sysdeps/hppa/elf/initfini.c

   1 /* Special .init and .fini section support for HPPA
   2    Copyright (C) 2000, 2002 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    In addition to the permissions in the GNU Lesser General Public
  11    License, the Free Software Foundation gives you unlimited
  12    permission to link the compiled version of this file with other
  13    programs, and to distribute those programs without any restriction
  14    coming from the use of this file. (The GNU Lesser General Public
  15    License restrictions do apply in other respects; for example, they
  16    cover modification of the file, and distribution when not linked
  17    into another program.)
  18
  19    Note that people who make modified versions of this file are not
  20    obligated to grant this special exception for their modified
  21    versions; it is their choice whether to do so. The GNU Lesser
  22    General Public License gives permission to release a modified
  23    version without this exception; this exception also makes it
  24    possible to release a modified version which carries forward this
  25    exception.
  26
  27    The GNU C Library is distributed in the hope that it will be useful,
  28    but WITHOUT ANY WARRANTY; without even the implied warranty of
  29    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  30    Lesser General Public License for more details.
  31
  32    You should have received a copy of the GNU Lesser General Public
  33    License along with the GNU C Library; if not, write to the Free
  34    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  35    02111-1307 USA.  */
  36
  37 /* This file is compiled into assembly code which is then munged by a sed
  38    script into two files: crti.s and crtn.s.
  39
  40    * crti.s puts a function prologue at the beginning of the
  41    .init and .fini sections and defines global symbols for
  42    those addresses, so they can be called as functions.
  43
  44    * crtn.s puts the corresponding function epilogues
  45    in the .init and .fini sections. */
  46
  47 /* If we use the standard C version, the linkage table pointer won't
  48    be properly preserved due to the splitting up of function prologues
  49    and epilogues.  Therefore we write these in assembly to make sure
  50    they do the right thing.
  51
  52    Note that we cannot have a weak undefined __gmon_start__, because
  53    that would require this to be PIC, and the linker is currently not
  54    able to generate a proper procedure descriptor for _init.  Sad but
  55    true.  Anyway, HPPA is one of those horrible architectures where
  56    making the comparison and indirect call is quite expensive (see the
  57    comment in sysdeps/generic/initfini.c). */
  58
  59 __asm__ ("\
  60 \n\
  61 #include \"defs.h\"\n\
  62 \n\
  63 /*@HEADER_ENDS*/\n\
  64 \n\
  65 /*@_init_PROLOG_BEGINS*/\n\
  66         .section .init\n\
  67         .align 4\n\
  68         .globl _init\n\
  69         .type _init,@function\n\
  70 _init:\n\
  71         stw     %rp,-20(%sp)\n\
  72         stwm    %r4,64(%sp)\n\
  73         stw     %r19,-32(%sp)\n\
  74         bl      __gmon_start__,%rp\n\
  75         copy    %r19,%r4        /* delay slot */\n\
  76         copy    %r4,%r19\n\
  77 /*@_init_PROLOG_ENDS*/\n\
  78 \n\
  79 /*@_init_EPILOG_BEGINS*/\n\
  80         .text\n\
  81         .align 4\n\
  82         .weak   __gmon_start__\n\
  83         .type    __gmon_start__,@function\n\
  84 __gmon_start__:\n\
  85         .proc\n\
  86         .callinfo\n\
  87         .entry\n\
  88         bv,n %r0(%r2)\n\
  89         .exit\n\
  90         .procend\n\
  91 \n\
  92 /* Here is the tail end of _init.  We put __gmon_start before this so\n\
  93    that the assembler creates the .PARISC.unwind section for us, ie.\n\
  94    with the right attributes.  */\n\
  95         .section .init\n\
  96         ldw     -84(%sp),%rp\n\
  97         copy    %r4,%r19\n\
  98         bv      %r0(%rp)\n\
  99 _end_init:\n\
 100         ldwm    -64(%sp),%r4\n\
 101 \n\
 102 /* Our very own unwind info, because the assembler can't handle\n\
 103    functions split into two or more pieces.  */\n\
 104         .section .PARISC.unwind\n\
 105         .extern _init\n\
 106         .word   _init, _end_init\n\
 107         .byte   0x08, 0x01, 0x00, 0x08, 0x00, 0x00, 0x00, 0x08\n\
 108 \n\
 109 /*@_init_EPILOG_ENDS*/\n\
 110 \n\
 111 /*@_fini_PROLOG_BEGINS*/\n\
 112         .section .fini\n\
 113         .align 4\n\
 114         .globl _fini\n\
 115         .type _fini,@function\n\
 116 _fini:\n\
 117         stw     %rp,-20(%sp)\n\
 118         stwm    %r4,64(%sp)\n\
 119         stw     %r19,-32(%sp)\n\
 120         copy    %r19,%r4\n\
 121 /*@_fini_PROLOG_ENDS*/\n\
 122 \n\
 123 /*@_fini_EPILOG_BEGINS*/\n\
 124         .section .fini\n\
 125         ldw     -84(%sp),%rp\n\
 126         copy    %r4,%r19\n\
 127         bv      %r0(%rp)\n\
 128 _end_fini:\n\
 129         ldwm    -64(%sp),%r4\n\
 130 \n\
 131         .section .PARISC.unwind\n\
 132         .extern _fini\n\
 133         .word   _fini, _end_fini\n\
 134         .byte   0x08, 0x01, 0x00, 0x08, 0x00, 0x00, 0x00, 0x08\n\
 135 \n\
 136 /*@_fini_EPILOG_ENDS*/\n\
 137 \n\
 138 /*@TRAILER_BEGINS*/\
 139 ");