/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 *      Copyright (c) 1988 AT&T
 *        All Rights Reserved
 *
 *
 * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*
 * Bootstrap routine for run-time linker.
 * We get control from exec which has loaded our text and
 * data into the process' address space and created the process
 * stack.
 *
 * On entry, the process stack looks like this:
 *
 *      #                       # <- %esp
 *      #_______________________#  high addresses
 *      #       strings         #
 *      #_______________________#
 *      #       0 word          #
 *      #_______________________#
 *      #       Auxiliary       #
 *      #       entries         #
 *      #       ...             #
 *      #       (size varies)   #
 *      #_______________________#
 *      #       0 word          #
 *      #_______________________#
 *      #       Environment     #
 *      #       pointers        #
 *      #       ...             #
 *      #       (one word each) #
 *      #_______________________#
 *      #       0 word          #
 *      #_______________________#
 *      #       Argument        # low addresses
 *      #       pointers        #
 *      #       Argc words      #
 *      #_______________________#
 *      #       argc            #
 *      #_______________________# <- %ebp
 *
 *
 * We must calculate the address at which ld.so was loaded,
 * find the addr of the dynamic section of ld.so, of argv[0], and  of
 * the process' environment pointers - and pass the thing to _setup
 * to handle.  We then call _rtld - on return we jump to the entry
 * point for the executable.
 */

#if     defined(lint)

extern  unsigned long   _setup();
extern  void            atexit_fini();
void
main()
{
        (void) _setup();
        atexit_fini();
}

#else

#include        <link.h>

        .file   "boot.s"
        .text
        .globl  _rt_boot
        .globl  _setup
        .globl  _GLOBAL_OFFSET_TABLE_
        .type   _rt_boot,@function
        .align  4

        / init is called from the _init symbol in the CRT, however .init_array
        / are called "naturally" from call_init.  Because of that, we need the
        / stack aligned here so that initializers called via _array sections may
        / safely use SIMD instructions.
_rt_alias:
        jmp     .get_ip                 / in case we were invoked from libc.so
_rt_boot:
        movl    %esp,%ebp               / save for referencing args
        subl    $EB_MAX_SIZE32,%esp     / make room for a max sized boot vector
        andl    $-16,%esp
        subl    $8,%esp
        movl    %esp,%esi               / use esi as a pointer to &eb[0]
        movl    $EB_ARGV,0(%esi)        / set up tag for argv
        leal    4(%ebp),%eax            / get address of argv
        movl    %eax,4(%esi)            / put after tag
        movl    $EB_ENVP,8(%esi)        / set up tag for envp
        movl    (%ebp),%eax             / get # of args
        addl    $2,%eax                 / one for the zero & one for argc
        leal    (%ebp,%eax,4),%edi      / now points past args & @ envp
        movl    %edi,12(%esi)           / set envp
.L0:    addl    $4,%edi                 / next
        cmpl    $0,-4(%edi)             / search for 0 at end of env
        jne     .L0
        movl    $EB_AUXV,16(%esi)       / set up tag for auxv
        movl    %edi,20(%esi)           / point to auxv
        movl    $EB_NULL,24(%esi)       / set up NULL tag
.get_ip:
        call    .L1                     / only way to get IP into a register
.L1:
        popl    %ebx                    / pop the IP we just "pushed"
        addl    $_GLOBAL_OFFSET_TABLE_+[.-.L1],%ebx
        pushl   (%ebx)                  / address of dynamic structure
        pushl   %esi                    / push &eb[0]

        call    _setup@PLT              / _setup(&eb[0], _DYNAMIC)
        movl    %ebp,%esp               / release stack frame

        movl    atexit_fini@GOT(%ebx), %edx
        jmp     *%eax                   / transfer control to the executable
        .size   _rt_boot,.-_rt_boot

#endif