static inline struct task_struct * get_current(void)
{
        struct task_struct *current;
        __asm__("andl %%esp,%0; ":"=r" (current) : "" (~8191UL));
        // 8191 = 0x001FFF, ~8191 = 0xFFFFE000 이다. 변환해보면
        // __asm__("andl %%esp,%0; ":current=EAX : EAX = 0xFFFFE000);
         return current;
  }