1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
|
/*
* Architecture specific code used by dl-startup.c
* Copyright (C) 2016 Waldemar Brodkorb <wbx@uclibc-ng.org>
* Ported from GNU libc
* Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball.
*/
/* Copyright (C) 1995-2016 Free Software Foundation, Inc.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public License as
published by the Free Software Foundation; either version 2.1 of the
License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <features.h>
__asm__("\
.text \n\
.globl _start \n\
.type _start, %function \n\
.globl _dl_start_user \n\
.type _dl_start_user, %function \n\
_start: \n\
mov x0, sp \n\
bl _dl_start \n\
// returns user entry point in x0 \n\
mov x21, x0 \n\
_dl_start_user: \n\
// get the original arg count \n\
ldr x1, [sp] \n\
// get the argv address \n\
add x2, sp, #(1<<3) \n\
// get _dl_skip_args to see if we were \n\
// invoked as an executable \n\
adrp x4, _dl_skip_args \n\
ldr w4, [x4, #:lo12:_dl_skip_args] \n\
// do we need to adjust argc/argv \n\
cmp w4, 0 \n\
beq .L_done_stack_adjust \n\
// subtract _dl_skip_args from original arg count \n\
sub x1, x1, x4 \n\
// store adjusted argc back to stack \n\
str x1, [sp] \n\
// find the first unskipped argument \n\
mov x3, x2 \n\
add x4, x2, x4, lsl #3 \n\
// shuffle envp down \n\
1: ldr x5, [x4], #(1<<3) \n\
str x5, [x3], #(1<<3) \n\
cmp x5, #0 \n\
bne 1b \n\
// shuffle auxv down \n\
1: ldp x0, x5, [x4, #(2<<3)]! \n\
stp x0, x5, [x3], #(2<<3) \n\
cmp x0, #0 \n\
bne 1b \n\
.L_done_stack_adjust: \n\
// compute envp \n\
add x3, x2, x1, lsl #3 \n\
add x3, x3, #(1<<3) \n\
// load the finalizer function \n\
adrp x0, _dl_fini \n\
add x0, x0, #:lo12:_dl_fini \n\
// jump to the user_s entry point \n\
br x21 \n\
");
/* Get a pointer to the argv array. On many platforms this can be just
* the address of the first argument, on other platforms we need to
* do something a little more subtle here. */
#define GET_ARGV(ARGVP, ARGS) ARGVP = (((unsigned long*)ARGS)+1)
/* Handle relocation of the symbols in the dynamic loader. */
static __always_inline
void PERFORM_BOOTSTRAP_RELOC(ELF_RELOC *rpnt, ElfW(Addr) *reloc_addr,
ElfW(Addr) symbol_addr, ElfW(Addr) load_addr, ElfW(Addr) *sym)
{
switch (ELF_R_TYPE(rpnt->r_info)) {
case R_AARCH64_NONE:
break;
case R_AARCH64_ABS64:
case R_AARCH64_GLOB_DAT:
case R_AARCH64_JUMP_SLOT:
*reloc_addr = symbol_addr + rpnt->r_addend;
break;
default:
_dl_exit(1);
}
}
|