+/*
+ * We put the hardirq and softirq counter into the preemption
+ * counter. The bitmask has the following meaning:
+ *
+ * - bits 0-7 are the preemption count (max preemption depth: 256)
+ * - bits 8-15 are the softirq count (max # of softirqs: 256)
+ *
+ * The hardirq count can be overridden per architecture, the default is:
+ *
+ * - bits 16-27 are the hardirq count (max # of hardirqs: 4096)
+ * - ( bit 28 is the PREEMPT_ACTIVE flag. )
+ *
+ * PREEMPT_MASK: 0x000000ff
+ * SOFTIRQ_MASK: 0x0000ff00
+ * HARDIRQ_MASK: 0x0fff0000
+ */
+#define PREEMPT_BITS 8
+#define SOFTIRQ_BITS 8
+
+#ifndef HARDIRQ_BITS
+#define HARDIRQ_BITS 12
+/*
+ * The hardirq mask has to be large enough to have space for potentially
+ * all IRQ sources in the system nesting on a single CPU.
+ */
+#if (1 << HARDIRQ_BITS) < NR_IRQS
+# error HARDIRQ_BITS is too low!
+#endif
+#endif
+
+#define PREEMPT_SHIFT 0
+#define SOFTIRQ_SHIFT (PREEMPT_SHIFT + PREEMPT_BITS)
+#define HARDIRQ_SHIFT (SOFTIRQ_SHIFT + SOFTIRQ_BITS)
+