[PATCH 3/4] kexec-tools: mips: Use proper page_offset for OCTEON CPUs.

[David Daney]

On 10/15/2017 11:56 PM, Simon Horman wrote:
> On Thu, Oct 12, 2017 at 02:02:27PM -0700, David Daney wrote:
>> The OCTEON family of MIPS64 CPUs uses a PAGE_OFFSET of
>> 0x8000000000000000ULL, which is differs from other CPUs.
>>
>> Scan /proc/cpuinfo to see if the current system is "Octeon", if so,
>> patch the page_offset so that usable kdump core files are produced.
>>
>> Signed-off-by: David Daney <david.daney at cavium.com>
> 
> Is it possible to read this offset from the system rather than
> checking for an Octeon CPU? It seems that such an approach, if possible,
> would be somewhat more general.
> 

Before implementing this scanning of /proc/cpuinfo, I thought long and 
hard about this, and couldn't think of how the PAGE_OFFSET could be 
derived from information available in userspace.

Ralf (MIPS maintainer) may have an idea, but these address bits don't 
show up in /proc/kallsyms or any other file in /proc or /sys that I am 
aware of.

David