- 根目录:
- drivers
- firmware
- efi
- vars.c
/*
* Originally from efivars.c
*
* Copyright (C) 2001,2003,2004 Dell <Matt_Domsch@dell.com>
* Copyright (C) 2004 Intel Corporation <matthew.e.tolentino@intel.com>
*
* This 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
*/
#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/device.h>
#include <linux/slab.h>
#include <linux/ctype.h>
#include <linux/ucs2_string.h>
/* Private pointer to registered efivars */
static struct efivars *__efivars;
static bool efivar_wq_enabled = true;
DECLARE_WORK(efivar_work, NULL);
EXPORT_SYMBOL_GPL(efivar_work);
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 },
};
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)
{
const struct efivar_operations *fops = __efivars->ops;
if (!fops->query_variable_store)
return EFI_UNSUPPORTED;
return fops->query_variable_store(attributes, size);
}
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 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 = ucs2_strsize(variable_name, 1024);
list_for_each_entry_safe(entry, n, head, 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);
}
/*
* 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);
}
/**
* 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 but leave @entry on the
* variable list.
*
* This function differs from efivar_entry_delete() because it does
* not remove @entry from the variable list. Also, 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.
*/
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);
return efi_status_to_err(status);
}
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 + ucs2_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_store)
return -ENOSYS;
if (!block) {
if (!spin_trylock_irqsave(&__efivars->lock, flags))
return -EBUSY;
} else {
spin_lock_irqsave(&__efivars->lock, flags);
}
status = check_var_size(attributes, size + ucs2_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 = ucs2_strsize(name, 1024);
strsize2 = ucs2_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) {
if (entry->scanning) {
/*
* The entry will be deleted
* after scanning is completed.
*/
entry->deleting = true;
} else
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
*/
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
*
* 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_get(struct efivar_entry *entry, u32 *attributes,
unsigned long *size, void *data)
{
const struct efivar_operations *ops = __efivars->ops;
efi_status_t status;
WARN_ON(!spin_is_locked(&__efivars->lock));
status = ops->get_variable(entry->var.VariableName,
&entry->var.VendorGuid,
attributes, size, data);
return efi_status_to_err(status);
}
EXPORT_SYMBOL_GPL(__efivar_entry_get);
/**
* 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 + ucs2_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);
/**
* efivar_run_worker - schedule the efivar worker thread
*/
void efivar_run_worker(void)
{
if (efivar_wq_enabled)
schedule_work(&efivar_work);
}
EXPORT_SYMBOL_GPL(efivar_run_worker);
/**
* 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;
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);