[linux.git] / drivers / base / cpu.c

/*
 * 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();
}
Commit	Line	Data
1da177e4	1	/*
8a25a2fd	2	* CPU subsystem support
1da177e4 LT	3	*/
1da177e4 LT	4
024f7846	5	#include <linux/kernel.h>
1da177e4 LT	6	#include <linux/module.h>
1da177e4 LT	7	#include <linux/init.h>
f6a57033	8	#include <linux/sched.h>
1da177e4 LT	9	#include <linux/cpu.h>
	10	#include <linux/topology.h>
	11	#include <linux/device.h>
76b67ed9	12	#include <linux/node.h>
5a0e3ad6	13	#include <linux/gfp.h>
fad12ac8	14	#include <linux/slab.h>
9f13a1fd	15	#include <linux/percpu.h>
1da177e4	16
a1bdc7aa	17	#include "base.h"
1da177e4	18
8a25a2fd	19	struct bus_type cpu_subsys = {
af5ca3f4	20	.name = "cpu",
8a25a2fd	21	.dev_name = "cpu",
1da177e4	22	};
8a25a2fd	23	EXPORT_SYMBOL_GPL(cpu_subsys);
1da177e4	24
8a25a2fd	25	static DEFINE_PER_CPU(struct device *, cpu_sys_devices);
ad74557a	26
1da177e4	27	#ifdef CONFIG_HOTPLUG_CPU
8a25a2fd KS	28	static ssize_t show_online(struct device *dev,
8a25a2fd KS	29	struct device_attribute *attr,
4a0b2b4d	30	char *buf)
1da177e4	31	{
8a25a2fd	32	struct cpu *cpu = container_of(dev, struct cpu, dev);
1da177e4	33
8a25a2fd	34	return sprintf(buf, "%u\n", !!cpu_online(cpu->dev.id));
1da177e4 LT	35	}
1da177e4 LT	36
8a25a2fd KS	37	static ssize_t __ref store_online(struct device *dev,
	38	struct device_attribute *attr,
	39	const char *buf, size_t count)
1da177e4	40	{
8a25a2fd	41	struct cpu *cpu = container_of(dev, struct cpu, dev);
1da177e4 LT	42	ssize_t ret;
1da177e4 LT	43
51badebd	44	cpu_hotplug_driver_lock();
1da177e4 LT	45	switch (buf[0]) {
1da177e4 LT	46	case '0':
8a25a2fd	47	ret = cpu_down(cpu->dev.id);
1da177e4	48	if (!ret)
312c004d	49	kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
1da177e4 LT	50	break;
1da177e4 LT	51	case '1':
8a25a2fd	52	ret = cpu_up(cpu->dev.id);
fb69c390	53	if (!ret)
312c004d	54	kobject_uevent(&dev->kobj, KOBJ_ONLINE);
1da177e4 LT	55	break;
	56	default:
	57	ret = -EINVAL;
	58	}
51badebd	59	cpu_hotplug_driver_unlock();
1da177e4 LT	60
	61	if (ret >= 0)
	62	ret = count;
	63	return ret;
	64	}
8a25a2fd	65	static DEVICE_ATTR(online, 0644, show_online, store_online);
1da177e4	66
6c847402	67	static void __cpuinit register_cpu_control(struct cpu *cpu)
1da177e4	68	{
8a25a2fd	69	device_create_file(&cpu->dev, &dev_attr_online);
1da177e4	70	}
76b67ed9	71	void unregister_cpu(struct cpu *cpu)
1da177e4	72	{
8a25a2fd	73	int logical_cpu = cpu->dev.id;
1da177e4	74
76b67ed9 KH	75	unregister_cpu_under_node(logical_cpu, cpu_to_node(logical_cpu));
76b67ed9 KH	76
8a25a2fd	77	device_remove_file(&cpu->dev, &dev_attr_online);
1da177e4	78
8a25a2fd	79	device_unregister(&cpu->dev);
e37d05da	80	per_cpu(cpu_sys_devices, logical_cpu) = NULL;
1da177e4 LT	81	return;
1da177e4 LT	82	}
12633e80 NF	83
12633e80 NF	84	#ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
8a25a2fd KS	85	static ssize_t cpu_probe_store(struct device *dev,
8a25a2fd KS	86	struct device_attribute *attr,
67fc233f	87	const char *buf,
12633e80 NF	88	size_t count)
	89	{
	90	return arch_cpu_probe(buf, count);
	91	}
	92
8a25a2fd KS	93	static ssize_t cpu_release_store(struct device *dev,
8a25a2fd KS	94	struct device_attribute *attr,
67fc233f	95	const char *buf,
12633e80 NF	96	size_t count)
	97	{
	98	return arch_cpu_release(buf, count);
	99	}
	100
8a25a2fd KS	101	static DEVICE_ATTR(probe, S_IWUSR, NULL, cpu_probe_store);
8a25a2fd KS	102	static DEVICE_ATTR(release, S_IWUSR, NULL, cpu_release_store);
12633e80 NF	103	#endif /* CONFIG_ARCH_CPU_PROBE_RELEASE */
12633e80 NF	104
1da177e4 LT	105	#else /* ... !CONFIG_HOTPLUG_CPU */
	106	static inline void register_cpu_control(struct cpu *cpu)
	107	{
	108	}
	109	#endif /* CONFIG_HOTPLUG_CPU */
	110
51be5606 VG	111	#ifdef CONFIG_KEXEC
	112	#include <linux/kexec.h>
	113
8a25a2fd	114	static ssize_t show_crash_notes(struct device dev, struct device_attribute attr,
4a0b2b4d	115	char *buf)
51be5606	116	{
8a25a2fd	117	struct cpu *cpu = container_of(dev, struct cpu, dev);
51be5606 VG	118	ssize_t rc;
	119	unsigned long long addr;
	120	int cpunum;
	121
8a25a2fd	122	cpunum = cpu->dev.id;
51be5606 VG	123
	124	/*
	125	* Might be reading other cpu's data based on which cpu read thread
	126	* has been scheduled. But cpu data (memory) is allocated once during
	127	* boot up and this data does not change there after. Hence this
	128	* operation should be safe. No locking required.
	129	*/
3b034b0d	130	addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpunum));
51be5606	131	rc = sprintf(buf, "%Lx\n", addr);
51be5606 VG	132	return rc;
51be5606 VG	133	}
8a25a2fd	134	static DEVICE_ATTR(crash_notes, 0400, show_crash_notes, NULL);
51be5606 VG	135	#endif
51be5606 VG	136
9d1fe323 MT	137	/*
	138	* Print cpu online, possible, present, and system maps
	139	*/
265d2e2e AK	140
265d2e2e AK	141	struct cpu_attr {
8a25a2fd	142	struct device_attribute attr;
265d2e2e AK	143	const struct cpumask const const map;
	144	};
	145
8a25a2fd KS	146	static ssize_t show_cpus_attr(struct device *dev,
8a25a2fd KS	147	struct device_attribute *attr,
265d2e2e	148	char *buf)
9d1fe323	149	{
265d2e2e AK	150	struct cpu_attr *ca = container_of(attr, struct cpu_attr, attr);
265d2e2e AK	151	int n = cpulist_scnprintf(buf, PAGE_SIZE-2, *(ca->map));
9d1fe323 MT	152
	153	buf[n++] = '\n';
	154	buf[n] = '\0';
	155	return n;
	156	}
	157
8a25a2fd KS	158	#define _CPU_ATTR(name, map) \
8a25a2fd KS	159	{ __ATTR(name, 0444, show_cpus_attr, NULL), map }
9d1fe323	160
8a25a2fd	161	/* Keep in sync with cpu_subsys_attrs */
265d2e2e AK	162	static struct cpu_attr cpu_attrs[] = {
	163	_CPU_ATTR(online, &cpu_online_mask),
	164	_CPU_ATTR(possible, &cpu_possible_mask),
	165	_CPU_ATTR(present, &cpu_present_mask),
	166	};
9d1fe323	167
e057d7ae MT	168	/*
	169	* Print values for NR_CPUS and offlined cpus
	170	*/
8a25a2fd KS	171	static ssize_t print_cpus_kernel_max(struct device *dev,
8a25a2fd KS	172	struct device_attribute attr, char buf)
e057d7ae	173	{
8fd2d2d5	174	int n = snprintf(buf, PAGE_SIZE-2, "%d\n", NR_CPUS - 1);
e057d7ae MT	175	return n;
e057d7ae MT	176	}
8a25a2fd	177	static DEVICE_ATTR(kernel_max, 0444, print_cpus_kernel_max, NULL);
e057d7ae MT	178
	179	/* arch-optional setting to enable display of offline cpus >= nr_cpu_ids */
	180	unsigned int total_cpus;
	181
8a25a2fd KS	182	static ssize_t print_cpus_offline(struct device *dev,
8a25a2fd KS	183	struct device_attribute attr, char buf)
e057d7ae MT	184	{
	185	int n = 0, len = PAGE_SIZE-2;
	186	cpumask_var_t offline;
	187
	188	/* display offline cpus < nr_cpu_ids */
	189	if (!alloc_cpumask_var(&offline, GFP_KERNEL))
	190	return -ENOMEM;
cdc6e3d3	191	cpumask_andnot(offline, cpu_possible_mask, cpu_online_mask);
e057d7ae MT	192	n = cpulist_scnprintf(buf, len, offline);
	193	free_cpumask_var(offline);
	194
	195	/* display offline cpus >= nr_cpu_ids */
	196	if (total_cpus && nr_cpu_ids < total_cpus) {
	197	if (n && n < len)
	198	buf[n++] = ',';
	199
	200	if (nr_cpu_ids == total_cpus-1)
	201	n += snprintf(&buf[n], len - n, "%d", nr_cpu_ids);
	202	else
	203	n += snprintf(&buf[n], len - n, "%d-%d",
	204	nr_cpu_ids, total_cpus-1);
	205	}
	206
	207	n += snprintf(&buf[n], len - n, "\n");
	208	return n;
	209	}
8a25a2fd	210	static DEVICE_ATTR(offline, 0444, print_cpus_offline, NULL);
e057d7ae	211
2885e25c GKH	212	static void cpu_device_release(struct device *dev)
	213	{
	214	/*
	215	* This is an empty function to prevent the driver core from spitting a
	216	* warning at us. Yes, I know this is directly opposite of what the
	217	* documentation for the driver core and kobjects say, and the author
	218	* of this code has already been publically ridiculed for doing
	219	* something as foolish as this. However, at this point in time, it is
	220	* the only way to handle the issue of statically allocated cpu
	221	* devices. The different architectures will have their cpu device
	222	* code reworked to properly handle this in the near future, so this
	223	* function will then be changed to correctly free up the memory held
	224	* by the cpu device.
	225	*
	226	* Never copy this way of doing things, or you too will be made fun of
	227	* on the linux-kerenl list, you have been warned.
	228	*/
	229	}
	230
1da177e4	231	/*
405ae7d3	232	* register_cpu - Setup a sysfs device for a CPU.
72486f1f SS	233	* @cpu - cpu->hotpluggable field set to 1 will generate a control file in
72486f1f SS	234	* sysfs for this CPU.
1da177e4 LT	235	* @num - CPU number to use when creating the device.
	236	*
	237	* Initialize and register the CPU device.
	238	*/
33b5f31b	239	int __cpuinit register_cpu(struct cpu *cpu, int num)
1da177e4 LT	240	{
1da177e4 LT	241	int error;
76b67ed9	242
8a25a2fd	243	cpu->node_id = cpu_to_node(num);
29bb5d4f	244	memset(&cpu->dev, 0x00, sizeof(struct device));
8a25a2fd KS	245	cpu->dev.id = num;
8a25a2fd KS	246	cpu->dev.bus = &cpu_subsys;
2885e25c	247	cpu->dev.release = cpu_device_release;
fad12ac8 TR	248	#ifdef CONFIG_ARCH_HAS_CPU_AUTOPROBE
	249	cpu->dev.bus->uevent = arch_cpu_uevent;
	250	#endif
8a25a2fd	251	error = device_register(&cpu->dev);
72486f1f	252	if (!error && cpu->hotpluggable)
1da177e4	253	register_cpu_control(cpu);
ad74557a	254	if (!error)
8a25a2fd	255	per_cpu(cpu_sys_devices, num) = &cpu->dev;
76b67ed9 KH	256	if (!error)
76b67ed9 KH	257	register_cpu_under_node(num, cpu_to_node(num));
51be5606 VG	258
	259	#ifdef CONFIG_KEXEC
	260	if (!error)
8a25a2fd	261	error = device_create_file(&cpu->dev, &dev_attr_crash_notes);
51be5606	262	#endif
1da177e4 LT	263	return error;
	264	}
	265
8a25a2fd	266	struct device *get_cpu_device(unsigned cpu)
ad74557a	267	{
e37d05da MT	268	if (cpu < nr_cpu_ids && cpu_possible(cpu))
e37d05da MT	269	return per_cpu(cpu_sys_devices, cpu);
ad74557a AR	270	else
	271	return NULL;
	272	}
8a25a2fd KS	273	EXPORT_SYMBOL_GPL(get_cpu_device);
8a25a2fd KS	274
fad12ac8 TR	275	#ifdef CONFIG_ARCH_HAS_CPU_AUTOPROBE
	276	static DEVICE_ATTR(modalias, 0444, arch_print_cpu_modalias, NULL);
	277	#endif
	278
8a25a2fd KS	279	static struct attribute *cpu_root_attrs[] = {
	280	#ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
	281	&dev_attr_probe.attr,
	282	&dev_attr_release.attr,
	283	#endif
	284	&cpu_attrs[0].attr.attr,
	285	&cpu_attrs[1].attr.attr,
	286	&cpu_attrs[2].attr.attr,
	287	&dev_attr_kernel_max.attr,
	288	&dev_attr_offline.attr,
fad12ac8 TR	289	#ifdef CONFIG_ARCH_HAS_CPU_AUTOPROBE
	290	&dev_attr_modalias.attr,
	291	#endif
8a25a2fd KS	292	NULL
	293	};
	294
	295	static struct attribute_group cpu_root_attr_group = {
	296	.attrs = cpu_root_attrs,
	297	};
	298
	299	static const struct attribute_group *cpu_root_attr_groups[] = {
	300	&cpu_root_attr_group,
	301	NULL,
	302	};
1da177e4	303
2987557f JT	304	bool cpu_is_hotpluggable(unsigned cpu)
2987557f JT	305	{
7affca35 LT	306	struct device *dev = get_cpu_device(cpu);
7affca35 LT	307	return dev && container_of(dev, struct cpu, dev)->hotpluggable;
2987557f JT	308	}
	309	EXPORT_SYMBOL_GPL(cpu_is_hotpluggable);
	310
9f13a1fd BH	311	#ifdef CONFIG_GENERIC_CPU_DEVICES
	312	static DEFINE_PER_CPU(struct cpu, cpu_devices);
	313	#endif
	314
	315	static void __init cpu_dev_register_generic(void)
	316	{
	317	#ifdef CONFIG_GENERIC_CPU_DEVICES
	318	int i;
	319
	320	for_each_possible_cpu(i) {
	321	if (register_cpu(&per_cpu(cpu_devices, i), i))
	322	panic("Failed to register CPU device");
	323	}
	324	#endif
	325	}
	326
024f7846	327	void __init cpu_dev_init(void)
1da177e4	328	{
024f7846 BH	329	if (subsys_system_register(&cpu_subsys, cpu_root_attr_groups))
024f7846 BH	330	panic("Failed to register CPU subsystem");
8a25a2fd	331
9f13a1fd	332	cpu_dev_register_generic();
1da177e4	333	}