1 files changed, 781 insertions, 0 deletions

diff --git a/drivers/firmware/efivars.c b/drivers/firmware/efivars.c
new file mode 100644
index 000000000000..0287ff65963b
--- /dev/null
+++ b/drivers/firmware/efivars.c
@@ -0,0 +1,781 @@
+/*
+ * EFI Variables - 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_unparse()
+ *
+ *  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/config.h>
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/sched.h>                /* for capable() */
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/smp.h>
+#include <linux/efi.h>
+#include <linux/sysfs.h>
+#include <linux/kobject.h>
+#include <linux/device.h>
+
+#include <asm/uaccess.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);
+
+/*
+ * efivars_lock protects two things:
+ * 1) efivar_list - adds, removals, reads, writes
+ * 2) efi.[gs]et_variable() calls.
+ * It must not be held when creating sysfs entries or calling kmalloc.
+ * efi.get_next_variable() is only called from efivars_init(),
+ * which is protected by the BKL, so that path is safe.
+ */
+static DEFINE_SPINLOCK(efivars_lock);
+static LIST_HEAD(efivar_list);
+
+/*
+ * The maximum size of VariableName + Data = 1024
+ * Therefore, it's reasonable to save that much
+ * space in each part of the structure,
+ * and we use a page for reading/writing.
+ */
+
+struct efi_variable {
+        efi_char16_t  VariableName[1024/sizeof(efi_char16_t)];
+        efi_guid_t    VendorGuid;
+        unsigned long DataSize;
+        __u8          Data[1024];
+        efi_status_t  Status;
+        __u32         Attributes;
+} __attribute__((packed));
+
+
+struct efivar_entry {
+        struct efi_variable var;
+        struct list_head list;
+        struct kobject kobj;
+};
+
+#define get_efivar_entry(n) list_entry(n, struct efivar_entry, list)
+
+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 EFI_ATTR(_name, _mode, _show, _store) \
+struct subsys_attribute efi_attr_##_name = { \
+        .attr = {.name = __stringify(_name), .mode = _mode, .owner = THIS_MODULE}, \
+        .show = _show, \
+        .store = _store, \
+};
+
+#define EFIVAR_ATTR(_name, _mode, _show, _store) \
+struct efivar_attribute efivar_attr_##_name = { \
+        .attr = {.name = __stringify(_name), .mode = _mode, .owner = THIS_MODULE}, \
+        .show = _show, \
+        .store = _store, \
+};
+
+#define VAR_SUBSYS_ATTR(_name, _mode, _show, _store) \
+struct subsys_attribute var_subsys_attr_##_name = { \
+        .attr = {.name = __stringify(_name), .mode = _mode, .owner = THIS_MODULE}, \
+        .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(unsigned long variable_name_size,
+                                efi_char16_t *variable_name,
+                                efi_guid_t *vendor_guid);
+
+/* Return the number of unicode characters in data */
+static unsigned long
+utf8_strlen(efi_char16_t *data, unsigned long maxlength)
+{
+        unsigned long length = 0;
+
+        while (*data++ != 0 && length < maxlength)
+                length++;
+        return length;
+}
+
+/*
+ * Return the number of bytes is the length of this string
+ * Note: this is NOT the same as the number of unicode characters
+ */
+static inline unsigned long
+utf8_strsize(efi_char16_t *data, unsigned long maxlength)
+{
+        return utf8_strlen(data, maxlength/sizeof(efi_char16_t)) * sizeof(efi_char16_t);
+}
+
+static efi_status_t
+get_var_data(struct efi_variable *var)
+{
+        efi_status_t status;
+
+        spin_lock(&efivars_lock);
+        var->DataSize = 1024;
+        status = efi.get_variable(var->VariableName,
+                                &var->VendorGuid,
+                                &var->Attributes,
+                                &var->DataSize,
+                                var->Data);
+        spin_unlock(&efivars_lock);
+        if (status != EFI_SUCCESS) {
+                printk(KERN_WARNING "efivars: get_variable() failed 0x%lx!\n",
+                        status);
+        }
+        return status;
+}
+
+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_unparse(&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;
+        efi_status_t status;
+
+        if (!entry || !buf)
+                return -EINVAL;
+
+        status = get_var_data(var);
+        if (status != EFI_SUCCESS)
+                return -EIO;
+
+        if (var->Attributes & 0x1)
+                str += sprintf(str, "EFI_VARIABLE_NON_VOLATILE\n");
+        if (var->Attributes & 0x2)
+                str += sprintf(str, "EFI_VARIABLE_BOOTSERVICE_ACCESS\n");
+        if (var->Attributes & 0x4)
+                str += sprintf(str, "EFI_VARIABLE_RUNTIME_ACCESS\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;
+        efi_status_t status;
+
+        if (!entry || !buf)
+                return -EINVAL;
+
+        status = get_var_data(var);
+        if (status != EFI_SUCCESS)
+                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;
+        efi_status_t status;
+
+        if (!entry || !buf)
+                return -EINVAL;
+
+        status = get_var_data(var);
+        if (status != EFI_SUCCESS)
+                return -EIO;
+
+        memcpy(buf, var->Data, var->DataSize);
+        return var->DataSize;
+}
+/*
+ * 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_status_t status = EFI_NOT_FOUND;
+
+        if (count != sizeof(struct efi_variable))
+                return -EINVAL;
+
+        new_var = (struct efi_variable *)buf;
+        /*
+         * If only updating the variable data, then the name
+         * and guid should remain the same
+         */
+        if (memcmp(new_var->VariableName, var->VariableName, sizeof(var->VariableName)) ||
+                efi_guidcmp(new_var->VendorGuid, var->VendorGuid)) {
+                printk(KERN_ERR "efivars: Cannot edit the wrong variable!\n");
+                return -EINVAL;
+        }
+
+        if ((new_var->DataSize <= 0) || (new_var->Attributes == 0)){
+                printk(KERN_ERR "efivars: DataSize & Attributes must be valid!\n");
+                return -EINVAL;
+        }
+
+        spin_lock(&efivars_lock);
+        status = efi.set_variable(new_var->VariableName,
+                                        &new_var->VendorGuid,
+                                        new_var->Attributes,
+                                        new_var->DataSize,
+                                        new_var->Data);
+
+        spin_unlock(&efivars_lock);
+
+        if (status != EFI_SUCCESS) {
+                printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
+                        status);
+                return -EIO;
+        }
+
+        memcpy(&entry->var, new_var, count);
+        return count;
+}
+
+static ssize_t
+efivar_show_raw(struct efivar_entry *entry, char *buf)
+{
+        struct efi_variable *var = &entry->var;
+        efi_status_t status;
+
+        if (!entry || !buf)
+                return 0;
+
+        status = get_var_data(var);
+        if (status != EFI_SUCCESS)
+                return -EIO;
+
+        memcpy(buf, var, sizeof(*var));
+        return sizeof(*var);
+}
+
+/*
+ * Generic read/write functions that call the specific functions of
+ * the atttributes...
+ */
+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 = 0;
+
+        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 = 0;
+
+        if (!capable(CAP_SYS_ADMIN))
+                return -EACCES;
+
+        if (efivar_attr->store)
+                ret = efivar_attr->store(var, buf, count);
+
+        return ret;
+}
+
+static 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);
+        spin_lock(&efivars_lock);
+        list_del(&var->list);
+        spin_unlock(&efivars_lock);
+        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 ktype_efivar = {
+        .release = efivar_release,
+        .sysfs_ops = &efivar_attr_ops,
+        .default_attrs = def_attrs,
+};
+
+static ssize_t
+dummy(struct subsystem *sub, char *buf)
+{
+        return -ENODEV;
+}
+
+static inline void
+efivar_unregister(struct efivar_entry *var)
+{
+        kobject_unregister(&var->kobj);
+}
+
+
+static ssize_t
+efivar_create(struct subsystem *sub, const char *buf, size_t count)
+{
+        struct efi_variable *new_var = (struct efi_variable *)buf;
+        struct efivar_entry *search_efivar = NULL;
+        unsigned long strsize1, strsize2;
+        struct list_head *pos, *n;
+        efi_status_t status = EFI_NOT_FOUND;
+        int found = 0;
+
+        if (!capable(CAP_SYS_ADMIN))
+                return -EACCES;
+
+        spin_lock(&efivars_lock);
+
+        /*
+         * Does this variable already exist?
+         */
+        list_for_each_safe(pos, n, &efivar_list) {
+                search_efivar = get_efivar_entry(pos);
+                strsize1 = utf8_strsize(search_efivar->var.VariableName, 1024);
+                strsize2 = utf8_strsize(new_var->VariableName, 1024);
+                if (strsize1 == strsize2 &&
+                        !memcmp(&(search_efivar->var.VariableName),
+                                new_var->VariableName, strsize1) &&
+                        !efi_guidcmp(search_efivar->var.VendorGuid,
+                                new_var->VendorGuid)) {
+                        found = 1;
+                        break;
+                }
+        }
+        if (found) {
+                spin_unlock(&efivars_lock);
+                return -EINVAL;
+        }
+
+        /* now *really* create the variable via EFI */
+        status = efi.set_variable(new_var->VariableName,
+                        &new_var->VendorGuid,
+                        new_var->Attributes,
+                        new_var->DataSize,
+                        new_var->Data);
+
+        if (status != EFI_SUCCESS) {
+                printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
+                        status);
+                spin_unlock(&efivars_lock);
+                return -EIO;
+        }
+        spin_unlock(&efivars_lock);
+
+        /* Create the entry in sysfs.  Locking is not required here */
+        status = efivar_create_sysfs_entry(utf8_strsize(new_var->VariableName,
+                        1024), new_var->VariableName, &new_var->VendorGuid);
+        if (status) {
+                printk(KERN_WARNING "efivars: variable created, but sysfs entry wasn't.\n");
+        }
+        return count;
+}
+
+static ssize_t
+efivar_delete(struct subsystem *sub, const char *buf, size_t count)
+{
+        struct efi_variable *del_var = (struct efi_variable *)buf;
+        struct efivar_entry *search_efivar = NULL;
+        unsigned long strsize1, strsize2;
+        struct list_head *pos, *n;
+        efi_status_t status = EFI_NOT_FOUND;
+        int found = 0;
+
+        if (!capable(CAP_SYS_ADMIN))
+                return -EACCES;
+
+        spin_lock(&efivars_lock);
+
+        /*
+         * Does this variable already exist?
+         */
+        list_for_each_safe(pos, n, &efivar_list) {
+                search_efivar = get_efivar_entry(pos);
+                strsize1 = utf8_strsize(search_efivar->var.VariableName, 1024);
+                strsize2 = utf8_strsize(del_var->VariableName, 1024);
+                if (strsize1 == strsize2 &&
+                        !memcmp(&(search_efivar->var.VariableName),
+                                del_var->VariableName, strsize1) &&
+                        !efi_guidcmp(search_efivar->var.VendorGuid,
+                                del_var->VendorGuid)) {
+                        found = 1;
+                        break;
+                }
+        }
+        if (!found) {
+                spin_unlock(&efivars_lock);
+                return -EINVAL;
+        }
+        /* force the Attributes/DataSize to 0 to ensure deletion */
+        del_var->Attributes = 0;
+        del_var->DataSize = 0;
+
+        status = efi.set_variable(del_var->VariableName,
+                        &del_var->VendorGuid,
+                        del_var->Attributes,
+                        del_var->DataSize,
+                        del_var->Data);
+
+        if (status != EFI_SUCCESS) {
+                printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
+                        status);
+                spin_unlock(&efivars_lock);
+                return -EIO;
+        }
+        /* We need to release this lock before unregistering. */
+        spin_unlock(&efivars_lock);
+
+        efivar_unregister(search_efivar);
+
+        /* It's dead Jim.... */
+        return count;
+}
+
+static VAR_SUBSYS_ATTR(new_var, 0200, dummy, efivar_create);
+static VAR_SUBSYS_ATTR(del_var, 0200, dummy, efivar_delete);
+
+static struct subsys_attribute *var_subsys_attrs[] = {
+        &var_subsys_attr_new_var,
+        &var_subsys_attr_del_var,
+        NULL,
+};
+
+/*
+ * Let's not leave out systab information that snuck into
+ * the efivars driver
+ */
+static ssize_t
+systab_read(struct subsystem *entry, char *buf)
+{
+        char *str = buf;
+
+        if (!entry || !buf)
+                return -EINVAL;
+
+        if (efi.mps)
+                str += sprintf(str, "MPS=0x%lx\n", __pa(efi.mps));
+        if (efi.acpi20)
+                str += sprintf(str, "ACPI20=0x%lx\n", __pa(efi.acpi20));
+        if (efi.acpi)
+                str += sprintf(str, "ACPI=0x%lx\n", __pa(efi.acpi));
+        if (efi.smbios)
+                str += sprintf(str, "SMBIOS=0x%lx\n", __pa(efi.smbios));
+        if (efi.hcdp)
+                str += sprintf(str, "HCDP=0x%lx\n", __pa(efi.hcdp));
+        if (efi.boot_info)
+                str += sprintf(str, "BOOTINFO=0x%lx\n", __pa(efi.boot_info));
+        if (efi.uga)
+                str += sprintf(str, "UGA=0x%lx\n", __pa(efi.uga));
+
+        return str - buf;
+}
+
+static EFI_ATTR(systab, 0400, systab_read, NULL);
+
+static struct subsys_attribute *efi_subsys_attrs[] = {
+        &efi_attr_systab,
+        NULL,   /* maybe more in the future? */
+};
+
+static decl_subsys(vars, &ktype_efivar, NULL);
+static decl_subsys(efi, NULL, NULL);
+
+/*
+ * efivar_create_sysfs_entry()
+ * Requires:
+ *    variable_name_size = number of bytes required to hold
+ *                         variable_name (not counting the NULL
+ *                         character at the end.
+ *    efivars_lock is not held on entry or exit.
+ * Returns 1 on failure, 0 on success
+ */
+static int
+efivar_create_sysfs_entry(unsigned long variable_name_size,
+                        efi_char16_t *variable_name,
+                        efi_guid_t *vendor_guid)
+{
+        int i, short_name_size = variable_name_size / sizeof(efi_char16_t) + 38;
+        char *short_name;
+        struct efivar_entry *new_efivar;
+
+        short_name = kmalloc(short_name_size + 1, GFP_KERNEL);
+        new_efivar = kmalloc(sizeof(struct efivar_entry), GFP_KERNEL);
+
+        if (!short_name || !new_efivar)  {
+                if (short_name)        kfree(short_name);
+                if (new_efivar)        kfree(new_efivar);
+                return 1;
+        }
+        memset(short_name, 0, short_name_size+1);
+        memset(new_efivar, 0, sizeof(struct efivar_entry));
+
+        memcpy(new_efivar->var.VariableName, variable_name,
+                variable_name_size);
+        memcpy(&(new_efivar->var.VendorGuid), vendor_guid, sizeof(efi_guid_t));
+
+        /* 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_unparse(vendor_guid, short_name + strlen(short_name));
+
+        kobject_set_name(&new_efivar->kobj, "%s", short_name);
+        kobj_set_kset_s(new_efivar, vars_subsys);
+        kobject_register(&new_efivar->kobj);
+
+        kfree(short_name); short_name = NULL;
+
+        spin_lock(&efivars_lock);
+        list_add(&new_efivar->list, &efivar_list);
+        spin_unlock(&efivars_lock);
+
+        return 0;
+}
+/*
+ * For now we register the efi subsystem with the firmware subsystem
+ * and the vars subsystem with the efi subsystem.  In the future, it
+ * might make sense to split off the efi subsystem into its own
+ * driver, but for now only efivars will register with it, so just
+ * include it here.
+ */
+
+static int __init
+efivars_init(void)
+{
+        efi_status_t status = EFI_NOT_FOUND;
+        efi_guid_t vendor_guid;
+        efi_char16_t *variable_name;
+        struct subsys_attribute *attr;
+        unsigned long variable_name_size = 1024;
+        int i, error = 0;
+
+        if (!efi_enabled)
+                return -ENODEV;
+
+        variable_name = kmalloc(variable_name_size, GFP_KERNEL);
+        if (!variable_name) {
+                printk(KERN_ERR "efivars: Memory allocation failed.\n");
+                return -ENOMEM;
+        }
+
+        memset(variable_name, 0, variable_name_size);
+
+        printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION,
+               EFIVARS_DATE);
+
+        /*
+         * For now we'll register the efi subsys within this driver
+         */
+
+        error = firmware_register(&efi_subsys);
+
+        if (error) {
+                printk(KERN_ERR "efivars: Firmware registration failed with error %d.\n", error);
+                goto out_free;
+        }
+
+        kset_set_kset_s(&vars_subsys, efi_subsys);
+
+        error = subsystem_register(&vars_subsys);
+
+        if (error) {
+                printk(KERN_ERR "efivars: Subsystem registration failed with error %d.\n", error);
+                goto out_firmware_unregister;
+        }
+
+        /*
+         * Per EFI spec, the maximum storage allocated for both
+         * the variable name and variable data is 1024 bytes.
+         */
+
+        do {
+                variable_name_size = 1024;
+
+                status = efi.get_next_variable(&variable_name_size,
+                                                variable_name,
+                                                &vendor_guid);
+                switch (status) {
+                case EFI_SUCCESS:
+                        efivar_create_sysfs_entry(variable_name_size,
+                                                        variable_name,
+                                                        &vendor_guid);
+                        break;
+                case EFI_NOT_FOUND:
+                        break;
+                default:
+                        printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n",
+                                status);
+                        status = EFI_NOT_FOUND;
+                        break;
+                }
+        } while (status != EFI_NOT_FOUND);
+
+        /*
+         * Now add attributes to allow creation of new vars
+         * and deletion of existing ones...
+         */
+
+        for (i = 0; (attr = var_subsys_attrs[i]) && !error; i++) {
+                if (attr->show && attr->store)
+                        error = subsys_create_file(&vars_subsys, attr);
+        }
+
+        /* Don't forget the systab entry */
+
+        for (i = 0; (attr = efi_subsys_attrs[i]) && !error; i++) {
+                if (attr->show)
+                        error = subsys_create_file(&efi_subsys, attr);
+        }
+
+        if (error)
+                printk(KERN_ERR "efivars: Sysfs attribute export failed with error %d.\n", error);
+        else
+                goto out_free;
+
+        subsystem_unregister(&vars_subsys);
+
+out_firmware_unregister:
+        firmware_unregister(&efi_subsys);
+
+out_free:
+        kfree(variable_name);
+
+        return error;
+}
+
+static void __exit
+efivars_exit(void)
+{
+        struct list_head *pos, *n;
+
+        list_for_each_safe(pos, n, &efivar_list)
+                efivar_unregister(get_efivar_entry(pos));
+
+        subsystem_unregister(&vars_subsys);
+        firmware_unregister(&efi_subsys);
+}
+
+module_init(efivars_init);
+module_exit(efivars_exit);
+