Linux 6.0 Adds EFI Mirrored Memory & ACPI PRM For 64-bit Arm

The EFI changes were merged last week for the Linux 6.0 cycle and contain two notable improvements on the ARM64 side.

First up, it contains the work from earlier this year posted by Huawei for UEFI mirrored memory support on ARM64. UEFI mirrored memory has worked on x86/x86_64 Linux for a number of years while now it will work on AArch64 hardware too.

UEFI allows setting up address range based partial memory mirroring and can be used for redundancy/reliability purposes on servers. AArch64 hardware meeting the UEFI spec will be able to make use of it on Linux 6.0+ now that the kernel side support is prepared.

In addition to ARM64 mirrored memory, ACPI PRM is now supported on ARM64 with Linux 6.0. This ACPI Platform Runtime Mechanism support is for exposing a set of binary executables that can be called from the AML interpreter. Having this ACPI PRM support enabled on ARM64 servers will reduce the computational overhead for system initialization on some server platforms.

Aside from those ARM64 additions, the EFI changes for Linux 6.0 are light and the full list of patches can be found via this Git merge.