[3] Operating systems can block these exploits by using SMAP to force unintended user-space memory accesses to trigger page faults.
Additionally, SMAP can expose flawed kernel code which does not follow the intended procedures for accessing user-space memory.
[1] It was merged into the mainline Linux 3.7 kernel (released December 2012) and it is enabled by default for processors which support the feature.
[9] NetBSD support for Supervisor Mode Execution Prevention (SMEP) was implemented by Maxime Villard in December 2015.
[12] Haiku support for Supervisor Mode Execution Prevention (SMEP) was implemented by Jérôme Duval in January 2018.