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Based on kernel version 3.15.4. Page generated on 2014-07-07 08:59 EST.

1	What:		/sys/firmware/efi/vars
2	Date:		April 2004
3	Contact:	Matt Domsch <Matt_Domsch@dell.com>
4	Description:
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.
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