Re: [RFC/PATCH] powerpc: rework 4xx PTE access and TLB miss

On Wed, 11 Jun 2008 10:50:31 +1000
Benjamin Herrenschmidt [off-list ref] wrote:

This is some preliminary work to improve TLB management on SW loaded
TLB powerpc platforms. This introduce support for non-atomic PTE
operations in pgtable-ppc32.h and removes write back to the PTE from
the TLB miss handlers. In addition, the DSI interrupt code no longer
tries to fixup write permission, this is left to generic code, and
_PAGE_HWWRITE is gone.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---

This is a first step, plan is to do the same for FSL BookE, 405 and
possibly 8xx too. From there, I want to rework a bit the execute
permission handling to avoid multiple faults, add support for
_PAGE_EXEC (no executable mappings), for prefaulting (especially
for kmap) and proper SMP support for future SMP capable BookE
platforms.

I've looked this over quite a bit and can't find anything wrong with
it.  As soon as I get my boards set back up next week, I will try it
out on a few and see if I can find a good stress test as well.

If you could add the comments that Kumar suggested and send out an
updated patch, I'm inclined to get this into 2.6.27, but we should do
that soon if that is our target.

josh