static void poll_channel(struct vmbus_channel *channel)
{
	if (channel->target_cpu != smp_processor_id())
		smp_call_function_single(channel->target_cpu,
					 hv_kvp_onchannelcallback,
					 channel, true);
	else
		hv_kvp_onchannelcallback(channel);
}

static int hw_breakpoint_reset_notify(struct notifier_block *self,
                                      unsigned long action,
                                      void *hcpu)
{
    int cpu = (long)hcpu;
    if (action == CPU_ONLINE)
        smp_call_function_single(cpu, reset_ctrl_regs, NULL, 1);
    return NOTIFY_OK;
}

/*
 * Powerstate information: The system enters/leaves a state, where
 * affected devices might stop.
 */
void tick_broadcast_on_off(unsigned long reason, int *oncpu)
{
	if (!cpu_isset(*oncpu, cpu_online_map))
		printk(KERN_ERR "tick-broadcast: ignoring broadcast for "
		       "offline CPU #%d\n", *oncpu);
	else
		smp_call_function_single(*oncpu, tick_do_broadcast_on_off,
					 &reason, 1);
}

static void bts_trace_start(struct trace_array *tr)
{
	int cpu;

	tracing_reset_online_cpus(tr);

	for_each_cpu(cpu, cpu_possible_mask)
		smp_call_function_single(cpu, bts_trace_start_cpu, NULL, 1);
}

static inline void do_cpuid(int cpu, u32 reg, u32 * data)
{
	struct cpuid_command cmd;

	cmd.reg = reg;
	cmd.data = data;

	smp_call_function_single(cpu, cpuid_smp_cpuid, &cmd, 1, 1);
}

static int __cpuinit kvm_cpu_notify(struct notifier_block *self,
				    unsigned long action, void *hcpu)
{
	int cpu = (unsigned long)hcpu;
	switch (action) {
	case CPU_ONLINE:
	case CPU_DOWN_FAILED:
	case CPU_ONLINE_FROZEN:
		smp_call_function_single(cpu, kvm_guest_cpu_online, NULL, 0);
		break;
	case CPU_DOWN_PREPARE:
	case CPU_DOWN_PREPARE_FROZEN:
		smp_call_function_single(cpu, kvm_guest_cpu_offline, NULL, 1);
		break;
	default:
		break;
	}
	return NOTIFY_OK;
}

/**
 * Save current fixed-range MTRR state of the BSP
 */
void mtrr_save_state(void)
{
	int cpu = get_cpu();

	if (cpu == 0)
		mtrr_save_fixed_ranges(NULL);
	else
		smp_call_function_single(0, mtrr_save_fixed_ranges, NULL, 1, 1);
	put_cpu();
}

static int
cpu_vsyscall_notifier(struct notifier_block *n, unsigned long action, void *arg)
{
	long cpu = (long)arg;

	if (action == CPU_ONLINE || action == CPU_ONLINE_FROZEN)
		smp_call_function_single(cpu, cpu_vsyscall_init, NULL, 1);

	return NOTIFY_DONE;
}

/* Select a source on the primary MUX. */
static void set_pri_clk_src(struct scalable *sc, u32 pri_src_sel)
{
	int cpu = sc - drv.scalable;
	if (sc != &drv.scalable[L2] && cpu_online(cpu)) {
		struct set_clk_src_args args = {
			.sc = sc,
			.src_sel = pri_src_sel,
		};
		smp_call_function_single(cpu, __set_cpu_pri_clk_src, &args, 1);
	} else {

/**
 * speedstep_target - set a new CPUFreq policy
 * @policy: new policy
 * @index: index of target frequency
 *
 * Sets a new CPUFreq policy.
 */
static int speedstep_target(struct cpufreq_policy *policy, unsigned int index)
{
	unsigned int policy_cpu;

	policy_cpu = cpumask_any_and(policy->cpus, cpu_online_mask);

	smp_call_function_single(policy_cpu, _speedstep_set_state, &index,
				 true);

	return 0;
}

static int __cpuinit cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
{
	long cpu = (long) hcpu;

	switch (action)
	{
	case CPU_ONLINE:
	case CPU_ONLINE_FROZEN:
		set_cpu_irq_affinity(cpu);
		smp_call_function_single(cpu, start_pmu, &pmu_paused, 1);
		break;

	case CPU_DEAD:
	case CPU_DEAD_FROZEN:
		smp_call_function_single(cpu, stop_pmu, NULL, 1);

		break;
	}
	return NOTIFY_OK;
}

static unsigned int speedstep_get(unsigned int cpu)
{
	unsigned int speed;

	/* You're supposed to ensure CPU is online. */
	if (smp_call_function_single(cpu, get_freq_data, &speed, 1) != 0)
		BUG();

	pr_debug("detected %u kHz as current frequency\n", speed);
	return speed;
}

static int twd_cpufreq_transition(struct notifier_block *nb,
	unsigned long state, void *data)
{
	struct cpufreq_freqs *freqs = data;

	if (state == CPUFREQ_POSTCHANGE || state == CPUFREQ_RESUMECHANGE)
		smp_call_function_single(freqs->cpu, twd_update_frequency,
			NULL, 1);

	return NOTIFY_OK;
}

static int jtag_mm_etm_probe(struct platform_device *pdev, uint32_t cpu)
{
	struct etm_ctx *etmdata;
	struct resource *res;
	struct device *dev = &pdev->dev;

	/* Allocate memory per cpu */
	etmdata = devm_kzalloc(dev, sizeof(struct etm_ctx), GFP_KERNEL);
	if (!etmdata)
		return -ENOMEM;

	etm[cpu] = etmdata;

	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "etm-base");
	if (!res)
		return -ENODEV;

	etmdata->base = devm_ioremap(dev, res->start, resource_size(res));
	if (!etmdata->base)
		return -EINVAL;

	/* Allocate etm state save space per core */
	etmdata->state = devm_kzalloc(dev,
				      MAX_ETM_STATE_SIZE * sizeof(uint64_t),
				      GFP_KERNEL);
	if (!etmdata->state)
		return -ENOMEM;

	spin_lock_init(&etmdata->spinlock);
	mutex_init(&etmdata->mutex);

	if (cnt++ == 0)
		register_hotcpu_notifier(&jtag_mm_etm_notifier);

	if (!smp_call_function_single(cpu, etm_init_arch_data, etmdata,
				      1))
		etmdata->init = true;

	if (etmdata->init) {
		mutex_lock(&etmdata->mutex);
		if (etm_arch_supported(etmdata->arch)) {
			if (scm_get_feat_version(TZ_DBG_ETM_FEAT_ID) <
			    TZ_DBG_ETM_VER)
				etmdata->save_restore_enabled = true;
			else
				pr_info("etm save-restore supported by TZ\n");
		} else
			pr_info("etm arch %u not supported\n", etmdata->arch);
		etmdata->enable = true;
		mutex_unlock(&etmdata->mutex);
	}
	return 0;
}

static ssize_t show_pw20_state(struct device *dev,
				struct device_attribute *attr, char *buf)
{
	u32 value;
	unsigned int cpu = dev->id;

	smp_call_function_single(cpu, do_show_pwrmgtcr0, &value, 1);

	value &= PWRMGTCR0_PW20_WAIT;

	return sprintf(buf, "%u\n", value ? 1 : 0);
}

int rdmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h)
{
	int err;
	struct msr_info rv;

	rv.msr_no = msr_no;
	err = smp_call_function_single(cpu, __rdmsr_safe_on_cpu, &rv, 1);
	*l = rv.l;
	*h = rv.h;

	return err ? err : rv.err;
}

int wrmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)
{
	int err;
	struct msr_info rv;

	rv.msr_no = msr_no;
	rv.l = l;
	rv.h = h;
	err = smp_call_function_single(cpu, __wrmsr_safe_on_cpu, &rv, 1);

	return err ? err : rv.err;
}

static int boot_secondary(unsigned int cpu, struct task_struct *ts)
{
	unsigned long timeout = jiffies + msecs_to_jiffies(1000);
	unsigned long ccount;
	int i;

#ifdef CONFIG_HOTPLUG_CPU
	WRITE_ONCE(cpu_start_id, cpu);
	/* Pairs with the third memw in the cpu_restart */
	mb();
	system_flush_invalidate_dcache_range((unsigned long)&cpu_start_id,
					     sizeof(cpu_start_id));
#endif
	smp_call_function_single(0, mx_cpu_start, (void *)cpu, 1);

	for (i = 0; i < 2; ++i) {
		do
			ccount = get_ccount();
		while (!ccount);

		WRITE_ONCE(cpu_start_ccount, ccount);

		do {
			/*
			 * Pairs with the first two memws in the
			 * .Lboot_secondary.
			 */
			mb();
			ccount = READ_ONCE(cpu_start_ccount);
		} while (ccount && time_before(jiffies, timeout));

		if (ccount) {
			smp_call_function_single(0, mx_cpu_stop,
						 (void *)cpu, 1);
			WRITE_ONCE(cpu_start_ccount, 0);
			return -EIO;
		}
	}
	return 0;
}

/*
 * return:
 * 		0: enable
 *		1: disable
 *		-1: error
 */
int 
kfm_cache_status_on_cpu(int cpu)
{
	int ret = 0;
	
	g_cache_status = 0;
	if((ret = smp_call_function_single(cpu, __kfm_caches_status, NULL, 1)))
		return ret;

	KFM_DBG(6, "get cpu %d cache status", cpu);

	return g_cache_status;
}

void cpuhp_report_idle_dead(void)
{
	struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state);

	BUG_ON(st->state != CPUHP_AP_OFFLINE);
	rcu_report_dead(smp_processor_id());
	st->state = CPUHP_AP_IDLE_DEAD;
	/*
	 * We cannot call complete after rcu_report_dead() so we delegate it
	 * to an online cpu.
	 */
	smp_call_function_single(cpumask_first(cpu_online_mask),
				 cpuhp_complete_idle_dead, st, 0);
}