[PATCH] [v2] powerpc/4xx: work around CHIP11 errata in a more PAGE_SIZE-friendly way

David Gibson dwg at au1.ibm.com
Wed Nov 12 10:20:06 EST 2008


On Tue, Nov 11, 2008 at 07:52:18AM -0500, Josh Boyer wrote:
> On Mon, Nov 10, 2008 at 05:24:34PM -0600, Hollis Blanchard wrote:
> >The current CHIP11 errata truncates the device tree memory node, and subtracts
> >(hardcoded) 4096 bytes. This breaks kernels with larger PAGE_SIZE, since the
> >bootmem allocator assumes that total memory is a multiple of PAGE_SIZE.
> >
> >Instead, use a device tree memory reservation to reserve only the 256 bytes
> >actually affected by the errata, leaving the total memory size unaltered.
> >
> >Signed-off-by: Hollis Blanchard <hollisb at us.ibm.com>
> >
> >---
> >
> >Using large pages results in a huge performance improvement for KVM, and this
> >patch is required to make Ilya's large page patch work. David and/or Josh,
> >please apply.
> 
> The patch looks fine to me, and once David acks the fdt parts I'll apply
> for -next.  I'll try to do some testing later today as well, since I have
> one of the boards with the Errata.

Um.. I sent something the fdt stuff a while back, but didn't get a
response.

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson



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