[thirdparty/kernel/stable.git] / drivers / base / cpu.c

// SPDX-License-Identifier: GPL-2.0
/*
 * 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 <linux/pm_qos.h>
#include <linux/delay.h>
#include <linux/sched/isolation.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;
	int retries = 0;

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

retry:
	ret = cpu_device_up(dev);

	/*
	 * If -EBUSY is returned, it is likely that hotplug is temporarily
	 * disabled when cpu_hotplug_disable() was called. This condition is
	 * transient. So we retry after waiting for an exponentially
	 * increasing delay up to a total of at least 620ms as some PCI
	 * device initialization can take quite a while.
	 */
	if (ret == -EBUSY) {
		retries++;
		if (retries > 5)
			return ret;
		msleep(10 * (1 << retries));
		goto retry;
	}

	/*
	 * 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_device_down(dev);
}

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 */

#ifdef CONFIG_KEXEC_CORE
#include <linux/kexec.h>

static ssize_t crash_notes_show(struct device *dev,
				struct device_attribute *attr,
				char *buf)
{
	struct cpu *cpu = container_of(dev, struct cpu, dev);
	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));

	return sysfs_emit(buf, "%llx\n", addr);
}
static DEVICE_ATTR_ADMIN_RO(crash_notes);

static ssize_t crash_notes_size_show(struct device *dev,
				     struct device_attribute *attr,
				     char *buf)
{
	return sysfs_emit(buf, "%zu\n", sizeof(note_buf_t));
}
static DEVICE_ATTR_ADMIN_RO(crash_notes_size);

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

static const 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_CORE
	&crash_note_cpu_attr_group,
#endif
	NULL
};

static const struct attribute_group *hotplugable_cpu_attr_groups[] = {
#ifdef CONFIG_KEXEC_CORE
	&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 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)
{
	return sysfs_emit(buf, "%d\n", NR_CPUS - 1);
}
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 len = 0;
	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);
	len += sysfs_emit_at(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) {
		len += sysfs_emit_at(buf, len, ",");

		if (nr_cpu_ids == total_cpus-1)
			len += sysfs_emit_at(buf, len, "%u", nr_cpu_ids);
		else
			len += sysfs_emit_at(buf, len, "%u-%d",
					     nr_cpu_ids, total_cpus - 1);
	}

	len += sysfs_emit_at(buf, len, "\n");

	return len;
}
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 len;
	cpumask_var_t isolated;

	if (!alloc_cpumask_var(&isolated, GFP_KERNEL))
		return -ENOMEM;

	cpumask_andnot(isolated, cpu_possible_mask,
		       housekeeping_cpumask(HK_TYPE_DOMAIN));
	len = sysfs_emit(buf, "%*pbl\n", cpumask_pr_args(isolated));

	free_cpumask_var(isolated);

	return len;
}
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)
{
	return sysfs_emit(buf, "%*pbl\n", cpumask_pr_args(tick_nohz_full_mask));
}
static DEVICE_ATTR(nohz_full, 0444, print_cpus_nohz_full, NULL);
#endif

#ifdef CONFIG_CRASH_HOTPLUG
static ssize_t crash_hotplug_show(struct device *dev,
				     struct device_attribute *attr,
				     char *buf)
{
	return sysfs_emit(buf, "%d\n", crash_hotplug_cpu_support());
}
static DEVICE_ATTR_ADMIN_RO(crash_hotplug);
#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)
{
	int len = 0;
	u32 i;

	len += sysfs_emit_at(buf, len,
			     "cpu:type:" CPU_FEATURE_TYPEFMT ":feature:",
			     CPU_FEATURE_TYPEVAL);

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

static int cpu_uevent(const 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

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
#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
	.uevent = cpu_uevent,
#endif
};
EXPORT_SYMBOL_GPL(cpu_subsys);

/*
 * 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);
	cpu->dev.groups = common_cpu_attr_groups;
	if (cpu->hotpluggable)
		cpu->dev.groups = hotplugable_cpu_attr_groups;
	error = device_register(&cpu->dev);
	if (error) {
		put_device(&cpu->dev);
		return error;
	}

	per_cpu(cpu_sys_devices, num) = &cpu->dev;
	register_cpu_under_node(num, cpu_to_node(num));
	dev_pm_qos_expose_latency_limit(&cpu->dev,
					PM_QOS_RESUME_LATENCY_NO_CONSTRAINT);

	return 0;
}

struct device *get_cpu_device(unsigned int 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);
}

__printf(4, 0)
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 = -ENOMEM;

	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
	if (!dev)
		goto error;

	device_initialize(dev);
	dev->parent = parent;
	dev->groups = groups;
	dev->release = device_create_release;
	device_set_pm_not_required(dev);
	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_CRASH_HOTPLUG
	&dev_attr_crash_hotplug.attr,
#endif
#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
	&dev_attr_modalias.attr,
#endif
	NULL
};

static const 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 int cpu)
{
	struct device *dev = get_cpu_device(cpu);
	return dev && container_of(dev, struct cpu, dev)->hotpluggable
		&& tick_nohz_cpu_hotpluggable(cpu);
}
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
}

#ifdef CONFIG_GENERIC_CPU_VULNERABILITIES
static ssize_t cpu_show_not_affected(struct device *dev,
			      struct device_attribute *attr, char *buf)
{
	return sysfs_emit(buf, "Not affected\n");
}

#define CPU_SHOW_VULN_FALLBACK(func)					\
	ssize_t cpu_show_##func(struct device *,			\
				  struct device_attribute *, char *)	\
		 __attribute__((weak, alias("cpu_show_not_affected")))

CPU_SHOW_VULN_FALLBACK(meltdown);
CPU_SHOW_VULN_FALLBACK(spectre_v1);
CPU_SHOW_VULN_FALLBACK(spectre_v2);
CPU_SHOW_VULN_FALLBACK(spec_store_bypass);
CPU_SHOW_VULN_FALLBACK(l1tf);
CPU_SHOW_VULN_FALLBACK(mds);
CPU_SHOW_VULN_FALLBACK(tsx_async_abort);
CPU_SHOW_VULN_FALLBACK(itlb_multihit);
CPU_SHOW_VULN_FALLBACK(srbds);
CPU_SHOW_VULN_FALLBACK(mmio_stale_data);
CPU_SHOW_VULN_FALLBACK(retbleed);
CPU_SHOW_VULN_FALLBACK(spec_rstack_overflow);
CPU_SHOW_VULN_FALLBACK(gds);

static DEVICE_ATTR(meltdown, 0444, cpu_show_meltdown, NULL);
static DEVICE_ATTR(spectre_v1, 0444, cpu_show_spectre_v1, NULL);
static DEVICE_ATTR(spectre_v2, 0444, cpu_show_spectre_v2, NULL);
static DEVICE_ATTR(spec_store_bypass, 0444, cpu_show_spec_store_bypass, NULL);
static DEVICE_ATTR(l1tf, 0444, cpu_show_l1tf, NULL);
static DEVICE_ATTR(mds, 0444, cpu_show_mds, NULL);
static DEVICE_ATTR(tsx_async_abort, 0444, cpu_show_tsx_async_abort, NULL);
static DEVICE_ATTR(itlb_multihit, 0444, cpu_show_itlb_multihit, NULL);
static DEVICE_ATTR(srbds, 0444, cpu_show_srbds, NULL);
static DEVICE_ATTR(mmio_stale_data, 0444, cpu_show_mmio_stale_data, NULL);
static DEVICE_ATTR(retbleed, 0444, cpu_show_retbleed, NULL);
static DEVICE_ATTR(spec_rstack_overflow, 0444, cpu_show_spec_rstack_overflow, NULL);
static DEVICE_ATTR(gather_data_sampling, 0444, cpu_show_gds, NULL);

static struct attribute *cpu_root_vulnerabilities_attrs[] = {
	&dev_attr_meltdown.attr,
	&dev_attr_spectre_v1.attr,
	&dev_attr_spectre_v2.attr,
	&dev_attr_spec_store_bypass.attr,
	&dev_attr_l1tf.attr,
	&dev_attr_mds.attr,
	&dev_attr_tsx_async_abort.attr,
	&dev_attr_itlb_multihit.attr,
	&dev_attr_srbds.attr,
	&dev_attr_mmio_stale_data.attr,
	&dev_attr_retbleed.attr,
	&dev_attr_spec_rstack_overflow.attr,
	&dev_attr_gather_data_sampling.attr,
	NULL
};

static const struct attribute_group cpu_root_vulnerabilities_group = {
	.name  = "vulnerabilities",
	.attrs = cpu_root_vulnerabilities_attrs,
};

static void __init cpu_register_vulnerabilities(void)
{
	struct device *dev = bus_get_dev_root(&cpu_subsys);

	if (dev) {
		if (sysfs_create_group(&dev->kobj, &cpu_root_vulnerabilities_group))
			pr_err("Unable to register CPU vulnerabilities\n");
		put_device(dev);
	}
}

#else
static inline void cpu_register_vulnerabilities(void) { }
#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();
	cpu_register_vulnerabilities();
}
Commit	Line	Data
989d42e8	1	// SPDX-License-Identifier: GPL-2.0
1da177e4	2	/*
8a25a2fd	3	* CPU subsystem support
1da177e4 LT	4	*/
1da177e4 LT	5
024f7846	6	#include <linux/kernel.h>
1da177e4 LT	7	#include <linux/module.h>
1da177e4 LT	8	#include <linux/init.h>
f6a57033	9	#include <linux/sched.h>
1da177e4 LT	10	#include <linux/cpu.h>
	11	#include <linux/topology.h>
	12	#include <linux/device.h>
76b67ed9	13	#include <linux/node.h>
5a0e3ad6	14	#include <linux/gfp.h>
fad12ac8	15	#include <linux/slab.h>
9f13a1fd	16	#include <linux/percpu.h>
ac212b69	17	#include <linux/acpi.h>
f86e4718	18	#include <linux/of.h>
67bad2fd	19	#include <linux/cpufeature.h>
6570a9a1	20	#include <linux/tick.h>
37efa4b4	21	#include <linux/pm_qos.h>
1fd7ab3f	22	#include <linux/delay.h>
edb93821	23	#include <linux/sched/isolation.h>
1da177e4	24
a1bdc7aa	25	#include "base.h"
1da177e4	26
8a25a2fd	27	static DEFINE_PER_CPU(struct device *, cpu_sys_devices);
ad74557a	28
ac212b69 RW	29	static int cpu_subsys_match(struct device dev, struct device_driver drv)
	30	{
	31	/* ACPI style match is the only one that may succeed. */
	32	if (acpi_driver_match_device(dev, drv))
	33	return 1;
	34
	35	return 0;
	36	}
	37
1da177e4	38	#ifdef CONFIG_HOTPLUG_CPU
34640468 YI	39	static void change_cpu_under_node(struct cpu *cpu,
	40	unsigned int from_nid, unsigned int to_nid)
	41	{
	42	int cpuid = cpu->dev.id;
	43	unregister_cpu_under_node(cpuid, from_nid);
	44	register_cpu_under_node(cpuid, to_nid);
	45	cpu->node_id = to_nid;
	46	}
	47
eda5867b	48	static int cpu_subsys_online(struct device *dev)
1da177e4	49	{
8a25a2fd	50	struct cpu *cpu = container_of(dev, struct cpu, dev);
0902a904 RW	51	int cpuid = dev->id;
0902a904 RW	52	int from_nid, to_nid;
6dedcca6	53	int ret;
1fd7ab3f	54	int retries = 0;
1da177e4	55
0902a904	56	from_nid = cpu_to_node(cpuid);
c7991b0b	57	if (from_nid == NUMA_NO_NODE)
6dedcca6	58	return -ENODEV;
c7991b0b	59
1fd7ab3f	60	retry:
33c3736e	61	ret = cpu_device_up(dev);
1fd7ab3f WL	62
	63	/*
	64	* If -EBUSY is returned, it is likely that hotplug is temporarily
	65	* disabled when cpu_hotplug_disable() was called. This condition is
	66	* transient. So we retry after waiting for an exponentially
	67	* increasing delay up to a total of at least 620ms as some PCI
	68	* device initialization can take quite a while.
	69	*/
	70	if (ret == -EBUSY) {
	71	retries++;
	72	if (retries > 5)
	73	return ret;
	74	msleep(10 * (1 << retries));
	75	goto retry;
	76	}
	77
0902a904 RW	78	/*
	79	* When hot adding memory to memoryless node and enabling a cpu
	80	* on the node, node number of the cpu may internally change.
	81	*/
	82	to_nid = cpu_to_node(cpuid);
	83	if (from_nid != to_nid)
	84	change_cpu_under_node(cpu, from_nid, to_nid);
1da177e4	85
0902a904	86	return ret;
1da177e4 LT	87	}
1da177e4 LT	88
0902a904	89	static int cpu_subsys_offline(struct device *dev)
1da177e4	90	{
33c3736e	91	return cpu_device_down(dev);
1da177e4	92	}
1c4e2d70	93
76b67ed9	94	void unregister_cpu(struct cpu *cpu)
1da177e4	95	{
8a25a2fd	96	int logical_cpu = cpu->dev.id;
1da177e4	97
76b67ed9 KH	98	unregister_cpu_under_node(logical_cpu, cpu_to_node(logical_cpu));
76b67ed9 KH	99
8a25a2fd	100	device_unregister(&cpu->dev);
e37d05da	101	per_cpu(cpu_sys_devices, logical_cpu) = NULL;
1da177e4 LT	102	return;
1da177e4 LT	103	}
12633e80 NF	104
12633e80 NF	105	#ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
8a25a2fd KS	106	static ssize_t cpu_probe_store(struct device *dev,
8a25a2fd KS	107	struct device_attribute *attr,
67fc233f	108	const char *buf,
12633e80 NF	109	size_t count)
12633e80 NF	110	{
574b851e TK	111	ssize_t cnt;
	112	int ret;
	113
	114	ret = lock_device_hotplug_sysfs();
	115	if (ret)
	116	return ret;
	117
	118	cnt = arch_cpu_probe(buf, count);
	119
	120	unlock_device_hotplug();
	121	return cnt;
12633e80 NF	122	}
12633e80 NF	123
8a25a2fd KS	124	static ssize_t cpu_release_store(struct device *dev,
8a25a2fd KS	125	struct device_attribute *attr,
67fc233f	126	const char *buf,
12633e80 NF	127	size_t count)
12633e80 NF	128	{
574b851e TK	129	ssize_t cnt;
	130	int ret;
	131
	132	ret = lock_device_hotplug_sysfs();
	133	if (ret)
	134	return ret;
	135
	136	cnt = arch_cpu_release(buf, count);
	137
	138	unlock_device_hotplug();
	139	return cnt;
12633e80 NF	140	}
12633e80 NF	141
8a25a2fd KS	142	static DEVICE_ATTR(probe, S_IWUSR, NULL, cpu_probe_store);
8a25a2fd KS	143	static DEVICE_ATTR(release, S_IWUSR, NULL, cpu_release_store);
12633e80	144	#endif /* CONFIG_ARCH_CPU_PROBE_RELEASE */
1da177e4 LT	145	#endif /* CONFIG_HOTPLUG_CPU */
1da177e4 LT	146
4e9e2e4c	147	#ifdef CONFIG_KEXEC_CORE
51be5606 VG	148	#include <linux/kexec.h>
51be5606 VG	149
948b3edb JP	150	static ssize_t crash_notes_show(struct device *dev,
948b3edb JP	151	struct device_attribute *attr,
4a0b2b4d	152	char *buf)
51be5606	153	{
8a25a2fd	154	struct cpu *cpu = container_of(dev, struct cpu, dev);
51be5606 VG	155	unsigned long long addr;
	156	int cpunum;
	157
8a25a2fd	158	cpunum = cpu->dev.id;
51be5606 VG	159
	160	/*
	161	* Might be reading other cpu's data based on which cpu read thread
	162	* has been scheduled. But cpu data (memory) is allocated once during
	163	* boot up and this data does not change there after. Hence this
	164	* operation should be safe. No locking required.
	165	*/
3b034b0d	166	addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpunum));
948b3edb JP	167
948b3edb JP	168	return sysfs_emit(buf, "%llx\n", addr);
51be5606	169	}
948b3edb	170	static DEVICE_ATTR_ADMIN_RO(crash_notes);
eca4549f	171
948b3edb	172	static ssize_t crash_notes_size_show(struct device *dev,
eca4549f ZY	173	struct device_attribute *attr,
	174	char *buf)
	175	{
948b3edb	176	return sysfs_emit(buf, "%zu\n", sizeof(note_buf_t));
eca4549f	177	}
948b3edb	178	static DEVICE_ATTR_ADMIN_RO(crash_notes_size);
c055da9f IM	179
	180	static struct attribute *crash_note_cpu_attrs[] = {
	181	&dev_attr_crash_notes.attr,
	182	&dev_attr_crash_notes_size.attr,
	183	NULL
	184	};
	185
5a576764	186	static const struct attribute_group crash_note_cpu_attr_group = {
c055da9f IM	187	.attrs = crash_note_cpu_attrs,
	188	};
	189	#endif
	190
	191	static const struct attribute_group *common_cpu_attr_groups[] = {
4e9e2e4c	192	#ifdef CONFIG_KEXEC_CORE
c055da9f	193	&crash_note_cpu_attr_group,
51be5606	194	#endif
c055da9f IM	195	NULL
c055da9f IM	196	};
51be5606	197
1c4e2d70	198	static const struct attribute_group *hotplugable_cpu_attr_groups[] = {
4e9e2e4c	199	#ifdef CONFIG_KEXEC_CORE
1c4e2d70	200	&crash_note_cpu_attr_group,
1c4e2d70 IM	201	#endif
	202	NULL
	203	};
	204
9d1fe323 MT	205	/*
	206	* Print cpu online, possible, present, and system maps
	207	*/
265d2e2e AK	208
265d2e2e AK	209	struct cpu_attr {
8a25a2fd	210	struct device_attribute attr;
848e2391	211	const struct cpumask *const map;
265d2e2e AK	212	};
265d2e2e AK	213
8a25a2fd KS	214	static ssize_t show_cpus_attr(struct device *dev,
8a25a2fd KS	215	struct device_attribute *attr,
265d2e2e	216	char *buf)
9d1fe323	217	{
265d2e2e	218	struct cpu_attr *ca = container_of(attr, struct cpu_attr, attr);
9d1fe323	219
848e2391	220	return cpumap_print_to_pagebuf(true, buf, ca->map);
9d1fe323 MT	221	}
9d1fe323 MT	222
8a25a2fd KS	223	#define _CPU_ATTR(name, map) \
8a25a2fd KS	224	{ __ATTR(name, 0444, show_cpus_attr, NULL), map }
9d1fe323	225
8a25a2fd	226	/* Keep in sync with cpu_subsys_attrs */
265d2e2e	227	static struct cpu_attr cpu_attrs[] = {
848e2391 RV	228	_CPU_ATTR(online, &__cpu_online_mask),
	229	_CPU_ATTR(possible, &__cpu_possible_mask),
	230	_CPU_ATTR(present, &__cpu_present_mask),
265d2e2e	231	};
9d1fe323	232
e057d7ae MT	233	/*
	234	* Print values for NR_CPUS and offlined cpus
	235	*/
8a25a2fd KS	236	static ssize_t print_cpus_kernel_max(struct device *dev,
8a25a2fd KS	237	struct device_attribute attr, char buf)
e057d7ae	238	{
aa838896	239	return sysfs_emit(buf, "%d\n", NR_CPUS - 1);
e057d7ae	240	}
8a25a2fd	241	static DEVICE_ATTR(kernel_max, 0444, print_cpus_kernel_max, NULL);
e057d7ae MT	242
	243	/* arch-optional setting to enable display of offline cpus >= nr_cpu_ids */
	244	unsigned int total_cpus;
	245
8a25a2fd KS	246	static ssize_t print_cpus_offline(struct device *dev,
8a25a2fd KS	247	struct device_attribute attr, char buf)
e057d7ae	248	{
948b3edb	249	int len = 0;
e057d7ae MT	250	cpumask_var_t offline;
	251
	252	/* display offline cpus < nr_cpu_ids */
	253	if (!alloc_cpumask_var(&offline, GFP_KERNEL))
	254	return -ENOMEM;
cdc6e3d3	255	cpumask_andnot(offline, cpu_possible_mask, cpu_online_mask);
948b3edb	256	len += sysfs_emit_at(buf, len, "%*pbl", cpumask_pr_args(offline));
e057d7ae MT	257	free_cpumask_var(offline);
	258
	259	/* display offline cpus >= nr_cpu_ids */
	260	if (total_cpus && nr_cpu_ids < total_cpus) {
948b3edb	261	len += sysfs_emit_at(buf, len, ",");
e057d7ae MT	262
e057d7ae MT	263	if (nr_cpu_ids == total_cpus-1)
948b3edb	264	len += sysfs_emit_at(buf, len, "%u", nr_cpu_ids);
e057d7ae	265	else
948b3edb JP	266	len += sysfs_emit_at(buf, len, "%u-%d",
948b3edb JP	267	nr_cpu_ids, total_cpus - 1);
e057d7ae MT	268	}
e057d7ae MT	269
948b3edb JP	270	len += sysfs_emit_at(buf, len, "\n");
	271
	272	return len;
e057d7ae	273	}
8a25a2fd	274	static DEVICE_ATTR(offline, 0444, print_cpus_offline, NULL);
e057d7ae	275
59f30abe RR	276	static ssize_t print_cpus_isolated(struct device *dev,
	277	struct device_attribute attr, char buf)
	278	{
948b3edb	279	int len;
edb93821	280	cpumask_var_t isolated;
59f30abe	281
edb93821 FW	282	if (!alloc_cpumask_var(&isolated, GFP_KERNEL))
	283	return -ENOMEM;
	284
	285	cpumask_andnot(isolated, cpu_possible_mask,
04d4e665	286	housekeeping_cpumask(HK_TYPE_DOMAIN));
948b3edb	287	len = sysfs_emit(buf, "%*pbl\n", cpumask_pr_args(isolated));
edb93821 FW	288
edb93821 FW	289	free_cpumask_var(isolated);
59f30abe	290
948b3edb	291	return len;
59f30abe RR	292	}
	293	static DEVICE_ATTR(isolated, 0444, print_cpus_isolated, NULL);
	294
6570a9a1 RR	295	#ifdef CONFIG_NO_HZ_FULL
6570a9a1 RR	296	static ssize_t print_cpus_nohz_full(struct device *dev,
948b3edb	297	struct device_attribute attr, char buf)
6570a9a1	298	{
aa838896	299	return sysfs_emit(buf, "%*pbl\n", cpumask_pr_args(tick_nohz_full_mask));
6570a9a1 RR	300	}
	301	static DEVICE_ATTR(nohz_full, 0444, print_cpus_nohz_full, NULL);
	302	#endif
	303
88a6f899 ED	304	#ifdef CONFIG_CRASH_HOTPLUG
	305	static ssize_t crash_hotplug_show(struct device *dev,
	306	struct device_attribute *attr,
	307	char *buf)
	308	{
	309	return sysfs_emit(buf, "%d\n", crash_hotplug_cpu_support());
	310	}
	311	static DEVICE_ATTR_ADMIN_RO(crash_hotplug);
	312	#endif
	313
2885e25c GKH	314	static void cpu_device_release(struct device *dev)
	315	{
	316	/*
	317	* This is an empty function to prevent the driver core from spitting a
	318	* warning at us. Yes, I know this is directly opposite of what the
	319	* documentation for the driver core and kobjects say, and the author
	320	* of this code has already been publically ridiculed for doing
	321	* something as foolish as this. However, at this point in time, it is
	322	* the only way to handle the issue of statically allocated cpu
	323	* devices. The different architectures will have their cpu device
	324	* code reworked to properly handle this in the near future, so this
	325	* function will then be changed to correctly free up the memory held
	326	* by the cpu device.
	327	*
	328	* Never copy this way of doing things, or you too will be made fun of
30a4840a	329	* on the linux-kernel list, you have been warned.
2885e25c GKH	330	*/
	331	}
	332
67bad2fd AB	333	#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
	334	static ssize_t print_cpu_modalias(struct device *dev,
	335	struct device_attribute *attr,
	336	char *buf)
	337	{
948b3edb	338	int len = 0;
67bad2fd AB	339	u32 i;
67bad2fd AB	340
948b3edb JP	341	len += sysfs_emit_at(buf, len,
	342	"cpu:type:" CPU_FEATURE_TYPEFMT ":feature:",
	343	CPU_FEATURE_TYPEVAL);
67bad2fd AB	344
	345	for (i = 0; i < MAX_CPU_FEATURES; i++)
	346	if (cpu_have_feature(i)) {
948b3edb	347	if (len + sizeof(",XXXX\n") >= PAGE_SIZE) {
67bad2fd AB	348	WARN(1, "CPU features overflow page\n");
	349	break;
	350	}
948b3edb	351	len += sysfs_emit_at(buf, len, ",%04X", i);
67bad2fd	352	}
948b3edb JP	353	len += sysfs_emit_at(buf, len, "\n");
948b3edb JP	354	return len;
67bad2fd	355	}
67bad2fd	356
2a81ada3	357	static int cpu_uevent(const struct device dev, struct kobj_uevent_env env)
67bad2fd AB	358	{
	359	char *buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
	360	if (buf) {
	361	print_cpu_modalias(NULL, NULL, buf);
	362	add_uevent_var(env, "MODALIAS=%s", buf);
	363	kfree(buf);
	364	}
	365	return 0;
	366	}
	367	#endif
	368
2bc19066 GKH	369	struct bus_type cpu_subsys = {
	370	.name = "cpu",
	371	.dev_name = "cpu",
	372	.match = cpu_subsys_match,
	373	#ifdef CONFIG_HOTPLUG_CPU
	374	.online = cpu_subsys_online,
	375	.offline = cpu_subsys_offline,
	376	#endif
	377	#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
	378	.uevent = cpu_uevent,
	379	#endif
	380	};
	381	EXPORT_SYMBOL_GPL(cpu_subsys);
	382
1da177e4	383	/*
405ae7d3	384	* register_cpu - Setup a sysfs device for a CPU.
72486f1f SS	385	* @cpu - cpu->hotpluggable field set to 1 will generate a control file in
72486f1f SS	386	* sysfs for this CPU.
1da177e4 LT	387	* @num - CPU number to use when creating the device.
	388	*
	389	* Initialize and register the CPU device.
	390	*/
a83048eb	391	int register_cpu(struct cpu *cpu, int num)
1da177e4 LT	392	{
1da177e4 LT	393	int error;
76b67ed9	394
8a25a2fd	395	cpu->node_id = cpu_to_node(num);
29bb5d4f	396	memset(&cpu->dev, 0x00, sizeof(struct device));
8a25a2fd KS	397	cpu->dev.id = num;
8a25a2fd KS	398	cpu->dev.bus = &cpu_subsys;
2885e25c	399	cpu->dev.release = cpu_device_release;
0902a904	400	cpu->dev.offline_disabled = !cpu->hotpluggable;
1001b4d4	401	cpu->dev.offline = !cpu_online(num);
f86e4718	402	cpu->dev.of_node = of_get_cpu_node(num, NULL);
c055da9f	403	cpu->dev.groups = common_cpu_attr_groups;
1c4e2d70 IM	404	if (cpu->hotpluggable)
1c4e2d70 IM	405	cpu->dev.groups = hotplugable_cpu_attr_groups;
8a25a2fd	406	error = device_register(&cpu->dev);
3aaba245 AY	407	if (error) {
3aaba245 AY	408	put_device(&cpu->dev);
59fffa34	409	return error;
3aaba245	410	}
51be5606	411
59fffa34 AS	412	per_cpu(cpu_sys_devices, num) = &cpu->dev;
59fffa34 AS	413	register_cpu_under_node(num, cpu_to_node(num));
0759e80b RW	414	dev_pm_qos_expose_latency_limit(&cpu->dev,
0759e80b RW	415	PM_QOS_RESUME_LATENCY_NO_CONSTRAINT);
59fffa34 AS	416
59fffa34 AS	417	return 0;
1da177e4 LT	418	}
1da177e4 LT	419
e7deeb9d	420	struct device *get_cpu_device(unsigned int cpu)
ad74557a	421	{
e37d05da MT	422	if (cpu < nr_cpu_ids && cpu_possible(cpu))
e37d05da MT	423	return per_cpu(cpu_sys_devices, cpu);
ad74557a AR	424	else
	425	return NULL;
	426	}
8a25a2fd KS	427	EXPORT_SYMBOL_GPL(get_cpu_device);
8a25a2fd KS	428
3d52943b SH	429	static void device_create_release(struct device *dev)
	430	{
	431	kfree(dev);
	432	}
	433
fa548d79	434	__printf(4, 0)
3d52943b SH	435	static struct device *
	436	__cpu_device_create(struct device parent, void drvdata,
	437	const struct attribute_group **groups,
	438	const char *fmt, va_list args)
	439	{
	440	struct device *dev = NULL;
6b72cf12	441	int retval = -ENOMEM;
3d52943b SH	442
3d52943b SH	443	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
6b72cf12	444	if (!dev)
3d52943b	445	goto error;
3d52943b SH	446
	447	device_initialize(dev);
	448	dev->parent = parent;
	449	dev->groups = groups;
	450	dev->release = device_create_release;
85945c28	451	device_set_pm_not_required(dev);
3d52943b SH	452	dev_set_drvdata(dev, drvdata);
	453
	454	retval = kobject_set_name_vargs(&dev->kobj, fmt, args);
	455	if (retval)
	456	goto error;
	457
	458	retval = device_add(dev);
	459	if (retval)
	460	goto error;
	461
	462	return dev;
	463
	464	error:
	465	put_device(dev);
	466	return ERR_PTR(retval);
	467	}
	468
	469	struct device cpu_device_create(struct device parent, void *drvdata,
	470	const struct attribute_group **groups,
	471	const char *fmt, ...)
	472	{
	473	va_list vargs;
	474	struct device *dev;
	475
	476	va_start(vargs, fmt);
	477	dev = __cpu_device_create(parent, drvdata, groups, fmt, vargs);
	478	va_end(vargs);
	479	return dev;
	480	}
	481	EXPORT_SYMBOL_GPL(cpu_device_create);
	482
2b9c1f03	483	#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
67bad2fd	484	static DEVICE_ATTR(modalias, 0444, print_cpu_modalias, NULL);
fad12ac8 TR	485	#endif
fad12ac8 TR	486
8a25a2fd KS	487	static struct attribute *cpu_root_attrs[] = {
	488	#ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
	489	&dev_attr_probe.attr,
	490	&dev_attr_release.attr,
	491	#endif
	492	&cpu_attrs[0].attr.attr,
	493	&cpu_attrs[1].attr.attr,
	494	&cpu_attrs[2].attr.attr,
	495	&dev_attr_kernel_max.attr,
	496	&dev_attr_offline.attr,
59f30abe	497	&dev_attr_isolated.attr,
6570a9a1 RR	498	#ifdef CONFIG_NO_HZ_FULL
	499	&dev_attr_nohz_full.attr,
	500	#endif
88a6f899 ED	501	#ifdef CONFIG_CRASH_HOTPLUG
	502	&dev_attr_crash_hotplug.attr,
	503	#endif
2b9c1f03	504	#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
fad12ac8 TR	505	&dev_attr_modalias.attr,
fad12ac8 TR	506	#endif
8a25a2fd KS	507	NULL
	508	};
	509
5a576764	510	static const struct attribute_group cpu_root_attr_group = {
8a25a2fd KS	511	.attrs = cpu_root_attrs,
	512	};
	513
	514	static const struct attribute_group *cpu_root_attr_groups[] = {
	515	&cpu_root_attr_group,
	516	NULL,
	517	};
1da177e4	518
e7deeb9d	519	bool cpu_is_hotpluggable(unsigned int cpu)
2987557f	520	{
7affca35	521	struct device *dev = get_cpu_device(cpu);
58d76682 JFG	522	return dev && container_of(dev, struct cpu, dev)->hotpluggable
58d76682 JFG	523	&& tick_nohz_cpu_hotpluggable(cpu);
2987557f JT	524	}
	525	EXPORT_SYMBOL_GPL(cpu_is_hotpluggable);
	526
9f13a1fd BH	527	#ifdef CONFIG_GENERIC_CPU_DEVICES
	528	static DEFINE_PER_CPU(struct cpu, cpu_devices);
	529	#endif
	530
	531	static void __init cpu_dev_register_generic(void)
	532	{
	533	#ifdef CONFIG_GENERIC_CPU_DEVICES
	534	int i;
	535
	536	for_each_possible_cpu(i) {
	537	if (register_cpu(&per_cpu(cpu_devices, i), i))
	538	panic("Failed to register CPU device");
	539	}
	540	#endif
	541	}
	542
87590ce6	543	#ifdef CONFIG_GENERIC_CPU_VULNERABILITIES
6524c798	544	static ssize_t cpu_show_not_affected(struct device *dev,
7e5b3c26 MG	545	struct device_attribute attr, char buf)
7e5b3c26 MG	546	{
aa838896	547	return sysfs_emit(buf, "Not affected\n");
7e5b3c26 MG	548	}
7e5b3c26 MG	549
0fddfe33 BPA	550	#define CPU_SHOW_VULN_FALLBACK(func) \
	551	ssize_t cpu_show_##func(struct device *, \
	552	struct device_attribute , char ) \
	553	__attribute__((weak, alias("cpu_show_not_affected")))
	554
	555	CPU_SHOW_VULN_FALLBACK(meltdown);
	556	CPU_SHOW_VULN_FALLBACK(spectre_v1);
	557	CPU_SHOW_VULN_FALLBACK(spectre_v2);
	558	CPU_SHOW_VULN_FALLBACK(spec_store_bypass);
	559	CPU_SHOW_VULN_FALLBACK(l1tf);
	560	CPU_SHOW_VULN_FALLBACK(mds);
	561	CPU_SHOW_VULN_FALLBACK(tsx_async_abort);
	562	CPU_SHOW_VULN_FALLBACK(itlb_multihit);
	563	CPU_SHOW_VULN_FALLBACK(srbds);
	564	CPU_SHOW_VULN_FALLBACK(mmio_stale_data);
	565	CPU_SHOW_VULN_FALLBACK(retbleed);
	566	CPU_SHOW_VULN_FALLBACK(spec_rstack_overflow);
3477144c	567	CPU_SHOW_VULN_FALLBACK(gds);
fb3bd914	568
87590ce6 TG	569	static DEVICE_ATTR(meltdown, 0444, cpu_show_meltdown, NULL);
	570	static DEVICE_ATTR(spectre_v1, 0444, cpu_show_spectre_v1, NULL);
	571	static DEVICE_ATTR(spectre_v2, 0444, cpu_show_spectre_v2, NULL);
c456442c	572	static DEVICE_ATTR(spec_store_bypass, 0444, cpu_show_spec_store_bypass, NULL);
17dbca11	573	static DEVICE_ATTR(l1tf, 0444, cpu_show_l1tf, NULL);
8a4b06d3	574	static DEVICE_ATTR(mds, 0444, cpu_show_mds, NULL);
6608b45a	575	static DEVICE_ATTR(tsx_async_abort, 0444, cpu_show_tsx_async_abort, NULL);
db4d30fb	576	static DEVICE_ATTR(itlb_multihit, 0444, cpu_show_itlb_multihit, NULL);
7e5b3c26	577	static DEVICE_ATTR(srbds, 0444, cpu_show_srbds, NULL);
8d50cdf8	578	static DEVICE_ATTR(mmio_stale_data, 0444, cpu_show_mmio_stale_data, NULL);
6b80b59b	579	static DEVICE_ATTR(retbleed, 0444, cpu_show_retbleed, NULL);
fb3bd914	580	static DEVICE_ATTR(spec_rstack_overflow, 0444, cpu_show_spec_rstack_overflow, NULL);
3477144c	581	static DEVICE_ATTR(gather_data_sampling, 0444, cpu_show_gds, NULL);
87590ce6 TG	582
	583	static struct attribute *cpu_root_vulnerabilities_attrs[] = {
	584	&dev_attr_meltdown.attr,
	585	&dev_attr_spectre_v1.attr,
	586	&dev_attr_spectre_v2.attr,
c456442c	587	&dev_attr_spec_store_bypass.attr,
17dbca11	588	&dev_attr_l1tf.attr,
8a4b06d3	589	&dev_attr_mds.attr,
6608b45a	590	&dev_attr_tsx_async_abort.attr,
db4d30fb	591	&dev_attr_itlb_multihit.attr,
7e5b3c26	592	&dev_attr_srbds.attr,
8d50cdf8	593	&dev_attr_mmio_stale_data.attr,
6b80b59b	594	&dev_attr_retbleed.attr,
fb3bd914	595	&dev_attr_spec_rstack_overflow.attr,
8974eb58	596	&dev_attr_gather_data_sampling.attr,
87590ce6 TG	597	NULL
	598	};
	599
	600	static const struct attribute_group cpu_root_vulnerabilities_group = {
	601	.name = "vulnerabilities",
	602	.attrs = cpu_root_vulnerabilities_attrs,
	603	};
	604
	605	static void __init cpu_register_vulnerabilities(void)
	606	{
8c99377e GKH	607	struct device *dev = bus_get_dev_root(&cpu_subsys);
	608
	609	if (dev) {
	610	if (sysfs_create_group(&dev->kobj, &cpu_root_vulnerabilities_group))
	611	pr_err("Unable to register CPU vulnerabilities\n");
	612	put_device(dev);
	613	}
87590ce6 TG	614	}
	615
	616	#else
	617	static inline void cpu_register_vulnerabilities(void) { }
	618	#endif
	619
024f7846	620	void __init cpu_dev_init(void)
1da177e4	621	{
024f7846 BH	622	if (subsys_system_register(&cpu_subsys, cpu_root_attr_groups))
024f7846 BH	623	panic("Failed to register CPU subsystem");
8a25a2fd	624
9f13a1fd	625	cpu_dev_register_generic();
87590ce6	626	cpu_register_vulnerabilities();
1da177e4	627	}