[src/trunk]: src/sys/arch/x86 Add an option to have a static kernel memory la...

[maxv <maxv%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/fa0e3d465d33
branches:  trunk
changeset: 995107:fa0e3d465d33
user:      maxv <maxv%NetBSD.org@localhost>
date:      Fri Dec 07 15:47:11 2018 +0000

description:
Add an option to have a static kernel memory layout. This option is
disabled by default - that is to say, KASLR remains enabled by default.

diffstat:

 sys/arch/x86/conf/files.x86 |   5 ++++-
 sys/arch/x86/x86/pmap.c     |  11 +++++++++--
 2 files changed, 13 insertions(+), 3 deletions(-)

diffs (65 lines):

diff -r a0c16c6a0b25 -r fa0e3d465d33 sys/arch/x86/conf/files.x86
--- a/sys/arch/x86/conf/files.x86       Fri Dec 07 14:59:19 2018 +0000
+++ b/sys/arch/x86/conf/files.x86       Fri Dec 07 15:47:11 2018 +0000
@@ -1,4 +1,4 @@
-#      $NetBSD: files.x86,v 1.103 2018/07/16 06:18:31 maxv Exp $
+#      $NetBSD: files.x86,v 1.104 2018/12/07 15:47:11 maxv Exp $
 
 # options for MP configuration through the MP spec
 defflag opt_mpbios.h MPBIOS MPDEBUG MPBIOS_SCANPCI
@@ -17,6 +17,9 @@
 # To be able to test for NetBSD/xen in shared files
 defflag        opt_xen.h               DO_NOT_DEFINE
 
+# Option to have a static kernel memory layout
+defflag opt_kaslr.h    NO_X86_ASLR
+
 defflag        SVS
 
 define  cpubus { [apid = -1] }
diff -r a0c16c6a0b25 -r fa0e3d465d33 sys/arch/x86/x86/pmap.c
--- a/sys/arch/x86/x86/pmap.c   Fri Dec 07 14:59:19 2018 +0000
+++ b/sys/arch/x86/x86/pmap.c   Fri Dec 07 15:47:11 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: pmap.c,v 1.312 2018/11/19 20:44:51 maxv Exp $  */
+/*     $NetBSD: pmap.c,v 1.313 2018/12/07 15:47:11 maxv Exp $  */
 
 /*
  * Copyright (c) 2008, 2010, 2016, 2017 The NetBSD Foundation, Inc.
@@ -130,7 +130,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: pmap.c,v 1.312 2018/11/19 20:44:51 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: pmap.c,v 1.313 2018/12/07 15:47:11 maxv Exp $");
 
 #include "opt_user_ldt.h"
 #include "opt_lockdebug.h"
@@ -138,6 +138,7 @@
 #include "opt_xen.h"
 #include "opt_svs.h"
 #include "opt_kasan.h"
+#include "opt_kaslr.h"
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -1360,6 +1361,9 @@
 
        /* Select a hole. */
        cpu_earlyrng(&hole, sizeof(hole));
+#ifdef NO_X86_ASLR
+       hole = 0;
+#endif
        hole %= nholes;
        startsl = holes[hole].start;
        endsl = holes[hole].end;
@@ -1367,6 +1371,9 @@
 
        /* Select an area within the hole. */
        cpu_earlyrng(&va, sizeof(va));
+#ifdef NO_X86_ASLR
+       va = 0;
+#endif
        winsize = ((endsl - startsl) * NBPD_L4) - sz;
        va %= winsize;
        va = rounddown(va, align);