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Date:      Wed, 9 May 2018 12:09:08 +0000 (UTC)
From:      Konstantin Belousov <kib@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r333405 - head/sys/amd64/amd64
Message-ID:  <201805091209.w49C987J011732@repo.freebsd.org>
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Author: kib
Date: Wed May  9 12:09:08 2018
New Revision: 333405
URL: https://svnweb.freebsd.org/changeset/base/333405

Log:
  Remove PG_U from the rest of the kernel pmap ptes.
  
  Supposedly, they PG_U bits there were set to easier making some kernel
  page accessible to userspace in-place.  Since it was not used for the
  whole existence of the amd64 pmap.c and current design of the shared
  pages prefers double-mapping over the in-place access, remove PG_U
  both from the direct map and KVA slots.
  
  Reviewed by:	alc, markj
  Sponsored by:	The FreeBSD Foundation
  MFC after:	1 week

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

Modified: head/sys/amd64/amd64/pmap.c
==============================================================================
--- head/sys/amd64/amd64/pmap.c	Wed May  9 12:03:40 2018	(r333404)
+++ head/sys/amd64/amd64/pmap.c	Wed May  9 12:09:08 2018	(r333405)
@@ -1011,8 +1011,7 @@ create_pagetables(vm_paddr_t *firstaddr)
 	/* And connect up the PD to the PDP (leaving room for L4 pages) */
 	pdp_p = (pdp_entry_t *)(KPDPphys + ptoa(KPML4I - KPML4BASE));
 	for (i = 0; i < nkpdpe; i++)
-		pdp_p[i + KPDPI] = (KPDphys + ptoa(i)) | X86_PG_RW | X86_PG_V |
-		    PG_U;
+		pdp_p[i + KPDPI] = (KPDphys + ptoa(i)) | X86_PG_RW | X86_PG_V;
 
 	/*
 	 * Now, set up the direct map region using 2MB and/or 1GB pages.  If
@@ -1038,7 +1037,7 @@ create_pagetables(vm_paddr_t *firstaddr)
 	}
 	for (j = 0; i < ndmpdp; i++, j++) {
 		pdp_p[i] = DMPDphys + ptoa(j);
-		pdp_p[i] |= X86_PG_RW | X86_PG_V | PG_U;
+		pdp_p[i] |= X86_PG_RW | X86_PG_V;
 	}
 
 	/*
@@ -1054,7 +1053,7 @@ create_pagetables(vm_paddr_t *firstaddr)
 			    bootaddr_rwx(i << PDRSHIFT);
 		for (i = 0; i < nkdmpde; i++)
 			pdp_p[i] = (DMPDkernphys + ptoa(i)) | X86_PG_RW |
-			    X86_PG_V | PG_U;
+			    X86_PG_V;
 	}
 
 	/* And recursively map PML4 to itself in order to get PTmap */
@@ -1065,13 +1064,13 @@ create_pagetables(vm_paddr_t *firstaddr)
 	/* Connect the Direct Map slot(s) up to the PML4. */
 	for (i = 0; i < ndmpdpphys; i++) {
 		p4_p[DMPML4I + i] = DMPDPphys + ptoa(i);
-		p4_p[DMPML4I + i] |= X86_PG_RW | X86_PG_V | PG_U;
+		p4_p[DMPML4I + i] |= X86_PG_RW | X86_PG_V;
 	}
 
 	/* Connect the KVA slots up to the PML4 */
 	for (i = 0; i < NKPML4E; i++) {
 		p4_p[KPML4BASE + i] = KPDPphys + ptoa(i);
-		p4_p[KPML4BASE + i] |= X86_PG_RW | X86_PG_V | PG_U;
+		p4_p[KPML4BASE + i] |= X86_PG_RW | X86_PG_V;
 	}
 }
 
@@ -2628,11 +2627,11 @@ pmap_pinit_pml4(vm_page_t pml4pg)
 	/* Wire in kernel global address entries. */
 	for (i = 0; i < NKPML4E; i++) {
 		pm_pml4[KPML4BASE + i] = (KPDPphys + ptoa(i)) | X86_PG_RW |
-		    X86_PG_V | PG_U;
+		    X86_PG_V;
 	}
 	for (i = 0; i < ndmpdpphys; i++) {
 		pm_pml4[DMPML4I + i] = (DMPDPphys + ptoa(i)) | X86_PG_RW |
-		    X86_PG_V | PG_U;
+		    X86_PG_V;
 	}
 
 	/* install self-referential address mapping entry(s) */

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