Going back four years ago Intel engineers worked out [1]bus lock detection for the Linux kernel to benefit their processors able to detect bus locks and then notify the kernel, given [2]the negative performance implications associated with bus locks. That Intel support was [3]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 [4]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 [5]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.



[1] https://www.phoronix.com/news/Intel-Bus-Lock-Detection-RFC

[2] https://www.phoronix.com/news/Intel-Bus-Lock-Detection-2021

[3] https://www.phoronix.com/news/Linux-5.13-Lands-Intel-Bus-Lock

[4] https://www.phoronix.com/news/AMD-Bus-Lock-Trap-Detect-Linux

[5] https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?h=x86/splitlock&id=408eb7417a92c5354c7be34f7425b305dfe30ad9