BUG_ON(irq > 256);
asmlinkage unsigned int do_IRQ(struct pt_regs *regs){		/* high bits used in ret_from_ code  */	unsigned irq = regs->orig_rax & 0xff;	irq_enter();	BUG_ON(irq > 256);	__do_IRQ(irq, regs);	irq_exit();	return 1;}