1/* Special .init and .fini section support for AArch64.
2 Copyright (C) 1995-2022 Free Software Foundation, Inc.
3
4 This file is part of the GNU C Library.
5
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
10
11 In addition to the permissions in the GNU Lesser General Public
12 License, the Free Software Foundation gives you unlimited
13 permission to link the compiled version of this file with other
14 programs, and to distribute those programs without any restriction
15 coming from the use of this file. (The GNU Lesser General Public
16 License restrictions do apply in other respects; for example, they
17 cover modification of the file, and distribution when not linked
18 into another program.)
19
20 Note that people who make modified versions of this file are not
21 obligated to grant this special exception for their modified
22 versions; it is their choice whether to do so. The GNU Lesser
23 General Public License gives permission to release a modified
24 version without this exception; this exception also makes it
25 possible to release a modified version which carries forward this
26 exception.
27
28 The GNU C Library is distributed in the hope that it will be useful,
29 but WITHOUT ANY WARRANTY; without even the implied warranty of
30 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
31 Lesser General Public License for more details.
32
33 You should have received a copy of the GNU Lesser General Public
34 License along with the GNU C Library; if not, see
35 <https://www.gnu.org/licenses/>. */
36
37/* crti.S puts a function prologue at the beginning of the .init and
38 .fini sections and defines global symbols for those addresses, so
39 they can be called as functions. The symbols _init and _fini are
40 magic and cause the linker to emit DT_INIT and DT_FINI. */
41
42#include <sysdep.h>
43#include <libc-symbols.h>
44
45#ifndef PREINIT_FUNCTION
46# define PREINIT_FUNCTION __gmon_start__
47#endif
48
49#ifndef PREINIT_FUNCTION_WEAK
50# define PREINIT_FUNCTION_WEAK 1
51#endif
52
53#if PREINIT_FUNCTION_WEAK
54 weak_extern (PREINIT_FUNCTION)
55#else
56 .hidden PREINIT_FUNCTION
57#endif
58
59#if PREINIT_FUNCTION_WEAK
60 .align 2
61 .type call_weak_fn, %function
62call_weak_fn:
63 adrp x0, :got:PREINIT_FUNCTION
64 ldr PTR_REG (0), [x0, #:got_lo12:PREINIT_FUNCTION]
65 cbz x0, 1f
66 b PREINIT_FUNCTION
671:
68 RET
69 .size call_weak_fn, .-call_weak_fn
70#endif
71
72 .section .init,"ax",%progbits
73 .align 2
74 .global _init
75 .hidden _init
76 .type _init, %function
77_init:
78#if HAVE_AARCH64_PAC_RET
79 PACIASP
80#else
81 BTI_C
82#endif
83 stp x29, x30, [sp, -16]!
84 mov x29, sp
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 .align 2
93 .global _fini
94 .hidden _fini
95 .type _fini, %function
96_fini:
97#if HAVE_AARCH64_PAC_RET
98 PACIASP
99#else
100 BTI_C
101#endif
102 stp x29, x30, [sp, -16]!
103 mov x29, sp
104

source code of glibc/sysdeps/aarch64/crti.S