xref: /illumos-gate/usr/src/cmd/sgs/rtld/i386/boot.S (revision 5d9d9091f564c198a760790b0bfa72c44e17912b)
1*5d9d9091SRichard Lowe/*
2*5d9d9091SRichard Lowe * CDDL HEADER START
3*5d9d9091SRichard Lowe *
4*5d9d9091SRichard Lowe * The contents of this file are subject to the terms of the
5*5d9d9091SRichard Lowe * Common Development and Distribution License, Version 1.0 only
6*5d9d9091SRichard Lowe * (the "License").  You may not use this file except in compliance
7*5d9d9091SRichard Lowe * with the License.
8*5d9d9091SRichard Lowe *
9*5d9d9091SRichard Lowe * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10*5d9d9091SRichard Lowe * or http://www.opensolaris.org/os/licensing.
11*5d9d9091SRichard Lowe * See the License for the specific language governing permissions
12*5d9d9091SRichard Lowe * and limitations under the License.
13*5d9d9091SRichard Lowe *
14*5d9d9091SRichard Lowe * When distributing Covered Code, include this CDDL HEADER in each
15*5d9d9091SRichard Lowe * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16*5d9d9091SRichard Lowe * If applicable, add the following below this CDDL HEADER, with the
17*5d9d9091SRichard Lowe * fields enclosed by brackets "[]" replaced with your own identifying
18*5d9d9091SRichard Lowe * information: Portions Copyright [yyyy] [name of copyright owner]
19*5d9d9091SRichard Lowe *
20*5d9d9091SRichard Lowe * CDDL HEADER END
21*5d9d9091SRichard Lowe */
22*5d9d9091SRichard Lowe/*
23*5d9d9091SRichard Lowe *	Copyright (c) 1988 AT&T
24*5d9d9091SRichard Lowe *	  All Rights Reserved
25*5d9d9091SRichard Lowe *
26*5d9d9091SRichard Lowe *
27*5d9d9091SRichard Lowe * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
28*5d9d9091SRichard Lowe * Use is subject to license terms.
29*5d9d9091SRichard Lowe */
30*5d9d9091SRichard Lowe
31*5d9d9091SRichard Lowe/*
32*5d9d9091SRichard Lowe * Bootstrap routine for run-time linker.
33*5d9d9091SRichard Lowe * We get control from exec which has loaded our text and
34*5d9d9091SRichard Lowe * data into the process' address space and created the process
35*5d9d9091SRichard Lowe * stack.
36*5d9d9091SRichard Lowe *
37*5d9d9091SRichard Lowe * On entry, the process stack looks like this:
38*5d9d9091SRichard Lowe *
39*5d9d9091SRichard Lowe *	#			# <- %esp
40*5d9d9091SRichard Lowe *	#_______________________#  high addresses
41*5d9d9091SRichard Lowe *	#	strings		#
42*5d9d9091SRichard Lowe *	#_______________________#
43*5d9d9091SRichard Lowe *	#	0 word		#
44*5d9d9091SRichard Lowe *	#_______________________#
45*5d9d9091SRichard Lowe *	#	Auxiliary	#
46*5d9d9091SRichard Lowe *	#	entries		#
47*5d9d9091SRichard Lowe *	#	...		#
48*5d9d9091SRichard Lowe *	#	(size varies)	#
49*5d9d9091SRichard Lowe *	#_______________________#
50*5d9d9091SRichard Lowe *	#	0 word		#
51*5d9d9091SRichard Lowe *	#_______________________#
52*5d9d9091SRichard Lowe *	#	Environment	#
53*5d9d9091SRichard Lowe *	#	pointers	#
54*5d9d9091SRichard Lowe *	#	...		#
55*5d9d9091SRichard Lowe *	#	(one word each)	#
56*5d9d9091SRichard Lowe *	#_______________________#
57*5d9d9091SRichard Lowe *	#	0 word		#
58*5d9d9091SRichard Lowe *	#_______________________#
59*5d9d9091SRichard Lowe *	#	Argument	# low addresses
60*5d9d9091SRichard Lowe *	#	pointers	#
61*5d9d9091SRichard Lowe *	#	Argc words	#
62*5d9d9091SRichard Lowe *	#_______________________#
63*5d9d9091SRichard Lowe *	#	argc		#
64*5d9d9091SRichard Lowe *	#_______________________# <- %ebp
65*5d9d9091SRichard Lowe *
66*5d9d9091SRichard Lowe *
67*5d9d9091SRichard Lowe * We must calculate the address at which ld.so was loaded,
68*5d9d9091SRichard Lowe * find the addr of the dynamic section of ld.so, of argv[0], and  of
69*5d9d9091SRichard Lowe * the process' environment pointers - and pass the thing to _setup
70*5d9d9091SRichard Lowe * to handle.  We then call _rtld - on return we jump to the entry
71*5d9d9091SRichard Lowe * point for the executable.
72*5d9d9091SRichard Lowe */
73*5d9d9091SRichard Lowe
74*5d9d9091SRichard Lowe#if	defined(lint)
75*5d9d9091SRichard Lowe
76*5d9d9091SRichard Loweextern	unsigned long	_setup();
77*5d9d9091SRichard Loweextern	void		atexit_fini();
78*5d9d9091SRichard Lowevoid
79*5d9d9091SRichard Lowemain()
80*5d9d9091SRichard Lowe{
81*5d9d9091SRichard Lowe	(void) _setup();
82*5d9d9091SRichard Lowe	atexit_fini();
83*5d9d9091SRichard Lowe}
84*5d9d9091SRichard Lowe
85*5d9d9091SRichard Lowe#else
86*5d9d9091SRichard Lowe
87*5d9d9091SRichard Lowe#include	<link.h>
88*5d9d9091SRichard Lowe
89*5d9d9091SRichard Lowe	.file	"boot.s"
90*5d9d9091SRichard Lowe	.text
91*5d9d9091SRichard Lowe	.globl	_rt_boot
92*5d9d9091SRichard Lowe	.globl	_setup
93*5d9d9091SRichard Lowe	.globl	_GLOBAL_OFFSET_TABLE_
94*5d9d9091SRichard Lowe	.type	_rt_boot,@function
95*5d9d9091SRichard Lowe	.align	4
96*5d9d9091SRichard Lowe
97*5d9d9091SRichard Lowe	/ init is called from the _init symbol in the CRT, however .init_array
98*5d9d9091SRichard Lowe	/ are called "naturally" from call_init.  Because of that, we need the
99*5d9d9091SRichard Lowe	/ stack aligned here so that initializers called via _array sections may
100*5d9d9091SRichard Lowe	/ safely use SIMD instructions.
101*5d9d9091SRichard Lowe_rt_alias:
102*5d9d9091SRichard Lowe	jmp	.get_ip			/ in case we were invoked from libc.so
103*5d9d9091SRichard Lowe_rt_boot:
104*5d9d9091SRichard Lowe	movl	%esp,%ebp		/ save for referencing args
105*5d9d9091SRichard Lowe	subl	$EB_MAX_SIZE32,%esp	/ make room for a max sized boot vector
106*5d9d9091SRichard Lowe	andl	$-16,%esp
107*5d9d9091SRichard Lowe	subl	$8,%esp
108*5d9d9091SRichard Lowe	movl	%esp,%esi		/ use esi as a pointer to &eb[0]
109*5d9d9091SRichard Lowe	movl	$EB_ARGV,0(%esi)	/ set up tag for argv
110*5d9d9091SRichard Lowe	leal	4(%ebp),%eax		/ get address of argv
111*5d9d9091SRichard Lowe	movl	%eax,4(%esi)		/ put after tag
112*5d9d9091SRichard Lowe	movl	$EB_ENVP,8(%esi)	/ set up tag for envp
113*5d9d9091SRichard Lowe	movl	(%ebp),%eax		/ get # of args
114*5d9d9091SRichard Lowe	addl	$2,%eax			/ one for the zero & one for argc
115*5d9d9091SRichard Lowe	leal	(%ebp,%eax,4),%edi	/ now points past args & @ envp
116*5d9d9091SRichard Lowe	movl	%edi,12(%esi)		/ set envp
117*5d9d9091SRichard Lowe.L0:	addl	$4,%edi			/ next
118*5d9d9091SRichard Lowe	cmpl	$0,-4(%edi)		/ search for 0 at end of env
119*5d9d9091SRichard Lowe	jne	.L0
120*5d9d9091SRichard Lowe	movl	$EB_AUXV,16(%esi)	/ set up tag for auxv
121*5d9d9091SRichard Lowe	movl	%edi,20(%esi)		/ point to auxv
122*5d9d9091SRichard Lowe	movl	$EB_NULL,24(%esi)	/ set up NULL tag
123*5d9d9091SRichard Lowe.get_ip:
124*5d9d9091SRichard Lowe	call	.L1			/ only way to get IP into a register
125*5d9d9091SRichard Lowe.L1:
126*5d9d9091SRichard Lowe	popl	%ebx			/ pop the IP we just "pushed"
127*5d9d9091SRichard Lowe	addl	$_GLOBAL_OFFSET_TABLE_+[.-.L1],%ebx
128*5d9d9091SRichard Lowe	pushl	(%ebx)			/ address of dynamic structure
129*5d9d9091SRichard Lowe	pushl	%esi			/ push &eb[0]
130*5d9d9091SRichard Lowe
131*5d9d9091SRichard Lowe	call	_setup@PLT		/ _setup(&eb[0], _DYNAMIC)
132*5d9d9091SRichard Lowe	movl	%ebp,%esp		/ release stack frame
133*5d9d9091SRichard Lowe
134*5d9d9091SRichard Lowe	movl	atexit_fini@GOT(%ebx), %edx
135*5d9d9091SRichard Lowe	jmp	*%eax			/ transfer control to the executable
136*5d9d9091SRichard Lowe	.size	_rt_boot,.-_rt_boot
137*5d9d9091SRichard Lowe
138*5d9d9091SRichard Lowe#endif
139