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
