int disable_nonboot_cpus(void)
{
	int cpu, first_cpu, error = 0;

	cpu_maps_update_begin();
	first_cpu = cpumask_first(cpu_online_mask);
	/*
	 * We take down all of the non-boot CPUs in one shot to avoid races
	 * with the userspace trying to use the CPU hotplug at the same time
	 */
	cpumask_clear(frozen_cpus);

	printk("Disabling non-boot CPUs ...\n");
	for_each_online_cpu(cpu) {
		if (cpu == first_cpu)
			continue;
		error = _cpu_down(cpu, 1);
		if (!error)
			cpumask_set_cpu(cpu, frozen_cpus);
		else {
			printk(KERN_ERR "Error taking CPU%d down: %d\n",
				cpu, error);
			break;
		}
	}

	if (!error) {
		BUG_ON(num_online_cpus() > 1);
		/* Make sure the CPUs won't be enabled by someone else */
		cpu_hotplug_disabled = 1;
	} else {
		printk(KERN_ERR "Non-boot CPUs are not disabled\n");
	}
	cpu_maps_update_done();
	return error;
}

void __ref enable_nonboot_cpus(void)
{
	int cpu, error;

	/* Allow everyone to use the CPU hotplug again */
	cpu_maps_update_begin();
	cpu_hotplug_disabled = 0;
	if (cpumask_empty(frozen_cpus))
		goto out;

	pr_info("Enabling non-boot CPUs ...\n");

	arch_enable_nonboot_cpus_begin();

	for_each_cpu(cpu, frozen_cpus) {
		trace_suspend_resume(TPS("CPU_ON"), cpu, true);
		error = _cpu_up(cpu, 1);
		trace_suspend_resume(TPS("CPU_ON"), cpu, false);
		if (!error) {
			pr_info("CPU%d is up\n", cpu);
			continue;
		}
		pr_warn("Error taking CPU%d up: %d\n", cpu, error);
	}

void cpu_hotplug_enable(void)
{
	cpu_maps_update_begin();
	WARN_ON(--cpu_hotplug_disabled < 0);
	cpu_maps_update_done();
}

/*
 * Wait for currently running CPU hotplug operations to complete (if any) and
 * disable future CPU hotplug (from sysfs). The 'cpu_add_remove_lock' protects
 * the 'cpu_hotplug_disabled' flag. The same lock is also acquired by the
 * hotplug path before performing hotplug operations. So acquiring that lock
 * guarantees mutual exclusion from any currently running hotplug operations.
 */
void cpu_hotplug_disable(void)
{
	cpu_maps_update_begin();
	cpu_hotplug_disabled++;
	cpu_maps_update_done();
}

int __cpuinit cpu_up(unsigned int cpu)
{
	int err = 0;

#ifdef	CONFIG_MEMORY_HOTPLUG
	int nid;
	pg_data_t	*pgdat;
#endif

	if (!cpu_possible(cpu)) {
		printk(KERN_ERR "can't online cpu %d because it is not "
			"configured as may-hotadd at boot time\n", cpu);
#if defined(CONFIG_IA64)
		printk(KERN_ERR "please check additional_cpus= boot "
				"parameter\n");
#endif
		return -EINVAL;
	}

#ifdef	CONFIG_MEMORY_HOTPLUG
	nid = cpu_to_node(cpu);
	if (!node_online(nid)) {
		err = mem_online_node(nid);
		if (err)
			return err;
	}

	pgdat = NODE_DATA(nid);
	if (!pgdat) {
		printk(KERN_ERR
			"Can't online cpu %d due to NULL pgdat\n", cpu);
		return -ENOMEM;
	}

	if (pgdat->node_zonelists->_zonerefs->zone == NULL) {
		mutex_lock(&zonelists_mutex);
		build_all_zonelists(NULL);
		mutex_unlock(&zonelists_mutex);
	}
#endif

	cpu_maps_update_begin();

#ifdef CONFIG_CPU_FREQ_GOV_K3HOTPLUG
	if ((gcpu_num_limit.block != 0)
		&& (num_online_cpus() >= gcpu_num_limit.block)) {
		pr_err("[%s]cpu lock is %d can not hotplug cpu.\n",
			__func__, gcpu_num_limit.block);
		err = -EPERM;
		goto out;
	} else if ((gcpu_num_limit.block == 0)
				&& (num_online_cpus() >= gcpu_num_limit.max)) {
		pr_err("[%s]cpu max is %d can not hotplug cpu.\n",
			__func__, gcpu_num_limit.max);
		err = -EPERM;
		goto out;
	}

	if (cpu != (num_online_cpus())) {
		err = -EPERM;
		goto out;
	}
#endif

	if (cpu_hotplug_disabled) {
		err = -EBUSY;
		goto out;
	}

	err = _cpu_up(cpu, 0);

out:
	cpu_maps_update_done();
	return err;
}

int disable_nonboot_cpus(void)
{
	int cpu, first_cpu, error = 0;
#ifdef CONFIG_ARM_EXYNOS_MP_CPUFREQ
	int lated_cpu;
#endif

#ifdef CONFIG_ARM_EXYNOS_MP_CPUFREQ
	if (exynos_boot_cluster == CA7)
		lated_cpu = NR_CA7;
	else
		lated_cpu = NR_CA15;
#endif

	cpu_maps_update_begin();
	first_cpu = cpumask_first(cpu_online_mask);
	/*
	 * We take down all of the non-boot CPUs in one shot to avoid races
	 * with the userspace trying to use the CPU hotplug at the same time
	 */
	cpumask_clear(frozen_cpus);
	arch_disable_nonboot_cpus_begin();

	printk("Disabling non-boot CPUs ...\n");
	for_each_online_cpu(cpu) {
#if defined(CONFIG_ARM_EXYNOS_MP_CPUFREQ)
		if (cpu == first_cpu || cpu == lated_cpu)
#else
		if (cpu == first_cpu)
#endif
			continue;
		error = _cpu_down(cpu, 1);
		if (!error)
			cpumask_set_cpu(cpu, frozen_cpus);
		else {
			printk(KERN_ERR "Error taking CPU%d down: %d\n",
				cpu, error);
			break;
		}
	}

#ifdef CONFIG_ARM_EXYNOS_MP_CPUFREQ
	if (num_online_cpus() > 1) {
		error = _cpu_down(lated_cpu, 1);
		if (!error)
			cpumask_set_cpu(lated_cpu, frozen_cpus);
		else
			printk(KERN_ERR "Error taking CPU%d down: %d\n",
				lated_cpu, error);
	}
#endif

	arch_disable_nonboot_cpus_end();

	if (!error) {
		BUG_ON(num_online_cpus() > 1);
		/* Make sure the CPUs won't be enabled by someone else */
		cpu_hotplug_disabled = 1;
	} else {
		printk(KERN_ERR "Non-boot CPUs are not disabled\n");
	}
	cpu_maps_update_done();
	return error;
}