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-1N0-9@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> <qxYJc-1N0-7@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?..

Just booted mainline...  unline linux-imx, it does not try to init cpu1.

However, imx6dl.dtsi from mainline also has both cpu@0 and cpu@1

So missing piece in linux-imx is elsewhere :(

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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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