Re: [RFC/PATCH] arm: do not skip SMP init calls on SMP_ON_UP case

From	Nikita Yushchenko <nyushchenko@dev.rtsoft.ru>
Newsgroups	linux.kernel
Subject	Re: [RFC/PATCH] arm: do not skip SMP init calls on SMP_ON_UP case
Date	2015-11-23 13:50 +0100
Message-ID	<qxYJc-1N0-7@gated-at.bofh.it> (permalink)
References	<qxXWO-1fN-17@gated-at.bofh.it> <qxY6u-1yt-3@gated-at.bofh.it> <qxY6t-1yt-1@gated-at.bofh.it> <qxYzw-1JL-9@gated-at.bofh.it>
Organization	RTSoft Software Development Center

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>>>> 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@0  cpu@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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Thread

[RFC/PATCH] arm: do not skip SMP init calls on SMP_ON_UP case nyushchenko@dev.rtsoft.ru - 2015-11-23 13:00 +0100
  Re: [RFC/PATCH] arm: do not skip SMP init calls on SMP_ON_UP case Nikita Yushchenko <nyushchenko@dev.rtsoft.ru> - 2015-11-23 13:10 +0100
    Re: [RFC/PATCH] arm: do not skip SMP init calls on SMP_ON_UP case Russell King - ARM Linux <linux@arm.linux.org.uk> - 2015-11-23 13:20 +0100
      Re: [RFC/PATCH] arm: do not skip SMP init calls on SMP_ON_UP case Nikita Yushchenko <nyushchenko@dev.rtsoft.ru> - 2015-11-23 13:50 +0100
    Re: [RFC/PATCH] arm: do not skip SMP init calls on SMP_ON_UP case Russell King - ARM Linux <linux@arm.linux.org.uk> - 2015-11-23 13:20 +0100
    Re: [RFC/PATCH] arm: do not skip SMP init calls on SMP_ON_UP case Vladimir Murzin <vladimir.murzin@arm.com> - 2015-11-23 13:40 +0100
      Re: [RFC/PATCH] arm: do not skip SMP init calls on SMP_ON_UP case Nikita Yushchenko <nyushchenko@dev.rtsoft.ru> - 2015-11-23 13:50 +0100
        Re: [RFC/PATCH] arm: do not skip SMP init calls on SMP_ON_UP case Russell King - ARM Linux <linux@arm.linux.org.uk> - 2015-11-23 14:10 +0100
          Re: [RFC/PATCH] arm: do not skip SMP init calls on SMP_ON_UP case Nikita Yushchenko <nyushchenko@dev.rtsoft.ru> - 2015-11-24 16:00 +0100
            Re: [RFC/PATCH] arm: do not skip SMP init calls on SMP_ON_UP case Nikita Yushchenko <nyushchenko@dev.rtsoft.ru> - 2015-11-24 16:10 +0100
              Re: [RFC/PATCH] arm: do not skip SMP init calls on SMP_ON_UP case Nikita Yushchenko <nyushchenko@dev.rtsoft.ru> - 2015-11-24 16:30 +0100
            Re: [RFC/PATCH] arm: do not skip SMP init calls on SMP_ON_UP case Russell King - ARM Linux <linux@arm.linux.org.uk> - 2015-11-24 16:40 +0100
              Re: [RFC/PATCH] arm: do not skip SMP init calls on SMP_ON_UP case Nikita Yushchenko <nyushchenko@dev.rtsoft.ru> - 2015-11-28 12:20 +0100
                Re: [RFC/PATCH] arm: do not skip SMP init calls on SMP_ON_UP case Nikita Yushchenko <nyushchenko@dev.rtsoft.ru> - 2015-11-30 09:30 +0100
      Re: [RFC/PATCH] arm: do not skip SMP init calls on SMP_ON_UP case Nikita Yushchenko <nyushchenko@dev.rtsoft.ru> - 2015-11-23 13:50 +0100
  Re: [RFC/PATCH] arm: do not skip SMP init calls on SMP_ON_UP case Russell King - ARM Linux <linux@arm.linux.org.uk> - 2015-11-23 13:10 +0100

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