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1 /*
2  * Copyright (C) 2013 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 #pragma once
30 
31 /* https://github.com/android/ndk/issues/1422 */
32 #include <features.h>
33 
34 #include <asm/unistd.h> /* For system call numbers. */
35 #define MAX_ERRNO 4095  /* For recognizing system call error returns. */
36 
37 #define __bionic_asm_custom_entry(f)
38 #define __bionic_asm_custom_end(f)
39 #define __bionic_asm_function_type @function
40 #define __bionic_asm_custom_note_gnu_section()
41 
42 #if defined(__aarch64__)
43 #include <private/bionic_asm_arm64.h>
44 #elif defined(__arm__)
45 #include <private/bionic_asm_arm.h>
46 #elif defined(__i386__)
47 #include <private/bionic_asm_x86.h>
48 #elif defined(__riscv)
49 #include <private/bionic_asm_riscv64.h>
50 #elif defined(__x86_64__)
51 #include <private/bionic_asm_x86_64.h>
52 #endif
53 
54 // Starts a normal assembler routine.
55 #define ENTRY(__f) __ENTRY_WITH_BINDING(__f, .globl)
56 
57 // Starts an assembler routine with hidden visibility.
58 #define ENTRY_PRIVATE(__f)           \
59   __ENTRY_WITH_BINDING(__f, .globl); \
60   .hidden __f;
61 
62 // Starts an assembler routine that's weak so native bridges can override it.
63 #define ENTRY_WEAK_FOR_NATIVE_BRIDGE(__f) __ENTRY_WITH_BINDING(__f, .weak)
64 
65 // Starts an assembler routine with hidden visibility and no DWARF information.
66 // Only used for internal functions passed via sa_restorer.
67 // TODO: can't we just delete all those and let the kernel do its thing?
68 #define ENTRY_NO_DWARF_PRIVATE(__f) \
69   __ENTRY_NO_DWARF(__f, .globl);    \
70   .hidden __f;
71 
72 // (Implementation detail.)
73 #define __ENTRY_NO_DWARF(__f, __binding) \
74   .text;                                 \
75   __binding __f;                         \
76   .balign __bionic_asm_align;            \
77   .type __f, __bionic_asm_function_type; \
78   __f:                                   \
79   __bionic_asm_custom_entry(__f);
80 
81 // (Implementation detail.)
82 #define __ENTRY_WITH_BINDING(__f, __binding) \
83   __ENTRY_NO_DWARF(__f, __binding);          \
84   .cfi_startproc;
85 
86 // Ends a normal assembler routine.
87 #define END(__f) \
88   .cfi_endproc;  \
89   END_NO_DWARF(__f)
90 
91 // Ends an assembler routine with no DWARF information.
92 // Only used for internal functions passed via sa_restorer.
93 // TODO: can't we just delete all those and let the kernel do its thing?
94 #define END_NO_DWARF(__f) \
95   .size __f, .- __f;      \
96   __bionic_asm_custom_end(__f)
97 
98 // Creates an alias `alias` for the symbol `original`.
99 #define ALIAS_SYMBOL(alias, original) \
100   .globl alias;                       \
101   .equ alias, original
102 
103 // Creates an alias `alias` for the symbol `original` that's weak so it can be
104 // separately overridden by native bridges.
105 #define ALIAS_SYMBOL_WEAK_FOR_NATIVE_BRIDGE(alias, original) \
106   .weak alias;                                               \
107   .equ alias, original
108 
109 // Adds a GNU property ELF note. Important on arm64 to declare PAC/BTI support.
110 #define NOTE_GNU_PROPERTY() __bionic_asm_custom_note_gnu_section()
111 
112 // Gives local labels a more convenient and readable syntax.
113 #define L(__label) .L##__label
114