1*ca453df6Sjym /* $NetBSD: exec_prot_support.c,v 1.1 2011/07/18 23:16:09 jym Exp $ */
2*ca453df6Sjym
3*ca453df6Sjym /*-
4*ca453df6Sjym * Copyright (c) 2011 The NetBSD Foundation, Inc.
5*ca453df6Sjym * All rights reserved.
6*ca453df6Sjym *
7*ca453df6Sjym * This code is derived from software contributed to The NetBSD Foundation
8*ca453df6Sjym * by Jean-Yves Migeon.
9*ca453df6Sjym *
10*ca453df6Sjym * Redistribution and use in source and binary forms, with or without
11*ca453df6Sjym * modification, are permitted provided that the following conditions
12*ca453df6Sjym * are met:
13*ca453df6Sjym * 1. Redistributions of source code must retain the above copyright
14*ca453df6Sjym * notice, this list of conditions and the following disclaimer.
15*ca453df6Sjym * 2. Redistributions in binary form must reproduce the above copyright
16*ca453df6Sjym * notice, this list of conditions and the following disclaimer in the
17*ca453df6Sjym * documentation and/or other materials provided with the distribution.
18*ca453df6Sjym *
19*ca453df6Sjym * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20*ca453df6Sjym * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21*ca453df6Sjym * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22*ca453df6Sjym * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23*ca453df6Sjym * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24*ca453df6Sjym * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25*ca453df6Sjym * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26*ca453df6Sjym * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27*ca453df6Sjym * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28*ca453df6Sjym * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29*ca453df6Sjym * POSSIBILITY OF SUCH DAMAGE.
30*ca453df6Sjym */
31*ca453df6Sjym
32*ca453df6Sjym #include <sys/cdefs.h>
33*ca453df6Sjym __RCSID("$NetBSD: exec_prot_support.c,v 1.1 2011/07/18 23:16:09 jym Exp $");
34*ca453df6Sjym
35*ca453df6Sjym #include <stdlib.h>
36*ca453df6Sjym #include <sys/sysctl.h>
37*ca453df6Sjym
38*ca453df6Sjym #include "../../common/exec_prot.h"
39*ca453df6Sjym
40*ca453df6Sjym /*
41*ca453df6Sjym * Support for executable space protection has always been erratic under i386.
42*ca453df6Sjym * Originally IA-32 can't do per-page execute permission, so it is
43*ca453df6Sjym * implemented using different executable segments for %cs (code segment).
44*ca453df6Sjym * This only allows coarse grained protection, especially when memory starts
45*ca453df6Sjym * being fragmented.
46*ca453df6Sjym * Later, PAE was introduced together with a NX/XD bit in the page table
47*ca453df6Sjym * entry to offer per-page permission.
48*ca453df6Sjym */
49*ca453df6Sjym int
exec_prot_support(void)50*ca453df6Sjym exec_prot_support(void)
51*ca453df6Sjym {
52*ca453df6Sjym int pae;
53*ca453df6Sjym size_t pae_len = sizeof(pae);
54*ca453df6Sjym
55*ca453df6Sjym if (sysctlbyname("machdep.pae", &pae, &pae_len, NULL, 0) == -1)
56*ca453df6Sjym return PARTIAL_XP;
57*ca453df6Sjym
58*ca453df6Sjym if (pae == 1) {
59*ca453df6Sjym if (system("cpuctl identify 0 | grep -q NOX") == 0 ||
60*ca453df6Sjym system("cpuctl identify 0 | grep -q XD") == 0)
61*ca453df6Sjym return PERPAGE_XP;
62*ca453df6Sjym }
63*ca453df6Sjym
64*ca453df6Sjym return PARTIAL_XP;
65*ca453df6Sjym }
66