgdb_state));
|
|
ks->cpu = cpu;
|
|
ks->linux_regs = regs;
|
|
|
|
if (kgdb_info[ks->cpu].enter_kgdb == 0 &&
|
|
raw_spin_is_locked(&dbg_master_lock)) {
|
|
kgdb_cpu_enter(ks, regs, DCPU_IS_SLAVE);
|
|
return 0;
|
|
}
|
|
#endif
|
|
return 1;
|
|
}
|
|
|
|
int kgdb_nmicallin(int cpu, int trapnr, void *regs, int err_code,
|
|
atomic_t *send_ready)
|
|
{
|
|
#ifdef CONFIG_SMP
|
|
if (!kgdb_io_ready(0) || !send_ready)
|
|
return 1;
|
|
|
|
if (kgdb_info[cpu].enter_kgdb == 0) {
|
|
struct kgdb_state kgdb_var;
|
|
struct kgdb_state *ks = &kgdb_var;
|
|
|
|
memset(ks, 0, sizeof(struct kgdb_state));
|
|
ks->cpu = cpu;
|
|
ks->ex_vector = trapnr;
|
|
ks->signo = SIGTRAP;
|
|
ks->err_code = err_code;
|
|
ks->linux_regs = regs;
|
|
ks->send_ready = send_ready;
|
|
kgdb_cpu_enter(ks, regs, DCPU_WANT_MASTER);
|
|
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 || dbg_kdb_mode)
|
|
return;
|
|
|
|
local_irq_save(flags);
|
|
gdbstub_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_dbg(int key)
|
|
{
|
|
if (!dbg_io_ops) {
|
|
pr_crit("ERROR: No KGDB I/O module available\n");
|
|
return;
|
|
}
|
|
if (!kgdb_connected) {
|
|
#ifdef CONFIG_KGDB_KDB
|
|
if (!dbg_kdb_mode)
|
|
pr_crit("KGDB or $3#33 for KDB\n");
|
|
#else
|
|
pr_crit("Entering KGDB\n");
|
|
#endif
|
|
}
|
|
|
|
kgdb_breakpoint();
|
|
}
|
|
|
|
static struct sysrq_key_op sysrq_dbg_op = {
|
|
.handler = sysrq_handle_dbg,
|
|
.help_msg = "debug(g)",
|
|
.action_msg = "DEBUG",
|
|
};
|
|
#endif
|
|
|
|
static int kgdb_panic_event(struct notifier_block *self,
|
|
unsigned long val,
|
|
void *data)
|
|
{
|
|
/*
|
|
* Avoid entering the debugger if we were triggered due to a panic
|
|
* We don't want to get stuck waiting for input from user in such case.
|
|
* panic_timeout indicates the system should automatically
|
|
* reboot on panic.
|
|
*/
|
|
if (panic_timeout)
|
|
return NOTIFY_DONE;
|
|
|
|
if (dbg_kdb_mode)
|
|
kdb_printf("PANIC: %s\n", (char *)data);
|
|
kgdb_breakpoint();
|
|
return NOTIFY_DONE;
|
|
}
|
|
|
|
static struct notifier_block kgdb_panic_event_nb = {
|
|
.notifier_call = kgdb_panic_event,
|
|
.priority = INT_MAX,
|
|
};
|
|
|
|
void __weak kgdb_arch_late(void)
|
|
{
|
|
}
|
|
|
|
void __init dbg_late_init(void)
|
|
{
|
|
dbg_is_early = false;
|
|
if (kgdb_io_module_registered)
|
|
kgdb_arch_late();
|
|
kdb_init(KDB_INIT_FULL);
|
|
}
|
|
|
|
static int
|
|
dbg_notify_reboot(struct notifier_block *this, unsigned long code, void *x)
|
|
{
|
|
/*
|
|
* Take the following action on reboot notify depending on value:
|
|
* 1 == Enter debugger
|
|
* 0 == [the default] detatch debug client
|
|
* -1 == Do nothing... and use this until the board resets
|
|
*/
|
|
switch (kgdbreboot) {
|
|
case 1:
|
|
kgdb_breakpoint();
|
|
case -1:
|
|
goto done;
|
|
}
|
|
if (!dbg_kdb_mode)
|
|
gdbstub_exit(code);
|
|
done:
|
|
return NOTIFY_DONE;
|
|
}
|
|
|
|
static struct notifier_block dbg_reboot_notifier = {
|
|
.notifier_call = dbg_notify_reboot,
|
|
.next = NULL,
|
|
.priority = INT_MAX,
|
|
};
|
|
|
|
static void kgdb_register_callbacks(void)
|
|
{
|
|
if (!kgdb_io_module_registered) {
|
|
kgdb_io_module_registered = 1;
|
|
kgdb_arch_init();
|
|
if (!dbg_is_early)
|
|
kgdb_arch_late();
|
|
register_module_notifier(&dbg_module_load_nb);
|
|
register_reboot_notifier(&dbg_reboot_notifier);
|
|
atomic_notifier_chain_register(&panic_notifier_list,
|
|
&kgdb_panic_event_nb);
|
|
#ifdef CONFIG_MAGIC_SYSRQ
|
|
register_sysrq_key('g', &sysrq_dbg_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;
|
|
unregister_reboot_notifier(&dbg_reboot_notifier);
|
|
unregister_module_notifier(&dbg_module_load_nb);
|
|
atomic_notifier_chain_unregister(&panic_notifier_list,
|
|
&kgdb_panic_event_nb);
|
|
kgdb_arch_exit();
|
|
#ifdef CONFIG_MAGIC_SYSRQ
|
|
unregister_sysrq_key('g', &sysrq_dbg_op);
|
|
#endif
|
|
if (kgdb_con_registered) {
|
|
unregister_console(&kgdbcons);
|
|
kgdb_con_registered = 0;
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* There are times a tasklet needs to be used vs a compiled in
|
|
* break point so as to cause an exception outside a kgdb I/O module,
|
|
* such as is the case with kgdboe, where calling a breakpoint in the
|
|
* I/O driver itself would be fatal.
|
|
*/
|
|
static void kgdb_tasklet_bpt(unsigned long ing)
|
|
{
|
|
kgdb_breakpoint();
|
|
atomic_set(&kgdb_break_tasklet_var, 0);
|
|
}
|
|
|
|
static DECLARE_TASKLET(kgdb_tasklet_breakpoint, kgdb_tasklet_bpt, 0);
|
|
|
|
void kgdb_schedule_breakpoint(void)
|
|
{
|
|
if (atomic_read(&kgdb_break_tasklet_var) ||
|
|
atomic_read(&kgdb_active) != -1 ||
|
|
atomic_read(&kgdb_setting_breakpoint))
|
|
return;
|
|
atomic_inc(&kgdb_break_tasklet_var);
|
|
tasklet_schedule(&kgdb_tasklet_breakpoint);
|
|
}
|
|
EXPORT_SYMBOL_GPL(kgdb_schedule_breakpoint);
|
|
|
|
static void kgdb_initial_breakpoint(void)
|
|
{
|
|
kgdb_break_asap = 0;
|
|
|
|
pr_crit("Waiting for connection from remote gdb...\n");
|
|
kgdb_breakpoint();
|
|
}
|
|
|
|
/**
|
|
* kgdb_register_io_module - register KGDB IO module
|
|
* @new_dbg_io_ops: the io ops vector
|
|
*
|
|
* Register it with the KGDB core.
|
|
*/
|
|
int kgdb_register_io_module(struct kgdb_io *new_dbg_io_ops)
|
|
{
|
|
int err;
|
|
|
|
spin_lock(&kgdb_registration_lock);
|
|
|
|
if (dbg_io_ops) {
|
|
spin_unlock(&kgdb_registration_lock);
|
|
|
|
pr_err("Another I/O driver is already registered with KGDB\n");
|
|
return -EBUSY;
|
|
}
|
|
|
|
if (new_dbg_io_ops->init) {
|
|
err = new_dbg_io_ops->init();
|
|
if (err) {
|
|
spin_unlock(&kgdb_registration_lock);
|
|
return err;
|
|
}
|
|
}
|
|
|
|
dbg_io_ops = new_dbg_io_ops;
|
|
|
|
spin_unlock(&kgdb_registration_lock);
|
|
|
|
pr_info("Registered I/O driver %s\n", new_dbg_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_dbg_io_ops: the io ops vector
|
|
*
|
|
* Unregister it with the KGDB core.
|
|
*/
|
|
void kgdb_unregister_io_module(struct kgdb_io *old_dbg_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(dbg_io_ops != old_dbg_io_ops);
|
|
dbg_io_ops = NULL;
|
|
|
|
spin_unlock(&kgdb_registration_lock);
|
|
|
|
pr_info("Unregistered I/O driver %s, debugger disabled\n",
|
|
old_dbg_io_ops->name);
|
|
}
|
|
EXPORT_SYMBOL_GPL(kgdb_unregister_io_module);
|
|
|
|
int dbg_io_get_char(void)
|
|
{
|
|
int ret = dbg_io_ops->read_char();
|
|
if (ret == NO_POLL_CHAR)
|
|
return -1;
|
|
if (!dbg_kdb_mode)
|
|
return ret;
|
|
if (ret == 127)
|
|
return 8;
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* 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.
|
|
*/
|
|
noinline void kgdb_breakpoint(void)
|
|
{
|
|
atomic_inc(&kgdb_setting_breakpoint);
|
|
wmb(); /* Sync point before breakpoint */
|
|
arch_kgdb_breakpoint();
|
|
wmb(); /* Sync point after breakpoint */
|
|
atomic_dec(&kgdb_setting_breakpoint);
|
|
}
|
|
EXPORT_SYMBOL_GPL(kgdb_breakpoint);
|
|
|
|
static int __init opt_kgdb_wait(char *str)
|
|
{
|
|
kgdb_break_asap = 1;
|
|
|
|
kdb_init(KDB_INIT_EARLY);
|
|
if (kgdb_io_module_registered)
|
|
kgdb_initial_breakpoint();
|
|
|
|
return 0;
|
|
}
|
|
|
|
early_param("kgdbwait", opt_kgdb_wait);
|