IO memory read from /proc/vmcore leads to hang.

Daniel Walker danielwa at
Thu Jul 21 13:04:47 PDT 2016

On 07/21/2016 12:33 PM, Maxim Uvarov wrote:
> 2016-07-21 18:19 GMT+03:00 Daniel Walker <danielwa at>:
>>   There appears to be no code which checks what is or is not System ram,
>> there is nothing that checks the device tree to see what is IO memory, and
>> nothing reads /proc/iomem .. So AFAIK nothing cares if it's IO memory, or
>> system ram, and there's no method to config things to skip any memory in the
>> system, except in makedumpfile which can skip symbols not IO memory.
> Daniel,  unfortunately it's long time for me when I looked to powerpc
> code. But I just
> checked that here:
> kexec-tools-2.0.6/kexec/arch/ppc64/kexec-ppc64.c
> is probably what you need.

I have a powerpc32 .. In the powerpc64 file I only see something called 
"reserved-ranges" which may do what I want, however, that doesn't exist 
in the 32bit version.  It appers the reserved-ranges is used by OPAL 
firmware , which I don't have. There doesn't appear to be anything 
generic in ppc64 to exclude device IO memory.


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