sysdeps/x86_64/x32/dl-machine.h

   1 /* Machine-dependent ELF dynamic relocation inline functions.  x32 version.
   2    Copyright (C) 2012-2014 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 /* Must allow <sysdeps/x86_64/dl-machine.h> to be included more than once.
  20    See #ifdef RESOLVE_MAP in sysdeps/x86_64/dl-machine.h.  */
  21 #include <sysdeps/x86_64/dl-machine.h>
  22
  23 #ifndef _X32_DL_MACHINE_H
  24 #define _X32_DL_MACHINE_H
  25
  26 #undef ARCH_LA_PLTENTER
  27 #undef ARCH_LA_PLTEXIT
  28 #undef RTLD_START
  29
  30 /* Names of the architecture-specific auditing callback functions.  */
  31 #define ARCH_LA_PLTENTER x32_gnu_pltenter
  32 #define ARCH_LA_PLTEXIT x32_gnu_pltexit
  33
  34 /* Initial entry point code for the dynamic linker.
  35    The C function `_dl_start' is the real entry point;
  36    its return value is the user program's entry point.  */
  37 #define RTLD_START asm ("\n\
  38 .text\n\
  39         .p2align 4\n\
  40 .globl _start\n\
  41 .globl _dl_start_user\n\
  42 _start:\n\
  43         movl %esp, %edi\n\
  44         call _dl_start\n\
  45 _dl_start_user:\n\
  46         # Save the user entry point address in %r12.\n\
  47         movl %eax, %r12d\n\
  48         # See if we were run as a command with the executable file\n\
  49         # name as an extra leading argument.\n\
  50         movl _dl_skip_args(%rip), %eax\n\
  51         # Pop the original argument count.\n\
  52         movl (%rsp), %edx\n\
  53         # Adjust the stack pointer to skip _dl_skip_args words.\n\
  54         lea 4(%rsp,%rax,4), %esp\n\
  55         # Subtract _dl_skip_args from argc.\n\
  56         subl %eax, %edx\n\
  57         # Push argc back on the stack.\n\
  58         subl $4, %esp\n\
  59         movl %edx, (%rsp)\n\
  60         # Call _dl_init (struct link_map *main_map, int argc, char **argv, char **env)\n\
  61         # argc -> rsi\n\
  62         movl %edx, %esi\n\
  63         # Save %rsp value in %r13.\n\
  64         movl %esp, %r13d\n\
  65         # And align stack for the _dl_init call.\n\
  66         and $-16, %esp\n\
  67         # _dl_loaded -> rdi\n\
  68         movl _rtld_local(%rip), %edi\n\
  69         # env -> rcx\n\
  70         lea 8(%r13,%rdx,4), %ecx\n\
  71         # argv -> rdx\n\
  72         lea 4(%r13), %edx\n\
  73         # Clear %rbp to mark outermost frame obviously even for constructors.\n\
  74         xorl %ebp, %ebp\n\
  75         # Call the function to run the initializers.\n\
  76         call _dl_init\n\
  77         # Pass our finalizer function to the user in %rdx, as per ELF ABI.\n\
  78         lea _dl_fini(%rip), %edx\n\
  79         # And make sure %rsp points to argc stored on the stack.\n\
  80         movl %r13d, %esp\n\
  81         # Jump to the user's entry point.\n\
  82         jmp *%r12\n\
  83 .previous\n\
  84 ");
  85
  86 #endif /* !_X32_DL_MACHINE_H */