HARDIRQ_BITS       40 include/linux/preempt.h #define NMI_SHIFT	(HARDIRQ_SHIFT + HARDIRQ_BITS)
HARDIRQ_BITS       46 include/linux/preempt.h #define HARDIRQ_MASK	(__IRQ_MASK(HARDIRQ_BITS) << HARDIRQ_SHIFT)