[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_RW(_name)

/* 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)
{
	ssize_t size = crash_get_memory_size();

	if (size < 0)
		return size;

	return sprintf(buf, "%zd\n", 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) \
a7cd9a53	27	static struct kobj_attribute _name##_attr = __ATTR_RW(_name)
1da177e4	28
0f76e5ac	29	/* current uevent sequence number */
386f275f KS	30	static ssize_t uevent_seqnum_show(struct kobject *kobj,
386f275f KS	31	struct kobj_attribute attr, char buf)
1da177e4	32	{
386f275f	33	return sprintf(buf, "%llu\n", (unsigned long long)uevent_seqnum);
1da177e4	34	}
0f76e5ac KS	35	KERNEL_ATTR_RO(uevent_seqnum);
0f76e5ac KS	36
86d56134	37	#ifdef CONFIG_UEVENT_HELPER
af665852	38	/* uevent helper program, used during early boot */
386f275f KS	39	static ssize_t uevent_helper_show(struct kobject *kobj,
386f275f KS	40	struct kobj_attribute attr, char buf)
0f76e5ac	41	{
386f275f	42	return sprintf(buf, "%s\n", uevent_helper);
0f76e5ac	43	}
386f275f KS	44	static ssize_t uevent_helper_store(struct kobject *kobj,
	45	struct kobj_attribute *attr,
	46	const char *buf, size_t count)
0f76e5ac	47	{
312c004d	48	if (count+1 > UEVENT_HELPER_PATH_LEN)
0f76e5ac	49	return -ENOENT;
386f275f	50	memcpy(uevent_helper, buf, count);
312c004d KS	51	uevent_helper[count] = '\0';
	52	if (count && uevent_helper[count-1] == '\n')
	53	uevent_helper[count-1] = '\0';
0f76e5ac KS	54	return count;
	55	}
	56	KERNEL_ATTR_RW(uevent_helper);
86d56134	57	#endif
1da177e4	58
22b8ce94 DH	59	#ifdef CONFIG_PROFILING
	60	static ssize_t profiling_show(struct kobject *kobj,
	61	struct kobj_attribute attr, char buf)
	62	{
	63	return sprintf(buf, "%d\n", prof_on);
	64	}
	65	static ssize_t profiling_store(struct kobject *kobj,
	66	struct kobj_attribute *attr,
	67	const char *buf, size_t count)
	68	{
	69	int ret;
	70
	71	if (prof_on)
	72	return -EEXIST;
	73	/*
	74	* This eventually calls into get_option() which
	75	* has a ton of callers and is not const. It is
	76	* easiest to cast it away here.
	77	*/
	78	profile_setup((char *)buf);
	79	ret = profile_init();
	80	if (ret)
	81	return ret;
	82	ret = create_proc_profile();
	83	if (ret)
	84	return ret;
	85	return count;
	86	}
	87	KERNEL_ATTR_RW(profiling);
	88	#endif
	89
2965faa5	90	#ifdef CONFIG_KEXEC_CORE
386f275f KS	91	static ssize_t kexec_loaded_show(struct kobject *kobj,
386f275f KS	92	struct kobj_attribute attr, char buf)
c330dda9	93	{
386f275f	94	return sprintf(buf, "%d\n", !!kexec_image);
c330dda9 JM	95	}
	96	KERNEL_ATTR_RO(kexec_loaded);
	97
386f275f KS	98	static ssize_t kexec_crash_loaded_show(struct kobject *kobj,
386f275f KS	99	struct kobj_attribute attr, char buf)
c330dda9	100	{
21db79e8	101	return sprintf(buf, "%d\n", kexec_crash_loaded());
c330dda9 JM	102	}
c330dda9 JM	103	KERNEL_ATTR_RO(kexec_crash_loaded);
fd59d231	104
06a7f711 AW	105	static ssize_t kexec_crash_size_show(struct kobject *kobj,
	106	struct kobj_attribute attr, char buf)
	107	{
7bb5da0d VS	108	ssize_t size = crash_get_memory_size();
	109
	110	if (size < 0)
	111	return size;
	112
	113	return sprintf(buf, "%zd\n", size);
06a7f711 AW	114	}
	115	static ssize_t kexec_crash_size_store(struct kobject *kobj,
	116	struct kobj_attribute *attr,
	117	const char *buf, size_t count)
	118	{
	119	unsigned long cnt;
	120	int ret;
	121
6072ddc8	122	if (kstrtoul(buf, 0, &cnt))
06a7f711 AW	123	return -EINVAL;
	124
	125	ret = crash_shrink_memory(cnt);
	126	return ret < 0 ? ret : count;
	127	}
	128	KERNEL_ATTR_RW(kexec_crash_size);
	129
692f66f2 HB	130	#endif /* CONFIG_KEXEC_CORE */
	131
	132	#ifdef CONFIG_CRASH_CORE
	133
386f275f KS	134	static ssize_t vmcoreinfo_show(struct kobject *kobj,
386f275f KS	135	struct kobj_attribute attr, char buf)
fd59d231	136	{
dae28018 RK	137	phys_addr_t vmcore_base = paddr_vmcoreinfo_note();
dae28018 RK	138	return sprintf(buf, "%pa %x\n", &vmcore_base,
203e9e41	139	(unsigned int)VMCOREINFO_NOTE_SIZE);
fd59d231 KO	140	}
	141	KERNEL_ATTR_RO(vmcoreinfo);
	142
692f66f2	143	#endif /* CONFIG_CRASH_CORE */
c330dda9	144
088ab0b4 LN	145	/* whether file capabilities are enabled */
	146	static ssize_t fscaps_show(struct kobject *kobj,
	147	struct kobj_attribute attr, char buf)
	148	{
	149	return sprintf(buf, "%d\n", file_caps_enabled);
	150	}
	151	KERNEL_ATTR_RO(fscaps);
	152
79cfea02	153	#ifndef CONFIG_TINY_RCU
3705b88d AM	154	int rcu_expedited;
	155	static ssize_t rcu_expedited_show(struct kobject *kobj,
	156	struct kobj_attribute attr, char buf)
	157	{
5a9be7c6	158	return sprintf(buf, "%d\n", READ_ONCE(rcu_expedited));
3705b88d AM	159	}
	160	static ssize_t rcu_expedited_store(struct kobject *kobj,
	161	struct kobj_attribute *attr,
	162	const char *buf, size_t count)
	163	{
	164	if (kstrtoint(buf, 0, &rcu_expedited))
	165	return -EINVAL;
	166
	167	return count;
	168	}
	169	KERNEL_ATTR_RW(rcu_expedited);
	170
5a9be7c6 PM	171	int rcu_normal;
	172	static ssize_t rcu_normal_show(struct kobject *kobj,
	173	struct kobj_attribute attr, char buf)
	174	{
	175	return sprintf(buf, "%d\n", READ_ONCE(rcu_normal));
	176	}
	177	static ssize_t rcu_normal_store(struct kobject *kobj,
	178	struct kobj_attribute *attr,
	179	const char *buf, size_t count)
	180	{
	181	if (kstrtoint(buf, 0, &rcu_normal))
	182	return -EINVAL;
	183
	184	return count;
	185	}
	186	KERNEL_ATTR_RW(rcu_normal);
79cfea02	187	#endif /* #ifndef CONFIG_TINY_RCU */
5a9be7c6	188
da1a679c RM	189	/*
	190	* Make /sys/kernel/notes give the raw contents of our kernel .notes section.
	191	*/
52f5684c GID	192	extern const void __start_notes __weak;
52f5684c GID	193	extern const void __stop_notes __weak;
da1a679c RM	194	#define notes_size (&__stop_notes - &__start_notes)
da1a679c RM	195
2c3c8bea CW	196	static ssize_t notes_read(struct file filp, struct kobject kobj,
2c3c8bea CW	197	struct bin_attribute *bin_attr,
da1a679c RM	198	char *buf, loff_t off, size_t count)
	199	{
	200	memcpy(buf, &__start_notes + off, count);
	201	return count;
	202	}
	203
738bc38d	204	static struct bin_attribute notes_attr __ro_after_init = {
da1a679c RM	205	.attr = {
	206	.name = "notes",
	207	.mode = S_IRUGO,
	208	},
	209	.read = &notes_read,
	210	};
	211
0ff21e46 GKH	212	struct kobject *kernel_kobj;
0ff21e46 GKH	213	EXPORT_SYMBOL_GPL(kernel_kobj);
1da177e4 LT	214
1da177e4 LT	215	static struct attribute * kernel_attrs[] = {
088ab0b4	216	&fscaps_attr.attr,
0f76e5ac	217	&uevent_seqnum_attr.attr,
86d56134	218	#ifdef CONFIG_UEVENT_HELPER
0f76e5ac	219	&uevent_helper_attr.attr,
86d56134	220	#endif
22b8ce94 DH	221	#ifdef CONFIG_PROFILING
	222	&profiling_attr.attr,
	223	#endif
2965faa5	224	#ifdef CONFIG_KEXEC_CORE
c330dda9 JM	225	&kexec_loaded_attr.attr,
c330dda9 JM	226	&kexec_crash_loaded_attr.attr,
06a7f711	227	&kexec_crash_size_attr.attr,
692f66f2 HB	228	#endif
692f66f2 HB	229	#ifdef CONFIG_CRASH_CORE
fd59d231	230	&vmcoreinfo_attr.attr,
1da177e4	231	#endif
79cfea02	232	#ifndef CONFIG_TINY_RCU
3705b88d	233	&rcu_expedited_attr.attr,
5a9be7c6	234	&rcu_normal_attr.attr,
79cfea02	235	#endif
1da177e4 LT	236	NULL
	237	};
	238
9dcdcea1	239	static const struct attribute_group kernel_attr_group = {
1da177e4 LT	240	.attrs = kernel_attrs,
	241	};
	242
	243	static int __init ksysfs_init(void)
	244	{
bd35b93d	245	int error;
1da177e4	246
0ff21e46 GKH	247	kernel_kobj = kobject_create_and_add("kernel", NULL);
0ff21e46 GKH	248	if (!kernel_kobj) {
bd35b93d GKH	249	error = -ENOMEM;
	250	goto exit;
	251	}
0ff21e46	252	error = sysfs_create_group(kernel_kobj, &kernel_attr_group);
bd35b93d GKH	253	if (error)
	254	goto kset_exit;
	255
	256	if (notes_size > 0) {
da1a679c	257	notes_attr.size = notes_size;
0ff21e46	258	error = sysfs_create_bin_file(kernel_kobj, &notes_attr);
bd35b93d GKH	259	if (error)
bd35b93d GKH	260	goto group_exit;
da1a679c RM	261	}
da1a679c RM	262
bd35b93d GKH	263	return 0;
bd35b93d GKH	264
bd35b93d	265	group_exit:
0ff21e46	266	sysfs_remove_group(kernel_kobj, &kernel_attr_group);
bd35b93d	267	kset_exit:
78a2d906	268	kobject_put(kernel_kobj);
bd35b93d	269	exit:
1da177e4 LT	270	return error;
	271	}
	272
	273	core_initcall(ksysfs_init);