svn commit: r342686 - in head/sys: amd64/amd64 i386/i386

[Mark Johnston]

Author: markj
Date: Wed Jan  2 15:36:35 2019
New Revision: 342686
URL: https://svnweb.freebsd.org/changeset/base/342686

Log:
  Avoid setting PG_U unconditionally in pmap_enter_quick_locked().
  
  This KPI may in principle be used to create kernel mappings, in which
  case we certainly should not be setting PG_U.  In any case, PG_U must be
  set on all layers in the page tables to grant user mode access, and we
  were only setting it on leaf entries.  Thus, this change should have no
  functional impact.
  
  Reviewed by:	kib
  MFC after:	1 week
  Sponsored by:	The FreeBSD Foundation

Modified:
  head/sys/amd64/amd64/pmap.c
  head/sys/i386/i386/pmap.c

Modified: head/sys/amd64/amd64/pmap.c
==============================================================================
--- head/sys/amd64/amd64/pmap.c	Wed Jan  2 15:13:08 2019	(r342685)
+++ head/sys/amd64/amd64/pmap.c	Wed Jan  2 15:36:35 2019	(r342686)
@@ -5453,8 +5453,7 @@ pmap_enter_quick_locked(pmap_t pmap, vm_offset_t va, v
     vm_prot_t prot, vm_page_t mpte, struct rwlock **lockp)
 {
 	struct spglist free;
-	pt_entry_t *pte, PG_V;
-	vm_paddr_t pa;
+	pt_entry_t newpte, *pte, PG_V;
 
 	KASSERT(va < kmi.clean_sva || va >= kmi.clean_eva ||
 	    (m->oflags & VPO_UNMANAGED) != 0,
@@ -5544,17 +5543,15 @@ pmap_enter_quick_locked(pmap_t pmap, vm_offset_t va, v
 	 */
 	pmap_resident_count_inc(pmap, 1);
 
-	pa = VM_PAGE_TO_PHYS(m) | pmap_cache_bits(pmap, m->md.pat_mode, 0);
+	newpte = VM_PAGE_TO_PHYS(m) | PG_V |
+	    pmap_cache_bits(pmap, m->md.pat_mode, 0);
+	if ((m->oflags & VPO_UNMANAGED) == 0)
+		newpte |= PG_MANAGED;
 	if ((prot & VM_PROT_EXECUTE) == 0)
-		pa |= pg_nx;
-
-	/*
-	 * Now validate mapping with RO protection
-	 */
-	if ((m->oflags & VPO_UNMANAGED) != 0)
-		pte_store(pte, pa | PG_V | PG_U);
-	else
-		pte_store(pte, pa | PG_V | PG_U | PG_MANAGED);
+		newpte |= pg_nx;
+	if (va < VM_MAXUSER_ADDRESS)
+		newpte |= PG_U;
+	pte_store(pte, newpte);
 	return (mpte);
 }
 

Modified: head/sys/i386/i386/pmap.c
==============================================================================
--- head/sys/i386/i386/pmap.c	Wed Jan  2 15:13:08 2019	(r342685)
+++ head/sys/i386/i386/pmap.c	Wed Jan  2 15:36:35 2019	(r342686)
@@ -4095,8 +4095,7 @@ static vm_page_t
 pmap_enter_quick_locked(pmap_t pmap, vm_offset_t va, vm_page_t m,
     vm_prot_t prot, vm_page_t mpte)
 {
-	pt_entry_t *pte;
-	vm_paddr_t pa;
+	pt_entry_t newpte, *pte;
 	struct spglist free;
 
 	KASSERT(pmap != kernel_pmap || va < kmi.clean_sva ||
@@ -4179,19 +4178,17 @@ pmap_enter_quick_locked(pmap_t pmap, vm_offset_t va, v
 	 */
 	pmap->pm_stats.resident_count++;
 
-	pa = VM_PAGE_TO_PHYS(m) | pmap_cache_bits(pmap, m->md.pat_mode, 0);
+	newpte = VM_PAGE_TO_PHYS(m) | PG_V |
+	    pmap_cache_bits(pmap, m->md.pat_mode, 0);
+	if ((m->oflags & VPO_UNMANAGED) == 0)
+		newpte |= PG_MANAGED;
 #if defined(PAE) || defined(PAE_TABLES)
 	if ((prot & VM_PROT_EXECUTE) == 0)
-		pa |= pg_nx;
+		newpte |= pg_nx;
 #endif
-
-	/*
-	 * Now validate mapping with RO protection
-	 */
-	if ((m->oflags & VPO_UNMANAGED) != 0)
-		pte_store(pte, pa | PG_V | PG_U);
-	else
-		pte_store(pte, pa | PG_V | PG_U | PG_MANAGED);
+	if (pmap != kernel_pmap)
+		newpte |= PG_U;
+	pte_store(pte, newpte);
 	sched_unpin();
 	return (mpte);
 }