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 28 struct 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 34 extern int register_cpu(struct cpu *, int, struct node *); 35 extern struct sys_device *get_cpu_sysdev(int cpu); 36 #ifdef CONFIG_HOTPLUG_CPU 37 extern void unregister_cpu(struct cpu *, struct node *); 38 #endif 39 struct notifier_block; 40 41 #ifdef CONFIG_SMP 42 /* Need to know about CPUs going up/down? */ 43 extern int register_cpu_notifier(struct notifier_block *nb); 44 extern void unregister_cpu_notifier(struct notifier_block *nb); 45 46 int cpu_up(unsigned int cpu); 47 48 #else 49 50 static inline int register_cpu_notifier(struct notifier_block *nb) 51 { 52 return 0; 53 } 54 static inline void unregister_cpu_notifier(struct notifier_block *nb) 55 { 56 } 57 58 #endif /* CONFIG_SMP */ 59 extern struct sysdev_class cpu_sysdev_class; 60 61 #ifdef CONFIG_HOTPLUG_CPU 62 /* Stop CPUs going up and down. */ 63 extern struct semaphore cpucontrol; 64 #define lock_cpu_hotplug() down(&cpucontrol) 65 #define unlock_cpu_hotplug() up(&cpucontrol) 66 #define lock_cpu_hotplug_interruptible() down_interruptible(&cpucontrol) 67 #define hotcpu_notifier(fn, pri) { \ 68 static struct notifier_block fn##_nb = \ 69 { .notifier_call = fn, .priority = pri }; \ 70 register_cpu_notifier(&fn##_nb); \ 71 } 72 int cpu_down(unsigned int cpu); 73 extern int __attribute__((weak)) smp_prepare_cpu(int cpu); 74 #define cpu_is_offline(cpu) unlikely(!cpu_online(cpu)) 75 #else 76 #define lock_cpu_hotplug() do { } while (0) 77 #define unlock_cpu_hotplug() do { } while (0) 78 #define lock_cpu_hotplug_interruptible() 0 79 #define hotcpu_notifier(fn, pri) 80 81 /* CPUs don't go offline once they're online w/o CONFIG_HOTPLUG_CPU */ 82 static inline int cpu_is_offline(int cpu) { return 0; } 83 #endif 84 85 #endif /* _LINUX_CPU_H_ */ 86