1  /* Thread-local storage handling in the ELF dynamic linker.  x86-64 version.
       2     Copyright (C) 2017-2023 Free Software Foundation, Inc.
       3     This file is part of the GNU C Library.
       4  
       5     The GNU C Library is free software; you can redistribute it and/or
       6     modify it under the terms of the GNU Lesser General Public
       7     License as published by the Free Software Foundation; either
       8     version 2.1 of the License, or (at your option) any later version.
       9  
      10     The GNU C Library is distributed in the hope that it will be useful,
      11     but WITHOUT ANY WARRANTY; without even the implied warranty of
      12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      13     Lesser General Public License for more details.
      14  
      15     You should have received a copy of the GNU Lesser General Public
      16     License along with the GNU C Library; if not, see
      17     <https://www.gnu.org/licenses/>.  */
      18  
      19  #ifdef SHARED
      20  /* Work around GCC PR58066, due to which __tls_get_addr may be called
      21     with an unaligned stack.  The compat implementation is in
      22     tls_get_addr-compat.S.  */
      23  
      24  # include <dl-tls.h>
      25  
      26  /* Define __tls_get_addr within elf/dl-tls.c under a different
      27     name.  */
      28  extern __typeof__ (__tls_get_addr) ___tls_get_addr;
      29  
      30  # define __tls_get_addr ___tls_get_addr
      31  # include <elf/dl-tls.c>
      32  # undef __tls_get_addr
      33  
      34  hidden_ver (___tls_get_addr, __tls_get_addr)
      35  
      36  /* Only handle slow paths for __tls_get_addr.  */
      37  attribute_hidden
      38  void *
      39  __tls_get_addr_slow (GET_ADDR_ARGS)
      40  {
      41    dtv_t *dtv = THREAD_DTV ();
      42  
      43    size_t gen = atomic_load_relaxed (&GL(dl_tls_generation));
      44    if (__glibc_unlikely (dtv[0].counter != gen))
      45      return update_get_addr (GET_ADDR_PARAM);
      46  
      47    return tls_get_addr_tail (GET_ADDR_PARAM, dtv, NULL);
      48  }
      49  #else
      50  
      51  /* No compatibility symbol needed.  */
      52  # include <elf/dl-tls.c>
      53  
      54  #endif