RE: [PATCH] ARM: sparsemem: allow pfn_valid to be overridden whenusing SPARSEMEM

From: Will Deacon
Date: Thu May 19 2011 - 05:05:27 EST


On Wed, 2011-05-18 at 19:53 +0100, H Hartley Sweeten wrote:
> On Wednesday, May 18, 2011 9:04 AM, Will Deacon wrote:
> >
> > In commit eb33575c ("[ARM] Double check memmap is actually valid with a
> > memmap has unexpected holes V2"), a new function, memmap_valid_within,
> > was introduced to mmzone.h so that holes in the memmap which pass
> > pfn_valid in SPARSEMEM configurations can be detected and avoided.

[...]

> I tested this on an EP93xx based system which uses ARCH_HAS_HOLES_MEMORYMODEL.
> The EP9307A has 64MB of memory that appears as two 32MB blocks at addresses
> 0xc0000000 and 0xc4000000. Currently the EP93xx uses a Flat Memory model and
> the hole used to cause a Kernel OOPs before commit e80d6a24 ("[ARM] Skip memory
> holes in FLATMEM when reading /proc/pagetypeinfo"), which is where I think this
> all started.
>
[...]

> I'm not sure what the output "should" be, but the patch does not seem to
> cause any issues. So feel free to add:
>
> Tested-by: H Hartley Sweeten <hsweeten@xxxxxxxxxxxxxxxxxxx>

Thanks for that. It's good to know that this patch doesn't break
non-sparsemem platforms with whacky flatmem configurations :)

Will


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