minix/lib/csu/mips/crt0.c

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/* $NetBSD: crt0.c,v 1.22 2011/02/22 05:45:07 joerg Exp $ */
/*
* Copyright (c) 1995 Christopher G. Demetriou
* All rights reserved.
*
* Modifications for NetBSD/mips:
*
* Jonathan Stone
* Jason R. Thorpe, Numerical Aerospace Simulation Facility,
* NASA Ames Research Center
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Christopher G. Demetriou
* for the NetBSD Project.
* 4. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "common.h"
/*
* C start-up. Assumes kernel (or ld.so) passes the
* following parameters to user-space in registers:
*
* a0 stack pointer (0 if setregs didn't fill this in)
* a1 cleanup
* a2 Obj_Entry
* a3 ps_strings
*
* XXX Does this violate the ABI?
* as well as the usual registers (pc, sp, and t9 == pc for ABI).
*/
void __start(uintptr_t, void (*)(void), const Obj_Entry *,
struct ps_strings *);
__asm(".text; .align 4; .globl _start; _start:");
void
__start(uintptr_t sp,
void (*cleanup)(void), /* from shared loader */
const Obj_Entry *obj, /* from shared loader */
struct ps_strings *ps_strings)
{
char **ksp;
char **argv, *namep;
int argc;
/*
* Grab the argc, argv, and envp set up by the kernel.
* Layout of stuff on the stack:
*
* [ high ]
* char kenvstr[1]; // size varies
* char kargstr[1]; // size varies
* char *argv[1]; // varies on argc
* int argc;
* [ low ] <--- kernel's SP points here
* .
* .
* .
* [ current stack pointer ]
*
* WARNING! There is an implicit sizeof(int) == sizeof(char *) here!
*/
#ifndef DYNAMIC
#ifdef _LP64
__asm volatile("dla $28,_gp");
#else
__asm volatile("la $28,_gp");
#endif
#endif
ksp = (char**)sp;
#if defined(__mips_n32) || defined(__mips_n64)
if (ksp == 0) {
/*
* Uh, oh. We're running on a old kernel that passed
* us zero in $a0-$a3. Try adjusting the current
* $sp for our own stack-frame size and see what
* we find.
* WARNING! The constants 56 and 64 below were determined
* by examining GCC assembler output of __start to find the
* frame size. If you change the code or compiler,
* you _will_ lose!
*/
#ifndef DYNAMIC
/* XXX 56 is compiler and stackframe dependent */
__asm volatile(" addiu %0,$29,56" : "=r" (ksp));
#else
/* XXX 64 is compiler and stackframe dependent */
__asm volatile(" addiu %0,$29,64" : "=r" (ksp));
#endif
}
#endif
argc = *(long *)ksp;
argv = ksp + 1;
environ = ksp + 2 + argc; /* 2: argc + NULL ending argv */
if ((namep = argv[0]) != NULL) { /* NULL ptr if argc = 0 */
if ((__progname = _strrchr(namep, '/')) == NULL)
__progname = namep;
else
__progname++;
}
/*
* Deal with stuff that is only provided if setregs() did
* did the right thing.
*/
if (sp != 0) {
if (ps_strings != (struct ps_strings *)0)
__ps_strings = ps_strings;
#ifdef DYNAMIC
/*
* XXX Old MIPS ld.so didn't do any of this at all.
* XXX If we were loaded by that loader, just abort
* XXX the rtld setup.
*/
if (&rtld_DYNAMIC != NULL && cleanup != NULL && obj != NULL)
_rtld_setup(cleanup, obj);
#endif
}
#ifdef MCRT0
atexit(_mcleanup);
monstartup((uintptr_t)&_eprol, (uintptr_t)&_etext);
#endif
atexit(_fini);
_init();
exit(main(argc, argv, environ));
}
/*
* RCSid. Place after __start for programs that assume start of text
* is the entrypoint. (Only needed for old toolchains).
*/
#if defined(LIBC_SCCS) && !defined(lint)
__RCSID("$NetBSD: crt0.c,v 1.22 2011/02/22 05:45:07 joerg Exp $");
#endif /* LIBC_SCCS and not lint */
#include "common.c"