#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>
  #include <linux/llist.h>
  
  extern void cpu_idle(void);
  
  typedef void (*smp_call_func_t)(void *info);
  struct call_single_data {
  	union {
  		struct list_head list;
  		struct llist_node llist;
  	};
  	smp_call_func_t func;
  	void *info;
  	u16 flags;
  };
  
  /* 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);
  
  /*
   * Call a function on all processors
   */
  int on_each_cpu(smp_call_func_t func, void *info, int wait);
  
  /*
   * Call a function on processors specified by mask, which might include
   * the local one.
   */
  void on_each_cpu_mask(const struct cpumask *mask, smp_call_func_t func,
  		void *info, bool wait);
  
  /*
   * Call a function on each processor for which the supplied function
   * cond_func returns a positive value. This may include the local
   * processor.
   */
  void on_each_cpu_cond(bool (*cond_func)(int cpu, void *info),
  		smp_call_func_t func, void *info, bool wait,
  		gfp_t gfp_flags);
  
  void __smp_call_function_single(int cpuid, struct call_single_data *data,
  				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, struct task_struct *tidle);
  
  /*
   * 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);
  
  int smp_call_function_any(const struct cpumask *mask,
  			  smp_call_func_t func, void *info, int wait);
  
  void kick_all_cpus_sync(void);
  
  /*
   * Generic and arch helpers
   */
  void __init call_function_init(void);
  void generic_smp_call_function_single_interrupt(void);
  #define generic_smp_call_function_interrupt \
  	generic_smp_call_function_single_interrupt
  
  /*
   * 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))
  
  static inline void smp_send_reschedule(int cpu) { }
  #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);
  }
  
  static inline void kick_all_cpus_sync(void) {  }
  
  #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);
  
  extern void arch_enable_nonboot_cpus_begin(void);
  extern void arch_enable_nonboot_cpus_end(void);
  
  void smp_setup_processor_id(void);
  
  #endif /* __LINUX_SMP_H */