From: Matt Fleming Date: Sun, 13 Dec 2009 14:38:50 +0000 (+0000) Subject: sh: Definitions for 3-level page table layout X-Git-Tag: v2.6.34-rc1~285^2~154 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5d9b4b19f118abfb75e352841f7bf74580d7e427;p=pandora-kernel.git sh: Definitions for 3-level page table layout If using 64-bit PTEs and 4K pages then each page table has 512 entries (as opposed to 1024 entries with 32-bit PTEs). Unlike MIPS, SH follows the convention that all structures in the page table (pgd_t, pmd_t, pgprot_t, etc) must be the same size. Therefore, 64-bit PTEs require 64-bit PGD entries, etc. Using 2-levels of page tables and 64-bit PTEs it is only possible to map 1GB of virtual address space. In order to map all 4GB of virtual address space we need to adopt a 3-level page table layout. This actually works out better for CONFIG_SUPERH32 because we only waste 2 PGD entries on the P1 and P2 areas (which are untranslated) instead of 256. Signed-off-by: Matt Fleming Signed-off-by: Paul Mundt --- Reading git-diff-tree failed