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Date: Thu, 27 Jun 2013 10:40:24 +0100
From: James Hogan <james.hogan@imgtec.com>
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Subject: Re: [Qemu-devel] [PATCH] hw/mips: align initrd to 64KB to avoid
 kernel error
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To: Peter Maydell <peter.maydell@linaro.org>
Cc: yongbok.kim@imgtec.com, cristian.cuna@imgtec.com, Leon Alrae <leon.alrae@imgtec.com>, qemu-devel@nongnu.org, aurelien@aurel32.net

On 27/06/13 09:12, Peter Maydell wrote:
> On 27 June 2013 08:35, Leon Alrae <leon.alrae@imgtec.com> wrote:
>> From: James Hogan <james.hogan@imgtec.com>
>>
>> The Linux kernel can be configured to use 64KB pages, but it also
>> requires initrd to be page aligned. Therefore, to be safe, align the
>> initrd to 64KB using a new INITRD_PAGE_MASK rather than
>> TARGET_PAGE_MASK.
> 
> This is kind of similar to the ARM bug fixed in 98ed805c3.
> I wonder if we ought to have a per-CPU #define for "largest
> possible page alignment for this architecture" as well as
> "smallest possible" (the latter being TARGET_PAGE_MASK).

Yes, very similar. Although "largest possible" is probably quite Linux
specific so I'm not sure where it should really go (some arches support
pages up to 4MB and beyond, but obviously they're never used as basic
pages by Linux).

LINUX_MAXPAGE_MASK?

> This patch is a reasonable enough way to fix things though,
> so I'm not objecting to it.
> 
> Aside: given the repetitive nature of the context hunks
> observable in this patch, it looks like it ought to be
> possible to abstract out some of the initrd/kernel load
> code from all those boards...

That thought did occur to me too :)

Cheers
James