linux/drivers/firmware/efi/vars.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * Originally from efivars.c
 *
 * Copyright (C) 2001,2003,2004 Dell <[email protected]>
 * Copyright (C) 2004 Intel Corporation <[email protected]>
 */

#define pr_fmt(fmt) …

#include <linux/types.h>
#include <linux/sizes.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/string.h>
#include <linux/smp.h>
#include <linux/efi.h>
#include <linux/ucs2_string.h>

/* Private pointer to registered efivars */
static struct efivars *__efivars;

static DEFINE_SEMAPHORE(efivars_lock, 1);

static efi_status_t check_var_size(bool nonblocking, u32 attributes,
				   unsigned long size)
{ … }

/**
 * efivar_is_available - check if efivars is available
 *
 * @return true iff evivars is currently registered
 */
bool efivar_is_available(void)
{ … }
EXPORT_SYMBOL_GPL(…);

/**
 * efivars_register - register an efivars
 * @efivars: efivars to register
 * @ops: efivars operations
 *
 * Only a single efivars can be registered at any time.
 */
int efivars_register(struct efivars *efivars,
		     const struct efivar_operations *ops)
{ … }
EXPORT_SYMBOL_GPL(…);

/**
 * 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)
{ … }
EXPORT_SYMBOL_GPL(…);

bool efivar_supports_writes(void)
{ … }
EXPORT_SYMBOL_GPL(…);

/*
 * efivar_lock() - obtain the efivar lock, wait for it if needed
 * @return 0 on success, error code on failure
 */
int efivar_lock(void)
{ … }
EXPORT_SYMBOL_NS_GPL(…);

/*
 * efivar_lock() - obtain the efivar lock if it is free
 * @return 0 on success, error code on failure
 */
int efivar_trylock(void)
{ … }
EXPORT_SYMBOL_NS_GPL(…);

/*
 * efivar_unlock() - release the efivar lock
 */
void efivar_unlock(void)
{ … }
EXPORT_SYMBOL_NS_GPL(…);

/*
 * efivar_get_variable() - retrieve a variable identified by name/vendor
 *
 * Must be called with efivars_lock held.
 */
efi_status_t efivar_get_variable(efi_char16_t *name, efi_guid_t *vendor,
				 u32 *attr, unsigned long *size, void *data)
{ … }
EXPORT_SYMBOL_NS_GPL(…);

/*
 * efivar_get_next_variable() - enumerate the next name/vendor pair
 *
 * Must be called with efivars_lock held.
 */
efi_status_t efivar_get_next_variable(unsigned long *name_size,
				      efi_char16_t *name, efi_guid_t *vendor)
{ … }
EXPORT_SYMBOL_NS_GPL(…);

/*
 * efivar_set_variable_locked() - set a variable identified by name/vendor
 *
 * Must be called with efivars_lock held. If @nonblocking is set, it will use
 * non-blocking primitives so it is guaranteed not to sleep.
 */
efi_status_t efivar_set_variable_locked(efi_char16_t *name, efi_guid_t *vendor,
					u32 attr, unsigned long data_size,
					void *data, bool nonblocking)
{ … }
EXPORT_SYMBOL_NS_GPL(…);

/*
 * efivar_set_variable() - set a variable identified by name/vendor
 *
 * Can be called without holding the efivars_lock. Will sleep on obtaining the
 * lock, or on obtaining other locks that are needed in order to complete the
 * call.
 */
efi_status_t efivar_set_variable(efi_char16_t *name, efi_guid_t *vendor,
				 u32 attr, unsigned long data_size, void *data)
{ … }
EXPORT_SYMBOL_NS_GPL(…);

efi_status_t efivar_query_variable_info(u32 attr,
					u64 *storage_space,
					u64 *remaining_space,
					u64 *max_variable_size)
{ … }
EXPORT_SYMBOL_NS_GPL(…);