[linux-2.6-block.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 <linux/acpi.h>
#include <linux/of.h>
#include <linux/cpufeature.h>
#include <linux/tick.h>

#include "base.h"

static DEFINE_PER_CPU(struct device *, cpu_sys_devices);

static int cpu_subsys_match(struct device *dev, struct device_driver *drv)
{
	/* ACPI style match is the only one that may succeed. */
	if (acpi_driver_match_device(dev, drv))
		return 1;

	return 0;
}

#ifdef CONFIG_HOTPLUG_CPU
static void change_cpu_under_node(struct cpu *cpu,
			unsigned int from_nid, unsigned int to_nid)
{
	int cpuid = cpu->dev.id;
	unregister_cpu_under_node(cpuid, from_nid);
	register_cpu_under_node(cpuid, to_nid);
	cpu->node_id = to_nid;
}

static int cpu_subsys_online(struct device *dev)
{
	struct cpu *cpu = container_of(dev, struct cpu, dev);
	int cpuid = dev->id;
	int from_nid, to_nid;
	int ret;

	from_nid = cpu_to_node(cpuid);
	if (from_nid == NUMA_NO_NODE)
		return -ENODEV;

	ret = cpu_up(cpuid);
	/*
	 * When hot adding memory to memoryless node and enabling a cpu
	 * on the node, node number of the cpu may internally change.
	 */
	to_nid = cpu_to_node(cpuid);
	if (from_nid != to_nid)
		change_cpu_under_node(cpu, from_nid, to_nid);

	return ret;
}

static int cpu_subsys_offline(struct device *dev)
{
	return cpu_down(dev->id);
}

void unregister_cpu(struct cpu *cpu)
{
	int logical_cpu = cpu->dev.id;

	unregister_cpu_under_node(logical_cpu, cpu_to_node(logical_cpu));

	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)
{
	ssize_t cnt;
	int ret;

	ret = lock_device_hotplug_sysfs();
	if (ret)
		return ret;

	cnt = arch_cpu_probe(buf, count);

	unlock_device_hotplug();
	return cnt;
}

static ssize_t cpu_release_store(struct device *dev,
				 struct device_attribute *attr,
				 const char *buf,
				 size_t count)
{
	ssize_t cnt;
	int ret;

	ret = lock_device_hotplug_sysfs();
	if (ret)
		return ret;

	cnt = arch_cpu_release(buf, count);

	unlock_device_hotplug();
	return cnt;
}

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 */
#endif /* CONFIG_HOTPLUG_CPU */

struct bus_type cpu_subsys = {
	.name = "cpu",
	.dev_name = "cpu",
	.match = cpu_subsys_match,
#ifdef CONFIG_HOTPLUG_CPU
	.online = cpu_subsys_online,
	.offline = cpu_subsys_offline,
#endif
};
EXPORT_SYMBOL_GPL(cpu_subsys);

#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);

static ssize_t show_crash_notes_size(struct device *dev,
				     struct device_attribute *attr,
				     char *buf)
{
	ssize_t rc;

	rc = sprintf(buf, "%zu\n", sizeof(note_buf_t));
	return rc;
}
static DEVICE_ATTR(crash_notes_size, 0400, show_crash_notes_size, NULL);

static struct attribute *crash_note_cpu_attrs[] = {
	&dev_attr_crash_notes.attr,
	&dev_attr_crash_notes_size.attr,
	NULL
};

static struct attribute_group crash_note_cpu_attr_group = {
	.attrs = crash_note_cpu_attrs,
};
#endif

static const struct attribute_group *common_cpu_attr_groups[] = {
#ifdef CONFIG_KEXEC
	&crash_note_cpu_attr_group,
#endif
	NULL
};

static const struct attribute_group *hotplugable_cpu_attr_groups[] = {
#ifdef CONFIG_KEXEC
	&crash_note_cpu_attr_group,
#endif
	NULL
};

/*
 * 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);

	return cpumap_print_to_pagebuf(true, buf, *ca->map);
}

#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 = scnprintf(buf, len, "%*pbl", cpumask_pr_args(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 ssize_t print_cpus_isolated(struct device *dev,
				  struct device_attribute *attr, char *buf)
{
	int n = 0, len = PAGE_SIZE-2;

	n = scnprintf(buf, len, "%*pbl\n", cpumask_pr_args(cpu_isolated_map));

	return n;
}
static DEVICE_ATTR(isolated, 0444, print_cpus_isolated, NULL);

#ifdef CONFIG_NO_HZ_FULL
static ssize_t print_cpus_nohz_full(struct device *dev,
				  struct device_attribute *attr, char *buf)
{
	int n = 0, len = PAGE_SIZE-2;

	n = scnprintf(buf, len, "%*pbl\n", cpumask_pr_args(tick_nohz_full_mask));

	return n;
}
static DEVICE_ATTR(nohz_full, 0444, print_cpus_nohz_full, NULL);
#endif

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-kernel list, you have been warned.
	 */
}

#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
static ssize_t print_cpu_modalias(struct device *dev,
				  struct device_attribute *attr,
				  char *buf)
{
	ssize_t n;
	u32 i;

	n = sprintf(buf, "cpu:type:" CPU_FEATURE_TYPEFMT ":feature:",
		    CPU_FEATURE_TYPEVAL);

	for (i = 0; i < MAX_CPU_FEATURES; i++)
		if (cpu_have_feature(i)) {
			if (PAGE_SIZE < n + sizeof(",XXXX\n")) {
				WARN(1, "CPU features overflow page\n");
				break;
			}
			n += sprintf(&buf[n], ",%04X", i);
		}
	buf[n++] = '\n';
	return n;
}

static int cpu_uevent(struct device *dev, struct kobj_uevent_env *env)
{
	char *buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
	if (buf) {
		print_cpu_modalias(NULL, NULL, buf);
		add_uevent_var(env, "MODALIAS=%s", buf);
		kfree(buf);
	}
	return 0;
}
#endif

/*
 * 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 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;
	cpu->dev.offline_disabled = !cpu->hotpluggable;
	cpu->dev.offline = !cpu_online(num);
	cpu->dev.of_node = of_get_cpu_node(num, NULL);
#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
	cpu->dev.bus->uevent = cpu_uevent;
#endif
	cpu->dev.groups = common_cpu_attr_groups;
	if (cpu->hotpluggable)
		cpu->dev.groups = hotplugable_cpu_attr_groups;
	error = device_register(&cpu->dev);
	if (!error)
		per_cpu(cpu_sys_devices, num) = &cpu->dev;
	if (!error)
		register_cpu_under_node(num, cpu_to_node(num));

	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);

static void device_create_release(struct device *dev)
{
	kfree(dev);
}

static struct device *
__cpu_device_create(struct device *parent, void *drvdata,
		    const struct attribute_group **groups,
		    const char *fmt, va_list args)
{
	struct device *dev = NULL;
	int retval = -ENODEV;

	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
	if (!dev) {
		retval = -ENOMEM;
		goto error;
	}

	device_initialize(dev);
	dev->parent = parent;
	dev->groups = groups;
	dev->release = device_create_release;
	dev_set_drvdata(dev, drvdata);

	retval = kobject_set_name_vargs(&dev->kobj, fmt, args);
	if (retval)
		goto error;

	retval = device_add(dev);
	if (retval)
		goto error;

	return dev;

error:
	put_device(dev);
	return ERR_PTR(retval);
}

struct device *cpu_device_create(struct device *parent, void *drvdata,
				 const struct attribute_group **groups,
				 const char *fmt, ...)
{
	va_list vargs;
	struct device *dev;

	va_start(vargs, fmt);
	dev = __cpu_device_create(parent, drvdata, groups, fmt, vargs);
	va_end(vargs);
	return dev;
}
EXPORT_SYMBOL_GPL(cpu_device_create);

#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
static DEVICE_ATTR(modalias, 0444, 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,
	&dev_attr_isolated.attr,
#ifdef CONFIG_NO_HZ_FULL
	&dev_attr_nohz_full.attr,
#endif
#ifdef CONFIG_GENERIC_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
	1	/*
	2	* CPU subsystem support
	3	*/
	4
	5	#include <linux/kernel.h>
	6	#include <linux/module.h>
	7	#include <linux/init.h>
	8	#include <linux/sched.h>
	9	#include <linux/cpu.h>
	10	#include <linux/topology.h>
	11	#include <linux/device.h>
	12	#include <linux/node.h>
	13	#include <linux/gfp.h>
	14	#include <linux/slab.h>
	15	#include <linux/percpu.h>
	16	#include <linux/acpi.h>
	17	#include <linux/of.h>
	18	#include <linux/cpufeature.h>
	19	#include <linux/tick.h>
	20
	21	#include "base.h"
	22
	23	static DEFINE_PER_CPU(struct device *, cpu_sys_devices);
	24
	25	static int cpu_subsys_match(struct device dev, struct device_driver drv)
	26	{
	27	/* ACPI style match is the only one that may succeed. */
	28	if (acpi_driver_match_device(dev, drv))
	29	return 1;
	30
	31	return 0;
	32	}
	33
	34	#ifdef CONFIG_HOTPLUG_CPU
	35	static void change_cpu_under_node(struct cpu *cpu,
	36	unsigned int from_nid, unsigned int to_nid)
	37	{
	38	int cpuid = cpu->dev.id;
	39	unregister_cpu_under_node(cpuid, from_nid);
	40	register_cpu_under_node(cpuid, to_nid);
	41	cpu->node_id = to_nid;
	42	}
	43
	44	static int cpu_subsys_online(struct device *dev)
	45	{
	46	struct cpu *cpu = container_of(dev, struct cpu, dev);
	47	int cpuid = dev->id;
	48	int from_nid, to_nid;
	49	int ret;
	50
	51	from_nid = cpu_to_node(cpuid);
	52	if (from_nid == NUMA_NO_NODE)
	53	return -ENODEV;
	54
	55	ret = cpu_up(cpuid);
	56	/*
	57	* When hot adding memory to memoryless node and enabling a cpu
	58	* on the node, node number of the cpu may internally change.
	59	*/
	60	to_nid = cpu_to_node(cpuid);
	61	if (from_nid != to_nid)
	62	change_cpu_under_node(cpu, from_nid, to_nid);
	63
	64	return ret;
	65	}
	66
	67	static int cpu_subsys_offline(struct device *dev)
	68	{
	69	return cpu_down(dev->id);
	70	}
	71
	72	void unregister_cpu(struct cpu *cpu)
	73	{
	74	int logical_cpu = cpu->dev.id;
	75
	76	unregister_cpu_under_node(logical_cpu, cpu_to_node(logical_cpu));
	77
	78	device_unregister(&cpu->dev);
	79	per_cpu(cpu_sys_devices, logical_cpu) = NULL;
	80	return;
	81	}
	82
	83	#ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
	84	static ssize_t cpu_probe_store(struct device *dev,
	85	struct device_attribute *attr,
	86	const char *buf,
	87	size_t count)
	88	{
	89	ssize_t cnt;
	90	int ret;
	91
	92	ret = lock_device_hotplug_sysfs();
	93	if (ret)
	94	return ret;
	95
	96	cnt = arch_cpu_probe(buf, count);
	97
	98	unlock_device_hotplug();
	99	return cnt;
	100	}
	101
	102	static ssize_t cpu_release_store(struct device *dev,
	103	struct device_attribute *attr,
	104	const char *buf,
	105	size_t count)
	106	{
	107	ssize_t cnt;
	108	int ret;
	109
	110	ret = lock_device_hotplug_sysfs();
	111	if (ret)
	112	return ret;
	113
	114	cnt = arch_cpu_release(buf, count);
	115
	116	unlock_device_hotplug();
	117	return cnt;
	118	}
	119
	120	static DEVICE_ATTR(probe, S_IWUSR, NULL, cpu_probe_store);
	121	static DEVICE_ATTR(release, S_IWUSR, NULL, cpu_release_store);
	122	#endif /* CONFIG_ARCH_CPU_PROBE_RELEASE */
	123	#endif /* CONFIG_HOTPLUG_CPU */
	124
	125	struct bus_type cpu_subsys = {
	126	.name = "cpu",
	127	.dev_name = "cpu",
	128	.match = cpu_subsys_match,
	129	#ifdef CONFIG_HOTPLUG_CPU
	130	.online = cpu_subsys_online,
	131	.offline = cpu_subsys_offline,
	132	#endif
	133	};
	134	EXPORT_SYMBOL_GPL(cpu_subsys);
	135
	136	#ifdef CONFIG_KEXEC
	137	#include <linux/kexec.h>
	138
	139	static ssize_t show_crash_notes(struct device dev, struct device_attribute attr,
	140	char *buf)
	141	{
	142	struct cpu *cpu = container_of(dev, struct cpu, dev);
	143	ssize_t rc;
	144	unsigned long long addr;
	145	int cpunum;
	146
	147	cpunum = cpu->dev.id;
	148
	149	/*
	150	* Might be reading other cpu's data based on which cpu read thread
	151	* has been scheduled. But cpu data (memory) is allocated once during
	152	* boot up and this data does not change there after. Hence this
	153	* operation should be safe. No locking required.
	154	*/
	155	addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpunum));
	156	rc = sprintf(buf, "%Lx\n", addr);
	157	return rc;
	158	}
	159	static DEVICE_ATTR(crash_notes, 0400, show_crash_notes, NULL);
	160
	161	static ssize_t show_crash_notes_size(struct device *dev,
	162	struct device_attribute *attr,
	163	char *buf)
	164	{
	165	ssize_t rc;
	166
	167	rc = sprintf(buf, "%zu\n", sizeof(note_buf_t));
	168	return rc;
	169	}
	170	static DEVICE_ATTR(crash_notes_size, 0400, show_crash_notes_size, NULL);
	171
	172	static struct attribute *crash_note_cpu_attrs[] = {
	173	&dev_attr_crash_notes.attr,
	174	&dev_attr_crash_notes_size.attr,
	175	NULL
	176	};
	177
	178	static struct attribute_group crash_note_cpu_attr_group = {
	179	.attrs = crash_note_cpu_attrs,
	180	};
	181	#endif
	182
	183	static const struct attribute_group *common_cpu_attr_groups[] = {
	184	#ifdef CONFIG_KEXEC
	185	&crash_note_cpu_attr_group,
	186	#endif
	187	NULL
	188	};
	189
	190	static const struct attribute_group *hotplugable_cpu_attr_groups[] = {
	191	#ifdef CONFIG_KEXEC
	192	&crash_note_cpu_attr_group,
	193	#endif
	194	NULL
	195	};
	196
	197	/*
	198	* Print cpu online, possible, present, and system maps
	199	*/
	200
	201	struct cpu_attr {
	202	struct device_attribute attr;
	203	const struct cpumask const const map;
	204	};
	205
	206	static ssize_t show_cpus_attr(struct device *dev,
	207	struct device_attribute *attr,
	208	char *buf)
	209	{
	210	struct cpu_attr *ca = container_of(attr, struct cpu_attr, attr);
	211
	212	return cpumap_print_to_pagebuf(true, buf, *ca->map);
	213	}
	214
	215	#define _CPU_ATTR(name, map) \
	216	{ __ATTR(name, 0444, show_cpus_attr, NULL), map }
	217
	218	/* Keep in sync with cpu_subsys_attrs */
	219	static struct cpu_attr cpu_attrs[] = {
	220	_CPU_ATTR(online, &cpu_online_mask),
	221	_CPU_ATTR(possible, &cpu_possible_mask),
	222	_CPU_ATTR(present, &cpu_present_mask),
	223	};
	224
	225	/*
	226	* Print values for NR_CPUS and offlined cpus
	227	*/
	228	static ssize_t print_cpus_kernel_max(struct device *dev,
	229	struct device_attribute attr, char buf)
	230	{
	231	int n = snprintf(buf, PAGE_SIZE-2, "%d\n", NR_CPUS - 1);
	232	return n;
	233	}
	234	static DEVICE_ATTR(kernel_max, 0444, print_cpus_kernel_max, NULL);
	235
	236	/* arch-optional setting to enable display of offline cpus >= nr_cpu_ids */
	237	unsigned int total_cpus;
	238
	239	static ssize_t print_cpus_offline(struct device *dev,
	240	struct device_attribute attr, char buf)
	241	{
	242	int n = 0, len = PAGE_SIZE-2;
	243	cpumask_var_t offline;
	244
	245	/* display offline cpus < nr_cpu_ids */
	246	if (!alloc_cpumask_var(&offline, GFP_KERNEL))
	247	return -ENOMEM;
	248	cpumask_andnot(offline, cpu_possible_mask, cpu_online_mask);
	249	n = scnprintf(buf, len, "%*pbl", cpumask_pr_args(offline));
	250	free_cpumask_var(offline);
	251
	252	/* display offline cpus >= nr_cpu_ids */
	253	if (total_cpus && nr_cpu_ids < total_cpus) {
	254	if (n && n < len)
	255	buf[n++] = ',';
	256
	257	if (nr_cpu_ids == total_cpus-1)
	258	n += snprintf(&buf[n], len - n, "%d", nr_cpu_ids);
	259	else
	260	n += snprintf(&buf[n], len - n, "%d-%d",
	261	nr_cpu_ids, total_cpus-1);
	262	}
	263
	264	n += snprintf(&buf[n], len - n, "\n");
	265	return n;
	266	}
	267	static DEVICE_ATTR(offline, 0444, print_cpus_offline, NULL);
	268
	269	static ssize_t print_cpus_isolated(struct device *dev,
	270	struct device_attribute attr, char buf)
	271	{
	272	int n = 0, len = PAGE_SIZE-2;
	273
	274	n = scnprintf(buf, len, "%*pbl\n", cpumask_pr_args(cpu_isolated_map));
	275
	276	return n;
	277	}
	278	static DEVICE_ATTR(isolated, 0444, print_cpus_isolated, NULL);
	279
	280	#ifdef CONFIG_NO_HZ_FULL
	281	static ssize_t print_cpus_nohz_full(struct device *dev,
	282	struct device_attribute attr, char buf)
	283	{
	284	int n = 0, len = PAGE_SIZE-2;
	285
	286	n = scnprintf(buf, len, "%*pbl\n", cpumask_pr_args(tick_nohz_full_mask));
	287
	288	return n;
	289	}
	290	static DEVICE_ATTR(nohz_full, 0444, print_cpus_nohz_full, NULL);
	291	#endif
	292
	293	static void cpu_device_release(struct device *dev)
	294	{
	295	/*
	296	* This is an empty function to prevent the driver core from spitting a
	297	* warning at us. Yes, I know this is directly opposite of what the
	298	* documentation for the driver core and kobjects say, and the author
	299	* of this code has already been publically ridiculed for doing
	300	* something as foolish as this. However, at this point in time, it is
	301	* the only way to handle the issue of statically allocated cpu
	302	* devices. The different architectures will have their cpu device
	303	* code reworked to properly handle this in the near future, so this
	304	* function will then be changed to correctly free up the memory held
	305	* by the cpu device.
	306	*
	307	* Never copy this way of doing things, or you too will be made fun of
	308	* on the linux-kernel list, you have been warned.
	309	*/
	310	}
	311
	312	#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
	313	static ssize_t print_cpu_modalias(struct device *dev,
	314	struct device_attribute *attr,
	315	char *buf)
	316	{
	317	ssize_t n;
	318	u32 i;
	319
	320	n = sprintf(buf, "cpu:type:" CPU_FEATURE_TYPEFMT ":feature:",
	321	CPU_FEATURE_TYPEVAL);
	322
	323	for (i = 0; i < MAX_CPU_FEATURES; i++)
	324	if (cpu_have_feature(i)) {
	325	if (PAGE_SIZE < n + sizeof(",XXXX\n")) {
	326	WARN(1, "CPU features overflow page\n");
	327	break;
	328	}
	329	n += sprintf(&buf[n], ",%04X", i);
	330	}
	331	buf[n++] = '\n';
	332	return n;
	333	}
	334
	335	static int cpu_uevent(struct device dev, struct kobj_uevent_env env)
	336	{
	337	char *buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
	338	if (buf) {
	339	print_cpu_modalias(NULL, NULL, buf);
	340	add_uevent_var(env, "MODALIAS=%s", buf);
	341	kfree(buf);
	342	}
	343	return 0;
	344	}
	345	#endif
	346
	347	/*
	348	* register_cpu - Setup a sysfs device for a CPU.
	349	* @cpu - cpu->hotpluggable field set to 1 will generate a control file in
	350	* sysfs for this CPU.
	351	* @num - CPU number to use when creating the device.
	352	*
	353	* Initialize and register the CPU device.
	354	*/
	355	int register_cpu(struct cpu *cpu, int num)
	356	{
	357	int error;
	358
	359	cpu->node_id = cpu_to_node(num);
	360	memset(&cpu->dev, 0x00, sizeof(struct device));
	361	cpu->dev.id = num;
	362	cpu->dev.bus = &cpu_subsys;
	363	cpu->dev.release = cpu_device_release;
	364	cpu->dev.offline_disabled = !cpu->hotpluggable;
	365	cpu->dev.offline = !cpu_online(num);
	366	cpu->dev.of_node = of_get_cpu_node(num, NULL);
	367	#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
	368	cpu->dev.bus->uevent = cpu_uevent;
	369	#endif
	370	cpu->dev.groups = common_cpu_attr_groups;
	371	if (cpu->hotpluggable)
	372	cpu->dev.groups = hotplugable_cpu_attr_groups;
	373	error = device_register(&cpu->dev);
	374	if (!error)
	375	per_cpu(cpu_sys_devices, num) = &cpu->dev;
	376	if (!error)
	377	register_cpu_under_node(num, cpu_to_node(num));
	378
	379	return error;
	380	}
	381
	382	struct device *get_cpu_device(unsigned cpu)
	383	{
	384	if (cpu < nr_cpu_ids && cpu_possible(cpu))
	385	return per_cpu(cpu_sys_devices, cpu);
	386	else
	387	return NULL;
	388	}
	389	EXPORT_SYMBOL_GPL(get_cpu_device);
	390
	391	static void device_create_release(struct device *dev)
	392	{
	393	kfree(dev);
	394	}
	395
	396	static struct device *
	397	__cpu_device_create(struct device parent, void drvdata,
	398	const struct attribute_group **groups,
	399	const char *fmt, va_list args)
	400	{
	401	struct device *dev = NULL;
	402	int retval = -ENODEV;
	403
	404	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
	405	if (!dev) {
	406	retval = -ENOMEM;
	407	goto error;
	408	}
	409
	410	device_initialize(dev);
	411	dev->parent = parent;
	412	dev->groups = groups;
	413	dev->release = device_create_release;
	414	dev_set_drvdata(dev, drvdata);
	415
	416	retval = kobject_set_name_vargs(&dev->kobj, fmt, args);
	417	if (retval)
	418	goto error;
	419
	420	retval = device_add(dev);
	421	if (retval)
	422	goto error;
	423
	424	return dev;
	425
	426	error:
	427	put_device(dev);
	428	return ERR_PTR(retval);
	429	}
	430
	431	struct device cpu_device_create(struct device parent, void *drvdata,
	432	const struct attribute_group **groups,
	433	const char *fmt, ...)
	434	{
	435	va_list vargs;
	436	struct device *dev;
	437
	438	va_start(vargs, fmt);
	439	dev = __cpu_device_create(parent, drvdata, groups, fmt, vargs);
	440	va_end(vargs);
	441	return dev;
	442	}
	443	EXPORT_SYMBOL_GPL(cpu_device_create);
	444
	445	#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
	446	static DEVICE_ATTR(modalias, 0444, print_cpu_modalias, NULL);
	447	#endif
	448
	449	static struct attribute *cpu_root_attrs[] = {
	450	#ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
	451	&dev_attr_probe.attr,
	452	&dev_attr_release.attr,
	453	#endif
	454	&cpu_attrs[0].attr.attr,
	455	&cpu_attrs[1].attr.attr,
	456	&cpu_attrs[2].attr.attr,
	457	&dev_attr_kernel_max.attr,
	458	&dev_attr_offline.attr,
	459	&dev_attr_isolated.attr,
	460	#ifdef CONFIG_NO_HZ_FULL
	461	&dev_attr_nohz_full.attr,
	462	#endif
	463	#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
	464	&dev_attr_modalias.attr,
	465	#endif
	466	NULL
	467	};
	468
	469	static struct attribute_group cpu_root_attr_group = {
	470	.attrs = cpu_root_attrs,
	471	};
	472
	473	static const struct attribute_group *cpu_root_attr_groups[] = {
	474	&cpu_root_attr_group,
	475	NULL,
	476	};
	477
	478	bool cpu_is_hotpluggable(unsigned cpu)
	479	{
	480	struct device *dev = get_cpu_device(cpu);
	481	return dev && container_of(dev, struct cpu, dev)->hotpluggable;
	482	}
	483	EXPORT_SYMBOL_GPL(cpu_is_hotpluggable);
	484
	485	#ifdef CONFIG_GENERIC_CPU_DEVICES
	486	static DEFINE_PER_CPU(struct cpu, cpu_devices);
	487	#endif
	488
	489	static void __init cpu_dev_register_generic(void)
	490	{
	491	#ifdef CONFIG_GENERIC_CPU_DEVICES
	492	int i;
	493
	494	for_each_possible_cpu(i) {
	495	if (register_cpu(&per_cpu(cpu_devices, i), i))
	496	panic("Failed to register CPU device");
	497	}
	498	#endif
	499	}
	500
	501	void __init cpu_dev_init(void)
	502	{
	503	if (subsys_system_register(&cpu_subsys, cpu_root_attr_groups))
	504	panic("Failed to register CPU subsystem");
	505
	506	cpu_dev_register_generic();
	507	}