llext: Support memory protection

Sets up memory partitions and allows for the partitions to be added to a
memory domain after loading an extension. This allows for applying
memory protection attributes to all of the needed memory regions an
extension requires to execute code correctly.

Currently only works when usermode is enabled as otherwise memory
protection APIs are unavailable.

Signed-off-by: Tom Burdick <thomas.burdick@intel.com>
5 files changed