[linux.git] / kernel / ksysfs.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * kernel/ksysfs.c - sysfs attributes in /sys/kernel, which
 * 		     are not related to any other subsystem
 *
 * Copyright (C) 2004 Kay Sievers <[email protected]>
 */

#include <linux/kobject.h>
#include <linux/string.h>
#include <linux/sysfs.h>
#include <linux/export.h>
#include <linux/init.h>
#include <linux/kexec.h>
#include <linux/profile.h>
#include <linux/stat.h>
#include <linux/sched.h>
#include <linux/capability.h>
#include <linux/compiler.h>

#include <linux/rcupdate.h>	/* rcu_expedited and rcu_normal */

#define KERNEL_ATTR_RO(_name) \
static struct kobj_attribute _name##_attr = __ATTR_RO(_name)

#define KERNEL_ATTR_RW(_name) \
static struct kobj_attribute _name##_attr = \
	__ATTR(_name, 0644, _name##_show, _name##_store)

/* current uevent sequence number */
static ssize_t uevent_seqnum_show(struct kobject *kobj,
				  struct kobj_attribute *attr, char *buf)
{
	return sprintf(buf, "%llu\n", (unsigned long long)uevent_seqnum);
}
KERNEL_ATTR_RO(uevent_seqnum);

#ifdef CONFIG_UEVENT_HELPER
/* uevent helper program, used during early boot */
static ssize_t uevent_helper_show(struct kobject *kobj,
				  struct kobj_attribute *attr, char *buf)
{
	return sprintf(buf, "%s\n", uevent_helper);
}
static ssize_t uevent_helper_store(struct kobject *kobj,
				   struct kobj_attribute *attr,
				   const char *buf, size_t count)
{
	if (count+1 > UEVENT_HELPER_PATH_LEN)
		return -ENOENT;
	memcpy(uevent_helper, buf, count);
	uevent_helper[count] = '\0';
	if (count && uevent_helper[count-1] == '\n')
		uevent_helper[count-1] = '\0';
	return count;
}
KERNEL_ATTR_RW(uevent_helper);
#endif

#ifdef CONFIG_PROFILING
static ssize_t profiling_show(struct kobject *kobj,
				  struct kobj_attribute *attr, char *buf)
{
	return sprintf(buf, "%d\n", prof_on);
}
static ssize_t profiling_store(struct kobject *kobj,
				   struct kobj_attribute *attr,
				   const char *buf, size_t count)
{
	int ret;

	if (prof_on)
		return -EEXIST;
	/*
	 * This eventually calls into get_option() which
	 * has a ton of callers and is not const.  It is
	 * easiest to cast it away here.
	 */
	profile_setup((char *)buf);
	ret = profile_init();
	if (ret)
		return ret;
	ret = create_proc_profile();
	if (ret)
		return ret;
	return count;
}
KERNEL_ATTR_RW(profiling);
#endif

#ifdef CONFIG_KEXEC_CORE
static ssize_t kexec_loaded_show(struct kobject *kobj,
				 struct kobj_attribute *attr, char *buf)
{
	return sprintf(buf, "%d\n", !!kexec_image);
}
KERNEL_ATTR_RO(kexec_loaded);

static ssize_t kexec_crash_loaded_show(struct kobject *kobj,
				       struct kobj_attribute *attr, char *buf)
{
	return sprintf(buf, "%d\n", kexec_crash_loaded());
}
KERNEL_ATTR_RO(kexec_crash_loaded);

static ssize_t kexec_crash_size_show(struct kobject *kobj,
				       struct kobj_attribute *attr, char *buf)
{
	return sprintf(buf, "%zu\n", crash_get_memory_size());
}
static ssize_t kexec_crash_size_store(struct kobject *kobj,
				   struct kobj_attribute *attr,
				   const char *buf, size_t count)
{
	unsigned long cnt;
	int ret;

	if (kstrtoul(buf, 0, &cnt))
		return -EINVAL;

	ret = crash_shrink_memory(cnt);
	return ret < 0 ? ret : count;
}
KERNEL_ATTR_RW(kexec_crash_size);

#endif /* CONFIG_KEXEC_CORE */

#ifdef CONFIG_CRASH_CORE

static ssize_t vmcoreinfo_show(struct kobject *kobj,
			       struct kobj_attribute *attr, char *buf)
{
	phys_addr_t vmcore_base = paddr_vmcoreinfo_note();
	return sprintf(buf, "%pa %x\n", &vmcore_base,
			(unsigned int)VMCOREINFO_NOTE_SIZE);
}
KERNEL_ATTR_RO(vmcoreinfo);

#endif /* CONFIG_CRASH_CORE */

/* whether file capabilities are enabled */
static ssize_t fscaps_show(struct kobject *kobj,
				  struct kobj_attribute *attr, char *buf)
{
	return sprintf(buf, "%d\n", file_caps_enabled);
}
KERNEL_ATTR_RO(fscaps);

#ifndef CONFIG_TINY_RCU
int rcu_expedited;
static ssize_t rcu_expedited_show(struct kobject *kobj,
				  struct kobj_attribute *attr, char *buf)
{
	return sprintf(buf, "%d\n", READ_ONCE(rcu_expedited));
}
static ssize_t rcu_expedited_store(struct kobject *kobj,
				   struct kobj_attribute *attr,
				   const char *buf, size_t count)
{
	if (kstrtoint(buf, 0, &rcu_expedited))
		return -EINVAL;

	return count;
}
KERNEL_ATTR_RW(rcu_expedited);

int rcu_normal;
static ssize_t rcu_normal_show(struct kobject *kobj,
			       struct kobj_attribute *attr, char *buf)
{
	return sprintf(buf, "%d\n", READ_ONCE(rcu_normal));
}
static ssize_t rcu_normal_store(struct kobject *kobj,
				struct kobj_attribute *attr,
				const char *buf, size_t count)
{
	if (kstrtoint(buf, 0, &rcu_normal))
		return -EINVAL;

	return count;
}
KERNEL_ATTR_RW(rcu_normal);
#endif /* #ifndef CONFIG_TINY_RCU */

/*
 * Make /sys/kernel/notes give the raw contents of our kernel .notes section.
 */
extern const void __start_notes __weak;
extern const void __stop_notes __weak;
#define	notes_size (&__stop_notes - &__start_notes)

static ssize_t notes_read(struct file *filp, struct kobject *kobj,
			  struct bin_attribute *bin_attr,
			  char *buf, loff_t off, size_t count)
{
	memcpy(buf, &__start_notes + off, count);
	return count;
}

static struct bin_attribute notes_attr __ro_after_init  = {
	.attr = {
		.name = "notes",
		.mode = S_IRUGO,
	},
	.read = &notes_read,
};

struct kobject *kernel_kobj;
EXPORT_SYMBOL_GPL(kernel_kobj);

static struct attribute * kernel_attrs[] = {
	&fscaps_attr.attr,
	&uevent_seqnum_attr.attr,
#ifdef CONFIG_UEVENT_HELPER
	&uevent_helper_attr.attr,
#endif
#ifdef CONFIG_PROFILING
	&profiling_attr.attr,
#endif
#ifdef CONFIG_KEXEC_CORE
	&kexec_loaded_attr.attr,
	&kexec_crash_loaded_attr.attr,
	&kexec_crash_size_attr.attr,
#endif
#ifdef CONFIG_CRASH_CORE
	&vmcoreinfo_attr.attr,
#endif
#ifndef CONFIG_TINY_RCU
	&rcu_expedited_attr.attr,
	&rcu_normal_attr.attr,
#endif
	NULL
};

static const struct attribute_group kernel_attr_group = {
	.attrs = kernel_attrs,
};

static int __init ksysfs_init(void)
{
	int error;

	kernel_kobj = kobject_create_and_add("kernel", NULL);
	if (!kernel_kobj) {
		error = -ENOMEM;
		goto exit;
	}
	error = sysfs_create_group(kernel_kobj, &kernel_attr_group);
	if (error)
		goto kset_exit;

	if (notes_size > 0) {
		notes_attr.size = notes_size;
		error = sysfs_create_bin_file(kernel_kobj, &notes_attr);
		if (error)
			goto group_exit;
	}

	return 0;

group_exit:
	sysfs_remove_group(kernel_kobj, &kernel_attr_group);
kset_exit:
	kobject_put(kernel_kobj);
exit:
	return error;
}

core_initcall(ksysfs_init);
Commit	Line	Data
468e15fd	1	// SPDX-License-Identifier: GPL-2.0-only
1da177e4 LT	2	/*
	3	* kernel/ksysfs.c - sysfs attributes in /sys/kernel, which
	4	* are not related to any other subsystem
	5	*
	6	* Copyright (C) 2004 Kay Sievers <[email protected]>
1da177e4 LT	7	*/
1da177e4 LT	8
1da177e4 LT	9	#include <linux/kobject.h>
	10	#include <linux/string.h>
	11	#include <linux/sysfs.h>
9984de1a	12	#include <linux/export.h>
1da177e4	13	#include <linux/init.h>
c330dda9	14	#include <linux/kexec.h>
22b8ce94	15	#include <linux/profile.h>
1596425f	16	#include <linux/stat.h>
5cb350ba	17	#include <linux/sched.h>
088ab0b4	18	#include <linux/capability.h>
52f5684c	19	#include <linux/compiler.h>
1da177e4	20
5a9be7c6	21	#include <linux/rcupdate.h> /* rcu_expedited and rcu_normal */
7a754743	22
1da177e4	23	#define KERNEL_ATTR_RO(_name) \
386f275f	24	static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
1da177e4 LT	25
1da177e4 LT	26	#define KERNEL_ATTR_RW(_name) \
386f275f	27	static struct kobj_attribute _name##_attr = \
1da177e4 LT	28	__ATTR(_name, 0644, _name##_show, _name##_store)
1da177e4 LT	29
0f76e5ac	30	/* current uevent sequence number */
386f275f KS	31	static ssize_t uevent_seqnum_show(struct kobject *kobj,
386f275f KS	32	struct kobj_attribute attr, char buf)
1da177e4	33	{
386f275f	34	return sprintf(buf, "%llu\n", (unsigned long long)uevent_seqnum);
1da177e4	35	}
0f76e5ac KS	36	KERNEL_ATTR_RO(uevent_seqnum);
0f76e5ac KS	37
86d56134	38	#ifdef CONFIG_UEVENT_HELPER
af665852	39	/* uevent helper program, used during early boot */
386f275f KS	40	static ssize_t uevent_helper_show(struct kobject *kobj,
386f275f KS	41	struct kobj_attribute attr, char buf)
0f76e5ac	42	{
386f275f	43	return sprintf(buf, "%s\n", uevent_helper);
0f76e5ac	44	}
386f275f KS	45	static ssize_t uevent_helper_store(struct kobject *kobj,
	46	struct kobj_attribute *attr,
	47	const char *buf, size_t count)
0f76e5ac	48	{
312c004d	49	if (count+1 > UEVENT_HELPER_PATH_LEN)
0f76e5ac	50	return -ENOENT;
386f275f	51	memcpy(uevent_helper, buf, count);
312c004d KS	52	uevent_helper[count] = '\0';
	53	if (count && uevent_helper[count-1] == '\n')
	54	uevent_helper[count-1] = '\0';
0f76e5ac KS	55	return count;
	56	}
	57	KERNEL_ATTR_RW(uevent_helper);
86d56134	58	#endif
1da177e4	59
22b8ce94 DH	60	#ifdef CONFIG_PROFILING
	61	static ssize_t profiling_show(struct kobject *kobj,
	62	struct kobj_attribute attr, char buf)
	63	{
	64	return sprintf(buf, "%d\n", prof_on);
	65	}
	66	static ssize_t profiling_store(struct kobject *kobj,
	67	struct kobj_attribute *attr,
	68	const char *buf, size_t count)
	69	{
	70	int ret;
	71
	72	if (prof_on)
	73	return -EEXIST;
	74	/*
	75	* This eventually calls into get_option() which
	76	* has a ton of callers and is not const. It is
	77	* easiest to cast it away here.
	78	*/
	79	profile_setup((char *)buf);
	80	ret = profile_init();
	81	if (ret)
	82	return ret;
	83	ret = create_proc_profile();
	84	if (ret)
	85	return ret;
	86	return count;
	87	}
	88	KERNEL_ATTR_RW(profiling);
	89	#endif
	90
2965faa5	91	#ifdef CONFIG_KEXEC_CORE
386f275f KS	92	static ssize_t kexec_loaded_show(struct kobject *kobj,
386f275f KS	93	struct kobj_attribute attr, char buf)
c330dda9	94	{
386f275f	95	return sprintf(buf, "%d\n", !!kexec_image);
c330dda9 JM	96	}
	97	KERNEL_ATTR_RO(kexec_loaded);
	98
386f275f KS	99	static ssize_t kexec_crash_loaded_show(struct kobject *kobj,
386f275f KS	100	struct kobj_attribute attr, char buf)
c330dda9	101	{
21db79e8	102	return sprintf(buf, "%d\n", kexec_crash_loaded());
c330dda9 JM	103	}
c330dda9 JM	104	KERNEL_ATTR_RO(kexec_crash_loaded);
fd59d231	105
06a7f711 AW	106	static ssize_t kexec_crash_size_show(struct kobject *kobj,
	107	struct kobj_attribute attr, char buf)
	108	{
	109	return sprintf(buf, "%zu\n", crash_get_memory_size());
	110	}
	111	static ssize_t kexec_crash_size_store(struct kobject *kobj,
	112	struct kobj_attribute *attr,
	113	const char *buf, size_t count)
	114	{
	115	unsigned long cnt;
	116	int ret;
	117
6072ddc8	118	if (kstrtoul(buf, 0, &cnt))
06a7f711 AW	119	return -EINVAL;
	120
	121	ret = crash_shrink_memory(cnt);
	122	return ret < 0 ? ret : count;
	123	}
	124	KERNEL_ATTR_RW(kexec_crash_size);
	125
692f66f2 HB	126	#endif /* CONFIG_KEXEC_CORE */
	127
	128	#ifdef CONFIG_CRASH_CORE
	129
386f275f KS	130	static ssize_t vmcoreinfo_show(struct kobject *kobj,
386f275f KS	131	struct kobj_attribute attr, char buf)
fd59d231	132	{
dae28018 RK	133	phys_addr_t vmcore_base = paddr_vmcoreinfo_note();
dae28018 RK	134	return sprintf(buf, "%pa %x\n", &vmcore_base,
203e9e41	135	(unsigned int)VMCOREINFO_NOTE_SIZE);
fd59d231 KO	136	}
	137	KERNEL_ATTR_RO(vmcoreinfo);
	138
692f66f2	139	#endif /* CONFIG_CRASH_CORE */
c330dda9	140
088ab0b4 LN	141	/* whether file capabilities are enabled */
	142	static ssize_t fscaps_show(struct kobject *kobj,
	143	struct kobj_attribute attr, char buf)
	144	{
	145	return sprintf(buf, "%d\n", file_caps_enabled);
	146	}
	147	KERNEL_ATTR_RO(fscaps);
	148
79cfea02	149	#ifndef CONFIG_TINY_RCU
3705b88d AM	150	int rcu_expedited;
	151	static ssize_t rcu_expedited_show(struct kobject *kobj,
	152	struct kobj_attribute attr, char buf)
	153	{
5a9be7c6	154	return sprintf(buf, "%d\n", READ_ONCE(rcu_expedited));
3705b88d AM	155	}
	156	static ssize_t rcu_expedited_store(struct kobject *kobj,
	157	struct kobj_attribute *attr,
	158	const char *buf, size_t count)
	159	{
	160	if (kstrtoint(buf, 0, &rcu_expedited))
	161	return -EINVAL;
	162
	163	return count;
	164	}
	165	KERNEL_ATTR_RW(rcu_expedited);
	166
5a9be7c6 PM	167	int rcu_normal;
	168	static ssize_t rcu_normal_show(struct kobject *kobj,
	169	struct kobj_attribute attr, char buf)
	170	{
	171	return sprintf(buf, "%d\n", READ_ONCE(rcu_normal));
	172	}
	173	static ssize_t rcu_normal_store(struct kobject *kobj,
	174	struct kobj_attribute *attr,
	175	const char *buf, size_t count)
	176	{
	177	if (kstrtoint(buf, 0, &rcu_normal))
	178	return -EINVAL;
	179
	180	return count;
	181	}
	182	KERNEL_ATTR_RW(rcu_normal);
79cfea02	183	#endif /* #ifndef CONFIG_TINY_RCU */
5a9be7c6	184
da1a679c RM	185	/*
	186	* Make /sys/kernel/notes give the raw contents of our kernel .notes section.
	187	*/
52f5684c GID	188	extern const void __start_notes __weak;
52f5684c GID	189	extern const void __stop_notes __weak;
da1a679c RM	190	#define notes_size (&__stop_notes - &__start_notes)
da1a679c RM	191
2c3c8bea CW	192	static ssize_t notes_read(struct file filp, struct kobject kobj,
2c3c8bea CW	193	struct bin_attribute *bin_attr,
da1a679c RM	194	char *buf, loff_t off, size_t count)
	195	{
	196	memcpy(buf, &__start_notes + off, count);
	197	return count;
	198	}
	199
738bc38d	200	static struct bin_attribute notes_attr __ro_after_init = {
da1a679c RM	201	.attr = {
	202	.name = "notes",
	203	.mode = S_IRUGO,
	204	},
	205	.read = &notes_read,
	206	};
	207
0ff21e46 GKH	208	struct kobject *kernel_kobj;
0ff21e46 GKH	209	EXPORT_SYMBOL_GPL(kernel_kobj);
1da177e4 LT	210
1da177e4 LT	211	static struct attribute * kernel_attrs[] = {
088ab0b4	212	&fscaps_attr.attr,
0f76e5ac	213	&uevent_seqnum_attr.attr,
86d56134	214	#ifdef CONFIG_UEVENT_HELPER
0f76e5ac	215	&uevent_helper_attr.attr,
86d56134	216	#endif
22b8ce94 DH	217	#ifdef CONFIG_PROFILING
	218	&profiling_attr.attr,
	219	#endif
2965faa5	220	#ifdef CONFIG_KEXEC_CORE
c330dda9 JM	221	&kexec_loaded_attr.attr,
c330dda9 JM	222	&kexec_crash_loaded_attr.attr,
06a7f711	223	&kexec_crash_size_attr.attr,
692f66f2 HB	224	#endif
692f66f2 HB	225	#ifdef CONFIG_CRASH_CORE
fd59d231	226	&vmcoreinfo_attr.attr,
1da177e4	227	#endif
79cfea02	228	#ifndef CONFIG_TINY_RCU
3705b88d	229	&rcu_expedited_attr.attr,
5a9be7c6	230	&rcu_normal_attr.attr,
79cfea02	231	#endif
1da177e4 LT	232	NULL
	233	};
	234
9dcdcea1	235	static const struct attribute_group kernel_attr_group = {
1da177e4 LT	236	.attrs = kernel_attrs,
	237	};
	238
	239	static int __init ksysfs_init(void)
	240	{
bd35b93d	241	int error;
1da177e4	242
0ff21e46 GKH	243	kernel_kobj = kobject_create_and_add("kernel", NULL);
0ff21e46 GKH	244	if (!kernel_kobj) {
bd35b93d GKH	245	error = -ENOMEM;
	246	goto exit;
	247	}
0ff21e46	248	error = sysfs_create_group(kernel_kobj, &kernel_attr_group);
bd35b93d GKH	249	if (error)
	250	goto kset_exit;
	251
	252	if (notes_size > 0) {
da1a679c	253	notes_attr.size = notes_size;
0ff21e46	254	error = sysfs_create_bin_file(kernel_kobj, &notes_attr);
bd35b93d GKH	255	if (error)
bd35b93d GKH	256	goto group_exit;
da1a679c RM	257	}
da1a679c RM	258
bd35b93d GKH	259	return 0;
bd35b93d GKH	260
bd35b93d	261	group_exit:
0ff21e46	262	sysfs_remove_group(kernel_kobj, &kernel_attr_group);
bd35b93d	263	kset_exit:
78a2d906	264	kobject_put(kernel_kobj);
bd35b93d	265	exit:
1da177e4 LT	266	return error;
	267	}
	268
	269	core_initcall(ksysfs_init);