crtbrand.c revision 274400 
1/*-
2 * Copyright 2000 David E. O'Brien, John D. Polstra.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#include <sys/cdefs.h>
27__FBSDID("$FreeBSD: releng/10.1/lib/csu/common/crtbrand.c 274400 2014-11-11 19:51:27Z gjb $");
28
29#include <sys/param.h>
30#include "notes.h"
31
32/*
33 * Special ".note" entry specifying the ABI version.  See
34 * http://www.netbsd.org/Documentation/kernel/elf-notes.html
35 * for more information.
36 *
37 * For all arches except sparc, gcc emits the section directive for the
38 * following struct with a PROGBITS type.  However, newer versions of binutils
39 * (after 2.16.90) require the section to be of NOTE type, to guarantee that the
40 * .note.ABI-tag section correctly ends up in the first page of the final
41 * executable.
42 *
43 * Unfortunately, there is no clean way to tell gcc to use another section type,
44 * so this C file (or the C file that includes it) must be compiled in multiple
45 * steps:
46 *
47 * - Compile the .c file to a .s file.
48 * - Edit the .s file to change the 'progbits' type to 'note', for the section
49 *   directive that defines the .note.ABI-tag section.
50 * - Compile the .s file to an object file.
51 *
52 * These steps are done in the invididual Makefiles for each applicable arch.
53 */
54static const struct {
55	int32_t	namesz;
56	int32_t	descsz;
57	int32_t	type;
58	char	name[sizeof(NOTE_FREEBSD_VENDOR)];
59	int32_t	desc;
60} abitag __attribute__ ((section (NOTE_SECTION), aligned(4))) __used = {
61	.namesz = sizeof(NOTE_FREEBSD_VENDOR),
62	.descsz = sizeof(int32_t),
63	.type = ABI_NOTETYPE,
64	.name = NOTE_FREEBSD_VENDOR,
65	.desc = 1001000
66};
67