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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.h>
10#include <asm/orc_types.h>
11
12#include <objtool/check.h>
13#include <objtool/warn.h>
14#include <objtool/endianness.h>
15
16static int init_orc_entry(struct orc_entry *orc, struct cfi_state *cfi,
17 struct instruction *insn)
18{
19 struct cfi_reg *bp = &cfi->regs[CFI_BP];
20
21 memset(orc, 0, sizeof(*orc));
22
23 if (!cfi) {
24 orc->end = 0;
25 orc->sp_reg = ORC_REG_UNDEFINED;
26 return 0;
27 }
28
29 orc->end = cfi->end;
30
31 if (cfi->cfa.base == CFI_UNDEFINED) {
32 orc->sp_reg = ORC_REG_UNDEFINED;
33 return 0;
34 }
35
36 switch (cfi->cfa.base) {
37 case CFI_SP:
38 orc->sp_reg = ORC_REG_SP;
39 break;
40 case CFI_SP_INDIRECT:
41 orc->sp_reg = ORC_REG_SP_INDIRECT;
42 break;
43 case CFI_BP:
44 orc->sp_reg = ORC_REG_BP;
45 break;
46 case CFI_BP_INDIRECT:
47 orc->sp_reg = ORC_REG_BP_INDIRECT;
48 break;
49 case CFI_R10:
50 orc->sp_reg = ORC_REG_R10;
51 break;
52 case CFI_R13:
53 orc->sp_reg = ORC_REG_R13;
54 break;
55 case CFI_DI:
56 orc->sp_reg = ORC_REG_DI;
57 break;
58 case CFI_DX:
59 orc->sp_reg = ORC_REG_DX;
60 break;
61 default:
62 WARN_FUNC("unknown CFA base reg %d",
63 insn->sec, insn->offset, cfi->cfa.base);
64 return -1;
65 }
66
67 switch (bp->base) {
68 case CFI_UNDEFINED:
69 orc->bp_reg = ORC_REG_UNDEFINED;
70 break;
71 case CFI_CFA:
72 orc->bp_reg = ORC_REG_PREV_SP;
73 break;
74 case CFI_BP:
75 orc->bp_reg = ORC_REG_BP;
76 break;
77 default:
78 WARN_FUNC("unknown BP base reg %d",
79 insn->sec, insn->offset, bp->base);
80 return -1;
81 }
82
83 orc->sp_offset = cfi->cfa.offset;
84 orc->bp_offset = bp->offset;
85 orc->type = cfi->type;
86
87 return 0;
88}
89
90static int write_orc_entry(struct elf *elf, struct section *orc_sec,
91 struct section *ip_sec, unsigned int idx,
92 struct section *insn_sec, unsigned long insn_off,
93 struct orc_entry *o)
94{
95 struct orc_entry *orc;
96
97 /* populate ORC data */
98 orc = (struct orc_entry *)orc_sec->data->d_buf + idx;
99 memcpy(orc, o, sizeof(*orc));
100 orc->sp_offset = bswap_if_needed(elf, orc->sp_offset);
101 orc->bp_offset = bswap_if_needed(elf, orc->bp_offset);
102
103 /* populate reloc for ip */
104 if (elf_add_reloc_to_insn(elf, ip_sec, idx * sizeof(int), R_X86_64_PC32,
105 insn_sec, insn_off))
106 return -1;
107
108 return 0;
109}
110
111struct orc_list_entry {
112 struct list_head list;
113 struct orc_entry orc;
114 struct section *insn_sec;
115 unsigned long insn_off;
116};
117
118static int orc_list_add(struct list_head *orc_list, struct orc_entry *orc,
119 struct section *sec, unsigned long offset)
120{
121 struct orc_list_entry *entry = malloc(sizeof(*entry));
122
123 if (!entry) {
124 WARN("malloc failed");
125 return -1;
126 }
127
128 entry->orc = *orc;
129 entry->insn_sec = sec;
130 entry->insn_off = offset;
131
132 list_add_tail(&entry->list, orc_list);
133 return 0;
134}
135
136static unsigned long alt_group_len(struct alt_group *alt_group)
137{
138 return alt_group->last_insn->offset +
139 alt_group->last_insn->len -
140 alt_group->first_insn->offset;
141}
142
143int orc_create(struct objtool_file *file)
144{
145 struct section *sec, *orc_sec;
146 unsigned int nr = 0, idx = 0;
147 struct orc_list_entry *entry;
148 struct list_head orc_list;
149
150 struct orc_entry null = {
151 .sp_reg = ORC_REG_UNDEFINED,
152 .bp_reg = ORC_REG_UNDEFINED,
153 .type = UNWIND_HINT_TYPE_CALL,
154 };
155
156 /* Build a deduplicated list of ORC entries: */
157 INIT_LIST_HEAD(&orc_list);
158 for_each_sec(file, sec) {
159 struct orc_entry orc, prev_orc = {0};
160 struct instruction *insn;
161 bool empty = true;
162
163 if (!sec->text)
164 continue;
165
166 sec_for_each_insn(file, sec, insn) {
167 struct alt_group *alt_group = insn->alt_group;
168 int i;
169
170 if (!alt_group) {
171 if (init_orc_entry(&orc, insn->cfi, insn))
172 return -1;
173 if (!memcmp(&prev_orc, &orc, sizeof(orc)))
174 continue;
175 if (orc_list_add(&orc_list, &orc, sec,
176 insn->offset))
177 return -1;
178 nr++;
179 prev_orc = orc;
180 empty = false;
181 continue;
182 }
183
184 /*
185 * Alternatives can have different stack layout
186 * possibilities (but they shouldn't conflict).
187 * Instead of traversing the instructions, use the
188 * alt_group's flattened byte-offset-addressed CFI
189 * array.
190 */
191 for (i = 0; i < alt_group_len(alt_group); i++) {
192 struct cfi_state *cfi = alt_group->cfi[i];
193 if (!cfi)
194 continue;
195 /* errors are reported on the original insn */
196 if (init_orc_entry(&orc, cfi, insn))
197 return -1;
198 if (!memcmp(&prev_orc, &orc, sizeof(orc)))
199 continue;
200 if (orc_list_add(&orc_list, &orc, insn->sec,
201 insn->offset + i))
202 return -1;
203 nr++;
204 prev_orc = orc;
205 empty = false;
206 }
207
208 /* Skip to the end of the alt_group */
209 insn = alt_group->last_insn;
210 }
211
212 /* Add a section terminator */
213 if (!empty) {
214 orc_list_add(&orc_list, &null, sec, sec->sh.sh_size);
215 nr++;
216 }
217 }
218 if (!nr)
219 return 0;
220
221 /* Create .orc_unwind, .orc_unwind_ip and .rela.orc_unwind_ip sections: */
222 sec = find_section_by_name(file->elf, ".orc_unwind");
223 if (sec) {
224 WARN("file already has .orc_unwind section, skipping");
225 return -1;
226 }
227 orc_sec = elf_create_section(file->elf, ".orc_unwind", 0,
228 sizeof(struct orc_entry), nr);
229 if (!orc_sec)
230 return -1;
231
232 sec = elf_create_section(file->elf, ".orc_unwind_ip", 0, sizeof(int), nr);
233 if (!sec)
234 return -1;
235
236 /* Write ORC entries to sections: */
237 list_for_each_entry(entry, &orc_list, list) {
238 if (write_orc_entry(file->elf, orc_sec, sec, idx++,
239 entry->insn_sec, entry->insn_off,
240 &entry->orc))
241 return -1;
242 }
243
244 return 0;
245}
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/warn.h>
14#include <objtool/endianness.h>
15
16static int init_orc_entry(struct orc_entry *orc, struct cfi_state *cfi,
17 struct instruction *insn)
18{
19 struct cfi_reg *bp = &cfi->regs[CFI_BP];
20
21 memset(orc, 0, sizeof(*orc));
22
23 if (!cfi) {
24 /*
25 * This is usually either unreachable nops/traps (which don't
26 * trigger unreachable instruction warnings), or
27 * STACK_FRAME_NON_STANDARD functions.
28 */
29 orc->type = ORC_TYPE_UNDEFINED;
30 return 0;
31 }
32
33 switch (cfi->type) {
34 case UNWIND_HINT_TYPE_UNDEFINED:
35 orc->type = ORC_TYPE_UNDEFINED;
36 return 0;
37 case UNWIND_HINT_TYPE_END_OF_STACK:
38 orc->type = ORC_TYPE_END_OF_STACK;
39 return 0;
40 case UNWIND_HINT_TYPE_CALL:
41 orc->type = ORC_TYPE_CALL;
42 break;
43 case UNWIND_HINT_TYPE_REGS:
44 orc->type = ORC_TYPE_REGS;
45 break;
46 case UNWIND_HINT_TYPE_REGS_PARTIAL:
47 orc->type = ORC_TYPE_REGS_PARTIAL;
48 break;
49 default:
50 WARN_INSN(insn, "unknown unwind hint type %d", cfi->type);
51 return -1;
52 }
53
54 orc->signal = cfi->signal;
55
56 switch (cfi->cfa.base) {
57 case CFI_SP:
58 orc->sp_reg = ORC_REG_SP;
59 break;
60 case CFI_SP_INDIRECT:
61 orc->sp_reg = ORC_REG_SP_INDIRECT;
62 break;
63 case CFI_BP:
64 orc->sp_reg = ORC_REG_BP;
65 break;
66 case CFI_BP_INDIRECT:
67 orc->sp_reg = ORC_REG_BP_INDIRECT;
68 break;
69 case CFI_R10:
70 orc->sp_reg = ORC_REG_R10;
71 break;
72 case CFI_R13:
73 orc->sp_reg = ORC_REG_R13;
74 break;
75 case CFI_DI:
76 orc->sp_reg = ORC_REG_DI;
77 break;
78 case CFI_DX:
79 orc->sp_reg = ORC_REG_DX;
80 break;
81 default:
82 WARN_INSN(insn, "unknown CFA base reg %d", cfi->cfa.base);
83 return -1;
84 }
85
86 switch (bp->base) {
87 case CFI_UNDEFINED:
88 orc->bp_reg = ORC_REG_UNDEFINED;
89 break;
90 case CFI_CFA:
91 orc->bp_reg = ORC_REG_PREV_SP;
92 break;
93 case CFI_BP:
94 orc->bp_reg = ORC_REG_BP;
95 break;
96 default:
97 WARN_INSN(insn, "unknown BP base reg %d", bp->base);
98 return -1;
99 }
100
101 orc->sp_offset = cfi->cfa.offset;
102 orc->bp_offset = bp->offset;
103
104 return 0;
105}
106
107static int write_orc_entry(struct elf *elf, struct section *orc_sec,
108 struct section *ip_sec, unsigned int idx,
109 struct section *insn_sec, unsigned long insn_off,
110 struct orc_entry *o)
111{
112 struct orc_entry *orc;
113
114 /* populate ORC data */
115 orc = (struct orc_entry *)orc_sec->data->d_buf + idx;
116 memcpy(orc, o, sizeof(*orc));
117 orc->sp_offset = bswap_if_needed(elf, orc->sp_offset);
118 orc->bp_offset = bswap_if_needed(elf, orc->bp_offset);
119
120 /* populate reloc for ip */
121 if (!elf_init_reloc_text_sym(elf, ip_sec, idx * sizeof(int), idx,
122 insn_sec, insn_off))
123 return -1;
124
125 return 0;
126}
127
128struct orc_list_entry {
129 struct list_head list;
130 struct orc_entry orc;
131 struct section *insn_sec;
132 unsigned long insn_off;
133};
134
135static int orc_list_add(struct list_head *orc_list, struct orc_entry *orc,
136 struct section *sec, unsigned long offset)
137{
138 struct orc_list_entry *entry = malloc(sizeof(*entry));
139
140 if (!entry) {
141 WARN("malloc failed");
142 return -1;
143 }
144
145 entry->orc = *orc;
146 entry->insn_sec = sec;
147 entry->insn_off = offset;
148
149 list_add_tail(&entry->list, orc_list);
150 return 0;
151}
152
153static unsigned long alt_group_len(struct alt_group *alt_group)
154{
155 return alt_group->last_insn->offset +
156 alt_group->last_insn->len -
157 alt_group->first_insn->offset;
158}
159
160int orc_create(struct objtool_file *file)
161{
162 struct section *sec, *orc_sec;
163 unsigned int nr = 0, idx = 0;
164 struct orc_list_entry *entry;
165 struct list_head orc_list;
166
167 struct orc_entry null = { .type = ORC_TYPE_UNDEFINED };
168
169 /* Build a deduplicated list of ORC entries: */
170 INIT_LIST_HEAD(&orc_list);
171 for_each_sec(file, sec) {
172 struct orc_entry orc, prev_orc = {0};
173 struct instruction *insn;
174 bool empty = true;
175
176 if (!sec->text)
177 continue;
178
179 sec_for_each_insn(file, sec, insn) {
180 struct alt_group *alt_group = insn->alt_group;
181 int i;
182
183 if (!alt_group) {
184 if (init_orc_entry(&orc, insn->cfi, insn))
185 return -1;
186 if (!memcmp(&prev_orc, &orc, sizeof(orc)))
187 continue;
188 if (orc_list_add(&orc_list, &orc, sec,
189 insn->offset))
190 return -1;
191 nr++;
192 prev_orc = orc;
193 empty = false;
194 continue;
195 }
196
197 /*
198 * Alternatives can have different stack layout
199 * possibilities (but they shouldn't conflict).
200 * Instead of traversing the instructions, use the
201 * alt_group's flattened byte-offset-addressed CFI
202 * array.
203 */
204 for (i = 0; i < alt_group_len(alt_group); i++) {
205 struct cfi_state *cfi = alt_group->cfi[i];
206 if (!cfi)
207 continue;
208 /* errors are reported on the original insn */
209 if (init_orc_entry(&orc, cfi, insn))
210 return -1;
211 if (!memcmp(&prev_orc, &orc, sizeof(orc)))
212 continue;
213 if (orc_list_add(&orc_list, &orc, insn->sec,
214 insn->offset + i))
215 return -1;
216 nr++;
217 prev_orc = orc;
218 empty = false;
219 }
220
221 /* Skip to the end of the alt_group */
222 insn = alt_group->last_insn;
223 }
224
225 /* Add a section terminator */
226 if (!empty) {
227 orc_list_add(&orc_list, &null, sec, sec->sh.sh_size);
228 nr++;
229 }
230 }
231 if (!nr)
232 return 0;
233
234 /* Create .orc_unwind, .orc_unwind_ip and .rela.orc_unwind_ip sections: */
235 sec = find_section_by_name(file->elf, ".orc_unwind");
236 if (sec) {
237 WARN("file already has .orc_unwind section, skipping");
238 return -1;
239 }
240 orc_sec = elf_create_section(file->elf, ".orc_unwind",
241 sizeof(struct orc_entry), nr);
242 if (!orc_sec)
243 return -1;
244
245 sec = elf_create_section_pair(file->elf, ".orc_unwind_ip", sizeof(int), nr, nr);
246 if (!sec)
247 return -1;
248
249 /* Write ORC entries to sections: */
250 list_for_each_entry(entry, &orc_list, list) {
251 if (write_orc_entry(file->elf, orc_sec, sec, idx++,
252 entry->insn_sec, entry->insn_off,
253 &entry->orc))
254 return -1;
255 }
256
257 return 0;
258}