/* * CPU subsystem support */ #include <linux/kernel.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 <linux/slab.h> #include <linux/percpu.h> #include "base.h" struct bus_type cpu_subsys = { .name = "cpu", .dev_name = "cpu", }; EXPORT_SYMBOL_GPL(cpu_subsys); static DEFINE_PER_CPU(struct device *, cpu_sys_devices); #ifdef CONFIG_HOTPLUG_CPU static ssize_t show_online(struct device *dev, struct device_attribute *attr, char *buf) { struct cpu *cpu = container_of(dev, struct cpu, dev); return sprintf(buf, "%u\n", !!cpu_online(cpu->dev.id)); } static ssize_t __ref store_online(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { struct cpu *cpu = container_of(dev, struct cpu, dev); ssize_t ret; cpu_hotplug_driver_lock(); switch (buf[0]) { case '0': ret = cpu_down(cpu->dev.id); if (!ret) kobject_uevent(&dev->kobj, KOBJ_OFFLINE); break; case '1': ret = cpu_up(cpu->dev.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 DEVICE_ATTR(online, 0644, show_online, store_online); static void __cpuinit register_cpu_control(struct cpu *cpu) { device_create_file(&cpu->dev, &dev_attr_online); } void unregister_cpu(struct cpu *cpu) { int logical_cpu = cpu->dev.id; unregister_cpu_under_node(logical_cpu, cpu_to_node(logical_cpu)); device_remove_file(&cpu->dev, &dev_attr_online); device_unregister(&cpu->dev); per_cpu(cpu_sys_devices, logical_cpu) = NULL; return; } #ifdef CONFIG_ARCH_CPU_PROBE_RELEASE static ssize_t cpu_probe_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { return arch_cpu_probe(buf, count); } static ssize_t cpu_release_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { return arch_cpu_release(buf, count); } static DEVICE_ATTR(probe, S_IWUSR, NULL, cpu_probe_store); static DEVICE_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 device *dev, struct device_attribute *attr, char *buf) { struct cpu *cpu = container_of(dev, struct cpu, dev); ssize_t rc; unsigned long long addr; int cpunum; cpunum = cpu->dev.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 DEVICE_ATTR(crash_notes, 0400, show_crash_notes, NULL); #endif /* * Print cpu online, possible, present, and system maps */ struct cpu_attr { struct device_attribute attr; const struct cpumask *const * const map; }; static ssize_t show_cpus_attr(struct device *dev, struct device_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) \ { __ATTR(name, 0444, show_cpus_attr, NULL), map } /* Keep in sync with cpu_subsys_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 device *dev, struct device_attribute *attr, char *buf) { int n = snprintf(buf, PAGE_SIZE-2, "%d\n", NR_CPUS - 1); return n; } static DEVICE_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 device *dev, struct device_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 DEVICE_ATTR(offline, 0444, print_cpus_offline, NULL); static void cpu_device_release(struct device *dev) { /* * This is an empty function to prevent the driver core from spitting a * warning at us. Yes, I know this is directly opposite of what the * documentation for the driver core and kobjects say, and the author * of this code has already been publically ridiculed for doing * something as foolish as this. However, at this point in time, it is * the only way to handle the issue of statically allocated cpu * devices. The different architectures will have their cpu device * code reworked to properly handle this in the near future, so this * function will then be changed to correctly free up the memory held * by the cpu device. * * Never copy this way of doing things, or you too will be made fun of * on the linux-kerenl list, you have been warned. */ } /* * 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); memset(&cpu->dev, 0x00, sizeof(struct device)); cpu->dev.id = num; cpu->dev.bus = &cpu_subsys; cpu->dev.release = cpu_device_release; #ifdef CONFIG_ARCH_HAS_CPU_AUTOPROBE cpu->dev.bus->uevent = arch_cpu_uevent; #endif error = device_register(&cpu->dev); if (!error && cpu->hotpluggable) register_cpu_control(cpu); if (!error) per_cpu(cpu_sys_devices, num) = &cpu->dev; if (!error) register_cpu_under_node(num, cpu_to_node(num)); #ifdef CONFIG_KEXEC if (!error) error = device_create_file(&cpu->dev, &dev_attr_crash_notes); #endif return error; } struct device *get_cpu_device(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_device); #ifdef CONFIG_ARCH_HAS_CPU_AUTOPROBE static DEVICE_ATTR(modalias, 0444, arch_print_cpu_modalias, NULL); #endif static struct attribute *cpu_root_attrs[] = { #ifdef CONFIG_ARCH_CPU_PROBE_RELEASE &dev_attr_probe.attr, &dev_attr_release.attr, #endif &cpu_attrs[0].attr.attr, &cpu_attrs[1].attr.attr, &cpu_attrs[2].attr.attr, &dev_attr_kernel_max.attr, &dev_attr_offline.attr, #ifdef CONFIG_ARCH_HAS_CPU_AUTOPROBE &dev_attr_modalias.attr, #endif NULL }; static struct attribute_group cpu_root_attr_group = { .attrs = cpu_root_attrs, }; static const struct attribute_group *cpu_root_attr_groups[] = { &cpu_root_attr_group, NULL, }; bool cpu_is_hotpluggable(unsigned cpu) { struct device *dev = get_cpu_device(cpu); return dev && container_of(dev, struct cpu, dev)->hotpluggable; } EXPORT_SYMBOL_GPL(cpu_is_hotpluggable); #ifdef CONFIG_GENERIC_CPU_DEVICES static DEFINE_PER_CPU(struct cpu, cpu_devices); #endif static void __init cpu_dev_register_generic(void) { #ifdef CONFIG_GENERIC_CPU_DEVICES int i; for_each_possible_cpu(i) { if (register_cpu(&per_cpu(cpu_devices, i), i)) panic("Failed to register CPU device"); } #endif } void __init cpu_dev_init(void) { if (subsys_system_register(&cpu_subsys, cpu_root_attr_groups)) panic("Failed to register CPU subsystem"); cpu_dev_register_generic(); }