freebsd-skq/lib/libc/arm/gen/arm_initfini.c
Andrew Turner 8e03dd5926 Finish pulling in the NetBSD setjmp/longjmp updates on ARM.
Store/restore the VFP registers in setjmp/longjmp on ARM EABI if VFP is
enabled in the kernel. It checks the hw.floatingpoint sysctl to see if
floating-point is available and uses this to determine if it should store
them. If it does it uses a different magic value so longjmp is able to know
if it should load them.
2013-06-07 22:01:06 +00:00

79 lines
2.7 KiB
C

/*-
* Copyright (c) 2013 The NetBSD Foundation, Inc.
* Copyright (c) 2013 Andrew Turner
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Matt Thomas of 3am Software Foundry.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* Bases on NetBSD lib/libc/arch/arm/misc/arm_initfini.c
* $NetBSD: arm_initfini.c,v 1.2 2013/01/31 06:47:55 matt Exp $
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
/*
* To properly implement setjmp/longjmp for the ARM AAPCS ABI, it has to be
* aware of whether there is a FPU is present or not. Regardless of whether
* the hard-float ABI is being used, setjmp needs to save D8-D15. But it can
* only do this if those instructions won't cause an exception.
*/
#include <sys/param.h>
#include <sys/sysctl.h>
#include <stdbool.h>
#include <stddef.h>
extern int __sysctl(int *name, u_int namelen, void *oldp, size_t *oldlenp,
void *newp, size_t newlen);
int _libc_arm_fpu_present;
static bool _libc_aapcs_initialized;
void _libc_aapcs_init(void) __attribute__((__constructor__, __used__));
void
_libc_aapcs_init(void)
{
int mib[2];
size_t len;
if (_libc_aapcs_initialized)
return;
mib[0] = CTL_HW;
mib[1] = HW_FLOATINGPT;
len = sizeof(_libc_arm_fpu_present);
if (__sysctl(mib, 2, &_libc_arm_fpu_present, &len, NULL, 0) == -1 ||
len != sizeof(_libc_arm_fpu_present)) {
/* sysctl failed, assume no vfp */
_libc_arm_fpu_present = 0;
}
_libc_aapcs_initialized = true;
}