CVS commit: src

["Michael L. Hitch" <mhitch%netbsd.org@localhost>]

Module Name:    src
Committed By:   mhitch
Date:           Fri Mar  5 22:25:08 UTC 1999

Modified Files:
        src/sys/arch/mips/mips: pmap.c
Log Message:
Read-only unnmanaged pages on MIPS3 need the RO attribute bit, otherwise the
tlbmod exception panics.  This appears to have been incorrect even in the pica
pmap.c, which I pulled in for the pmax.  Fixes Xcfbpmax crashes on R40x0
systems with sfb framebuffer.

Fix resident_count tracking so it doesn't go negative.  UVM will change a
page mapping without removing the original mapping.  That was causing a
problem early on when getting UVM working on the mips, and the explicit
pmap_remove() done by pmap_enter() was decrementing the resident_count.
Do the pmap_remove() first, then check if the current mapping is not valid
and increment the resident_count.