[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;

	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 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,
	&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) {
		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	{
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;
	95
	96	if (prof_on)
	97	return -EEXIST;
	98	/*
	99	* This eventually calls into get_option() which
	100	* has a ton of callers and is not const. It is
	101	* easiest to cast it away here.
	102	*/
	103	profile_setup((char *)buf);
	104	ret = profile_init();
	105	if (ret)
	106	return ret;
	107	ret = create_proc_profile();
	108	if (ret)
	109	return ret;
	110	return count;
	111	}
	112	KERNEL_ATTR_RW(profiling);
	113	#endif
	114
2965faa5	115	#ifdef CONFIG_KEXEC_CORE
386f275f KS	116	static ssize_t kexec_loaded_show(struct kobject *kobj,
386f275f KS	117	struct kobj_attribute attr, char buf)
c330dda9	118	{
9f33a88c	119	return sysfs_emit(buf, "%d\n", !!kexec_image);
c330dda9 JM	120	}
	121	KERNEL_ATTR_RO(kexec_loaded);
	122
02aff848	123	#ifdef CONFIG_CRASH_DUMP
386f275f KS	124	static ssize_t kexec_crash_loaded_show(struct kobject *kobj,
386f275f KS	125	struct kobj_attribute attr, char buf)
c330dda9	126	{
9f33a88c	127	return sysfs_emit(buf, "%d\n", kexec_crash_loaded());
c330dda9 JM	128	}
c330dda9 JM	129	KERNEL_ATTR_RO(kexec_crash_loaded);
fd59d231	130
06a7f711 AW	131	static ssize_t kexec_crash_size_show(struct kobject *kobj,
	132	struct kobj_attribute attr, char buf)
	133	{
7bb5da0d VS	134	ssize_t size = crash_get_memory_size();
	135
	136	if (size < 0)
	137	return size;
	138
9f33a88c	139	return sysfs_emit(buf, "%zd\n", size);
06a7f711 AW	140	}
	141	static ssize_t kexec_crash_size_store(struct kobject *kobj,
	142	struct kobj_attribute *attr,
	143	const char *buf, size_t count)
	144	{
	145	unsigned long cnt;
	146	int ret;
	147
6072ddc8	148	if (kstrtoul(buf, 0, &cnt))
06a7f711 AW	149	return -EINVAL;
	150
	151	ret = crash_shrink_memory(cnt);
	152	return ret < 0 ? ret : count;
	153	}
	154	KERNEL_ATTR_RW(kexec_crash_size);
	155
02aff848	156	#endif /* CONFIG_CRASH_DUMP*/
692f66f2 HB	157	#endif /* CONFIG_KEXEC_CORE */
692f66f2 HB	158
443cbaf9	159	#ifdef CONFIG_VMCORE_INFO
692f66f2	160
386f275f KS	161	static ssize_t vmcoreinfo_show(struct kobject *kobj,
386f275f KS	162	struct kobj_attribute attr, char buf)
fd59d231	163	{
dae28018	164	phys_addr_t vmcore_base = paddr_vmcoreinfo_note();
9f33a88c TW	165	return sysfs_emit(buf, "%pa %x\n", &vmcore_base,
9f33a88c TW	166	(unsigned int)VMCOREINFO_NOTE_SIZE);
fd59d231 KO	167	}
	168	KERNEL_ATTR_RO(vmcoreinfo);
	169
a72bbec7 ED	170	#ifdef CONFIG_CRASH_HOTPLUG
	171	static ssize_t crash_elfcorehdr_size_show(struct kobject *kobj,
	172	struct kobj_attribute attr, char buf)
	173	{
	174	unsigned int sz = crash_get_elfcorehdr_size();
	175
	176	return sysfs_emit(buf, "%u\n", sz);
	177	}
	178	KERNEL_ATTR_RO(crash_elfcorehdr_size);
	179
	180	#endif
	181
443cbaf9	182	#endif /* CONFIG_VMCORE_INFO */
c330dda9	183
088ab0b4 LN	184	/* whether file capabilities are enabled */
	185	static ssize_t fscaps_show(struct kobject *kobj,
	186	struct kobj_attribute attr, char buf)
	187	{
9f33a88c	188	return sysfs_emit(buf, "%d\n", file_caps_enabled);
088ab0b4 LN	189	}
	190	KERNEL_ATTR_RO(fscaps);
	191
79cfea02	192	#ifndef CONFIG_TINY_RCU
3705b88d AM	193	int rcu_expedited;
	194	static ssize_t rcu_expedited_show(struct kobject *kobj,
	195	struct kobj_attribute attr, char buf)
	196	{
9f33a88c	197	return sysfs_emit(buf, "%d\n", READ_ONCE(rcu_expedited));
3705b88d AM	198	}
	199	static ssize_t rcu_expedited_store(struct kobject *kobj,
	200	struct kobj_attribute *attr,
	201	const char *buf, size_t count)
	202	{
	203	if (kstrtoint(buf, 0, &rcu_expedited))
	204	return -EINVAL;
	205
	206	return count;
	207	}
	208	KERNEL_ATTR_RW(rcu_expedited);
	209
5a9be7c6 PM	210	int rcu_normal;
	211	static ssize_t rcu_normal_show(struct kobject *kobj,
	212	struct kobj_attribute attr, char buf)
	213	{
9f33a88c	214	return sysfs_emit(buf, "%d\n", READ_ONCE(rcu_normal));
5a9be7c6 PM	215	}
	216	static ssize_t rcu_normal_store(struct kobject *kobj,
	217	struct kobj_attribute *attr,
	218	const char *buf, size_t count)
	219	{
	220	if (kstrtoint(buf, 0, &rcu_normal))
	221	return -EINVAL;
	222
	223	return count;
	224	}
	225	KERNEL_ATTR_RW(rcu_normal);
79cfea02	226	#endif /* #ifndef CONFIG_TINY_RCU */
5a9be7c6	227
da1a679c RM	228	/*
	229	* Make /sys/kernel/notes give the raw contents of our kernel .notes section.
	230	*/
377d9095 AB	231	extern const void __start_notes;
377d9095 AB	232	extern const void __stop_notes;
da1a679c RM	233	#define notes_size (&__stop_notes - &__start_notes)
da1a679c RM	234
2c3c8bea CW	235	static ssize_t notes_read(struct file filp, struct kobject kobj,
2c3c8bea CW	236	struct bin_attribute *bin_attr,
da1a679c RM	237	char *buf, loff_t off, size_t count)
	238	{
	239	memcpy(buf, &__start_notes + off, count);
	240	return count;
	241	}
	242
738bc38d	243	static struct bin_attribute notes_attr __ro_after_init = {
da1a679c RM	244	.attr = {
	245	.name = "notes",
	246	.mode = S_IRUGO,
	247	},
	248	.read = &notes_read,
	249	};
	250
0ff21e46 GKH	251	struct kobject *kernel_kobj;
0ff21e46 GKH	252	EXPORT_SYMBOL_GPL(kernel_kobj);
1da177e4 LT	253
1da177e4 LT	254	static struct attribute * kernel_attrs[] = {
088ab0b4	255	&fscaps_attr.attr,
0f76e5ac	256	&uevent_seqnum_attr.attr,
d3d76fbd	257	&cpu_byteorder_attr.attr,
00142bfd	258	&address_bits_attr.attr,
86d56134	259	#ifdef CONFIG_UEVENT_HELPER
0f76e5ac	260	&uevent_helper_attr.attr,
86d56134	261	#endif
22b8ce94 DH	262	#ifdef CONFIG_PROFILING
	263	&profiling_attr.attr,
	264	#endif
2965faa5	265	#ifdef CONFIG_KEXEC_CORE
c330dda9	266	&kexec_loaded_attr.attr,
02aff848	267	#ifdef CONFIG_CRASH_DUMP
c330dda9	268	&kexec_crash_loaded_attr.attr,
06a7f711	269	&kexec_crash_size_attr.attr,
692f66f2	270	#endif
02aff848	271	#endif
443cbaf9	272	#ifdef CONFIG_VMCORE_INFO
fd59d231	273	&vmcoreinfo_attr.attr,
a72bbec7 ED	274	#ifdef CONFIG_CRASH_HOTPLUG
	275	&crash_elfcorehdr_size_attr.attr,
	276	#endif
1da177e4	277	#endif
79cfea02	278	#ifndef CONFIG_TINY_RCU
3705b88d	279	&rcu_expedited_attr.attr,
5a9be7c6	280	&rcu_normal_attr.attr,
79cfea02	281	#endif
1da177e4 LT	282	NULL
	283	};
	284
9dcdcea1	285	static const struct attribute_group kernel_attr_group = {
1da177e4 LT	286	.attrs = kernel_attrs,
	287	};
	288
	289	static int __init ksysfs_init(void)
	290	{
bd35b93d	291	int error;
1da177e4	292
0ff21e46 GKH	293	kernel_kobj = kobject_create_and_add("kernel", NULL);
0ff21e46 GKH	294	if (!kernel_kobj) {
bd35b93d GKH	295	error = -ENOMEM;
	296	goto exit;
	297	}
0ff21e46	298	error = sysfs_create_group(kernel_kobj, &kernel_attr_group);
bd35b93d GKH	299	if (error)
	300	goto kset_exit;
	301
	302	if (notes_size > 0) {
da1a679c	303	notes_attr.size = notes_size;
0ff21e46	304	error = sysfs_create_bin_file(kernel_kobj, &notes_attr);
bd35b93d GKH	305	if (error)
bd35b93d GKH	306	goto group_exit;
da1a679c RM	307	}
da1a679c RM	308
bd35b93d GKH	309	return 0;
bd35b93d GKH	310
bd35b93d	311	group_exit:
0ff21e46	312	sysfs_remove_group(kernel_kobj, &kernel_attr_group);
bd35b93d	313	kset_exit:
78a2d906	314	kobject_put(kernel_kobj);
bd35b93d	315	exit:
1da177e4 LT	316	return error;
	317	}
	318
	319	core_initcall(ksysfs_init);