sysdeps/s390/dl-tls.h

   1 /* Thread-local storage handling in the ELF dynamic linker.  s390 version.
   2    Copyright (C) 2003-2013 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
  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) attribute_hidden;
  31 extern unsigned long __tls_get_offset (unsigned long got_offset);
  32
  33 # ifdef IS_IN_rtld
  34 /* The special thing about the s390 TLS ABI is that we do not have the
  35    standard __tls_get_addr function but the __tls_get_offset function
  36    which differs in two important aspects:
  37    1) __tls_get_offset gets a got offset instead of a pointer to the
  38       tls_index structure
  39    2) __tls_get_offset returns the offset of the requested variable to
  40       the thread descriptor instead of a pointer to the variable.
  41  */
  42 #  ifdef __s390x__
  43 asm("\n\
  44         .text\n\
  45         .globl __tls_get_offset\n\
  46         .type __tls_get_offset, @function\n\
  47         .align 4\n\
  48 __tls_get_offset:\n\
  49         la      %r2,0(%r2,%r12)\n\
  50         jg      __tls_get_addr\n\
  51 ");
  52 #  elif defined __s390__
  53 asm("\n\
  54         .text\n\
  55         .globl __tls_get_offset\n\
  56         .type __tls_get_offset, @function\n\
  57         .align 4\n\
  58 __tls_get_offset:\n\
  59         basr    %r3,0\n\
  60 0:      la      %r2,0(%r2,%r12)\n\
  61         l       %r4,1f-0b(%r3)\n\
  62         b       0(%r4,%r3)\n\
  63 1:      .long   __tls_get_addr - 0b\n\
  64 ");
  65 #  endif
  66 # endif
  67
  68 # define GET_ADDR_OFFSET \
  69   (ti->ti_offset - (unsigned long) __builtin_thread_pointer ())
  70
  71 # define __TLS_GET_ADDR(__ti) \
  72   ({ extern char _GLOBAL_OFFSET_TABLE_[] attribute_hidden;                \
  73      (void *) __tls_get_offset ((char *) (__ti) - _GLOBAL_OFFSET_TABLE_)  \
  74      + (unsigned long) __builtin_thread_pointer (); })
  75
  76 #endif
  77
  78 /* Value used for dtv entries for which the allocation is delayed.  */
  79 #define TLS_DTV_UNALLOCATED     ((void *) -1l)