// 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/ksysfs.h>#include <linux/string.h>#include <linux/sysfs.h>#include <linux/export.h>#include <linux/init.h>#include <linux/vmcore_info.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_PROFILINGstatic 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_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); #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_RCUint 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_VMCORE_INFO	&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,}; void __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; group_exit:	sysfs_remove_group(kernel_kobj, &kernel_attr_group);kset_exit:	kobject_put(kernel_kobj);exit:	pr_err("failed to initialize the kernel kobject: %d\n", error);}