Re: [PATCH 1/7] arm: use generic fixmap.h

[Rob Herring]

On Thu, Aug 7, 2014 at 10:15 AM, Max Filippov <jcmvbkbc@xxxxxxxxx> wrote:
> Hi,
>
> On Wed, Aug 6, 2014 at 11:32 PM, Kees Cook <keescook@xxxxxxxxxxxx> wrote:
>> ARM is different from other architectures in that fixmap pages are indexed
>> with a positive offset from FIXADDR_START.  Other architectures index with
>> a negative offset from FIXADDR_TOP.  In order to use the generic fixmap.h
>
> Does anybody know if there's any reason why generic fixmap.h uses negative
> offsets? It complicates things with no obvious benefit if you e.g. try to align
> virtual address in the fixmap region with physical page color (that's why I've
> switched xtensa to positive fixmap addressing in v3.17).

No, but each arch doing it differently is even more annoying.

Rob
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