HARDIRQ_BITS       33 include/linux/preempt_mask.h #define NMI_SHIFT	(HARDIRQ_SHIFT + HARDIRQ_BITS)
HARDIRQ_BITS       39 include/linux/preempt_mask.h #define HARDIRQ_MASK	(__IRQ_MASK(HARDIRQ_BITS) << HARDIRQ_SHIFT)