[RFC/PATCH] arm: do not skip SMP init calls on SMP_ON_UP case
Vladimir Murzin
vladimir.murzin at arm.com
Mon Nov 23 04:32:41 PST 2015
On 23/11/15 12:06, Nikita Yushchenko wrote:
> 23.11.2015 15:03, Russell King - ARM Linux пишет:
>> On Mon, Nov 23, 2015 at 02:59:06PM +0300, nyushchenko at dev.rtsoft.ru wrote:
>>> From: Nikita Yushchenko <nyushchenko at dev.rtsoft.ru>
>>>
>>> While running an imx6s boasrd, I got following message in boot log:
>>>
>>> [ 0.032414] CPU1: failed to boot: -38
>>>
>>> This looked strange: imx6s is singe-core and kernel perfectly knows
>>> that. However, for some reason it tries to initialize CPU 1?
>>>
>>> I found this to be caused by
>>> - CONFIG_SMP_ON_UP successfully detects that system is single core,
>>> - this causes is_smp() to return false,
>>> - this causes setup_arch() to skip smp_init_cpus() call,
>>> - this skips board-specific code that sets cpu_possible mask.
>>
>> Right, so you should end up with the possible and present masks
>> containing just one CPU, which should prevent the kernel trying to
>> bring any secondary CPUs online.
>
> Kernel that is running here still tries to init CPU 1 for some reason.
I *guess* cpus node [1] in your dts has more than one cpu entry, could
you check please?
[1] Documentation/devicetree/bindings/arm/cpus.txt
Vladimir
>
> Will try to check mainline (although not sure if that will be possible
> on available custom hardware)
>
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