freebsd-dev/lib/libc/arm/sys/__vdso_gettc.c
Konstantin Belousov 66fa67c7f7 Do not compile ARMv6 instructions on ARMv4/v5. Although clang is fine
with mrrc, gcc is not.  The disabled code is not executed on ARMv4
anyway.

Reported and reviewed by:	ian
Sponsored by:	The FreeBSD Foundation
2015-12-24 22:13:52 +00:00

87 lines
2.5 KiB
C

/*-
* Copyright (c) 2015 The FreeBSD Foundation
*
* This software was developed by Konstantin Belousov
* under sponsorship from the FreeBSD Foundation.
*
* 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 AUTHOR 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 AUTHOR 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/types.h>
#include <sys/elf.h>
#include <sys/time.h>
#include <sys/vdso.h>
#include <machine/cpufunc.h>
#include <machine/acle-compat.h>
#include "libc_private.h"
#if __ARM_ARCH >= 6
static inline uint64_t
cp15_cntvct_get(void)
{
uint64_t reg;
__asm __volatile("mrrc\tp15, 1, %Q0, %R0, c14" : "=r" (reg));
return (reg);
}
static inline uint64_t
cp15_cntpct_get(void)
{
uint64_t reg;
__asm __volatile("mrrc\tp15, 0, %Q0, %R0, c14" : "=r" (reg));
return (reg);
}
#endif
#pragma weak __vdso_gettc
u_int
__vdso_gettc(const struct vdso_timehands *th)
{
uint64_t val;
#if __ARM_ARCH >= 6
/*
* Userspace gettimeofday() is only enabled on ARMv7 CPUs, but
* libc is compiled for ARMv6. Due to clang issues, .arch
* armv7-a directive does not work.
*/
__asm __volatile(".word\t0xf57ff06f" : : : "memory"); /* isb */
val = th->th_physical == 0 ? cp15_cntvct_get() : cp15_cntpct_get();
#else
val = 0;
#endif
return (val);
}
#pragma weak __vdso_gettimekeep
int
__vdso_gettimekeep(struct vdso_timekeep **tk)
{
return (_elf_aux_info(AT_TIMEKEEP, tk, sizeof(*tk)));
}