#ifndef __x86_64_MMU_H#define __x86_64_MMU_H#include<linux/spinlock.h>#include<asm/semaphore.h>/* * The x86_64 doesn't have a mmu context, but * we put the segment information here. * * cpu_vm_mask is used to optimize ldt flushing. */typedefstruct{void*ldt;rwlock_tldtlock;intsize;structsemaphoresem;}mm_context_t;#endif