/* * Originally from efivars.c * * Copyright (C) 2001,2003,2004 Dell * Copyright (C) 2004 Intel Corporation * * 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 #include #include #include #include #include #include #include #include #include #include #include #include #include /* 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) 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);