K 10
svn:author
V 3
alc
K 8
svn:date
V 27
2019-07-09T20:28:53.836446Z
K 7
svn:log
V 955
Introduce pmap_clear(), which zeroes a page table entry, and use it, instead
of pmap_load_clear(), in places where we don't care about the page table
entry's prior contents.

Eliminate an unnecessary pmap_load() from pmap_remove_all().  Instead, use
the value returned by the pmap_load_clear() on the very next line.  (In the
future, when we support "hardware dirty bit management", using the value
from the pmap_load() rather than the pmap_load_clear() would have actually
been an error because the dirty bit could potentially change between the
pmap_load() and the pmap_load_clear().)

A KASSERT() in pmap_enter(), which originated in the amd64 pmap, was meant
to check the value returned by the pmap_load_clear() on the previous line.
However, we were ignoring the value returned by the pmap_load_clear(), and
so the KASSERT() was not serving its intended purpose.  Use the value
returned by the pmap_load_clear() in the KASSERT().

MFC after:	2 weeks

END