>>> On 13.05.15 at 07:26, <ebiederm at xmission.com> wrote: > The low 640k was weird. We copied it off in purgatory so that it could > be capture in a dump. The linux kernel itself winds up using that > memory fundamentally because to fire up subsequent processors you have > to have memory in the low 640k as processors start in real-mode and > the startup IPI only takes an address in the low 1M. I also remember > things with interrupt descriptor tables. Right, but the point to clarify is whether it is reasonable for the purgatory and/or new kernel to expect the old kernel to set up mappings for special regions like this one. As said before - I don't think this should be done; the old (possibly half broken) kernel shouldn't be forced to do any more than the absolute minimum amount of work to be able to transfer control. Jan
