1 /* Mach-O compact unwind encoding.
2    Copyright (C) 2014-2016 Free Software Foundation, Inc.
3 
4    This file is part of BFD, the Binary File Descriptor library.
5 
6    This program is free software; you can redistribute it and/or modify
7    it under the terms of the GNU General Public License as published by
8    the Free Software Foundation; either version 3 of the License, or
9    (at your option) any later version.
10 
11    This program is distributed in the hope that it will be useful,
12    but WITHOUT ANY WARRANTY; without even the implied warranty of
13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14    GNU General Public License for more details.
15 
16    You should have received a copy of the GNU General Public License
17    along with this program; if not, write to the Free Software
18    Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
19    MA 02110-1301, USA.  */
20 
21 #ifndef _MACH_O_UNWIND_H
22 #define _MACH_O_UNWIND_H
23 
24 /* Encodings bits for all cpus.  */
25 #define MACH_O_UNWIND_IS_NOT_FUNCTION_START 0x80000000
26 #define MACH_O_UNWIND_HAS_LSDA              0x40000000
27 #define MACH_O_UNWIND_PERSONALITY_MASK      0x30000000
28 #define MACH_O_UNWIND_PERSONALITY_SHIFT     28
29 
30 /* Encodings for x86-64.  */
31 
32 /* Kind of encoding (4 bits).  */
33 #define MACH_O_UNWIND_X86_64_MODE_MASK       0x0f000000
34 
35 /* Frame is RBP based, using the standard sequence: push %rbp; mov %rsp, %rbp.
36    Non-volatile registers must be saved in the stack starting at %rbp-8 to
37    %rbp-2040 (offset is encoded in offset bits * 8).  Registers saved are
38    encoded in registers bits, 3 bits per register.  */
39 #define MACH_O_UNWIND_X86_64_MODE_RBP_FRAME  0x01000000
40 #define  MACH_O_UNWIND_X86_64_RBP_FRAME_REGSITERS 0x00007FFF
41 #define  MACH_O_UNWIND_X86_64_RBP_FRAME_OFFSET    0x00FF0000
42 
43 /* Frameless function, with a small stack size.  */
44 #define MACH_O_UNWIND_X86_64_MODE_STACK_IMMD 0x02000000
45 #define  MACH_O_UNWIND_X86_64_FRAMELESS_STACK_SIZE      0x00FF0000
46 #define  MACH_O_UNWIND_X86_64_FRAMELESS_REG_COUNT       0x00001C00
47 #define  MACH_O_UNWIND_X86_64_FRAMELESS_REG_PERMUTATION 0x000003FF
48 
49 /* Frameless function, with a larger stack size. The stack size is the sum
50    of the X in subq $X,%rsp (address of X is at function + stack size bits)
51    and stack adjust.  */
52 #define MACH_O_UNWIND_X86_64_MODE_STACK_IND          0x03000000
53 #define  MACH_O_UNWIND_X86_64_FRAMELESS_STACK_ADJUST 0x0000E000
54 
55 /* Use dwarf.  */
56 #define MACH_O_UNWIND_X86_64_MODE_DWARF      0x04000000
57 #define  MACH_O_UNWIND_X86_64_DWARF_SECTION_OFFSET 0x00ffffff
58 
59 /* Registers.  */
60 #define MACH_O_UNWIND_X86_64_REG_NONE 0
61 #define MACH_O_UNWIND_X86_64_REG_RBX 1
62 #define MACH_O_UNWIND_X86_64_REG_R12 2
63 #define MACH_O_UNWIND_X86_64_REG_R13 3
64 #define MACH_O_UNWIND_X86_64_REG_R14 4
65 #define MACH_O_UNWIND_X86_64_REG_R15 5
66 #define MACH_O_UNWIND_X86_64_REG_RBP 6
67 
68 /* Encodings for x86 (almot the same as x86-64).  */
69 
70 /* Kind of encoding (4 bits).  */
71 #define MACH_O_UNWIND_X86_MODE_MASK       0x0f000000
72 
73 /* Frame is EBP based, using the standard sequence: push %ebp; mov %esp, %ebp.
74    Non-volatile registers must be saved in the stack starting at %ebp-4 to
75    %ebp-240 (offset is encoded in offset bits * 4).  Registers saved are
76    encoded in registers bits, 3 bits per register.  */
77 #define MACH_O_UNWIND_X86_MODE_EBP_FRAME  0x01000000
78 #define  MACH_O_UNWIND_X86_EBP_FRAME_REGSITERS 0x00007FFF
79 #define  MACH_O_UNWIND_X86_EBP_FRAME_OFFSET    0x00FF0000
80 
81 /* Frameless function, with a small stack size.  */
82 #define MACH_O_UNWIND_X86_MODE_STACK_IMMD 0x02000000
83 #define  MACH_O_UNWIND_X86_FRAMELESS_STACK_SIZE      0x00FF0000
84 #define  MACH_O_UNWIND_X86_FRAMELESS_REG_COUNT       0x00001C00
85 #define  MACH_O_UNWIND_X86_FRAMELESS_REG_PERMUTATION 0x000003FF
86 
87 /* Frameless function, with a larger stack size. The stack size is the sum
88    of the X in subq $X,%esp (address of X is at function + stack size bits)
89    and stack adjust.  */
90 #define MACH_O_UNWIND_X86_MODE_STACK_IND          0x03000000
91 #define  MACH_O_UNWIND_X86_FRAMELESS_STACK_ADJUST 0x0000E000
92 
93 /* Use dwarf.  */
94 #define MACH_O_UNWIND_X86_MODE_DWARF      0x04000000
95 #define  MACH_O_UNWIND_X86_DWARF_SECTION_OFFSET 0x00ffffff
96 
97 /* Registers.  */
98 #define MACH_O_UNWIND_X86_REG_NONE 0
99 #define MACH_O_UNWIND_X86_REG_EBX 1
100 #define MACH_O_UNWIND_X86_REG_ECX 2
101 #define MACH_O_UNWIND_X86_REG_EDX 3
102 #define MACH_O_UNWIND_X86_REG_EDI 4
103 #define MACH_O_UNWIND_X86_REG_ESI 5
104 #define MACH_O_UNWIND_X86_REG_EBP 6
105 
106 /* Encodings for arm64.  */
107 
108 #define MACH_O_UNWIND_ARM64_MODE_MASK		0x0f000000
109 
110 /* Leaf function:  FP/LR are *not* saved, none or some non-volatile registers
111    are saved, stack is allocated.  The size of the frame (register saved and
112    memory) is encoded in STACK_SIZE in 16 byte units.  */
113 #define MACH_O_UNWIND_ARM64_MODE_FRAMELESS	0x02000000
114 
115 #define MACH_O_UNWIND_ARM64_MODE_DWARF		0x03000000
116 
117 /* Standard frame: FP/LR are pushed, SP is copied to FP, then non-volatile
118    registers are saved.  */
119 #define MACH_O_UNWIND_ARM64_MODE_FRAME		0x04000000
120 
121 /* Registers (for FRAME).  */
122 #define MACH_O_UNWIND_ARM64_FRAME_X19_X20_PAIR	0x00000001
123 #define MACH_O_UNWIND_ARM64_FRAME_X21_X22_PAIR	0x00000002
124 #define MACH_O_UNWIND_ARM64_FRAME_X23_X24_PAIR	0x00000004
125 #define MACH_O_UNWIND_ARM64_FRAME_X25_X26_PAIR	0x00000008
126 #define MACH_O_UNWIND_ARM64_FRAME_X27_X28_PAIR	0x00000010
127 #define MACH_O_UNWIND_ARM64_FRAME_D8_D9_PAIR	0x00000100
128 #define MACH_O_UNWIND_ARM64_FRAME_D10_D11_PAIR	0x00000200
129 #define MACH_O_UNWIND_ARM64_FRAME_D12_D13_PAIR	0x00000400
130 #define MACH_O_UNWIND_ARM64_FRAME_D14_D15_PAIR	0x00000800
131 
132 #define MACH_O_UNWIND_ARM64_FRAMELESS_STACK_SIZE_MASK 0x00fff000
133 #define MACH_O_UNWIND_ARM64_DWARF_SECTION_OFFSET 0x00ffffff
134 
135 /* Entry in object file (in __LD,__compact_unwind section).  */
136 
137 struct mach_o_compact_unwind_32
138 {
139   unsigned char start[4];
140   unsigned char length[4];
141   unsigned char encoding[4];
142   unsigned char personality[4];
143   unsigned char lsda[4];
144 };
145 
146 struct mach_o_compact_unwind_64
147 {
148   unsigned char start[8];
149   unsigned char length[4];
150   unsigned char encoding[4];
151   unsigned char personality[8];
152   unsigned char lsda[8];
153 };
154 
155 /* Header in images (in __TEXT,__unwind_info).  */
156 
157 #define MACH_O_UNWIND_SECTION_VERSION 1 /* Current verion in header.  */
158 struct mach_o_unwind_info_header
159 {
160   unsigned char version[4];	/* Currently MACH_O_UNWIND_SECTION_VERSION. */
161   unsigned char encodings_array_offset[4];
162   unsigned char encodings_array_count[4];
163   unsigned char personality_array_offset[4];
164   unsigned char personality_array_count[4];
165   unsigned char index_offset[4];
166   unsigned char index_count[4];
167   /* Followed by:
168      - encodings array
169        These are the encodings shared, for index < encoding_array_count
170      - personality array
171        count given by personality_array_count
172      - index entries
173        count given by index_count
174      - lsda index entries
175        last offset given by lsda offset of last index_entry.
176   */
177 };
178 
179 struct mach_o_unwind_index_entry
180 {
181   unsigned char function_offset[4];
182   unsigned char second_level_offset[4];
183   unsigned char lsda_index_offset[4];
184 };
185 
186 struct mach_o_unwind_lsda_index_entry
187 {
188   unsigned char function_offset[4];
189   unsigned char lsda_offset[4];
190 };
191 
192 /* Second level index pages.  */
193 
194 #define MACH_O_UNWIND_SECOND_LEVEL_REGULAR 2
195 struct mach_o_unwind_regular_second_level_page_header
196 {
197   unsigned char kind[4];
198   unsigned char entry_page_offset[2];
199   unsigned char entry_count[2];
200   /* Array of entries.  */
201 };
202 
203 struct mach_o_unwind_regular_second_level_entry
204 {
205   unsigned char function_offset[4];
206   unsigned char encoding[4];
207 };
208 
209 #define MACH_O_UNWIND_SECOND_LEVEL_COMPRESSED 3
210 struct mach_o_unwind_compressed_second_level_page_header
211 {
212   unsigned char kind[4];
213   unsigned char entry_page_offset[2];
214   unsigned char entry_count[2];
215   unsigned char encodings_offset[2];
216   unsigned char encodings_count[2];
217   /* Followed by entries array (one word, see below).  */
218   /* Followed by (non-common) encodings array.  */
219 };
220 
221 /* Compressed entries are one word, containing function offset and encoding
222    index.  */
223 #define MACH_O_UNWIND_INFO_COMPRESSED_ENTRY_FUNC_OFFSET(en) \
224    ((en) & 0x00FFFFFF)
225 #define MACH_O_UNWIND_INFO_COMPRESSED_ENTRY_ENCODING_INDEX(en) \
226    (((en) >> 24) & 0xFF)
227 
228 #endif /* _MACH_O_UNWIND_H */
229