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charset="utf-8" The code to validate a branch loops through all instructions of the branch and validate each instruction. Move the code to validate an instruction to a separated function. Signed-off-by: Alexandre Chartre --- tools/objtool/check.c | 375 +++++++++++++++++++++++------------------- 1 file changed, 208 insertions(+), 167 deletions(-) diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 2c73c8d3515d..36ec08b8d654 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -3527,6 +3527,11 @@ static bool skip_alt_group(struct instruction *insn) return alt_insn->type =3D=3D INSN_CLAC || alt_insn->type =3D=3D INSN_STAC; } =20 +static int validate_insn(struct objtool_file *file, struct symbol *func, + struct instruction *insn, struct insn_state *statep, + struct instruction *prev_insn, struct instruction *next_insn, + bool *validate_nextp); + /* * Follow the branch starting at the given instruction, and recursively fo= llow * any other branches (jumps). Meanwhile, track the frame pointer state at @@ -3536,10 +3541,9 @@ static bool skip_alt_group(struct instruction *insn) static int validate_branch(struct objtool_file *file, struct symbol *func, struct instruction *insn, struct insn_state state) { - struct alternative *alt; struct instruction *next_insn, *prev_insn =3D NULL; struct section *sec; - u8 visited; + bool validate_next; int ret; =20 if (func && func->ignore) @@ -3566,232 +3570,269 @@ static int validate_branch(struct objtool_file *f= ile, struct symbol *func, return 1; } =20 - visited =3D VISITED_BRANCH << state.uaccess; - if (insn->visited & VISITED_BRANCH_MASK) { - if (!insn->hint && !insn_cfi_match(insn, &state.cfi)) - return 1; + ret =3D validate_insn(file, func, insn, &state, + prev_insn, next_insn, + &validate_next); + if (!validate_next) + break; =20 - if (insn->visited & visited) + if (!next_insn) { + if (state.cfi.cfa.base =3D=3D CFI_UNDEFINED) return 0; - } else { - nr_insns_visited++; + if (file->ignore_unreachables) + return 0; + + WARN("%s%sunexpected end of section %s", + func ? func->name : "", func ? "(): " : "", + sec->name); + return 1; } =20 - if (state.noinstr) - state.instr +=3D insn->instr; + prev_insn =3D insn; + insn =3D next_insn; + } =20 - if (insn->hint) { - if (insn->restore) { - struct instruction *save_insn, *i; + return ret; +} =20 - i =3D insn; - save_insn =3D NULL; +static int validate_insn(struct objtool_file *file, struct symbol *func, + struct instruction *insn, struct insn_state *statep, + struct instruction *prev_insn, struct instruction *next_insn, + bool *validate_nextp) +{ + struct alternative *alt; + u8 visited; + int ret; =20 - sym_for_each_insn_continue_reverse(file, func, i) { - if (i->save) { - save_insn =3D i; - break; - } - } + /* + * Indicate that, by default, the calling function should not + * validate the next instruction and validation should be + * stopped. That way this function can stop validation by just + * returning at any point before reaching the end of the function. + * + * If the end of this function is reached then that means that the + * validation should continue and the caller should validate the + * next instruction, so *validate_nextp will be set to true at + * that point. + */ + *validate_nextp =3D false; =20 - if (!save_insn) { - WARN_INSN(insn, "no corresponding CFI save for CFI restore"); - return 1; - } + visited =3D VISITED_BRANCH << statep->uaccess; + if (insn->visited & VISITED_BRANCH_MASK) { + if (!insn->hint && !insn_cfi_match(insn, &statep->cfi)) + return 1; =20 - if (!save_insn->visited) { - /* - * If the restore hint insn is at the - * beginning of a basic block and was - * branched to from elsewhere, and the - * save insn hasn't been visited yet, - * defer following this branch for now. - * It will be seen later via the - * straight-line path. - */ - if (!prev_insn) - return 0; + if (insn->visited & visited) + return 0; + } else { + nr_insns_visited++; + } =20 - WARN_INSN(insn, "objtool isn't smart enough to handle this CFI save/r= estore combo"); - return 1; - } + if (statep->noinstr) + statep->instr +=3D insn->instr; =20 - insn->cfi =3D save_insn->cfi; - nr_cfi_reused++; - } + if (insn->hint) { + if (insn->restore) { + struct instruction *save_insn, *i; =20 - state.cfi =3D *insn->cfi; - } else { - /* XXX track if we actually changed state.cfi */ + i =3D insn; + save_insn =3D NULL; =20 - if (prev_insn && !cficmp(prev_insn->cfi, &state.cfi)) { - insn->cfi =3D prev_insn->cfi; - nr_cfi_reused++; - } else { - insn->cfi =3D cfi_hash_find_or_add(&state.cfi); + sym_for_each_insn_continue_reverse(file, func, i) { + if (i->save) { + save_insn =3D i; + break; + } } - } =20 - insn->visited |=3D visited; + if (!save_insn) { + WARN_INSN(insn, "no corresponding CFI save for CFI restore"); + return 1; + } =20 - if (propagate_alt_cfi(file, insn)) - return 1; + if (!save_insn->visited) { + /* + * If the restore hint insn is at the + * beginning of a basic block and was + * branched to from elsewhere, and the + * save insn hasn't been visited yet, + * defer following this branch for now. + * It will be seen later via the + * straight-line path. + */ + if (!prev_insn) + return 0; =20 - if (insn->alts) { - for (alt =3D insn->alts; alt; alt =3D alt->next) { - ret =3D validate_branch(file, func, alt->insn, state); - if (ret) { - BT_INSN(insn, "(alt)"); - return ret; - } + WARN_INSN(insn, "objtool isn't smart enough to handle this CFI save/re= store combo"); + return 1; } + + insn->cfi =3D save_insn->cfi; + nr_cfi_reused++; } =20 - if (skip_alt_group(insn)) - return 0; + statep->cfi =3D *insn->cfi; + } else { + /* XXX track if we actually changed statep->cfi */ =20 - if (handle_insn_ops(insn, next_insn, &state)) - return 1; + if (prev_insn && !cficmp(prev_insn->cfi, &statep->cfi)) { + insn->cfi =3D prev_insn->cfi; + nr_cfi_reused++; + } else { + insn->cfi =3D cfi_hash_find_or_add(&statep->cfi); + } + } =20 - switch (insn->type) { + insn->visited |=3D visited; =20 - case INSN_RETURN: - return validate_return(func, insn, &state); + if (propagate_alt_cfi(file, insn)) + return 1; =20 - case INSN_CALL: - case INSN_CALL_DYNAMIC: - ret =3D validate_call(file, insn, &state); - if (ret) + if (insn->alts) { + for (alt =3D insn->alts; alt; alt =3D alt->next) { + ret =3D validate_branch(file, func, alt->insn, *statep); + if (ret) { + BT_INSN(insn, "(alt)"); return ret; - - if (opts.stackval && func && !is_special_call(insn) && - !has_valid_stack_frame(&state)) { - WARN_INSN(insn, "call without frame pointer save/setup"); - return 1; } + } + } =20 - break; - - case INSN_JUMP_CONDITIONAL: - case INSN_JUMP_UNCONDITIONAL: - if (is_sibling_call(insn)) { - ret =3D validate_sibling_call(file, insn, &state); - if (ret) - return ret; - - } else if (insn->jump_dest) { - ret =3D validate_branch(file, func, - insn->jump_dest, state); - if (ret) { - BT_INSN(insn, "(branch)"); - return ret; - } - } + if (skip_alt_group(insn)) + return 0; =20 - if (insn->type =3D=3D INSN_JUMP_UNCONDITIONAL) - return 0; + if (handle_insn_ops(insn, next_insn, statep)) + return 1; =20 - break; + switch (insn->type) { =20 - case INSN_JUMP_DYNAMIC: - case INSN_JUMP_DYNAMIC_CONDITIONAL: - if (is_sibling_call(insn)) { - ret =3D validate_sibling_call(file, insn, &state); - if (ret) - return ret; - } + case INSN_RETURN: + return validate_return(func, insn, statep); =20 - if (insn->type =3D=3D INSN_JUMP_DYNAMIC) - return 0; + case INSN_CALL: + case INSN_CALL_DYNAMIC: + ret =3D validate_call(file, insn, statep); + if (ret) + return ret; =20 - break; + if (opts.stackval && func && !is_special_call(insn) && + !has_valid_stack_frame(statep)) { + WARN_INSN(insn, "call without frame pointer save/setup"); + return 1; + } =20 - case INSN_SYSCALL: - if (func && (!next_insn || !next_insn->hint)) { - WARN_INSN(insn, "unsupported instruction in callable function"); - return 1; - } + break; =20 - break; + case INSN_JUMP_CONDITIONAL: + case INSN_JUMP_UNCONDITIONAL: + if (is_sibling_call(insn)) { + ret =3D validate_sibling_call(file, insn, statep); + if (ret) + return ret; =20 - case INSN_SYSRET: - if (func && (!next_insn || !next_insn->hint)) { - WARN_INSN(insn, "unsupported instruction in callable function"); - return 1; + } else if (insn->jump_dest) { + ret =3D validate_branch(file, func, + insn->jump_dest, *statep); + if (ret) { + BT_INSN(insn, "(branch)"); + return ret; } + } =20 + if (insn->type =3D=3D INSN_JUMP_UNCONDITIONAL) return 0; =20 - case INSN_STAC: - if (!opts.uaccess) - break; + break; =20 - if (state.uaccess) { - WARN_INSN(insn, "recursive UACCESS enable"); - return 1; - } + case INSN_JUMP_DYNAMIC: + case INSN_JUMP_DYNAMIC_CONDITIONAL: + if (is_sibling_call(insn)) { + ret =3D validate_sibling_call(file, insn, statep); + if (ret) + return ret; + } =20 - state.uaccess =3D true; - break; + if (insn->type =3D=3D INSN_JUMP_DYNAMIC) + return 0; =20 - case INSN_CLAC: - if (!opts.uaccess) - break; + break; =20 - if (!state.uaccess && func) { - WARN_INSN(insn, "redundant UACCESS disable"); - return 1; - } + case INSN_SYSCALL: + if (func && (!next_insn || !next_insn->hint)) { + WARN_INSN(insn, "unsupported instruction in callable function"); + return 1; + } =20 - if (func_uaccess_safe(func) && !state.uaccess_stack) { - WARN_INSN(insn, "UACCESS-safe disables UACCESS"); - return 1; - } + break; =20 - state.uaccess =3D false; - break; + case INSN_SYSRET: + if (func && (!next_insn || !next_insn->hint)) { + WARN_INSN(insn, "unsupported instruction in callable function"); + return 1; + } =20 - case INSN_STD: - if (state.df) { - WARN_INSN(insn, "recursive STD"); - return 1; - } + return 0; =20 - state.df =3D true; + case INSN_STAC: + if (!opts.uaccess) break; =20 - case INSN_CLD: - if (!state.df && func) { - WARN_INSN(insn, "redundant CLD"); - return 1; - } + if (statep->uaccess) { + WARN_INSN(insn, "recursive UACCESS enable"); + return 1; + } =20 - state.df =3D false; - break; + statep->uaccess =3D true; + break; =20 - default: + case INSN_CLAC: + if (!opts.uaccess) break; + + if (!statep->uaccess && func) { + WARN_INSN(insn, "redundant UACCESS disable"); + return 1; } =20 - if (insn->dead_end) - return 0; + if (func_uaccess_safe(func) && !statep->uaccess_stack) { + WARN_INSN(insn, "UACCESS-safe disables UACCESS"); + return 1; + } =20 - if (!next_insn) { - if (state.cfi.cfa.base =3D=3D CFI_UNDEFINED) - return 0; - if (file->ignore_unreachables) - return 0; + statep->uaccess =3D false; + break; =20 - WARN("%s%sunexpected end of section %s", - func ? func->name : "", func ? "(): " : "", - sec->name); + case INSN_STD: + if (statep->df) { + WARN_INSN(insn, "recursive STD"); return 1; } =20 - prev_insn =3D insn; - insn =3D next_insn; + statep->df =3D true; + break; + + case INSN_CLD: + if (!statep->df && func) { + WARN_INSN(insn, "redundant CLD"); + return 1; + } + + statep->df =3D false; + break; + + default: + break; } =20 + if (insn->dead_end) + return 0; + + /* + * Indicate that the caller should validate the next + * instruction and continue the validation. + */ + *validate_nextp =3D true; + return 0; } =20 --=20 2.43.5