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WSL2-Linux-Kernel/drivers/firmware/efivars.c

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52 KiB
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/ucs2_string.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
/*
* Length of a GUID string (strlen("aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee"))
* not including trailing NUL
*/
#define GUID_LEN 36
static bool efivars_pstore_disable =
IS_ENABLED(CONFIG_EFI_VARS_PSTORE_DEFAULT_DISABLE);
module_param_named(pstore_disable, efivars_pstore_disable, bool, 0644);
/*
* 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 efivars *efivars;
struct efi_variable var;
struct list_head list;
struct kobject kobj;
};
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);
};
static struct efivars __efivars;
static struct efivar_operations ops;
#define PSTORE_EFI_ATTRIBUTES \
(EFI_VARIABLE_NON_VOLATILE | \
EFI_VARIABLE_BOOTSERVICE_ACCESS | \
EFI_VARIABLE_RUNTIME_ACCESS)
#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 efivars *efivars,
unsigned long variable_name_size,
efi_char16_t *variable_name,
efi_guid_t *vendor_guid);
/*
* 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;
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 = ucs2_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 = ucs2_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 },
};
static bool
validate_var(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;
}
static efi_status_t
get_var_data_locked(struct efivars *efivars, struct efi_variable *var)
{
efi_status_t status;
var->DataSize = 1024;
status = efivars->ops->get_variable(var->VariableName,
&var->VendorGuid,
&var->Attributes,
&var->DataSize,
var->Data);
return status;
}
static efi_status_t
get_var_data(struct efivars *efivars, struct efi_variable *var)
{
efi_status_t status;
unsigned long flags;
spin_lock_irqsave(&efivars->lock, flags);
status = get_var_data_locked(efivars, var);
spin_unlock_irqrestore(&efivars->lock, flags);
if (status != EFI_SUCCESS) {
printk(KERN_WARNING "efivars: get_variable() failed 0x%lx!\n",
status);
}
return status;
}
static efi_status_t
check_var_size_locked(struct efivars *efivars, u32 attributes,
unsigned long size)
{
const struct efivar_operations *fops = efivars->ops;
if (!efivars->ops->query_variable_store)
return EFI_UNSUPPORTED;
return fops->query_variable_store(attributes, size);
}
static efi_status_t
check_var_size(struct efivars *efivars, u32 attributes, unsigned long size)
{
efi_status_t status;
unsigned long flags;
spin_lock_irqsave(&efivars->lock, flags);
status = check_var_size_locked(efivars, attributes, size);
spin_unlock_irqrestore(&efivars->lock, flags);
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(entry->efivars, var);
if (status != EFI_SUCCESS)
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;
efi_status_t status;
if (!entry || !buf)
return -EINVAL;
status = get_var_data(entry->efivars, 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(entry->efivars, 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;
struct efivars *efivars = entry->efivars;
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;
}
if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
printk(KERN_ERR "efivars: Malformed variable content\n");
return -EINVAL;
}
spin_lock_irq(&efivars->lock);
status = check_var_size_locked(efivars, new_var->Attributes,
new_var->DataSize + ucs2_strsize(new_var->VariableName, 1024));
if (status == EFI_SUCCESS || status == EFI_UNSUPPORTED)
status = efivars->ops->set_variable(new_var->VariableName,
&new_var->VendorGuid,
new_var->Attributes,
new_var->DataSize,
new_var->Data);
spin_unlock_irq(&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(entry->efivars, 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 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_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 = -EIO;
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;
struct efivars *efivars;
efi_status_t status;
void *data;
u32 attributes;
struct inode *inode = file->f_mapping->host;
unsigned long datasize = count - sizeof(attributes);
unsigned long newdatasize, varsize;
ssize_t bytes = 0;
if (count < sizeof(attributes))
return -EINVAL;
if (copy_from_user(&attributes, userbuf, sizeof(attributes)))
return -EFAULT;
if (attributes & ~(EFI_VARIABLE_MASK))
return -EINVAL;
efivars = var->efivars;
/*
* Ensure that the user can't allocate arbitrarily large
* amounts of memory. Pick a default size of 64K if
* QueryVariableInfo() isn't supported by the firmware.
*/
varsize = datasize + ucs2_strsize(var->var.VariableName, 1024);
status = check_var_size(efivars, attributes, varsize);
if (status != EFI_SUCCESS) {
if (status != EFI_UNSUPPORTED)
return efi_status_to_err(status);
if (datasize > 65536)
return -ENOSPC;
}
data = kmalloc(datasize, GFP_KERNEL);
if (!data)
return -ENOMEM;
if (copy_from_user(data, userbuf + sizeof(attributes), datasize)) {
bytes = -EFAULT;
goto out;
}
if (validate_var(&var->var, data, datasize) == false) {
bytes = -EINVAL;
goto out;
}
/*
* 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_locked(efivars, attributes, varsize);
if (status != EFI_SUCCESS && status != EFI_UNSUPPORTED) {
spin_unlock_irq(&efivars->lock);
kfree(data);
return efi_status_to_err(status);
}
status = efivars->ops->set_variable(var->var.VariableName,
&var->var.VendorGuid,
attributes, datasize,
data);
if (status != EFI_SUCCESS) {
spin_unlock_irq(&efivars->lock);
kfree(data);
return efi_status_to_err(status);
}
bytes = count;
/*
* 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.
*/
newdatasize = 0;
status = efivars->ops->get_variable(var->var.VariableName,
&var->var.VendorGuid,
NULL, &newdatasize,
NULL);
if (status == EFI_BUFFER_TOO_SMALL) {
spin_unlock_irq(&efivars->lock);
mutex_lock(&inode->i_mutex);
i_size_write(inode, newdatasize + sizeof(attributes));
mutex_unlock(&inode->i_mutex);
} else if (status == EFI_NOT_FOUND) {
list_del(&var->list);
spin_unlock_irq(&efivars->lock);
efivar_unregister(var);
drop_nlink(inode);
d_delete(file->f_dentry);
dput(file->f_dentry);
} else {
spin_unlock_irq(&efivars->lock);
pr_warn("efivarfs: inconsistent EFI variable implementation? "
"status = %lx\n", status);
}
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;
struct efivars *efivars = var->efivars;
efi_status_t status;
unsigned long datasize = 0;
u32 attributes;
void *data;
ssize_t size = 0;
spin_lock_irq(&efivars->lock);
status = efivars->ops->get_variable(var->var.VariableName,
&var->var.VendorGuid,
&attributes, &datasize, NULL);
spin_unlock_irq(&efivars->lock);
if (status != EFI_BUFFER_TOO_SMALL)
return efi_status_to_err(status);
data = kmalloc(datasize + sizeof(attributes), GFP_KERNEL);
if (!data)
return -ENOMEM;
spin_lock_irq(&efivars->lock);
status = efivars->ops->get_variable(var->var.VariableName,
&var->var.VendorGuid,
&attributes, &datasize,
(data + sizeof(attributes)));
spin_unlock_irq(&efivars->lock);
if (status != EFI_SUCCESS) {
size = efi_status_to_err(status);
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[GUID_LEN] = {
[8] = 1, [13] = 1, [18] = 1, [23] = 1
};
const char *s = str + len - GUID_LEN;
int i;
/*
* We need a GUID, plus at least one letter for the variable name,
* plus the '-' separator
*/
if (len < 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 < 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 efivars *efivars = &__efivars;
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 - 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;
var->efivars = efivars;
var->kobj.kset = efivars->kset;
err = kobject_init_and_add(&var->kobj, &efivar_ktype, NULL, "%s",
dentry->d_name.name);
if (err)
goto out;
kobject_uevent(&var->kobj, KOBJ_ADD);
spin_lock_irq(&efivars->lock);
list_add(&var->list, &efivars->list);
spin_unlock_irq(&efivars->lock);
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;
struct efivars *efivars = var->efivars;
efi_status_t status;
spin_lock_irq(&efivars->lock);
status = efivars->ops->set_variable(var->var.VariableName,
&var->var.VendorGuid,
0, 0, NULL);
if (status == EFI_SUCCESS || status == EFI_NOT_FOUND) {
list_del(&var->list);
spin_unlock_irq(&efivars->lock);
efivar_unregister(var);
drop_nlink(dentry->d_inode);
dput(dentry);
return 0;
}
spin_unlock_irq(&efivars->lock);
return -EINVAL;
};
/*
* 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 - 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, 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-- > 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_fill_super(struct super_block *sb, void *data, int silent)
{
struct inode *inode = NULL;
struct dentry *root;
struct efivar_entry *entry, *n;
struct efivars *efivars = &__efivars;
char *name;
int err = -ENOMEM;
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;
list_for_each_entry_safe(entry, n, &efivars->list, list) {
struct dentry *dentry, *root = efivarfs_sb->s_root;
unsigned long size = 0;
int len, i;
inode = NULL;
len = ucs2_strlen(entry->var.VariableName);
/* name, plus '-', plus GUID, plus NUL*/
name = kmalloc(len + 1 + GUID_LEN + 1, GFP_ATOMIC);
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+GUID_LEN+1] = '\0';
inode = efivarfs_get_inode(efivarfs_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);
spin_lock_irq(&efivars->lock);
efivars->ops->get_variable(entry->var.VariableName,
&entry->var.VendorGuid,
&entry->var.Attributes,
&size,
NULL);
spin_unlock_irq(&efivars->lock);
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:
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;
}
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)
{
struct efivars *efivars = psi->data;
spin_lock_irq(&efivars->lock);
efivars->walk_entry = list_first_entry(&efivars->list,
struct efivar_entry, list);
return 0;
}
static int efi_pstore_close(struct pstore_info *psi)
{
struct efivars *efivars = psi->data;
spin_unlock_irq(&efivars->lock);
return 0;
}
static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
int *count, struct timespec *timespec,
char **buf, struct pstore_info *psi)
{
efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
struct efivars *efivars = psi->data;
char name[DUMP_NAME_LEN];
int i;
int cnt;
unsigned int part, size;
unsigned long time;
while (&efivars->walk_entry->list != &efivars->list) {
if (!efi_guidcmp(efivars->walk_entry->var.VendorGuid,
vendor)) {
for (i = 0; i < DUMP_NAME_LEN; i++) {
name[i] = efivars->walk_entry->var.VariableName[i];
}
if (sscanf(name, "dump-type%u-%u-%d-%lu",
type, &part, &cnt, &time) == 4) {
*id = part;
*count = cnt;
timespec->tv_sec = time;
timespec->tv_nsec = 0;
} else if (sscanf(name, "dump-type%u-%u-%lu",
type, &part, &time) == 3) {
/*
* Check if an old format,
* which doesn't support holding
* multiple logs, remains.
*/
*id = part;
*count = 0;
timespec->tv_sec = time;
timespec->tv_nsec = 0;
} else {
efivars->walk_entry = list_entry(
efivars->walk_entry->list.next,
struct efivar_entry, list);
continue;
}
get_var_data_locked(efivars, &efivars->walk_entry->var);
size = efivars->walk_entry->var.DataSize;
*buf = kmalloc(size, GFP_KERNEL);
if (*buf == NULL)
return -ENOMEM;
memcpy(*buf, efivars->walk_entry->var.Data,
size);
efivars->walk_entry = list_entry(
efivars->walk_entry->list.next,
struct efivar_entry, list);
return size;
}
efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
struct efivar_entry, list);
}
return 0;
}
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;
struct efivars *efivars = psi->data;
int i, ret = 0;
efi_status_t status = EFI_NOT_FOUND;
unsigned long flags;
if (pstore_cannot_block_path(reason)) {
/*
* If the lock is taken by another cpu in non-blocking path,
* this driver returns without entering firmware to avoid
* hanging up.
*/
if (!spin_trylock_irqsave(&efivars->lock, flags))
return -EBUSY;
} else
spin_lock_irqsave(&efivars->lock, flags);
/*
* Check if there is a space enough to log.
* size: a size of logging data
* DUMP_NAME_LEN * 2: a maximum size of variable name
*/
status = check_var_size_locked(efivars, PSTORE_EFI_ATTRIBUTES,
size + DUMP_NAME_LEN * 2);
if (status) {
spin_unlock_irqrestore(&efivars->lock, flags);
*id = part;
return -ENOSPC;
}
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];
efivars->ops->set_variable(efi_name, &vendor, PSTORE_EFI_ATTRIBUTES,
size, psi->buf);
spin_unlock_irqrestore(&efivars->lock, flags);
if (reason == KMSG_DUMP_OOPS && efivar_wq_enabled)
schedule_work(&efivar_work);
*id = part;
return ret;
};
static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count,
struct timespec time, struct pstore_info *psi)
{
char name[DUMP_NAME_LEN];
efi_char16_t efi_name[DUMP_NAME_LEN];
char name_old[DUMP_NAME_LEN];
efi_char16_t efi_name_old[DUMP_NAME_LEN];
efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
struct efivars *efivars = psi->data;
struct efivar_entry *entry, *found = NULL;
int i;
sprintf(name, "dump-type%u-%u-%d-%lu", type, (unsigned int)id, count,
time.tv_sec);
spin_lock_irq(&efivars->lock);
for (i = 0; i < DUMP_NAME_LEN; i++)
efi_name[i] = name[i];
/*
* Clean up an entry with the same name
*/
list_for_each_entry(entry, &efivars->list, list) {
get_var_data_locked(efivars, &entry->var);
if (efi_guidcmp(entry->var.VendorGuid, vendor))
continue;
if (ucs2_strncmp(entry->var.VariableName, efi_name,
ucs2_strlen(efi_name))) {
/*
* Check if an old format,
* which doesn't support holding
* multiple logs, remains.
*/
sprintf(name_old, "dump-type%u-%u-%lu", type,
(unsigned int)id, time.tv_sec);
for (i = 0; i < DUMP_NAME_LEN; i++)
efi_name_old[i] = name_old[i];
if (ucs2_strncmp(entry->var.VariableName, efi_name_old,
ucs2_strlen(efi_name_old)))
continue;
}
/* found */
found = entry;
efivars->ops->set_variable(entry->var.VariableName,
&entry->var.VendorGuid,
PSTORE_EFI_ATTRIBUTES,
0, NULL);
break;
}
if (found)
list_del(&found->list);
spin_unlock_irq(&efivars->lock);
if (found)
efivar_unregister(found);
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(struct efivars *efivars)
{
efivars->efi_pstore_info = efi_pstore_info;
efivars->efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL);
if (efivars->efi_pstore_info.buf) {
efivars->efi_pstore_info.bufsize = 1024;
efivars->efi_pstore_info.data = efivars;
spin_lock_init(&efivars->efi_pstore_info.buf_lock);
pstore_register(&efivars->efi_pstore_info);
}
}
#else
static void efivar_pstore_register(struct efivars *efivars)
{
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 efivars *efivars = bin_attr->private;
struct efivar_entry *search_efivar, *n;
unsigned long strsize1, strsize2;
efi_status_t status = EFI_NOT_FOUND;
int found = 0;
if (!capable(CAP_SYS_ADMIN))
return -EACCES;
if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
printk(KERN_ERR "efivars: Malformed variable content\n");
return -EINVAL;
}
spin_lock_irq(&efivars->lock);
/*
* Does this variable already exist?
*/
list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
strsize1 = ucs2_strsize(search_efivar->var.VariableName, 1024);
strsize2 = ucs2_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_irq(&efivars->lock);
return -EINVAL;
}
status = check_var_size_locked(efivars, new_var->Attributes,
new_var->DataSize + ucs2_strsize(new_var->VariableName, 1024));
if (status && status != EFI_UNSUPPORTED) {
spin_unlock_irq(&efivars->lock);
return efi_status_to_err(status);
}
/* now *really* create the variable via EFI */
status = efivars->ops->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_irq(&efivars->lock);
return -EIO;
}
spin_unlock_irq(&efivars->lock);
/* Create the entry in sysfs. Locking is not required here */
status = efivar_create_sysfs_entry(efivars,
ucs2_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 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 efivars *efivars = bin_attr->private;
struct efivar_entry *search_efivar, *n;
unsigned long strsize1, strsize2;
efi_status_t status = EFI_NOT_FOUND;
int found = 0;
if (!capable(CAP_SYS_ADMIN))
return -EACCES;
spin_lock_irq(&efivars->lock);
/*
* Does this variable already exist?
*/
list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
strsize1 = ucs2_strsize(search_efivar->var.VariableName, 1024);
strsize2 = ucs2_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_irq(&efivars->lock);
return -EINVAL;
}
/* force the Attributes/DataSize to 0 to ensure deletion */
del_var->Attributes = 0;
del_var->DataSize = 0;
status = efivars->ops->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_irq(&efivars->lock);
return -EIO;
}
list_del(&search_efivar->list);
/* We need to release this lock before unregistering. */
spin_unlock_irq(&efivars->lock);
efivar_unregister(search_efivar);
/* It's dead Jim.... */
return count;
}
static bool variable_is_present(struct efivars *efivars,
efi_char16_t *variable_name,
efi_guid_t *vendor)
{
struct efivar_entry *entry, *n;
unsigned long strsize1, strsize2;
bool found = false;
strsize1 = ucs2_strsize(variable_name, 1024);
list_for_each_entry_safe(entry, n, &efivars->list, list) {
strsize2 = ucs2_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;
}
/*
* 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 efivars *efivars = &__efivars;
efi_guid_t vendor;
efi_char16_t *variable_name;
unsigned long variable_name_size = 1024;
efi_status_t status = EFI_NOT_FOUND;
bool found;
/* Add new sysfs entries */
while (1) {
variable_name = kzalloc(variable_name_size, GFP_KERNEL);
if (!variable_name) {
pr_err("efivars: Memory allocation failed.\n");
return;
}
spin_lock_irq(&efivars->lock);
found = false;
while (1) {
variable_name_size = 1024;
status = efivars->ops->get_next_variable(
&variable_name_size,
variable_name,
&vendor);
if (status != EFI_SUCCESS) {
break;
} else {
if (!variable_is_present(efivars,
variable_name, &vendor)) {
found = true;
break;
}
}
}
spin_unlock_irq(&efivars->lock);
if (!found) {
kfree(variable_name);
break;
} else {
variable_name_size = var_name_strnsize(variable_name,
variable_name_size);
efivar_create_sysfs_entry(efivars,
variable_name_size,
variable_name, &vendor);
}
}
}
/*
* 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()
* 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(struct efivars *efivars,
unsigned long variable_name_size,
efi_char16_t *variable_name,
efi_guid_t *vendor_guid)
{
int i, short_name_size;
char *short_name;
struct efivar_entry *new_efivar;
/*
* 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 + GUID_LEN + 1;
short_name = kzalloc(short_name_size, GFP_KERNEL);
new_efivar = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
if (!short_name || !new_efivar) {
kfree(short_name);
kfree(new_efivar);
return 1;
}
new_efivar->efivars = efivars;
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));
new_efivar->kobj.kset = efivars->kset;
i = kobject_init_and_add(&new_efivar->kobj, &efivar_ktype, NULL,
"%s", short_name);
if (i) {
kfree(short_name);
kfree(new_efivar);
return 1;
}
kobject_uevent(&new_efivar->kobj, KOBJ_ADD);
kfree(short_name);
short_name = NULL;
spin_lock_irq(&efivars->lock);
list_add(&new_efivar->list, &efivars->list);
spin_unlock_irq(&efivars->lock);
return 0;
}
static int
create_efivars_bin_attributes(struct efivars *efivars)
{
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;
attr->private = efivars;
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;
attr->private = efivars;
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;
}
void unregister_efivars(struct efivars *efivars)
{
struct efivar_entry *entry, *n;
list_for_each_entry_safe(entry, n, &efivars->list, list) {
spin_lock_irq(&efivars->lock);
list_del(&entry->list);
spin_unlock_irq(&efivars->lock);
efivar_unregister(entry);
}
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->kobject);
kset_unregister(efivars->kset);
}
EXPORT_SYMBOL_GPL(unregister_efivars);
/*
* 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);
}
int register_efivars(struct efivars *efivars,
const struct efivar_operations *ops,
struct kobject *parent_kobj)
{
efi_status_t status = EFI_NOT_FOUND;
efi_guid_t vendor_guid;
efi_char16_t *variable_name;
unsigned long variable_name_size = 1024;
int error = 0;
variable_name = kzalloc(variable_name_size, GFP_KERNEL);
if (!variable_name) {
printk(KERN_ERR "efivars: Memory allocation failed.\n");
return -ENOMEM;
}
spin_lock_init(&efivars->lock);
INIT_LIST_HEAD(&efivars->list);
efivars->ops = ops;
efivars->kset = kset_create_and_add("vars", NULL, parent_kobj);
if (!efivars->kset) {
printk(KERN_ERR "efivars: Subsystem registration failed.\n");
error = -ENOMEM;
goto out;
}
efivars->kobject = kobject_create_and_add("efivars", parent_kobj);
if (!efivars->kobject) {
pr_err("efivars: Subsystem registration failed.\n");
error = -ENOMEM;
kset_unregister(efivars->kset);
goto out;
}
/*
* 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:
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 (variable_is_present(efivars, variable_name,
&vendor_guid)) {
dup_variable_bug(variable_name, &vendor_guid,
variable_name_size);
status = EFI_NOT_FOUND;
break;
}
efivar_create_sysfs_entry(efivars,
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);
error = create_efivars_bin_attributes(efivars);
if (error)
unregister_efivars(efivars);
if (!efivars_pstore_disable)
efivar_pstore_register(efivars);
register_filesystem(&efivarfs_type);
out:
kfree(variable_name);
return error;
}
EXPORT_SYMBOL_GPL(register_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 = 0;
printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION,
EFIVARS_DATE);
if (!efi_enabled(EFI_RUNTIME_SERVICES))
return 0;
/* For now we'll 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;
}
ops.get_variable = efi.get_variable;
ops.set_variable = efi.set_variable;
ops.get_next_variable = efi.get_next_variable;
ops.query_variable_store = efi_query_variable_store;
error = register_efivars(&__efivars, &ops, efi_kobj);
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:
unregister_efivars(&__efivars);
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)) {
unregister_efivars(&__efivars);
kobject_put(efi_kobj);
}
}
module_init(efivars_init);
module_exit(efivars_exit);
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