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		attributes:	A read-only text file enumerating the
21				EFI variable flags.  Potential values
22				include:
23
24				EFI_VARIABLE_NON_VOLATILE
25				EFI_VARIABLE_BOOTSERVICE_ACCESS
26				EFI_VARIABLE_RUNTIME_ACCESS
27				EFI_VARIABLE_HARDWARE_ERROR_RECORD
28				EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS
29
30				See the EFI documentation for an
31				explanation of each of these variables.
32
33		data:		A read-only binary file that can be read
34				to attain the value of the EFI variable
35
36		guid:		The vendor GUID of the variable.  This
37				should always match the GUID in the
38				variable's name.
39
40		raw_var:	A binary file that can be read to obtain
41				a structure that contains everything
42				there is to know about the variable.
43				For structure definition see "struct
44				efi_variable" in the kernel sources.
45
46				This file can also be written to in
47				order to update the value of a variable.
48				For this to work however, all fields of
49				the "struct efi_variable" passed must
50				match byte for byte with the structure
51				read out of the file, save for the value
52				portion.
53
54				**Note** the efi_variable structure
55				read/written with this file contains a
56				'long' type that may change widths
57				depending on your underlying
58				architecture.
59
60		size:		As ASCII representation of the size of
61				the variable's value.
62
63
64		In addition, two other magic binary files are provided
65		in the top-level directory and are used for adding and
66		removing variables:
67
68		new_var:	Takes a "struct efi_variable" and
69				instructs the EFI firmware to create a
70				new variable.
71
72		del_var:	Takes a "struct efi_variable" and
73				instructs the EFI firmware to remove any
74				variable that has a matching vendor GUID
75				and variable key name.
76