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/*
* Common SMP CPU bringup/teardown functions
*/
#include <linux/err.h>
#include <linux/smp.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/percpu.h>

#include "smpboot.h"

#ifdef CONFIG_GENERIC_SMP_IDLE_THREAD
/*
* For the hotplug case we keep the task structs around and reuse
* them.
*/
static DEFINE_PER_CPU(struct task_struct *, idle_threads);

struct task_struct * __cpuinit idle_thread_get(unsigned int cpu)
{
struct task_struct *tsk = per_cpu(idle_threads, cpu);

if (!tsk)
return ERR_PTR(-ENOMEM);
init_idle(tsk, cpu);
return tsk;
}

void __init idle_thread_set_boot_cpu(void)
{
per_cpu(idle_threads, smp_processor_id()) = current;
}

/**
* idle_init - Initialize the idle thread for a cpu
* @cpu: The cpu for which the idle thread should be initialized
*
* Creates the thread if it does not exist.
*/
static inline void idle_init(unsigned int cpu)
{
struct task_struct *tsk = per_cpu(idle_threads, cpu);

if (!tsk) {
tsk = fork_idle(cpu);
if (IS_ERR(tsk))
pr_err("SMP: fork_idle() failed for CPU %u\n", cpu);
else
per_cpu(idle_threads, cpu) = tsk;
}
}

/**
* idle_threads_init - Initialize idle threads for all cpus
*/
void __init idle_threads_init(void)
{
unsigned int cpu, boot_cpu;

boot_cpu = smp_processor_id();

for_each_possible_cpu(cpu) {
if (cpu != boot_cpu)
idle_init(cpu);
}
}
#endif
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