xref: /minix3/lib/libc/arch/arm/misc/arm_initfini.c (revision 0a6a1f1d05b60e214de2f05a7310ddd1f0e590e7)
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 1.7 2013/09/08 13:15:53 matt Exp $");
33 
34 #include "namespace.h"
35 
36 /*
37  * To properly implement setjmp/longjmp for the ARM AAPCS ABI, it has to be
38  * aware of whether there is a FPU is present or not.  Regardless of whether
39  * the hard-float ABI is being used, setjmp needs to save D8-D15.  But it can
40  * only do this if those instructions won't cause an exception.
41  */
42 
43 #include <sys/param.h>
44 #include <sys/sysctl.h>
45 
46 #include <stdbool.h>
47 #include <stddef.h>
48 
49 __dso_hidden int _libc_arm_fpu_present;
50 #ifndef __ARM_ARCH_EXT_IDIV__
51 __dso_hidden int _libc_arm_hwdiv_present;
52 #endif
53 static bool _libc_aapcs_initialized;
54 
55 void	_libc_aapcs_init(void) __attribute__((__constructor__, __used__));
56 
57 void __section(".text.startup")
58 _libc_aapcs_init(void)
59 {
60 	if (!_libc_aapcs_initialized) {
61 #if !defined(__minix)
62 		size_t len = sizeof(_libc_arm_fpu_present);
63 #endif
64 		_libc_aapcs_initialized = true;
65 #if !defined(__minix)
66 		(void)sysctlbyname("machdep.fpu_present",
67 		    &_libc_arm_fpu_present, &len, NULL, 0);
68 #ifndef __ARM_ARCH_EXT_IDIV__
69 		(void)sysctlbyname("machdep.hwdiv_present",
70 		    &_libc_arm_hwdiv_present, &len, NULL, 0);
71 #endif
72 #endif /* !defined(__minix) */
73 	}
74 }
75