xref: /onnv-gate/usr/src/cmd/sgs/rtld/amd64/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 *	#			# <- %rsp
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 *	#_______________________# <- %rbp
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	/ in case we were invoked from libc.so
100*0Sstevel@tonic-gate	jmp	.get_got
101*0Sstevel@tonic-gate_rt_boot:
102*0Sstevel@tonic-gate	/ save for referencing args
103*0Sstevel@tonic-gate	movq	%rsp,%rbp
104*0Sstevel@tonic-gate	/ make room for a max sized boot vector
105*0Sstevel@tonic-gate	subq	$EB_MAX_SIZE64,%rsp
106*0Sstevel@tonic-gate	/ use esi as a pointer to &eb[0]
107*0Sstevel@tonic-gate	movq	%rsp,%rsi
108*0Sstevel@tonic-gate	/ set up tag for argv
109*0Sstevel@tonic-gate	movq	$EB_ARGV,0(%rsi)
110*0Sstevel@tonic-gate	/ get address of argv
111*0Sstevel@tonic-gate	leaq	8(%rbp),%rax
112*0Sstevel@tonic-gate	/ put after tag
113*0Sstevel@tonic-gate	movq	%rax,8(%rsi)
114*0Sstevel@tonic-gate	/ set up tag for envp
115*0Sstevel@tonic-gate	movq	$EB_ENVP,16(%rsi)
116*0Sstevel@tonic-gate	/ get # of args
117*0Sstevel@tonic-gate	movq	(%rbp),%rax
118*0Sstevel@tonic-gate	/ one for the zero & one for argc
119*0Sstevel@tonic-gate	addq	$2,%rax
120*0Sstevel@tonic-gate	/ now points past args & @ envp
121*0Sstevel@tonic-gate	leaq	(%rbp,%rax,8),%rdi
122*0Sstevel@tonic-gate	/ set envp
123*0Sstevel@tonic-gate	movq	%rdi,24(%rsi)
124*0Sstevel@tonic-gate	/ next
125*0Sstevel@tonic-gate.L0:	addq	$8,%rdi
126*0Sstevel@tonic-gate	/ search for 0 at end of env
127*0Sstevel@tonic-gate	cmpq	$0,-8(%rdi)
128*0Sstevel@tonic-gate	jne	.L0
129*0Sstevel@tonic-gate	/ set up tag for auxv
130*0Sstevel@tonic-gate	movq	$EB_AUXV,32(%rsi)
131*0Sstevel@tonic-gate	/ point to auxv
132*0Sstevel@tonic-gate	movq	%rdi,40(%rsi)
133*0Sstevel@tonic-gate	/ set up NULL tag
134*0Sstevel@tonic-gate	movq	$EB_NULL,48(%rsi)
135*0Sstevel@tonic-gate
136*0Sstevel@tonic-gate	/ arg1 - address of &eb[0]
137*0Sstevel@tonic-gate	movq	%rsi, %rdi
138*0Sstevel@tonic-gate.get_got:
139*0Sstevel@tonic-gate	leaq	_GLOBAL_OFFSET_TABLE_(%rip), %rbx
140*0Sstevel@tonic-gate	/ addq	$_GLOBAL_OFFSET_TABLE_, %rbx
141*0Sstevel@tonic-gate	movq	%rbx,%r9
142*0Sstevel@tonic-gate	// addq	$[.L2-.L1], %rbx
143*0Sstevel@tonic-gate	movq	%rbx,%r10
144*0Sstevel@tonic-gate
145*0Sstevel@tonic-gate	movq	(%rbx),%rsi
146*0Sstevel@tonic-gate
147*0Sstevel@tonic-gate	/ _setup(&eb[0], _DYNAMIC)
148*0Sstevel@tonic-gate	call	_setup@PLT
149*0Sstevel@tonic-gate	/ release stack frame
150*0Sstevel@tonic-gate	movq	%rbp,%rsp
151*0Sstevel@tonic-gate
152*0Sstevel@tonic-gate	movq	atexit_fini@GOTPCREL(%rip), %rdx
153*0Sstevel@tonic-gate	/ transfer control to a.out
154*0Sstevel@tonic-gate	jmp	*%rax
155*0Sstevel@tonic-gate	.size	_rt_boot,.-_rt_boot
156*0Sstevel@tonic-gate#endif
157