1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* |
3 | * Copyright (C) 2017 Josh Poimboeuf <jpoimboe@redhat.com> |
4 | */ |
5 | |
6 | #include <stdlib.h> |
7 | #include <string.h> |
8 | |
9 | #include <linux/objtool_types.h> |
10 | #include <asm/orc_types.h> |
11 | |
12 | #include <objtool/check.h> |
13 | #include <objtool/orc.h> |
14 | #include <objtool/warn.h> |
15 | #include <objtool/endianness.h> |
16 | |
17 | struct orc_list_entry { |
18 | struct list_head list; |
19 | struct orc_entry orc; |
20 | struct section *insn_sec; |
21 | unsigned long insn_off; |
22 | }; |
23 | |
24 | static int orc_list_add(struct list_head *orc_list, struct orc_entry *orc, |
25 | struct section *sec, unsigned long offset) |
26 | { |
27 | struct orc_list_entry *entry = malloc(sizeof(*entry)); |
28 | |
29 | if (!entry) { |
30 | WARN("malloc failed" ); |
31 | return -1; |
32 | } |
33 | |
34 | entry->orc = *orc; |
35 | entry->insn_sec = sec; |
36 | entry->insn_off = offset; |
37 | |
38 | list_add_tail(&entry->list, orc_list); |
39 | return 0; |
40 | } |
41 | |
42 | static unsigned long alt_group_len(struct alt_group *alt_group) |
43 | { |
44 | return alt_group->last_insn->offset + |
45 | alt_group->last_insn->len - |
46 | alt_group->first_insn->offset; |
47 | } |
48 | |
49 | int orc_create(struct objtool_file *file) |
50 | { |
51 | struct section *sec, *orc_sec; |
52 | unsigned int nr = 0, idx = 0; |
53 | struct orc_list_entry *entry; |
54 | struct list_head orc_list; |
55 | |
56 | struct orc_entry null = { .type = ORC_TYPE_UNDEFINED }; |
57 | |
58 | /* Build a deduplicated list of ORC entries: */ |
59 | INIT_LIST_HEAD(&orc_list); |
60 | for_each_sec(file, sec) { |
61 | struct orc_entry orc, prev_orc = {0}; |
62 | struct instruction *insn; |
63 | bool empty = true; |
64 | |
65 | if (!sec->text) |
66 | continue; |
67 | |
68 | sec_for_each_insn(file, sec, insn) { |
69 | struct alt_group *alt_group = insn->alt_group; |
70 | int i; |
71 | |
72 | if (!alt_group) { |
73 | if (init_orc_entry(&orc, insn->cfi, insn)) |
74 | return -1; |
75 | if (!memcmp(&prev_orc, &orc, sizeof(orc))) |
76 | continue; |
77 | if (orc_list_add(orc_list: &orc_list, orc: &orc, sec, |
78 | offset: insn->offset)) |
79 | return -1; |
80 | nr++; |
81 | prev_orc = orc; |
82 | empty = false; |
83 | continue; |
84 | } |
85 | |
86 | /* |
87 | * Alternatives can have different stack layout |
88 | * possibilities (but they shouldn't conflict). |
89 | * Instead of traversing the instructions, use the |
90 | * alt_group's flattened byte-offset-addressed CFI |
91 | * array. |
92 | */ |
93 | for (i = 0; i < alt_group_len(alt_group); i++) { |
94 | struct cfi_state *cfi = alt_group->cfi[i]; |
95 | if (!cfi) |
96 | continue; |
97 | /* errors are reported on the original insn */ |
98 | if (init_orc_entry(&orc, cfi, insn)) |
99 | return -1; |
100 | if (!memcmp(&prev_orc, &orc, sizeof(orc))) |
101 | continue; |
102 | if (orc_list_add(orc_list: &orc_list, orc: &orc, sec: insn->sec, |
103 | offset: insn->offset + i)) |
104 | return -1; |
105 | nr++; |
106 | prev_orc = orc; |
107 | empty = false; |
108 | } |
109 | |
110 | /* Skip to the end of the alt_group */ |
111 | insn = alt_group->last_insn; |
112 | } |
113 | |
114 | /* Add a section terminator */ |
115 | if (!empty) { |
116 | orc_list_add(orc_list: &orc_list, orc: &null, sec, offset: sec->sh.sh_size); |
117 | nr++; |
118 | } |
119 | } |
120 | if (!nr) |
121 | return 0; |
122 | |
123 | /* Create .orc_unwind, .orc_unwind_ip and .rela.orc_unwind_ip sections: */ |
124 | sec = find_section_by_name(file->elf, ".orc_unwind" ); |
125 | if (sec) { |
126 | WARN("file already has .orc_unwind section, skipping" ); |
127 | return -1; |
128 | } |
129 | orc_sec = elf_create_section(file->elf, ".orc_unwind" , |
130 | sizeof(struct orc_entry), nr); |
131 | if (!orc_sec) |
132 | return -1; |
133 | |
134 | sec = elf_create_section_pair(file->elf, ".orc_unwind_ip" , sizeof(int), nr, nr); |
135 | if (!sec) |
136 | return -1; |
137 | |
138 | /* Write ORC entries to sections: */ |
139 | list_for_each_entry(entry, &orc_list, list) { |
140 | if (write_orc_entry(file->elf, orc_sec, sec, idx++, |
141 | entry->insn_sec, entry->insn_off, |
142 | &entry->orc)) |
143 | return -1; |
144 | } |
145 | |
146 | return 0; |
147 | } |
148 | |