Re: [PATCH] (2.4.21-bjorn-bk) Minimalist PAL mapping for SN2

From: Bjorn Helgaas <bjorn.helgaas_at_hp.com>
Date: 2003-07-18 03:42:23
On Tuesday 15 July 2003 8:14 pm, Christopher Wedgwood wrote:
> Altix/SN2 presently has the PAL located in a granule that has mixed
> cachability --- for this reason we need to map the PAL using the
> smallest mapping possible.

We had a big discussion inside HP a while back about a similar
issue (firmware reported a region that required run-time mapping
inside a granule that also contained a hole).  We pushed hard to
make everything inside a granule have the same attributes.

Given that you're stuck with this situation:

- I hate to clutter the generic efi.c with so much platform-
  specific stuff.  What are the implications of making this
  a platform vector?  I don't see any obvious dependencies that
  prevent us from doing machvec_init() earlier.

- As Tony mentioned, you might want to verify that there's nothing
  else in the granule that requires run-time mapping.

- If there are different cacheability attributes within a granule,
  efi_memmap_walk should remove the granule from efi_memmap.  Do
  you see that happening?  I guess since PAL is mapped with a TR,
  we probably can live without it being in the EFI memmap, but since
  we use the memmap to validate accesses to /dev/mem, the wrong
  thing will probably happen if you try to read the PAL space.

Bjorn

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Received on Thu Jul 17 13:43:01 2003

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