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alistair23-linux/drivers/firmware/efivars.c

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/*
* 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/capability.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/init.h>
#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 <linux/slab.h>
#include <linux/pstore.h>
#include <linux/ctype.h>
#include <linux/fs.h>
#include <linux/ramfs.h>
#include <linux/pagemap.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);
#define DUMP_NAME_LEN 52
static LIST_HEAD(efivarfs_list);
static LIST_HEAD(efivar_sysfs_list);
static bool efivars_pstore_disable =
IS_ENABLED(CONFIG_EFI_VARS_PSTORE_DEFAULT_DISABLE);
module_param_named(pstore_disable, efivars_pstore_disable, bool, 0644);
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);
};
/* Private pointer to registered efivars */
static struct efivars *__efivars;
#define PSTORE_EFI_ATTRIBUTES \
(EFI_VARIABLE_NON_VOLATILE | \
EFI_VARIABLE_BOOTSERVICE_ACCESS | \
EFI_VARIABLE_RUNTIME_ACCESS)
static struct kset *efivars_kset;
static struct bin_attribute *efivars_new_var;
static struct bin_attribute *efivars_del_var;
#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);
/*
* Prototype for workqueue functions updating sysfs entry
*/
static void efivar_update_sysfs_entries(struct work_struct *);
static DECLARE_WORK(efivar_work, efivar_update_sysfs_entries);
static bool efivar_wq_enabled = true;
/*
* 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
utf16_strsize(efi_char16_t *data, unsigned long maxlength)
{
return utf16_strnlen(data, maxlength/sizeof(efi_char16_t)) * sizeof(efi_char16_t);
}
static inline int
utf16_strncmp(const efi_char16_t *a, const efi_char16_t *b, size_t len)
{
while (1) {
if (len == 0)
return 0;
if (*a < *b)
return -1;
if (*a > *b)
return 1;
if (*a == 0) /* implies *b == 0 */
return 0;
a++;
b++;
len--;
}
}
static bool
validate_device_path(struct efi_variable *var, int match, u8 *buffer,
unsigned long len)
{
struct efi_generic_dev_path *node;
int offset = 0;
node = (struct efi_generic_dev_path *)buffer;
if (len < sizeof(*node))
return false;
while (offset <= len - sizeof(*node) &&
node->length >= sizeof(*node) &&
node->length <= len - offset) {
offset += node->length;
if ((node->type == EFI_DEV_END_PATH ||
node->type == EFI_DEV_END_PATH2) &&
node->sub_type == EFI_DEV_END_ENTIRE)
return true;
node = (struct efi_generic_dev_path *)(buffer + offset);
}
/*
* If we're here then either node->length pointed past the end
* of the buffer or we reached the end of the buffer without
* finding a device path end node.
*/
return false;
}
static bool
validate_boot_order(struct efi_variable *var, int match, u8 *buffer,
unsigned long len)
{
/* An array of 16-bit integers */
if ((len % 2) != 0)
return false;
return true;
}
static bool
validate_load_option(struct efi_variable *var, int match, u8 *buffer,
unsigned long len)
{
u16 filepathlength;
int i, desclength = 0, namelen;
namelen = utf16_strnlen(var->VariableName, sizeof(var->VariableName));
/* Either "Boot" or "Driver" followed by four digits of hex */
for (i = match; i < match+4; i++) {
if (var->VariableName[i] > 127 ||
hex_to_bin(var->VariableName[i] & 0xff) < 0)
return true;
}
/* Reject it if there's 4 digits of hex and then further content */
if (namelen > match + 4)
return false;
/* A valid entry must be at least 8 bytes */
if (len < 8)
return false;
filepathlength = buffer[4] | buffer[5] << 8;
/*
* There's no stored length for the description, so it has to be
* found by hand
*/
desclength = utf16_strsize((efi_char16_t *)(buffer + 6), len - 6) + 2;
/* Each boot entry must have a descriptor */
if (!desclength)
return false;
/*
* If the sum of the length of the description, the claimed filepath
* length and the original header are greater than the length of the
* variable, it's malformed
*/
if ((desclength + filepathlength + 6) > len)
return false;
/*
* And, finally, check the filepath
*/
return validate_device_path(var, match, buffer + desclength + 6,
filepathlength);
}
static bool
validate_uint16(struct efi_variable *var, int match, u8 *buffer,
unsigned long len)
{
/* A single 16-bit integer */
if (len != 2)
return false;
return true;
}
static bool
validate_ascii_string(struct efi_variable *var, int match, u8 *buffer,
unsigned long len)
{
int i;
for (i = 0; i < len; i++) {
if (buffer[i] > 127)
return false;
if (buffer[i] == 0)
return true;
}
return false;
}
struct variable_validate {
char *name;
bool (*validate)(struct efi_variable *var, int match, u8 *data,
unsigned long len);
};
static const struct variable_validate variable_validate[] = {
{ "BootNext", validate_uint16 },
{ "BootOrder", validate_boot_order },
{ "DriverOrder", validate_boot_order },
{ "Boot*", validate_load_option },
{ "Driver*", validate_load_option },
{ "ConIn", validate_device_path },
{ "ConInDev", validate_device_path },
{ "ConOut", validate_device_path },
{ "ConOutDev", validate_device_path },
{ "ErrOut", validate_device_path },
{ "ErrOutDev", validate_device_path },
{ "Timeout", validate_uint16 },
{ "Lang", validate_ascii_string },
{ "PlatformLang", validate_ascii_string },
{ "", NULL },
};
bool
efivar_validate(struct efi_variable *var, u8 *data, unsigned long len)
{
int i;
u16 *unicode_name = var->VariableName;
for (i = 0; variable_validate[i].validate != NULL; i++) {
const char *name = variable_validate[i].name;
int match;
for (match = 0; ; match++) {
char c = name[match];
u16 u = unicode_name[match];
/* All special variables are plain ascii */
if (u > 127)
return true;
/* Wildcard in the matching name means we've matched */
if (c == '*')
return variable_validate[i].validate(var,
match, data, len);
/* Case sensitive match */
if (c != u)
break;
/* Reached the end of the string while matching */
if (!c)
return variable_validate[i].validate(var,
match, data, len);
}
}
return true;
}
EXPORT_SYMBOL_GPL(efivar_validate);
static efi_status_t
check_var_size(u32 attributes, unsigned long size)
{
u64 storage_size, remaining_size, max_size;
efi_status_t status;
const struct efivar_operations *fops = __efivars->ops;
if (!fops->query_variable_info)
return EFI_UNSUPPORTED;
status = fops->query_variable_info(attributes, &storage_size,
&remaining_size, &max_size);
if (status != EFI_SUCCESS)
return status;
if (!storage_size || size > remaining_size || size > max_size ||
(remaining_size - size) < (storage_size / 2))
return EFI_OUT_OF_RESOURCES;
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;
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;
}
/*
* 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;
int err;
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;
}
if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
efivar_validate(new_var, new_var->Data, new_var->DataSize) == false) {
printk(KERN_ERR "efivars: Malformed variable content\n");
return -EINVAL;
}
memcpy(&entry->var, new_var, count);
err = efivar_entry_set(entry, new_var->Attributes,
new_var->DataSize, new_var->Data, false);
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;
if (!entry || !buf)
return 0;
var->DataSize = 1024;
if (efivar_entry_get(entry, &entry->var.Attributes,
&entry->var.DataSize, entry->var.Data))
return -EIO;
memcpy(buf, var, sizeof(*var));
return sizeof(*var);
}
/*
* 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 inline void
efivar_unregister(struct efivar_entry *var)
{
kobject_put(&var->kobj);
}
static int efivarfs_file_open(struct inode *inode, struct file *file)
{
file->private_data = inode->i_private;
return 0;
}
static int efi_status_to_err(efi_status_t status)
{
int err;
switch (status) {
case EFI_SUCCESS:
err = 0;
break;
case EFI_INVALID_PARAMETER:
err = -EINVAL;
break;
case EFI_OUT_OF_RESOURCES:
err = -ENOSPC;
break;
case EFI_DEVICE_ERROR:
err = -EIO;
break;
case EFI_WRITE_PROTECTED:
err = -EROFS;
break;
case EFI_SECURITY_VIOLATION:
err = -EACCES;
break;
case EFI_NOT_FOUND:
err = -ENOENT;
break;
default:
err = -EINVAL;
}
return err;
}
static ssize_t efivarfs_file_write(struct file *file,
const char __user *userbuf, size_t count, loff_t *ppos)
{
struct efivar_entry *var = file->private_data;
void *data;
u32 attributes;
struct inode *inode = file->f_mapping->host;
unsigned long datasize = count - sizeof(attributes);
ssize_t bytes = 0;
bool set = false;
if (count < sizeof(attributes))
return -EINVAL;
if (copy_from_user(&attributes, userbuf, sizeof(attributes)))
return -EFAULT;
if (attributes & ~(EFI_VARIABLE_MASK))
return -EINVAL;
data = kmalloc(datasize, GFP_KERNEL);
if (!data)
return -ENOMEM;
if (copy_from_user(data, userbuf + sizeof(attributes), datasize)) {
bytes = -EFAULT;
goto out;
}
bytes = efivar_entry_set_get_size(var, attributes, &datasize,
data, &set);
if (!set && bytes)
goto out;
if (!bytes) {
mutex_lock(&inode->i_mutex);
i_size_write(inode, datasize + sizeof(attributes));
mutex_unlock(&inode->i_mutex);
} else if (bytes == -ENOENT) {
drop_nlink(inode);
d_delete(file->f_dentry);
dput(file->f_dentry);
} else
pr_warn("efivarfs: inconsistent EFI variable implementation? "
"status=%zu\n", bytes);
bytes = count;
out:
kfree(data);
return bytes;
}
static ssize_t efivarfs_file_read(struct file *file, char __user *userbuf,
size_t count, loff_t *ppos)
{
struct efivar_entry *var = file->private_data;
unsigned long datasize = 0;
u32 attributes;
void *data;
ssize_t size = 0;
int err;
err = efivar_entry_size(var, &datasize);
if (err)
return err;
data = kmalloc(datasize + sizeof(attributes), GFP_KERNEL);
if (!data)
return -ENOMEM;
size = efivar_entry_get(var, &attributes, &datasize,
data + sizeof(attributes));
if (size)
goto out_free;
memcpy(data, &attributes, sizeof(attributes));
size = simple_read_from_buffer(userbuf, count, ppos,
data, datasize + sizeof(attributes));
out_free:
kfree(data);
return size;
}
static void efivarfs_evict_inode(struct inode *inode)
{
clear_inode(inode);
}
static const struct super_operations efivarfs_ops = {
.statfs = simple_statfs,
.drop_inode = generic_delete_inode,
.evict_inode = efivarfs_evict_inode,
.show_options = generic_show_options,
};
static struct super_block *efivarfs_sb;
static const struct inode_operations efivarfs_dir_inode_operations;
static const struct file_operations efivarfs_file_operations = {
.open = efivarfs_file_open,
.read = efivarfs_file_read,
.write = efivarfs_file_write,
.llseek = no_llseek,
};
static struct inode *efivarfs_get_inode(struct super_block *sb,
const struct inode *dir, int mode, dev_t dev)
{
struct inode *inode = new_inode(sb);
if (inode) {
inode->i_ino = get_next_ino();
inode->i_mode = mode;
inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
switch (mode & S_IFMT) {
case S_IFREG:
inode->i_fop = &efivarfs_file_operations;
break;
case S_IFDIR:
inode->i_op = &efivarfs_dir_inode_operations;
inode->i_fop = &simple_dir_operations;
inc_nlink(inode);
break;
}
}
return inode;
}
/*
* Return true if 'str' is a valid efivarfs filename of the form,
*
* VariableName-12345678-1234-1234-1234-1234567891bc
*/
static bool efivarfs_valid_name(const char *str, int len)
{
static const char dashes[EFI_VARIABLE_GUID_LEN] = {
[8] = 1, [13] = 1, [18] = 1, [23] = 1
};
const char *s = str + len - EFI_VARIABLE_GUID_LEN;
int i;
/*
* We need a GUID, plus at least one letter for the variable name,
* plus the '-' separator
*/
if (len < EFI_VARIABLE_GUID_LEN + 2)
return false;
/* GUID must be preceded by a '-' */
if (*(s - 1) != '-')
return false;
/*
* Validate that 's' is of the correct format, e.g.
*
* 12345678-1234-1234-1234-123456789abc
*/
for (i = 0; i < EFI_VARIABLE_GUID_LEN; i++) {
if (dashes[i]) {
if (*s++ != '-')
return false;
} else {
if (!isxdigit(*s++))
return false;
}
}
return true;
}
static void efivarfs_hex_to_guid(const char *str, efi_guid_t *guid)
{
guid->b[0] = hex_to_bin(str[6]) << 4 | hex_to_bin(str[7]);
guid->b[1] = hex_to_bin(str[4]) << 4 | hex_to_bin(str[5]);
guid->b[2] = hex_to_bin(str[2]) << 4 | hex_to_bin(str[3]);
guid->b[3] = hex_to_bin(str[0]) << 4 | hex_to_bin(str[1]);
guid->b[4] = hex_to_bin(str[11]) << 4 | hex_to_bin(str[12]);
guid->b[5] = hex_to_bin(str[9]) << 4 | hex_to_bin(str[10]);
guid->b[6] = hex_to_bin(str[16]) << 4 | hex_to_bin(str[17]);
guid->b[7] = hex_to_bin(str[14]) << 4 | hex_to_bin(str[15]);
guid->b[8] = hex_to_bin(str[19]) << 4 | hex_to_bin(str[20]);
guid->b[9] = hex_to_bin(str[21]) << 4 | hex_to_bin(str[22]);
guid->b[10] = hex_to_bin(str[24]) << 4 | hex_to_bin(str[25]);
guid->b[11] = hex_to_bin(str[26]) << 4 | hex_to_bin(str[27]);
guid->b[12] = hex_to_bin(str[28]) << 4 | hex_to_bin(str[29]);
guid->b[13] = hex_to_bin(str[30]) << 4 | hex_to_bin(str[31]);
guid->b[14] = hex_to_bin(str[32]) << 4 | hex_to_bin(str[33]);
guid->b[15] = hex_to_bin(str[34]) << 4 | hex_to_bin(str[35]);
}
static int efivarfs_create(struct inode *dir, struct dentry *dentry,
umode_t mode, bool excl)
{
struct inode *inode;
struct efivar_entry *var;
int namelen, i = 0, err = 0;
if (!efivarfs_valid_name(dentry->d_name.name, dentry->d_name.len))
return -EINVAL;
inode = efivarfs_get_inode(dir->i_sb, dir, mode, 0);
if (!inode)
return -ENOMEM;
var = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
if (!var) {
err = -ENOMEM;
goto out;
}
/* length of the variable name itself: remove GUID and separator */
namelen = dentry->d_name.len - EFI_VARIABLE_GUID_LEN - 1;
efivarfs_hex_to_guid(dentry->d_name.name + namelen + 1,
&var->var.VendorGuid);
for (i = 0; i < namelen; i++)
var->var.VariableName[i] = dentry->d_name.name[i];
var->var.VariableName[i] = '\0';
inode->i_private = var;
efivar_entry_add(var, &efivarfs_list);
d_instantiate(dentry, inode);
dget(dentry);
out:
if (err) {
kfree(var);
iput(inode);
}
return err;
}
static int efivarfs_unlink(struct inode *dir, struct dentry *dentry)
{
struct efivar_entry *var = dentry->d_inode->i_private;
if (efivar_entry_delete(var))
return -EINVAL;
drop_nlink(dentry->d_inode);
dput(dentry);
return 0;
};
/*
* Compare two efivarfs file names.
*
* An efivarfs filename is composed of two parts,
*
* 1. A case-sensitive variable name
* 2. A case-insensitive GUID
*
* So we need to perform a case-sensitive match on part 1 and a
* case-insensitive match on part 2.
*/
static int efivarfs_d_compare(const struct dentry *parent, const struct inode *pinode,
const struct dentry *dentry, const struct inode *inode,
unsigned int len, const char *str,
const struct qstr *name)
{
int guid = len - EFI_VARIABLE_GUID_LEN;
if (name->len != len)
return 1;
/* Case-sensitive compare for the variable name */
if (memcmp(str, name->name, guid))
return 1;
/* Case-insensitive compare for the GUID */
return strncasecmp(name->name + guid, str + guid, EFI_VARIABLE_GUID_LEN);
}
static int efivarfs_d_hash(const struct dentry *dentry,
const struct inode *inode, struct qstr *qstr)
{
unsigned long hash = init_name_hash();
const unsigned char *s = qstr->name;
unsigned int len = qstr->len;
if (!efivarfs_valid_name(s, len))
return -EINVAL;
while (len-- > EFI_VARIABLE_GUID_LEN)
hash = partial_name_hash(*s++, hash);
/* GUID is case-insensitive. */
while (len--)
hash = partial_name_hash(tolower(*s++), hash);
qstr->hash = end_name_hash(hash);
return 0;
}
/*
* Retaining negative dentries for an in-memory filesystem just wastes
* memory and lookup time: arrange for them to be deleted immediately.
*/
static int efivarfs_delete_dentry(const struct dentry *dentry)
{
return 1;
}
static struct dentry_operations efivarfs_d_ops = {
.d_compare = efivarfs_d_compare,
.d_hash = efivarfs_d_hash,
.d_delete = efivarfs_delete_dentry,
};
static struct dentry *efivarfs_alloc_dentry(struct dentry *parent, char *name)
{
struct dentry *d;
struct qstr q;
int err;
q.name = name;
q.len = strlen(name);
err = efivarfs_d_hash(NULL, NULL, &q);
if (err)
return ERR_PTR(err);
d = d_alloc(parent, &q);
if (d)
return d;
return ERR_PTR(-ENOMEM);
}
static int efivarfs_callback(efi_char16_t *name16, efi_guid_t vendor,
unsigned long name_size, void *data)
{
struct super_block *sb = (struct super_block *)data;
struct efivar_entry *entry;
struct inode *inode = NULL;
struct dentry *dentry, *root = sb->s_root;
unsigned long size = 0;
char *name;
int len, i;
int err = -ENOMEM;
entry = kmalloc(sizeof(*entry), GFP_KERNEL);
if (!entry)
return err;
memcpy(entry->var.VariableName, name16, name_size);
memcpy(&(entry->var.VendorGuid), &vendor, sizeof(efi_guid_t));
len = utf16_strlen(entry->var.VariableName);
/* name, plus '-', plus GUID, plus NUL*/
name = kmalloc(len + 1 + EFI_VARIABLE_GUID_LEN + 1, GFP_KERNEL);
if (!name)
goto fail;
for (i = 0; i < len; i++)
name[i] = entry->var.VariableName[i] & 0xFF;
name[len] = '-';
efi_guid_unparse(&entry->var.VendorGuid, name + len + 1);
name[len + EFI_VARIABLE_GUID_LEN+1] = '\0';
inode = efivarfs_get_inode(sb, root->d_inode, S_IFREG | 0644, 0);
if (!inode)
goto fail_name;
dentry = efivarfs_alloc_dentry(root, name);
if (IS_ERR(dentry)) {
err = PTR_ERR(dentry);
goto fail_inode;
}
/* copied by the above to local storage in the dentry. */
kfree(name);
efivar_entry_size(entry, &size);
efivar_entry_add(entry, &efivarfs_list);
mutex_lock(&inode->i_mutex);
inode->i_private = entry;
i_size_write(inode, size + sizeof(entry->var.Attributes));
mutex_unlock(&inode->i_mutex);
d_add(dentry, inode);
return 0;
fail_inode:
iput(inode);
fail_name:
kfree(name);
fail:
kfree(entry);
return err;
}
static int efivarfs_destroy(struct efivar_entry *entry, void *data)
{
efivar_entry_remove(entry);
kfree(entry);
return 0;
}
static int efivarfs_fill_super(struct super_block *sb, void *data, int silent)
{
struct inode *inode = NULL;
struct dentry *root;
int err;
efivarfs_sb = sb;
sb->s_maxbytes = MAX_LFS_FILESIZE;
sb->s_blocksize = PAGE_CACHE_SIZE;
sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
sb->s_magic = EFIVARFS_MAGIC;
sb->s_op = &efivarfs_ops;
sb->s_d_op = &efivarfs_d_ops;
sb->s_time_gran = 1;
inode = efivarfs_get_inode(sb, NULL, S_IFDIR | 0755, 0);
if (!inode)
return -ENOMEM;
inode->i_op = &efivarfs_dir_inode_operations;
root = d_make_root(inode);
sb->s_root = root;
if (!root)
return -ENOMEM;
INIT_LIST_HEAD(&efivarfs_list);
err = efivar_init(efivarfs_callback, (void *)sb, false,
true, &efivarfs_list);
if (err)
__efivar_entry_iter(efivarfs_destroy, &efivarfs_list, NULL, NULL);
return err;
}
static struct dentry *efivarfs_mount(struct file_system_type *fs_type,
int flags, const char *dev_name, void *data)
{
return mount_single(fs_type, flags, data, efivarfs_fill_super);
}
static void efivarfs_kill_sb(struct super_block *sb)
{
kill_litter_super(sb);
efivarfs_sb = NULL;
/* Remove all entries and destroy */
__efivar_entry_iter(efivarfs_destroy, &efivarfs_list, NULL, NULL);
}
static struct file_system_type efivarfs_type = {
.name = "efivarfs",
.mount = efivarfs_mount,
.kill_sb = efivarfs_kill_sb,
};
MODULE_ALIAS_FS("efivarfs");
/*
* Handle negative dentry.
*/
static struct dentry *efivarfs_lookup(struct inode *dir, struct dentry *dentry,
unsigned int flags)
{
if (dentry->d_name.len > NAME_MAX)
return ERR_PTR(-ENAMETOOLONG);
d_add(dentry, NULL);
return NULL;
}
static const struct inode_operations efivarfs_dir_inode_operations = {
.lookup = efivarfs_lookup,
.unlink = efivarfs_unlink,
.create = efivarfs_create,
};
#ifdef CONFIG_EFI_VARS_PSTORE
static int efi_pstore_open(struct pstore_info *psi)
{
efivar_entry_iter_begin();
psi->data = NULL;
return 0;
}
static int efi_pstore_close(struct pstore_info *psi)
{
efivar_entry_iter_end();
psi->data = NULL;
return 0;
}
struct pstore_read_data {
u64 *id;
enum pstore_type_id *type;
int *count;
struct timespec *timespec;
char **buf;
};
static int efi_pstore_read_func(struct efivar_entry *entry, void *data)
{
efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
struct pstore_read_data *cb_data = data;
char name[DUMP_NAME_LEN];
int i;
int cnt;
unsigned int part;
unsigned long time, size;
if (efi_guidcmp(entry->var.VendorGuid, vendor))
return 0;
for (i = 0; i < DUMP_NAME_LEN; i++)
name[i] = entry->var.VariableName[i];
if (sscanf(name, "dump-type%u-%u-%d-%lu",
cb_data->type, &part, &cnt, &time) == 4) {
*cb_data->id = part;
*cb_data->count = cnt;
cb_data->timespec->tv_sec = time;
cb_data->timespec->tv_nsec = 0;
} else if (sscanf(name, "dump-type%u-%u-%lu",
cb_data->type, &part, &time) == 3) {
/*
* Check if an old format,
* which doesn't support holding
* multiple logs, remains.
*/
*cb_data->id = part;
*cb_data->count = 0;
cb_data->timespec->tv_sec = time;
cb_data->timespec->tv_nsec = 0;
} else
return 0;
__efivar_entry_size(entry, &size);
*cb_data->buf = kmalloc(size, GFP_KERNEL);
if (*cb_data->buf == NULL)
return -ENOMEM;
memcpy(*cb_data->buf, entry->var.Data, size);
return size;
}
static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
int *count, struct timespec *timespec,
char **buf, struct pstore_info *psi)
{
struct pstore_read_data data;
data.id = id;
data.type = type;
data.count = count;
data.timespec = timespec;
data.buf = buf;
return __efivar_entry_iter(efi_pstore_read_func, &efivar_sysfs_list, &data,
(struct efivar_entry **)&psi->data);
}
static int efi_pstore_write(enum pstore_type_id type,
enum kmsg_dump_reason reason, u64 *id,
unsigned int part, int count, size_t size,
struct pstore_info *psi)
{
char name[DUMP_NAME_LEN];
efi_char16_t efi_name[DUMP_NAME_LEN];
efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
int i, ret = 0;
sprintf(name, "dump-type%u-%u-%d-%lu", type, part, count,
get_seconds());
for (i = 0; i < DUMP_NAME_LEN; i++)
efi_name[i] = name[i];
ret = efivar_entry_set_safe(efi_name, vendor, PSTORE_EFI_ATTRIBUTES,
!pstore_cannot_block_path(reason),
size, psi->buf);
if (reason == KMSG_DUMP_OOPS && efivar_wq_enabled)
schedule_work(&efivar_work);
*id = part;
return ret;
};
struct pstore_erase_data {
u64 id;
enum pstore_type_id type;
int count;
struct timespec time;
efi_char16_t *name;
};
/*
* Clean up an entry with the same name
*/
static int efi_pstore_erase_func(struct efivar_entry *entry, void *data)
{
struct pstore_erase_data *ed = data;
efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
efi_char16_t efi_name_old[DUMP_NAME_LEN];
efi_char16_t *efi_name = ed->name;
unsigned long utf16_len = utf16_strlen(ed->name);
char name_old[DUMP_NAME_LEN];
int i;
if (efi_guidcmp(entry->var.VendorGuid, vendor))
return 0;
if (utf16_strncmp(entry->var.VariableName,
efi_name, (size_t)utf16_len)) {
/*
* Check if an old format, which doesn't support
* holding multiple logs, remains.
*/
sprintf(name_old, "dump-type%u-%u-%lu", ed->type,
(unsigned int)ed->id, ed->time.tv_sec);
for (i = 0; i < DUMP_NAME_LEN; i++)
efi_name_old[i] = name_old[i];
if (utf16_strncmp(entry->var.VariableName, efi_name_old,
utf16_strlen(efi_name_old)))
return 0;
}
/* found */
__efivar_entry_delete(entry);
return 1;
}
static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count,
struct timespec time, struct pstore_info *psi)
{
struct pstore_erase_data edata;
struct efivar_entry *entry;
char name[DUMP_NAME_LEN];
efi_char16_t efi_name[DUMP_NAME_LEN];
int found, i;
sprintf(name, "dump-type%u-%u-%d-%lu", type, (unsigned int)id, count,
time.tv_sec);
for (i = 0; i < DUMP_NAME_LEN; i++)
efi_name[i] = name[i];
edata.id = id;
edata.type = type;
edata.count = count;
edata.time = time;
edata.name = efi_name;
efivar_entry_iter_begin();
found = __efivar_entry_iter(efi_pstore_erase_func, &efivar_sysfs_list, &edata, &entry);
efivar_entry_iter_end();
if (found)
efivar_unregister(entry);
return 0;
}
static struct pstore_info efi_pstore_info = {
.owner = THIS_MODULE,
.name = "efi",
.open = efi_pstore_open,
.close = efi_pstore_close,
.read = efi_pstore_read,
.write = efi_pstore_write,
.erase = efi_pstore_erase,
};
static void efivar_pstore_register(void)
{
efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL);
if (efi_pstore_info.buf) {
efi_pstore_info.bufsize = 1024;
spin_lock_init(&efi_pstore_info.buf_lock);
pstore_register(&efi_pstore_info);
}
}
#else
static void efivar_pstore_register(void)
{
return;
}
#endif
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 efi_variable *new_var = (struct efi_variable *)buf;
struct efivar_entry *new_entry;
int err;
if (!capable(CAP_SYS_ADMIN))
return -EACCES;
if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
efivar_validate(new_var, new_var->Data, new_var->DataSize) == false) {
printk(KERN_ERR "efivars: Malformed variable content\n");
return -EINVAL;
}
new_entry = kzalloc(sizeof(*new_entry), GFP_KERNEL);
if (!new_entry)
return -ENOMEM;
memcpy(&new_entry->var, new_var, sizeof(*new_var));
err = efivar_entry_set(new_entry, new_var->Attributes, new_var->DataSize,
new_var->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 efivar_entry *entry;
int err = 0;
if (!capable(CAP_SYS_ADMIN))
return -EACCES;
efivar_entry_iter_begin();
entry = efivar_entry_find(del_var->VariableName, del_var->VendorGuid,
&efivar_sysfs_list, true);
if (!entry)
err = -EINVAL;
else if (__efivar_entry_delete(entry))
err = -EIO;
efivar_entry_iter_end();
if (err)
return err;
efivar_unregister(entry);
/* It's dead Jim.... */
return count;
}
static bool variable_is_present(efi_char16_t *variable_name, efi_guid_t *vendor,
struct list_head *head)
{
struct efivar_entry *entry, *n;
unsigned long strsize1, strsize2;
bool found = false;
strsize1 = utf16_strsize(variable_name, 1024);
list_for_each_entry_safe(entry, n, head, list) {
strsize2 = utf16_strsize(entry->var.VariableName, 1024);
if (strsize1 == strsize2 &&
!memcmp(variable_name, &(entry->var.VariableName),
strsize2) &&
!efi_guidcmp(entry->var.VendorGuid,
*vendor)) {
found = true;
break;
}
}
return found;
}
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;
}
/*
* Returns the size of variable_name, in bytes, including the
* terminating NULL character, or variable_name_size if no NULL
* character is found among the first variable_name_size bytes.
*/
static unsigned long var_name_strnsize(efi_char16_t *variable_name,
unsigned long variable_name_size)
{
unsigned long len;
efi_char16_t c;
/*
* The variable name is, by definition, a NULL-terminated
* string, so make absolutely sure that variable_name_size is
* the value we expect it to be. If not, return the real size.
*/
for (len = 2; len <= variable_name_size; len += sizeof(c)) {
c = variable_name[(len / sizeof(c)) - 1];
if (!c)
break;
}
return min(len, variable_name_size);
}
static void efivar_update_sysfs_entries(struct work_struct *work)
{
struct efivar_entry *entry;
int err;
entry = kzalloc(sizeof(*entry), GFP_KERNEL);
if (!entry)
return;
/* Add new sysfs entries */
while (1) {
memset(entry, 0, sizeof(*entry));
err = efivar_init(efivar_update_sysfs_entry, entry,
true, false, &efivar_sysfs_list);
if (!err)
break;
efivar_create_sysfs_entry(entry);
}
kfree(entry);
}
/*
* Let's not leave out systab information that snuck into
* the efivars driver
*/
static ssize_t systab_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
char *str = buf;
if (!kobj || !buf)
return -EINVAL;
if (efi.mps != EFI_INVALID_TABLE_ADDR)
str += sprintf(str, "MPS=0x%lx\n", efi.mps);
if (efi.acpi20 != EFI_INVALID_TABLE_ADDR)
str += sprintf(str, "ACPI20=0x%lx\n", efi.acpi20);
if (efi.acpi != EFI_INVALID_TABLE_ADDR)
str += sprintf(str, "ACPI=0x%lx\n", efi.acpi);
if (efi.smbios != EFI_INVALID_TABLE_ADDR)
str += sprintf(str, "SMBIOS=0x%lx\n", efi.smbios);
if (efi.hcdp != EFI_INVALID_TABLE_ADDR)
str += sprintf(str, "HCDP=0x%lx\n", efi.hcdp);
if (efi.boot_info != EFI_INVALID_TABLE_ADDR)
str += sprintf(str, "BOOTINFO=0x%lx\n", efi.boot_info);
if (efi.uga != EFI_INVALID_TABLE_ADDR)
str += sprintf(str, "UGA=0x%lx\n", efi.uga);
return str - buf;
}
static struct kobj_attribute efi_attr_systab =
__ATTR(systab, 0400, systab_show, NULL);
static struct attribute *efi_subsys_attrs[] = {
&efi_attr_systab.attr,
NULL, /* maybe more in the future? */
};
static struct attribute_group efi_subsys_attr_group = {
.attrs = efi_subsys_attrs,
};
static struct kobject *efi_kobj;
/**
* 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 = utf16_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) {
kfree(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_unparse(&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 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;
}
/*
* Print a warning when duplicate EFI variables are encountered and
* disable the sysfs workqueue since the firmware is buggy.
*/
static void dup_variable_bug(efi_char16_t *s16, efi_guid_t *vendor_guid,
unsigned long len16)
{
size_t i, len8 = len16 / sizeof(efi_char16_t);
char *s8;
/*
* Disable the workqueue since the algorithm it uses for
* detecting new variables won't work with this buggy
* implementation of GetNextVariableName().
*/
efivar_wq_enabled = false;
s8 = kzalloc(len8, GFP_KERNEL);
if (!s8)
return;
for (i = 0; i < len8; i++)
s8[i] = s16[i];
printk(KERN_WARNING "efivars: duplicate variable: %s-%pUl\n",
s8, vendor_guid);
kfree(s8);
}
static struct kobject *efivars_kobj;
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);
kobject_put(efivars_kobj);
kset_unregister(efivars_kset);
}
int efivars_sysfs_init(void)
{
struct kobject *parent_kobj = efivars_kobject();
int error = 0;
/* 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;
}
efivars_kobj = kobject_create_and_add("efivars", parent_kobj);
if (!efivars_kobj) {
pr_err("efivars: Subsystem registration failed.\n");
kset_unregister(efivars_kset);
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;
}
EXPORT_SYMBOL_GPL(efivars_sysfs_init);
/**
* efivar_init - build the initial list of EFI variables
* @func: callback function to invoke for every variable
* @data: function-specific data to pass to @func
* @atomic: do we need to execute the @func-loop atomically?
* @duplicates: error if we encounter duplicates on @head?
* @head: initialised head of variable list
*
* Get every EFI variable from the firmware and invoke @func. @func
* should call efivar_entry_add() to build the list of variables.
*
* Returns 0 on success, or a kernel error code on failure.
*/
int efivar_init(int (*func)(efi_char16_t *, efi_guid_t, unsigned long, void *),
void *data, bool atomic, bool duplicates,
struct list_head *head)
{
const struct efivar_operations *ops = __efivars->ops;
unsigned long variable_name_size = 1024;
efi_char16_t *variable_name;
efi_status_t status;
efi_guid_t vendor_guid;
int err = 0;
variable_name = kzalloc(variable_name_size, GFP_KERNEL);
if (!variable_name) {
printk(KERN_ERR "efivars: Memory allocation failed.\n");
return -ENOMEM;
}
spin_lock_irq(&__efivars->lock);
/*
* Per EFI spec, the maximum storage allocated for both
* the variable name and variable data is 1024 bytes.
*/
do {
variable_name_size = 1024;
status = ops->get_next_variable(&variable_name_size,
variable_name,
&vendor_guid);
switch (status) {
case EFI_SUCCESS:
if (!atomic)
spin_unlock_irq(&__efivars->lock);
variable_name_size = var_name_strnsize(variable_name,
variable_name_size);
/*
* Some firmware implementations return the
* same variable name on multiple calls to
* get_next_variable(). Terminate the loop
* immediately as there is no guarantee that
* we'll ever see a different variable name,
* and may end up looping here forever.
*/
if (duplicates &&
variable_is_present(variable_name, &vendor_guid, head)) {
dup_variable_bug(variable_name, &vendor_guid,
variable_name_size);
if (!atomic)
spin_lock_irq(&__efivars->lock);
status = EFI_NOT_FOUND;
break;
}
err = func(variable_name, vendor_guid, variable_name_size, data);
if (err)
status = EFI_NOT_FOUND;
if (!atomic)
spin_lock_irq(&__efivars->lock);
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);
spin_unlock_irq(&__efivars->lock);
kfree(variable_name);
return err;
}
EXPORT_SYMBOL_GPL(efivar_init);
/**
* efivar_entry_add - add entry to variable list
* @entry: entry to add to list
* @head: list head
*/
void efivar_entry_add(struct efivar_entry *entry, struct list_head *head)
{
spin_lock_irq(&__efivars->lock);
list_add(&entry->list, head);
spin_unlock_irq(&__efivars->lock);
}
EXPORT_SYMBOL_GPL(efivar_entry_add);
/**
* efivar_entry_remove - remove entry from variable list
* @entry: entry to remove from list
*/
void efivar_entry_remove(struct efivar_entry *entry)
{
spin_lock_irq(&__efivars->lock);
list_del(&entry->list);
spin_unlock_irq(&__efivars->lock);
}
EXPORT_SYMBOL_GPL(efivar_entry_remove);
/*
* efivar_entry_list_del_unlock - remove entry from variable list
* @entry: entry to remove
*
* Remove @entry from the variable list and release the list lock.
*
* NOTE: slightly weird locking semantics here - we expect to be
* called with the efivars lock already held, and we release it before
* returning. This is because this function is usually called after
* set_variable() while the lock is still held.
*/
static void efivar_entry_list_del_unlock(struct efivar_entry *entry)
{
WARN_ON(!spin_is_locked(&__efivars->lock));
list_del(&entry->list);
spin_unlock_irq(&__efivars->lock);
}
/**
* __efivar_entry_delete - delete an EFI variable
* @entry: entry containing EFI variable to delete
*
* Delete the variable from the firmware and remove @entry from the
* variable list. It is the caller's responsibility to free @entry
* once we return.
*
* This function differs from efivar_entry_delete() because it is
* safe to be called from within a efivar_entry_iter_begin() and
* efivar_entry_iter_end() region, unlike efivar_entry_delete().
*
* Returns 0 on success, or a converted EFI status code if
* set_variable() fails. If set_variable() fails the entry remains
* on the list.
*/
int __efivar_entry_delete(struct efivar_entry *entry)
{
const struct efivar_operations *ops = __efivars->ops;
efi_status_t status;
WARN_ON(!spin_is_locked(&__efivars->lock));
status = ops->set_variable(entry->var.VariableName,
&entry->var.VendorGuid,
0, 0, NULL);
if (status)
return efi_status_to_err(status);
list_del(&entry->list);
return 0;
}
EXPORT_SYMBOL_GPL(__efivar_entry_delete);
/**
* efivar_entry_delete - delete variable and remove entry from list
* @entry: entry containing variable to delete
*
* Delete the variable from the firmware and remove @entry from the
* variable list. It is the caller's responsibility to free @entry
* once we return.
*
* Returns 0 on success, or a converted EFI status code if
* set_variable() fails.
*/
int efivar_entry_delete(struct efivar_entry *entry)
{
const struct efivar_operations *ops = __efivars->ops;
efi_status_t status;
spin_lock_irq(&__efivars->lock);
status = ops->set_variable(entry->var.VariableName,
&entry->var.VendorGuid,
0, 0, NULL);
if (!(status == EFI_SUCCESS || status == EFI_NOT_FOUND)) {
spin_unlock_irq(&__efivars->lock);
return efi_status_to_err(status);
}
efivar_entry_list_del_unlock(entry);
return 0;
}
EXPORT_SYMBOL_GPL(efivar_entry_delete);
/**
* efivar_entry_set - call set_variable()
* @entry: entry containing the EFI variable to write
* @attributes: variable attributes
* @size: size of @data buffer
* @data: buffer containing variable data
* @head: head of variable list
*
* Calls set_variable() for an EFI variable. If creating a new EFI
* variable, this function is usually followed by efivar_entry_add().
*
* Before writing the variable, the remaining EFI variable storage
* space is checked to ensure there is enough room available.
*
* If @head is not NULL a lookup is performed to determine whether
* the entry is already on the list.
*
* Returns 0 on success, -EEXIST if a lookup is performed and the entry
* already exists on the list, or a converted EFI status code if
* set_variable() fails.
*/
int efivar_entry_set(struct efivar_entry *entry, u32 attributes,
unsigned long size, void *data, struct list_head *head)
{
const struct efivar_operations *ops = __efivars->ops;
efi_status_t status;
efi_char16_t *name = entry->var.VariableName;
efi_guid_t vendor = entry->var.VendorGuid;
spin_lock_irq(&__efivars->lock);
if (head && efivar_entry_find(name, vendor, head, false)) {
spin_unlock_irq(&__efivars->lock);
return -EEXIST;
}
status = check_var_size(attributes, size + utf16_strsize(name, 1024));
if (status == EFI_SUCCESS || status == EFI_UNSUPPORTED)
status = ops->set_variable(name, &vendor,
attributes, size, data);
spin_unlock_irq(&__efivars->lock);
return efi_status_to_err(status);
}
EXPORT_SYMBOL_GPL(efivar_entry_set);
/**
* efivar_entry_set_safe - call set_variable() if enough space in firmware
* @name: buffer containing the variable name
* @vendor: variable vendor guid
* @attributes: variable attributes
* @block: can we block in this context?
* @size: size of @data buffer
* @data: buffer containing variable data
*
* Ensures there is enough free storage in the firmware for this variable, and
* if so, calls set_variable(). If creating a new EFI variable, this function
* is usually followed by efivar_entry_add().
*
* Returns 0 on success, -ENOSPC if the firmware does not have enough
* space for set_variable() to succeed, or a converted EFI status code
* if set_variable() fails.
*/
int efivar_entry_set_safe(efi_char16_t *name, efi_guid_t vendor, u32 attributes,
bool block, unsigned long size, void *data)
{
const struct efivar_operations *ops = __efivars->ops;
unsigned long flags;
efi_status_t status;
if (!ops->query_variable_info)
return -ENOSYS;
if (!block && !spin_trylock_irqsave(&__efivars->lock, flags))
return -EBUSY;
else
spin_lock_irqsave(&__efivars->lock, flags);
status = check_var_size(attributes, size + utf16_strsize(name, 1024));
if (status != EFI_SUCCESS) {
spin_unlock_irqrestore(&__efivars->lock, flags);
return -ENOSPC;
}
status = ops->set_variable(name, &vendor, attributes, size, data);
spin_unlock_irqrestore(&__efivars->lock, flags);
return efi_status_to_err(status);
}
EXPORT_SYMBOL_GPL(efivar_entry_set_safe);
/**
* efivar_entry_find - search for an entry
* @name: the EFI variable name
* @guid: the EFI variable vendor's guid
* @head: head of the variable list
* @remove: should we remove the entry from the list?
*
* Search for an entry on the variable list that has the EFI variable
* name @name and vendor guid @guid. If an entry is found on the list
* and @remove is true, the entry is removed from the list.
*
* The caller MUST call efivar_entry_iter_begin() and
* efivar_entry_iter_end() before and after the invocation of this
* function, respectively.
*
* Returns the entry if found on the list, %NULL otherwise.
*/
struct efivar_entry *efivar_entry_find(efi_char16_t *name, efi_guid_t guid,
struct list_head *head, bool remove)
{
struct efivar_entry *entry, *n;
int strsize1, strsize2;
bool found = false;
WARN_ON(!spin_is_locked(&__efivars->lock));
list_for_each_entry_safe(entry, n, head, list) {
strsize1 = utf16_strsize(name, 1024);
strsize2 = utf16_strsize(entry->var.VariableName, 1024);
if (strsize1 == strsize2 &&
!memcmp(name, &(entry->var.VariableName), strsize1) &&
!efi_guidcmp(guid, entry->var.VendorGuid)) {
found = true;
break;
}
}
if (!found)
return NULL;
if (remove)
list_del(&entry->list);
return entry;
}
EXPORT_SYMBOL_GPL(efivar_entry_find);
/**
* __efivar_entry_size - obtain the size of a variable
* @entry: entry for this variable
* @size: location to store the variable's size
*
* The caller MUST call efivar_entry_iter_begin() and
* efivar_entry_iter_end() before and after the invocation of this
* function, respectively.
*/
int __efivar_entry_size(struct efivar_entry *entry, unsigned long *size)
{
const struct efivar_operations *ops = __efivars->ops;
efi_status_t status;
WARN_ON(!spin_is_locked(&__efivars->lock));
*size = 0;
status = ops->get_variable(entry->var.VariableName,
&entry->var.VendorGuid, NULL, size, NULL);
if (status != EFI_BUFFER_TOO_SMALL)
return efi_status_to_err(status);
return 0;
}
EXPORT_SYMBOL_GPL(__efivar_entry_size);
/**
* efivar_entry_size - obtain the size of a variable
* @entry: entry for this variable
* @size: location to store the variable's size
*/
int efivar_entry_size(struct efivar_entry *entry, unsigned long *size)
{
const struct efivar_operations *ops = __efivars->ops;
efi_status_t status;
*size = 0;
spin_lock_irq(&__efivars->lock);
status = ops->get_variable(entry->var.VariableName,
&entry->var.VendorGuid, NULL, size, NULL);
spin_unlock_irq(&__efivars->lock);
if (status != EFI_BUFFER_TOO_SMALL)
return efi_status_to_err(status);
return 0;
}
EXPORT_SYMBOL_GPL(efivar_entry_size);
/**
* efivar_entry_get - call get_variable()
* @entry: read data for this variable
* @attributes: variable attributes
* @size: size of @data buffer
* @data: buffer to store variable data
*/
int efivar_entry_get(struct efivar_entry *entry, u32 *attributes,
unsigned long *size, void *data)
{
const struct efivar_operations *ops = __efivars->ops;
efi_status_t status;
spin_lock_irq(&__efivars->lock);
status = ops->get_variable(entry->var.VariableName,
&entry->var.VendorGuid,
attributes, size, data);
spin_unlock_irq(&__efivars->lock);
return efi_status_to_err(status);
}
EXPORT_SYMBOL_GPL(efivar_entry_get);
/**
* efivar_entry_set_get_size - call set_variable() and get new size (atomic)
* @entry: entry containing variable to set and get
* @attributes: attributes of variable to be written
* @size: size of data buffer
* @data: buffer containing data to write
* @set: did the set_variable() call succeed?
*
* This is a pretty special (complex) function. See efivarfs_file_write().
*
* Atomically call set_variable() for @entry and if the call is
* successful, return the new size of the variable from get_variable()
* in @size. The success of set_variable() is indicated by @set.
*
* Returns 0 on success, -EINVAL if the variable data is invalid,
* -ENOSPC if the firmware does not have enough available space, or a
* converted EFI status code if either of set_variable() or
* get_variable() fail.
*
* If the EFI variable does not exist when calling set_variable()
* (EFI_NOT_FOUND), @entry is removed from the variable list.
*/
int efivar_entry_set_get_size(struct efivar_entry *entry, u32 attributes,
unsigned long *size, void *data, bool *set)
{
const struct efivar_operations *ops = __efivars->ops;
efi_char16_t *name = entry->var.VariableName;
efi_guid_t *vendor = &entry->var.VendorGuid;
efi_status_t status;
int err;
*set = false;
if (efivar_validate(&entry->var, data, *size) == false)
return -EINVAL;
/*
* The lock here protects the get_variable call, the conditional
* set_variable call, and removal of the variable from the efivars
* list (in the case of an authenticated delete).
*/
spin_lock_irq(&__efivars->lock);
/*
* Ensure that the available space hasn't shrunk below the safe level
*/
status = check_var_size(attributes, *size + utf16_strsize(name, 1024));
if (status != EFI_SUCCESS) {
if (status != EFI_UNSUPPORTED) {
err = efi_status_to_err(status);
goto out;
}
if (*size > 65536) {
err = -ENOSPC;
goto out;
}
}
status = ops->set_variable(name, vendor, attributes, *size, data);
if (status != EFI_SUCCESS) {
err = efi_status_to_err(status);
goto out;
}
*set = true;
/*
* Writing to the variable may have caused a change in size (which
* could either be an append or an overwrite), or the variable to be
* deleted. Perform a GetVariable() so we can tell what actually
* happened.
*/
*size = 0;
status = ops->get_variable(entry->var.VariableName,
&entry->var.VendorGuid,
NULL, size, NULL);
if (status == EFI_NOT_FOUND)
efivar_entry_list_del_unlock(entry);
else
spin_unlock_irq(&__efivars->lock);
if (status && status != EFI_BUFFER_TOO_SMALL)
return efi_status_to_err(status);
return 0;
out:
spin_unlock_irq(&__efivars->lock);
return err;
}
EXPORT_SYMBOL_GPL(efivar_entry_set_get_size);
/**
* efivar_entry_iter_begin - begin iterating the variable list
*
* Lock the variable list to prevent entry insertion and removal until
* efivar_entry_iter_end() is called. This function is usually used in
* conjunction with __efivar_entry_iter() or efivar_entry_iter().
*/
void efivar_entry_iter_begin(void)
{
spin_lock_irq(&__efivars->lock);
}
EXPORT_SYMBOL_GPL(efivar_entry_iter_begin);
/**
* efivar_entry_iter_end - finish iterating the variable list
*
* Unlock the variable list and allow modifications to the list again.
*/
void efivar_entry_iter_end(void)
{
spin_unlock_irq(&__efivars->lock);
}
EXPORT_SYMBOL_GPL(efivar_entry_iter_end);
/**
* __efivar_entry_iter - iterate over variable list
* @func: callback function
* @head: head of the variable list
* @data: function-specific data to pass to callback
* @prev: entry to begin iterating from
*
* Iterate over the list of EFI variables and call @func with every
* entry on the list. It is safe for @func to remove entries in the
* list via efivar_entry_delete().
*
* You MUST call efivar_enter_iter_begin() before this function, and
* efivar_entry_iter_end() afterwards.
*
* It is possible to begin iteration from an arbitrary entry within
* the list by passing @prev. @prev is updated on return to point to
* the last entry passed to @func. To begin iterating from the
* beginning of the list @prev must be %NULL.
*
* The restrictions for @func are the same as documented for
* efivar_entry_iter().
*/
int __efivar_entry_iter(int (*func)(struct efivar_entry *, void *),
struct list_head *head, void *data,
struct efivar_entry **prev)
{
struct efivar_entry *entry, *n;
int err = 0;
if (!prev || !*prev) {
list_for_each_entry_safe(entry, n, head, list) {
err = func(entry, data);
if (err)
break;
}
if (prev)
*prev = entry;
return err;
}
list_for_each_entry_safe_continue((*prev), n, head, list) {
err = func(*prev, data);
if (err)
break;
}
return err;
}
EXPORT_SYMBOL_GPL(__efivar_entry_iter);
/**
* efivar_entry_iter - iterate over variable list
* @func: callback function
* @head: head of variable list
* @data: function-specific data to pass to callback
*
* Iterate over the list of EFI variables and call @func with every
* entry on the list. It is safe for @func to remove entries in the
* list via efivar_entry_delete() while iterating.
*
* Some notes for the callback function:
* - a non-zero return value indicates an error and terminates the loop
* - @func is called from atomic context
*/
int efivar_entry_iter(int (*func)(struct efivar_entry *, void *),
struct list_head *head, void *data)
{
int err = 0;
efivar_entry_iter_begin();
err = __efivar_entry_iter(func, head, data, NULL);
efivar_entry_iter_end();
return err;
}
EXPORT_SYMBOL_GPL(efivar_entry_iter);
/**
* efivars_kobject - get the kobject for the registered efivars
*
* If efivars_register() has not been called we return NULL,
* otherwise return the kobject used at registration time.
*/
struct kobject *efivars_kobject(void)
{
if (!__efivars)
return NULL;
return __efivars->kobject;
}
EXPORT_SYMBOL_GPL(efivars_kobject);
/**
* efivars_register - register an efivars
* @efivars: efivars to register
* @ops: efivars operations
* @kobject: @efivars-specific kobject
*
* Only a single efivars can be registered at any time.
*/
int efivars_register(struct efivars *efivars,
const struct efivar_operations *ops,
struct kobject *kobject)
{
spin_lock_init(&efivars->lock);
efivars->ops = ops;
efivars->kobject = kobject;
__efivars = efivars;
if (!efivars_pstore_disable)
efivar_pstore_register();
register_filesystem(&efivarfs_type);
return 0;
}
EXPORT_SYMBOL_GPL(efivars_register);
/**
* efivars_unregister - unregister an efivars
* @efivars: efivars to unregister
*
* The caller must have already removed every entry from the list,
* failure to do so is an error.
*/
int efivars_unregister(struct efivars *efivars)
{
int rv;
if (!__efivars) {
printk(KERN_ERR "efivars not registered\n");
rv = -EINVAL;
goto out;
}
if (__efivars != efivars) {
rv = -EINVAL;
goto out;
}
__efivars = NULL;
rv = 0;
out:
return rv;
}
EXPORT_SYMBOL_GPL(efivars_unregister);
static struct efivars generic_efivars;
static struct efivar_operations generic_ops;
static int generic_ops_register(void)
{
int error;
generic_ops.get_variable = efi.get_variable;
generic_ops.set_variable = efi.set_variable;
generic_ops.get_next_variable = efi.get_next_variable;
generic_ops.query_variable_info = efi.query_variable_info;
error = efivars_register(&generic_efivars, &generic_ops, efi_kobj);
if (error)
return error;
error = efivars_sysfs_init();
if (error)
efivars_unregister(&generic_efivars);
return error;
}
static void generic_ops_unregister(void)
{
efivars_sysfs_exit();
efivars_unregister(&generic_efivars);
}
/*
* 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)
{
int error;
if (!efi_enabled(EFI_RUNTIME_SERVICES))
return 0;
/* Register the efi directory at /sys/firmware/efi */
efi_kobj = kobject_create_and_add("efi", firmware_kobj);
if (!efi_kobj) {
printk(KERN_ERR "efivars: Firmware registration failed.\n");
return -ENOMEM;
}
error = generic_ops_register();
if (error)
goto err_put;
/* Don't forget the systab entry */
error = sysfs_create_group(efi_kobj, &efi_subsys_attr_group);
if (error) {
printk(KERN_ERR
"efivars: Sysfs attribute export failed with error %d.\n",
error);
goto err_unregister;
}
return 0;
err_unregister:
generic_ops_unregister();
err_put:
kobject_put(efi_kobj);
return error;
}
static void __exit
efivars_exit(void)
{
cancel_work_sync(&efivar_work);
if (efi_enabled(EFI_RUNTIME_SERVICES)) {
generic_ops_unregister();
kobject_put(efi_kobj);
}
}
module_init(efivars_init);
module_exit(efivars_exit);
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