[$] Support for Intel's LASS

Speculative-execution vulnerabilities come about when the CPU, while executingspeculatively, is able to access memory that would otherwise be denied toit. Most of these vulnerabilities would go away if the CPU were alwaysconstrained by the established memory protections. An obvious way to fixthese problems would be to make CPUs behave that way, but doing thatwithout destroying performance is not an easy task. So, instead, Intelhas developed a feature called "linear address-space separation" (LASS) topaper over parts of the problem; Yian Chen has posted apatch set adding support for this feature.