AMD Makes Some Interesting SMCA Driver Changes For Future CPUs

AMD is preparing updates to their SMCA (Scalable Machine Check Architecture) driver code for future CPUs and points to processors having different bank layouts between CPU cores on the package.

A set of three patches sent out by AMD last week add new SMCA bank types in preparation for new CPUs and also bank layout changes for future AMD systems. What makes these patches interesting is, "Future AMD systems will have different bank type layouts between logical CPUs. So having a single system-wide cache of the layout won't be correct....Future AMD systems will lay out MCA bank types such that the type of bank number may be different across CPUs."

The patches though don't elaborate though on why future AMD CPUs may begin seeing different bank layouts between the logical cores of the system. It is a real possibility though that it's in relation to a hybrid processor design with a combination of different cores, similar to Alder Lake / Arm big.LITTLE. AMD patents over the past two years along with rumors have alleged AMD is developing such a hybrid processor and that could be one explanation for why future AMD CPUs may be seeing the different bank layouts between cores.

When it comes to the new SMCA bank types added for future processors as part of this same patch series. the additions include: MPDMA unit, NBIF unit, system hub unit, SATA unit, USB unit, GMI PCS unit, and GMI PHY unit.

These latest AMD machine check error driver patches can be found on the kernel mailing list as they work their way towards the mainline Linux kernel.