打印内核函数的地址 system_map

void get_system_map_addr( unsigned long long int in_var )      
{                                                 
    extern unsigned char secondary_startup_64[];  
    //ffffffff81000030 T secondary_startup_64
    unsigned long long int g_offset, result;
    printk(KERN_NOTICE "secondary_startup_64 = 0x%llx\n", secondary_startup_64 );   
    g_offset = secondary_startup_64;
    printk(KERN_NOTICE "g_offset = 0x%llx\n", g_offset );   
    g_offset = g_offset - 0xffffffff81000030;
    printk(KERN_NOTICE "g_offset = 0x%llx\n", g_offset );   
    printk(KERN_NOTICE "in_var = 0x%llx\n", in_var );
    result = in_var - g_offset;
    printk(KERN_NOTICE "result = %llx\n", result );
}