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Commit 9b377e21 authored by Sebastian Andrzej Siewior's avatar Sebastian Andrzej Siewior Committed by Thomas Gleixner
Browse files

ARM/hw_breakpoint: Convert to hotplug state machine 



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: default avatarSebastian 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: default avatarThomas Gleixner <tglx@linutronix.de>
parent a3c9b14f

arch/arm/kernel/hw_breakpoint.c

+22 −25
Original line number Diff line number Diff line
@@ -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;

}