1. 根目录:
2. include
3. linux
4. start_kernel.h

#ifndef _LINUX_START_KERNEL_H
#define _LINUX_START_KERNEL_H

#include <linux/linkage.h>
#include <linux/init.h>

/* Define the prototype for start_kernel here, rather than cluttering
   up something else. */

extern asmlinkage void __init start_kernel(void);

#endif /* _LINUX_START_KERNEL_H */