LXR linux/include/linux/cpu.h

   1/*
   2 * include/linux/cpu.h - generic cpu definition
   3 *
   4 * This is mainly for topological representation. We define the 
   5 * basic 'struct cpu' here, which can be embedded in per-arch 
   6 * definitions of processors.
   7 *
   8 * Basic handling of the devices is done in drivers/base/cpu.c
   9 * and system devices are handled in drivers/base/sys.c. 
  10 *
  11 * CPUs are exported via driverfs in the class/cpu/devices/
  12 * directory. 
  13 *
  14 * Per-cpu interfaces can be implemented using a struct device_interface. 
  15 * See the following for how to do this: 
  16 * - drivers/base/intf.c 
  17 * - Documentation/driver-model/interface.txt
  18 */
  19#ifndef _LINUX_CPU_H_
  20#define _LINUX_CPU_H_
  21
  22#include <linux/sysdev.h>
  23#include <linux/node.h>
  24#include <linux/compiler.h>
  25#include <linux/cpumask.h>
  26#include <asm/semaphore.h>
  27
  28struct cpu {
  29        int node_id;            /* The node which contains the CPU */
  30        int no_control;         /* Should the sysfs control file be created? */
  31        struct sys_device sysdev;
  32};
  33
  34extern int register_cpu(struct cpu *, int, struct node *);
  35#ifdef CONFIG_HOTPLUG_CPU
  36extern void unregister_cpu(struct cpu *, struct node *);
  37#endif
  38struct notifier_block;
  39
  40#ifdef CONFIG_SMP
  41/* Need to know about CPUs going up/down? */
  42extern int register_cpu_notifier(struct notifier_block *nb);
  43extern void unregister_cpu_notifier(struct notifier_block *nb);
  44
  45int cpu_up(unsigned int cpu);
  46
  47#else
  48
  49static inline int register_cpu_notifier(struct notifier_block *nb)
  50{
  51        return 0;
  52}
  53static inline void unregister_cpu_notifier(struct notifier_block *nb)
  54{
  55}
  56
  57#endif /* CONFIG_SMP */
  58extern struct sysdev_class cpu_sysdev_class;
  59
  60#ifdef CONFIG_HOTPLUG_CPU
  61/* Stop CPUs going up and down. */
  62extern struct semaphore cpucontrol;
  63#define lock_cpu_hotplug()      down(&cpucontrol)
  64#define unlock_cpu_hotplug()    up(&cpucontrol)
  65#define lock_cpu_hotplug_interruptible() down_interruptible(&cpucontrol)
  66#define hotcpu_notifier(fn, pri) {                              \
  67        static struct notifier_block fn##_nb =                  \
  68                { .notifier_call = fn, .priority = pri };       \
  69        register_cpu_notifier(&fn##_nb);                        \
  70}
  71int cpu_down(unsigned int cpu);
  72#define cpu_is_offline(cpu) unlikely(!cpu_online(cpu))
  73#else
  74#define lock_cpu_hotplug()      do { } while (0)
  75#define unlock_cpu_hotplug()    do { } while (0)
  76#define lock_cpu_hotplug_interruptible() 0
  77#define hotcpu_notifier(fn, pri)
  78
  79/* CPUs don't go offline once they're online w/o CONFIG_HOTPLUG_CPU */
  80static inline int cpu_is_offline(int cpu) { return 0; }
  81#endif
  82
  83#endif /* _LINUX_CPU_H_ */
  84