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ARM/hw_breakpoint: Convert to hotplug state machine

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Install the callbacks via the state machine and let the core invoke
the callbacks on the already online CPUs.

smp_call_function_single() has been removed because the function is already
invoked on the target CPU.

[ tglx: Added protection agaist hotplug back according to discussion with Will ]

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: rt@linuxtronix.de
Cc: Will Deacon <will.deacon@arm.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/20161117183541.8588-16-bigeasy@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Sebastian Andrzej Siewior 2016-11-17 19:35:36 +01:00 committed by Thomas Gleixner
parent a3c9b14f6f
commit 9b377e217f
1 changed files with 22 additions and 25 deletions
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47
arch/arm/kernel/hw_breakpoint.c
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@ -925,9 +925,9 @@ static bool core_has_os_save_restore(void)
}
}
static void reset_ctrl_regs(void *unused)
static void reset_ctrl_regs(unsigned int cpu)
{
int i, raw_num_brps, err = 0, cpu = smp_processor_id();
int i, raw_num_brps, err = 0;
u32 val;
/*
@ -1020,25 +1020,20 @@ static void reset_ctrl_regs(void *unused)
cpumask_or(&debug_err_mask, &debug_err_mask, cpumask_of(cpu));
}
static int dbg_reset_notify(struct notifier_block *self,
unsigned long action, void *cpu)
static int dbg_reset_online(unsigned int cpu)
{
if ((action & ~CPU_TASKS_FROZEN) == CPU_ONLINE)
smp_call_function_single((int)cpu, reset_ctrl_regs, NULL, 1);
return NOTIFY_OK;
local_irq_disable();
reset_ctrl_regs(cpu);
local_irq_enable();
return 0;
}
static struct notifier_block dbg_reset_nb = {
.notifier_call = dbg_reset_notify,
};
#ifdef CONFIG_CPU_PM
static int dbg_cpu_pm_notify(struct notifier_block *self, unsigned long action,
void *v)
{
if (action == CPU_PM_EXIT)
reset_ctrl_regs(NULL);
reset_ctrl_regs(smp_processor_id());
return NOTIFY_OK;
}
@ -1059,6 +1054,8 @@ static inline void pm_init(void)
static int __init arch_hw_breakpoint_init(void)
{
int ret;
debug_arch = get_debug_arch();
if (!debug_arch_supported()) {
@ -1072,25 +1069,28 @@ static int __init arch_hw_breakpoint_init(void)
core_num_brps = get_num_brps();
core_num_wrps = get_num_wrps();
cpu_notifier_register_begin();
/*
* We need to tread carefully here because DBGSWENABLE may be
* driven low on this core and there isn't an architected way to
* determine that.
*/
get_online_cpus();
register_undef_hook(&debug_reg_hook);
/*
* Reset the breakpoint resources. We assume that a halting
* debugger will leave the world in a nice state for us.
* Register CPU notifier which resets the breakpoint resources. We
* assume that a halting debugger will leave the world in a nice state
* for us.
*/
on_each_cpu(reset_ctrl_regs, NULL, 1);
ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "arm/hw_breakpoint:online",
dbg_reset_online, NULL);
unregister_undef_hook(&debug_reg_hook);
if (!cpumask_empty(&debug_err_mask)) {
if (WARN_ON(ret < 0) || !cpumask_empty(&debug_err_mask)) {
core_num_brps = 0;
core_num_wrps = 0;
cpu_notifier_register_done();
if (ret > 0)
cpuhp_remove_state_nocalls(ret);
put_online_cpus();
return 0;
}
@ -1108,12 +1108,9 @@ static int __init arch_hw_breakpoint_init(void)
TRAP_HWBKPT, "watchpoint debug exception");
hook_ifault_code(FAULT_CODE_DEBUG, hw_breakpoint_pending, SIGTRAP,
TRAP_HWBKPT, "breakpoint debug exception");
put_online_cpus();
/* Register hotplug and PM notifiers. */
__register_cpu_notifier(&dbg_reset_nb);
cpu_notifier_register_done();
/* Register PM notifiers. */
pm_init();
return 0;
}