xref: /onnv-gate/usr/src/cmd/sgs/rtld/i386/boot.s (revision 0:68f95e015346)
1*0Sstevel@tonic-gate/*
2*0Sstevel@tonic-gate * CDDL HEADER START
3*0Sstevel@tonic-gate *
4*0Sstevel@tonic-gate * The contents of this file are subject to the terms of the
5*0Sstevel@tonic-gate * Common Development and Distribution License, Version 1.0 only
6*0Sstevel@tonic-gate * (the "License").  You may not use this file except in compliance
7*0Sstevel@tonic-gate * with the License.
8*0Sstevel@tonic-gate *
9*0Sstevel@tonic-gate * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10*0Sstevel@tonic-gate * or http://www.opensolaris.org/os/licensing.
11*0Sstevel@tonic-gate * See the License for the specific language governing permissions
12*0Sstevel@tonic-gate * and limitations under the License.
13*0Sstevel@tonic-gate *
14*0Sstevel@tonic-gate * When distributing Covered Code, include this CDDL HEADER in each
15*0Sstevel@tonic-gate * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16*0Sstevel@tonic-gate * If applicable, add the following below this CDDL HEADER, with the
17*0Sstevel@tonic-gate * fields enclosed by brackets "[]" replaced with your own identifying
18*0Sstevel@tonic-gate * information: Portions Copyright [yyyy] [name of copyright owner]
19*0Sstevel@tonic-gate *
20*0Sstevel@tonic-gate * CDDL HEADER END
21*0Sstevel@tonic-gate */
22*0Sstevel@tonic-gate/*
23*0Sstevel@tonic-gate *	Copyright (c) 1988 AT&T
24*0Sstevel@tonic-gate *	  All Rights Reserved
25*0Sstevel@tonic-gate *
26*0Sstevel@tonic-gate *
27*0Sstevel@tonic-gate * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
28*0Sstevel@tonic-gate * Use is subject to license terms.
29*0Sstevel@tonic-gate */
30*0Sstevel@tonic-gate#pragma ident	"%Z%%M%	%I%	%E% SMI"
31*0Sstevel@tonic-gate
32*0Sstevel@tonic-gate/*
33*0Sstevel@tonic-gate * Bootstrap routine for run-time linker.
34*0Sstevel@tonic-gate * We get control from exec which has loaded our text and
35*0Sstevel@tonic-gate * data into the process' address space and created the process
36*0Sstevel@tonic-gate * stack.
37*0Sstevel@tonic-gate *
38*0Sstevel@tonic-gate * On entry, the process stack looks like this:
39*0Sstevel@tonic-gate *
40*0Sstevel@tonic-gate *	#			# <- %esp
41*0Sstevel@tonic-gate *	#_______________________#  high addresses
42*0Sstevel@tonic-gate *	#	strings		#
43*0Sstevel@tonic-gate *	#_______________________#
44*0Sstevel@tonic-gate *	#	0 word		#
45*0Sstevel@tonic-gate *	#_______________________#
46*0Sstevel@tonic-gate *	#	Auxiliary	#
47*0Sstevel@tonic-gate *	#	entries		#
48*0Sstevel@tonic-gate *	#	...		#
49*0Sstevel@tonic-gate *	#	(size varies)	#
50*0Sstevel@tonic-gate *	#_______________________#
51*0Sstevel@tonic-gate *	#	0 word		#
52*0Sstevel@tonic-gate *	#_______________________#
53*0Sstevel@tonic-gate *	#	Environment	#
54*0Sstevel@tonic-gate *	#	pointers	#
55*0Sstevel@tonic-gate *	#	...		#
56*0Sstevel@tonic-gate *	#	(one word each)	#
57*0Sstevel@tonic-gate *	#_______________________#
58*0Sstevel@tonic-gate *	#	0 word		#
59*0Sstevel@tonic-gate *	#_______________________#
60*0Sstevel@tonic-gate *	#	Argument	# low addresses
61*0Sstevel@tonic-gate *	#	pointers	#
62*0Sstevel@tonic-gate *	#	Argc words	#
63*0Sstevel@tonic-gate *	#_______________________#
64*0Sstevel@tonic-gate *	#	argc		#
65*0Sstevel@tonic-gate *	#_______________________# <- %ebp
66*0Sstevel@tonic-gate *
67*0Sstevel@tonic-gate *
68*0Sstevel@tonic-gate * We must calculate the address at which ld.so was loaded,
69*0Sstevel@tonic-gate * find the addr of the dynamic section of ld.so, of argv[0], and  of
70*0Sstevel@tonic-gate * the process' environment pointers - and pass the thing to _setup
71*0Sstevel@tonic-gate * to handle.  We then call _rtld - on return we jump to the entry
72*0Sstevel@tonic-gate * point for the a.out.
73*0Sstevel@tonic-gate */
74*0Sstevel@tonic-gate
75*0Sstevel@tonic-gate#if	defined(lint)
76*0Sstevel@tonic-gate
77*0Sstevel@tonic-gateextern	unsigned long	_setup();
78*0Sstevel@tonic-gateextern	void		atexit_fini();
79*0Sstevel@tonic-gatevoid
80*0Sstevel@tonic-gatemain()
81*0Sstevel@tonic-gate{
82*0Sstevel@tonic-gate	(void) _setup();
83*0Sstevel@tonic-gate	atexit_fini();
84*0Sstevel@tonic-gate}
85*0Sstevel@tonic-gate
86*0Sstevel@tonic-gate#else
87*0Sstevel@tonic-gate
88*0Sstevel@tonic-gate#include	<link.h>
89*0Sstevel@tonic-gate
90*0Sstevel@tonic-gate	.file	"boot.s"
91*0Sstevel@tonic-gate	.text
92*0Sstevel@tonic-gate	.globl	_rt_boot
93*0Sstevel@tonic-gate	.globl	_setup
94*0Sstevel@tonic-gate	.globl	_GLOBAL_OFFSET_TABLE_
95*0Sstevel@tonic-gate	.type	_rt_boot,@function
96*0Sstevel@tonic-gate	.align	4
97*0Sstevel@tonic-gate
98*0Sstevel@tonic-gate_rt_alias:
99*0Sstevel@tonic-gate	jmp	.get_ip			/ in case we were invoked from libc.so
100*0Sstevel@tonic-gate_rt_boot:
101*0Sstevel@tonic-gate	movl	%esp,%ebp		/ save for referencing args
102*0Sstevel@tonic-gate	subl	$EB_MAX_SIZE32,%esp	/ make room for a max sized boot vector
103*0Sstevel@tonic-gate	movl	%esp,%esi		/ use esi as a pointer to &eb[0]
104*0Sstevel@tonic-gate	movl	$EB_ARGV,0(%esi)	/ set up tag for argv
105*0Sstevel@tonic-gate	leal	4(%ebp),%eax		/ get address of argv
106*0Sstevel@tonic-gate	movl	%eax,4(%esi)		/ put after tag
107*0Sstevel@tonic-gate	movl	$EB_ENVP,8(%esi)	/ set up tag for envp
108*0Sstevel@tonic-gate	movl	(%ebp),%eax		/ get # of args
109*0Sstevel@tonic-gate	addl	$2,%eax			/ one for the zero & one for argc
110*0Sstevel@tonic-gate	leal	(%ebp,%eax,4),%edi	/ now points past args & @ envp
111*0Sstevel@tonic-gate	movl	%edi,12(%esi)		/ set envp
112*0Sstevel@tonic-gate.L0:	addl	$4,%edi			/ next
113*0Sstevel@tonic-gate	cmpl	$0,-4(%edi)		/ search for 0 at end of env
114*0Sstevel@tonic-gate	jne	.L0
115*0Sstevel@tonic-gate	movl	$EB_AUXV,16(%esi)	/ set up tag for auxv
116*0Sstevel@tonic-gate	movl	%edi,20(%esi)		/ point to auxv
117*0Sstevel@tonic-gate	movl	$EB_NULL,24(%esi)	/ set up NULL tag
118*0Sstevel@tonic-gate.get_ip:
119*0Sstevel@tonic-gate	call	.L1			/ only way to get IP into a register
120*0Sstevel@tonic-gate.L1:
121*0Sstevel@tonic-gate	popl	%ebx			/ pop the IP we just "pushed"
122*0Sstevel@tonic-gate	addl	$_GLOBAL_OFFSET_TABLE_+[.-.L1],%ebx
123*0Sstevel@tonic-gate	pushl	(%ebx)			/ address of dynamic structure
124*0Sstevel@tonic-gate	pushl	%esi			/ push &eb[0]
125*0Sstevel@tonic-gate
126*0Sstevel@tonic-gate	call	_setup@PLT		/ _setup(&eb[0], _DYNAMIC)
127*0Sstevel@tonic-gate	movl	%ebp,%esp		/ release stack frame
128*0Sstevel@tonic-gate
129*0Sstevel@tonic-gate	movl	atexit_fini@GOT(%ebx), %edx
130*0Sstevel@tonic-gate	jmp	*%eax 			/ transfer control to a.out
131*0Sstevel@tonic-gate	.size	_rt_boot,.-_rt_boot
132*0Sstevel@tonic-gate
133*0Sstevel@tonic-gate#endif
134