libgcc/config/aarch64/crtn.S

   1 # Machine description for AArch64 architecture.
   2 # Copyright (C) 2009-2021 Free Software Foundation, Inc.
   3 # Contributed by ARM Ltd.
   4 #
   5 # This file is free software; you can redistribute it and/or modify it
   6 # under the terms of the GNU General Public License as published by the
   7 # Free Software Foundation; either version 3, or (at your option) any
   8 # later version.
   9 #
  10 # This file is distributed in the hope that it will be useful, but
  11 # WITHOUT ANY WARRANTY; without even the implied warranty of
  12 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13 # General Public License for more details.
  14 #
  15 # Under Section 7 of GPL version 3, you are granted additional
  16 # permissions described in the GCC Runtime Library Exception, version
  17 # 3.1, as published by the Free Software Foundation.
  18 #
  19 # You should have received a copy of the GNU General Public License and
  20 # a copy of the GCC Runtime Library Exception along with this program;
  21 # see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  22 # <http://www.gnu.org/licenses/>.
  23
  24 /* An executable stack is *not* required for these functions.  */
  25 #if defined(__ELF__) && defined(__linux__)
  26 .section .note.GNU-stack,"",%progbits
  27 .previous
  28 #endif
  29
  30 # This file just makes sure that the .fini and .init sections do in
  31 # fact return.  Users may put any desired instructions in those sections.
  32 # This file is the last thing linked into any executable.
  33
  34         # Note - this macro is complemented by the FUNC_START macro
  35         # in crti.S.  If you change this macro you must also change
  36         # that macro match.
  37         #
  38         # Note - we do not try any fancy optimizations of the return
  39         # sequences here, it is just not worth it.  Instead keep things
  40         # simple.  Restore all the save resgisters, including the link
  41         # register and then perform the correct function return instruction.
  42 .macro FUNC_END
  43         ldp     x19, x20, [sp], #16
  44         ldp     x21, x22, [sp], #16
  45         ldp     x23, x24, [sp], #16
  46         ldp     x25, x26, [sp], #16
  47         ldp     x27, x28, [sp], #16
  48         ldp     x29, x30, [sp], #16
  49         ret
  50 .endm
  51
  52
  53         .section        ".init"
  54         ;;
  55         FUNC_END
  56
  57         .section        ".fini"
  58         ;;
  59         FUNC_END
  60
  61 # end of crtn.S