Linux 4.11 Adds EFI Memory Attributes Table Support
Written by Michael Larabel in Linux Kernel on 21 February 2017 at 09:27 AM EST. 19 Comments
LINUX KERNEL --
The (U)EFI support continues to evolve within the Linux kernel and with the 4.11 release will be new and improved functionality.

Linux 4.11 EFI changes include changes to the initialization code for checking accurately if secure boot authentication was performed at boot time, support for UEFI memory attributes table on x86, and other changes and bug fixes.

The EFI_MEMORY_ATTRIBUTES_TABLE support in Linux 4.11 for x86 EFI was described by developer Sai Praneeth Prakhya in his patch, "UEFI v2.6 introduces EFI_MEMORY_ATTRIBUTES_TABLE which describes memory protections that may be applied to EFI Runtime code and data regions by kernel. This enables kernel to map these regions more strictly thereby increasing security. Presently, the only valid bits for attribute field of a memory descriptor are EFI_MEMORY_RO and EFI_MEMORY_XP, hence use these bits to update mappings in efi_pgd."

Thus this benefits newer systems with UEFI 2.6+ with being able to accurately apply memory protections to the UEFI Runtime code and data regions and this new EFI_MEMORY_ATTRIBUTES_TABLE support is used in place of EFI_PROPERTIES_TABLE, but that is still supported as a fallback for older UEFI systems.

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Michael Larabel is the principal author of Phoronix.com and founded the site in 2004 with a focus on enriching the Linux hardware experience. Michael has written more than 10,000 articles covering the state of Linux hardware support, Linux performance, graphics drivers, and other topics. Michael is also the lead developer of the Phoronix Test Suite, Phoromatic, and OpenBenchmarking.org automated benchmarking software. He can be followed via Twitter or contacted via MichaelLarabel.com.

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