On Mon, Oct 16, 2017 at 09:05:22AM -0700, David Daney wrote: > 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@xxxxxxxxxx> > > > > 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. Thanks for the explanation. I've applied this patch pending any further progress in this area.
