svn commit: r197580 - head/sys/amd64/amd64

[Alan Cox]

Author: alc
Date: Mon Sep 28 17:10:27 2009
New Revision: 197580
URL: http://svn.freebsd.org/changeset/base/197580

Log:
  Temporarily disable the use of 1GB page mappings by the direct map.  There
  are currently two problems with the use of 1GB page mappings by the direct
  map.  First, at least one device driver uses pmap_extract() rather than
  DMAP_TO_PHYS() to translate a direct map address to a physical address.
  Unfortunately, neither pmap_extract() nor pmap_kextract() yet support 1GB
  page mappings.  Second, pmap_bootstrap() needs to interrogate the MTRRs to
  ensure that a 1GB page mapping doesn't span two MTRRs of different types.
  
  Reported and tested by: Daniel O'Connor
  MFC after:	3 days

Modified:
  head/sys/amd64/amd64/pmap.c

Modified: head/sys/amd64/amd64/pmap.c
==============================================================================
--- head/sys/amd64/amd64/pmap.c	Mon Sep 28 16:59:47 2009	(r197579)
+++ head/sys/amd64/amd64/pmap.c	Mon Sep 28 17:10:27 2009	(r197580)
@@ -442,7 +442,7 @@ create_pagetables(vm_paddr_t *firstaddr)
 	if (ndmpdp < 4)		/* Minimum 4GB of dirmap */
 		ndmpdp = 4;
 	DMPDPphys = allocpages(firstaddr, NDMPML4E);
-	if ((amd_feature & AMDID_PAGE1GB) == 0)
+	if (TRUE || (amd_feature & AMDID_PAGE1GB) == 0)
 		DMPDphys = allocpages(firstaddr, ndmpdp);
 	dmaplimit = (vm_paddr_t)ndmpdp << PDPSHIFT;
 
@@ -476,7 +476,7 @@ create_pagetables(vm_paddr_t *firstaddr)
 
 	/* Now set up the direct map space using either 2MB or 1GB pages */
 	/* Preset PG_M and PG_A because demotion expects it */
-	if ((amd_feature & AMDID_PAGE1GB) == 0) {
+	if (TRUE || (amd_feature & AMDID_PAGE1GB) == 0) {
 		for (i = 0; i < NPDEPG * ndmpdp; i++) {
 			((pd_entry_t *)DMPDphys)[i] = (vm_paddr_t)i << PDRSHIFT;
 			((pd_entry_t *)DMPDphys)[i] |= PG_RW | PG_V | PG_PS |