Move the page table traversal and splitting logic to a separate function UpdateRegionMapping() and refactor it slightly so we can reuse it later to implement non-executable regions, for the stack. This primarly involves adding a value/mask pair to the function prototype that allows us to flip arbitrary bits on each block entry as the page tables are traversed. Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org> git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@18586 6f19259b-4bc3-4df7-8a09-765794883524