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1// SPDX-License-Identifier: GPL-2.0-or-later2/*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 layout88 * possibilities (but they shouldn't conflict).89 * Instead of traversing the instructions, use the90 * alt_group's flattened byte-offset-addressed CFI91 * 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}148