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 for <linuxppc-dev@lists.ozlabs.org> from <aneesh.kumar@linux.vnet.ibm.com>;
 Sun, 14 Aug 2016 08:25:37 -0600
From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
To: Christophe Leroy <christophe.leroy@c-s.fr>,
 Benjamin Herrenschmidt <benh@kernel.crashing.org>,
 Paul Mackerras <paulus@samba.org>,
 Michael Ellerman <mpe@ellerman.id.au>, Scott Wood <oss@buserror.net>
Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH 6/6] powerpc/8xx: implementation of huge pages
In-Reply-To: <15e0fa7a312245e681cb9ca18ffb875c7820e5fc.1471020647.git.christophe.leroy@c-s.fr>
References: <cover.1471020646.git.christophe.leroy@c-s.fr>
 <15e0fa7a312245e681cb9ca18ffb875c7820e5fc.1471020647.git.christophe.leroy@c-s.fr>
Date: Sun, 14 Aug 2016 19:55:30 +0530
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Christophe Leroy <christophe.leroy@c-s.fr> writes:

> The 8xx has 512k and 8M pages. This patch implements hugepages using
> those sizes.
>
> On the 8xx, the size of pages is in the PGD entry,
> using PS field (bits 28-29):
> 00 : Small pages (4k or 16k)
> 01 : 512k pages
> 10 : reserved
> 11 : 8M pages
>
> The implementation uses a mix of what is used on BOOKS and BOOKE,
> as 512k pages are in HUGEPTE tables while for 8M pages we have
> several PGD entries pointing on a leaf HUGEPTE entry
>
> For the time being, we do not support CPU15 ERRATA if HUGETLB is
> selected

Can you also document here the format for linux page table with different
huge page size. ?

>
> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>