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SubjectRe: [PATCH] Add VDSO time function support for x86 32-bit kernel
On 12/13/2012 11:32 AM, Andy Lutomirski wrote:
>
> x32's vdso cheats -- x32 code can see high addresses just fine. The
> toolchain just makes it difficult.
>
> Your best bet is probably to just map the vvar page twice -- once at
> the same address as native 32-bit mode (but only for compat tasks)
> would use and once in the usual fixmap location. You can't use the
> fixmap for the compat mapping, though, since it would be a *user*
> address.
>
> For HPET support, you'd have to have special support. I'd say to skip
> it for compat mode.
>

Whatever data you need you can just map it into the vdso range. There
really shouldn't be anything special about that at all.

The fixmap stuff is an x86-64 legacy that you don't have to worry about,
obviously.

-hpa

--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.



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