Add clac/stac instructions for SMAP#108
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See https://lwn.net/Articles/517475/ for more information about Supervisor Mode Access Prevention (SMAP): "Intel has defined a separate "AC" flag that controls the SMAP feature. If the AC flag is set, SMAP protection is in force; otherwise access to user- space memory is allowed. Two new instructions (STAC and CLAC) are provided to manipulate that flag relatively quickly." This adds support for those two instructions.
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See https://lwn.net/Articles/517475/ for more information about Supervisor
Mode Access Prevention (SMAP):
"Intel has defined a separate "AC" flag that controls the SMAP feature. If
the AC flag is set, SMAP protection is in force; otherwise access to user-
space memory is allowed. Two new instructions (STAC and CLAC) are provided
to manipulate that flag relatively quickly."
This adds support for those two instructions.
http://www.felixcloutier.com/x86/STAC.html