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arm_initfini.c revision 1.4 
      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 1.4 2013/08/16 17:09:27 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 static bool _libc_aapcs_initialized;
     51 
     52 void	_libc_aapcs_init(void) __attribute__((__constructor__, __used__));
     53 
     54 void
     55 _libc_aapcs_init(void)
     56 {
     57 	if (!_libc_aapcs_initialized) {
     58 		size_t len = sizeof(_libc_arm_fpu_present);
     59 		_libc_aapcs_initialized = true;
     60 		(void)sysctlbyname("machdep.fpu_present",
     61 		    &_libc_arm_fpu_present, &len, NULL, 0);
     62 	}
     63 }
     64