Re: kexec failures on ipq4019

[Sricharan R <sricharan-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>]

Hi Andy,

On 6/27/2018 2:47 AM, Andy Strohman wrote:
> On Sun, Jun 17, 2018 at 11:31 PM,  <sricharan-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org> wrote:
>> Hi Andy,
>>
>> On 2018-06-16 06:37, Andy Strohman wrote:
>>>
>>> Hi,
>>>
>>>   I'm trying to get kexec to work consistently for ipq4019.  I load
>>> the crash kernel like this:
>>>
>>> kexec --type zImage -p zImage-initramfs
>>> --dtb=image-qcom-ipq4019-eap1300.dtb --append="maxcpus=1
>>> reset_devices" --image-size=34419456
>>>
>>>   I have reserved 64MB of memory for the crash kernel with parameter:
>>> crashkernel=64M
>>>
>>>   This seems to work ~70% of the time. When it doesn't work, I see the
>>> "bye!" message followed by a 5-10 second hang without output.  Then
>>> the machine resets.
>>>
>>>   I've been testing with:
>>> echo c > /proc/sysrq-trigger
>>>
>>>   Does anyone have an idea of what may be causing the failures or how
>>> to troubleshoot this?
>>>
>>
>>  I will try to reproduce this and get back to you shortly.
>>
>> Regards,
>>  Sricharan
>>
>>
>>>   I'm using OpenWRT with kernel 4.14.37.   I added the following patch
>>> in order to load the crash kernel:
>>>
>>> --- a/arch/arm/mach-qcom/platsmp.c
>>> +++ b/arch/arm/mach-qcom/platsmp.c
>>> @@ -332,6 +332,12 @@ static void __init qcom_smp_prepare_cpus
>>>   }
>>>  }
>>>
>>> +/* Needed by kexec and platform_can_cpu_hotplug() */
>>> +int qcom_cpu_kill(unsigned int cpu)
>>> +{
>>> +    return 1;
>>> +}
>>> +
>>>  static const struct smp_operations smp_msm8660_ops __initconst = {
>>>   .smp_prepare_cpus = qcom_smp_prepare_cpus,
>>>   .smp_secondary_init = qcom_secondary_init,
>>> @@ -358,6 +364,7 @@ static const struct smp_operations qcom_
>>>   .smp_boot_secondary = kpssv2_boot_secondary,
>>>  #ifdef CONFIG_HOTPLUG_CPU
>>>   .cpu_die = qcom_cpu_die,
>>> +    .cpu_kill       = qcom_cpu_kill,
>>>  #endif
>>>  };
>>>  CPU_METHOD_OF_DECLARE(qcom_smp_kpssv2, "qcom,kpss-acc-v2",
>>> &qcom_smp_kpssv2_ops);
>>>
>>>
>>> Thanks,
>>>
>>> Andy
> 
> Hi Sricharan,
> 
>   Thanks for your response.  Did you get a chance to try this out?  If
> so, were you able to reproduce?
> 

   I have been trying to kexec while chroot'ing for a different reason.
   I did not observe a issue so far. But that is with a 4.4.60 openwrt kernel.
   Can you point me a link to the kernel that you are trying with ?

Regards,
 Sricharan

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