path: root/lib/libc/mips/gen/_get_tp.c

/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2021 The FreeBSD Foundation
 *
 * This software were 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 <string.h>
#include <stdint.h>
#include <machine/sysarch.h>
#include <machine/tls.h>

#include "libc_private.h"

#ifdef __mips_n64
static void *
_mips_get_tls(void)
{
	uint64_t _rv;

	__asm__ __volatile__ (
	    ".set\tpush\n\t"
	    ".set\tmips64r2\n\t"
	    "rdhwr\t%0, $29\n\t"
	    ".set\tpop"
	    : "=r" (_rv));
	/*
	 * XXXSS See 'git show c6be4f4d2d1b71c04de5d3bbb6933ce2dbcdb317'
	 *
	 * Remove the offset since this really a request to get the TLS
	 * pointer via sysarch() (in theory).  Of course, this may go away
	 * once the TLS code is rewritten.
	 */
	_rv = _rv - TLS_TP_OFFSET - TLS_TCB_SIZE;

	return (void *)_rv;
}

#else /* mips 32 */

static void *
_mips_get_tls(void)
{
	uint32_t _rv;

	__asm__ __volatile__ (
	    ".set\tpush\n\t"
	    ".set\tmips32r2\n\t"
	    "rdhwr\t%0, $29\n\t"
	    ".set\tpop"
	    : "=r" (_rv));
	/*
	 * XXXSS See 'git show c6be4f4d2d1b71c04de5d3bbb6933ce2dbcdb317'
	 *
	 * Remove the offset since this really a request to get the TLS
	 * pointer via sysarch() (in theory).  Of course, this may go away
	 * once the TLS code is rewritten.
	 */
	_rv = _rv - TLS_TP_OFFSET - TLS_TCB_SIZE;

	return (void *)_rv;
}
#endif /* ! __mips_n64 */

void *
_get_tp(void)
{
	void *res;

#ifdef TLS_USE_SYSARCH
	sysarch(MIPS_GET_TLS, &res);
#else
	res = _mips_get_tls();
#endif
	return (res);
}