[mirror_ubuntu-zesty-kernel.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 "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 __ref 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);
	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-kernel list, you have been warned.
	 */
}

#ifdef CONFIG_HAVE_CPU_AUTOPROBE
#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;
}
#else
#define print_cpu_modalias	arch_print_cpu_modalias
#endif

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_HAVE_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);

#ifdef CONFIG_HAVE_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,
#ifdef CONFIG_HAVE_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>
ac212b69	16	#include <linux/acpi.h>
f86e4718	17	#include <linux/of.h>
67bad2fd	18	#include <linux/cpufeature.h>
1da177e4	19
a1bdc7aa	20	#include "base.h"
1da177e4	21
8a25a2fd	22	static DEFINE_PER_CPU(struct device *, cpu_sys_devices);
ad74557a	23
ac212b69 RW	24	static int cpu_subsys_match(struct device dev, struct device_driver drv)
	25	{
	26	/* ACPI style match is the only one that may succeed. */
	27	if (acpi_driver_match_device(dev, drv))
	28	return 1;
	29
	30	return 0;
	31	}
	32
1da177e4	33	#ifdef CONFIG_HOTPLUG_CPU
34640468 YI	34	static void change_cpu_under_node(struct cpu *cpu,
	35	unsigned int from_nid, unsigned int to_nid)
	36	{
	37	int cpuid = cpu->dev.id;
	38	unregister_cpu_under_node(cpuid, from_nid);
	39	register_cpu_under_node(cpuid, to_nid);
	40	cpu->node_id = to_nid;
	41	}
	42
0902a904	43	static int __ref cpu_subsys_online(struct device *dev)
1da177e4	44	{
8a25a2fd	45	struct cpu *cpu = container_of(dev, struct cpu, dev);
0902a904 RW	46	int cpuid = dev->id;
0902a904 RW	47	int from_nid, to_nid;
6dedcca6	48	int ret;
1da177e4	49
0902a904	50	from_nid = cpu_to_node(cpuid);
c7991b0b	51	if (from_nid == NUMA_NO_NODE)
6dedcca6	52	return -ENODEV;
c7991b0b	53
0902a904 RW	54	ret = cpu_up(cpuid);
	55	/*
	56	* When hot adding memory to memoryless node and enabling a cpu
	57	* on the node, node number of the cpu may internally change.
	58	*/
	59	to_nid = cpu_to_node(cpuid);
	60	if (from_nid != to_nid)
	61	change_cpu_under_node(cpu, from_nid, to_nid);
1da177e4	62
0902a904	63	return ret;
1da177e4 LT	64	}
1da177e4 LT	65
0902a904	66	static int cpu_subsys_offline(struct device *dev)
1da177e4	67	{
6dedcca6	68	return cpu_down(dev->id);
1da177e4	69	}
1c4e2d70	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_unregister(&cpu->dev);
e37d05da	78	per_cpu(cpu_sys_devices, logical_cpu) = NULL;
1da177e4 LT	79	return;
1da177e4 LT	80	}
12633e80 NF	81
12633e80 NF	82	#ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
8a25a2fd KS	83	static ssize_t cpu_probe_store(struct device *dev,
8a25a2fd KS	84	struct device_attribute *attr,
67fc233f	85	const char *buf,
12633e80 NF	86	size_t count)
12633e80 NF	87	{
574b851e TK	88	ssize_t cnt;
	89	int ret;
	90
	91	ret = lock_device_hotplug_sysfs();
	92	if (ret)
	93	return ret;
	94
	95	cnt = arch_cpu_probe(buf, count);
	96
	97	unlock_device_hotplug();
	98	return cnt;
12633e80 NF	99	}
12633e80 NF	100
8a25a2fd KS	101	static ssize_t cpu_release_store(struct device *dev,
8a25a2fd KS	102	struct device_attribute *attr,
67fc233f	103	const char *buf,
12633e80 NF	104	size_t count)
12633e80 NF	105	{
574b851e TK	106	ssize_t cnt;
	107	int ret;
	108
	109	ret = lock_device_hotplug_sysfs();
	110	if (ret)
	111	return ret;
	112
	113	cnt = arch_cpu_release(buf, count);
	114
	115	unlock_device_hotplug();
	116	return cnt;
12633e80 NF	117	}
12633e80 NF	118
8a25a2fd KS	119	static DEVICE_ATTR(probe, S_IWUSR, NULL, cpu_probe_store);
8a25a2fd KS	120	static DEVICE_ATTR(release, S_IWUSR, NULL, cpu_release_store);
12633e80	121	#endif /* CONFIG_ARCH_CPU_PROBE_RELEASE */
1da177e4 LT	122	#endif /* CONFIG_HOTPLUG_CPU */
1da177e4 LT	123
0902a904 RW	124	struct bus_type cpu_subsys = {
	125	.name = "cpu",
	126	.dev_name = "cpu",
ac212b69	127	.match = cpu_subsys_match,
0902a904 RW	128	#ifdef CONFIG_HOTPLUG_CPU
	129	.online = cpu_subsys_online,
	130	.offline = cpu_subsys_offline,
	131	#endif
	132	};
	133	EXPORT_SYMBOL_GPL(cpu_subsys);
	134
51be5606 VG	135	#ifdef CONFIG_KEXEC
	136	#include <linux/kexec.h>
	137
8a25a2fd	138	static ssize_t show_crash_notes(struct device dev, struct device_attribute attr,
4a0b2b4d	139	char *buf)
51be5606	140	{
8a25a2fd	141	struct cpu *cpu = container_of(dev, struct cpu, dev);
51be5606 VG	142	ssize_t rc;
	143	unsigned long long addr;
	144	int cpunum;
	145
8a25a2fd	146	cpunum = cpu->dev.id;
51be5606 VG	147
	148	/*
	149	* Might be reading other cpu's data based on which cpu read thread
	150	* has been scheduled. But cpu data (memory) is allocated once during
	151	* boot up and this data does not change there after. Hence this
	152	* operation should be safe. No locking required.
	153	*/
3b034b0d	154	addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpunum));
51be5606	155	rc = sprintf(buf, "%Lx\n", addr);
51be5606 VG	156	return rc;
51be5606 VG	157	}
8a25a2fd	158	static DEVICE_ATTR(crash_notes, 0400, show_crash_notes, NULL);
eca4549f ZY	159
	160	static ssize_t show_crash_notes_size(struct device *dev,
	161	struct device_attribute *attr,
	162	char *buf)
	163	{
	164	ssize_t rc;
	165
bcfb87fb	166	rc = sprintf(buf, "%zu\n", sizeof(note_buf_t));
eca4549f ZY	167	return rc;
	168	}
	169	static DEVICE_ATTR(crash_notes_size, 0400, show_crash_notes_size, NULL);
c055da9f IM	170
	171	static struct attribute *crash_note_cpu_attrs[] = {
	172	&dev_attr_crash_notes.attr,
	173	&dev_attr_crash_notes_size.attr,
	174	NULL
	175	};
	176
	177	static struct attribute_group crash_note_cpu_attr_group = {
	178	.attrs = crash_note_cpu_attrs,
	179	};
	180	#endif
	181
	182	static const struct attribute_group *common_cpu_attr_groups[] = {
	183	#ifdef CONFIG_KEXEC
	184	&crash_note_cpu_attr_group,
51be5606	185	#endif
c055da9f IM	186	NULL
c055da9f IM	187	};
51be5606	188
1c4e2d70 IM	189	static const struct attribute_group *hotplugable_cpu_attr_groups[] = {
	190	#ifdef CONFIG_KEXEC
	191	&crash_note_cpu_attr_group,
1c4e2d70 IM	192	#endif
	193	NULL
	194	};
	195
9d1fe323 MT	196	/*
	197	* Print cpu online, possible, present, and system maps
	198	*/
265d2e2e AK	199
265d2e2e AK	200	struct cpu_attr {
8a25a2fd	201	struct device_attribute attr;
265d2e2e AK	202	const struct cpumask const const map;
	203	};
	204
8a25a2fd KS	205	static ssize_t show_cpus_attr(struct device *dev,
8a25a2fd KS	206	struct device_attribute *attr,
265d2e2e	207	char *buf)
9d1fe323	208	{
265d2e2e AK	209	struct cpu_attr *ca = container_of(attr, struct cpu_attr, attr);
265d2e2e AK	210	int n = cpulist_scnprintf(buf, PAGE_SIZE-2, *(ca->map));
9d1fe323 MT	211
	212	buf[n++] = '\n';
	213	buf[n] = '\0';
	214	return n;
	215	}
	216
8a25a2fd KS	217	#define _CPU_ATTR(name, map) \
8a25a2fd KS	218	{ __ATTR(name, 0444, show_cpus_attr, NULL), map }
9d1fe323	219
8a25a2fd	220	/* Keep in sync with cpu_subsys_attrs */
265d2e2e AK	221	static struct cpu_attr cpu_attrs[] = {
	222	_CPU_ATTR(online, &cpu_online_mask),
	223	_CPU_ATTR(possible, &cpu_possible_mask),
	224	_CPU_ATTR(present, &cpu_present_mask),
	225	};
9d1fe323	226
e057d7ae MT	227	/*
	228	* Print values for NR_CPUS and offlined cpus
	229	*/
8a25a2fd KS	230	static ssize_t print_cpus_kernel_max(struct device *dev,
8a25a2fd KS	231	struct device_attribute attr, char buf)
e057d7ae	232	{
8fd2d2d5	233	int n = snprintf(buf, PAGE_SIZE-2, "%d\n", NR_CPUS - 1);
e057d7ae MT	234	return n;
e057d7ae MT	235	}
8a25a2fd	236	static DEVICE_ATTR(kernel_max, 0444, print_cpus_kernel_max, NULL);
e057d7ae MT	237
	238	/* arch-optional setting to enable display of offline cpus >= nr_cpu_ids */
	239	unsigned int total_cpus;
	240
8a25a2fd KS	241	static ssize_t print_cpus_offline(struct device *dev,
8a25a2fd KS	242	struct device_attribute attr, char buf)
e057d7ae MT	243	{
	244	int n = 0, len = PAGE_SIZE-2;
	245	cpumask_var_t offline;
	246
	247	/* display offline cpus < nr_cpu_ids */
	248	if (!alloc_cpumask_var(&offline, GFP_KERNEL))
	249	return -ENOMEM;
cdc6e3d3	250	cpumask_andnot(offline, cpu_possible_mask, cpu_online_mask);
e057d7ae MT	251	n = cpulist_scnprintf(buf, len, offline);
	252	free_cpumask_var(offline);
	253
	254	/* display offline cpus >= nr_cpu_ids */
	255	if (total_cpus && nr_cpu_ids < total_cpus) {
	256	if (n && n < len)
	257	buf[n++] = ',';
	258
	259	if (nr_cpu_ids == total_cpus-1)
	260	n += snprintf(&buf[n], len - n, "%d", nr_cpu_ids);
	261	else
	262	n += snprintf(&buf[n], len - n, "%d-%d",
	263	nr_cpu_ids, total_cpus-1);
	264	}
	265
	266	n += snprintf(&buf[n], len - n, "\n");
	267	return n;
	268	}
8a25a2fd	269	static DEVICE_ATTR(offline, 0444, print_cpus_offline, NULL);
e057d7ae	270
2885e25c GKH	271	static void cpu_device_release(struct device *dev)
	272	{
	273	/*
	274	* This is an empty function to prevent the driver core from spitting a
	275	* warning at us. Yes, I know this is directly opposite of what the
	276	* documentation for the driver core and kobjects say, and the author
	277	* of this code has already been publically ridiculed for doing
	278	* something as foolish as this. However, at this point in time, it is
	279	* the only way to handle the issue of statically allocated cpu
	280	* devices. The different architectures will have their cpu device
	281	* code reworked to properly handle this in the near future, so this
	282	* function will then be changed to correctly free up the memory held
	283	* by the cpu device.
	284	*
	285	* Never copy this way of doing things, or you too will be made fun of
30a4840a	286	* on the linux-kernel list, you have been warned.
2885e25c GKH	287	*/
	288	}
	289
67bad2fd AB	290	#ifdef CONFIG_HAVE_CPU_AUTOPROBE
	291	#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
	292	static ssize_t print_cpu_modalias(struct device *dev,
	293	struct device_attribute *attr,
	294	char *buf)
	295	{
	296	ssize_t n;
	297	u32 i;
	298
	299	n = sprintf(buf, "cpu:type:" CPU_FEATURE_TYPEFMT ":feature:",
	300	CPU_FEATURE_TYPEVAL);
	301
	302	for (i = 0; i < MAX_CPU_FEATURES; i++)
	303	if (cpu_have_feature(i)) {
	304	if (PAGE_SIZE < n + sizeof(",XXXX\n")) {
	305	WARN(1, "CPU features overflow page\n");
	306	break;
	307	}
	308	n += sprintf(&buf[n], ",%04X", i);
	309	}
	310	buf[n++] = '\n';
	311	return n;
	312	}
	313	#else
	314	#define print_cpu_modalias arch_print_cpu_modalias
	315	#endif
	316
	317	static int cpu_uevent(struct device dev, struct kobj_uevent_env env)
	318	{
	319	char *buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
	320	if (buf) {
	321	print_cpu_modalias(NULL, NULL, buf);
	322	add_uevent_var(env, "MODALIAS=%s", buf);
	323	kfree(buf);
	324	}
	325	return 0;
	326	}
	327	#endif
	328
1da177e4	329	/*
405ae7d3	330	* register_cpu - Setup a sysfs device for a CPU.
72486f1f SS	331	* @cpu - cpu->hotpluggable field set to 1 will generate a control file in
72486f1f SS	332	* sysfs for this CPU.
1da177e4 LT	333	* @num - CPU number to use when creating the device.
	334	*
	335	* Initialize and register the CPU device.
	336	*/
a83048eb	337	int register_cpu(struct cpu *cpu, int num)
1da177e4 LT	338	{
1da177e4 LT	339	int error;
76b67ed9	340
8a25a2fd	341	cpu->node_id = cpu_to_node(num);
29bb5d4f	342	memset(&cpu->dev, 0x00, sizeof(struct device));
8a25a2fd KS	343	cpu->dev.id = num;
8a25a2fd KS	344	cpu->dev.bus = &cpu_subsys;
2885e25c	345	cpu->dev.release = cpu_device_release;
0902a904	346	cpu->dev.offline_disabled = !cpu->hotpluggable;
1001b4d4	347	cpu->dev.offline = !cpu_online(num);
f86e4718	348	cpu->dev.of_node = of_get_cpu_node(num, NULL);
67bad2fd AB	349	#ifdef CONFIG_HAVE_CPU_AUTOPROBE
67bad2fd AB	350	cpu->dev.bus->uevent = cpu_uevent;
fad12ac8	351	#endif
c055da9f	352	cpu->dev.groups = common_cpu_attr_groups;
1c4e2d70 IM	353	if (cpu->hotpluggable)
1c4e2d70 IM	354	cpu->dev.groups = hotplugable_cpu_attr_groups;
8a25a2fd	355	error = device_register(&cpu->dev);
ad74557a	356	if (!error)
8a25a2fd	357	per_cpu(cpu_sys_devices, num) = &cpu->dev;
76b67ed9 KH	358	if (!error)
76b67ed9 KH	359	register_cpu_under_node(num, cpu_to_node(num));
51be5606	360
1da177e4 LT	361	return error;
	362	}
	363
8a25a2fd	364	struct device *get_cpu_device(unsigned cpu)
ad74557a	365	{
e37d05da MT	366	if (cpu < nr_cpu_ids && cpu_possible(cpu))
e37d05da MT	367	return per_cpu(cpu_sys_devices, cpu);
ad74557a AR	368	else
	369	return NULL;
	370	}
8a25a2fd KS	371	EXPORT_SYMBOL_GPL(get_cpu_device);
8a25a2fd KS	372
67bad2fd AB	373	#ifdef CONFIG_HAVE_CPU_AUTOPROBE
67bad2fd AB	374	static DEVICE_ATTR(modalias, 0444, print_cpu_modalias, NULL);
fad12ac8 TR	375	#endif
fad12ac8 TR	376
8a25a2fd KS	377	static struct attribute *cpu_root_attrs[] = {
	378	#ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
	379	&dev_attr_probe.attr,
	380	&dev_attr_release.attr,
	381	#endif
	382	&cpu_attrs[0].attr.attr,
	383	&cpu_attrs[1].attr.attr,
	384	&cpu_attrs[2].attr.attr,
	385	&dev_attr_kernel_max.attr,
	386	&dev_attr_offline.attr,
67bad2fd	387	#ifdef CONFIG_HAVE_CPU_AUTOPROBE
fad12ac8 TR	388	&dev_attr_modalias.attr,
fad12ac8 TR	389	#endif
8a25a2fd KS	390	NULL
	391	};
	392
	393	static struct attribute_group cpu_root_attr_group = {
	394	.attrs = cpu_root_attrs,
	395	};
	396
	397	static const struct attribute_group *cpu_root_attr_groups[] = {
	398	&cpu_root_attr_group,
	399	NULL,
	400	};
1da177e4	401
2987557f JT	402	bool cpu_is_hotpluggable(unsigned cpu)
2987557f JT	403	{
7affca35 LT	404	struct device *dev = get_cpu_device(cpu);
7affca35 LT	405	return dev && container_of(dev, struct cpu, dev)->hotpluggable;
2987557f JT	406	}
	407	EXPORT_SYMBOL_GPL(cpu_is_hotpluggable);
	408
9f13a1fd BH	409	#ifdef CONFIG_GENERIC_CPU_DEVICES
	410	static DEFINE_PER_CPU(struct cpu, cpu_devices);
	411	#endif
	412
	413	static void __init cpu_dev_register_generic(void)
	414	{
	415	#ifdef CONFIG_GENERIC_CPU_DEVICES
	416	int i;
	417
	418	for_each_possible_cpu(i) {
	419	if (register_cpu(&per_cpu(cpu_devices, i), i))
	420	panic("Failed to register CPU device");
	421	}
	422	#endif
	423	}
	424
024f7846	425	void __init cpu_dev_init(void)
1da177e4	426	{
024f7846 BH	427	if (subsys_system_register(&cpu_subsys, cpu_root_attr_groups))
024f7846 BH	428	panic("Failed to register CPU subsystem");
8a25a2fd	429
9f13a1fd	430	cpu_dev_register_generic();
1da177e4	431	}