Linux 6.12 To Support Arm's Permission Overlay Extension

The 64-bit ARM changes were submitted in advance for the now-open Linux 6.12 kernel merge window. There is work for Arm on the confidential computing side this cycle and other new features.

With Linux 6.12 the Arm Permission Overlay Extension support is finally baked after being in development for the kernel the past year. Arm's Permission Overlay Extension was added to the Arm A-Profile specs in 2022. Permission Overlay Extension provides the ability to constrain permissions on memory regions and can be used from user-space. With the Arm Permission Overlay Extension support it's used to implement the Linux Memory Protection Keys system call support.

Linux 6.12 on the Arm confidential computing side adds support for booting an ARM64 kernel as a protected guest under Android's Protected KVM "pKVM" hypervisor.

Other ARM64 changes for Linux 6.12 include erratum workarounds for HiSilicon and AmpereOne platforms, a crash fix for the AMDGPU driver on AMD64, and a variety of other fixes.

More details on the ARM64 architecture changes for Linux 6.12 via the pull request.