[mirror_ubuntu-eoan-kernel.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/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;

	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 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, "%u", nr_cpu_ids);
		else
			n += snprintf(&buf[n], len - n, "%u-%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;
	cpumask_var_t isolated;

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

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

	free_cpumask_var(isolated);

	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) {
		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 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 = -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;
	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_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
}

#ifdef CONFIG_GENERIC_CPU_VULNERABILITIES

ssize_t __weak cpu_show_meltdown(struct device *dev,
				 struct device_attribute *attr, char *buf)
{
	return sprintf(buf, "Not affected\n");
}

ssize_t __weak cpu_show_spectre_v1(struct device *dev,
				   struct device_attribute *attr, char *buf)
{
	return sprintf(buf, "Not affected\n");
}

ssize_t __weak cpu_show_spectre_v2(struct device *dev,
				   struct device_attribute *attr, char *buf)
{
	return sprintf(buf, "Not affected\n");
}

ssize_t __weak cpu_show_spec_store_bypass(struct device *dev,
					  struct device_attribute *attr, char *buf)
{
	return sprintf(buf, "Not affected\n");
}

ssize_t __weak cpu_show_l1tf(struct device *dev,
			     struct device_attribute *attr, char *buf)
{
	return sprintf(buf, "Not affected\n");
}

ssize_t __weak cpu_show_mds(struct device *dev,
			    struct device_attribute *attr, char *buf)
{
	return sprintf(buf, "Not affected\n");
}

ssize_t __weak cpu_show_tsx_async_abort(struct device *dev,
					struct device_attribute *attr,
					char *buf)
{
	return sprintf(buf, "Not affected\n");
}

ssize_t __weak cpu_show_itlb_multihit(struct device *dev,
			    struct device_attribute *attr, char *buf)
{
	return sprintf(buf, "Not affected\n");
}

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 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,
	NULL
};

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

static void __init cpu_register_vulnerabilities(void)
{
	if (sysfs_create_group(&cpu_subsys.dev_root->kobj,
			       &cpu_root_vulnerabilities_group))
		pr_err("Unable to register CPU vulnerabilities\n");
}

#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>
edb93821	22	#include <linux/sched/isolation.h>
1da177e4	23
a1bdc7aa	24	#include "base.h"
1da177e4	25
8a25a2fd	26	static DEFINE_PER_CPU(struct device *, cpu_sys_devices);
ad74557a	27
ac212b69 RW	28	static int cpu_subsys_match(struct device dev, struct device_driver drv)
	29	{
	30	/* ACPI style match is the only one that may succeed. */
	31	if (acpi_driver_match_device(dev, drv))
	32	return 1;
	33
	34	return 0;
	35	}
	36
1da177e4	37	#ifdef CONFIG_HOTPLUG_CPU
34640468 YI	38	static void change_cpu_under_node(struct cpu *cpu,
	39	unsigned int from_nid, unsigned int to_nid)
	40	{
	41	int cpuid = cpu->dev.id;
	42	unregister_cpu_under_node(cpuid, from_nid);
	43	register_cpu_under_node(cpuid, to_nid);
	44	cpu->node_id = to_nid;
	45	}
	46
eda5867b	47	static int cpu_subsys_online(struct device *dev)
1da177e4	48	{
8a25a2fd	49	struct cpu *cpu = container_of(dev, struct cpu, dev);
0902a904 RW	50	int cpuid = dev->id;
0902a904 RW	51	int from_nid, to_nid;
6dedcca6	52	int ret;
1da177e4	53
0902a904	54	from_nid = cpu_to_node(cpuid);
c7991b0b	55	if (from_nid == NUMA_NO_NODE)
6dedcca6	56	return -ENODEV;
c7991b0b	57
0902a904 RW	58	ret = cpu_up(cpuid);
	59	/*
	60	* When hot adding memory to memoryless node and enabling a cpu
	61	* on the node, node number of the cpu may internally change.
	62	*/
	63	to_nid = cpu_to_node(cpuid);
	64	if (from_nid != to_nid)
	65	change_cpu_under_node(cpu, from_nid, to_nid);
1da177e4	66
0902a904	67	return ret;
1da177e4 LT	68	}
1da177e4 LT	69
0902a904	70	static int cpu_subsys_offline(struct device *dev)
1da177e4	71	{
6dedcca6	72	return cpu_down(dev->id);
1da177e4	73	}
1c4e2d70	74
76b67ed9	75	void unregister_cpu(struct cpu *cpu)
1da177e4	76	{
8a25a2fd	77	int logical_cpu = cpu->dev.id;
1da177e4	78
76b67ed9 KH	79	unregister_cpu_under_node(logical_cpu, cpu_to_node(logical_cpu));
76b67ed9 KH	80
8a25a2fd	81	device_unregister(&cpu->dev);
e37d05da	82	per_cpu(cpu_sys_devices, logical_cpu) = NULL;
1da177e4 LT	83	return;
1da177e4 LT	84	}
12633e80 NF	85
12633e80 NF	86	#ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
8a25a2fd KS	87	static ssize_t cpu_probe_store(struct device *dev,
8a25a2fd KS	88	struct device_attribute *attr,
67fc233f	89	const char *buf,
12633e80 NF	90	size_t count)
12633e80 NF	91	{
574b851e TK	92	ssize_t cnt;
	93	int ret;
	94
	95	ret = lock_device_hotplug_sysfs();
	96	if (ret)
	97	return ret;
	98
	99	cnt = arch_cpu_probe(buf, count);
	100
	101	unlock_device_hotplug();
	102	return cnt;
12633e80 NF	103	}
12633e80 NF	104
8a25a2fd KS	105	static ssize_t cpu_release_store(struct device *dev,
8a25a2fd KS	106	struct device_attribute *attr,
67fc233f	107	const char *buf,
12633e80 NF	108	size_t count)
12633e80 NF	109	{
574b851e TK	110	ssize_t cnt;
	111	int ret;
	112
	113	ret = lock_device_hotplug_sysfs();
	114	if (ret)
	115	return ret;
	116
	117	cnt = arch_cpu_release(buf, count);
	118
	119	unlock_device_hotplug();
	120	return cnt;
12633e80 NF	121	}
12633e80 NF	122
8a25a2fd KS	123	static DEVICE_ATTR(probe, S_IWUSR, NULL, cpu_probe_store);
8a25a2fd KS	124	static DEVICE_ATTR(release, S_IWUSR, NULL, cpu_release_store);
12633e80	125	#endif /* CONFIG_ARCH_CPU_PROBE_RELEASE */
1da177e4 LT	126	#endif /* CONFIG_HOTPLUG_CPU */
1da177e4 LT	127
0902a904 RW	128	struct bus_type cpu_subsys = {
	129	.name = "cpu",
	130	.dev_name = "cpu",
ac212b69	131	.match = cpu_subsys_match,
0902a904 RW	132	#ifdef CONFIG_HOTPLUG_CPU
	133	.online = cpu_subsys_online,
	134	.offline = cpu_subsys_offline,
	135	#endif
	136	};
	137	EXPORT_SYMBOL_GPL(cpu_subsys);
	138
51be5606 VG	139	#ifdef CONFIG_KEXEC
	140	#include <linux/kexec.h>
	141
8a25a2fd	142	static ssize_t show_crash_notes(struct device dev, struct device_attribute attr,
4a0b2b4d	143	char *buf)
51be5606	144	{
8a25a2fd	145	struct cpu *cpu = container_of(dev, struct cpu, dev);
51be5606 VG	146	ssize_t rc;
	147	unsigned long long addr;
	148	int cpunum;
	149
8a25a2fd	150	cpunum = cpu->dev.id;
51be5606 VG	151
	152	/*
	153	* Might be reading other cpu's data based on which cpu read thread
	154	* has been scheduled. But cpu data (memory) is allocated once during
	155	* boot up and this data does not change there after. Hence this
	156	* operation should be safe. No locking required.
	157	*/
3b034b0d	158	addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpunum));
51be5606	159	rc = sprintf(buf, "%Lx\n", addr);
51be5606 VG	160	return rc;
51be5606 VG	161	}
8a25a2fd	162	static DEVICE_ATTR(crash_notes, 0400, show_crash_notes, NULL);
eca4549f ZY	163
	164	static ssize_t show_crash_notes_size(struct device *dev,
	165	struct device_attribute *attr,
	166	char *buf)
	167	{
	168	ssize_t rc;
	169
bcfb87fb	170	rc = sprintf(buf, "%zu\n", sizeof(note_buf_t));
eca4549f ZY	171	return rc;
	172	}
	173	static DEVICE_ATTR(crash_notes_size, 0400, show_crash_notes_size, NULL);
c055da9f IM	174
	175	static struct attribute *crash_note_cpu_attrs[] = {
	176	&dev_attr_crash_notes.attr,
	177	&dev_attr_crash_notes_size.attr,
	178	NULL
	179	};
	180
	181	static struct attribute_group crash_note_cpu_attr_group = {
	182	.attrs = crash_note_cpu_attrs,
	183	};
	184	#endif
	185
	186	static const struct attribute_group *common_cpu_attr_groups[] = {
	187	#ifdef CONFIG_KEXEC
	188	&crash_note_cpu_attr_group,
51be5606	189	#endif
c055da9f IM	190	NULL
c055da9f IM	191	};
51be5606	192
1c4e2d70 IM	193	static const struct attribute_group *hotplugable_cpu_attr_groups[] = {
	194	#ifdef CONFIG_KEXEC
	195	&crash_note_cpu_attr_group,
1c4e2d70 IM	196	#endif
	197	NULL
	198	};
	199
9d1fe323 MT	200	/*
	201	* Print cpu online, possible, present, and system maps
	202	*/
265d2e2e AK	203
265d2e2e AK	204	struct cpu_attr {
8a25a2fd	205	struct device_attribute attr;
848e2391	206	const struct cpumask *const map;
265d2e2e AK	207	};
265d2e2e AK	208
8a25a2fd KS	209	static ssize_t show_cpus_attr(struct device *dev,
8a25a2fd KS	210	struct device_attribute *attr,
265d2e2e	211	char *buf)
9d1fe323	212	{
265d2e2e	213	struct cpu_attr *ca = container_of(attr, struct cpu_attr, attr);
9d1fe323	214
848e2391	215	return cpumap_print_to_pagebuf(true, buf, ca->map);
9d1fe323 MT	216	}
9d1fe323 MT	217
8a25a2fd KS	218	#define _CPU_ATTR(name, map) \
8a25a2fd KS	219	{ __ATTR(name, 0444, show_cpus_attr, NULL), map }
9d1fe323	220
8a25a2fd	221	/* Keep in sync with cpu_subsys_attrs */
265d2e2e	222	static struct cpu_attr cpu_attrs[] = {
848e2391 RV	223	_CPU_ATTR(online, &__cpu_online_mask),
	224	_CPU_ATTR(possible, &__cpu_possible_mask),
	225	_CPU_ATTR(present, &__cpu_present_mask),
265d2e2e	226	};
9d1fe323	227
e057d7ae MT	228	/*
	229	* Print values for NR_CPUS and offlined cpus
	230	*/
8a25a2fd KS	231	static ssize_t print_cpus_kernel_max(struct device *dev,
8a25a2fd KS	232	struct device_attribute attr, char buf)
e057d7ae	233	{
8fd2d2d5	234	int n = snprintf(buf, PAGE_SIZE-2, "%d\n", NR_CPUS - 1);
e057d7ae MT	235	return n;
e057d7ae MT	236	}
8a25a2fd	237	static DEVICE_ATTR(kernel_max, 0444, print_cpus_kernel_max, NULL);
e057d7ae MT	238
	239	/* arch-optional setting to enable display of offline cpus >= nr_cpu_ids */
	240	unsigned int total_cpus;
	241
8a25a2fd KS	242	static ssize_t print_cpus_offline(struct device *dev,
8a25a2fd KS	243	struct device_attribute attr, char buf)
e057d7ae MT	244	{
	245	int n = 0, len = PAGE_SIZE-2;
	246	cpumask_var_t offline;
	247
	248	/* display offline cpus < nr_cpu_ids */
	249	if (!alloc_cpumask_var(&offline, GFP_KERNEL))
	250	return -ENOMEM;
cdc6e3d3	251	cpumask_andnot(offline, cpu_possible_mask, cpu_online_mask);
f799b1a7	252	n = scnprintf(buf, len, "%*pbl", cpumask_pr_args(offline));
e057d7ae MT	253	free_cpumask_var(offline);
	254
	255	/* display offline cpus >= nr_cpu_ids */
	256	if (total_cpus && nr_cpu_ids < total_cpus) {
	257	if (n && n < len)
	258	buf[n++] = ',';
	259
	260	if (nr_cpu_ids == total_cpus-1)
9b130ad5	261	n += snprintf(&buf[n], len - n, "%u", nr_cpu_ids);
e057d7ae	262	else
9b130ad5	263	n += snprintf(&buf[n], len - n, "%u-%d",
e057d7ae MT	264	nr_cpu_ids, total_cpus-1);
	265	}
	266
	267	n += snprintf(&buf[n], len - n, "\n");
	268	return n;
	269	}
8a25a2fd	270	static DEVICE_ATTR(offline, 0444, print_cpus_offline, NULL);
e057d7ae	271
59f30abe RR	272	static ssize_t print_cpus_isolated(struct device *dev,
	273	struct device_attribute attr, char buf)
	274	{
	275	int n = 0, len = PAGE_SIZE-2;
edb93821	276	cpumask_var_t isolated;
59f30abe	277
edb93821 FW	278	if (!alloc_cpumask_var(&isolated, GFP_KERNEL))
	279	return -ENOMEM;
	280
	281	cpumask_andnot(isolated, cpu_possible_mask,
	282	housekeeping_cpumask(HK_FLAG_DOMAIN));
	283	n = scnprintf(buf, len, "%*pbl\n", cpumask_pr_args(isolated));
	284
	285	free_cpumask_var(isolated);
59f30abe RR	286
	287	return n;
	288	}
	289	static DEVICE_ATTR(isolated, 0444, print_cpus_isolated, NULL);
	290
6570a9a1 RR	291	#ifdef CONFIG_NO_HZ_FULL
	292	static ssize_t print_cpus_nohz_full(struct device *dev,
	293	struct device_attribute attr, char buf)
	294	{
	295	int n = 0, len = PAGE_SIZE-2;
	296
	297	n = scnprintf(buf, len, "%*pbl\n", cpumask_pr_args(tick_nohz_full_mask));
	298
	299	return n;
	300	}
	301	static DEVICE_ATTR(nohz_full, 0444, print_cpus_nohz_full, NULL);
	302	#endif
	303
2885e25c GKH	304	static void cpu_device_release(struct device *dev)
	305	{
	306	/*
	307	* This is an empty function to prevent the driver core from spitting a
	308	* warning at us. Yes, I know this is directly opposite of what the
	309	* documentation for the driver core and kobjects say, and the author
	310	* of this code has already been publically ridiculed for doing
	311	* something as foolish as this. However, at this point in time, it is
	312	* the only way to handle the issue of statically allocated cpu
	313	* devices. The different architectures will have their cpu device
	314	* code reworked to properly handle this in the near future, so this
	315	* function will then be changed to correctly free up the memory held
	316	* by the cpu device.
	317	*
	318	* Never copy this way of doing things, or you too will be made fun of
30a4840a	319	* on the linux-kernel list, you have been warned.
2885e25c GKH	320	*/
	321	}
	322
67bad2fd AB	323	#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
	324	static ssize_t print_cpu_modalias(struct device *dev,
	325	struct device_attribute *attr,
	326	char *buf)
	327	{
	328	ssize_t n;
	329	u32 i;
	330
	331	n = sprintf(buf, "cpu:type:" CPU_FEATURE_TYPEFMT ":feature:",
	332	CPU_FEATURE_TYPEVAL);
	333
	334	for (i = 0; i < MAX_CPU_FEATURES; i++)
	335	if (cpu_have_feature(i)) {
	336	if (PAGE_SIZE < n + sizeof(",XXXX\n")) {
	337	WARN(1, "CPU features overflow page\n");
	338	break;
	339	}
	340	n += sprintf(&buf[n], ",%04X", i);
	341	}
	342	buf[n++] = '\n';
	343	return n;
	344	}
67bad2fd AB	345
	346	static int cpu_uevent(struct device dev, struct kobj_uevent_env env)
	347	{
	348	char *buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
	349	if (buf) {
	350	print_cpu_modalias(NULL, NULL, buf);
	351	add_uevent_var(env, "MODALIAS=%s", buf);
	352	kfree(buf);
	353	}
	354	return 0;
	355	}
	356	#endif
	357
1da177e4	358	/*
405ae7d3	359	* register_cpu - Setup a sysfs device for a CPU.
72486f1f SS	360	* @cpu - cpu->hotpluggable field set to 1 will generate a control file in
72486f1f SS	361	* sysfs for this CPU.
1da177e4 LT	362	* @num - CPU number to use when creating the device.
	363	*
	364	* Initialize and register the CPU device.
	365	*/
a83048eb	366	int register_cpu(struct cpu *cpu, int num)
1da177e4 LT	367	{
1da177e4 LT	368	int error;
76b67ed9	369
8a25a2fd	370	cpu->node_id = cpu_to_node(num);
29bb5d4f	371	memset(&cpu->dev, 0x00, sizeof(struct device));
8a25a2fd KS	372	cpu->dev.id = num;
8a25a2fd KS	373	cpu->dev.bus = &cpu_subsys;
2885e25c	374	cpu->dev.release = cpu_device_release;
0902a904	375	cpu->dev.offline_disabled = !cpu->hotpluggable;
1001b4d4	376	cpu->dev.offline = !cpu_online(num);
f86e4718	377	cpu->dev.of_node = of_get_cpu_node(num, NULL);
2b9c1f03	378	#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
67bad2fd	379	cpu->dev.bus->uevent = cpu_uevent;
fad12ac8	380	#endif
c055da9f	381	cpu->dev.groups = common_cpu_attr_groups;
1c4e2d70 IM	382	if (cpu->hotpluggable)
1c4e2d70 IM	383	cpu->dev.groups = hotplugable_cpu_attr_groups;
8a25a2fd	384	error = device_register(&cpu->dev);
3aaba245 AY	385	if (error) {
3aaba245 AY	386	put_device(&cpu->dev);
59fffa34	387	return error;
3aaba245	388	}
51be5606	389
59fffa34 AS	390	per_cpu(cpu_sys_devices, num) = &cpu->dev;
59fffa34 AS	391	register_cpu_under_node(num, cpu_to_node(num));
0759e80b RW	392	dev_pm_qos_expose_latency_limit(&cpu->dev,
0759e80b RW	393	PM_QOS_RESUME_LATENCY_NO_CONSTRAINT);
59fffa34 AS	394
59fffa34 AS	395	return 0;
1da177e4 LT	396	}
1da177e4 LT	397
8a25a2fd	398	struct device *get_cpu_device(unsigned cpu)
ad74557a	399	{
e37d05da MT	400	if (cpu < nr_cpu_ids && cpu_possible(cpu))
e37d05da MT	401	return per_cpu(cpu_sys_devices, cpu);
ad74557a AR	402	else
	403	return NULL;
	404	}
8a25a2fd KS	405	EXPORT_SYMBOL_GPL(get_cpu_device);
8a25a2fd KS	406
3d52943b SH	407	static void device_create_release(struct device *dev)
	408	{
	409	kfree(dev);
	410	}
	411
fa548d79	412	__printf(4, 0)
3d52943b SH	413	static struct device *
	414	__cpu_device_create(struct device parent, void drvdata,
	415	const struct attribute_group **groups,
	416	const char *fmt, va_list args)
	417	{
	418	struct device *dev = NULL;
	419	int retval = -ENODEV;
	420
	421	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
	422	if (!dev) {
	423	retval = -ENOMEM;
	424	goto error;
	425	}
	426
	427	device_initialize(dev);
	428	dev->parent = parent;
	429	dev->groups = groups;
	430	dev->release = device_create_release;
85945c28	431	device_set_pm_not_required(dev);
3d52943b SH	432	dev_set_drvdata(dev, drvdata);
	433
	434	retval = kobject_set_name_vargs(&dev->kobj, fmt, args);
	435	if (retval)
	436	goto error;
	437
	438	retval = device_add(dev);
	439	if (retval)
	440	goto error;
	441
	442	return dev;
	443
	444	error:
	445	put_device(dev);
	446	return ERR_PTR(retval);
	447	}
	448
	449	struct device cpu_device_create(struct device parent, void *drvdata,
	450	const struct attribute_group **groups,
	451	const char *fmt, ...)
	452	{
	453	va_list vargs;
	454	struct device *dev;
	455
	456	va_start(vargs, fmt);
	457	dev = __cpu_device_create(parent, drvdata, groups, fmt, vargs);
	458	va_end(vargs);
	459	return dev;
	460	}
	461	EXPORT_SYMBOL_GPL(cpu_device_create);
	462
2b9c1f03	463	#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
67bad2fd	464	static DEVICE_ATTR(modalias, 0444, print_cpu_modalias, NULL);
fad12ac8 TR	465	#endif
fad12ac8 TR	466
8a25a2fd KS	467	static struct attribute *cpu_root_attrs[] = {
	468	#ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
	469	&dev_attr_probe.attr,
	470	&dev_attr_release.attr,
	471	#endif
	472	&cpu_attrs[0].attr.attr,
	473	&cpu_attrs[1].attr.attr,
	474	&cpu_attrs[2].attr.attr,
	475	&dev_attr_kernel_max.attr,
	476	&dev_attr_offline.attr,
59f30abe	477	&dev_attr_isolated.attr,
6570a9a1 RR	478	#ifdef CONFIG_NO_HZ_FULL
	479	&dev_attr_nohz_full.attr,
	480	#endif
2b9c1f03	481	#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
fad12ac8 TR	482	&dev_attr_modalias.attr,
fad12ac8 TR	483	#endif
8a25a2fd KS	484	NULL
	485	};
	486
	487	static struct attribute_group cpu_root_attr_group = {
	488	.attrs = cpu_root_attrs,
	489	};
	490
	491	static const struct attribute_group *cpu_root_attr_groups[] = {
	492	&cpu_root_attr_group,
	493	NULL,
	494	};
1da177e4	495
2987557f JT	496	bool cpu_is_hotpluggable(unsigned cpu)
2987557f JT	497	{
7affca35 LT	498	struct device *dev = get_cpu_device(cpu);
7affca35 LT	499	return dev && container_of(dev, struct cpu, dev)->hotpluggable;
2987557f JT	500	}
	501	EXPORT_SYMBOL_GPL(cpu_is_hotpluggable);
	502
9f13a1fd BH	503	#ifdef CONFIG_GENERIC_CPU_DEVICES
	504	static DEFINE_PER_CPU(struct cpu, cpu_devices);
	505	#endif
	506
	507	static void __init cpu_dev_register_generic(void)
	508	{
	509	#ifdef CONFIG_GENERIC_CPU_DEVICES
	510	int i;
	511
	512	for_each_possible_cpu(i) {
	513	if (register_cpu(&per_cpu(cpu_devices, i), i))
	514	panic("Failed to register CPU device");
	515	}
	516	#endif
	517	}
	518
87590ce6 TG	519	#ifdef CONFIG_GENERIC_CPU_VULNERABILITIES
	520
	521	ssize_t __weak cpu_show_meltdown(struct device *dev,
	522	struct device_attribute attr, char buf)
	523	{
	524	return sprintf(buf, "Not affected\n");
	525	}
	526
	527	ssize_t __weak cpu_show_spectre_v1(struct device *dev,
	528	struct device_attribute attr, char buf)
	529	{
	530	return sprintf(buf, "Not affected\n");
	531	}
	532
	533	ssize_t __weak cpu_show_spectre_v2(struct device *dev,
	534	struct device_attribute attr, char buf)
	535	{
	536	return sprintf(buf, "Not affected\n");
	537	}
	538
c456442c KRW	539	ssize_t __weak cpu_show_spec_store_bypass(struct device *dev,
	540	struct device_attribute attr, char buf)
	541	{
	542	return sprintf(buf, "Not affected\n");
	543	}
	544
17dbca11 AK	545	ssize_t __weak cpu_show_l1tf(struct device *dev,
	546	struct device_attribute attr, char buf)
	547	{
	548	return sprintf(buf, "Not affected\n");
	549	}
	550
8a4b06d3 TG	551	ssize_t __weak cpu_show_mds(struct device *dev,
	552	struct device_attribute attr, char buf)
	553	{
	554	return sprintf(buf, "Not affected\n");
	555	}
	556
9adb8ec1 PG	557	ssize_t __weak cpu_show_tsx_async_abort(struct device *dev,
	558	struct device_attribute *attr,
	559	char *buf)
	560	{
	561	return sprintf(buf, "Not affected\n");
	562	}
	563
cf423e32 VT	564	ssize_t __weak cpu_show_itlb_multihit(struct device *dev,
	565	struct device_attribute attr, char buf)
	566	{
	567	return sprintf(buf, "Not affected\n");
	568	}
	569
87590ce6 TG	570	static DEVICE_ATTR(meltdown, 0444, cpu_show_meltdown, NULL);
	571	static DEVICE_ATTR(spectre_v1, 0444, cpu_show_spectre_v1, NULL);
	572	static DEVICE_ATTR(spectre_v2, 0444, cpu_show_spectre_v2, NULL);
c456442c	573	static DEVICE_ATTR(spec_store_bypass, 0444, cpu_show_spec_store_bypass, NULL);
17dbca11	574	static DEVICE_ATTR(l1tf, 0444, cpu_show_l1tf, NULL);
8a4b06d3	575	static DEVICE_ATTR(mds, 0444, cpu_show_mds, NULL);
9adb8ec1	576	static DEVICE_ATTR(tsx_async_abort, 0444, cpu_show_tsx_async_abort, NULL);
cf423e32	577	static DEVICE_ATTR(itlb_multihit, 0444, cpu_show_itlb_multihit, NULL);
87590ce6 TG	578
	579	static struct attribute *cpu_root_vulnerabilities_attrs[] = {
	580	&dev_attr_meltdown.attr,
	581	&dev_attr_spectre_v1.attr,
	582	&dev_attr_spectre_v2.attr,
c456442c	583	&dev_attr_spec_store_bypass.attr,
17dbca11	584	&dev_attr_l1tf.attr,
8a4b06d3	585	&dev_attr_mds.attr,
9adb8ec1	586	&dev_attr_tsx_async_abort.attr,
cf423e32	587	&dev_attr_itlb_multihit.attr,
87590ce6 TG	588	NULL
	589	};
	590
	591	static const struct attribute_group cpu_root_vulnerabilities_group = {
	592	.name = "vulnerabilities",
	593	.attrs = cpu_root_vulnerabilities_attrs,
	594	};
	595
	596	static void __init cpu_register_vulnerabilities(void)
	597	{
	598	if (sysfs_create_group(&cpu_subsys.dev_root->kobj,
	599	&cpu_root_vulnerabilities_group))
	600	pr_err("Unable to register CPU vulnerabilities\n");
	601	}
	602
	603	#else
	604	static inline void cpu_register_vulnerabilities(void) { }
	605	#endif
	606
024f7846	607	void __init cpu_dev_init(void)
1da177e4	608	{
024f7846 BH	609	if (subsys_system_register(&cpu_subsys, cpu_root_attr_groups))
024f7846 BH	610	panic("Failed to register CPU subsystem");
8a25a2fd	611
9f13a1fd	612	cpu_dev_register_generic();
87590ce6	613	cpu_register_vulnerabilities();
1da177e4	614	}