3.3.12. Subpages

You can define access permissions for subpages of small and large pages. If, during a page walk, a small or large page has a non-identical subpage permission, only the subpage being accessed is written into the TLB. For example, a 16KB (large page) subpage entry is written into the TLB if the subpage permission differs, and a 64KB entry is put in the TLB if the subpage permissions are identical.

When you use subpage permissions, and the page entry then has to be invalidated, you must invalidate all four subpages separately.

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