svn commit: r258359 - head/sys/arm/arm

[Zbigniew Bodek]

Author: zbb
Date: Tue Nov 19 23:37:50 2013
New Revision: 258359
URL: http://svnweb.freebsd.org/changeset/base/258359

Log:
  Apply access flags for managed and unmanaged pages properly on ARMv6/v7
  
  When entering a mapping via pmap_enter() unmanaged pages ought to be
  naturally excluded from the "modified" and "referenced" emulation.
  RW permission should be granted implicitly when requested,
  otherwise unmanaged page will not recover from the permission fault
  since there will be no PV entry to indicate that the page can be written.
  
  In addition, only managed pages that participate in "modified"
  emulation need to be marked as "dirty" and "writeable" when entered
  with RW permissions. Likewise with "referenced" flag for managed pages.
  Unmanaged ones however should not be marked as such.
  
  Reviewed by:	cognet, gber

Modified:
  head/sys/arm/arm/pmap-v6.c

Modified: head/sys/arm/arm/pmap-v6.c
==============================================================================
--- head/sys/arm/arm/pmap-v6.c	Tue Nov 19 23:31:39 2013	(r258358)
+++ head/sys/arm/arm/pmap-v6.c	Tue Nov 19 23:37:50 2013	(r258359)
@@ -3079,36 +3079,38 @@ validate:
 	 * then continue setting mapping parameters
 	 */
 	if (m != NULL) {
-		if (prot & (VM_PROT_ALL)) {
-			if ((m->oflags & VPO_UNMANAGED) == 0)
+		if ((m->oflags & VPO_UNMANAGED) == 0) {
+			if (prot & (VM_PROT_ALL)) {
 				vm_page_aflag_set(m, PGA_REFERENCED);
-		} else {
-			/*
-			 * Need to do page referenced emulation.
-			 */
-			npte &= ~L2_S_REF;
+			} else {
+				/*
+				 * Need to do page referenced emulation.
+				 */
+				npte &= ~L2_S_REF;
+			}
 		}
 
 		if (prot & VM_PROT_WRITE) {
-			/*
-			 * Enable write permission if the access type
-			 * indicates write intention. Emulate modified
-			 * bit otherwise.
-			 */
-			if ((access & VM_PROT_WRITE) != 0)
-				npte &= ~(L2_APX);
-
 			if ((m->oflags & VPO_UNMANAGED) == 0) {
-				vm_page_aflag_set(m, PGA_WRITEABLE);
 				/*
-				 * The access type and permissions indicate 
-				 * that the page will be written as soon as
-				 * returned from fault service.
-				 * Mark it dirty from the outset.
+				 * Enable write permission if the access type
+				 * indicates write intention. Emulate modified
+				 * bit otherwise.
 				 */
-				if ((access & VM_PROT_WRITE) != 0)
+				if ((access & VM_PROT_WRITE) != 0) {
+					npte &= ~(L2_APX);
+					vm_page_aflag_set(m, PGA_WRITEABLE);
+					/*
+					 * The access type and permissions
+					 * indicate that the page will be
+					 * written as soon as returned from
+					 * fault service.
+					 * Mark it dirty from the outset.
+					 */
 					vm_page_dirty(m);
-			}
+				}
+			} else
+				npte &= ~(L2_APX);
 		}
 		if (!(prot & VM_PROT_EXECUTE))
 			npte |= L2_XN;