xref: /illumos-gate/usr/src/cmd/sgs/rtld/amd64/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 *	#			# <- %rsp
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 *	#_______________________# <- %rbp
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_rt_alias:
98*5d9d9091SRichard Lowe	/ in case we were invoked from libc.so
99*5d9d9091SRichard Lowe	jmp	.get_got
100*5d9d9091SRichard Lowe_rt_boot:
101*5d9d9091SRichard Lowe	/ save for referencing args
102*5d9d9091SRichard Lowe	movq	%rsp,%rbp
103*5d9d9091SRichard Lowe	/ make room for a max sized boot vector
104*5d9d9091SRichard Lowe	subq	$EB_MAX_SIZE64,%rsp
105*5d9d9091SRichard Lowe	/ use esi as a pointer to &eb[0]
106*5d9d9091SRichard Lowe	movq	%rsp,%rsi
107*5d9d9091SRichard Lowe	/ set up tag for argv
108*5d9d9091SRichard Lowe	movq	$EB_ARGV,0(%rsi)
109*5d9d9091SRichard Lowe	/ get address of argv
110*5d9d9091SRichard Lowe	leaq	8(%rbp),%rax
111*5d9d9091SRichard Lowe	/ put after tag
112*5d9d9091SRichard Lowe	movq	%rax,8(%rsi)
113*5d9d9091SRichard Lowe	/ set up tag for envp
114*5d9d9091SRichard Lowe	movq	$EB_ENVP,16(%rsi)
115*5d9d9091SRichard Lowe	/ get # of args
116*5d9d9091SRichard Lowe	movq	(%rbp),%rax
117*5d9d9091SRichard Lowe	/ one for the zero & one for argc
118*5d9d9091SRichard Lowe	addq	$2,%rax
119*5d9d9091SRichard Lowe	/ now points past args & @ envp
120*5d9d9091SRichard Lowe	leaq	(%rbp,%rax,8),%rdi
121*5d9d9091SRichard Lowe	/ set envp
122*5d9d9091SRichard Lowe	movq	%rdi,24(%rsi)
123*5d9d9091SRichard Lowe	/ next
124*5d9d9091SRichard Lowe.L0:	addq	$8,%rdi
125*5d9d9091SRichard Lowe	/ search for 0 at end of env
126*5d9d9091SRichard Lowe	cmpq	$0,-8(%rdi)
127*5d9d9091SRichard Lowe	jne	.L0
128*5d9d9091SRichard Lowe	/ set up tag for auxv
129*5d9d9091SRichard Lowe	movq	$EB_AUXV,32(%rsi)
130*5d9d9091SRichard Lowe	/ point to auxv
131*5d9d9091SRichard Lowe	movq	%rdi,40(%rsi)
132*5d9d9091SRichard Lowe	/ set up NULL tag
133*5d9d9091SRichard Lowe	movq	$EB_NULL,48(%rsi)
134*5d9d9091SRichard Lowe
135*5d9d9091SRichard Lowe	/ arg1 - address of &eb[0]
136*5d9d9091SRichard Lowe	movq	%rsi, %rdi
137*5d9d9091SRichard Lowe.get_got:
138*5d9d9091SRichard Lowe	leaq	_GLOBAL_OFFSET_TABLE_(%rip), %rbx
139*5d9d9091SRichard Lowe	/ addq	$_GLOBAL_OFFSET_TABLE_, %rbx
140*5d9d9091SRichard Lowe	movq	%rbx,%r9
141*5d9d9091SRichard Lowe	// addq	$[.L2-.L1], %rbx
142*5d9d9091SRichard Lowe	movq	%rbx,%r10
143*5d9d9091SRichard Lowe
144*5d9d9091SRichard Lowe	movq	(%rbx),%rsi
145*5d9d9091SRichard Lowe
146*5d9d9091SRichard Lowe	/ _setup(&eb[0], _DYNAMIC)
147*5d9d9091SRichard Lowe	call	_setup@PLT
148*5d9d9091SRichard Lowe	/ release stack frame
149*5d9d9091SRichard Lowe	movq	%rbp,%rsp
150*5d9d9091SRichard Lowe
151*5d9d9091SRichard Lowe	movq	atexit_fini@GOTPCREL(%rip), %rdx
152*5d9d9091SRichard Lowe	/ transfer control to the executable
153*5d9d9091SRichard Lowe	jmp	*%rax
154*5d9d9091SRichard Lowe	.size	_rt_boot,.-_rt_boot
155*5d9d9091SRichard Lowe#endif
156