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 sysfs 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 *cpu, int num);
35extern struct sys_device *get_cpu_sysdev(unsigned cpu);
36#ifdef CONFIG_HOTPLUG_CPU
37extern void unregister_cpu(struct cpu *cpu);
38#endif
39struct notifier_block;
40
41#ifdef CONFIG_SMP
42/* Need to know about CPUs going up/down? */
43extern int register_cpu_notifier(struct notifier_block *nb);
44#ifdef CONFIG_HOTPLUG_CPU
45extern void unregister_cpu_notifier(struct notifier_block *nb);
46#else
47static inline void unregister_cpu_notifier(struct notifier_block *nb)
48{
49}
50#endif
51
52int cpu_up(unsigned int cpu);
53
54#else
55
56static inline int register_cpu_notifier(struct notifier_block *nb)
57{
58	return 0;
59}
60static inline void unregister_cpu_notifier(struct notifier_block *nb)
61{
62}
63
64#endif /* CONFIG_SMP */
65extern struct sysdev_class cpu_sysdev_class;
66
67#ifdef CONFIG_HOTPLUG_CPU
68/* Stop CPUs going up and down. */
69extern void lock_cpu_hotplug(void);
70extern void unlock_cpu_hotplug(void);
71#define hotcpu_notifier(fn, pri) {				\
72	static struct notifier_block fn##_nb =			\
73		{ .notifier_call = fn, .priority = pri };	\
74	register_cpu_notifier(&fn##_nb);			\
75}
76#define register_hotcpu_notifier(nb)	register_cpu_notifier(nb)
77#define unregister_hotcpu_notifier(nb)	unregister_cpu_notifier(nb)
78int cpu_down(unsigned int cpu);
79#define cpu_is_offline(cpu) unlikely(!cpu_online(cpu))
80#else
81#define lock_cpu_hotplug()	do { } while (0)
82#define unlock_cpu_hotplug()	do { } while (0)
83#define lock_cpu_hotplug_interruptible() 0
84#define hotcpu_notifier(fn, pri)	do { } while (0)
85#define register_hotcpu_notifier(nb)	do { } while (0)
86#define unregister_hotcpu_notifier(nb)	do { } while (0)
87
88/* CPUs don't go offline once they're online w/o CONFIG_HOTPLUG_CPU */
89static inline int cpu_is_offline(int cpu) { return 0; }
90#endif
91
92#endif /* _LINUX_CPU_H_ */
93