1What:		/sys/firmware/efi/vars
2Date:		April 2004
3Contact:	Matt Domsch <Matt_Domsch@dell.com>
4Description:
5		This directory exposes interfaces for interactive with
6		EFI variables.  For more information on EFI variables,
7		see 'Variable Services' in the UEFI specification
8		(section 7.2 in specification version 2.3 Errata D).
9
10		In summary, EFI variables are named, and are classified
11		into separate namespaces through the use of a vendor
12		GUID.  They also have an arbitrary binary value
13		associated with them.
14
15		The efivars module enumerates these variables and
16		creates a separate directory for each one found.  Each
17		directory has a name of the form "<key>-<vendor guid>"
18		and contains the following files:
19
20		=============== ========================================
21		attributes:	A read-only text file enumerating the
22				EFI variable flags.  Potential values
23				include:
24
25				EFI_VARIABLE_NON_VOLATILE
26				EFI_VARIABLE_BOOTSERVICE_ACCESS
27				EFI_VARIABLE_RUNTIME_ACCESS
28				EFI_VARIABLE_HARDWARE_ERROR_RECORD
29				EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS
30
31				See the EFI documentation for an
32				explanation of each of these variables.
33
34		data:		A read-only binary file that can be read
35				to attain the value of the EFI variable
36
37		guid:		The vendor GUID of the variable.  This
38				should always match the GUID in the
39				variable's name.
40
41		raw_var:	A binary file that can be read to obtain
42				a structure that contains everything
43				there is to know about the variable.
44				For structure definition see "struct
45				efi_variable" in the kernel sources.
46
47				This file can also be written to in
48				order to update the value of a variable.
49				For this to work however, all fields of
50				the "struct efi_variable" passed must
51				match byte for byte with the structure
52				read out of the file, save for the value
53				portion.
54
55				**Note** the efi_variable structure
56				read/written with this file contains a
57				'long' type that may change widths
58				depending on your underlying
59				architecture.
60
61		size:		As ASCII representation of the size of
62				the variable's value.
63		=============== ========================================
64
65
66		In addition, two other magic binary files are provided
67		in the top-level directory and are used for adding and
68		removing variables:
69
70		=============== ========================================
71		new_var:	Takes a "struct efi_variable" and
72				instructs the EFI firmware to create a
73				new variable.
74
75		del_var:	Takes a "struct efi_variable" and
76				instructs the EFI firmware to remove any
77				variable that has a matching vendor GUID
78				and variable key name.
79		=============== ========================================
80