Covered first on Phoronix back in June was an AMD Linux patch for introducing a new "low power" CPU core type to complement their typical "performance" cores and their "efficiency" cores like with Zen 4C/5C. That low power core is presumed for some Zen 6 clients and that integration is now merged for Linux 7.3 as well as unifying the Intel/AMD CPU core type handling.

The x86/cpu pull request was merged yesterday for the Linux 7.3 merge window. It adds in the "AMD_CPU_TYPE_LOW_POWER" for recognizing that upcoming low-power core rather than being an "unknown" core.

Along with that new core type, Linux 7.3 now unifies the handling of the CPU core types by mapping vendor-specific core types to now generic CPU core types. This unified/generic handling of CPU core types came up as a result of the Sashiko AI bot noting confusion among CPU core type number differences.

In addition to that x86 CPU core type identification work, also submitted and merged already are the x86/core changes . The work there includes a minor optimization for AMD Athlon XP era systems where the CPU supports SSE but not SSE2 for making use of the SFENCE instruction in the write memory barrier kernel code. That pull request also includes a KCFI optimization to benefit older Intel CPUs .

Another x86 change merged for Linux 7.3 are the MSR updates to stop using the 32-bit MSR interfaces in favor of the 64-bit interfaces to simplify the code. The 32-bit model specific register interfaces are expected to be dropped for the Linux 7.4 cycle.