91 lines
2.9 KiB
C
91 lines
2.9 KiB
C
/* $OpenBSD: tib.c,v 1.3 2022/12/27 17:10:06 jmc Exp $ */
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/*
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* Copyright (c) 2016 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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#include <tib.h>
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#ifndef PIC
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# include <stdlib.h> /* posix_memalign and free */
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#endif
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#define ELF_ROUND(x,malign) (((x) + (malign)-1) & ~((malign)-1))
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/*
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* The functions here are weak so that the ld.so versions are used
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* in dynamic links, whether or not libc is static
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*/
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void *_dl_allocate_tib(size_t _extra) __attribute__((weak));
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void _dl_free_tib(void *_tib, size_t _extra) __attribute__((weak));
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/*
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* Allocate a TIB for passing to __tfork for a new thread. 'extra'
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* is the amount of space to allocate on the side of the TIB opposite
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* of the TLS data: before the TIB for variant 1 and after the TIB
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* for variant 2. If non-zero, tib_thread is set to point to that area.
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*/
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void *
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_dl_allocate_tib(size_t extra)
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{
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#ifdef PIC
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return NULL; /* overridden by ld.so */
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#else
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void *base;
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char *thread;
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# if TLS_VARIANT == 1
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/* round up the extra size to align the TIB and TLS data after it */
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extra = (extra <= _static_tls_align_offset) ? 0 :
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ELF_ROUND(extra - _static_tls_align_offset, _static_tls_align);
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if (posix_memalign(&base, _static_tls_align, extra +
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_static_tls_align_offset + sizeof(struct tib) +
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_static_tls_size) != 0)
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return NULL;
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thread = base;
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base = (char *)base + extra;
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# elif TLS_VARIANT == 2
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/* round up the TIB size to align the extra area after it */
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if (posix_memalign(&base, _static_tls_align,
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_static_tls_align_offset + _static_tls_size +
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ELF_ROUND(sizeof(struct tib), TIB_EXTRA_ALIGN) + extra) != 0)
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return NULL;
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thread = (char *)base + _static_tls_align_offset + _static_tls_size +
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ELF_ROUND(sizeof(struct tib), TIB_EXTRA_ALIGN);
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# endif
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return _static_tls_init(base, thread);
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#endif /* !PIC */
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}
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void
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_dl_free_tib(void *tib, size_t extra)
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{
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#ifndef PIC
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size_t tib_offset;
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# if TLS_VARIANT == 1
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tib_offset = (extra <= _static_tls_align_offset) ? 0 :
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ELF_ROUND(extra - _static_tls_align_offset, _static_tls_align);
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# elif TLS_VARIANT == 2
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tib_offset = _static_tls_size;
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# endif
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tib_offset += _static_tls_align_offset;
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free((char *)tib - tib_offset);
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#endif /* !PIC */
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}
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