All SH-X2 and SH-X3 parts support an extended TLB mode, which has been
left as experimental since support was originally merged. Now that it's
had some time to stabilize and get some exposure to various platforms,
we can drop it as an option and default enable it across the board.
This is also good future proofing for newer parts that will drop support
for the legacy TLB mode completely.
This will also force 3-level page tables for all newer parts, which is
necessary both for the varying page sizes and larger memories.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
The previous expressions were wrong which made free_pmd_range() explode
when using anything other than 4KB pages (which is why 8KB and 64KB
pages were disabled with the 3-level page table layout).
The problem was that pmd_offset() was returning an index of non-zero
when it should have been returning 0. This non-zero offset was used to
calculate the address of the pmd table to free in free_pmd_range(),
which ended up trying to free an object that was not aligned on a page
boundary.
Now 3-level page tables should work with 4KB, 8KB and 64KB pages.
Signed-off-by: Matt Fleming <matt@console-pimps.org>
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 <matt@console-pimps.org>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
