[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 sysfs_emit(buf, "%llu\n", (u64)atomic64_read(&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);

/* address bits */
static ssize_t address_bits_show(struct kobject *kobj,
				 struct kobj_attribute *attr, char *buf)
{
	return sysfs_emit(buf, "%zu\n", sizeof(void *) * 8 /* CHAR_BIT */);
}
KERNEL_ATTR_RO(address_bits);

#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 sysfs_emit(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 sysfs_emit(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;
	static DEFINE_MUTEX(lock);

	/*
	 * We need serialization, for profile_setup() initializes prof_on
	 * value and profile_init() must not reallocate prof_buffer after
	 * once allocated.
	 */
	guard(mutex)(&lock);
	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 sysfs_emit(buf, "%d\n", !!kexec_image);
}
KERNEL_ATTR_RO(kexec_loaded);

#ifdef CONFIG_CRASH_DUMP
static ssize_t kexec_crash_loaded_show(struct kobject *kobj,
				       struct kobj_attribute *attr, char *buf)
{
	return sysfs_emit(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 sysfs_emit(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_CRASH_DUMP*/
#endif /* CONFIG_KEXEC_CORE */

#ifdef CONFIG_VMCORE_INFO

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

#ifdef CONFIG_CRASH_HOTPLUG
static ssize_t crash_elfcorehdr_size_show(struct kobject *kobj,
			       struct kobj_attribute *attr, char *buf)
{
	unsigned int sz = crash_get_elfcorehdr_size();

	return sysfs_emit(buf, "%u\n", sz);
}
KERNEL_ATTR_RO(crash_elfcorehdr_size);

#endif

#endif /* CONFIG_VMCORE_INFO */

/* whether file capabilities are enabled */
static ssize_t fscaps_show(struct kobject *kobj,
				  struct kobj_attribute *attr, char *buf)
{
	return sysfs_emit(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 sysfs_emit(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 sysfs_emit(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;
extern const void __stop_notes;
#define	notes_size (&__stop_notes - &__start_notes)

static __ro_after_init BIN_ATTR_SIMPLE_RO(notes);

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,
	&address_bits_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,
#ifdef CONFIG_CRASH_DUMP
	&kexec_crash_loaded_attr.attr,
	&kexec_crash_size_attr.attr,
#endif
#endif
#ifdef CONFIG_VMCORE_INFO
	&vmcoreinfo_attr.attr,
#ifdef CONFIG_CRASH_HOTPLUG
	&crash_elfcorehdr_size_attr.attr,
#endif
#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) {
		bin_attr_notes.private = (void *)&__start_notes;
		bin_attr_notes.size = notes_size;
		error = sysfs_create_bin_file(kernel_kobj, &bin_attr_notes);
		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	{
2444a80c	42	return sysfs_emit(buf, "%llu\n", (u64)atomic64_read(&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
00142bfd TW	54	/* address bits */
	55	static ssize_t address_bits_show(struct kobject *kobj,
	56	struct kobj_attribute attr, char buf)
	57	{
	58	return sysfs_emit(buf, "%zu\n", sizeof(void ) 8 /* CHAR_BIT */);
	59	}
	60	KERNEL_ATTR_RO(address_bits);
	61
86d56134	62	#ifdef CONFIG_UEVENT_HELPER
af665852	63	/* uevent helper program, used during early boot */
386f275f KS	64	static ssize_t uevent_helper_show(struct kobject *kobj,
386f275f KS	65	struct kobj_attribute attr, char buf)
0f76e5ac	66	{
9f33a88c	67	return sysfs_emit(buf, "%s\n", uevent_helper);
0f76e5ac	68	}
386f275f KS	69	static ssize_t uevent_helper_store(struct kobject *kobj,
	70	struct kobj_attribute *attr,
	71	const char *buf, size_t count)
0f76e5ac	72	{
312c004d	73	if (count+1 > UEVENT_HELPER_PATH_LEN)
0f76e5ac	74	return -ENOENT;
386f275f	75	memcpy(uevent_helper, buf, count);
312c004d KS	76	uevent_helper[count] = '\0';
	77	if (count && uevent_helper[count-1] == '\n')
	78	uevent_helper[count-1] = '\0';
0f76e5ac KS	79	return count;
	80	}
	81	KERNEL_ATTR_RW(uevent_helper);
86d56134	82	#endif
1da177e4	83
22b8ce94 DH	84	#ifdef CONFIG_PROFILING
	85	static ssize_t profiling_show(struct kobject *kobj,
	86	struct kobj_attribute attr, char buf)
	87	{
9f33a88c	88	return sysfs_emit(buf, "%d\n", prof_on);
22b8ce94 DH	89	}
	90	static ssize_t profiling_store(struct kobject *kobj,
	91	struct kobj_attribute *attr,
	92	const char *buf, size_t count)
	93	{
	94	int ret;
7c51f7bb	95	static DEFINE_MUTEX(lock);
22b8ce94	96
7c51f7bb TH	97	/*
	98	* We need serialization, for profile_setup() initializes prof_on
	99	* value and profile_init() must not reallocate prof_buffer after
	100	* once allocated.
	101	*/
	102	guard(mutex)(&lock);
22b8ce94 DH	103	if (prof_on)
	104	return -EEXIST;
	105	/*
	106	* This eventually calls into get_option() which
	107	* has a ton of callers and is not const. It is
	108	* easiest to cast it away here.
	109	*/
	110	profile_setup((char *)buf);
	111	ret = profile_init();
	112	if (ret)
	113	return ret;
	114	ret = create_proc_profile();
	115	if (ret)
	116	return ret;
	117	return count;
	118	}
	119	KERNEL_ATTR_RW(profiling);
	120	#endif
	121
2965faa5	122	#ifdef CONFIG_KEXEC_CORE
386f275f KS	123	static ssize_t kexec_loaded_show(struct kobject *kobj,
386f275f KS	124	struct kobj_attribute attr, char buf)
c330dda9	125	{
9f33a88c	126	return sysfs_emit(buf, "%d\n", !!kexec_image);
c330dda9 JM	127	}
	128	KERNEL_ATTR_RO(kexec_loaded);
	129
02aff848	130	#ifdef CONFIG_CRASH_DUMP
386f275f KS	131	static ssize_t kexec_crash_loaded_show(struct kobject *kobj,
386f275f KS	132	struct kobj_attribute attr, char buf)
c330dda9	133	{
9f33a88c	134	return sysfs_emit(buf, "%d\n", kexec_crash_loaded());
c330dda9 JM	135	}
c330dda9 JM	136	KERNEL_ATTR_RO(kexec_crash_loaded);
fd59d231	137
06a7f711 AW	138	static ssize_t kexec_crash_size_show(struct kobject *kobj,
	139	struct kobj_attribute attr, char buf)
	140	{
7bb5da0d VS	141	ssize_t size = crash_get_memory_size();
	142
	143	if (size < 0)
	144	return size;
	145
9f33a88c	146	return sysfs_emit(buf, "%zd\n", size);
06a7f711 AW	147	}
	148	static ssize_t kexec_crash_size_store(struct kobject *kobj,
	149	struct kobj_attribute *attr,
	150	const char *buf, size_t count)
	151	{
	152	unsigned long cnt;
	153	int ret;
	154
6072ddc8	155	if (kstrtoul(buf, 0, &cnt))
06a7f711 AW	156	return -EINVAL;
	157
	158	ret = crash_shrink_memory(cnt);
	159	return ret < 0 ? ret : count;
	160	}
	161	KERNEL_ATTR_RW(kexec_crash_size);
	162
02aff848	163	#endif /* CONFIG_CRASH_DUMP*/
692f66f2 HB	164	#endif /* CONFIG_KEXEC_CORE */
692f66f2 HB	165
443cbaf9	166	#ifdef CONFIG_VMCORE_INFO
692f66f2	167
386f275f KS	168	static ssize_t vmcoreinfo_show(struct kobject *kobj,
386f275f KS	169	struct kobj_attribute attr, char buf)
fd59d231	170	{
dae28018	171	phys_addr_t vmcore_base = paddr_vmcoreinfo_note();
9f33a88c TW	172	return sysfs_emit(buf, "%pa %x\n", &vmcore_base,
9f33a88c TW	173	(unsigned int)VMCOREINFO_NOTE_SIZE);
fd59d231 KO	174	}
	175	KERNEL_ATTR_RO(vmcoreinfo);
	176
a72bbec7 ED	177	#ifdef CONFIG_CRASH_HOTPLUG
	178	static ssize_t crash_elfcorehdr_size_show(struct kobject *kobj,
	179	struct kobj_attribute attr, char buf)
	180	{
	181	unsigned int sz = crash_get_elfcorehdr_size();
	182
	183	return sysfs_emit(buf, "%u\n", sz);
	184	}
	185	KERNEL_ATTR_RO(crash_elfcorehdr_size);
	186
	187	#endif
	188
443cbaf9	189	#endif /* CONFIG_VMCORE_INFO */
c330dda9	190
088ab0b4 LN	191	/* whether file capabilities are enabled */
	192	static ssize_t fscaps_show(struct kobject *kobj,
	193	struct kobj_attribute attr, char buf)
	194	{
9f33a88c	195	return sysfs_emit(buf, "%d\n", file_caps_enabled);
088ab0b4 LN	196	}
	197	KERNEL_ATTR_RO(fscaps);
	198
79cfea02	199	#ifndef CONFIG_TINY_RCU
3705b88d AM	200	int rcu_expedited;
	201	static ssize_t rcu_expedited_show(struct kobject *kobj,
	202	struct kobj_attribute attr, char buf)
	203	{
9f33a88c	204	return sysfs_emit(buf, "%d\n", READ_ONCE(rcu_expedited));
3705b88d AM	205	}
	206	static ssize_t rcu_expedited_store(struct kobject *kobj,
	207	struct kobj_attribute *attr,
	208	const char *buf, size_t count)
	209	{
	210	if (kstrtoint(buf, 0, &rcu_expedited))
	211	return -EINVAL;
	212
	213	return count;
	214	}
	215	KERNEL_ATTR_RW(rcu_expedited);
	216
5a9be7c6 PM	217	int rcu_normal;
	218	static ssize_t rcu_normal_show(struct kobject *kobj,
	219	struct kobj_attribute attr, char buf)
	220	{
9f33a88c	221	return sysfs_emit(buf, "%d\n", READ_ONCE(rcu_normal));
5a9be7c6 PM	222	}
	223	static ssize_t rcu_normal_store(struct kobject *kobj,
	224	struct kobj_attribute *attr,
	225	const char *buf, size_t count)
	226	{
	227	if (kstrtoint(buf, 0, &rcu_normal))
	228	return -EINVAL;
	229
	230	return count;
	231	}
	232	KERNEL_ATTR_RW(rcu_normal);
79cfea02	233	#endif /* #ifndef CONFIG_TINY_RCU */
5a9be7c6	234
da1a679c RM	235	/*
	236	* Make /sys/kernel/notes give the raw contents of our kernel .notes section.
	237	*/
377d9095 AB	238	extern const void __start_notes;
377d9095 AB	239	extern const void __stop_notes;
da1a679c RM	240	#define notes_size (&__stop_notes - &__start_notes)
da1a679c RM	241
0f9e1f3a	242	static __ro_after_init BIN_ATTR_SIMPLE_RO(notes);
da1a679c	243
0ff21e46 GKH	244	struct kobject *kernel_kobj;
0ff21e46 GKH	245	EXPORT_SYMBOL_GPL(kernel_kobj);
1da177e4 LT	246
1da177e4 LT	247	static struct attribute * kernel_attrs[] = {
088ab0b4	248	&fscaps_attr.attr,
0f76e5ac	249	&uevent_seqnum_attr.attr,
d3d76fbd	250	&cpu_byteorder_attr.attr,
00142bfd	251	&address_bits_attr.attr,
86d56134	252	#ifdef CONFIG_UEVENT_HELPER
0f76e5ac	253	&uevent_helper_attr.attr,
86d56134	254	#endif
22b8ce94 DH	255	#ifdef CONFIG_PROFILING
	256	&profiling_attr.attr,
	257	#endif
2965faa5	258	#ifdef CONFIG_KEXEC_CORE
c330dda9	259	&kexec_loaded_attr.attr,
02aff848	260	#ifdef CONFIG_CRASH_DUMP
c330dda9	261	&kexec_crash_loaded_attr.attr,
06a7f711	262	&kexec_crash_size_attr.attr,
692f66f2	263	#endif
02aff848	264	#endif
443cbaf9	265	#ifdef CONFIG_VMCORE_INFO
fd59d231	266	&vmcoreinfo_attr.attr,
a72bbec7 ED	267	#ifdef CONFIG_CRASH_HOTPLUG
	268	&crash_elfcorehdr_size_attr.attr,
	269	#endif
1da177e4	270	#endif
79cfea02	271	#ifndef CONFIG_TINY_RCU
3705b88d	272	&rcu_expedited_attr.attr,
5a9be7c6	273	&rcu_normal_attr.attr,
79cfea02	274	#endif
1da177e4 LT	275	NULL
	276	};
	277
9dcdcea1	278	static const struct attribute_group kernel_attr_group = {
1da177e4 LT	279	.attrs = kernel_attrs,
	280	};
	281
	282	static int __init ksysfs_init(void)
	283	{
bd35b93d	284	int error;
1da177e4	285
0ff21e46 GKH	286	kernel_kobj = kobject_create_and_add("kernel", NULL);
0ff21e46 GKH	287	if (!kernel_kobj) {
bd35b93d GKH	288	error = -ENOMEM;
	289	goto exit;
	290	}
0ff21e46	291	error = sysfs_create_group(kernel_kobj, &kernel_attr_group);
bd35b93d GKH	292	if (error)
	293	goto kset_exit;
	294
	295	if (notes_size > 0) {
0f9e1f3a TW	296	bin_attr_notes.private = (void *)&__start_notes;
	297	bin_attr_notes.size = notes_size;
	298	error = sysfs_create_bin_file(kernel_kobj, &bin_attr_notes);
bd35b93d GKH	299	if (error)
bd35b93d GKH	300	goto group_exit;
da1a679c RM	301	}
da1a679c RM	302
bd35b93d GKH	303	return 0;
bd35b93d GKH	304
bd35b93d	305	group_exit:
0ff21e46	306	sysfs_remove_group(kernel_kobj, &kernel_attr_group);
bd35b93d	307	kset_exit:
78a2d906	308	kobject_put(kernel_kobj);
bd35b93d	309	exit:
1da177e4 LT	310	return error;
	311	}
	312
	313	core_initcall(ksysfs_init);