#ifndef LINUX_HARDIRQ_H
  #define LINUX_HARDIRQ_H

  #include <linux/preempt.h>

  #include <linux/lockdep.h>

  #include <linux/ftrace_irq.h>

  #include <asm/hardirq.h>

  
  /*
   * 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 in theory reach the same as NR_IRQS.
   * In reality, the number of nested IRQS is limited to the stack
   * size as well. For archs with over 1000 IRQS it is not practical
   * to expect that they will all nest. We give a max of 10 bits for
   * hardirq nesting. An arch may choose to give less than 10 bits.
   * m68k expects it to be 8.

   *

   * - bits 16-25 are the hardirq count (max # of nested hardirqs: 1024)
   * - bit 26 is the NMI_MASK
   * - bit 28 is the PREEMPT_ACTIVE flag

   *
   * PREEMPT_MASK: 0x000000ff
   * SOFTIRQ_MASK: 0x0000ff00

   * HARDIRQ_MASK: 0x03ff0000
   *     NMI_MASK: 0x04000000

   */
  #define PREEMPT_BITS	8
  #define SOFTIRQ_BITS	8

  #define NMI_BITS	1

  #define MAX_HARDIRQ_BITS 10

  #ifndef HARDIRQ_BITS
  # define HARDIRQ_BITS	MAX_HARDIRQ_BITS

  #endif

  #if HARDIRQ_BITS > MAX_HARDIRQ_BITS
  #error HARDIRQ_BITS too high!

  #endif
  
  #define PREEMPT_SHIFT	0
  #define SOFTIRQ_SHIFT	(PREEMPT_SHIFT + PREEMPT_BITS)
  #define HARDIRQ_SHIFT	(SOFTIRQ_SHIFT + SOFTIRQ_BITS)

  #define NMI_SHIFT	(HARDIRQ_SHIFT + HARDIRQ_BITS)

  
  #define __IRQ_MASK(x)	((1UL << (x))-1)
  
  #define PREEMPT_MASK	(__IRQ_MASK(PREEMPT_BITS) << PREEMPT_SHIFT)

  #define SOFTIRQ_MASK	(__IRQ_MASK(SOFTIRQ_BITS) << SOFTIRQ_SHIFT)

  #define HARDIRQ_MASK	(__IRQ_MASK(HARDIRQ_BITS) << HARDIRQ_SHIFT)

  #define NMI_MASK	(__IRQ_MASK(NMI_BITS)     << NMI_SHIFT)

  
  #define PREEMPT_OFFSET	(1UL << PREEMPT_SHIFT)
  #define SOFTIRQ_OFFSET	(1UL << SOFTIRQ_SHIFT)
  #define HARDIRQ_OFFSET	(1UL << HARDIRQ_SHIFT)

  #define NMI_OFFSET	(1UL << NMI_SHIFT)

  #define SOFTIRQ_DISABLE_OFFSET	(2 * SOFTIRQ_OFFSET)

  #ifndef PREEMPT_ACTIVE
  #define PREEMPT_ACTIVE_BITS	1
  #define PREEMPT_ACTIVE_SHIFT	(NMI_SHIFT + NMI_BITS)
  #define PREEMPT_ACTIVE	(__IRQ_MASK(PREEMPT_ACTIVE_BITS) << PREEMPT_ACTIVE_SHIFT)
  #endif

  #if PREEMPT_ACTIVE < (1 << (NMI_SHIFT + NMI_BITS))

  #error PREEMPT_ACTIVE is too low!
  #endif

  #define hardirq_count()	(preempt_count() & HARDIRQ_MASK)
  #define softirq_count()	(preempt_count() & SOFTIRQ_MASK)

  #define irq_count()	(preempt_count() & (HARDIRQ_MASK | SOFTIRQ_MASK \
  				 | NMI_MASK))

  
  /*
   * Are we doing bottom half or hardware interrupt processing?
   * Are we in a softirq context? Interrupt context?

   * in_softirq - Are we currently processing softirq or have bh disabled?
   * in_serving_softirq - Are we currently processing softirq?

   */
  #define in_irq()		(hardirq_count())
  #define in_softirq()		(softirq_count())
  #define in_interrupt()		(irq_count())

  #define in_serving_softirq()	(softirq_count() & SOFTIRQ_OFFSET)

  /*
   * Are we in NMI context?
   */

  #define in_nmi()	(preempt_count() & NMI_MASK)

  #if defined(CONFIG_PREEMPT_COUNT)

  # define PREEMPT_CHECK_OFFSET 1
  #else

  # define PREEMPT_CHECK_OFFSET 0
  #endif

  /*
   * Are we running in atomic context?  WARNING: this macro cannot
   * always detect atomic context; in particular, it cannot know about
   * held spinlocks in non-preemptible kernels.  Thus it should not be
   * used in the general case to determine whether sleeping is possible.
   * Do not use in_atomic() in driver code.
   */

  #define in_atomic()	((preempt_count() & ~PREEMPT_ACTIVE) != 0)

  
  /*
   * Check whether we were atomic before we did preempt_disable():

   * (used by the scheduler, *after* releasing the kernel lock)

   */
  #define in_atomic_preempt_off() \
  		((preempt_count() & ~PREEMPT_ACTIVE) != PREEMPT_CHECK_OFFSET)

  #ifdef CONFIG_PREEMPT_COUNT

  # define preemptible()	(preempt_count() == 0 && !irqs_disabled())
  # define IRQ_EXIT_OFFSET (HARDIRQ_OFFSET-1)
  #else
  # define preemptible()	0
  # define IRQ_EXIT_OFFSET HARDIRQ_OFFSET
  #endif

  #if defined(CONFIG_SMP) || defined(CONFIG_GENERIC_HARDIRQS)

  extern void synchronize_irq(unsigned int irq);
  #else
  # define synchronize_irq(irq)	barrier()
  #endif

  struct task_struct;

  #if !defined(CONFIG_VIRT_CPU_ACCOUNTING) && !defined(CONFIG_IRQ_TIME_ACCOUNTING)

  static inline void account_system_vtime(struct task_struct *tsk)
  {
  }

  #else
  extern void account_system_vtime(struct task_struct *tsk);

  #endif

  #if defined(CONFIG_TINY_RCU) || defined(CONFIG_TINY_PREEMPT_RCU)

  
  static inline void rcu_nmi_enter(void)
  {
  }
  
  static inline void rcu_nmi_exit(void)
  {
  }
  
  #else

  extern void rcu_nmi_enter(void);
  extern void rcu_nmi_exit(void);

  #endif

  /*
   * It is safe to do non-atomic ops on ->hardirq_context,
   * because NMI handlers may not preempt and the ops are
   * always balanced, so the interrupted value of ->hardirq_context
   * will always be restored.
   */

  #define __irq_enter()					\
  	do {						\
  		account_system_vtime(current);		\
  		add_preempt_count(HARDIRQ_OFFSET);	\
  		trace_hardirq_enter();			\
  	} while (0)
  
  /*
   * Enter irq context (on NO_HZ, update jiffies):
   */

  extern void irq_enter(void);

  
  /*
   * Exit irq context without processing softirqs:
   */
  #define __irq_exit()					\
  	do {						\
  		trace_hardirq_exit();			\
  		account_system_vtime(current);		\
  		sub_preempt_count(HARDIRQ_OFFSET);	\

  	} while (0)

  /*
   * Exit irq context and process softirqs if needed:
   */

  extern void irq_exit(void);

  #define nmi_enter()						\
  	do {							\
  		ftrace_nmi_enter();				\
  		BUG_ON(in_nmi());				\
  		add_preempt_count(NMI_OFFSET + HARDIRQ_OFFSET);	\
  		lockdep_off();					\
  		rcu_nmi_enter();				\
  		trace_hardirq_enter();				\

  	} while (0)

  #define nmi_exit()						\
  	do {							\
  		trace_hardirq_exit();				\
  		rcu_nmi_exit();					\
  		lockdep_on();					\
  		BUG_ON(!in_nmi());				\
  		sub_preempt_count(NMI_OFFSET + HARDIRQ_OFFSET);	\
  		ftrace_nmi_exit();				\

  	} while (0)

  #endif /* LINUX_HARDIRQ_H */