Where MCP = Maximum Controlled Priority
This commit adds:
* seL4_TCB_SetMCPriority
and changes the arguments to
* seL4_TCB_Configure
As of this commit, a thread cannot create or set a threads
priority (including itself) above its mcp. Previously the kernel
did this check against a threads priority, which prevented a thread
from setting it's own priority down and then up again.
Previously the return value of cap_get_capPtr was compared to 0 in
sameRegionAs to emulate a check in the abstract specification that
tests if the cap is a physical cap or not. Overloading 0 results
in a scenario where a legitimate deviceUntyped's children do not
get considered to be children because they have a capPtr of 0.
This change adds and explicit function that returns whether or not
a capability is physical or not, and uses that in sameRegionAs
