http://cypherpunk-handbook.i2p/articles/openbsd.html
When a system call happens, we check to see
if the stack-pointer register points to such a page. If not, the
program is killed. The ABI is tighter as a result. You may no longer
point your stack register at non-stack memory, or your program will
die. macOS, Windows, and Linux: No. 36 - Swap encryption by default To protect sensitive information such as passwords from leaking to
disk, where they can persist for many years.