Intel's FRED Looks Like It Could Be Ready For Linux 6.9

For the better part of two years we've seen Intel open-source software engineers working on preparing the Linux kernel for FRED, the Flexible Return and Event Delivery for defining new transitions for changing privilege levels. Intel's been working hard on the FRED kernel plumbing for better performance, lower response times, and improved robustness and it's looking like FRED could be set to land come Linux 6.9.

There's been the Linux kernel patches for FRED since 2022 and related to that have been the Intel LKGS support as the new Load Kernel GS instruction. Outside of the kernel there's been the toolchain changes around FRED/LKGS too.

The FRED specification can be found on Intel.com for those interested.

It looks like Intel's enablement on FRED for overhauling handling between privilege levels / CPU rings could cross the initial line in Linux 6.9. Created today was the x86/fred branch in tip/tip.git. With the Intel FRED patches hitting a tip/tip.git branch, it's likely to be submitted to the kernel soon -- potentially for the Linux 6.9 merge window that will be coming up in about two months.

Intel hasn't outlined when FRED will make its processor debut, but with the upstreaming to the mainline Linux kernel only coming up in the months ahead and given Intel's typical Linux support being well in advance of product launches, it's likely around the Lunar Lake ~ Clearwater Forest timeframe next year that perhaps we'll see FRED in use.