[linux-2.6-block.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 <kay.sievers@vrfy.org>
 */

#include <asm/byteorder.h>
#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 */

#if defined(__LITTLE_ENDIAN)
#define CPU_BYTEORDER_STRING	"little"
#elif defined(__BIG_ENDIAN)
#define CPU_BYTEORDER_STRING	"big"
#else
#error Unknown byteorder
#endif

#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);

/* cpu byteorder */
static ssize_t cpu_byteorder_show(struct kobject *kobj,
				  struct kobj_attribute *attr, char *buf)
{
	return sysfs_emit(buf, "%s\n", CPU_BYTEORDER_STRING);
}
KERNEL_ATTR_RO(cpu_byteorder);

#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,
	&cpu_byteorder_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 <kay.sievers@vrfy.org>
1da177e4 LT	7	*/
1da177e4 LT	8
d3d76fbd	9	#include <asm/byteorder.h>
1da177e4 LT	10	#include <linux/kobject.h>
	11	#include <linux/string.h>
	12	#include <linux/sysfs.h>
9984de1a	13	#include <linux/export.h>
1da177e4	14	#include <linux/init.h>
c330dda9	15	#include <linux/kexec.h>
22b8ce94	16	#include <linux/profile.h>
1596425f	17	#include <linux/stat.h>
5cb350ba	18	#include <linux/sched.h>
088ab0b4	19	#include <linux/capability.h>
52f5684c	20	#include <linux/compiler.h>
1da177e4	21
5a9be7c6	22	#include <linux/rcupdate.h> /* rcu_expedited and rcu_normal */
7a754743	23
d3d76fbd TW	24	#if defined(__LITTLE_ENDIAN)
	25	#define CPU_BYTEORDER_STRING "little"
	26	#elif defined(__BIG_ENDIAN)
	27	#define CPU_BYTEORDER_STRING "big"
	28	#else
	29	#error Unknown byteorder
	30	#endif
	31
1da177e4	32	#define KERNEL_ATTR_RO(_name) \
386f275f	33	static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
1da177e4 LT	34
1da177e4 LT	35	#define KERNEL_ATTR_RW(_name) \
a7cd9a53	36	static struct kobj_attribute _name##_attr = __ATTR_RW(_name)
1da177e4	37
0f76e5ac	38	/* current uevent sequence number */
386f275f KS	39	static ssize_t uevent_seqnum_show(struct kobject *kobj,
386f275f KS	40	struct kobj_attribute attr, char buf)
1da177e4	41	{
386f275f	42	return sprintf(buf, "%llu\n", (unsigned long long)uevent_seqnum);
1da177e4	43	}
0f76e5ac KS	44	KERNEL_ATTR_RO(uevent_seqnum);
0f76e5ac KS	45
d3d76fbd TW	46	/* cpu byteorder */
	47	static ssize_t cpu_byteorder_show(struct kobject *kobj,
	48	struct kobj_attribute attr, char buf)
	49	{
	50	return sysfs_emit(buf, "%s\n", CPU_BYTEORDER_STRING);
	51	}
	52	KERNEL_ATTR_RO(cpu_byteorder);
	53
86d56134	54	#ifdef CONFIG_UEVENT_HELPER
af665852	55	/* uevent helper program, used during early boot */
386f275f KS	56	static ssize_t uevent_helper_show(struct kobject *kobj,
386f275f KS	57	struct kobj_attribute attr, char buf)
0f76e5ac	58	{
386f275f	59	return sprintf(buf, "%s\n", uevent_helper);
0f76e5ac	60	}
386f275f KS	61	static ssize_t uevent_helper_store(struct kobject *kobj,
	62	struct kobj_attribute *attr,
	63	const char *buf, size_t count)
0f76e5ac	64	{
312c004d	65	if (count+1 > UEVENT_HELPER_PATH_LEN)
0f76e5ac	66	return -ENOENT;
386f275f	67	memcpy(uevent_helper, buf, count);
312c004d KS	68	uevent_helper[count] = '\0';
	69	if (count && uevent_helper[count-1] == '\n')
	70	uevent_helper[count-1] = '\0';
0f76e5ac KS	71	return count;
	72	}
	73	KERNEL_ATTR_RW(uevent_helper);
86d56134	74	#endif
1da177e4	75
22b8ce94 DH	76	#ifdef CONFIG_PROFILING
	77	static ssize_t profiling_show(struct kobject *kobj,
	78	struct kobj_attribute attr, char buf)
	79	{
	80	return sprintf(buf, "%d\n", prof_on);
	81	}
	82	static ssize_t profiling_store(struct kobject *kobj,
	83	struct kobj_attribute *attr,
	84	const char *buf, size_t count)
	85	{
	86	int ret;
	87
	88	if (prof_on)
	89	return -EEXIST;
	90	/*
	91	* This eventually calls into get_option() which
	92	* has a ton of callers and is not const. It is
	93	* easiest to cast it away here.
	94	*/
	95	profile_setup((char *)buf);
	96	ret = profile_init();
	97	if (ret)
	98	return ret;
	99	ret = create_proc_profile();
	100	if (ret)
	101	return ret;
	102	return count;
	103	}
	104	KERNEL_ATTR_RW(profiling);
	105	#endif
	106
2965faa5	107	#ifdef CONFIG_KEXEC_CORE
386f275f KS	108	static ssize_t kexec_loaded_show(struct kobject *kobj,
386f275f KS	109	struct kobj_attribute attr, char buf)
c330dda9	110	{
386f275f	111	return sprintf(buf, "%d\n", !!kexec_image);
c330dda9 JM	112	}
	113	KERNEL_ATTR_RO(kexec_loaded);
	114
386f275f KS	115	static ssize_t kexec_crash_loaded_show(struct kobject *kobj,
386f275f KS	116	struct kobj_attribute attr, char buf)
c330dda9	117	{
21db79e8	118	return sprintf(buf, "%d\n", kexec_crash_loaded());
c330dda9 JM	119	}
c330dda9 JM	120	KERNEL_ATTR_RO(kexec_crash_loaded);
fd59d231	121
06a7f711 AW	122	static ssize_t kexec_crash_size_show(struct kobject *kobj,
	123	struct kobj_attribute attr, char buf)
	124	{
7bb5da0d VS	125	ssize_t size = crash_get_memory_size();
	126
	127	if (size < 0)
	128	return size;
	129
	130	return sprintf(buf, "%zd\n", size);
06a7f711 AW	131	}
	132	static ssize_t kexec_crash_size_store(struct kobject *kobj,
	133	struct kobj_attribute *attr,
	134	const char *buf, size_t count)
	135	{
	136	unsigned long cnt;
	137	int ret;
	138
6072ddc8	139	if (kstrtoul(buf, 0, &cnt))
06a7f711 AW	140	return -EINVAL;
	141
	142	ret = crash_shrink_memory(cnt);
	143	return ret < 0 ? ret : count;
	144	}
	145	KERNEL_ATTR_RW(kexec_crash_size);
	146
692f66f2 HB	147	#endif /* CONFIG_KEXEC_CORE */
	148
	149	#ifdef CONFIG_CRASH_CORE
	150
386f275f KS	151	static ssize_t vmcoreinfo_show(struct kobject *kobj,
386f275f KS	152	struct kobj_attribute attr, char buf)
fd59d231	153	{
dae28018 RK	154	phys_addr_t vmcore_base = paddr_vmcoreinfo_note();
dae28018 RK	155	return sprintf(buf, "%pa %x\n", &vmcore_base,
203e9e41	156	(unsigned int)VMCOREINFO_NOTE_SIZE);
fd59d231 KO	157	}
	158	KERNEL_ATTR_RO(vmcoreinfo);
	159
692f66f2	160	#endif /* CONFIG_CRASH_CORE */
c330dda9	161
088ab0b4 LN	162	/* whether file capabilities are enabled */
	163	static ssize_t fscaps_show(struct kobject *kobj,
	164	struct kobj_attribute attr, char buf)
	165	{
	166	return sprintf(buf, "%d\n", file_caps_enabled);
	167	}
	168	KERNEL_ATTR_RO(fscaps);
	169
79cfea02	170	#ifndef CONFIG_TINY_RCU
3705b88d AM	171	int rcu_expedited;
	172	static ssize_t rcu_expedited_show(struct kobject *kobj,
	173	struct kobj_attribute attr, char buf)
	174	{
5a9be7c6	175	return sprintf(buf, "%d\n", READ_ONCE(rcu_expedited));
3705b88d AM	176	}
	177	static ssize_t rcu_expedited_store(struct kobject *kobj,
	178	struct kobj_attribute *attr,
	179	const char *buf, size_t count)
	180	{
	181	if (kstrtoint(buf, 0, &rcu_expedited))
	182	return -EINVAL;
	183
	184	return count;
	185	}
	186	KERNEL_ATTR_RW(rcu_expedited);
	187
5a9be7c6 PM	188	int rcu_normal;
	189	static ssize_t rcu_normal_show(struct kobject *kobj,
	190	struct kobj_attribute attr, char buf)
	191	{
	192	return sprintf(buf, "%d\n", READ_ONCE(rcu_normal));
	193	}
	194	static ssize_t rcu_normal_store(struct kobject *kobj,
	195	struct kobj_attribute *attr,
	196	const char *buf, size_t count)
	197	{
	198	if (kstrtoint(buf, 0, &rcu_normal))
	199	return -EINVAL;
	200
	201	return count;
	202	}
	203	KERNEL_ATTR_RW(rcu_normal);
79cfea02	204	#endif /* #ifndef CONFIG_TINY_RCU */
5a9be7c6	205
da1a679c RM	206	/*
	207	* Make /sys/kernel/notes give the raw contents of our kernel .notes section.
	208	*/
52f5684c GID	209	extern const void __start_notes __weak;
52f5684c GID	210	extern const void __stop_notes __weak;
da1a679c RM	211	#define notes_size (&__stop_notes - &__start_notes)
da1a679c RM	212
2c3c8bea CW	213	static ssize_t notes_read(struct file filp, struct kobject kobj,
2c3c8bea CW	214	struct bin_attribute *bin_attr,
da1a679c RM	215	char *buf, loff_t off, size_t count)
	216	{
	217	memcpy(buf, &__start_notes + off, count);
	218	return count;
	219	}
	220
738bc38d	221	static struct bin_attribute notes_attr __ro_after_init = {
da1a679c RM	222	.attr = {
	223	.name = "notes",
	224	.mode = S_IRUGO,
	225	},
	226	.read = &notes_read,
	227	};
	228
0ff21e46 GKH	229	struct kobject *kernel_kobj;
0ff21e46 GKH	230	EXPORT_SYMBOL_GPL(kernel_kobj);
1da177e4 LT	231
1da177e4 LT	232	static struct attribute * kernel_attrs[] = {
088ab0b4	233	&fscaps_attr.attr,
0f76e5ac	234	&uevent_seqnum_attr.attr,
d3d76fbd	235	&cpu_byteorder_attr.attr,
86d56134	236	#ifdef CONFIG_UEVENT_HELPER
0f76e5ac	237	&uevent_helper_attr.attr,
86d56134	238	#endif
22b8ce94 DH	239	#ifdef CONFIG_PROFILING
	240	&profiling_attr.attr,
	241	#endif
2965faa5	242	#ifdef CONFIG_KEXEC_CORE
c330dda9 JM	243	&kexec_loaded_attr.attr,
c330dda9 JM	244	&kexec_crash_loaded_attr.attr,
06a7f711	245	&kexec_crash_size_attr.attr,
692f66f2 HB	246	#endif
692f66f2 HB	247	#ifdef CONFIG_CRASH_CORE
fd59d231	248	&vmcoreinfo_attr.attr,
1da177e4	249	#endif
79cfea02	250	#ifndef CONFIG_TINY_RCU
3705b88d	251	&rcu_expedited_attr.attr,
5a9be7c6	252	&rcu_normal_attr.attr,
79cfea02	253	#endif
1da177e4 LT	254	NULL
	255	};
	256
9dcdcea1	257	static const struct attribute_group kernel_attr_group = {
1da177e4 LT	258	.attrs = kernel_attrs,
	259	};
	260
	261	static int __init ksysfs_init(void)
	262	{
bd35b93d	263	int error;
1da177e4	264
0ff21e46 GKH	265	kernel_kobj = kobject_create_and_add("kernel", NULL);
0ff21e46 GKH	266	if (!kernel_kobj) {
bd35b93d GKH	267	error = -ENOMEM;
	268	goto exit;
	269	}
0ff21e46	270	error = sysfs_create_group(kernel_kobj, &kernel_attr_group);
bd35b93d GKH	271	if (error)
	272	goto kset_exit;
	273
	274	if (notes_size > 0) {
da1a679c	275	notes_attr.size = notes_size;
0ff21e46	276	error = sysfs_create_bin_file(kernel_kobj, &notes_attr);
bd35b93d GKH	277	if (error)
bd35b93d GKH	278	goto group_exit;
da1a679c RM	279	}
da1a679c RM	280
bd35b93d GKH	281	return 0;
bd35b93d GKH	282
bd35b93d	283	group_exit:
0ff21e46	284	sysfs_remove_group(kernel_kobj, &kernel_attr_group);
bd35b93d	285	kset_exit:
78a2d906	286	kobject_put(kernel_kobj);
bd35b93d	287	exit:
1da177e4 LT	288	return error;
	289	}
	290
	291	core_initcall(ksysfs_init);