Thomas Gleixner | 1ccea77 | 2019-05-19 15:51:43 +0200 | [diff] [blame] | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
Josh Poimboeuf | 627fce1 | 2017-07-11 10:33:42 -0500 | [diff] [blame] | 2 | /* |
| 3 | * Copyright (C) 2017 Josh Poimboeuf <jpoimboe@redhat.com> |
Josh Poimboeuf | 627fce1 | 2017-07-11 10:33:42 -0500 | [diff] [blame] | 4 | */ |
| 5 | |
| 6 | #include <stdlib.h> |
| 7 | #include <string.h> |
| 8 | |
Josh Poimboeuf | 627fce1 | 2017-07-11 10:33:42 -0500 | [diff] [blame] | 9 | #include "check.h" |
| 10 | #include "warn.h" |
| 11 | |
| 12 | int create_orc(struct objtool_file *file) |
| 13 | { |
| 14 | struct instruction *insn; |
| 15 | |
| 16 | for_each_insn(file, insn) { |
| 17 | struct orc_entry *orc = &insn->orc; |
Peter Zijlstra | e7c0219 | 2020-03-25 14:04:45 +0100 | [diff] [blame] | 18 | struct cfi_reg *cfa = &insn->cfi.cfa; |
| 19 | struct cfi_reg *bp = &insn->cfi.regs[CFI_BP]; |
Josh Poimboeuf | 627fce1 | 2017-07-11 10:33:42 -0500 | [diff] [blame] | 20 | |
Peter Zijlstra | e7c0219 | 2020-03-25 14:04:45 +0100 | [diff] [blame] | 21 | orc->end = insn->cfi.end; |
Josh Poimboeuf | d31a580 | 2018-05-18 08:47:12 +0200 | [diff] [blame] | 22 | |
Josh Poimboeuf | 627fce1 | 2017-07-11 10:33:42 -0500 | [diff] [blame] | 23 | if (cfa->base == CFI_UNDEFINED) { |
| 24 | orc->sp_reg = ORC_REG_UNDEFINED; |
| 25 | continue; |
| 26 | } |
| 27 | |
| 28 | switch (cfa->base) { |
| 29 | case CFI_SP: |
| 30 | orc->sp_reg = ORC_REG_SP; |
| 31 | break; |
| 32 | case CFI_SP_INDIRECT: |
| 33 | orc->sp_reg = ORC_REG_SP_INDIRECT; |
| 34 | break; |
| 35 | case CFI_BP: |
| 36 | orc->sp_reg = ORC_REG_BP; |
| 37 | break; |
| 38 | case CFI_BP_INDIRECT: |
| 39 | orc->sp_reg = ORC_REG_BP_INDIRECT; |
| 40 | break; |
| 41 | case CFI_R10: |
| 42 | orc->sp_reg = ORC_REG_R10; |
| 43 | break; |
| 44 | case CFI_R13: |
| 45 | orc->sp_reg = ORC_REG_R13; |
| 46 | break; |
| 47 | case CFI_DI: |
| 48 | orc->sp_reg = ORC_REG_DI; |
| 49 | break; |
| 50 | case CFI_DX: |
| 51 | orc->sp_reg = ORC_REG_DX; |
| 52 | break; |
| 53 | default: |
| 54 | WARN_FUNC("unknown CFA base reg %d", |
| 55 | insn->sec, insn->offset, cfa->base); |
| 56 | return -1; |
| 57 | } |
| 58 | |
| 59 | switch(bp->base) { |
| 60 | case CFI_UNDEFINED: |
| 61 | orc->bp_reg = ORC_REG_UNDEFINED; |
| 62 | break; |
| 63 | case CFI_CFA: |
| 64 | orc->bp_reg = ORC_REG_PREV_SP; |
| 65 | break; |
| 66 | case CFI_BP: |
| 67 | orc->bp_reg = ORC_REG_BP; |
| 68 | break; |
| 69 | default: |
| 70 | WARN_FUNC("unknown BP base reg %d", |
| 71 | insn->sec, insn->offset, bp->base); |
| 72 | return -1; |
| 73 | } |
| 74 | |
| 75 | orc->sp_offset = cfa->offset; |
| 76 | orc->bp_offset = bp->offset; |
Peter Zijlstra | e7c0219 | 2020-03-25 14:04:45 +0100 | [diff] [blame] | 77 | orc->type = insn->cfi.type; |
Josh Poimboeuf | 627fce1 | 2017-07-11 10:33:42 -0500 | [diff] [blame] | 78 | } |
| 79 | |
| 80 | return 0; |
| 81 | } |
| 82 | |
Peter Zijlstra | 8b5fa6b | 2020-03-12 11:23:36 +0100 | [diff] [blame] | 83 | static int create_orc_entry(struct elf *elf, struct section *u_sec, struct section *ip_relasec, |
Josh Poimboeuf | 627fce1 | 2017-07-11 10:33:42 -0500 | [diff] [blame] | 84 | unsigned int idx, struct section *insn_sec, |
| 85 | unsigned long insn_off, struct orc_entry *o) |
| 86 | { |
| 87 | struct orc_entry *orc; |
| 88 | struct rela *rela; |
| 89 | |
| 90 | /* populate ORC data */ |
| 91 | orc = (struct orc_entry *)u_sec->data->d_buf + idx; |
| 92 | memcpy(orc, o, sizeof(*orc)); |
| 93 | |
| 94 | /* populate rela for ip */ |
| 95 | rela = malloc(sizeof(*rela)); |
| 96 | if (!rela) { |
| 97 | perror("malloc"); |
| 98 | return -1; |
| 99 | } |
| 100 | memset(rela, 0, sizeof(*rela)); |
| 101 | |
Josh Poimboeuf | e81e072 | 2020-04-01 13:23:27 -0500 | [diff] [blame] | 102 | if (insn_sec->sym) { |
| 103 | rela->sym = insn_sec->sym; |
| 104 | rela->addend = insn_off; |
| 105 | } else { |
| 106 | /* |
| 107 | * The Clang assembler doesn't produce section symbols, so we |
| 108 | * have to reference the function symbol instead: |
| 109 | */ |
| 110 | rela->sym = find_symbol_containing(insn_sec, insn_off); |
| 111 | if (!rela->sym) { |
| 112 | /* |
| 113 | * Hack alert. This happens when we need to reference |
| 114 | * the NOP pad insn immediately after the function. |
| 115 | */ |
| 116 | rela->sym = find_symbol_containing(insn_sec, |
| 117 | insn_off - 1); |
| 118 | } |
| 119 | if (!rela->sym) { |
| 120 | WARN("missing symbol for insn at offset 0x%lx\n", |
| 121 | insn_off); |
| 122 | return -1; |
| 123 | } |
| 124 | |
| 125 | rela->addend = insn_off - rela->sym->offset; |
| 126 | } |
| 127 | |
Josh Poimboeuf | 627fce1 | 2017-07-11 10:33:42 -0500 | [diff] [blame] | 128 | rela->type = R_X86_64_PC32; |
| 129 | rela->offset = idx * sizeof(int); |
Peter Zijlstra | 8b5fa6b | 2020-03-12 11:23:36 +0100 | [diff] [blame] | 130 | rela->sec = ip_relasec; |
Josh Poimboeuf | 627fce1 | 2017-07-11 10:33:42 -0500 | [diff] [blame] | 131 | |
Peter Zijlstra | 34f7c96 | 2020-03-12 14:29:38 +0100 | [diff] [blame] | 132 | elf_add_rela(elf, rela); |
Josh Poimboeuf | 627fce1 | 2017-07-11 10:33:42 -0500 | [diff] [blame] | 133 | |
| 134 | return 0; |
| 135 | } |
| 136 | |
| 137 | int create_orc_sections(struct objtool_file *file) |
| 138 | { |
| 139 | struct instruction *insn, *prev_insn; |
| 140 | struct section *sec, *u_sec, *ip_relasec; |
| 141 | unsigned int idx; |
| 142 | |
| 143 | struct orc_entry empty = { |
| 144 | .sp_reg = ORC_REG_UNDEFINED, |
| 145 | .bp_reg = ORC_REG_UNDEFINED, |
| 146 | .type = ORC_TYPE_CALL, |
| 147 | }; |
| 148 | |
| 149 | sec = find_section_by_name(file->elf, ".orc_unwind"); |
| 150 | if (sec) { |
| 151 | WARN("file already has .orc_unwind section, skipping"); |
| 152 | return -1; |
| 153 | } |
| 154 | |
| 155 | /* count the number of needed orcs */ |
| 156 | idx = 0; |
| 157 | for_each_sec(file, sec) { |
| 158 | if (!sec->text) |
| 159 | continue; |
| 160 | |
| 161 | prev_insn = NULL; |
| 162 | sec_for_each_insn(file, sec, insn) { |
| 163 | if (!prev_insn || |
| 164 | memcmp(&insn->orc, &prev_insn->orc, |
| 165 | sizeof(struct orc_entry))) { |
| 166 | idx++; |
| 167 | } |
| 168 | prev_insn = insn; |
| 169 | } |
| 170 | |
| 171 | /* section terminator */ |
| 172 | if (prev_insn) |
| 173 | idx++; |
| 174 | } |
| 175 | if (!idx) |
| 176 | return -1; |
| 177 | |
| 178 | |
| 179 | /* create .orc_unwind_ip and .rela.orc_unwind_ip sections */ |
| 180 | sec = elf_create_section(file->elf, ".orc_unwind_ip", sizeof(int), idx); |
Simon Ser | ce90aaf | 2017-12-30 14:43:32 -0600 | [diff] [blame] | 181 | if (!sec) |
| 182 | return -1; |
Josh Poimboeuf | 627fce1 | 2017-07-11 10:33:42 -0500 | [diff] [blame] | 183 | |
| 184 | ip_relasec = elf_create_rela_section(file->elf, sec); |
| 185 | if (!ip_relasec) |
| 186 | return -1; |
| 187 | |
| 188 | /* create .orc_unwind section */ |
| 189 | u_sec = elf_create_section(file->elf, ".orc_unwind", |
| 190 | sizeof(struct orc_entry), idx); |
| 191 | |
| 192 | /* populate sections */ |
| 193 | idx = 0; |
| 194 | for_each_sec(file, sec) { |
| 195 | if (!sec->text) |
| 196 | continue; |
| 197 | |
| 198 | prev_insn = NULL; |
| 199 | sec_for_each_insn(file, sec, insn) { |
| 200 | if (!prev_insn || memcmp(&insn->orc, &prev_insn->orc, |
| 201 | sizeof(struct orc_entry))) { |
| 202 | |
Peter Zijlstra | 8b5fa6b | 2020-03-12 11:23:36 +0100 | [diff] [blame] | 203 | if (create_orc_entry(file->elf, u_sec, ip_relasec, idx, |
Josh Poimboeuf | 627fce1 | 2017-07-11 10:33:42 -0500 | [diff] [blame] | 204 | insn->sec, insn->offset, |
| 205 | &insn->orc)) |
| 206 | return -1; |
| 207 | |
| 208 | idx++; |
| 209 | } |
| 210 | prev_insn = insn; |
| 211 | } |
| 212 | |
| 213 | /* section terminator */ |
| 214 | if (prev_insn) { |
Peter Zijlstra | 8b5fa6b | 2020-03-12 11:23:36 +0100 | [diff] [blame] | 215 | if (create_orc_entry(file->elf, u_sec, ip_relasec, idx, |
Josh Poimboeuf | 627fce1 | 2017-07-11 10:33:42 -0500 | [diff] [blame] | 216 | prev_insn->sec, |
| 217 | prev_insn->offset + prev_insn->len, |
| 218 | &empty)) |
| 219 | return -1; |
| 220 | |
| 221 | idx++; |
| 222 | } |
| 223 | } |
| 224 | |
Peter Zijlstra | 2b10be2 | 2020-04-17 23:15:00 +0200 | [diff] [blame] | 225 | if (elf_rebuild_rela_section(file->elf, ip_relasec)) |
Josh Poimboeuf | 627fce1 | 2017-07-11 10:33:42 -0500 | [diff] [blame] | 226 | return -1; |
| 227 | |
| 228 | return 0; |
| 229 | } |