From 031e519c95c069abe4e4c7c59e2b4b67efccdee5 Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Thu, 6 Jul 2017 04:43:06 -0700 Subject: x86-64: Align the stack in __tls_get_addr [BZ #21609] 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. --- sysdeps/x86_64/dl-tls.c | 53 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 53 insertions(+) create mode 100644 sysdeps/x86_64/dl-tls.c (limited to 'sysdeps/x86_64/dl-tls.c') diff --git a/sysdeps/x86_64/dl-tls.c b/sysdeps/x86_64/dl-tls.c new file mode 100644 index 0000000000..3584805c8e --- /dev/null +++ b/sysdeps/x86_64/dl-tls.c @@ -0,0 +1,53 @@ +/* Thread-local storage handling in the ELF dynamic linker. x86-64 version. + Copyright (C) 2017 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#ifdef SHARED +/* Work around GCC PR58066, due to which __tls_get_addr may be called + with an unaligned stack. The compat implementation is in + tls_get_addr-compat.S. */ + +# include + +/* Define __tls_get_addr within elf/dl-tls.c under a different + name. */ +extern __typeof__ (__tls_get_addr) ___tls_get_addr; + +# define __tls_get_addr ___tls_get_addr +# include +# undef __tls_get_addr + +hidden_ver (___tls_get_addr, __tls_get_addr) + +/* Only handle slow paths for __tls_get_addr. */ +attribute_hidden +void * +__tls_get_addr_slow (GET_ADDR_ARGS) +{ + dtv_t *dtv = THREAD_DTV (); + + if (__glibc_unlikely (dtv[0].counter != GL(dl_tls_generation))) + return update_get_addr (GET_ADDR_PARAM); + + return tls_get_addr_tail (GET_ADDR_PARAM, dtv, NULL); +} +#else + +/* No compatibility symbol needed. */ +# include + +#endif -- cgit v1.2.3