From nobody Wed Dec 17 16:54:37 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2402BC77B75 for ; Tue, 18 Apr 2023 21:28:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229978AbjDRV2U (ORCPT ); Tue, 18 Apr 2023 17:28:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44988 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232818AbjDRV2P (ORCPT ); Tue, 18 Apr 2023 17:28:15 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4CA5EAD0F for ; Tue, 18 Apr 2023 14:28:01 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id A2BBC63945 for ; Tue, 18 Apr 2023 21:28:00 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D9872C433A4; Tue, 18 Apr 2023 21:27:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1681853280; bh=mkUcunGwZcbLDMBJzfgmVtTvYRmD88J1hdWzV9cPHn4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=f8rTKQmVKoRowFB1Jq7qGx9DQ9/NsrY/BoSFNs1K1A9O4YYLn7ohcGN8TuFihLB+g TaTb3hO0eTLP2LBZvrGkcwkmN0GGyV89ICl3jyL6BZAkLOk+fC1e3+BtI55vftBGSr 2ZP6o0Gczg/JnPUuXVViIT/qYPw63CdFJz5ZfXzV6f0sWnquxWV87W1dkvtUi7bWZ5 42Ag6eY86awyKJWJIx8O9cRunf8u7jg1ZYxIr5cEXK8S+ks09CXhFV1uXCdIkMOZkT M0jP+AOkdATyQNedY3gsvuduYfPV8yxjkXaZVRk2YyBjlFz6dyad/n+fGrNI9Yon46 OD6yD/yFptwww== From: Josh Poimboeuf To: x86@kernel.org Cc: linux-kernel@vger.kernel.org, Peter Zijlstra , Miroslav Benes , Nick Desaulniers Subject: [PATCH v3 2/8] objtool: Add verbose option for disassembling affected functions Date: Tue, 18 Apr 2023 14:27:48 -0700 Message-Id: X-Mailer: git-send-email 2.39.2 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" When a warning is associated with a function, add an option to disassemble that function. This makes it easier for reporters to submit the information needed to diagnose objtool warnings. Signed-off-by: Josh Poimboeuf --- tools/objtool/Documentation/objtool.txt | 5 ++ tools/objtool/builtin-check.c | 5 ++ tools/objtool/check.c | 77 +++++++++++++++++++++++++ tools/objtool/include/objtool/builtin.h | 1 + 4 files changed, 88 insertions(+) diff --git a/tools/objtool/Documentation/objtool.txt b/tools/objtool/Docume= ntation/objtool.txt index 8e53fc6735ef..4d6c5acde7a3 100644 --- a/tools/objtool/Documentation/objtool.txt +++ b/tools/objtool/Documentation/objtool.txt @@ -244,6 +244,11 @@ To achieve the validation, objtool enforces the follow= ing rules: Objtool warnings ---------------- =20 +NOTE: When requesting help with an objtool warning, please recreate with +OBJTOOL_VERBOSE=3D1 (e.g., "make OBJTOOL_VERBOSE=3D1") and send the full +output, including any disassembly below the warning, to the objtool +maintainers. + For asm files, if you're getting an error which doesn't make sense, first make sure that the affected code follows the above rules. =20 diff --git a/tools/objtool/builtin-check.c b/tools/objtool/builtin-check.c index 7c175198d09f..5e21cfb7661d 100644 --- a/tools/objtool/builtin-check.c +++ b/tools/objtool/builtin-check.c @@ -93,6 +93,7 @@ static const struct option check_options[] =3D { OPT_BOOLEAN(0, "no-unreachable", &opts.no_unreachable, "skip 'unreachable= instruction' warnings"), OPT_BOOLEAN(0, "sec-address", &opts.sec_address, "print section addresses= in warnings"), OPT_BOOLEAN(0, "stats", &opts.stats, "print statistics"), + OPT_BOOLEAN('v', "verbose", &opts.verbose, "verbose warnings"), =20 OPT_END(), }; @@ -118,6 +119,10 @@ int cmd_parse_options(int argc, const char **argv, con= st char * const usage[]) parse_options(envc, envv, check_options, env_usage, 0); } =20 + env =3D getenv("OBJTOOL_VERBOSE"); + if (env && !strcmp(env, "1")) + opts.verbose =3D true; + argc =3D parse_options(argc, argv, check_options, usage, 0); if (argc !=3D 1) usage_with_options(usage, check_options); diff --git a/tools/objtool/check.c b/tools/objtool/check.c index a00931342c7e..c63e0867daca 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -4530,6 +4530,81 @@ static int validate_reachable_instructions(struct ob= jtool_file *file) return warnings; } =20 +/* 'funcs' is a space-separated list of function names */ +static int disas_funcs(const char *funcs) +{ + const char *objdump_str, *cross_compile; + int size, ret; + char *cmd; + + cross_compile =3D getenv("CROSS_COMPILE"); + + objdump_str =3D "%sobjdump -wdr %s | gawk -M -v _funcs=3D'%s' '" + "BEGIN { split(_funcs, funcs); }" + "/^$/ { func_match =3D 0; }" + "/<.*>:/ { " + "f =3D gensub(/.*<(.*)>:/, \"\\\\1\", 1);" + "for (i in funcs) {" + "if (funcs[i] =3D=3D f) {" + "func_match =3D 1;" + "base =3D strtonum(\"0x\" $1);" + "break;" + "}" + "}" + "}" + "{" + "if (func_match) {" + "addr =3D strtonum(\"0x\" $1);" + "printf(\"%%04x \", addr - base);" + "print;" + "}" + "}' 1>&2"; + + /* fake snprintf() to calculate the size */ + size =3D snprintf(NULL, 0, objdump_str, cross_compile, objname, funcs) + = 1; + if (size <=3D 0) { + WARN("objdump string size calculation failed"); + return -1; + } + + cmd =3D malloc(size); + + /* real snprintf() */ + snprintf(cmd, size, objdump_str, cross_compile, objname, funcs); + ret =3D system(cmd); + if (ret) { + WARN("disassembly failed: %d", ret); + return -1; + } + + return 0; +} + +static int disas_warned_funcs(struct objtool_file *file) +{ + struct symbol *sym; + char *funcs =3D NULL, *tmp; + + for_each_sym(file, sym) { + if (sym->warned) { + if (!funcs) { + funcs =3D malloc(strlen(sym->name) + 1); + strcpy(funcs, sym->name); + } else { + tmp =3D malloc(strlen(funcs) + strlen(sym->name) + 2); + sprintf(tmp, "%s %s", funcs, sym->name); + free(funcs); + funcs =3D tmp; + } + } + } + + if (funcs) + disas_funcs(funcs); + + return 0; +} + int check(struct objtool_file *file) { int ret, warnings =3D 0; @@ -4674,6 +4749,8 @@ int check(struct objtool_file *file) warnings +=3D ret; } =20 + if (opts.verbose) + disas_warned_funcs(file); =20 if (opts.stats) { printf("nr_insns_visited: %ld\n", nr_insns_visited); diff --git a/tools/objtool/include/objtool/builtin.h b/tools/objtool/includ= e/objtool/builtin.h index 2a108e648b7a..fcca6662c8b4 100644 --- a/tools/objtool/include/objtool/builtin.h +++ b/tools/objtool/include/objtool/builtin.h @@ -37,6 +37,7 @@ struct opts { bool no_unreachable; bool sec_address; bool stats; + bool verbose; }; =20 extern struct opts opts; --=20 2.39.2