The following diagrams are my attempt to show how the page tables are arranged on various architectures. Each diagram shows the layout for the base page size as well as the hugetlb page size.
i386 with PAE enabled
attachment:i%33%38%36%2Bpae.png
powerpc with 4k base pages
attachment:powerpc-4k.png
powerpc with 64k base pages
attachment:powerpc-64k.png