[src/trunk]: src/sys/arch/sun3/sun3x Renamed a temporary variable in pmap_ent...

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

details:   https://anonhg.NetBSD.org/src/rev/9214289d2ce7
branches:  trunk
changeset: 479659:9214289d2ce7
user:      jeremy <jeremy%NetBSD.org@localhost>
date:      Fri Dec 17 08:10:59 1999 +0000

description:
Renamed a temporary variable in pmap_enter() that conflicted with the
name of the new 'flags' argument, added as part of the new pmap_enter() API.
Added a comment which explains why there are still sun3x-specific flags
being passed in the unused bits of the physical address, and how these flags
are independent of the new 'flags' argument.

diffstat:

 sys/arch/sun3/sun3x/pmap.c |  37 ++++++++++++++++++++++++++++++-------
 1 files changed, 30 insertions(+), 7 deletions(-)

diffs (79 lines):

diff -r 890474f89b53 -r 9214289d2ce7 sys/arch/sun3/sun3x/pmap.c
--- a/sys/arch/sun3/sun3x/pmap.c        Fri Dec 17 07:40:09 1999 +0000
+++ b/sys/arch/sun3/sun3x/pmap.c        Fri Dec 17 08:10:59 1999 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: pmap.c,v 1.51 1999/11/13 00:32:19 thorpej Exp $        */
+/*     $NetBSD: pmap.c,v 1.52 1999/12/17 08:10:59 jeremy Exp $ */
 
 /*-
  * Copyright (c) 1996, 1997 The NetBSD Foundation, Inc.
@@ -1682,7 +1682,7 @@
        boolean_t insert, managed; /* Marks the need for PV insertion.*/
        u_short nidx;            /* PV list index                     */
        int s;                   /* Used for splimp()/splx()          */
-       int flags;               /* Mapping flags. eg. Cache inhibit  */
+       int mapflags;            /* Flags for the mapping (see NOTE1) */
        u_int a_idx, b_idx, pte_idx; /* table indices                 */
        a_tmgr_t *a_tbl;         /* A: long descriptor table manager  */
        b_tmgr_t *b_tbl;         /* B: short descriptor table manager */
@@ -1691,7 +1691,7 @@
        mmu_short_dte_t *b_dte;  /* B: short descriptor table         */
        mmu_short_pte_t *c_pte;  /* C: short page descriptor table    */
        pv_t      *pv;           /* pv list head                      */
-       boolean_t wired = (flags & PMAP_WIRED) != 0;
+       boolean_t wired;         /* is the mapping to be wired?       */
        enum {NONE, NEWA, NEWB, NEWC} llevel; /* used at end   */
 
        if (pmap == NULL)
@@ -1701,8 +1701,31 @@
                return (KERN_SUCCESS);
        }
 
-       flags  = (pa & ~MMU_PAGE_MASK);
-       pa    &= MMU_PAGE_MASK;
+       /*
+        * Determine if the mapping should be wired.
+        */
+       wired = ((flags & PMAP_WIRED) != 0);
+
+       /*
+        * NOTE1:
+        *
+        * On November 13, 1999, someone changed the pmap_enter() API such
+        * that it now accepts a 'flags' argument.  This new argument
+        * contains bit-flags for the architecture-independent (UVM) system to
+        * use in signalling certain mapping requirements to the architecture-
+        * dependent (pmap) system.  The argument it replaces, 'wired', is now
+        * one of the flags within it.
+        *
+        * In addition to flags signaled by the architecture-independent
+        * system, parts of the architecture-dependent section of the sun3x
+        * kernel pass their own flags in the lower, unused bits of the
+        * physical address supplied to this function.  These flags are
+        * extracted and stored in the temporary variable 'mapflags'.
+        *
+        * Extract sun3x specific flags from the physical address.
+        */ 
+       mapflags  = (pa & ~MMU_PAGE_MASK);
+       pa       &= MMU_PAGE_MASK;
 
        /*
         * Determine if the physical address being mapped is on-board RAM.
@@ -1710,7 +1733,7 @@
         * device and hence it would be disasterous to cache its contents.
         */
        if ((managed = is_managed(pa)) == FALSE)
-               flags |= PMAP_NC;
+               mapflags |= PMAP_NC;
 
        /*
         * For user mappings we walk along the MMU tables of the given
@@ -2000,7 +2023,7 @@
         * bits found on the lower order of the physical address.)
         * mark the PTE as a cache inhibited page.
         */
-       if (flags & PMAP_NC)
+       if (mapflags & PMAP_NC)
                c_pte->attr.raw |= MMU_SHORT_PTE_CI;
 
        /*