#ifndef __LINUX_SMP_H
  #define __LINUX_SMP_H
  
  /*
   *	Generic SMP support
   *		Alan Cox. <alan@redhat.com>
   */

  #include <linux/errno.h>

  #include <linux/types.h>

  #include <linux/list.h>

  #include <linux/cpumask.h>

  #include <linux/init.h>

  
  extern void cpu_idle(void);

  typedef void (*smp_call_func_t)(void *info);

  struct call_single_data {
  	struct list_head list;

  	smp_call_func_t func;

  	void *info;

  	u16 flags;
  	u16 priv;

  };

  /* total number of cpus in this system (may exceed NR_CPUS) */
  extern unsigned int total_cpus;

  int smp_call_function_single(int cpuid, smp_call_func_t func, void *info,
  			     int wait);

  #ifdef CONFIG_SMP
  
  #include <linux/preempt.h>
  #include <linux/kernel.h>
  #include <linux/compiler.h>
  #include <linux/thread_info.h>
  #include <asm/smp.h>

  
  /*
   * main cross-CPU interfaces, handles INIT, TLB flush, STOP, etc.
   * (defined in asm header):

   */

  
  /*
   * stops all CPUs but the current one:
   */
  extern void smp_send_stop(void);
  
  /*
   * sends a 'reschedule' event to another CPU:
   */
  extern void smp_send_reschedule(int cpu);
  
  
  /*
   * Prepare machine for booting other CPUs.
   */
  extern void smp_prepare_cpus(unsigned int max_cpus);
  
  /*
   * Bring a CPU up
   */
  extern int __cpu_up(unsigned int cpunum);
  
  /*
   * Final polishing of CPUs
   */
  extern void smp_cpus_done(unsigned int max_cpus);
  
  /*
   * Call a function on all other processors
   */

  int smp_call_function(smp_call_func_t func, void *info, int wait);

  void smp_call_function_many(const struct cpumask *mask,

  			    smp_call_func_t func, void *info, bool wait);

  void __smp_call_function_single(int cpuid, struct call_single_data *data,
  				int wait);

  int smp_call_function_any(const struct cpumask *mask,

  			  smp_call_func_t func, void *info, int wait);

  /*
   * Generic and arch helpers
   */
  #ifdef CONFIG_USE_GENERIC_SMP_HELPERS

  void __init call_function_init(void);

  void generic_smp_call_function_single_interrupt(void);
  void generic_smp_call_function_interrupt(void);

  void ipi_call_lock(void);
  void ipi_call_unlock(void);
  void ipi_call_lock_irq(void);
  void ipi_call_unlock_irq(void);

  #else
  static inline void call_function_init(void) { }

  #endif

  /*
   * Call a function on all processors
   */

  int on_each_cpu(smp_call_func_t func, void *info, int wait);

  /*
   * Mark the boot cpu "online" so that it can call console drivers in
   * printk() and can access its per-cpu storage.
   */
  void smp_prepare_boot_cpu(void);

  extern unsigned int setup_max_cpus;

  extern void __init setup_nr_cpu_ids(void);
  extern void __init smp_init(void);

  #else /* !SMP */

  static inline void smp_send_stop(void) { }

  /*
   *	These macros fold the SMP functionality into a single CPU system
   */

  #define raw_smp_processor_id()			0

  static inline int up_smp_call_function(smp_call_func_t func, void *info)

  {
  	return 0;
  }

  #define smp_call_function(func, info, wait) \

  			(up_smp_call_function(func, info))

  #define on_each_cpu(func,info,wait)		\

  	({					\
  		local_irq_disable();		\
  		func(info);			\
  		local_irq_enable();		\
  		0;				\
  	})

  static inline void smp_send_reschedule(int cpu) { }

  #define num_booting_cpus()			1
  #define smp_prepare_boot_cpu()			do {} while (0)

  #define smp_call_function_many(mask, func, info, wait) \
  			(up_smp_call_function(func, info))

  static inline void call_function_init(void) { }

  
  static inline int

  smp_call_function_any(const struct cpumask *mask, smp_call_func_t func,

  		      void *info, int wait)

  {

  	return smp_call_function_single(0, func, info, wait);

  }

  #endif /* !SMP */
  
  /*

   * smp_processor_id(): get the current CPU ID.

   *

   * if DEBUG_PREEMPT is enabled then we check whether it is

   * used in a preemption-safe way. (smp_processor_id() is safe
   * if it's used in a preemption-off critical section, or in
   * a thread that is bound to the current CPU.)

   *

   * NOTE: raw_smp_processor_id() is for internal use only
   * (smp_processor_id() is the preferred variant), but in rare
   * instances it might also be used to turn off false positives
   * (i.e. smp_processor_id() use that the debugging code reports but
   * which use for some reason is legal). Don't use this to hack around
   * the warning message, as your code might not work under PREEMPT.

   */

  #ifdef CONFIG_DEBUG_PREEMPT
    extern unsigned int debug_smp_processor_id(void);
  # define smp_processor_id() debug_smp_processor_id()

  #else

  # define smp_processor_id() raw_smp_processor_id()

  #endif
  
  #define get_cpu()		({ preempt_disable(); smp_processor_id(); })
  #define put_cpu()		preempt_enable()

  /*
   * Callback to arch code if there's nosmp or maxcpus=0 on the
   * boot command line:
   */
  extern void arch_disable_smp_support(void);

  void smp_setup_processor_id(void);

  #endif /* __LINUX_SMP_H */