From patchwork Wed Oct 11 09:17:31 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alan Maguire X-Patchwork-Id: 13416934 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B89D11A73C for ; Wed, 11 Oct 2023 09:18:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="aLG43kGt" Received: from mx0b-00069f02.pphosted.com (mx0b-00069f02.pphosted.com [205.220.177.32]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C449D91 for ; Wed, 11 Oct 2023 02:18:10 -0700 (PDT) Received: from pps.filterd (m0246631.ppops.net [127.0.0.1]) by mx0b-00069f02.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 39B7mejX022735; Wed, 11 Oct 2023 09:17:53 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding; s=corp-2023-03-30; bh=eajcGv3Q0nZMWbEn/Kim6ne4hnfKLFcuDVWKEyoO2iM=; b=aLG43kGtpTNfQabWf+bsy7HuOulpxAxbcPwXx5a8eL6XIKFQ9SngvT5KhRr/JRbPvGPC EKz/ZP1QADGvNRQdz7tEzxVEXPGLYieiKFlhLWldd4h4+ARNxyacR00qlAsdvIccslTW R32rY0Jzdek+VuPbJoP80dyo15cTfbf4kqscEz74dCaOKubyU+Nm9AugaVIv9v4HfHnp GAFjs1496zYbFNDkwEfwIU7K9UuFrh0lIDXhbzw8Lh/Cy1T69scHET0pJm7yXyvGA6u0 7YU0wSPN3pL/H8jGfDY4E7LrH5z1BZdnwKJIsn3P9/nN4OkWekIqsBl8mUIVM62RHhtI BA== Received: from phxpaimrmta01.imrmtpd1.prodappphxaev1.oraclevcn.com (phxpaimrmta01.appoci.oracle.com [138.1.114.2]) by mx0b-00069f02.pphosted.com (PPS) with ESMTPS id 3tjx43qc6u-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 11 Oct 2023 09:17:53 +0000 Received: from pps.filterd (phxpaimrmta01.imrmtpd1.prodappphxaev1.oraclevcn.com [127.0.0.1]) by phxpaimrmta01.imrmtpd1.prodappphxaev1.oraclevcn.com (8.17.1.19/8.17.1.19) with ESMTP id 39B8eHjf015032; Wed, 11 Oct 2023 09:17:52 GMT Received: from pps.reinject (localhost [127.0.0.1]) by phxpaimrmta01.imrmtpd1.prodappphxaev1.oraclevcn.com (PPS) with ESMTPS id 3tjws8d16q-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 11 Oct 2023 09:17:52 +0000 Received: from phxpaimrmta01.imrmtpd1.prodappphxaev1.oraclevcn.com (phxpaimrmta01.imrmtpd1.prodappphxaev1.oraclevcn.com [127.0.0.1]) by pps.reinject (8.17.1.5/8.17.1.5) with ESMTP id 39B9Hbxo020344; Wed, 11 Oct 2023 09:17:51 GMT Received: from bpf.uk.oracle.com (dhcp-10-175-183-173.vpn.oracle.com [10.175.183.173]) by phxpaimrmta01.imrmtpd1.prodappphxaev1.oraclevcn.com (PPS) with ESMTP id 3tjws8d0tb-4; Wed, 11 Oct 2023 09:17:51 +0000 From: Alan Maguire To: acme@kernel.org, andrii.nakryiko@gmail.com Cc: jolsa@kernel.org, ast@kernel.org, daniel@iogearbox.net, eddyz87@gmail.com, martin.lau@linux.dev, song@kernel.org, yhs@fb.com, john.fastabend@gmail.com, kpsingh@kernel.org, sdf@google.com, haoluo@google.com, mykolal@fb.com, bpf@vger.kernel.org, Alan Maguire , Andrii Nakryiko Subject: [RFC dwarves 3/4] pahole: add --btf_features=feature1[,feature2...] support Date: Wed, 11 Oct 2023 10:17:31 +0100 Message-Id: <20231011091732.93254-4-alan.maguire@oracle.com> X-Mailer: git-send-email 2.39.3 In-Reply-To: <20231011091732.93254-1-alan.maguire@oracle.com> References: <20231011091732.93254-1-alan.maguire@oracle.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.267,Aquarius:18.0.980,Hydra:6.0.619,FMLib:17.11.176.26 definitions=2023-10-11_06,2023-10-10_01,2023-05-22_02 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 adultscore=0 mlxlogscore=999 mlxscore=0 bulkscore=0 phishscore=0 suspectscore=0 spamscore=0 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2309180000 definitions=main-2310110081 X-Proofpoint-ORIG-GUID: 3AiKEQbUb6pG1NK3ZYsnWXq9tcS55vNL X-Proofpoint-GUID: 3AiKEQbUb6pG1NK3ZYsnWXq9tcS55vNL X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF, RCVD_IN_DNSWL_BLOCKED,RCVD_IN_MSPIKE_H5,RCVD_IN_MSPIKE_WL, SPF_HELO_NONE,SPF_NONE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net X-Patchwork-State: RFC This allows consumers to specify an opt-in set of features they want to use in BTF encoding. Supported features are encode_force Ignore invalid symbols when encoding BTF. var Encode variables using BTF_KIND_VAR in BTF. float Encode floating-point types in BTF. decl_tag Encode declaration tags using BTF_KIND_DECL_TAG. type_tag Encode type tags using BTF_KIND_TYPE_TAG. enum64 Encode enum64 values with BTF_KIND_ENUM64. optimized Encode representations of optimized functions with suffixes like ".isra.0" etc consistent Avoid encoding inconsistent static functions. These occur when a parameter is optimized out in some CUs and not others, or when the same function name has inconsistent BTF descriptions in different CUs. Specifying "--btf_features=all" is the equivalent to setting all of the above. If pahole does not know about a feature it silently ignores it. These properties allow us to use the --btf_features option in the kernel pahole_flags.sh script to specify the desired set of features. If a new feature is not present in pahole but requested, pahole BTF encoding will not complain (but will not encode the feature). Suggested-by: Andrii Nakryiko Signed-off-by: Alan Maguire --- man-pages/pahole.1 | 20 +++++++++++ pahole.c | 87 +++++++++++++++++++++++++++++++++++++++++++++- 2 files changed, 106 insertions(+), 1 deletion(-) diff --git a/man-pages/pahole.1 b/man-pages/pahole.1 index c1b48de..7c072dc 100644 --- a/man-pages/pahole.1 +++ b/man-pages/pahole.1 @@ -273,6 +273,26 @@ Generate BTF for functions with optimization-related suffixes (.isra, .constprop .B \-\-btf_gen_all Allow using all the BTF features supported by pahole. +.TP +.B \-\-btf_features=FEATURE_LIST +Encode BTF using the specified feature list, or specify 'all' for all features supported. This single parameter value can be used as an alternative to unsing multiple BTF-related options. Supported features are + +.nf + encode_force Ignore invalid symbols when encoding BTF. + var Encode variables using BTF_KIND_VAR in BTF. + float Encode floating-point types in BTF. + decl_tag Encode declaration tags using BTF_KIND_DECL_TAG. + type_tag Encode type tags using BTF_KIND_TYPE_TAG. + enum64 Encode enum64 values with BTF_KIND_ENUM64. + optimized Encode representations of optimized functions + with suffixes like ".isra.0" etc + consistent Avoid encoding inconsistent static functions. + These occur when a parameter is optimized out + in some CUs and not others, or when the same + function name has inconsistent BTF descriptions + in different CUs. +.fi + .TP .B \-l, \-\-show_first_biggest_size_base_type_member Show first biggest size base_type member. diff --git a/pahole.c b/pahole.c index 7a41dc3..4f00b08 100644 --- a/pahole.c +++ b/pahole.c @@ -1229,6 +1229,83 @@ ARGP_PROGRAM_VERSION_HOOK_DEF = dwarves_print_version; #define ARGP_skip_emitting_atomic_typedefs 338 #define ARGP_btf_gen_optimized 339 #define ARGP_skip_encoding_btf_inconsistent_proto 340 +#define ARGP_btf_features 341 + +/* --btf_features=feature1[,feature2,..] option allows us to specify + * opt-in features (or "all"); these are translated into conf_load + * values by specifying the associated bool offset and whether it + * is a skip option or not; btf_features is for opting _into_ features + * so for skip options we have to reverse the logic. For example + * "--skip_encoding_btf_type_tag --btf_gen_floats" translate to + * "--btf_features=type_tag,float" + */ +#define BTF_FEATURE(name, alias, skip) \ + { #name, #alias, offsetof(struct conf_load, alias), skip } + +struct btf_feature { + const char *name; + const char *option_alias; + size_t conf_load_offset; + bool skip; +} btf_features[] = { + BTF_FEATURE(encode_force, btf_encode_force, false), + BTF_FEATURE(var, skip_encoding_btf_vars, true), + BTF_FEATURE(float, btf_gen_floats, false), + BTF_FEATURE(decl_tag, skip_encoding_btf_decl_tag, true), + BTF_FEATURE(type_tag, skip_encoding_btf_type_tag, true), + BTF_FEATURE(enum64, skip_encoding_btf_enum64, true), + BTF_FEATURE(optimized, btf_gen_optimized, false), + /* the "skip" in skip_encoding_btf_inconsistent_proto is misleading + * here; this is a positive feature to ensure consistency of + * representation rather than a negative option which we want + * to invert. So as a result, "skip" is false here. + */ + BTF_FEATURE(consistent, skip_encoding_btf_inconsistent_proto, false), +}; + +#define BTF_MAX_FEATURES 32 +#define BTF_MAX_FEATURE_STR 256 + +/* Translate --btf_features=feature1[,feature2] into conf_load values. + * Explicitly ignores unrecognized features to allow future specification + * of new opt-in features. + */ +static void parse_btf_features(const char *features, struct conf_load *conf_load) +{ + char *feature_list[BTF_MAX_FEATURES] = {}; + char f[BTF_MAX_FEATURE_STR]; + bool encode_all = false; + int i, j, n = 0; + + strncpy(f, features, sizeof(f)); + + if (strcmp(features, "all") == 0) { + encode_all = true; + } else { + char *saveptr = NULL, *s = f, *t; + + while ((t = strtok_r(s, ",", &saveptr)) != NULL) { + s = NULL; + feature_list[n++] = t; + } + } + + for (i = 0; i < ARRAY_SIZE(btf_features); i++) { + bool *bval = (bool *)(((void *)conf_load) + btf_features[i].conf_load_offset); + bool match = encode_all; + + if (!match) { + for (j = 0; j < n; j++) { + if (strcmp(feature_list[j], btf_features[i].name) == 0) { + match = true; + break; + } + } + } + if (match) + *bval = btf_features[i].skip ? false : true; + } +} static const struct argp_option pahole__options[] = { { @@ -1651,6 +1728,12 @@ static const struct argp_option pahole__options[] = { .key = ARGP_skip_encoding_btf_inconsistent_proto, .doc = "Skip functions that have multiple inconsistent function prototypes sharing the same name, or that use unexpected registers for parameter values." }, + { + .name = "btf_features", + .key = ARGP_btf_features, + .arg = "FEATURE_LIST", + .doc = "Specify supported BTF features in FEATURE_LIST or 'all' for all supported features. See the pahole manual page for the list of supported features." + }, { .name = NULL, } @@ -1796,7 +1879,7 @@ static error_t pahole__options_parser(int key, char *arg, case ARGP_btf_gen_floats: conf_load.btf_gen_floats = true; break; case ARGP_btf_gen_all: - conf_load.btf_gen_floats = true; break; + parse_btf_features("all", &conf_load); break; case ARGP_with_flexible_array: show_with_flexible_array = true; break; case ARGP_prettify_input_filename: @@ -1826,6 +1909,8 @@ static error_t pahole__options_parser(int key, char *arg, conf_load.btf_gen_optimized = true; break; case ARGP_skip_encoding_btf_inconsistent_proto: conf_load.skip_encoding_btf_inconsistent_proto = true; break; + case ARGP_btf_features: + parse_btf_features(arg, &conf_load); break; default: return ARGP_ERR_UNKNOWN; }