Initial import

1 files changed, 755 insertions, 0 deletions

diff --git a/drivers/firmware/efi/efivars.c b/drivers/firmware/efi/efivars.c
new file mode 100644
index 000000000..7b2e0496e
--- /dev/null
+++ b/drivers/firmware/efi/efivars.c
@@ -0,0 +1,755 @@
+/*
+ * Originally from efivars.c,
+ *
+ * Copyright (C) 2001,2003,2004 Dell <Matt_Domsch@dell.com>
+ * Copyright (C) 2004 Intel Corporation <matthew.e.tolentino@intel.com>
+ *
+ * This code takes all variables accessible from EFI runtime and
+ *  exports them via sysfs
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ * Changelog:
+ *
+ *  17 May 2004 - Matt Domsch <Matt_Domsch@dell.com>
+ *   remove check for efi_enabled in exit
+ *   add MODULE_VERSION
+ *
+ *  26 Apr 2004 - Matt Domsch <Matt_Domsch@dell.com>
+ *   minor bug fixes
+ *
+ *  21 Apr 2004 - Matt Tolentino <matthew.e.tolentino@intel.com)
+ *   converted driver to export variable information via sysfs
+ *   and moved to drivers/firmware directory
+ *   bumped revision number to v0.07 to reflect conversion & move
+ *
+ *  10 Dec 2002 - Matt Domsch <Matt_Domsch@dell.com>
+ *   fix locking per Peter Chubb's findings
+ *
+ *  25 Mar 2002 - Matt Domsch <Matt_Domsch@dell.com>
+ *   move uuid_unparse() to include/asm-ia64/efi.h:efi_guid_to_str()
+ *
+ *  12 Feb 2002 - Matt Domsch <Matt_Domsch@dell.com>
+ *   use list_for_each_safe when deleting vars.
+ *   remove ifdef CONFIG_SMP around include <linux/smp.h>
+ *   v0.04 release to linux-ia64@linuxia64.org
+ *
+ *  20 April 2001 - Matt Domsch <Matt_Domsch@dell.com>
+ *   Moved vars from /proc/efi to /proc/efi/vars, and made
+ *   efi.c own the /proc/efi directory.
+ *   v0.03 release to linux-ia64@linuxia64.org
+ *
+ *  26 March 2001 - Matt Domsch <Matt_Domsch@dell.com>
+ *   At the request of Stephane, moved ownership of /proc/efi
+ *   to efi.c, and now efivars lives under /proc/efi/vars.
+ *
+ *  12 March 2001 - Matt Domsch <Matt_Domsch@dell.com>
+ *   Feedback received from Stephane Eranian incorporated.
+ *   efivar_write() checks copy_from_user() return value.
+ *   efivar_read/write() returns proper errno.
+ *   v0.02 release to linux-ia64@linuxia64.org
+ *
+ *  26 February 2001 - Matt Domsch <Matt_Domsch@dell.com>
+ *   v0.01 release to linux-ia64@linuxia64.org
+ */
+
+#include <linux/efi.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/ucs2_string.h>
+#include <linux/compat.h>
+
+#define EFIVARS_VERSION "0.08"
+#define EFIVARS_DATE "2004-May-17"
+
+MODULE_AUTHOR("Matt Domsch <Matt_Domsch@Dell.com>");
+MODULE_DESCRIPTION("sysfs interface to EFI Variables");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(EFIVARS_VERSION);
+MODULE_ALIAS("platform:efivars");
+
+LIST_HEAD(efivar_sysfs_list);
+EXPORT_SYMBOL_GPL(efivar_sysfs_list);
+
+static struct kset *efivars_kset;
+
+static struct bin_attribute *efivars_new_var;
+static struct bin_attribute *efivars_del_var;
+
+struct compat_efi_variable {
+	efi_char16_t  VariableName[EFI_VAR_NAME_LEN/sizeof(efi_char16_t)];
+	efi_guid_t    VendorGuid;
+	__u32         DataSize;
+	__u8          Data[1024];
+	__u32         Status;
+	__u32         Attributes;
+} __packed;
+
+struct efivar_attribute {
+	struct attribute attr;
+	ssize_t (*show) (struct efivar_entry *entry, char *buf);
+	ssize_t (*store)(struct efivar_entry *entry, const char *buf, size_t count);
+};
+
+#define EFIVAR_ATTR(_name, _mode, _show, _store) \
+struct efivar_attribute efivar_attr_##_name = { \
+	.attr = {.name = __stringify(_name), .mode = _mode}, \
+	.show = _show, \
+	.store = _store, \
+};
+
+#define to_efivar_attr(_attr) container_of(_attr, struct efivar_attribute, attr)
+#define to_efivar_entry(obj)  container_of(obj, struct efivar_entry, kobj)
+
+/*
+ * Prototype for sysfs creation function
+ */
+static int
+efivar_create_sysfs_entry(struct efivar_entry *new_var);
+
+static ssize_t
+efivar_guid_read(struct efivar_entry *entry, char *buf)
+{
+	struct efi_variable *var = &entry->var;
+	char *str = buf;
+
+	if (!entry || !buf)
+		return 0;
+
+	efi_guid_to_str(&var->VendorGuid, str);
+	str += strlen(str);
+	str += sprintf(str, "\n");
+
+	return str - buf;
+}
+
+static ssize_t
+efivar_attr_read(struct efivar_entry *entry, char *buf)
+{
+	struct efi_variable *var = &entry->var;
+	char *str = buf;
+
+	if (!entry || !buf)
+		return -EINVAL;
+
+	var->DataSize = 1024;
+	if (efivar_entry_get(entry, &var->Attributes, &var->DataSize, var->Data))
+		return -EIO;
+
+	if (var->Attributes & EFI_VARIABLE_NON_VOLATILE)
+		str += sprintf(str, "EFI_VARIABLE_NON_VOLATILE\n");
+	if (var->Attributes & EFI_VARIABLE_BOOTSERVICE_ACCESS)
+		str += sprintf(str, "EFI_VARIABLE_BOOTSERVICE_ACCESS\n");
+	if (var->Attributes & EFI_VARIABLE_RUNTIME_ACCESS)
+		str += sprintf(str, "EFI_VARIABLE_RUNTIME_ACCESS\n");
+	if (var->Attributes & EFI_VARIABLE_HARDWARE_ERROR_RECORD)
+		str += sprintf(str, "EFI_VARIABLE_HARDWARE_ERROR_RECORD\n");
+	if (var->Attributes & EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS)
+		str += sprintf(str,
+			"EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS\n");
+	if (var->Attributes &
+			EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS)
+		str += sprintf(str,
+			"EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS\n");
+	if (var->Attributes & EFI_VARIABLE_APPEND_WRITE)
+		str += sprintf(str, "EFI_VARIABLE_APPEND_WRITE\n");
+	return str - buf;
+}
+
+static ssize_t
+efivar_size_read(struct efivar_entry *entry, char *buf)
+{
+	struct efi_variable *var = &entry->var;
+	char *str = buf;
+
+	if (!entry || !buf)
+		return -EINVAL;
+
+	var->DataSize = 1024;
+	if (efivar_entry_get(entry, &var->Attributes, &var->DataSize, var->Data))
+		return -EIO;
+
+	str += sprintf(str, "0x%lx\n", var->DataSize);
+	return str - buf;
+}
+
+static ssize_t
+efivar_data_read(struct efivar_entry *entry, char *buf)
+{
+	struct efi_variable *var = &entry->var;
+
+	if (!entry || !buf)
+		return -EINVAL;
+
+	var->DataSize = 1024;
+	if (efivar_entry_get(entry, &var->Attributes, &var->DataSize, var->Data))
+		return -EIO;
+
+	memcpy(buf, var->Data, var->DataSize);
+	return var->DataSize;
+}
+
+static inline int
+sanity_check(struct efi_variable *var, efi_char16_t *name, efi_guid_t vendor,
+	     unsigned long size, u32 attributes, u8 *data)
+{
+	/*
+	 * If only updating the variable data, then the name
+	 * and guid should remain the same
+	 */
+	if (memcmp(name, var->VariableName, sizeof(var->VariableName)) ||
+		efi_guidcmp(vendor, var->VendorGuid)) {
+		printk(KERN_ERR "efivars: Cannot edit the wrong variable!\n");
+		return -EINVAL;
+	}
+
+	if ((size <= 0) || (attributes == 0)){
+		printk(KERN_ERR "efivars: DataSize & Attributes must be valid!\n");
+		return -EINVAL;
+	}
+
+	if ((attributes & ~EFI_VARIABLE_MASK) != 0 ||
+	    efivar_validate(name, data, size) == false) {
+		printk(KERN_ERR "efivars: Malformed variable content\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static inline bool is_compat(void)
+{
+	if (IS_ENABLED(CONFIG_COMPAT) && is_compat_task())
+		return true;
+
+	return false;
+}
+
+static void
+copy_out_compat(struct efi_variable *dst, struct compat_efi_variable *src)
+{
+	memcpy(dst->VariableName, src->VariableName, EFI_VAR_NAME_LEN);
+	memcpy(dst->Data, src->Data, sizeof(src->Data));
+
+	dst->VendorGuid = src->VendorGuid;
+	dst->DataSize = src->DataSize;
+	dst->Attributes = src->Attributes;
+}
+
+/*
+ * We allow each variable to be edited via rewriting the
+ * entire efi variable structure.
+ */
+static ssize_t
+efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count)
+{
+	struct efi_variable *new_var, *var = &entry->var;
+	efi_char16_t *name;
+	unsigned long size;
+	efi_guid_t vendor;
+	u32 attributes;
+	u8 *data;
+	int err;
+
+	if (is_compat()) {
+		struct compat_efi_variable *compat;
+
+		if (count != sizeof(*compat))
+			return -EINVAL;
+
+		compat = (struct compat_efi_variable *)buf;
+		attributes = compat->Attributes;
+		vendor = compat->VendorGuid;
+		name = compat->VariableName;
+		size = compat->DataSize;
+		data = compat->Data;
+
+		err = sanity_check(var, name, vendor, size, attributes, data);
+		if (err)
+			return err;
+
+		copy_out_compat(&entry->var, compat);
+	} else {
+		if (count != sizeof(struct efi_variable))
+			return -EINVAL;
+
+		new_var = (struct efi_variable *)buf;
+
+		attributes = new_var->Attributes;
+		vendor = new_var->VendorGuid;
+		name = new_var->VariableName;
+		size = new_var->DataSize;
+		data = new_var->Data;
+
+		err = sanity_check(var, name, vendor, size, attributes, data);
+		if (err)
+			return err;
+
+		memcpy(&entry->var, new_var, count);
+	}
+
+	err = efivar_entry_set(entry, attributes, size, data, NULL);
+	if (err) {
+		printk(KERN_WARNING "efivars: set_variable() failed: status=%d\n", err);
+		return -EIO;
+	}
+
+	return count;
+}
+
+static ssize_t
+efivar_show_raw(struct efivar_entry *entry, char *buf)
+{
+	struct efi_variable *var = &entry->var;
+	struct compat_efi_variable *compat;
+	size_t size;
+
+	if (!entry || !buf)
+		return 0;
+
+	var->DataSize = 1024;
+	if (efivar_entry_get(entry, &entry->var.Attributes,
+			     &entry->var.DataSize, entry->var.Data))
+		return -EIO;
+
+	if (is_compat()) {
+		compat = (struct compat_efi_variable *)buf;
+
+		size = sizeof(*compat);
+		memcpy(compat->VariableName, var->VariableName,
+			EFI_VAR_NAME_LEN);
+		memcpy(compat->Data, var->Data, sizeof(compat->Data));
+
+		compat->VendorGuid = var->VendorGuid;
+		compat->DataSize = var->DataSize;
+		compat->Attributes = var->Attributes;
+	} else {
+		size = sizeof(*var);
+		memcpy(buf, var, size);
+	}
+
+	return size;
+}
+
+/*
+ * Generic read/write functions that call the specific functions of
+ * the attributes...
+ */
+static ssize_t efivar_attr_show(struct kobject *kobj, struct attribute *attr,
+				char *buf)
+{
+	struct efivar_entry *var = to_efivar_entry(kobj);
+	struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
+	ssize_t ret = -EIO;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EACCES;
+
+	if (efivar_attr->show) {
+		ret = efivar_attr->show(var, buf);
+	}
+	return ret;
+}
+
+static ssize_t efivar_attr_store(struct kobject *kobj, struct attribute *attr,
+				const char *buf, size_t count)
+{
+	struct efivar_entry *var = to_efivar_entry(kobj);
+	struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
+	ssize_t ret = -EIO;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EACCES;
+
+	if (efivar_attr->store)
+		ret = efivar_attr->store(var, buf, count);
+
+	return ret;
+}
+
+static const struct sysfs_ops efivar_attr_ops = {
+	.show = efivar_attr_show,
+	.store = efivar_attr_store,
+};
+
+static void efivar_release(struct kobject *kobj)
+{
+	struct efivar_entry *var = container_of(kobj, struct efivar_entry, kobj);
+	kfree(var);
+}
+
+static EFIVAR_ATTR(guid, 0400, efivar_guid_read, NULL);
+static EFIVAR_ATTR(attributes, 0400, efivar_attr_read, NULL);
+static EFIVAR_ATTR(size, 0400, efivar_size_read, NULL);
+static EFIVAR_ATTR(data, 0400, efivar_data_read, NULL);
+static EFIVAR_ATTR(raw_var, 0600, efivar_show_raw, efivar_store_raw);
+
+static struct attribute *def_attrs[] = {
+	&efivar_attr_guid.attr,
+	&efivar_attr_size.attr,
+	&efivar_attr_attributes.attr,
+	&efivar_attr_data.attr,
+	&efivar_attr_raw_var.attr,
+	NULL,
+};
+
+static struct kobj_type efivar_ktype = {
+	.release = efivar_release,
+	.sysfs_ops = &efivar_attr_ops,
+	.default_attrs = def_attrs,
+};
+
+static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
+			     struct bin_attribute *bin_attr,
+			     char *buf, loff_t pos, size_t count)
+{
+	struct compat_efi_variable *compat = (struct compat_efi_variable *)buf;
+	struct efi_variable *new_var = (struct efi_variable *)buf;
+	struct efivar_entry *new_entry;
+	bool need_compat = is_compat();
+	efi_char16_t *name;
+	unsigned long size;
+	u32 attributes;
+	u8 *data;
+	int err;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EACCES;
+
+	if (need_compat) {
+		if (count != sizeof(*compat))
+			return -EINVAL;
+
+		attributes = compat->Attributes;
+		name = compat->VariableName;
+		size = compat->DataSize;
+		data = compat->Data;
+	} else {
+		if (count != sizeof(*new_var))
+			return -EINVAL;
+
+		attributes = new_var->Attributes;
+		name = new_var->VariableName;
+		size = new_var->DataSize;
+		data = new_var->Data;
+	}
+
+	if ((attributes & ~EFI_VARIABLE_MASK) != 0 ||
+	    efivar_validate(name, data, size) == false) {
+		printk(KERN_ERR "efivars: Malformed variable content\n");
+		return -EINVAL;
+	}
+
+	new_entry = kzalloc(sizeof(*new_entry), GFP_KERNEL);
+	if (!new_entry)
+		return -ENOMEM;
+
+	if (need_compat)
+		copy_out_compat(&new_entry->var, compat);
+	else
+		memcpy(&new_entry->var, new_var, sizeof(*new_var));
+
+	err = efivar_entry_set(new_entry, attributes, size,
+			       data, &efivar_sysfs_list);
+	if (err) {
+		if (err == -EEXIST)
+			err = -EINVAL;
+		goto out;
+	}
+
+	if (efivar_create_sysfs_entry(new_entry)) {
+		printk(KERN_WARNING "efivars: failed to create sysfs entry.\n");
+		kfree(new_entry);
+	}
+	return count;
+
+out:
+	kfree(new_entry);
+	return err;
+}
+
+static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
+			     struct bin_attribute *bin_attr,
+			     char *buf, loff_t pos, size_t count)
+{
+	struct efi_variable *del_var = (struct efi_variable *)buf;
+	struct compat_efi_variable *compat;
+	struct efivar_entry *entry;
+	efi_char16_t *name;
+	efi_guid_t vendor;
+	int err = 0;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EACCES;
+
+	if (is_compat()) {
+		if (count != sizeof(*compat))
+			return -EINVAL;
+
+		compat = (struct compat_efi_variable *)buf;
+		name = compat->VariableName;
+		vendor = compat->VendorGuid;
+	} else {
+		if (count != sizeof(*del_var))
+			return -EINVAL;
+
+		name = del_var->VariableName;
+		vendor = del_var->VendorGuid;
+	}
+
+	efivar_entry_iter_begin();
+	entry = efivar_entry_find(name, vendor, &efivar_sysfs_list, true);
+	if (!entry)
+		err = -EINVAL;
+	else if (__efivar_entry_delete(entry))
+		err = -EIO;
+
+	if (err) {
+		efivar_entry_iter_end();
+		return err;
+	}
+
+	if (!entry->scanning) {
+		efivar_entry_iter_end();
+		efivar_unregister(entry);
+	} else
+		efivar_entry_iter_end();
+
+	/* It's dead Jim.... */
+	return count;
+}
+
+/**
+ * efivar_create_sysfs_entry - create a new entry in sysfs
+ * @new_var: efivar entry to create
+ *
+ * Returns 1 on failure, 0 on success
+ */
+static int
+efivar_create_sysfs_entry(struct efivar_entry *new_var)
+{
+	int i, short_name_size;
+	char *short_name;
+	unsigned long variable_name_size;
+	efi_char16_t *variable_name;
+
+	variable_name = new_var->var.VariableName;
+	variable_name_size = ucs2_strlen(variable_name) * sizeof(efi_char16_t);
+
+	/*
+	 * Length of the variable bytes in ASCII, plus the '-' separator,
+	 * plus the GUID, plus trailing NUL
+	 */
+	short_name_size = variable_name_size / sizeof(efi_char16_t)
+				+ 1 + EFI_VARIABLE_GUID_LEN + 1;
+
+	short_name = kzalloc(short_name_size, GFP_KERNEL);
+
+	if (!short_name)
+		return 1;
+
+	/* Convert Unicode to normal chars (assume top bits are 0),
+	   ala UTF-8 */
+	for (i=0; i < (int)(variable_name_size / sizeof(efi_char16_t)); i++) {
+		short_name[i] = variable_name[i] & 0xFF;
+	}
+	/* This is ugly, but necessary to separate one vendor's
+	   private variables from another's.         */
+
+	*(short_name + strlen(short_name)) = '-';
+	efi_guid_to_str(&new_var->var.VendorGuid,
+			 short_name + strlen(short_name));
+
+	new_var->kobj.kset = efivars_kset;
+
+	i = kobject_init_and_add(&new_var->kobj, &efivar_ktype,
+				   NULL, "%s", short_name);
+	kfree(short_name);
+	if (i)
+		return 1;
+
+	kobject_uevent(&new_var->kobj, KOBJ_ADD);
+	efivar_entry_add(new_var, &efivar_sysfs_list);
+
+	return 0;
+}
+
+static int
+create_efivars_bin_attributes(void)
+{
+	struct bin_attribute *attr;
+	int error;
+
+	/* new_var */
+	attr = kzalloc(sizeof(*attr), GFP_KERNEL);
+	if (!attr)
+		return -ENOMEM;
+
+	attr->attr.name = "new_var";
+	attr->attr.mode = 0200;
+	attr->write = efivar_create;
+	efivars_new_var = attr;
+
+	/* del_var */
+	attr = kzalloc(sizeof(*attr), GFP_KERNEL);
+	if (!attr) {
+		error = -ENOMEM;
+		goto out_free;
+	}
+	attr->attr.name = "del_var";
+	attr->attr.mode = 0200;
+	attr->write = efivar_delete;
+	efivars_del_var = attr;
+
+	sysfs_bin_attr_init(efivars_new_var);
+	sysfs_bin_attr_init(efivars_del_var);
+
+	/* Register */
+	error = sysfs_create_bin_file(&efivars_kset->kobj, efivars_new_var);
+	if (error) {
+		printk(KERN_ERR "efivars: unable to create new_var sysfs file"
+			" due to error %d\n", error);
+		goto out_free;
+	}
+
+	error = sysfs_create_bin_file(&efivars_kset->kobj, efivars_del_var);
+	if (error) {
+		printk(KERN_ERR "efivars: unable to create del_var sysfs file"
+			" due to error %d\n", error);
+		sysfs_remove_bin_file(&efivars_kset->kobj, efivars_new_var);
+		goto out_free;
+	}
+
+	return 0;
+out_free:
+	kfree(efivars_del_var);
+	efivars_del_var = NULL;
+	kfree(efivars_new_var);
+	efivars_new_var = NULL;
+	return error;
+}
+
+static int efivar_update_sysfs_entry(efi_char16_t *name, efi_guid_t vendor,
+				     unsigned long name_size, void *data)
+{
+	struct efivar_entry *entry = data;
+
+	if (efivar_entry_find(name, vendor, &efivar_sysfs_list, false))
+		return 0;
+
+	memcpy(entry->var.VariableName, name, name_size);
+	memcpy(&(entry->var.VendorGuid), &vendor, sizeof(efi_guid_t));
+
+	return 1;
+}
+
+static void efivar_update_sysfs_entries(struct work_struct *work)
+{
+	struct efivar_entry *entry;
+	int err;
+
+	/* Add new sysfs entries */
+	while (1) {
+		entry = kzalloc(sizeof(*entry), GFP_KERNEL);
+		if (!entry)
+			return;
+
+		err = efivar_init(efivar_update_sysfs_entry, entry,
+				  true, false, &efivar_sysfs_list);
+		if (!err)
+			break;
+
+		efivar_create_sysfs_entry(entry);
+	}
+
+	kfree(entry);
+}
+
+static int efivars_sysfs_callback(efi_char16_t *name, efi_guid_t vendor,
+				  unsigned long name_size, void *data)
+{
+	struct efivar_entry *entry;
+
+	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
+	if (!entry)
+		return -ENOMEM;
+
+	memcpy(entry->var.VariableName, name, name_size);
+	memcpy(&(entry->var.VendorGuid), &vendor, sizeof(efi_guid_t));
+
+	efivar_create_sysfs_entry(entry);
+
+	return 0;
+}
+
+static int efivar_sysfs_destroy(struct efivar_entry *entry, void *data)
+{
+	efivar_entry_remove(entry);
+	efivar_unregister(entry);
+	return 0;
+}
+
+static void efivars_sysfs_exit(void)
+{
+	/* Remove all entries and destroy */
+	__efivar_entry_iter(efivar_sysfs_destroy, &efivar_sysfs_list, NULL, NULL);
+
+	if (efivars_new_var)
+		sysfs_remove_bin_file(&efivars_kset->kobj, efivars_new_var);
+	if (efivars_del_var)
+		sysfs_remove_bin_file(&efivars_kset->kobj, efivars_del_var);
+	kfree(efivars_new_var);
+	kfree(efivars_del_var);
+	kset_unregister(efivars_kset);
+}
+
+int efivars_sysfs_init(void)
+{
+	struct kobject *parent_kobj = efivars_kobject();
+	int error = 0;
+
+	if (!efi_enabled(EFI_RUNTIME_SERVICES))
+		return -ENODEV;
+
+	/* No efivars has been registered yet */
+	if (!parent_kobj)
+		return 0;
+
+	printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION,
+	       EFIVARS_DATE);
+
+	efivars_kset = kset_create_and_add("vars", NULL, parent_kobj);
+	if (!efivars_kset) {
+		printk(KERN_ERR "efivars: Subsystem registration failed.\n");
+		return -ENOMEM;
+	}
+
+	efivar_init(efivars_sysfs_callback, NULL, false,
+		    true, &efivar_sysfs_list);
+
+	error = create_efivars_bin_attributes();
+	if (error) {
+		efivars_sysfs_exit();
+		return error;
+	}
+
+	INIT_WORK(&efivar_work, efivar_update_sysfs_entries);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(efivars_sysfs_init);
+
+module_init(efivars_sysfs_init);
+module_exit(efivars_sysfs_exit);