xref: /openbmc/linux/include/linux/cpu.h (revision e868d61272caa648214046a096e5a6bfc068dc8c)
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 #include <linux/mutex.h>
28 
29 struct cpu {
30 	int node_id;		/* The node which contains the CPU */
31 	int hotpluggable;	/* creates sysfs control file if hotpluggable */
32 	struct sys_device sysdev;
33 };
34 
35 extern int register_cpu(struct cpu *cpu, int num);
36 extern struct sys_device *get_cpu_sysdev(unsigned cpu);
37 
38 extern int cpu_add_sysdev_attr(struct sysdev_attribute *attr);
39 extern void cpu_remove_sysdev_attr(struct sysdev_attribute *attr);
40 
41 extern int cpu_add_sysdev_attr_group(struct attribute_group *attrs);
42 extern void cpu_remove_sysdev_attr_group(struct attribute_group *attrs);
43 
44 extern struct sysdev_attribute attr_sched_mc_power_savings;
45 extern struct sysdev_attribute attr_sched_smt_power_savings;
46 extern int sched_create_sysfs_power_savings_entries(struct sysdev_class *cls);
47 
48 #ifdef CONFIG_HOTPLUG_CPU
49 extern void unregister_cpu(struct cpu *cpu);
50 #endif
51 struct notifier_block;
52 
53 #ifdef CONFIG_SMP
54 /* Need to know about CPUs going up/down? */
55 #ifdef CONFIG_HOTPLUG_CPU
56 extern int register_cpu_notifier(struct notifier_block *nb);
57 extern void unregister_cpu_notifier(struct notifier_block *nb);
58 #else
59 
60 #ifndef MODULE
61 extern int register_cpu_notifier(struct notifier_block *nb);
62 #else
63 static inline int register_cpu_notifier(struct notifier_block *nb)
64 {
65 	return 0;
66 }
67 #endif
68 
69 static inline void unregister_cpu_notifier(struct notifier_block *nb)
70 {
71 }
72 #endif
73 
74 int cpu_up(unsigned int cpu);
75 
76 #else
77 
78 static inline int register_cpu_notifier(struct notifier_block *nb)
79 {
80 	return 0;
81 }
82 static inline void unregister_cpu_notifier(struct notifier_block *nb)
83 {
84 }
85 
86 #endif /* CONFIG_SMP */
87 extern struct sysdev_class cpu_sysdev_class;
88 
89 #ifdef CONFIG_HOTPLUG_CPU
90 /* Stop CPUs going up and down. */
91 
92 static inline void cpuhotplug_mutex_lock(struct mutex *cpu_hp_mutex)
93 {
94 	mutex_lock(cpu_hp_mutex);
95 }
96 
97 static inline void cpuhotplug_mutex_unlock(struct mutex *cpu_hp_mutex)
98 {
99 	mutex_unlock(cpu_hp_mutex);
100 }
101 
102 extern void lock_cpu_hotplug(void);
103 extern void unlock_cpu_hotplug(void);
104 #define hotcpu_notifier(fn, pri) {				\
105 	static struct notifier_block fn##_nb =			\
106 		{ .notifier_call = fn, .priority = pri };	\
107 	register_cpu_notifier(&fn##_nb);			\
108 }
109 #define register_hotcpu_notifier(nb)	register_cpu_notifier(nb)
110 #define unregister_hotcpu_notifier(nb)	unregister_cpu_notifier(nb)
111 int cpu_down(unsigned int cpu);
112 #define cpu_is_offline(cpu) unlikely(!cpu_online(cpu))
113 
114 #else		/* CONFIG_HOTPLUG_CPU */
115 
116 static inline void cpuhotplug_mutex_lock(struct mutex *cpu_hp_mutex)
117 { }
118 static inline void cpuhotplug_mutex_unlock(struct mutex *cpu_hp_mutex)
119 { }
120 
121 #define lock_cpu_hotplug()	do { } while (0)
122 #define unlock_cpu_hotplug()	do { } while (0)
123 #define lock_cpu_hotplug_interruptible() 0
124 #define hotcpu_notifier(fn, pri)	do { (void)(fn); } while (0)
125 #define register_hotcpu_notifier(nb)	do { (void)(nb); } while (0)
126 #define unregister_hotcpu_notifier(nb)	do { (void)(nb); } while (0)
127 
128 /* CPUs don't go offline once they're online w/o CONFIG_HOTPLUG_CPU */
129 static inline int cpu_is_offline(int cpu) { return 0; }
130 #endif		/* CONFIG_HOTPLUG_CPU */
131 
132 #ifdef CONFIG_SUSPEND_SMP
133 extern int suspend_cpu_hotplug;
134 
135 extern int disable_nonboot_cpus(void);
136 extern void enable_nonboot_cpus(void);
137 #else
138 #define suspend_cpu_hotplug	0
139 
140 static inline int disable_nonboot_cpus(void) { return 0; }
141 static inline void enable_nonboot_cpus(void) {}
142 #endif
143 
144 #endif /* _LINUX_CPU_H_ */
145