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
56 lines
1.8 KiB
C
56 lines
1.8 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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*
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* Copyright (c) 2005 David Xu <davidxu@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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*
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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. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 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 <sys/_tls_variant_i.h>
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#include <machine/sysarch.h>
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#define TLS_DTV_OFFSET 0
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#define TLS_TCB_ALIGN 8
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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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sysarch(ARM_SET_TP, tcb);
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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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__asm __volatile("mrc p15, 0, %0, c13, c0, 3" \
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: "=r" (tcb));
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return (tcb);
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}
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#endif /* !_MACHINE_TLS_H_ */
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