2 * drivers/base/cpu.c - basic CPU class support
5 #include <linux/sysdev.h>
6 #include <linux/module.h>
7 #include <linux/init.h>
8 #include <linux/sched.h>
10 #include <linux/topology.h>
11 #include <linux/device.h>
12 #include <linux/node.h>
16 struct sysdev_class cpu_sysdev_class = {
19 EXPORT_SYMBOL(cpu_sysdev_class);
21 static DEFINE_PER_CPU(struct sys_device *, cpu_sys_devices);
23 #ifdef CONFIG_HOTPLUG_CPU
24 static ssize_t show_online(struct sys_device *dev, struct sysdev_attribute *attr,
27 struct cpu *cpu = container_of(dev, struct cpu, sysdev);
29 return sprintf(buf, "%u\n", !!cpu_online(cpu->sysdev.id));
32 static ssize_t __ref store_online(struct sys_device *dev, struct sysdev_attribute *attr,
33 const char *buf, size_t count)
35 struct cpu *cpu = container_of(dev, struct cpu, sysdev);
38 cpu_hotplug_driver_lock();
41 ret = cpu_down(cpu->sysdev.id);
43 kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
46 ret = cpu_up(cpu->sysdev.id);
48 kobject_uevent(&dev->kobj, KOBJ_ONLINE);
53 cpu_hotplug_driver_unlock();
59 static SYSDEV_ATTR(online, 0644, show_online, store_online);
61 static void __cpuinit register_cpu_control(struct cpu *cpu)
63 sysdev_create_file(&cpu->sysdev, &attr_online);
65 void unregister_cpu(struct cpu *cpu)
67 int logical_cpu = cpu->sysdev.id;
69 unregister_cpu_under_node(logical_cpu, cpu_to_node(logical_cpu));
71 sysdev_remove_file(&cpu->sysdev, &attr_online);
73 sysdev_unregister(&cpu->sysdev);
74 per_cpu(cpu_sys_devices, logical_cpu) = NULL;
78 #ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
79 static ssize_t cpu_probe_store(struct class *class, const char *buf,
82 return arch_cpu_probe(buf, count);
85 static ssize_t cpu_release_store(struct class *class, const char *buf,
88 return arch_cpu_release(buf, count);
91 static CLASS_ATTR(probe, S_IWUSR, NULL, cpu_probe_store);
92 static CLASS_ATTR(release, S_IWUSR, NULL, cpu_release_store);
94 int __init cpu_probe_release_init(void)
98 rc = sysfs_create_file(&cpu_sysdev_class.kset.kobj,
99 &class_attr_probe.attr);
101 rc = sysfs_create_file(&cpu_sysdev_class.kset.kobj,
102 &class_attr_release.attr);
106 device_initcall(cpu_probe_release_init);
107 #endif /* CONFIG_ARCH_CPU_PROBE_RELEASE */
109 #else /* ... !CONFIG_HOTPLUG_CPU */
110 static inline void register_cpu_control(struct cpu *cpu)
113 #endif /* CONFIG_HOTPLUG_CPU */
116 #include <linux/kexec.h>
118 static ssize_t show_crash_notes(struct sys_device *dev, struct sysdev_attribute *attr,
121 struct cpu *cpu = container_of(dev, struct cpu, sysdev);
123 unsigned long long addr;
126 cpunum = cpu->sysdev.id;
129 * Might be reading other cpu's data based on which cpu read thread
130 * has been scheduled. But cpu data (memory) is allocated once during
131 * boot up and this data does not change there after. Hence this
132 * operation should be safe. No locking required.
134 addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpunum));
135 rc = sprintf(buf, "%Lx\n", addr);
138 static SYSDEV_ATTR(crash_notes, 0400, show_crash_notes, NULL);
142 * Print cpu online, possible, present, and system maps
146 struct sysdev_class_attribute attr;
147 const struct cpumask *const * const map;
150 static ssize_t show_cpus_attr(struct sysdev_class *class,
151 struct sysdev_class_attribute *attr,
154 struct cpu_attr *ca = container_of(attr, struct cpu_attr, attr);
155 int n = cpulist_scnprintf(buf, PAGE_SIZE-2, *(ca->map));
162 #define _CPU_ATTR(name, map) \
163 { _SYSDEV_CLASS_ATTR(name, 0444, show_cpus_attr, NULL), map }
165 static struct cpu_attr cpu_attrs[] = {
166 _CPU_ATTR(online, &cpu_online_mask),
167 _CPU_ATTR(possible, &cpu_possible_mask),
168 _CPU_ATTR(present, &cpu_present_mask),
172 * Print values for NR_CPUS and offlined cpus
174 static ssize_t print_cpus_kernel_max(struct sysdev_class *class,
175 struct sysdev_class_attribute *attr, char *buf)
177 int n = snprintf(buf, PAGE_SIZE-2, "%d\n", NR_CPUS - 1);
180 static SYSDEV_CLASS_ATTR(kernel_max, 0444, print_cpus_kernel_max, NULL);
182 /* arch-optional setting to enable display of offline cpus >= nr_cpu_ids */
183 unsigned int total_cpus;
185 static ssize_t print_cpus_offline(struct sysdev_class *class,
186 struct sysdev_class_attribute *attr, char *buf)
188 int n = 0, len = PAGE_SIZE-2;
189 cpumask_var_t offline;
191 /* display offline cpus < nr_cpu_ids */
192 if (!alloc_cpumask_var(&offline, GFP_KERNEL))
194 cpumask_complement(offline, cpu_online_mask);
195 n = cpulist_scnprintf(buf, len, offline);
196 free_cpumask_var(offline);
198 /* display offline cpus >= nr_cpu_ids */
199 if (total_cpus && nr_cpu_ids < total_cpus) {
203 if (nr_cpu_ids == total_cpus-1)
204 n += snprintf(&buf[n], len - n, "%d", nr_cpu_ids);
206 n += snprintf(&buf[n], len - n, "%d-%d",
207 nr_cpu_ids, total_cpus-1);
210 n += snprintf(&buf[n], len - n, "\n");
213 static SYSDEV_CLASS_ATTR(offline, 0444, print_cpus_offline, NULL);
215 static struct sysdev_class_attribute *cpu_state_attr[] = {
223 static int cpu_states_init(void)
228 for (i = 0; i < ARRAY_SIZE(cpu_state_attr); i++) {
230 ret = sysdev_class_create_file(&cpu_sysdev_class,
239 * register_cpu - Setup a sysfs device for a CPU.
240 * @cpu - cpu->hotpluggable field set to 1 will generate a control file in
241 * sysfs for this CPU.
242 * @num - CPU number to use when creating the device.
244 * Initialize and register the CPU device.
246 int __cpuinit register_cpu(struct cpu *cpu, int num)
249 cpu->node_id = cpu_to_node(num);
250 cpu->sysdev.id = num;
251 cpu->sysdev.cls = &cpu_sysdev_class;
253 error = sysdev_register(&cpu->sysdev);
255 if (!error && cpu->hotpluggable)
256 register_cpu_control(cpu);
258 per_cpu(cpu_sys_devices, num) = &cpu->sysdev;
260 register_cpu_under_node(num, cpu_to_node(num));
264 error = sysdev_create_file(&cpu->sysdev, &attr_crash_notes);
269 struct sys_device *get_cpu_sysdev(unsigned cpu)
271 if (cpu < nr_cpu_ids && cpu_possible(cpu))
272 return per_cpu(cpu_sys_devices, cpu);
276 EXPORT_SYMBOL_GPL(get_cpu_sysdev);
278 int __init cpu_dev_init(void)
282 err = sysdev_class_register(&cpu_sysdev_class);
284 err = cpu_states_init();
286 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
288 err = sched_create_sysfs_power_savings_entries(&cpu_sysdev_class);