#ifndef _ASM_GENERIC_PERCPU_H_
  #define _ASM_GENERIC_PERCPU_H_

  #include <linux/compiler.h>

  #include <linux/threads.h>

  #include <linux/percpu-defs.h>

  #ifdef CONFIG_SMP

  /*
   * per_cpu_offset() is the offset that has to be added to a
   * percpu variable to get to the instance for a certain processor.
   *
   * Most arches use the __per_cpu_offset array for those offsets but
   * some arches have their own ways of determining the offset (x86_64, s390).
   */
  #ifndef __per_cpu_offset

  extern unsigned long __per_cpu_offset[NR_CPUS];

  #define per_cpu_offset(x) (__per_cpu_offset[x])

  #endif
  
  /*
   * Determine the offset for the currently active processor.
   * An arch may define __my_cpu_offset to provide a more effective
   * means of obtaining the offset to the per cpu variables of the
   * current processor.
   */
  #ifndef __my_cpu_offset
  #define __my_cpu_offset per_cpu_offset(raw_smp_processor_id())

  #endif
  #ifdef CONFIG_DEBUG_PREEMPT

  #define my_cpu_offset per_cpu_offset(smp_processor_id())
  #else
  #define my_cpu_offset __my_cpu_offset
  #endif
  
  /*
   * Add a offset to a pointer but keep the pointer as is.
   *
   * Only S390 provides its own means of moving the pointer.
   */
  #ifndef SHIFT_PERCPU_PTR
  #define SHIFT_PERCPU_PTR(__p, __offset)	RELOC_HIDE((__p), (__offset))
  #endif

  /*

   * A percpu variable may point to a discarded regions. The following are

   * established ways to produce a usable pointer from the percpu variable
   * offset.
   */
  #define per_cpu(var, cpu) \
  	(*SHIFT_PERCPU_PTR(&per_cpu_var(var), per_cpu_offset(cpu)))
  #define __get_cpu_var(var) \
  	(*SHIFT_PERCPU_PTR(&per_cpu_var(var), my_cpu_offset))
  #define __raw_get_cpu_var(var) \
  	(*SHIFT_PERCPU_PTR(&per_cpu_var(var), __my_cpu_offset))

  #ifdef CONFIG_HAVE_SETUP_PER_CPU_AREA

  extern void setup_per_cpu_areas(void);
  #endif

  #else /* ! SMP */

  #define per_cpu(var, cpu)			(*((void)(cpu), &per_cpu_var(var)))
  #define __get_cpu_var(var)			per_cpu_var(var)
  #define __raw_get_cpu_var(var)			per_cpu_var(var)

  
  #endif	/* SMP */

  #ifndef PER_CPU_BASE_SECTION
  #ifdef CONFIG_SMP
  #define PER_CPU_BASE_SECTION ".data.percpu"
  #else
  #define PER_CPU_BASE_SECTION ".data"
  #endif
  #endif
  
  #ifdef CONFIG_SMP
  
  #ifdef MODULE
  #define PER_CPU_SHARED_ALIGNED_SECTION ""
  #else
  #define PER_CPU_SHARED_ALIGNED_SECTION ".shared_aligned"
  #endif
  #define PER_CPU_FIRST_SECTION ".first"
  
  #else
  
  #define PER_CPU_SHARED_ALIGNED_SECTION ""
  #define PER_CPU_FIRST_SECTION ""
  
  #endif

  #ifndef PER_CPU_ATTRIBUTES
  #define PER_CPU_ATTRIBUTES
  #endif

  #endif /* _ASM_GENERIC_PERCPU_H_ */