1 /*
2 * Copyright (C) 2012 The Android Open Source Project
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * * Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * * Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in
12 * the documentation and/or other materials provided with the
13 * distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include "../../bionic/libc_init_common.h"
30 #include <stddef.h>
31 #include <stdint.h>
32
33 #define SECTION(name) __attribute__((__section__(name)))
34 SECTION(".preinit_array") init_func_t* __PREINIT_ARRAY__ = (init_func_t*)-1;
35 SECTION(".init_array.0") init_func_t* __INIT_ARRAY__ = (init_func_t*)-1;
36 SECTION(".fini_array.0") fini_func_t* __FINI_ARRAY__ = (fini_func_t*)-1;
37 #undef SECTION
38
_start_main(void * raw_args)39 __used static void _start_main(void* raw_args) {
40 structors_array_t array;
41 array.preinit_array = &__PREINIT_ARRAY__;
42 array.init_array = &__INIT_ARRAY__;
43 array.fini_array = &__FINI_ARRAY__;
44
45 __libc_init(raw_args, NULL, &main, &array);
46 }
47
48 #define PRE ".text; .global _start; .type _start,%function; _start:"
49 #define POST "; .size _start, .-_start"
50
51 #if defined(__aarch64__)
52 __asm__(PRE "bti j; mov x29,#0; mov x30,#0; mov x0,sp; b _start_main" POST);
53 #elif defined(__arm__)
54 __asm__(PRE "mov fp,#0; mov lr,#0; mov r0,sp; b _start_main" POST);
55 #elif defined(__i386__)
56 __asm__(PRE
57 "xorl %ebp,%ebp; movl %esp,%eax; andl $~0xf,%esp; subl $12,%esp; pushl %eax;"
58 "calll _start_main" POST);
59 #elif defined(__x86_64__)
60 __asm__(PRE "xorl %ebp, %ebp; movq %rsp,%rdi; andq $~0xf,%rsp; callq _start_main" POST);
61 #else
62 #error unsupported architecture
63 #endif
64
65 #undef PRE
66 #undef POST
67
68 // On arm32 and arm64, when targeting Q and up, overalign the TLS segment to
69 // (8 * sizeof(void*)), which reserves enough space between the thread pointer
70 // and the executable's TLS segment for Bionic's TLS slots. It has the side
71 // effect of placing a 0-sized TLS segment into Android executables that don't
72 // use TLS, but this should be harmless.
73 //
74 // To ensure that the .tdata input section isn't deleted (e.g. by
75 // --gc-sections), the .text input section (which contains _start) has a
76 // relocation to the .tdata input section.
77 #if __ANDROID_API__ >= 29
78 #if defined(__arm__)
79 asm(" .section .tdata,\"awT\",%progbits\n"
80 " .p2align 5\n"
81 " .text\n"
82 " .reloc 0, R_ARM_NONE, .tdata\n");
83 #elif defined(__aarch64__)
84 asm(" .section .tdata,\"awT\",@progbits\n"
85 " .p2align 6\n"
86 " .text\n"
87 " .reloc 0, R_AARCH64_NONE, .tdata\n");
88 #endif
89 #endif
90
91 #include "__dso_handle.h"
92 #include "atexit.h"
93 #include "pthread_atfork.h"
94