Benchmarking The Performance Impact Of Linux 5.15's Newest Protection Around Side Channel Attacks

With the in-development Linux 5.15 kernel there is a new option for further protecting the kernel around side channel attacks and information leakage. Enabling the option will ensure that any caller-used register contents are zeroed prior to returning from a function. While the reported performance cost is said to be small, I decided to run some benchmarks when toggling this new Kconfig hardening option.