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 21What: /sys/firmware/secvar/vars/<variable name> 22Date: August 2019 23Contact: Nayna Jain <nayna@linux.ibm.com> 24Description: Each secure variable is represented as a directory named as 25 <variable_name>. The variable name is unique and is in ASCII 26 representation. The data and size can be determined by reading 27 their respective attribute files. 28 29What: /sys/firmware/secvar/vars/<variable_name>/size 30Date: August 2019 31Contact: Nayna Jain <nayna@linux.ibm.com> 32Description: An integer representation of the size of the content of the 33 variable. In other words, it represents the size of the data. 34 35What: /sys/firmware/secvar/vars/<variable_name>/data 36Date: August 2019 37Contact: Nayna Jain h<nayna@linux.ibm.com> 38Description: A read-only file containing the value of the variable. The size 39 of the file represents the maximum size of the variable data. 40 41What: /sys/firmware/secvar/vars/<variable_name>/update 42Date: August 2019 43Contact: Nayna Jain <nayna@linux.ibm.com> 44Description: A write-only file that is used to submit the new value for the 45 variable. The size of the file represents the maximum size of 46 the variable data that can be written. 47