glibc/sysdeps/x86_64/dl-tls.c

/* 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
   <http://www.gnu.org/licenses/>.  */

#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 <dl-tls.h>

/* 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 <elf/dl-tls.c>
# 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 <elf/dl-tls.c>

#endif