Merged this weekend ahead of the Linux 6.18-rc4 test kernel release due out later today is the "x86/fixes" for the week. There are a few notable changes on the x86 (x86_64) side of the kernel this week for [1]Linux 6.18 .

First up, more AMD [2]Zen 6 CPU model IDs are now recognized by the kernel as part of enabling these next-generation processors for Linux. As covered when the kernel patch was first posted, [3]AMD is now adding additional Zen 6 model IDs to the Family 1Ah . The range of recognized Zen 6 model IDs is now expanded by 16 to make way in advance for more potential Zen 6 based products.

Also on the AMD side is disabling RDSEED use on select Zen 5 CPUs with older microcode where there's that previously talked about RDSEED bug. Reported a few weeks back was [4]a Zen 5 architectural issue with RDSEED usage for RNG seeding. This week [5]AMD acknowledged the RDSEED issue and has a microcode/AGESA fix coming with the updated AMD EPYC 9005 microcode already shipping while software updates for other hardware will be out in the coming weeks.

Linux 6.18-rc4 is disabling RDSEED on affected Zen 5 CPUs with microcode version prior to that fix being applied. Separately, the x86/fixes pull also has a fix for AMD FPU XFD state synchronization on signal delivery.

The pull also has a fix for kernel builds with CONFIG_CFI=y and CONFIG_LTO_CLANG_FULL=y to avoid build failures.

More details on this week's x86/fixes via [6]this pull request with those patches having now been merged to Linux Git ahead of Linux 6.18-rc4 coming out later today.



[1] https://www.phoronix.com/search/Linux+6.18

[2] https://www.phoronix.com/search/Zen+6

[3] https://www.phoronix.com/news/Linux-Patch-More-Zen-6-Models

[4] https://www.phoronix.com/news/AMD-EPYC-Turin-RDSEED-Bug

[5] https://www.phoronix.com/news/AMD-SB-7055-RDSEED-Zen-5

[6] https://lore.kernel.org/lkml/aQW2Imsfgixz_jBc@gmail.com/