FreeBSD/Linux Kernel Cross Reference
sys/sys/smp.h

     /*-
      * ----------------------------------------------------------------------------
      * "THE BEER-WARE LICENSE" (Revision 42):
      * <phk@FreeBSD.org> wrote this file.  As long as you retain this notice you
      * can do whatever you want with this stuff. If we meet some day, and you think
      * this stuff is worth it, you can buy me a beer in return.   Poul-Henning Kamp
      * ----------------------------------------------------------------------------
      *
      * $FreeBSD$
     */
    
    #ifndef _SYS_SMP_H_
    #define _SYS_SMP_H_
    
    #ifdef _KERNEL
    
    #ifndef LOCORE
    
    #ifdef SMP
    
    /*
     * Topology of a NUMA or HTT system.
     *
     * The top level topology is an array of pointers to groups.  Each group
     * contains a bitmask of cpus in its group or subgroups.  It may also
     * contain a pointer to an array of child groups.
     *
     * The bitmasks at non leaf groups may be used by consumers who support
     * a smaller depth than the hardware provides.
     *
     * The topology may be omitted by systems where all CPUs are equal.
     */
    
    struct cpu_group {
            cpumask_t cg_mask;              /* Mask of cpus in this group. */
            int     cg_count;               /* Count of cpus in this group. */
            int     cg_children;            /* Number of children groups. */
            struct cpu_group *cg_child;     /* Optional child group. */
    };
    
    struct cpu_top {
            int     ct_count;               /* Count of groups. */
            struct cpu_group *ct_group;     /* Array of pointers to cpu groups. */
    };
    
    extern struct cpu_top *smp_topology;
    extern void (*cpustop_restartfunc)(void);
    extern int smp_active;
    extern int smp_cpus;
    extern volatile cpumask_t started_cpus;
    extern volatile cpumask_t stopped_cpus;
    extern cpumask_t idle_cpus_mask;
    extern cpumask_t hlt_cpus_mask;
    extern cpumask_t logical_cpus_mask;
    #endif /* SMP */
    
    extern u_int mp_maxid;
    extern int mp_maxcpus;
    extern int mp_ncpus;
    extern volatile int smp_started;
    
    extern cpumask_t all_cpus;
    
    /*
     * Macro allowing us to determine whether a CPU is absent at any given
     * time, thus permitting us to configure sparse maps of cpuid-dependent
     * (per-CPU) structures.
     */
    #define CPU_ABSENT(x_cpu)       ((all_cpus & (1 << (x_cpu))) == 0)
    
    /*
     * Macros to iterate over non-absent CPUs.  CPU_FOREACH() takes an
     * integer iterator and iterates over the available set of CPUs.
     * CPU_FIRST() returns the id of the first non-absent CPU.  CPU_NEXT()
     * returns the id of the next non-absent CPU.  It will wrap back to
     * CPU_FIRST() once the end of the list is reached.  The iterators are
     * currently implemented via inline functions.
     */
    #define CPU_FOREACH(i)                                                  \
            for ((i) = 0; (i) <= mp_maxid; (i)++)                           \
                    if (!CPU_ABSENT((i)))
    
    static __inline int
    cpu_first(void)
    {
            int i;
    
            for (i = 0;; i++)
                    if (!CPU_ABSENT(i))
                            return (i);
    }
    
    static __inline int
    cpu_next(int i)
    {
    
            for (;;) {
                    i++;
                    if (i > mp_maxid)
                           i = 0;
                   if (!CPU_ABSENT(i))
                           return (i);
           }
   }
   
   #define CPU_FIRST()     cpu_first()
   #define CPU_NEXT(i)     cpu_next((i))
   
   #ifdef SMP
   /*
    * Machine dependent functions used to initialize MP support.
    *
    * The cpu_mp_probe() should check to see if MP support is present and return
    * zero if it is not or non-zero if it is.  If MP support is present, then
    * cpu_mp_start() will be called so that MP can be enabled.  This function
    * should do things such as startup secondary processors.  It should also
    * setup mp_ncpus, all_cpus, and smp_cpus.  It should also ensure that
    * smp_active and smp_started are initialized at the appropriate time.
    * Once cpu_mp_start() returns, machine independent MP startup code will be
    * executed and a simple message will be output to the console.  Finally,
    * cpu_mp_announce() will be called so that machine dependent messages about
    * the MP support may be output to the console if desired.
    *
    * The cpu_setmaxid() function is called very early during the boot process
    * so that the MD code may set mp_maxid to provide an upper bound on CPU IDs
    * that other subsystems may use.  If a platform is not able to determine
    * the exact maximum ID that early, then it may set mp_maxid to MAXCPU - 1.
    */
   struct thread;
   
   void    cpu_mp_announce(void);
   int     cpu_mp_probe(void);
   void    cpu_mp_setmaxid(void);
   void    cpu_mp_start(void);
   
   void    forward_signal(struct thread *);
   void    forward_roundrobin(void);
   int     restart_cpus(cpumask_t);
   int     stop_cpus(cpumask_t);
   void    smp_rendezvous_action(void);
   extern  struct mtx smp_ipi_mtx;
   
   #endif /* SMP */
   void    smp_no_rendevous_barrier(void *);
   void    smp_rendezvous(void (*)(void *), 
                          void (*)(void *),
                          void (*)(void *),
                          void *arg);
   void    smp_rendezvous_cpus(cpumask_t,
                          void (*)(void *), 
                          void (*)(void *),
                          void (*)(void *),
                          void *arg);
   #endif /* !LOCORE */
   #endif /* _KERNEL */
   #endif /* _SYS_SMP_H_ */

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