Messages in this thread | | | From | Rob Herring <> | Date | Thu, 7 Aug 2014 10:22:28 -0500 | Subject | Re: [PATCH 1/7] arm: use generic fixmap.h |
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On Thu, Aug 7, 2014 at 10:15 AM, Max Filippov <jcmvbkbc@gmail.com> wrote: > Hi, > > On Wed, Aug 6, 2014 at 11:32 PM, Kees Cook <keescook@chromium.org> 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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