One new feature in UEFI 2.5 is the ESRT (EFI System Resource Table). As reported in Phoronix, ESRT supports has been added to the Linux kernel, and it appears that it’ll be in Linux 4.2. Quoting Peter Jones’ ESRT patch to sysfs on the linux-efi list, describing ESRT:
“The EFI System Resource Table (ESRT) provides a read-only catalog of system components for which the system accepts firmware upgrades via UEFI’s “Capsule Update” feature. This module allows userland utilities to evaluate what firmware updates can be applied to this system, and potentially arrange for those updates to occur. The ESRT is described as part of the UEFI specification, in version 2.5 which should be available from http://uefi.org/specifications in early 2015. If you’re a member of the UEFI Forum, information about its addition to the standard is available as UEFI Mantis 1090. For some hardware platforms, additional restrictions may be found at http://msdn.microsoft.com/en-us/library/windows/hardware/jj128256.aspx , and additional documentation may be found at http://download.microsoft.com/download/5/F/5/5F5D16CD-2530-4289-8019-94C6A20BED3C/windows-uefi-firmware-update-platform.docx .”
Peter’s patch adds sysfs files for the EFI System Resource Table (ESRT) under /sys/firmware/efi/esrt and for each EFI System Resource Entry under entries/ as a subdir. See the UEFI 2.5 specification for more details on ESRT.