sys/x86/include/tls.h

root/sys/x86/include/tls.h
/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (C) 2003 David Xu <davidxu@freebsd.org>
 * Copyright (c) 2001 Daniel Eischen <deischen@freebsd.org>
 * All rights reserved.
 *
 * 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. Neither the name of the author nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * 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.
 */

#ifndef _MACHINE_TLS_H_
#define _MACHINE_TLS_H_

#include <x86/sysarch.h>

#define TLS_VARIANT_II

struct pthread;

struct dtv_slot {
        char                    *dtvs_tls;
};

struct dtv {
        uintptr_t               dtv_gen;
        uintptr_t               dtv_size;
        struct dtv_slot         dtv_slots[];
};

/*
 * Variant II tcb, first two members are required by rtld,
 * %fs (amd64) / %gs (i386) points to the structure.
 */
struct tcb {
        struct tcb              *tcb_self;      /* required by rtld */
        struct dtv              *tcb_dtv;       /* required by rtld */
        struct pthread          *tcb_thread;
};

#define TLS_DTV_OFFSET  0
#ifdef __amd64__
#define TLS_TCB_ALIGN   16
#else
#define TLS_TCB_ALIGN   4
#endif
#define TLS_TCB_SIZE    sizeof(struct tcb)
#define TLS_TP_OFFSET   0

static __inline void
_tcb_set(struct tcb *tcb)
{
#ifdef __amd64__
        amd64_set_tlsbase(tcb);
#else
        i386_set_gsbase(tcb);
#endif
}

static __inline struct tcb *
_tcb_get(void)
{
        struct tcb *tcb;

#ifdef __amd64__
        __asm __volatile("movq %%fs:0, %0" : "=r" (tcb));
#else
        __asm __volatile("movl %%gs:0, %0" : "=r" (tcb));
#endif
        return (tcb);
}

#endif /* !_MACHINE_TLS_H_ */
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