1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * Copyright (C) 2017 Josh Poimboeuf <jpoimboe@redhat.com>
13 int create_orc(struct objtool_file *file)
15 struct instruction *insn;
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];
22 orc->end = insn->state.end;
24 if (cfa->base == CFI_UNDEFINED) {
25 orc->sp_reg = ORC_REG_UNDEFINED;
31 orc->sp_reg = ORC_REG_SP;
34 orc->sp_reg = ORC_REG_SP_INDIRECT;
37 orc->sp_reg = ORC_REG_BP;
40 orc->sp_reg = ORC_REG_BP_INDIRECT;
43 orc->sp_reg = ORC_REG_R10;
46 orc->sp_reg = ORC_REG_R13;
49 orc->sp_reg = ORC_REG_DI;
52 orc->sp_reg = ORC_REG_DX;
55 WARN_FUNC("unknown CFA base reg %d",
56 insn->sec, insn->offset, cfa->base);
62 orc->bp_reg = ORC_REG_UNDEFINED;
65 orc->bp_reg = ORC_REG_PREV_SP;
68 orc->bp_reg = ORC_REG_BP;
71 WARN_FUNC("unknown BP base reg %d",
72 insn->sec, insn->offset, bp->base);
76 orc->sp_offset = cfa->offset;
77 orc->bp_offset = bp->offset;
78 orc->type = insn->state.type;
84 static int create_orc_entry(struct elf *elf, 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)
88 struct orc_entry *orc;
91 /* populate ORC data */
92 orc = (struct orc_entry *)u_sec->data->d_buf + idx;
93 memcpy(orc, o, sizeof(*orc));
95 /* populate rela for ip */
96 rela = malloc(sizeof(*rela));
101 memset(rela, 0, sizeof(*rela));
104 rela->sym = insn_sec->sym;
105 rela->addend = insn_off;
108 * The Clang assembler doesn't produce section symbols, so we
109 * have to reference the function symbol instead:
111 rela->sym = find_symbol_containing(insn_sec, insn_off);
114 * Hack alert. This happens when we need to reference
115 * the NOP pad insn immediately after the function.
117 rela->sym = find_symbol_containing(insn_sec,
121 WARN("missing symbol for insn at offset 0x%lx\n",
126 rela->addend = insn_off - rela->sym->offset;
129 rela->type = R_X86_64_PC32;
130 rela->offset = idx * sizeof(int);
131 rela->sec = ip_relasec;
133 list_add_tail(&rela->list, &ip_relasec->rela_list);
134 hash_add(elf->rela_hash, &rela->hash, rela_hash(rela));
139 int create_orc_sections(struct objtool_file *file)
141 struct instruction *insn, *prev_insn;
142 struct section *sec, *u_sec, *ip_relasec;
145 struct orc_entry empty = {
146 .sp_reg = ORC_REG_UNDEFINED,
147 .bp_reg = ORC_REG_UNDEFINED,
148 .type = ORC_TYPE_CALL,
151 sec = find_section_by_name(file->elf, ".orc_unwind");
153 WARN("file already has .orc_unwind section, skipping");
157 /* count the number of needed orcs */
159 for_each_sec(file, sec) {
164 sec_for_each_insn(file, sec, insn) {
166 memcmp(&insn->orc, &prev_insn->orc,
167 sizeof(struct orc_entry))) {
173 /* section terminator */
181 /* create .orc_unwind_ip and .rela.orc_unwind_ip sections */
182 sec = elf_create_section(file->elf, ".orc_unwind_ip", sizeof(int), idx);
186 ip_relasec = elf_create_rela_section(file->elf, sec);
190 /* create .orc_unwind section */
191 u_sec = elf_create_section(file->elf, ".orc_unwind",
192 sizeof(struct orc_entry), idx);
194 /* populate sections */
196 for_each_sec(file, sec) {
201 sec_for_each_insn(file, sec, insn) {
202 if (!prev_insn || memcmp(&insn->orc, &prev_insn->orc,
203 sizeof(struct orc_entry))) {
205 if (create_orc_entry(file->elf, u_sec, ip_relasec, idx,
206 insn->sec, insn->offset,
215 /* section terminator */
217 if (create_orc_entry(file->elf, u_sec, ip_relasec, idx,
219 prev_insn->offset + prev_insn->len,
227 if (elf_rebuild_rela_section(ip_relasec))