1What:		/sys/firmware/secvar
  2Date:		August 2019
  3Contact:	Nayna Jain <nayna@linux.ibm.com>
  4Description:	This directory is created if the POWER firmware supports OS
  5		secureboot, thereby secure variables. It exposes interface
  6		for reading/writing the secure variables
  7
  8What:		/sys/firmware/secvar/vars
  9Date:		August 2019
 10Contact:	Nayna Jain <nayna@linux.ibm.com>
 11Description:	This directory lists all the secure variables that are supported
 12		by the firmware.
 13
 14What:		/sys/firmware/secvar/format
 15Date:		August 2019
 16Contact:	Nayna Jain <nayna@linux.ibm.com>
 17Description:	A string indicating which backend is in use by the firmware.
 18		This determines the format of the variable and the accepted
 19		format of variable updates.
 20
 21		On powernv/OPAL, this value is provided by the OPAL firmware
 22		and is expected to be "ibm,edk2-compat-v1".
 23
 24		On pseries/PLPKS, this is generated by the kernel based on the
 25		version number in the SB_VERSION variable in the keystore, and
 26		has the form "ibm,plpks-sb-v<version>", or
 27		"ibm,plpks-sb-unknown" if there is no SB_VERSION variable.
 28
 29What:		/sys/firmware/secvar/vars/<variable name>
 30Date:		August 2019
 31Contact:	Nayna Jain <nayna@linux.ibm.com>
 32Description:	Each secure variable is represented as a directory named as
 33		<variable_name>. The variable name is unique and is in ASCII
 34		representation. The data and size can be determined by reading
 35		their respective attribute files.
 36
 37What:		/sys/firmware/secvar/vars/<variable_name>/size
 38Date:		August 2019
 39Contact:	Nayna Jain <nayna@linux.ibm.com>
 40Description:	An integer representation of the size of the content of the
 41		variable. In other words, it represents the size of the data.
 42
 43What:		/sys/firmware/secvar/vars/<variable_name>/data
 44Date:		August 2019
 45Contact:	Nayna Jain <nayna@linux.ibm.com>
 46Description:	A read-only file containing the value of the variable. The size
 47		of the file represents the maximum size of the variable data.
 48
 49What:		/sys/firmware/secvar/vars/<variable_name>/update
 50Date:		August 2019
 51Contact:	Nayna Jain <nayna@linux.ibm.com>
 52Description:	A write-only file that is used to submit the new value for the
 53		variable. The size of the file represents the maximum size of
 54		the variable data that can be written.
 55
 56What:		/sys/firmware/secvar/config
 57Date:		February 2023
 58Contact:	Nayna Jain <nayna@linux.ibm.com>
 59Description:	This optional directory contains read-only config attributes as
 60		defined by the secure variable implementation.  All data is in
 61		ASCII format. The directory is only created if the backing
 62		implementation provides variables to populate it, which at
 63		present is only PLPKS on the pseries platform.
 64
 65What:		/sys/firmware/secvar/config/version
 66Date:		February 2023
 67Contact:	Nayna Jain <nayna@linux.ibm.com>
 68Description:	Config version as reported by the hypervisor in ASCII decimal
 69		format.
 70
 71		Currently only provided by PLPKS on the pseries platform.
 72
 73What:		/sys/firmware/secvar/config/max_object_size
 74Date:		February 2023
 75Contact:	Nayna Jain <nayna@linux.ibm.com>
 76Description:	Maximum allowed size of	objects in the keystore in bytes,
 77		represented in ASCII decimal format.
 78
 79		This is not necessarily the same as the max size that can be
 80		written to an update file as writes can contain more than
 81		object data, you should use the size of the update file for
 82		that purpose.
 83
 84		Currently only provided by PLPKS on the pseries platform.
 85
 86What:		/sys/firmware/secvar/config/total_size
 87Date:		February 2023
 88Contact:	Nayna Jain <nayna@linux.ibm.com>
 89Description:	Total size of the PLPKS in bytes, represented in ASCII decimal
 90		format.
 91
 92		Currently only provided by PLPKS on the pseries platform.
 93
 94What:		/sys/firmware/secvar/config/used_space
 95Date:		February 2023
 96Contact:	Nayna Jain <nayna@linux.ibm.com>
 97Description:	Current space consumed by the key store, in bytes, represented
 98		in ASCII decimal format.
 99
100		Currently only provided by PLPKS on the pseries platform.
101
102What:		/sys/firmware/secvar/config/supported_policies
103Date:		February 2023
104Contact:	Nayna Jain <nayna@linux.ibm.com>
105Description:	Bitmask of supported policy flags by the hypervisor,
106		represented as an 8 byte hexadecimal ASCII string. Consult the
107		hypervisor documentation for what these flags are.
108
109		Currently only provided by PLPKS on the pseries platform.
110
111What:		/sys/firmware/secvar/config/signed_update_algorithms
112Date:		February 2023
113Contact:	Nayna Jain <nayna@linux.ibm.com>
114Description:	Bitmask of flags indicating which algorithms the hypervisor
115		supports for signed update of objects, represented as a 16 byte
116		hexadecimal ASCII string. Consult the hypervisor documentation
117		for what these flags mean.
118
119		Currently only provided by PLPKS on the pseries platform.