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Date:      Sat, 4 Jan 2020 19:50:25 +0000 (UTC)
From:      Alan Cox <alc@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r356354 - in head/sys: amd64/amd64 arm64/arm64 i386/i386
Message-ID:  <202001041950.004JoPY6044815@repo.freebsd.org>
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Author: alc
Date: Sat Jan  4 19:50:25 2020
New Revision: 356354
URL: https://svnweb.freebsd.org/changeset/base/356354

Log:
  When a copy-on-write fault occurs, pmap_enter() is called on to replace the
  mapping to the old read-only page with a mapping to the new read-write page.
  To destroy the old mapping, pmap_enter() must destroy its page table and PV
  entries and invalidate its TLB entry.  This change simply invalidates that
  TLB entry a little earlier, specifically, on amd64 and arm64, before the PV
  list lock is held.
  
  Reviewed by:	kib, markj
  MFC after:	1 week
  Differential Revision:	https://reviews.freebsd.org/D23027

Modified:
  head/sys/amd64/amd64/pmap.c
  head/sys/arm64/arm64/pmap.c
  head/sys/i386/i386/pmap.c

Modified: head/sys/amd64/amd64/pmap.c
==============================================================================
--- head/sys/amd64/amd64/pmap.c	Sat Jan  4 19:29:25 2020	(r356353)
+++ head/sys/amd64/amd64/pmap.c	Sat Jan  4 19:50:25 2020	(r356354)
@@ -6131,8 +6131,10 @@ retry:
 			 */
 			if ((origpte & (PG_M | PG_RW)) == (PG_M | PG_RW))
 				vm_page_dirty(om);
-			if ((origpte & PG_A) != 0)
+			if ((origpte & PG_A) != 0) {
+				pmap_invalidate_page(pmap, va);
 				vm_page_aflag_set(om, PGA_REFERENCED);
+			}
 			CHANGE_PV_LIST_LOCK_TO_PHYS(&lock, opa);
 			pv = pmap_pvh_remove(&om->md, pmap, va);
 			KASSERT(pv != NULL,
@@ -6144,9 +6146,13 @@ retry:
 			    ((om->flags & PG_FICTITIOUS) != 0 ||
 			    TAILQ_EMPTY(&pa_to_pvh(opa)->pv_list)))
 				vm_page_aflag_clear(om, PGA_WRITEABLE);
-		}
-		if ((origpte & PG_A) != 0)
+		} else {
+			/*
+			 * Since this mapping is unmanaged, assume that PG_A
+			 * is set.
+			 */
 			pmap_invalidate_page(pmap, va);
+		}
 		origpte = 0;
 	} else {
 		/*

Modified: head/sys/arm64/arm64/pmap.c
==============================================================================
--- head/sys/arm64/arm64/pmap.c	Sat Jan  4 19:29:25 2020	(r356353)
+++ head/sys/arm64/arm64/pmap.c	Sat Jan  4 19:50:25 2020	(r356354)
@@ -3449,8 +3449,10 @@ havel3:
 			 */
 			if (pmap_pte_dirty(orig_l3))
 				vm_page_dirty(om);
-			if ((orig_l3 & ATTR_AF) != 0)
+			if ((orig_l3 & ATTR_AF) != 0) {
+				pmap_invalidate_page(pmap, va);
 				vm_page_aflag_set(om, PGA_REFERENCED);
+			}
 			CHANGE_PV_LIST_LOCK_TO_PHYS(&lock, opa);
 			pv = pmap_pvh_remove(&om->md, pmap, va);
 			if ((m->oflags & VPO_UNMANAGED) != 0)
@@ -3460,8 +3462,11 @@ havel3:
 			    ((om->flags & PG_FICTITIOUS) != 0 ||
 			    TAILQ_EMPTY(&pa_to_pvh(opa)->pv_list)))
 				vm_page_aflag_clear(om, PGA_WRITEABLE);
+		} else {
+			KASSERT((orig_l3 & ATTR_AF) != 0,
+			    ("pmap_enter: unmanaged mapping lacks ATTR_AF"));
+			pmap_invalidate_page(pmap, va);
 		}
-		pmap_invalidate_page(pmap, va);
 		orig_l3 = 0;
 	} else {
 		/*

Modified: head/sys/i386/i386/pmap.c
==============================================================================
--- head/sys/i386/i386/pmap.c	Sat Jan  4 19:29:25 2020	(r356353)
+++ head/sys/i386/i386/pmap.c	Sat Jan  4 19:50:25 2020	(r356354)
@@ -3798,8 +3798,10 @@ __CONCAT(PMTYPE, enter)(pmap_t pmap, vm_offset_t va, v
 			 */
 			if ((origpte & (PG_M | PG_RW)) == (PG_M | PG_RW))
 				vm_page_dirty(om);
-			if ((origpte & PG_A) != 0)
+			if ((origpte & PG_A) != 0) {
+				pmap_invalidate_page_int(pmap, va);
 				vm_page_aflag_set(om, PGA_REFERENCED);
+			}
 			pv = pmap_pvh_remove(&om->md, pmap, va);
 			KASSERT(pv != NULL,
 			    ("pmap_enter: no PV entry for %#x", va));
@@ -3810,9 +3812,13 @@ __CONCAT(PMTYPE, enter)(pmap_t pmap, vm_offset_t va, v
 			    ((om->flags & PG_FICTITIOUS) != 0 ||
 			    TAILQ_EMPTY(&pa_to_pvh(opa)->pv_list)))
 				vm_page_aflag_clear(om, PGA_WRITEABLE);
-		}
-		if ((origpte & PG_A) != 0)
+		} else {
+			/*
+			 * Since this mapping is unmanaged, assume that PG_A
+			 * is set.
+			 */
 			pmap_invalidate_page_int(pmap, va);
+		}
 		origpte = 0;
 	} else {
 		/*

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