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/*
* 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 DEFINE_PER_CPU(struct sys_device *, cpu_sys_devices);
#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 __ref 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 __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;
}
#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
/*
* Print cpu online, possible, present, and system maps
*/
static ssize_t print_cpus_map(char *buf, cpumask_t *map)
{
int n = cpulist_scnprintf(buf, PAGE_SIZE-2, *map);
buf[n++] = '\n';
buf[n] = '\0';
return n;
}
#define print_cpus_func(type) \
static ssize_t print_cpus_##type(struct sysdev_class *class, char *buf) \
{ \
return print_cpus_map(buf, &cpu_##type##_map); \
} \
static struct sysdev_class_attribute attr_##type##_map = \
_SYSDEV_CLASS_ATTR(type, 0444, print_cpus_##type, NULL)
print_cpus_func(online);
print_cpus_func(possible);
print_cpus_func(present);
static struct sysdev_class_attribute *cpu_state_attr[] = {
&attr_online_map,
&attr_possible_map,
&attr_present_map,
};
static int cpu_states_init(void)
{
int i;
int err = 0;
for (i = 0; i < ARRAY_SIZE(cpu_state_attr); i++) {
int ret;
ret = sysdev_class_create_file(&cpu_sysdev_class,
cpu_state_attr[i]);
if (!err)
err = ret;
}
return err;
}
/*
* 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 (!err)
err = cpu_states_init();
#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
if (!err)
err = sched_create_sysfs_power_savings_entries(&cpu_sysdev_class);
#endif
return err;
}
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