kernel/smpboot.h

#ifndef SMPBOOT_H
#define SMPBOOT_H

struct task_struct;

#ifdef CONFIG_GENERIC_SMP_IDLE_THREAD
struct task_struct *idle_thread_get(unsigned int cpu);
void idle_thread_set_boot_cpu(void);
void idle_threads_init(void);
#else
static inline struct task_struct *idle_thread_get(unsigned int cpu) { return NULL; }
static inline void idle_thread_set_boot_cpu(void) { }
static inline void idle_threads_init(void) { }
#endif

#endif