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/* $OpenBSD: tib.c,v 1.1 2016/05/07 19:05:22 guenther 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> /* malloc 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; /* overriden by ld.so */ |
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#else |
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char *base; |
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char *thread; |
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struct tib *tib; |
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# if TLS_VARIANT == 1 |
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/* round up the extra size to align the tib after it */ |
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extra = ELF_ROUND(extra, sizeof(void *)); |
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base = malloc(extra + sizeof(struct tib) + _static_tls_size); |
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tib = (struct tib *)(base + extra); |
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thread = base; |
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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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base = malloc(ELF_ROUND(sizeof(struct tib), TIB_EXTRA_ALIGN) + |
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extra + _static_tls_size); |
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tib = (struct tib *)(base + _static_tls_size); |
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thread = (char *)tib + ELF_ROUND(sizeof(struct tib), TIB_EXTRA_ALIGN); |
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# endif |
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_static_tls_init(base); |
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TIB_INIT(tib, NULL, thread); |
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return (tib); |
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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 = ELF_ROUND(extra, sizeof(void *)); |
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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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free((char *)tib - tib_offset); |
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#endif /* !PIC */ |
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} |