1/* Special .init and .fini section support for ARM.
2 Copyright (C) 1995-2022 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 In addition to the permissions in the GNU Lesser General Public
11 License, the Free Software Foundation gives you unlimited
12 permission to link the compiled version of this file with other
13 programs, and to distribute those programs without any restriction
14 coming from the use of this file. (The GNU Lesser General Public
15 License restrictions do apply in other respects; for example, they
16 cover modification of the file, and distribution when not linked
17 into another program.)
18
19 Note that people who make modified versions of this file are not
20 obligated to grant this special exception for their modified
21 versions; it is their choice whether to do so. The GNU Lesser
22 General Public License gives permission to release a modified
23 version without this exception; this exception also makes it
24 possible to release a modified version which carries forward this
25 exception.
26
27 The GNU C Library is distributed in the hope that it will be useful,
28 but WITHOUT ANY WARRANTY; without even the implied warranty of
29 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
30 Lesser General Public License for more details.
31
32 You should have received a copy of the GNU Lesser General Public
33 License along with the GNU C Library. If not, see
34 <https://www.gnu.org/licenses/>. */
35
36/* crti.S puts a function prologue at the beginning of the .init and
37 .fini sections and defines global symbols for those addresses, so
38 they can be called as functions. The symbols _init and _fini are
39 magic and cause the linker to emit DT_INIT and DT_FINI. */
40
41/* Always build .init and .fini sections in ARM mode. */
42#define NO_THUMB
43#include <libc-symbols.h>
44#include <sysdep.h>
45
46#ifndef PREINIT_FUNCTION
47# define PREINIT_FUNCTION __gmon_start__
48#endif
49
50#ifndef PREINIT_FUNCTION_WEAK
51# define PREINIT_FUNCTION_WEAK 1
52#endif
53
54#if PREINIT_FUNCTION_WEAK
55 weak_extern (PREINIT_FUNCTION)
56#else
57 .hidden PREINIT_FUNCTION
58#endif
59
60#if PREINIT_FUNCTION_WEAK
61 .p2align 2
62 .type call_weak_fn, %function
63call_weak_fn:
64 ldr r3, .LGOT
65 ldr r2, .LGOT+4
66.LPIC:
67 add r3, pc, r3
68 ldr r2, [r3, r2]
69 cmp r2, #0
70 bxeq lr
71 b PREINIT_FUNCTION
72 .p2align 2
73.LGOT:
74 .word _GLOBAL_OFFSET_TABLE_-(.LPIC+8)
75 .word PREINIT_FUNCTION(GOT)
76#endif
77
78 .section .init,"ax",%progbits
79 .p2align 2
80 .globl _init
81 .hidden _init
82 .type _init, %function
83_init:
84 push {r3, lr}
85#if PREINIT_FUNCTION_WEAK
86 bl call_weak_fn
87#else
88 bl PREINIT_FUNCTION
89#endif
90
91 .section .fini,"ax",%progbits
92 .p2align 2
93 .globl _fini
94 .hidden _fini
95 .type _fini, %function
96_fini:
97 push {r3, lr}
98

source code of glibc/sysdeps/arm/crti.S