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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/cpu.h>
#include <linux/topology.h>
#include <linux/device.h>
#include "base.h"
struct sysdev_class cpu_sysdev_class = {
set_kset_name("cpu"),
};
EXPORT_SYMBOL(cpu_sysdev_class);
static struct sys_device *cpu_sys_devices[NR_CPUS];
#ifdef CONFIG_HOTPLUG_CPU
int __attribute__((weak)) smp_prepare_cpu (int cpu)
{
return 0;
}
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 = smp_prepare_cpu(cpu->sysdev.id);
if (!ret)
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, 0600, 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, struct node *root)
{
int logical_cpu = cpu->sysdev.id;
if (root)
sysfs_remove_link(&root->sysdev.kobj,
kobject_name(&cpu->sysdev.kobj));
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 driverfs device for a CPU.
* @cpu - Callers can set the cpu->no_control field to 1, to indicate not to
* 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 __devinit register_cpu(struct cpu *cpu, int num, struct node *root)
{
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 && root)
error = sysfs_create_link(&root->sysdev.kobj,
&cpu->sysdev.kobj,
kobject_name(&cpu->sysdev.kobj));
if (!error && !cpu->no_control)
register_cpu_control(cpu);
if (!error)
cpu_sys_devices[num] = &cpu->sysdev;
#ifdef CONFIG_KEXEC
if (!error)
error = sysdev_create_file(&cpu->sysdev, &attr_crash_notes);
#endif
return error;
}
struct sys_device *get_cpu_sysdev(int 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)
{
return sysdev_class_register(&cpu_sysdev_class);
}
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