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 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 #ifdef CONFIG_HOTPLUG_CPU 36 extern void unregister_cpu(struct cpu *, struct node *); 37 #endif 38 struct notifier_block; 39 40 #ifdef CONFIG_SMP 41 /* Need to know about CPUs going up/down? */ 42 extern int register_cpu_notifier(struct notifier_block *nb); 43 extern void unregister_cpu_notifier(struct notifier_block *nb); 44 45 int cpu_up(unsigned int cpu); 46 47 #else 48 49 static inline int register_cpu_notifier(struct notifier_block *nb) 50 { 51 return 0; 52 } 53 static inline void unregister_cpu_notifier(struct notifier_block *nb) 54 { 55 } 56 57 #endif /* CONFIG_SMP */ 58 extern struct sysdev_class cpu_sysdev_class; 59 60 #ifdef CONFIG_HOTPLUG_CPU 61 /* Stop CPUs going up and down. */ 62 extern 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 } 71 int 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 */ 80 static inline int cpu_is_offline(int cpu) { return 0; } 81 #endif 82 83 #endif /* _LINUX_CPU_H_ */ 84