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1a62e9bc00
The header exports the following: - Definition of struct tcb. - Helpers to get/set the tcb for the current thread. - TLS_TCB_SIZE (size of TCB) - TLS_TCB_ALIGN (alignment of TCB) - TLS_VARIANT_I or TLS_VARIANT_II - TLS_DTV_OFFSET (bias of pointers in dtv[]) - TLS_TP_OFFSET (bias of "thread pointer" relative to TCB) Note that TLS_TP_OFFSET does not account for if the unbiased thread pointer points to the start of the TCB (arm and x86) or the end of the TCB (MIPS, PowerPC, and RISC-V). Note also that for amd64, the struct tcb does not include the unused tcb_spare field included in the current structure in libthr. libthr does not use this field, and the existing calls in libc and rtld that allocate a TCB for amd64 assume it is the size of 3 Elf_Addr's (and thus do not allocate room for tcb_spare). A <sys/_tls_variant_i.h> header is used by architectures using Variant I TLS which uses a common struct tcb. Reviewed by: kib (older version of x86/tls.h), jrtc27 Sponsored by: The University of Cambridge, Google Inc. Differential Revision: https://reviews.freebsd.org/D33351
81 lines
2.3 KiB
C
81 lines
2.3 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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*
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* Copyright (C) 2003 David Xu <davidxu@freebsd.org>
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* Copyright (c) 2001 Daniel Eischen <deischen@freebsd.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Neither the name of the author nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#ifndef _MACHINE_TLS_H_
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#define _MACHINE_TLS_H_
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#include <x86/sysarch.h>
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#define TLS_VARIANT_II
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struct pthread;
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/*
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* Variant II tcb, first two members are required by rtld,
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* %fs (amd64) / %gs (i386) points to the structure.
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*/
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struct tcb {
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struct tcb *tcb_self; /* required by rtld */
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uintptr_t *tcb_dtv; /* required by rtld */
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struct pthread *tcb_thread;
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};
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#define TLS_DTV_OFFSET 0
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#ifdef __amd64__
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#define TLS_TCB_ALIGN 16
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#else
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#define TLS_TCB_ALIGN 4
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#endif
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#define TLS_TCB_SIZE sizeof(struct tcb)
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#define TLS_TP_OFFSET 0
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static __inline void
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_tcb_set(struct tcb *tcb)
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{
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#ifdef __amd64__
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amd64_set_fsbase(tcb);
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#else
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i386_set_gsbase(tcb);
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#endif
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}
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static __inline struct tcb *
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_tcb_get(void)
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{
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struct tcb *tcb;
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#ifdef __amd64__
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__asm __volatile("movq %%fs:0, %0" : "=r" (tcb));
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#else
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__asm __volatile("movl %%gs:0, %0" : "=r" (tcb));
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#endif
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return (tcb);
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}
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#endif /* !_MACHINE_TLS_H_ */
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