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

On Jun 10, 2008, at 7:50 PM, Benjamin Herrenschmidt 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.

You really should add some comment about what you are doing with the  
44x watermark.  As I look at this I'm not clear what that change is  
about and I'm sure in the future someone looking at this will  
wondering why this commit changed those bits.

Otherwise this all looks good (other than my other nit picking comments)

- k