powerpc64 memory translations

[Justin Hibbits]

I'm trying to fix a problem with DTrace FBT (it just flat hangs), and
want to use the oldest trick in the book -- writing to a known address
at various points.  Problem I have, though, is that writing to 0x10
virtual, unlike with powerpc32, doesn't write to 0x10 physical.  Is
there any way to get the mapping for the first page of physical memory,
so I can do this debugging?  And to make it always available, so that
I don't have to worry about mapping it when I need to?

Thanks,
Justin