Re: [RFC/PATCH] arm: do not skip SMP init calls on SMP_ON_UP case
From: Nikita Yushchenko
Date: Mon Nov 23 2015 - 07:06:58 EST
23.11.2015 15:03, Russell King - ARM Linux ÐÐÑÐÑ:
> On Mon, Nov 23, 2015 at 02:59:06PM +0300, nyushchenko@xxxxxxxxxxxxx wrote:
>> From: Nikita Yushchenko <nyushchenko@xxxxxxxxxxxxx>
>> 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.
Will try to check mainline (although not sure if that will be possible
on available custom hardware)
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