linux-stable/drivers/base/cpu.c
Jan Beulich cdc6e3d396 drivers/base/cpu.c: fix the output from /sys/devices/system/cpu/offline
Without CONFIG_CPUMASK_OFFSTACK, simply inverting cpu_online_mask leads
to CPUs beyond nr_cpu_ids to be displayed twice and CPUs not even
possible to be displayed as offline.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-05-21 09:37:28 -07:00

274 lines
6.7 KiB
C

/*
* 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
};