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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_ */