Re: get_pteptr()

David Gibson wrote:

get_pteptr() is used in exactly three places:
	- in arch/ppc/8xx_io/commproc.c in the #else side of a #if 1,
i.e. not really used at all.

That was one of my earliest cache management hacks, that predated iopa()
and consistent_alloc().  You can get rid of it.

	- in do_page_fault() [arch/ppc/mm/fault.c] for the handling of
page execute faults on 40x.  It's use here is arguably incorrect if
large page pmds are introduced, although we won't ever get execute
faults on large pages, so it doesn't really matter.

Hmmmm.....I was always hoping we could use "standard" VM functions to
find and update PTEs, but I guess that isn't happening.  I would suggest
just placing a comment around this about the large pages and leave it.

But given that iopa() is pretty much the only user of this function
(do_page_fault() should be done slightly differently, I think), there
doesn't seem a lot of point.  Why not just eliminate get_pteptr() and
walk the page tables explicitly in iopa().

I sometimes use get_pteptr() for debug.  Make sure xmon doesn't use it
for printing page table information.

[*] Well, apart from removing iopa() entirely, but that's another
flamewar^Wdiscussion.

Just remove it for 4xx, or put an #ifdef in iopa() to do the arithmetic
conversion.  It's only used on 4xx and 8xx, and I would like to ensure
the 8xx still works correctly before we nuke everything.  I would just
be a little careful to ensure you have run enough PCI cards to verify
everything is OK.

Thanks.


	-- Dan


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