[src/trunk]: src/sys/arch/amd64/amd64 Kill dependency to xpmap_update(), and ...

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

details:   https://anonhg.NetBSD.org/src/rev/28437c2b0107
branches:  trunk
changeset: 771488:28437c2b0107
user:      jym <jym%NetBSD.org@localhost>
date:      Wed Nov 23 01:15:02 2011 +0000

description:
Kill dependency to xpmap_update(), and use setbits/clearbits to update
kernel PTE rights.

diffstat:

 sys/arch/amd64/amd64/db_memrw.c |  39 ++++++++++++++++-----------------------
 1 files changed, 16 insertions(+), 23 deletions(-)

diffs (97 lines):

diff -r 688d1123f117 -r 28437c2b0107 sys/arch/amd64/amd64/db_memrw.c
--- a/sys/arch/amd64/amd64/db_memrw.c   Wed Nov 23 01:07:50 2011 +0000
+++ b/sys/arch/amd64/amd64/db_memrw.c   Wed Nov 23 01:15:02 2011 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: db_memrw.c,v 1.8 2010/12/20 00:25:24 matt Exp $        */
+/*     $NetBSD: db_memrw.c,v 1.9 2011/11/23 01:15:02 jym Exp $ */
 
 /*-
  * Copyright (c) 1996, 2000 The NetBSD Foundation, Inc.
@@ -51,9 +51,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: db_memrw.c,v 1.8 2010/12/20 00:25:24 matt Exp $");
-
-#include "opt_xen.h"
+__KERNEL_RCSID(0, "$NetBSD: db_memrw.c,v 1.9 2011/11/23 01:15:02 jym Exp $");
 
 #include <sys/param.h>
 #include <sys/proc.h>
@@ -99,7 +97,7 @@
 static void
 db_write_text(vaddr_t addr, size_t size, const char *data)
 {
-       pt_entry_t *pte, oldpte, tmppte;
+       pt_entry_t *ppte, pte;
        vaddr_t pgva;
        size_t limit;
        char *dst;
@@ -113,10 +111,10 @@
                /*
                 * Get the PTE for the page.
                 */
-               pte = kvtopte(addr);
-               oldpte = *pte;
+               ppte = kvtopte(addr);
+               pte = *ppte;
 
-               if ((oldpte & PG_V) == 0) {
+               if ((pte & PG_V) == 0) {
                        printf(" address %p not a valid page\n", dst);
                        return;
                }
@@ -124,7 +122,7 @@
                /*
                 * Get the VA for the page.
                 */
-               if (oldpte & PG_PS)
+               if (pte & PG_PS)
                        pgva = (vaddr_t)dst & PG_LGFRAME;
                else
                        pgva = x86_trunc_page(dst);
@@ -134,7 +132,7 @@
                 * with this mapping and subtract it from the
                 * total size.
                 */
-               if (oldpte & PG_PS)
+               if (pte & PG_PS)
                        limit = NBPD_L2 - ((vaddr_t)dst & (NBPD_L2 - 1));
                else
                        limit = PAGE_SIZE - ((vaddr_t)dst & PGOFSET);
@@ -142,12 +140,11 @@
                        limit = size;
                size -= limit;
 
-               tmppte = (oldpte & ~PG_KR) | PG_KW;
-#ifdef XEN
-               xpmap_update(pte, tmppte);
-#else
-               *pte = tmppte;
-#endif
+               /*
+                * Make the kernel text page writable.
+                */
+               pmap_pte_clearbits(ppte, PG_KR);
+               pmap_pte_setbits(ppte, PG_KW);
                pmap_update_pg(pgva);
 
                /*
@@ -158,14 +155,10 @@
                        *dst++ = *data++;
 
                /*
-                * Restore the old PTE.
+                * Turn the page back to read-only.
                 */
-#ifdef XEN
-               xpmap_update(pte, oldpte);
-#else
-               *pte = oldpte;
-#endif
-
+               pmap_pte_clearbits(ppte, PG_KW);
+               pmap_pte_setbits(ppte, PG_KR);
                pmap_update_pg(pgva);
                
        } while (size != 0);