sysdeps/i386/dl-tls.h

   1 /* Thread-local storage handling in the ELF dynamic linker.  i386 version.
   2    Copyright (C) 2002-2017 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    <http://www.gnu.org/licenses/>.  */
  18
  19
  20 /* Type used for the representation of TLS information in the GOT.  */
  21 typedef struct dl_tls_index
  22 {
  23   unsigned long int ti_module;
  24   unsigned long int ti_offset;
  25 } tls_index;
  26
  27
  28 #ifdef SHARED
  29 /* This is the prototype for the GNU version.  */
  30 extern void *___tls_get_addr (tls_index *ti)
  31      __attribute__ ((__regparm__ (1)));
  32 extern void *___tls_get_addr_internal (tls_index *ti)
  33      __attribute__ ((__regparm__ (1))) attribute_hidden;
  34
  35 # if IS_IN (rtld)
  36 /* The special thing about the x86 TLS ABI is that we have two
  37    variants of the __tls_get_addr function with different calling
  38    conventions.  The GNU version, which we are mostly concerned here,
  39    takes the parameter in a register.  The name is changed by adding
  40    an additional underscore at the beginning.  The Sun version uses
  41    the normal calling convention.  */
  42 void *
  43 __tls_get_addr (tls_index *ti)
  44 {
  45   return ___tls_get_addr_internal (ti);
  46 }
  47
  48
  49 /* Prepare using the definition of __tls_get_addr in the generic
  50    version of this file.  */
  51 # define __tls_get_addr __attribute__ ((__regparm__ (1))) ___tls_get_addr
  52 strong_alias (___tls_get_addr, ___tls_get_addr_internal)
  53 rtld_hidden_proto (___tls_get_addr)
  54 rtld_hidden_def (___tls_get_addr)
  55 #else
  56
  57 /* Users should get the better interface.  */
  58 # define __tls_get_addr ___tls_get_addr
  59
  60 # endif
  61 #endif