159 lines
5.3 KiB
C
159 lines
5.3 KiB
C
/* $NetBSD: crt0.c,v 1.4 2003/10/06 05:28:05 matt Exp $ */
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/*
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* Copyright (c) 2002 Matt Fredette
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* Copyright (c) 1999 Klaus Klein
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* Copyright (c) 1995 Christopher G. Demetriou
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed for the
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* NetBSD Project. See http://www.NetBSD.org/ for
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* information about NetBSD.
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* 4. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* <<Id: LICENSE,v 1.2 2000/06/14 15:57:33 cgd Exp>>
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*/
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#include "common.h"
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int __global __asm ("$global$") = 0;
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static void ___start __P((struct ps_strings *,
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void (*cleanup) __P((void)), const Obj_Entry *, int))
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#ifdef __GNUC__
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__attribute__((__unused__))
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#endif
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;
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__asm("\n"
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" .text \n"
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" .align 4 \n"
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" .globl _start \n"
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" .globl _start \n"
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" .type __start,@function \n"
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" .type __start,@function \n"
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"_start: \n"
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"__start: \n"
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" .import $global$, data \n"
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" ldil L%$global$, %r27 \n"
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" ldo R%$global$(%r27), %r27 \n"
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" copy %r27, %r19 \n"
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" b ___start \n"
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" copy %r27, %arg3 \n");
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static void
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___start(ps_strings, cleanup, obj, dp)
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struct ps_strings *ps_strings;
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void (*cleanup) __P((void)); /* from shared loader */
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const Obj_Entry *obj; /* from shared loader */
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int dp;
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{
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int argc;
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char **argv;
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int fini_plabel[2];
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argc = ps_strings->ps_nargvstr;
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argv = ps_strings->ps_argvstr;
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environ = ps_strings->ps_envstr;
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if ((__progname = argv[0]) != NULL) { /* NULL ptr if argc = 0 */
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if ((__progname = _strrchr(__progname, '/')) == NULL)
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__progname = argv[0];
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else
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__progname++;
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}
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if (ps_strings != (struct ps_strings *)0)
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__ps_strings = ps_strings;
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#ifdef DYNAMIC
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/*
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* XXX fredette - when not compiling PIC, you currently
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* can't detect an undefined weak symbol by seeing if
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* its address is NULL. The compiler emits code to find
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* _DYNAMIC relative to %dp, the assembler notes the
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* needed relocations, but when the linker sees that the
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* (weak) symbol isn't defined it drops the ball - the
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* relocations are never filled, and the binary ends up
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* with code that sees an address of %dp plus zero,
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* which != NULL.
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*
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* Arguably the linker could/should distinguish between
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* code that is after a weak undefined symbol's contents
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* from code that is after its address. In the first case,
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* it would warn and/or bail. In the second case, it
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* would fix up instructions to give a symbol address
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* of NULL.
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*
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* For now, we take the easy way out and compare &_DYNAMIC
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* to %dp, as well as to NULL.
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*/
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if (&_DYNAMIC != NULL && (int)&_DYNAMIC != dp)
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_rtld_setup(cleanup, obj);
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#endif
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#ifdef MCRT0
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atexit(_mcleanup);
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monstartup((u_long)&_eprol, (u_long)&_etext);
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#endif
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/*
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* Since crt0.o, crtbegin.o, and crtend.o are always
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* compiled PIC, they must have %r19 set correctly on
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* entry to any function they contain. However, when
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* a program is linked statically, the linker does
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* not fill a PLABEL relocation with a pointer to a
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* true PLABEL, it just fills it with the offset of the
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* function. This shows the linker's assumption that
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* when linking statically, *all* of the code has *not*
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* been compiled PIC. I guess to assume otherwise
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* would be a performance hit, as you would end up
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* with unnecessary PLABELs for function pointers.
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*
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* But here, passing the address of the PIC _fini to
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* atexit, we must make sure that we pass a PLABEL.
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*/
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fini_plabel[0] = (int)_fini;
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if (fini_plabel[0] & 2)
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/* _fini is already a PLABEL. */
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atexit(_fini);
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else {
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fini_plabel[1] = dp;
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atexit((void (*)(void))(((int)fini_plabel) | 2));
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}
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_init();
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exit(main(argc, argv, environ));
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}
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/*
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* NOTE: Leave the RCS ID _after_ __start(), in case it gets placed in .text.
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*/
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#if defined(LIBC_SCCS) && !defined(lint)
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__RCSID("$NetBSD: crt0.c,v 1.4 2003/10/06 05:28:05 matt Exp $");
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#endif /* LIBC_SCCS and not lint */
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#include "common.c"
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