/* * 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 <linux/gfp.h> #include "base.h" static struct sysdev_class_attribute *cpu_sysdev_class_attrs[]; struct sysdev_class cpu_sysdev_class = { .name = "cpu", .attrs = cpu_sysdev_class_attrs, }; EXPORT_SYMBOL(cpu_sysdev_class); static DEFINE_PER_CPU(struct sys_device *, cpu_sys_devices); #ifdef CONFIG_HOTPLUG_CPU static ssize_t show_online(struct sys_device *dev, struct sysdev_attribute *attr, char *buf) { struct cpu *cpu = container_of(dev, struct cpu, sysdev); return sprintf(buf, "%u\n", !!cpu_online(cpu->sysdev.id)); } static ssize_t __ref store_online(struct sys_device *dev, struct sysdev_attribute *attr, const char *buf, size_t count) { struct cpu *cpu = container_of(dev, struct cpu, sysdev); ssize_t ret; cpu_hotplug_driver_lock(); 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; } cpu_hotplug_driver_unlock(); if (ret >= 0) ret = count; return ret; } static SYSDEV_ATTR(online, 0644, show_online, store_online); static void __cpuinit 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); per_cpu(cpu_sys_devices, logical_cpu) = NULL; return; } #ifdef CONFIG_ARCH_CPU_PROBE_RELEASE static ssize_t cpu_probe_store(struct sysdev_class *class, struct sysdev_class_attribute *attr, const char *buf, size_t count) { return arch_cpu_probe(buf, count); } static ssize_t cpu_release_store(struct sysdev_class *class, struct sysdev_class_attribute *attr, const char *buf, size_t count) { return arch_cpu_release(buf, count); } static SYSDEV_CLASS_ATTR(probe, S_IWUSR, NULL, cpu_probe_store); static SYSDEV_CLASS_ATTR(release, S_IWUSR, NULL, cpu_release_store); #endif /* CONFIG_ARCH_CPU_PROBE_RELEASE */ #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, struct sysdev_attribute *attr, 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 = per_cpu_ptr_to_phys(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 /* * Print cpu online, possible, present, and system maps */ struct cpu_attr { struct sysdev_class_attribute attr; const struct cpumask *const * const map; }; static ssize_t show_cpus_attr(struct sysdev_class *class, struct sysdev_class_attribute *attr, char *buf) { struct cpu_attr *ca = container_of(attr, struct cpu_attr, attr); int n = cpulist_scnprintf(buf, PAGE_SIZE-2, *(ca->map)); buf[n++] = '\n'; buf[n] = '\0'; return n; } #define _CPU_ATTR(name, map) \ { _SYSDEV_CLASS_ATTR(name, 0444, show_cpus_attr, NULL), map } /* Keep in sync with cpu_sysdev_class_attrs */ static struct cpu_attr cpu_attrs[] = { _CPU_ATTR(online, &cpu_online_mask), _CPU_ATTR(possible, &cpu_possible_mask), _CPU_ATTR(present, &cpu_present_mask), }; /* * Print values for NR_CPUS and offlined cpus */ static ssize_t print_cpus_kernel_max(struct sysdev_class *class, struct sysdev_class_attribute *attr, char *buf) { int n = snprintf(buf, PAGE_SIZE-2, "%d\n", NR_CPUS - 1); return n; } static SYSDEV_CLASS_ATTR(kernel_max, 0444, print_cpus_kernel_max, NULL); /* arch-optional setting to enable display of offline cpus >= nr_cpu_ids */ unsigned int total_cpus; static ssize_t print_cpus_offline(struct sysdev_class *class, struct sysdev_class_attribute *attr, char *buf) { int n = 0, len = PAGE_SIZE-2; cpumask_var_t offline; /* display offline cpus < nr_cpu_ids */ if (!alloc_cpumask_var(&offline, GFP_KERNEL)) return -ENOMEM; cpumask_andnot(offline, cpu_possible_mask, cpu_online_mask); n = cpulist_scnprintf(buf, len, offline); free_cpumask_var(offline); /* display offline cpus >= nr_cpu_ids */ if (total_cpus && nr_cpu_ids < total_cpus) { if (n && n < len) buf[n++] = ','; if (nr_cpu_ids == total_cpus-1) n += snprintf(&buf[n], len - n, "%d", nr_cpu_ids); else n += snprintf(&buf[n], len - n, "%d-%d", nr_cpu_ids, total_cpus-1); } n += snprintf(&buf[n], len - n, "\n"); return n; } static SYSDEV_CLASS_ATTR(offline, 0444, print_cpus_offline, NULL); /* * 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) per_cpu(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_cpu_ids && cpu_possible(cpu)) return per_cpu(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; } static struct sysdev_class_attribute *cpu_sysdev_class_attrs[] = { #ifdef CONFIG_ARCH_CPU_PROBE_RELEASE &attr_probe, &attr_release, #endif &cpu_attrs[0].attr, &cpu_attrs[1].attr, &cpu_attrs[2].attr, &attr_kernel_max, &attr_offline, NULL };