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

From	Eric Anholt <eric@anholt.net>
Newsgroups	linux.kernel
Subject	Re: [PATCH V2] ARM: dts: bcm283x: Reserve first page for firmware
Date	2017-05-09 20:20 +0200
Message-ID	<tFhTP-5nA-19@gated-at.bofh.it> (permalink)
References	<tF9jz-89r-3@gated-at.bofh.it> <tFgEp-4pa-7@gated-at.bofh.it> <tFgEq-4pa-9@gated-at.bofh.it>
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Florian Fainelli <f.fainelli@gmail.com> writes:

> On 05/09/2017 09:48 AM, Eric Anholt wrote:
>> Phil Elwell <phil@raspberrypi.org> 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@raspberrypi.org>
>> 
>> 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.

Thread

[PATCH V2] ARM: dts: bcm283x: Reserve first page for firmware Phil Elwell <phil@raspberrypi.org> - 2017-05-09 11:10 +0200
  Re: [PATCH V2] ARM: dts: bcm283x: Reserve first page for firmware Florian Fainelli <f.fainelli@gmail.com> - 2017-05-09 18:30 +0200
  Re: [PATCH V2] ARM: dts: bcm283x: Reserve first page for firmware Florian Fainelli <f.fainelli@gmail.com> - 2017-05-09 19:00 +0200
    Re: [PATCH V2] ARM: dts: bcm283x: Reserve first page for firmware Eric Anholt <eric@anholt.net> - 2017-05-09 20:20 +0200
  Re: [PATCH V2] ARM: dts: bcm283x: Reserve first page for firmware Eric Anholt <eric@anholt.net> - 2017-05-09 19:00 +0200

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