265 lines
7.2 KiB
C
265 lines
7.2 KiB
C
/* $OpenBSD: tib.h,v 1.10 2023/12/08 19:14:36 miod Exp $ */
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/*
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* Copyright (c) 2011,2014 Philip Guenther <guenther@openbsd.org>
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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/*
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* Thread Information Block (TIB) and Thread Local Storage (TLS) handling
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* (the TCB, Thread Control Block, is part of the TIB)
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*/
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#ifndef _TIB_H_
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#define _TIB_H_
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#include <sys/types.h>
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#include <machine/tcb.h>
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#include <stddef.h>
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/*
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* This header defines struct tib and at least eight macros:
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* TLS_VARIANT
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* Either 1 or 2 (Actually defined by <machine/tcb.h>)
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*
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* TCB_SET(tcb)
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* Set the TCB pointer for this thread to 'tcb'
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*
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* TCB_GET()
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* Return the TCB pointer for this thread
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*
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* TCB_TO_TIB(tcb)
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* Given a TCB pointer, return the matching TIB pointer
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*
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* TIB_TO_TCB(tib)
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* Given a TIB pointer, return the matching TCB pointer
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*
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* TIB_INIT(tib, dtv, thread)
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* Initializes a TIB for a new thread, using the supplied
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* values for its dtv and thread pointers
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*
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* TIB_GET()
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* Short-hand for TCB_TO_TIB(TCB_GET())
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*
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* TIB_EXTRA_ALIGN
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* On TLS variant 2 archs, what alignment is sufficient
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* for the extra space that will be used for struct pthread?
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*
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* The following functions are provided by either ld.so (dynamic) or
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* libc (static) for allocating and freeing a common memory block that
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* will hold both the TIB and the pthread structure:
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* _dl_allocate_tib(sizeof(struct pthread))
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* Allocates a combined TIB and pthread memory region.
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* The argument is the amount of space to reserve
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* for the pthread structure. Returns a pointer to
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* the TIB inside the allocated block.
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*
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* _dl_free_tib(tib, sizeof(struct pthread))
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* Frees a TIB and pthread block previously allocated
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* with _dl_allocate_tib(). Must be passed the return
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* value of that previous call.
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*/
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/*
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* Regarding <machine/tcb.h>:
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* - it must define the TLS_VARIANT macro
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* - it may define TCB_OFFSET if the TCB address in the kernel and/or
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* register is offset from the actual TCB address. TCB_OFFSET > 0
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* means the kernel/register points to *after* the real data.
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* - if there's a faster way to get or set the TCB pointer for the thread
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* than the __{get,set}_tcb() syscalls, it should define either or both
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* the TCB_{GET,SET} macros to do so.
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*/
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/* All archs but mips64 have fast TCB_GET() and don't need caching */
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#ifndef __mips64__
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# define TCB_HAVE_MD_GET 1
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#endif
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#ifdef TCB_SET
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# define TCB_HAVE_MD_SET 1
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#else
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# define TCB_SET(tcb) __set_tcb(tcb)
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#endif
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#ifndef TCB_OFFSET
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# define TCB_OFFSET 0
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#endif
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/*
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* tib_cantcancel values is non-zero if the thread should skip all
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* cancellation processing
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*/
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#define CANCEL_DISABLED 1
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#define CANCEL_DYING 2
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/*
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* tib_cancel_point is non-zero if we're in a cancel point; its modified
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* by the cancel point code and read by the cancellation signal handler
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*/
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#define CANCEL_POINT 1
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#define CANCEL_POINT_DELAYED 2
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#if TLS_VARIANT == 1
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/*
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* ABI specifies that the static TLS data starts two words after the
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* (notional) thread pointer, with the first of those two words being
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* the TLS dtv pointer. The other (second) word is reserved for the
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* implementation, so we place the pointer to the thread structure there,
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* but we place our actual thread bits before the TCB, at negative offsets
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* from the TCB pointer. Ergo, memory is laid out, low to high, as:
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*
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* [pthread structure]
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* TIB {
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* ...cancelation and other int-sized info...
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* int errno
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* void *locale
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* TCB (- TCB_OFFSET) {
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* void *dtv
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* struct pthread *thread
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* }
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* }
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* static TLS data
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*/
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struct tib {
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void *tib_atexit;
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int tib_thread_flags; /* internal to libpthread */
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pid_t tib_tid;
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int tib_cantcancel;
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int tib_cancel_point;
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int tib_canceled;
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int tib_errno;
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void *tib_locale;
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#ifdef __powerpc64__
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void *tib_thread;
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void *tib_dtv; /* internal to the runtime linker */
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#else
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void *tib_dtv; /* internal to the runtime linker */
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void *tib_thread;
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#endif
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};
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#elif TLS_VARIANT == 2
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/*
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* ABI specifies that the static TLS data occupies the memory before
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* the TCB pointer, at negative offsets, and that on i386 and amd64
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* the word the TCB points to contains a pointer to itself. So,
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* we place errno and our thread bits after that. Memory is laid
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* out, low to high, as:
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* static TLS data
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* TIB {
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* TCB (- TCB_OFFSET) {
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* self pointer [i386/amd64 only]
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* void *dtv
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* }
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* struct pthread *thread
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* void *locale
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* int errno
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* ...cancelation and other int-sized info...
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* }
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* [pthread structure]
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*/
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struct tib {
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#if defined(__i386) || defined(__amd64)
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struct tib *__tib_self;
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# define __tib_tcb __tib_self
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#endif
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void *tib_dtv; /* internal to the runtime linker */
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void *tib_thread;
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void *tib_locale;
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int tib_errno;
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int tib_canceled;
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int tib_cancel_point;
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int tib_cantcancel;
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pid_t tib_tid;
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int tib_thread_flags; /* internal to libpthread */
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void *tib_atexit;
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};
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#if defined(__i386) || defined(__amd64)
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# define _TIB_PREP(tib) \
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((void)((tib)->__tib_self = (tib)))
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#endif
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#define TIB_EXTRA_ALIGN sizeof(void *)
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#else
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# error "unknown TLS variant"
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#endif
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/* nothing to do by default */
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#ifndef _TIB_PREP
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# define _TIB_PREP(tib) ((void)0)
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#endif
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#define TIB_INIT(tib, dtv, thread) do { \
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(tib)->tib_thread = (thread); \
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(tib)->tib_atexit = NULL; \
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(tib)->tib_locale = NULL; \
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(tib)->tib_cantcancel = 0; \
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(tib)->tib_cancel_point = 0; \
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(tib)->tib_canceled = 0; \
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(tib)->tib_dtv = (dtv); \
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(tib)->tib_errno = 0; \
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(tib)->tib_thread_flags = 0; \
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_TIB_PREP(tib); \
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} while (0)
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#ifndef __tib_tcb
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# define __tib_tcb tib_dtv
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#endif
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#define _TIBO_TCB (offsetof(struct tib, __tib_tcb) + TCB_OFFSET)
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#define TCB_TO_TIB(tcb) ((struct tib *)((char *)(tcb) - _TIBO_TCB))
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#define TIB_TO_TCB(tib) ((char *)(tib) + _TIBO_TCB)
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#define TIB_GET() TCB_TO_TIB(TCB_GET())
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__BEGIN_DECLS
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struct dl_info;
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struct dl_phdr_info;
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struct dl_cb_0 {
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void *(*dl_allocate_tib)(size_t);
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void (*dl_free_tib)(void *, size_t);
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void (*dl_clean_boot)(void);
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void *(*dlopen)(const char *, int);
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int (*dlclose)(void *);
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void *(*dlsym)(void *, const char *);
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int (*dladdr)(const void *, struct dl_info *);
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int (*dlctl)(void *, int, void *);
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char *(*dlerror)(void);
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int (*dl_iterate_phdr)(int (*)(struct dl_phdr_info *,
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size_t, void *), void *);
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};
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#define DL_CB_CUR 0
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typedef struct dl_cb_0 dl_cb;
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/* type of function passed to init functions that returns a dl_cb */
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typedef const void *dl_cb_cb(int _version);
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void *_dl_allocate_tib(size_t _extra) __dso_public;
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void _dl_free_tib(void *_tib, size_t _extra) __dso_public;
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/* The actual syscalls */
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void *__get_tcb(void);
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void __set_tcb(void *_tcb);
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__END_DECLS
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#endif /* _TIB_H_ */
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