Konstantin Belousov 91a82f9585 Callers of pmap_kextract() cannot distinguish between failure and
physical address zero.  Assume that the lowest page is always mapped
by direct map.

This restores access to the page at zero through /dev/mem after
r263475.

Reported and tested by:	neel
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
2015-01-02 01:05:08 +00:00
..
2014-07-23 15:53:29 +00:00
2015-01-01 18:43:31 +00:00