[src/trunk]: src/sys/arch/hp300/hp300 Add comments how mm_md_physacc() for hp...

[tsutsui <tsutsui%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/13118294e23c
branches:  trunk
changeset: 985049:13118294e23c
user:      tsutsui <tsutsui%NetBSD.org@localhost>
date:      Fri Aug 06 05:22:21 2021 +0000

description:
Add comments how mm_md_physacc() for hp300 works.

mm_md_physacc() for all other hp300 pmap based m68k ports that copied
hp300 implemantation should have been fixed properly.

XXX: no mm(9) man pages that describe MD implementation API definitions.

diffstat:

 sys/arch/hp300/hp300/machdep.c |  8 ++++++--
 1 files changed, 6 insertions(+), 2 deletions(-)

diffs (29 lines):

diff -r 2be7290780da -r 13118294e23c sys/arch/hp300/hp300/machdep.c
--- a/sys/arch/hp300/hp300/machdep.c    Fri Aug 06 04:21:56 2021 +0000
+++ b/sys/arch/hp300/hp300/machdep.c    Fri Aug 06 05:22:21 2021 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: machdep.c,v 1.234 2020/06/11 19:20:43 ad Exp $ */
+/*     $NetBSD: machdep.c,v 1.235 2021/08/06 05:22:21 tsutsui Exp $    */
 
 /*
  * Copyright (c) 1988 University of Utah.
@@ -39,7 +39,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: machdep.c,v 1.234 2020/06/11 19:20:43 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: machdep.c,v 1.235 2021/08/06 05:22:21 tsutsui Exp $");
 
 #include "opt_ddb.h"
 #include "opt_compat_netbsd.h"
@@ -1164,6 +1164,10 @@
 mm_md_physacc(paddr_t pa, vm_prot_t prot)
 {
 
+       /*
+        * On the hp300, physical RAM is always located at the end of
+        * the physical address space, i.e. from 0xffffffff to lowram.
+        */
        return (pa < lowram || pa >= 0xfffffffc) ? EFAULT : 0;
 }