Re: [PATCH 3/7] mtrr: Remove use_intel()

From: Michał Mirosław
Date: Wed Dec 09 2009 - 03:44:20 EST


On Wed, Dec 09, 2009 at 12:10:50AM -0800, Yinghai Lu wrote:
> 2009/12/8 Michał Mirosław <mirq-linux@xxxxxxxxxxxx>:
> > Remove use_intel() and use is_cpu(INTEL) instead.
> >
> > .use_intel_if is duplicating information already found in .vendor, as
> > the only combinations used are:
> >    generic: use_intel_if == 1, vendor == INTEL
> >    amd/cyrix/centaur: use_intel_if == 0, vendor != INTEL
> >
[...]
> can you check it with amd64 cpu?

Unfortunately I don't have any AMD machines right now.

Anyway, just to clarify why the change is a functional no-op: use_intel()
and is_cpu(X) don't check the detected CPU vendor ID but look into mtrr_ops
struct. For 64BIT build this means that use_intel() / is_cpu(INTEL) == true
when mtrr_if != NULL, and all other is_cpu() == false because no other
implementation could be choosen (amd/cyrix/centaur special cpu features are
possible only in 32BIT).

Best Regards,
Michał Mirosław
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