xref: /netbsd-src/lib/libc/arch/arm/misc/arm_initfini.c (revision 8c98e4a90f85cbc83fc8b44517ec5df61223c0a5)
1 /*-
2  * Copyright (c) 2013 The NetBSD Foundation, Inc.
3  * All rights reserved.
4  *
5  * This code is derived from software contributed to The NetBSD Foundation
6  * by Matt Thomas of 3am Software Foundry.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
18  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
19  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
20  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
21  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
22  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
23  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
24  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
25  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
26  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
27  * POSSIBILITY OF SUCH DAMAGE.
28  */
29 
30 #include <sys/cdefs.h>
31 
32 __RCSID("$NetBSD: arm_initfini.c,v 1.2 2013/01/31 06:47:55 matt Exp $");
33 
34 /*
35  * To properly implement setjmp/longjmp for the ARM AAPCS ABI, it has to be
36  * aware of whether there is a FPU is present or not.  Regardless of whether
37  * the hard-float ABI is being used, setjmp needs to save D8-D15.  But it can
38  * only do this if those instructions won't cause an exception.
39  */
40 
41 #include <sys/param.h>
42 #include <sys/sysctl.h>
43 
44 #include <stdbool.h>
45 #include <stddef.h>
46 
47 int _libc_arm_fpu_present;
48 static bool _libc_aapcs_initialized;
49 
50 void	_libc_aapcs_init(void) __attribute__((__constructor__, __used__));
51 
52 void
53 _libc_aapcs_init(void)
54 {
55 	if (!_libc_aapcs_initialized) {
56 		size_t len = sizeof(_libc_arm_fpu_present);
57 		_libc_aapcs_initialized = true;
58 		(void)sysctlbyname("machdep.fpu_present",
59 		    &_libc_arm_fpu_present, &len, NULL, 0);
60 	}
61 }
62