1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
|
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2017 Josh Poimboeuf <jpoimboe@redhat.com>
*/
#include <stdlib.h>
#include <string.h>
#include <linux/objtool.h>
#include <asm/orc_types.h>
#include "check.h"
#include "warn.h"
int create_orc(struct objtool_file *file)
{
struct instruction *insn;
for_each_insn(file, insn) {
struct orc_entry *orc = &insn->orc;
struct cfi_reg *cfa = &insn->cfi.cfa;
struct cfi_reg *bp = &insn->cfi.regs[CFI_BP];
if (!insn->sec->text)
continue;
orc->end = insn->cfi.end;
if (cfa->base == CFI_UNDEFINED) {
orc->sp_reg = ORC_REG_UNDEFINED;
continue;
}
switch (cfa->base) {
case CFI_SP:
orc->sp_reg = ORC_REG_SP;
break;
case CFI_SP_INDIRECT:
orc->sp_reg = ORC_REG_SP_INDIRECT;
break;
case CFI_BP:
orc->sp_reg = ORC_REG_BP;
break;
case CFI_BP_INDIRECT:
orc->sp_reg = ORC_REG_BP_INDIRECT;
break;
case CFI_R10:
orc->sp_reg = ORC_REG_R10;
break;
case CFI_R13:
orc->sp_reg = ORC_REG_R13;
break;
case CFI_DI:
orc->sp_reg = ORC_REG_DI;
break;
case CFI_DX:
orc->sp_reg = ORC_REG_DX;
break;
default:
WARN_FUNC("unknown CFA base reg %d",
insn->sec, insn->offset, cfa->base);
return -1;
}
switch(bp->base) {
case CFI_UNDEFINED:
orc->bp_reg = ORC_REG_UNDEFINED;
break;
case CFI_CFA:
orc->bp_reg = ORC_REG_PREV_SP;
break;
case CFI_BP:
orc->bp_reg = ORC_REG_BP;
break;
default:
WARN_FUNC("unknown BP base reg %d",
insn->sec, insn->offset, bp->base);
return -1;
}
orc->sp_offset = cfa->offset;
orc->bp_offset = bp->offset;
orc->type = insn->cfi.type;
}
return 0;
}
static int create_orc_entry(struct elf *elf, struct section *u_sec, struct section *ip_relocsec,
unsigned int idx, struct section *insn_sec,
unsigned long insn_off, struct orc_entry *o)
{
struct orc_entry *orc;
struct reloc *reloc;
/* populate ORC data */
orc = (struct orc_entry *)u_sec->data->d_buf + idx;
memcpy(orc, o, sizeof(*orc));
/* populate reloc for ip */
reloc = malloc(sizeof(*reloc));
if (!reloc) {
perror("malloc");
return -1;
}
memset(reloc, 0, sizeof(*reloc));
insn_to_reloc_sym_addend(insn_sec, insn_off, reloc);
if (!reloc->sym) {
WARN("missing symbol for insn at offset 0x%lx",
insn_off);
return -1;
}
reloc->type = R_X86_64_PC32;
reloc->offset = idx * sizeof(int);
reloc->sec = ip_relocsec;
elf_add_reloc(elf, reloc);
return 0;
}
int create_orc_sections(struct objtool_file *file)
{
struct instruction *insn, *prev_insn;
struct section *sec, *u_sec, *ip_relocsec;
unsigned int idx;
struct orc_entry empty = {
.sp_reg = ORC_REG_UNDEFINED,
.bp_reg = ORC_REG_UNDEFINED,
.type = UNWIND_HINT_TYPE_CALL,
};
sec = find_section_by_name(file->elf, ".orc_unwind");
if (sec) {
WARN("file already has .orc_unwind section, skipping");
return -1;
}
/* count the number of needed orcs */
idx = 0;
for_each_sec(file, sec) {
if (!sec->text)
continue;
prev_insn = NULL;
sec_for_each_insn(file, sec, insn) {
if (!prev_insn ||
memcmp(&insn->orc, &prev_insn->orc,
sizeof(struct orc_entry))) {
idx++;
}
prev_insn = insn;
}
/* section terminator */
if (prev_insn)
idx++;
}
if (!idx)
return -1;
/* create .orc_unwind_ip and .rela.orc_unwind_ip sections */
sec = elf_create_section(file->elf, ".orc_unwind_ip", 0, sizeof(int), idx);
if (!sec)
return -1;
ip_relocsec = elf_create_reloc_section(file->elf, sec, SHT_RELA);
if (!ip_relocsec)
return -1;
/* create .orc_unwind section */
u_sec = elf_create_section(file->elf, ".orc_unwind", 0,
sizeof(struct orc_entry), idx);
/* populate sections */
idx = 0;
for_each_sec(file, sec) {
if (!sec->text)
continue;
prev_insn = NULL;
sec_for_each_insn(file, sec, insn) {
if (!prev_insn || memcmp(&insn->orc, &prev_insn->orc,
sizeof(struct orc_entry))) {
if (create_orc_entry(file->elf, u_sec, ip_relocsec, idx,
insn->sec, insn->offset,
&insn->orc))
return -1;
idx++;
}
prev_insn = insn;
}
/* section terminator */
if (prev_insn) {
if (create_orc_entry(file->elf, u_sec, ip_relocsec, idx,
prev_insn->sec,
prev_insn->offset + prev_insn->len,
&empty))
return -1;
idx++;
}
}
if (elf_rebuild_reloc_section(file->elf, ip_relocsec))
return -1;
return 0;
}
|
