[mirror_ubuntu-bionic-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 <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)
		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);
}

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

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

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

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

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

	return dev;

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

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

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

#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
static DEVICE_ATTR(modalias, 0444, print_cpu_modalias, NULL);
#endif

static struct attribute *cpu_root_attrs[] = {
#ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
	&dev_attr_probe.attr,
	&dev_attr_release.attr,
#endif
	&cpu_attrs[0].attr.attr,
	&cpu_attrs[1].attr.attr,
	&cpu_attrs[2].attr.attr,
	&dev_attr_kernel_max.attr,
	&dev_attr_offline.attr,
	&dev_attr_isolated.attr,
#ifdef CONFIG_NO_HZ_FULL
	&dev_attr_nohz_full.attr,
#endif
#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
	&dev_attr_modalias.attr,
#endif
	NULL
};

static struct attribute_group cpu_root_attr_group = {
	.attrs = cpu_root_attrs,
};

static const struct attribute_group *cpu_root_attr_groups[] = {
	&cpu_root_attr_group,
	NULL,
};

bool cpu_is_hotpluggable(unsigned cpu)
{
	struct device *dev = get_cpu_device(cpu);
	return dev && container_of(dev, struct cpu, dev)->hotpluggable;
}
EXPORT_SYMBOL_GPL(cpu_is_hotpluggable);

#ifdef CONFIG_GENERIC_CPU_DEVICES
static DEFINE_PER_CPU(struct cpu, cpu_devices);
#endif

static void __init cpu_dev_register_generic(void)
{
#ifdef CONFIG_GENERIC_CPU_DEVICES
	int i;

	for_each_possible_cpu(i) {
		if (register_cpu(&per_cpu(cpu_devices, i), i))
			panic("Failed to register CPU device");
	}
#endif
}

#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");
}

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 struct attribute *cpu_root_vulnerabilities_attrs[] = {
	&dev_attr_meltdown.attr,
	&dev_attr_spectre_v1.attr,
	&dev_attr_spectre_v2.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
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>
6570a9a1	19	#include <linux/tick.h>
37efa4b4	20	#include <linux/pm_qos.h>
edb93821	21	#include <linux/sched/isolation.h>
1da177e4	22
a1bdc7aa	23	#include "base.h"
1da177e4	24
8a25a2fd	25	static DEFINE_PER_CPU(struct device *, cpu_sys_devices);
ad74557a	26
ac212b69 RW	27	static int cpu_subsys_match(struct device dev, struct device_driver drv)
	28	{
	29	/* ACPI style match is the only one that may succeed. */
	30	if (acpi_driver_match_device(dev, drv))
	31	return 1;
	32
	33	return 0;
	34	}
	35
1da177e4	36	#ifdef CONFIG_HOTPLUG_CPU
34640468 YI	37	static void change_cpu_under_node(struct cpu *cpu,
	38	unsigned int from_nid, unsigned int to_nid)
	39	{
	40	int cpuid = cpu->dev.id;
	41	unregister_cpu_under_node(cpuid, from_nid);
	42	register_cpu_under_node(cpuid, to_nid);
	43	cpu->node_id = to_nid;
	44	}
	45
eda5867b	46	static int cpu_subsys_online(struct device *dev)
1da177e4	47	{
8a25a2fd	48	struct cpu *cpu = container_of(dev, struct cpu, dev);
0902a904 RW	49	int cpuid = dev->id;
0902a904 RW	50	int from_nid, to_nid;
6dedcca6	51	int ret;
1da177e4	52
0902a904	53	from_nid = cpu_to_node(cpuid);
c7991b0b	54	if (from_nid == NUMA_NO_NODE)
6dedcca6	55	return -ENODEV;
c7991b0b	56
0902a904 RW	57	ret = cpu_up(cpuid);
	58	/*
	59	* When hot adding memory to memoryless node and enabling a cpu
	60	* on the node, node number of the cpu may internally change.
	61	*/
	62	to_nid = cpu_to_node(cpuid);
	63	if (from_nid != to_nid)
	64	change_cpu_under_node(cpu, from_nid, to_nid);
1da177e4	65
0902a904	66	return ret;
1da177e4 LT	67	}
1da177e4 LT	68
0902a904	69	static int cpu_subsys_offline(struct device *dev)
1da177e4	70	{
6dedcca6	71	return cpu_down(dev->id);
1da177e4	72	}
1c4e2d70	73
76b67ed9	74	void unregister_cpu(struct cpu *cpu)
1da177e4	75	{
8a25a2fd	76	int logical_cpu = cpu->dev.id;
1da177e4	77
76b67ed9 KH	78	unregister_cpu_under_node(logical_cpu, cpu_to_node(logical_cpu));
76b67ed9 KH	79
8a25a2fd	80	device_unregister(&cpu->dev);
e37d05da	81	per_cpu(cpu_sys_devices, logical_cpu) = NULL;
1da177e4 LT	82	return;
1da177e4 LT	83	}
12633e80 NF	84
12633e80 NF	85	#ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
8a25a2fd KS	86	static ssize_t cpu_probe_store(struct device *dev,
8a25a2fd KS	87	struct device_attribute *attr,
67fc233f	88	const char *buf,
12633e80 NF	89	size_t count)
12633e80 NF	90	{
574b851e TK	91	ssize_t cnt;
	92	int ret;
	93
	94	ret = lock_device_hotplug_sysfs();
	95	if (ret)
	96	return ret;
	97
	98	cnt = arch_cpu_probe(buf, count);
	99
	100	unlock_device_hotplug();
	101	return cnt;
12633e80 NF	102	}
12633e80 NF	103
8a25a2fd KS	104	static ssize_t cpu_release_store(struct device *dev,
8a25a2fd KS	105	struct device_attribute *attr,
67fc233f	106	const char *buf,
12633e80 NF	107	size_t count)
12633e80 NF	108	{
574b851e TK	109	ssize_t cnt;
	110	int ret;
	111
	112	ret = lock_device_hotplug_sysfs();
	113	if (ret)
	114	return ret;
	115
	116	cnt = arch_cpu_release(buf, count);
	117
	118	unlock_device_hotplug();
	119	return cnt;
12633e80 NF	120	}
12633e80 NF	121
8a25a2fd KS	122	static DEVICE_ATTR(probe, S_IWUSR, NULL, cpu_probe_store);
8a25a2fd KS	123	static DEVICE_ATTR(release, S_IWUSR, NULL, cpu_release_store);
12633e80	124	#endif /* CONFIG_ARCH_CPU_PROBE_RELEASE */
1da177e4 LT	125	#endif /* CONFIG_HOTPLUG_CPU */
1da177e4 LT	126
0902a904 RW	127	struct bus_type cpu_subsys = {
	128	.name = "cpu",
	129	.dev_name = "cpu",
ac212b69	130	.match = cpu_subsys_match,
0902a904 RW	131	#ifdef CONFIG_HOTPLUG_CPU
	132	.online = cpu_subsys_online,
	133	.offline = cpu_subsys_offline,
	134	#endif
	135	};
	136	EXPORT_SYMBOL_GPL(cpu_subsys);
	137
51be5606 VG	138	#ifdef CONFIG_KEXEC
	139	#include <linux/kexec.h>
	140
8a25a2fd	141	static ssize_t show_crash_notes(struct device dev, struct device_attribute attr,
4a0b2b4d	142	char *buf)
51be5606	143	{
8a25a2fd	144	struct cpu *cpu = container_of(dev, struct cpu, dev);
51be5606 VG	145	ssize_t rc;
	146	unsigned long long addr;
	147	int cpunum;
	148
8a25a2fd	149	cpunum = cpu->dev.id;
51be5606 VG	150
	151	/*
	152	* Might be reading other cpu's data based on which cpu read thread
	153	* has been scheduled. But cpu data (memory) is allocated once during
	154	* boot up and this data does not change there after. Hence this
	155	* operation should be safe. No locking required.
	156	*/
3b034b0d	157	addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpunum));
51be5606	158	rc = sprintf(buf, "%Lx\n", addr);
51be5606 VG	159	return rc;
51be5606 VG	160	}
8a25a2fd	161	static DEVICE_ATTR(crash_notes, 0400, show_crash_notes, NULL);
eca4549f ZY	162
	163	static ssize_t show_crash_notes_size(struct device *dev,
	164	struct device_attribute *attr,
	165	char *buf)
	166	{
	167	ssize_t rc;
	168
bcfb87fb	169	rc = sprintf(buf, "%zu\n", sizeof(note_buf_t));
eca4549f ZY	170	return rc;
	171	}
	172	static DEVICE_ATTR(crash_notes_size, 0400, show_crash_notes_size, NULL);
c055da9f IM	173
	174	static struct attribute *crash_note_cpu_attrs[] = {
	175	&dev_attr_crash_notes.attr,
	176	&dev_attr_crash_notes_size.attr,
	177	NULL
	178	};
	179
	180	static struct attribute_group crash_note_cpu_attr_group = {
	181	.attrs = crash_note_cpu_attrs,
	182	};
	183	#endif
	184
	185	static const struct attribute_group *common_cpu_attr_groups[] = {
	186	#ifdef CONFIG_KEXEC
	187	&crash_note_cpu_attr_group,
51be5606	188	#endif
c055da9f IM	189	NULL
c055da9f IM	190	};
51be5606	191
1c4e2d70 IM	192	static const struct attribute_group *hotplugable_cpu_attr_groups[] = {
	193	#ifdef CONFIG_KEXEC
	194	&crash_note_cpu_attr_group,
1c4e2d70 IM	195	#endif
	196	NULL
	197	};
	198
9d1fe323 MT	199	/*
	200	* Print cpu online, possible, present, and system maps
	201	*/
265d2e2e AK	202
265d2e2e AK	203	struct cpu_attr {
8a25a2fd	204	struct device_attribute attr;
848e2391	205	const struct cpumask *const map;
265d2e2e AK	206	};
265d2e2e AK	207
8a25a2fd KS	208	static ssize_t show_cpus_attr(struct device *dev,
8a25a2fd KS	209	struct device_attribute *attr,
265d2e2e	210	char *buf)
9d1fe323	211	{
265d2e2e	212	struct cpu_attr *ca = container_of(attr, struct cpu_attr, attr);
9d1fe323	213
848e2391	214	return cpumap_print_to_pagebuf(true, buf, ca->map);
9d1fe323 MT	215	}
9d1fe323 MT	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	221	static struct cpu_attr cpu_attrs[] = {
848e2391 RV	222	_CPU_ATTR(online, &__cpu_online_mask),
	223	_CPU_ATTR(possible, &__cpu_possible_mask),
	224	_CPU_ATTR(present, &__cpu_present_mask),
265d2e2e	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);
f799b1a7	251	n = scnprintf(buf, len, "%*pbl", cpumask_pr_args(offline));
e057d7ae MT	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)
9b130ad5	260	n += snprintf(&buf[n], len - n, "%u", nr_cpu_ids);
e057d7ae	261	else
9b130ad5	262	n += snprintf(&buf[n], len - n, "%u-%d",
e057d7ae MT	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
59f30abe RR	271	static ssize_t print_cpus_isolated(struct device *dev,
	272	struct device_attribute attr, char buf)
	273	{
	274	int n = 0, len = PAGE_SIZE-2;
edb93821	275	cpumask_var_t isolated;
59f30abe	276
edb93821 FW	277	if (!alloc_cpumask_var(&isolated, GFP_KERNEL))
	278	return -ENOMEM;
	279
	280	cpumask_andnot(isolated, cpu_possible_mask,
	281	housekeeping_cpumask(HK_FLAG_DOMAIN));
	282	n = scnprintf(buf, len, "%*pbl\n", cpumask_pr_args(isolated));
	283
	284	free_cpumask_var(isolated);
59f30abe RR	285
	286	return n;
	287	}
	288	static DEVICE_ATTR(isolated, 0444, print_cpus_isolated, NULL);
	289
6570a9a1 RR	290	#ifdef CONFIG_NO_HZ_FULL
	291	static ssize_t print_cpus_nohz_full(struct device *dev,
	292	struct device_attribute attr, char buf)
	293	{
	294	int n = 0, len = PAGE_SIZE-2;
	295
	296	n = scnprintf(buf, len, "%*pbl\n", cpumask_pr_args(tick_nohz_full_mask));
	297
	298	return n;
	299	}
	300	static DEVICE_ATTR(nohz_full, 0444, print_cpus_nohz_full, NULL);
	301	#endif
	302
2885e25c GKH	303	static void cpu_device_release(struct device *dev)
	304	{
	305	/*
	306	* This is an empty function to prevent the driver core from spitting a
	307	* warning at us. Yes, I know this is directly opposite of what the
	308	* documentation for the driver core and kobjects say, and the author
	309	* of this code has already been publically ridiculed for doing
	310	* something as foolish as this. However, at this point in time, it is
	311	* the only way to handle the issue of statically allocated cpu
	312	* devices. The different architectures will have their cpu device
	313	* code reworked to properly handle this in the near future, so this
	314	* function will then be changed to correctly free up the memory held
	315	* by the cpu device.
	316	*
	317	* Never copy this way of doing things, or you too will be made fun of
30a4840a	318	* on the linux-kernel list, you have been warned.
2885e25c GKH	319	*/
	320	}
	321
67bad2fd AB	322	#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
	323	static ssize_t print_cpu_modalias(struct device *dev,
	324	struct device_attribute *attr,
	325	char *buf)
	326	{
	327	ssize_t n;
	328	u32 i;
	329
	330	n = sprintf(buf, "cpu:type:" CPU_FEATURE_TYPEFMT ":feature:",
	331	CPU_FEATURE_TYPEVAL);
	332
	333	for (i = 0; i < MAX_CPU_FEATURES; i++)
	334	if (cpu_have_feature(i)) {
	335	if (PAGE_SIZE < n + sizeof(",XXXX\n")) {
	336	WARN(1, "CPU features overflow page\n");
	337	break;
	338	}
	339	n += sprintf(&buf[n], ",%04X", i);
	340	}
	341	buf[n++] = '\n';
	342	return n;
	343	}
67bad2fd AB	344
	345	static int cpu_uevent(struct device dev, struct kobj_uevent_env env)
	346	{
	347	char *buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
	348	if (buf) {
	349	print_cpu_modalias(NULL, NULL, buf);
	350	add_uevent_var(env, "MODALIAS=%s", buf);
	351	kfree(buf);
	352	}
	353	return 0;
	354	}
	355	#endif
	356
1da177e4	357	/*
405ae7d3	358	* register_cpu - Setup a sysfs device for a CPU.
72486f1f SS	359	* @cpu - cpu->hotpluggable field set to 1 will generate a control file in
72486f1f SS	360	* sysfs for this CPU.
1da177e4 LT	361	* @num - CPU number to use when creating the device.
	362	*
	363	* Initialize and register the CPU device.
	364	*/
a83048eb	365	int register_cpu(struct cpu *cpu, int num)
1da177e4 LT	366	{
1da177e4 LT	367	int error;
76b67ed9	368
8a25a2fd	369	cpu->node_id = cpu_to_node(num);
29bb5d4f	370	memset(&cpu->dev, 0x00, sizeof(struct device));
8a25a2fd KS	371	cpu->dev.id = num;
8a25a2fd KS	372	cpu->dev.bus = &cpu_subsys;
2885e25c	373	cpu->dev.release = cpu_device_release;
0902a904	374	cpu->dev.offline_disabled = !cpu->hotpluggable;
1001b4d4	375	cpu->dev.offline = !cpu_online(num);
f86e4718	376	cpu->dev.of_node = of_get_cpu_node(num, NULL);
2b9c1f03	377	#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
67bad2fd	378	cpu->dev.bus->uevent = cpu_uevent;
fad12ac8	379	#endif
c055da9f	380	cpu->dev.groups = common_cpu_attr_groups;
1c4e2d70 IM	381	if (cpu->hotpluggable)
1c4e2d70 IM	382	cpu->dev.groups = hotplugable_cpu_attr_groups;
8a25a2fd	383	error = device_register(&cpu->dev);
59fffa34 AS	384	if (error)
59fffa34 AS	385	return error;
51be5606	386
59fffa34 AS	387	per_cpu(cpu_sys_devices, num) = &cpu->dev;
59fffa34 AS	388	register_cpu_under_node(num, cpu_to_node(num));
0759e80b RW	389	dev_pm_qos_expose_latency_limit(&cpu->dev,
0759e80b RW	390	PM_QOS_RESUME_LATENCY_NO_CONSTRAINT);
59fffa34 AS	391
59fffa34 AS	392	return 0;
1da177e4 LT	393	}
1da177e4 LT	394
8a25a2fd	395	struct device *get_cpu_device(unsigned cpu)
ad74557a	396	{
e37d05da MT	397	if (cpu < nr_cpu_ids && cpu_possible(cpu))
e37d05da MT	398	return per_cpu(cpu_sys_devices, cpu);
ad74557a AR	399	else
	400	return NULL;
	401	}
8a25a2fd KS	402	EXPORT_SYMBOL_GPL(get_cpu_device);
8a25a2fd KS	403
3d52943b SH	404	static void device_create_release(struct device *dev)
	405	{
	406	kfree(dev);
	407	}
	408
	409	static struct device *
	410	__cpu_device_create(struct device parent, void drvdata,
	411	const struct attribute_group **groups,
	412	const char *fmt, va_list args)
	413	{
	414	struct device *dev = NULL;
	415	int retval = -ENODEV;
	416
	417	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
	418	if (!dev) {
	419	retval = -ENOMEM;
	420	goto error;
	421	}
	422
	423	device_initialize(dev);
	424	dev->parent = parent;
	425	dev->groups = groups;
	426	dev->release = device_create_release;
	427	dev_set_drvdata(dev, drvdata);
	428
	429	retval = kobject_set_name_vargs(&dev->kobj, fmt, args);
	430	if (retval)
	431	goto error;
	432
	433	retval = device_add(dev);
	434	if (retval)
	435	goto error;
	436
	437	return dev;
	438
	439	error:
	440	put_device(dev);
	441	return ERR_PTR(retval);
	442	}
	443
	444	struct device cpu_device_create(struct device parent, void *drvdata,
	445	const struct attribute_group **groups,
	446	const char *fmt, ...)
	447	{
	448	va_list vargs;
	449	struct device *dev;
	450
	451	va_start(vargs, fmt);
	452	dev = __cpu_device_create(parent, drvdata, groups, fmt, vargs);
	453	va_end(vargs);
	454	return dev;
	455	}
	456	EXPORT_SYMBOL_GPL(cpu_device_create);
	457
2b9c1f03	458	#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
67bad2fd	459	static DEVICE_ATTR(modalias, 0444, print_cpu_modalias, NULL);
fad12ac8 TR	460	#endif
fad12ac8 TR	461
8a25a2fd KS	462	static struct attribute *cpu_root_attrs[] = {
	463	#ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
	464	&dev_attr_probe.attr,
	465	&dev_attr_release.attr,
	466	#endif
	467	&cpu_attrs[0].attr.attr,
	468	&cpu_attrs[1].attr.attr,
	469	&cpu_attrs[2].attr.attr,
	470	&dev_attr_kernel_max.attr,
	471	&dev_attr_offline.attr,
59f30abe	472	&dev_attr_isolated.attr,
6570a9a1 RR	473	#ifdef CONFIG_NO_HZ_FULL
	474	&dev_attr_nohz_full.attr,
	475	#endif
2b9c1f03	476	#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
fad12ac8 TR	477	&dev_attr_modalias.attr,
fad12ac8 TR	478	#endif
8a25a2fd KS	479	NULL
	480	};
	481
	482	static struct attribute_group cpu_root_attr_group = {
	483	.attrs = cpu_root_attrs,
	484	};
	485
	486	static const struct attribute_group *cpu_root_attr_groups[] = {
	487	&cpu_root_attr_group,
	488	NULL,
	489	};
1da177e4	490
2987557f JT	491	bool cpu_is_hotpluggable(unsigned cpu)
2987557f JT	492	{
7affca35 LT	493	struct device *dev = get_cpu_device(cpu);
7affca35 LT	494	return dev && container_of(dev, struct cpu, dev)->hotpluggable;
2987557f JT	495	}
	496	EXPORT_SYMBOL_GPL(cpu_is_hotpluggable);
	497
9f13a1fd BH	498	#ifdef CONFIG_GENERIC_CPU_DEVICES
	499	static DEFINE_PER_CPU(struct cpu, cpu_devices);
	500	#endif
	501
	502	static void __init cpu_dev_register_generic(void)
	503	{
	504	#ifdef CONFIG_GENERIC_CPU_DEVICES
	505	int i;
	506
	507	for_each_possible_cpu(i) {
	508	if (register_cpu(&per_cpu(cpu_devices, i), i))
	509	panic("Failed to register CPU device");
	510	}
	511	#endif
	512	}
	513
87590ce6 TG	514	#ifdef CONFIG_GENERIC_CPU_VULNERABILITIES
	515
	516	ssize_t __weak cpu_show_meltdown(struct device *dev,
	517	struct device_attribute attr, char buf)
	518	{
	519	return sprintf(buf, "Not affected\n");
	520	}
	521
	522	ssize_t __weak cpu_show_spectre_v1(struct device *dev,
	523	struct device_attribute attr, char buf)
	524	{
	525	return sprintf(buf, "Not affected\n");
	526	}
	527
	528	ssize_t __weak cpu_show_spectre_v2(struct device *dev,
	529	struct device_attribute attr, char buf)
	530	{
	531	return sprintf(buf, "Not affected\n");
	532	}
	533
	534	static DEVICE_ATTR(meltdown, 0444, cpu_show_meltdown, NULL);
	535	static DEVICE_ATTR(spectre_v1, 0444, cpu_show_spectre_v1, NULL);
	536	static DEVICE_ATTR(spectre_v2, 0444, cpu_show_spectre_v2, NULL);
	537
	538	static struct attribute *cpu_root_vulnerabilities_attrs[] = {
	539	&dev_attr_meltdown.attr,
	540	&dev_attr_spectre_v1.attr,
	541	&dev_attr_spectre_v2.attr,
	542	NULL
	543	};
	544
	545	static const struct attribute_group cpu_root_vulnerabilities_group = {
	546	.name = "vulnerabilities",
	547	.attrs = cpu_root_vulnerabilities_attrs,
	548	};
	549
	550	static void __init cpu_register_vulnerabilities(void)
	551	{
	552	if (sysfs_create_group(&cpu_subsys.dev_root->kobj,
	553	&cpu_root_vulnerabilities_group))
	554	pr_err("Unable to register CPU vulnerabilities\n");
	555	}
	556
	557	#else
	558	static inline void cpu_register_vulnerabilities(void) { }
	559	#endif
	560
024f7846	561	void __init cpu_dev_init(void)
1da177e4	562	{
024f7846 BH	563	if (subsys_system_register(&cpu_subsys, cpu_root_attr_groups))
024f7846 BH	564	panic("Failed to register CPU subsystem");
8a25a2fd	565
9f13a1fd	566	cpu_dev_register_generic();
87590ce6	567	cpu_register_vulnerabilities();
1da177e4	568	}