1*11be35a1SLionel Sambuc /* $NetBSD: exec_prot_support.c,v 1.1 2011/07/18 23:16:09 jym Exp $ */
2*11be35a1SLionel Sambuc
3*11be35a1SLionel Sambuc /*-
4*11be35a1SLionel Sambuc * Copyright (c) 2011 The NetBSD Foundation, Inc.
5*11be35a1SLionel Sambuc * All rights reserved.
6*11be35a1SLionel Sambuc *
7*11be35a1SLionel Sambuc * This code is derived from software contributed to The NetBSD Foundation
8*11be35a1SLionel Sambuc * by Jean-Yves Migeon.
9*11be35a1SLionel Sambuc *
10*11be35a1SLionel Sambuc * Redistribution and use in source and binary forms, with or without
11*11be35a1SLionel Sambuc * modification, are permitted provided that the following conditions
12*11be35a1SLionel Sambuc * are met:
13*11be35a1SLionel Sambuc * 1. Redistributions of source code must retain the above copyright
14*11be35a1SLionel Sambuc * notice, this list of conditions and the following disclaimer.
15*11be35a1SLionel Sambuc * 2. Redistributions in binary form must reproduce the above copyright
16*11be35a1SLionel Sambuc * notice, this list of conditions and the following disclaimer in the
17*11be35a1SLionel Sambuc * documentation and/or other materials provided with the distribution.
18*11be35a1SLionel Sambuc *
19*11be35a1SLionel Sambuc * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20*11be35a1SLionel Sambuc * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21*11be35a1SLionel Sambuc * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22*11be35a1SLionel Sambuc * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23*11be35a1SLionel Sambuc * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24*11be35a1SLionel Sambuc * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25*11be35a1SLionel Sambuc * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26*11be35a1SLionel Sambuc * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27*11be35a1SLionel Sambuc * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28*11be35a1SLionel Sambuc * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29*11be35a1SLionel Sambuc * POSSIBILITY OF SUCH DAMAGE.
30*11be35a1SLionel Sambuc */
31*11be35a1SLionel Sambuc
32*11be35a1SLionel Sambuc #include <sys/cdefs.h>
33*11be35a1SLionel Sambuc __RCSID("$NetBSD: exec_prot_support.c,v 1.1 2011/07/18 23:16:09 jym Exp $");
34*11be35a1SLionel Sambuc
35*11be35a1SLionel Sambuc #include <stdlib.h>
36*11be35a1SLionel Sambuc #include <sys/sysctl.h>
37*11be35a1SLionel Sambuc
38*11be35a1SLionel Sambuc #include "../../common/exec_prot.h"
39*11be35a1SLionel Sambuc
40*11be35a1SLionel Sambuc /*
41*11be35a1SLionel Sambuc * Support for executable space protection has always been erratic under i386.
42*11be35a1SLionel Sambuc * Originally IA-32 can't do per-page execute permission, so it is
43*11be35a1SLionel Sambuc * implemented using different executable segments for %cs (code segment).
44*11be35a1SLionel Sambuc * This only allows coarse grained protection, especially when memory starts
45*11be35a1SLionel Sambuc * being fragmented.
46*11be35a1SLionel Sambuc * Later, PAE was introduced together with a NX/XD bit in the page table
47*11be35a1SLionel Sambuc * entry to offer per-page permission.
48*11be35a1SLionel Sambuc */
49*11be35a1SLionel Sambuc int
exec_prot_support(void)50*11be35a1SLionel Sambuc exec_prot_support(void)
51*11be35a1SLionel Sambuc {
52*11be35a1SLionel Sambuc int pae;
53*11be35a1SLionel Sambuc size_t pae_len = sizeof(pae);
54*11be35a1SLionel Sambuc
55*11be35a1SLionel Sambuc if (sysctlbyname("machdep.pae", &pae, &pae_len, NULL, 0) == -1)
56*11be35a1SLionel Sambuc return PARTIAL_XP;
57*11be35a1SLionel Sambuc
58*11be35a1SLionel Sambuc if (pae == 1) {
59*11be35a1SLionel Sambuc if (system("cpuctl identify 0 | grep -q NOX") == 0 ||
60*11be35a1SLionel Sambuc system("cpuctl identify 0 | grep -q XD") == 0)
61*11be35a1SLionel Sambuc return PERPAGE_XP;
62*11be35a1SLionel Sambuc }
63*11be35a1SLionel Sambuc
64*11be35a1SLionel Sambuc return PARTIAL_XP;
65*11be35a1SLionel Sambuc }
66