[RFC/PATCH] arm: do not skip SMP init calls on SMP_ON_UP case
Nikita Yushchenko
nyushchenko at dev.rtsoft.ru
Mon Nov 23 04:42:02 PST 2015
>>>> 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?
Indeed looks so:
# ls /proc/device-tree/cpus
#address-cells #size-cells cpu at 0 cpu at 1 name
But my custom device tree just includes imx6dl.dtsi
So it is imx6dl.dtsi in linux-imx tree broken?..
Still, if I apply change from the patch, issue diappears, since in this
case imx_smp_init_cpus() gets called and initializes possible_cpu mask
properly.
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