void pvclock_touch_watchdogs(void)
{
touch_softlockup_watchdog_sync();
clocksource_touch_watchdog();
rcu_cpu_stall_reset();
reset_hung_task_detector();
}
static int kgdb_cpu_enter(struct kgdb_state *ks, struct pt_regs *regs)
{
unsigned long flags;
int sstep_tries = 100;
int error;
int i, cpu;
int trace_on = 0;
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 before
* our cpu_in_kgdb[] flag setting does:
*/
atomic_inc(&cpu_in_kgdb[cpu]);
if (exception_level == 1)
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 (atomic_cmpxchg(&kgdb_active, -1, cpu) == cpu)
break;
} else if (kgdb_info[cpu].exception_state & DCPU_IS_SLAVE) {
if (!atomic_read(&passive_cpu_wait[cpu]))
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();
atomic_dec(&cpu_in_kgdb[cpu]);
touch_softlockup_watchdog_sync();
clocksource_touch_watchdog();
local_irq_restore(flags);
return 0;
}
cpu_relax();
}
/*
* For single stepping, try to only enter on the processor
* that was single stepping. To gaurd 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);
touch_softlockup_watchdog_sync();
clocksource_touch_watchdog();
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();
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_inc(&passive_cpu_wait[i]);
}
#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 (kgdb_do_roundup && !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
*/
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);
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) {
dbg_cpu_switch(cpu, dbg_switch_cpu);
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();
atomic_dec(&cpu_in_kgdb[ks->cpu]);
if (!kgdb_single_step) {
for (i = NR_CPUS-1; i >= 0; i--)
atomic_dec(&passive_cpu_wait[i]);
/*
* Wait till all the CPUs have quit from the debugger,
* but allow a CPU that hit an exception and is
* waiting to become the master to remain in the debug
* core.
*/
for_each_online_cpu(i) {
while (kgdb_do_roundup &&
atomic_read(&cpu_in_kgdb[i]) &&
!(kgdb_info[i].exception_state &
DCPU_WANT_MASTER))
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 (trace_on)
tracing_on();
/* Free kgdb_active */
atomic_set(&kgdb_active, -1);
touch_softlockup_watchdog_sync();
clocksource_touch_watchdog();
local_irq_restore(flags);
return kgdb_info[cpu].ret_state;
}
static void dbg_touch_watchdogs(void)
{
touch_softlockup_watchdog_sync();
clocksource_touch_watchdog();
rcu_cpu_stall_reset();
}