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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
17struct 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
24static 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
42static 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
49int 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, sec,
78 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, insn->sec,
103 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, &null, sec, 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}
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 "orc.h"
10#include "check.h"
11#include "warn.h"
12
13int create_orc(struct objtool_file *file)
14{
15 struct instruction *insn;
16
17 for_each_insn(file, insn) {
18 struct orc_entry *orc = &insn->orc;
19 struct cfi_reg *cfa = &insn->state.cfa;
20 struct cfi_reg *bp = &insn->state.regs[CFI_BP];
21
22 orc->end = insn->state.end;
23
24 if (cfa->base == CFI_UNDEFINED) {
25 orc->sp_reg = ORC_REG_UNDEFINED;
26 continue;
27 }
28
29 switch (cfa->base) {
30 case CFI_SP:
31 orc->sp_reg = ORC_REG_SP;
32 break;
33 case CFI_SP_INDIRECT:
34 orc->sp_reg = ORC_REG_SP_INDIRECT;
35 break;
36 case CFI_BP:
37 orc->sp_reg = ORC_REG_BP;
38 break;
39 case CFI_BP_INDIRECT:
40 orc->sp_reg = ORC_REG_BP_INDIRECT;
41 break;
42 case CFI_R10:
43 orc->sp_reg = ORC_REG_R10;
44 break;
45 case CFI_R13:
46 orc->sp_reg = ORC_REG_R13;
47 break;
48 case CFI_DI:
49 orc->sp_reg = ORC_REG_DI;
50 break;
51 case CFI_DX:
52 orc->sp_reg = ORC_REG_DX;
53 break;
54 default:
55 WARN_FUNC("unknown CFA base reg %d",
56 insn->sec, insn->offset, cfa->base);
57 return -1;
58 }
59
60 switch(bp->base) {
61 case CFI_UNDEFINED:
62 orc->bp_reg = ORC_REG_UNDEFINED;
63 break;
64 case CFI_CFA:
65 orc->bp_reg = ORC_REG_PREV_SP;
66 break;
67 case CFI_BP:
68 orc->bp_reg = ORC_REG_BP;
69 break;
70 default:
71 WARN_FUNC("unknown BP base reg %d",
72 insn->sec, insn->offset, bp->base);
73 return -1;
74 }
75
76 orc->sp_offset = cfa->offset;
77 orc->bp_offset = bp->offset;
78 orc->type = insn->state.type;
79 }
80
81 return 0;
82}
83
84static int create_orc_entry(struct section *u_sec, struct section *ip_relasec,
85 unsigned int idx, struct section *insn_sec,
86 unsigned long insn_off, struct orc_entry *o)
87{
88 struct orc_entry *orc;
89 struct rela *rela;
90
91 if (!insn_sec->sym) {
92 WARN("missing symbol for section %s", insn_sec->name);
93 return -1;
94 }
95
96 /* populate ORC data */
97 orc = (struct orc_entry *)u_sec->data->d_buf + idx;
98 memcpy(orc, o, sizeof(*orc));
99
100 /* populate rela for ip */
101 rela = malloc(sizeof(*rela));
102 if (!rela) {
103 perror("malloc");
104 return -1;
105 }
106 memset(rela, 0, sizeof(*rela));
107
108 rela->sym = insn_sec->sym;
109 rela->addend = insn_off;
110 rela->type = R_X86_64_PC32;
111 rela->offset = idx * sizeof(int);
112
113 list_add_tail(&rela->list, &ip_relasec->rela_list);
114 hash_add(ip_relasec->rela_hash, &rela->hash, rela->offset);
115
116 return 0;
117}
118
119int create_orc_sections(struct objtool_file *file)
120{
121 struct instruction *insn, *prev_insn;
122 struct section *sec, *u_sec, *ip_relasec;
123 unsigned int idx;
124
125 struct orc_entry empty = {
126 .sp_reg = ORC_REG_UNDEFINED,
127 .bp_reg = ORC_REG_UNDEFINED,
128 .type = ORC_TYPE_CALL,
129 };
130
131 sec = find_section_by_name(file->elf, ".orc_unwind");
132 if (sec) {
133 WARN("file already has .orc_unwind section, skipping");
134 return -1;
135 }
136
137 /* count the number of needed orcs */
138 idx = 0;
139 for_each_sec(file, sec) {
140 if (!sec->text)
141 continue;
142
143 prev_insn = NULL;
144 sec_for_each_insn(file, sec, insn) {
145 if (!prev_insn ||
146 memcmp(&insn->orc, &prev_insn->orc,
147 sizeof(struct orc_entry))) {
148 idx++;
149 }
150 prev_insn = insn;
151 }
152
153 /* section terminator */
154 if (prev_insn)
155 idx++;
156 }
157 if (!idx)
158 return -1;
159
160
161 /* create .orc_unwind_ip and .rela.orc_unwind_ip sections */
162 sec = elf_create_section(file->elf, ".orc_unwind_ip", sizeof(int), idx);
163 if (!sec)
164 return -1;
165
166 ip_relasec = elf_create_rela_section(file->elf, sec);
167 if (!ip_relasec)
168 return -1;
169
170 /* create .orc_unwind section */
171 u_sec = elf_create_section(file->elf, ".orc_unwind",
172 sizeof(struct orc_entry), idx);
173
174 /* populate sections */
175 idx = 0;
176 for_each_sec(file, sec) {
177 if (!sec->text)
178 continue;
179
180 prev_insn = NULL;
181 sec_for_each_insn(file, sec, insn) {
182 if (!prev_insn || memcmp(&insn->orc, &prev_insn->orc,
183 sizeof(struct orc_entry))) {
184
185 if (create_orc_entry(u_sec, ip_relasec, idx,
186 insn->sec, insn->offset,
187 &insn->orc))
188 return -1;
189
190 idx++;
191 }
192 prev_insn = insn;
193 }
194
195 /* section terminator */
196 if (prev_insn) {
197 if (create_orc_entry(u_sec, ip_relasec, idx,
198 prev_insn->sec,
199 prev_insn->offset + prev_insn->len,
200 &empty))
201 return -1;
202
203 idx++;
204 }
205 }
206
207 if (elf_rebuild_rela_section(ip_relasec))
208 return -1;
209
210 return 0;
211}