Linux 6.1 POWERs Up With KFENCE, Syscall Wrappers, Execute-Only Memory

The IBM POWER/PowerPC changes were merged this week for the Linux 6.1 kernel with this cycle's merge window closing later today.

While POWER9 was quite popular with many Linux/open-source enthusiasts due to the open nature of these IBM processors and Raptor Computing Systems doing a wonderful job with some "libre" POWER9 systems from the Blackbird micro-ATX board up through the high-end Talos II server, right now with IBM's latest generation POWER10 hardware it's sadly a dud from this perspective. POWER10 having various firmware blobs and very expensive POWER10 motherboards making these new processors a non-starter for Raptor right now. So for free software purists and enthusiasts looking for decent-priced POWER10 hardware, sadly there is no option right now. In any event, POWER9 remains available and from the kernel side there continues to be various software improvements.

Raptor Blackbird POWER9 while nice is sadly without any modern POWER10-based option yet.

The PowerPC updates for Linux 6.1 include adding KFENCE support for the 64-bit kernel, support for system call wrappers, the 64-bit HV KVM implementation switches to a new accounting API, support for execute-only memory, allow for VDSO randomization on 32-bit, and various other changes. KFENCE was mainlined in the Linux kernel last year as a low-overhead memory safety feature, which with Linux 6.1 can now also work on 64-bit POWER kernel builds. The execute-only memory support is limited to POWER9 CPUs and newer with the Radix MMU.

The full list of changes with this pull request can be found on the LKML.