Testing kexec/kdump on ls2085ardb (arm64)

Pratyush Anand panand at redhat.com
Wed Apr 12 12:36:40 EDT 2017

Hi Denys,

On Wednesday 12 April 2017 08:05 PM, Denys Zagorui wrote:
> Hello, Pratyush
> Thanks for your reply.
> Could you describe how i can find out wich enable method used. One more
> things, i made this tests on qemu, and it works. Logs attached.

 From your board log (log_for_com ):

PSCI: PSCI does not exist

and then

[   60.561877] Can't kexec: CPUs are stuck in the kernel.

Above message is coming from machine_kexec_prepare() when 
cpus_are_stuck_in_kernel() returns true. See, its implementation. It 
will return true if number of possible cpus is > 1 and cpu_die() is not 

You can boot your first kernel with nr_cpus=1 in  kernel cmdline and 
then you should be able to kexec to the second kernel from there.

However, it can not be a solution. You should update your firmware with 
psci implementation.

For the time being you can have spin-table work aroudn like this [1], 
but please note that spin-table is discouraged upstream [2].

[2] https://patchwork.kernel.org/patch/7873571/

 From your qemu log:

[    0.000000] psci: probing for conduit method from DT.
[    0.000000] psci: PSCIv0.2 detected in firmware.
[    0.000000] psci: Using standard PSCI v0.2 function IDs
[    0.000000] psci: Trusted OS migration not required

and so it works :-)


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