nptl/sysdeps/unix/sysv/linux/i386/dl-sysdep.h

   1 /* System-specific settings for dynamic linker code.  IA-32 version.
   2    Copyright (C) 2002, 2003, 2008 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, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #ifndef _DL_SYSDEP_H
  21 #define _DL_SYSDEP_H    1
  22
  23 /* This macro must be defined to either 0 or 1.
  24
  25    If 1, then an errno global variable hidden in ld.so will work right with
  26    all the errno-using libc code compiled for ld.so, and there is never a
  27    need to share the errno location with libc.  This is appropriate only if
  28    all the libc functions that ld.so uses are called without PLT and always
  29    get the versions linked into ld.so rather than the libc ones.  */
  30
  31 #ifdef IS_IN_rtld
  32 # define RTLD_PRIVATE_ERRNO 1
  33 #else
  34 # define RTLD_PRIVATE_ERRNO 0
  35 #endif
  36
  37 /* Traditionally system calls have been made using int $0x80.  A
  38    second method was introduced which, if possible, will use the
  39    sysenter/syscall instructions.  To signal the presence and where to
  40    find the code the kernel passes an AT_SYSINFO value in the
  41    auxiliary vector to the application.
  42    sysenter/syscall is not useful on i386 through i586, but the dynamic
  43    linker and dl code in libc.a has to be able to load i686 compiled
  44    libraries.  */
  45 #define NEED_DL_SYSINFO 1
  46 #undef USE_DL_SYSINFO
  47
  48 #if defined NEED_DL_SYSINFO && !defined __ASSEMBLER__
  49 extern void _dl_sysinfo_int80 (void) attribute_hidden;
  50 # define DL_SYSINFO_DEFAULT (uintptr_t) _dl_sysinfo_int80
  51 # define DL_SYSINFO_IMPLEMENTATION \
  52   asm (".text\n\t"                                                            \
  53        ".type _dl_sysinfo_int80,@function\n\t"                                \
  54        ".hidden _dl_sysinfo_int80\n\t"                                        \
  55        CFI_STARTPROC "\n"                                                     \
  56        "_dl_sysinfo_int80:\n\t"                                               \
  57        "int $0x80;\n\t"                                                       \
  58        "ret;\n\t"                                                             \
  59        CFI_ENDPROC "\n"                                                       \
  60        ".size _dl_sysinfo_int80,.-_dl_sysinfo_int80\n\t"                      \
  61        ".previous;");
  62 #endif
  63
  64
  65 /* The _dl_discover_osversion function is so far only needed in sysconf
  66    to check for kernels later than 2.6.23.  */
  67 #if !defined __ASSEMBLER__ && __LINUX_KERNEL_VERSION < 0x020617
  68 /* Get version of the OS.  */
  69 extern int _dl_discover_osversion (void) attribute_hidden;
  70 # define HAVE_DL_DISCOVER_OSVERSION     1
  71 #endif
  72
  73 #endif  /* dl-sysdep.h */