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031e519c95
This change forces realignment of the stack pointer in __tls_get_addr, so that binaries compiled by GCCs older than GCC 4.9: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58066 continue to work even if vector instructions are used in glibc which require the ABI stack realignment. __tls_get_addr_slow is added to handle the slow paths in the default implementation of__tls_get_addr in elf/dl-tls.c. The new __tls_get_addr calls __tls_get_addr_slow after realigning the stack. Internal calls within ld.so go directly to the default implementation of __tls_get_addr because they do not need stack realignment. [BZ #21609] * sysdeps/x86_64/Makefile (sysdep-dl-routines): Add tls_get_addr. (gen-as-const-headers): Add rtld-offsets.sym. * sysdeps/x86_64/dl-tls.c: New file. * sysdeps/x86_64/rtld-offsets.sym: Likwise. * sysdeps/x86_64/tls_get_addr.S: Likewise. * sysdeps/x86_64/dl-tls.h: Add multiple inclusion guards. * sysdeps/x86_64/tlsdesc.sym (TI_MODULE_OFFSET): New. (TI_OFFSET_OFFSET): Likwise.
54 lines
1.7 KiB
C
54 lines
1.7 KiB
C
/* Thread-local storage handling in the ELF dynamic linker. x86-64 version.
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Copyright (C) 2017 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#ifdef SHARED
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/* Work around GCC PR58066, due to which __tls_get_addr may be called
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with an unaligned stack. The compat implementation is in
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tls_get_addr-compat.S. */
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# include <dl-tls.h>
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/* Define __tls_get_addr within elf/dl-tls.c under a different
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name. */
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extern __typeof__ (__tls_get_addr) ___tls_get_addr;
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# define __tls_get_addr ___tls_get_addr
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# include <elf/dl-tls.c>
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# undef __tls_get_addr
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hidden_ver (___tls_get_addr, __tls_get_addr)
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/* Only handle slow paths for __tls_get_addr. */
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attribute_hidden
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void *
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__tls_get_addr_slow (GET_ADDR_ARGS)
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{
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dtv_t *dtv = THREAD_DTV ();
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if (__glibc_unlikely (dtv[0].counter != GL(dl_tls_generation)))
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return update_get_addr (GET_ADDR_PARAM);
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return tls_get_addr_tail (GET_ADDR_PARAM, dtv, NULL);
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}
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#else
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/* No compatibility symbol needed. */
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# include <elf/dl-tls.c>
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#endif
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