extern spinlock_t i8253_lock;
static unsigned int get_time_pit(void){        extern spinlock_t i8253_lock;        unsigned long flags;        unsigned int count;        spin_lock_irqsave(&i8253_lock, flags);        outb_p(0x00, 0x43);        count = inb_p(0x40);        count |= inb_p(0x40) << 8;        spin_unlock_irqrestore(&i8253_lock, flags);        return count;}