lib/csu/hppa/crt0.c

   1 /*      $NetBSD: crt0.c,v 1.7 2004/08/26 21:07:14 thorpej Exp $ */
   2
   3 /*
   4  * Copyright (c) 2002 Matt Fredette
   5  * Copyright (c) 1999 Klaus Klein
   6  * Copyright (c) 1995 Christopher G. Demetriou
   7  * All rights reserved.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in the
  16  *    documentation and/or other materials provided with the distribution.
  17  * 3. All advertising materials mentioning features or use of this software
  18  *    must display the following acknowledgement:
  19  *          This product includes software developed for the
  20  *          NetBSD Project.  See http://www.NetBSD.org/ for
  21  *          information about NetBSD.
  22  * 4. The name of the author may not be used to endorse or promote products
  23  *    derived from this software without specific prior written permission.
  24  *
  25  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  26  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  27  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  28  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  29  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  30  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  31  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  32  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  33  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  34  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  35  *
  36  * <<Id: LICENSE,v 1.2 2000/06/14 15:57:33 cgd Exp>>
  37  */
  38
  39 #include "common.h"
  40
  41 static void ___start(struct ps_strings *,
  42     void (*cleanup)(void), const Obj_Entry *, int)
  43 #ifdef __GNUC__
  44     __attribute__((__used__))
  45 #endif
  46     ;
  47
  48 __asm("\n"
  49 "       .text                           \n"
  50 "       .align  4                       \n"
  51 "       .globl  _start                  \n"
  52 "       .globl  __start                 \n"
  53 "       .type   _start,@function        \n"
  54 "       .type   __start,@function       \n"
  55 "_start:                                \n"
  56 "__start:                               \n"
  57 "       .import _GLOBAL_OFFSET_TABLE_   \n"
  58 "\n"
  59 "       bl      L$lpc, %r27             \n"
  60 "       depi    0, 31, 2, %r27          \n"
  61 "L$lpc: addil   L'_GLOBAL_OFFSET_TABLE_ - ($PIC_pcrel$0 - 8), %r27      \n"
  62 "       ldo     R'_GLOBAL_OFFSET_TABLE_ - ($PIC_pcrel$0 - 12)(%r1),%r27 \n"
  63 "       copy    %r27, %r19              \n"
  64 "       b       ___start                \n"
  65 "       copy    %r27, %arg3             \n");
  66
  67 static void
  68 ___start(struct ps_strings *ps_strings,
  69     void (*cleanup)(void),                      /* from shared loader */
  70     const Obj_Entry *obj,                       /* from shared loader */
  71     int dp)
  72 {
  73         int argc;
  74         char **argv;
  75         int fini_plabel[2];
  76
  77         argc = ps_strings->ps_nargvstr;
  78         argv = ps_strings->ps_argvstr;
  79         environ = ps_strings->ps_envstr;
  80
  81         if ((__progname = argv[0]) != NULL) {   /* NULL ptr if argc = 0 */
  82                 if ((__progname = _strrchr(__progname, '/')) == NULL)
  83                         __progname = argv[0];
  84                 else
  85                         __progname++;
  86         }
  87
  88         if (ps_strings != (struct ps_strings *)0)
  89                 __ps_strings = ps_strings;
  90
  91 #ifdef DYNAMIC
  92         /*
  93          * XXX fredette - when not compiling PIC, you currently
  94          * can't detect an undefined weak symbol by seeing if
  95          * its address is NULL.  The compiler emits code to find
  96          * _DYNAMIC relative to %dp, the assembler notes the
  97          * needed relocations, but when the linker sees that the
  98          * (weak) symbol isn't defined it drops the ball - the
  99          * relocations are never filled, and the binary ends up
 100          * with code that sees an address of %dp plus zero,
 101          * which != NULL.
 102          *
 103          * Arguably the linker could/should distinguish between
 104          * code that is after a weak undefined symbol's contents
 105          * from code that is after its address.  In the first case,
 106          * it would warn and/or bail.  In the second case, it
 107          * would fix up instructions to give a symbol address
 108          * of NULL.
 109          *
 110          * For now, we take the easy way out and compare &_DYNAMIC
 111          * to %dp, as well as to NULL.
 112          */
 113         if (&_DYNAMIC != NULL && (int)&_DYNAMIC != dp)
 114                 _rtld_setup(cleanup, obj);
 115 #endif
 116
 117 #ifdef MCRT0
 118         atexit(_mcleanup);
 119         monstartup((u_long)&_eprol, (u_long)&_etext);
 120 #endif
 121
 122         /*
 123          * Since crt0.o, crtbegin.o, and crtend.o are always
 124          * compiled PIC, they must have %r19 set correctly on
 125          * entry to any function they contain.  However, when
 126          * a program is linked statically, the linker does
 127          * not fill a PLABEL relocation with a pointer to a
 128          * true PLABEL, it just fills it with the offset of the
 129          * function.  This shows the linker's assumption that
 130          * when linking statically, *all* of the code has *not*
 131          * been compiled PIC.  I guess to assume otherwise
 132          * would be a performance hit, as you would end up
 133          * with unnecessary PLABELs for function pointers.
 134          *
 135          * But here, passing the address of the PIC _fini to
 136          * atexit, we must make sure that we pass a PLABEL.
 137          */
 138         fini_plabel[0] = (int)_fini;
 139         if (fini_plabel[0] & 2)
 140                 /* _fini is already a PLABEL. */
 141                 atexit(_fini);
 142         else {
 143                 fini_plabel[1] = dp;
 144                 atexit((void (*)(void))(((int)fini_plabel) | 2));
 145         }
 146         _init();
 147
 148         exit(main(argc, argv, environ));
 149 }
 150
 151 /*
 152  * NOTE: Leave the RCS ID _after_ __start(), in case it gets placed in .text.
 153  */
 154 #if defined(LIBC_SCCS) && !defined(lint)
 155 __RCSID("$NetBSD: crt0.c,v 1.7 2004/08/26 21:07:14 thorpej Exp $");
 156 #endif /* LIBC_SCCS and not lint */
 157
 158 #include "common.c"