Re: [PATCH V2] ARM: dts: bcm283x: Reserve first page for firmware

From: Eric Anholt
Date: Tue May 09 2017 - 14:11:06 EST


Florian Fainelli <f.fainelli@xxxxxxxxx> writes:

> On 05/09/2017 09:48 AM, Eric Anholt wrote:
>> Phil Elwell <phil@xxxxxxxxxxxxxxx> writes:
>>
>>> The Raspberry Pi startup stub files for multi-core BCM27XX processors
>>> make the secondary CPUs spin until the corresponding mailbox is
>>> written. These stubs are loaded at physical address 0x00000xxx (as seen
>>> by the ARMs), but this page will be reused by the kernel unless it is
>>> explicitly reserved, causing the waiting cores to execute random code.
>>>
>>> Use the /memreserve/ Device Tree directive to mark the first page as
>>> off-limits to the kernel.
>>>
>>> See: https://github.com/raspberrypi/linux/issues/1989
>>>
>>> Signed-off-by: Phil Elwell <phil@xxxxxxxxxxxxxxx>
>>
>> This looks great. We're currently in the merge window, so I can't
>> generate a new bcm2835-dt-next yet, but I'll pick this patch up when I
>> do.
>>
>> Thanks for submitting upstream!
>
> Considering that this is a fix, we could actually squeeze it in the
> devicetree/fixes branch and we could submit those as soon as v4.12-rc1
> is tagged, your call.

While the issue is a bit obscure, I know I've hit it as well. I agree
that it's a good stable candidate, so unless you'd like to pick it
yourself and cc stable, I'll just send you a PR doing so when rc1 rolls
around.

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