/* * drivers/base/cpu.c - basic CPU class support */ #include <linux/sysdev.h> #include <linux/module.h> #include <linux/init.h> #include <linux/sched.h> #include <linux/cpu.h> #include <linux/topology.h> #include <linux/device.h> #include <linux/node.h> #include "base.h" struct sysdev_class cpu_sysdev_class = { .name = "cpu", }; EXPORT_SYMBOL(cpu_sysdev_class); static struct sys_device *cpu_sys_devices[NR_CPUS]; #ifdef CONFIG_HOTPLUG_CPU static ssize_t show_online(struct sys_device *dev, char *buf) { struct cpu *cpu = container_of(dev, struct cpu, sysdev); return sprintf(buf, "%u\n", !!cpu_online(cpu->sysdev.id)); } static ssize_t store_online(struct sys_device *dev, const char *buf, size_t count) { struct cpu *cpu = container_of(dev, struct cpu, sysdev); ssize_t ret; switch (buf[0]) { case '0': ret = cpu_down(cpu->sysdev.id); if (!ret) kobject_uevent(&dev->kobj, KOBJ_OFFLINE); break; case '1': ret = cpu_up(cpu->sysdev.id); if (!ret) kobject_uevent(&dev->kobj, KOBJ_ONLINE); break; default: ret = -EINVAL; } if (ret >= 0) ret = count; return ret; } static SYSDEV_ATTR(online, 0644, show_online, store_online); static void __devinit register_cpu_control(struct cpu *cpu) { sysdev_create_file(&cpu->sysdev, &attr_online); } void unregister_cpu(struct cpu *cpu) { int logical_cpu = cpu->sysdev.id; unregister_cpu_under_node(logical_cpu, cpu_to_node(logical_cpu)); sysdev_remove_file(&cpu->sysdev, &attr_online); sysdev_unregister(&cpu->sysdev); cpu_sys_devices[logical_cpu] = NULL; return; } #else /* ... !CONFIG_HOTPLUG_CPU */ static inline void register_cpu_control(struct cpu *cpu) { } #endif /* CONFIG_HOTPLUG_CPU */ #ifdef CONFIG_KEXEC #include <linux/kexec.h> static ssize_t show_crash_notes(struct sys_device *dev, char *buf) { struct cpu *cpu = container_of(dev, struct cpu, sysdev); ssize_t rc; unsigned long long addr; int cpunum; cpunum = cpu->sysdev.id; /* * Might be reading other cpu's data based on which cpu read thread * has been scheduled. But cpu data (memory) is allocated once during * boot up and this data does not change there after. Hence this * operation should be safe. No locking required. */ addr = __pa(per_cpu_ptr(crash_notes, cpunum)); rc = sprintf(buf, "%Lx\n", addr); return rc; } static SYSDEV_ATTR(crash_notes, 0400, show_crash_notes, NULL); #endif /* * register_cpu - Setup a sysfs device for a CPU. * @cpu - cpu->hotpluggable field set to 1 will generate a control file in * sysfs for this CPU. * @num - CPU number to use when creating the device. * * Initialize and register the CPU device. */ int __cpuinit register_cpu(struct cpu *cpu, int num) { int error; cpu->node_id = cpu_to_node(num); cpu->sysdev.id = num; cpu->sysdev.cls = &cpu_sysdev_class; error = sysdev_register(&cpu->sysdev); if (!error && cpu->hotpluggable) register_cpu_control(cpu); if (!error) cpu_sys_devices[num] = &cpu->sysdev; if (!error) register_cpu_under_node(num, cpu_to_node(num)); #ifdef CONFIG_KEXEC if (!error) error = sysdev_create_file(&cpu->sysdev, &attr_crash_notes); #endif return error; } struct sys_device *get_cpu_sysdev(unsigned cpu) { if (cpu < NR_CPUS) return cpu_sys_devices[cpu]; else return NULL; } EXPORT_SYMBOL_GPL(get_cpu_sysdev); int __init cpu_dev_init(void) { int err; err = sysdev_class_register(&cpu_sysdev_class); #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) if (!err) err = sched_create_sysfs_power_savings_entries(&cpu_sysdev_class); #endif return err; }