AMD Bus Lock Detect Positioned Ahead Of Linux 6.12

Going back four years ago Intel engineers worked out bus lock detection for the Linux kernel to benefit their processors able to detect bus locks and then notify the kernel, given the negative performance implications associated with bus locks. That Intel support was merged in Linux 5.13 back in 2021 while now AMD has their equivalent ready for mainlining in the Linux kernel.

The Linux kernel bus lock detection is being extended to support AMD's Bus Lock Trap feature being introduced with the Zen 5 processors.With AMD Bus Lock Trap, a #DB exception is raised when a bus lock occurs.

AMD Linux engineers have had their Bus Lock Detect / Bus Lock Trap patches out for a few months while the code has now been queued into TIP/TIP.GIT's x86/splitlock Git branch. With the AMD support working its way into a TIP branch, it should be submitted for the upcoming Linux 6.12 merge window opening in mid-September.

The AMD Bus Lock Trap support for Linux re-uses the infrastructure established by Intel with their Bus Lock Detect code and now sharing the same X86_BUS_LOCK_DETECT Kconfig option and related code.