관리-도구

편집 파일: orc_gen.c

// 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_types.h> #include <asm/orc_types.h> #include <objtool/check.h> #include <objtool/warn.h> #include <objtool/endianness.h> static int init_orc_entry(struct orc_entry *orc, struct cfi_state *cfi, struct instruction *insn) { struct cfi_reg *bp = &cfi->regs[CFI_BP]; memset(orc, 0, sizeof(*orc)); if (!cfi) { /* * This is usually either unreachable nops/traps (which don't * trigger unreachable instruction warnings), or * STACK_FRAME_NON_STANDARD functions. */ orc->type = ORC_TYPE_UNDEFINED; return 0; } switch (cfi->type) { case UNWIND_HINT_TYPE_UNDEFINED: orc->type = ORC_TYPE_UNDEFINED; return 0; case UNWIND_HINT_TYPE_END_OF_STACK: orc->type = ORC_TYPE_END_OF_STACK; return 0; case UNWIND_HINT_TYPE_CALL: orc->type = ORC_TYPE_CALL; break; case UNWIND_HINT_TYPE_REGS: orc->type = ORC_TYPE_REGS; break; case UNWIND_HINT_TYPE_REGS_PARTIAL: orc->type = ORC_TYPE_REGS_PARTIAL; break; default: WARN_FUNC("unknown unwind hint type %d", insn->sec, insn->offset, cfi->type); return -1; } orc->signal = cfi->signal; switch (cfi->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, cfi->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 = cfi->cfa.offset; orc->bp_offset = bp->offset; return 0; } static int write_orc_entry(struct elf *elf, struct section *orc_sec, struct section *ip_sec, unsigned int idx, struct section *insn_sec, unsigned long insn_off, struct orc_entry *o) { struct orc_entry *orc; /* populate ORC data */ orc = (struct orc_entry *)orc_sec->data->d_buf + idx; memcpy(orc, o, sizeof(*orc)); orc->sp_offset = bswap_if_needed(orc->sp_offset); orc->bp_offset = bswap_if_needed(orc->bp_offset); /* populate reloc for ip */ if (elf_add_reloc_to_insn(elf, ip_sec, idx * sizeof(int), R_X86_64_PC32, insn_sec, insn_off)) return -1; return 0; } struct orc_list_entry { struct list_head list; struct orc_entry orc; struct section *insn_sec; unsigned long insn_off; }; static int orc_list_add(struct list_head *orc_list, struct orc_entry *orc, struct section *sec, unsigned long offset) { struct orc_list_entry *entry = malloc(sizeof(*entry)); if (!entry) { WARN("malloc failed"); return -1; } entry->orc = *orc; entry->insn_sec = sec; entry->insn_off = offset; list_add_tail(&entry->list, orc_list); return 0; } static unsigned long alt_group_len(struct alt_group *alt_group) { return alt_group->last_insn->offset + alt_group->last_insn->len - alt_group->first_insn->offset; } int orc_create(struct objtool_file *file) { struct section *sec, *orc_sec; unsigned int nr = 0, idx = 0; struct orc_list_entry *entry; struct list_head orc_list; struct orc_entry null = { .type = ORC_TYPE_UNDEFINED }; /* Build a deduplicated list of ORC entries: */ INIT_LIST_HEAD(&orc_list); for_each_sec(file, sec) { struct orc_entry orc, prev_orc = {0}; struct instruction *insn; bool empty = true; if (!sec->text) continue; sec_for_each_insn(file, sec, insn) { struct alt_group *alt_group = insn->alt_group; int i; if (!alt_group) { if (init_orc_entry(&orc, insn->cfi, insn)) return -1; if (!memcmp(&prev_orc, &orc, sizeof(orc))) continue; if (orc_list_add(&orc_list, &orc, sec, insn->offset)) return -1; nr++; prev_orc = orc; empty = false; continue; } /* * Alternatives can have different stack layout * possibilities (but they shouldn't conflict). * Instead of traversing the instructions, use the * alt_group's flattened byte-offset-addressed CFI * array. */ for (i = 0; i < alt_group_len(alt_group); i++) { struct cfi_state *cfi = alt_group->cfi[i]; if (!cfi) continue; /* errors are reported on the original insn */ if (init_orc_entry(&orc, cfi, insn)) return -1; if (!memcmp(&prev_orc, &orc, sizeof(orc))) continue; if (orc_list_add(&orc_list, &orc, insn->sec, insn->offset + i)) return -1; nr++; prev_orc = orc; empty = false; } /* Skip to the end of the alt_group */ insn = alt_group->last_insn; } /* Add a section terminator */ if (!empty) { orc_list_add(&orc_list, &null, sec, sec->sh.sh_size); nr++; } } if (!nr) return 0; /* Create .orc_unwind, .orc_unwind_ip and .rela.orc_unwind_ip sections: */ sec = find_section_by_name(file->elf, ".orc_unwind"); if (sec) { WARN("file already has .orc_unwind section, skipping"); return -1; } orc_sec = elf_create_section(file->elf, ".orc_unwind", 0, sizeof(struct orc_entry), nr); if (!orc_sec) return -1; sec = elf_create_section(file->elf, ".orc_unwind_ip", 0, sizeof(int), nr); if (!sec) return -1; /* Write ORC entries to sections: */ list_for_each_entry(entry, &orc_list, list) { if (write_orc_entry(file->elf, orc_sec, sec, idx++, entry->insn_sec, entry->insn_off, &entry->orc)) return -1; } return 0; }