mmaping a fixed address fails on ARM

[Bryan Wu]

On Thu, Jan 13, 2011 at 7:25 PM, Russell King - ARM Linux
<linux at arm.linux.org.uk> wrote:
> On Thu, Jan 13, 2011 at 05:58:01AM +0800, Bryan Wu wrote:
>> The implementation of arch_get_unmapped_area() is different from ARM
>> and x86, that might makes mmap behavior different between ARM and x86.
>> Andre said 2.6.28-versatile. I'm not sure whether it is a regression.
>
> For the same conditions (iow, same mapping) on ARMv7 and ARMv5-only
> kernels vs x86 the results will be the same.  On ARMv6-supporting kernels
> we have aliasing caches to deal with where we intentionally force the
> alignment of non-MAP_FIXED mappings.
>

Right, ARMv6 code is different in arch_get_unmapped_area() code from
others. The different results from x86 is because of some address was
mapped to libraries as Sebastien reported.

Thanks,
-- 
Bryan Wu <bryan.wu at canonical.com>
Kernel Developer    +86.138-1617-6545 Mobile
Ubuntu Kernel Team
Canonical Ltd.      www.canonical.com
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