From patchwork Fri Feb 7 02:14:42 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ihor Solodrai X-Patchwork-Id: 13964240 Received: from out-174.mta1.migadu.com (out-174.mta1.migadu.com [95.215.58.174]) (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 49E1F1624E5 for ; Fri, 7 Feb 2025 02:15:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.174 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738894508; cv=none; b=mtDR5Ot+YjCHJap4qoVJRz9N0B/2UsVyGU/KAcPzSa4hCTXiHB1myl7URjU3t4pQKBYt1Sr3+ASxpl4D/+1oH7UYl6WeS7NmbaQL1eMP52dWjHh7hGQMjapLnApSyPaU0ozHYnFH6K+z1w58yclhWgfYUl1VZp9FGzWnJNiN3x4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738894508; c=relaxed/simple; bh=sPtnUM+a4Sf6PqonCFWka4MME0SiGFhUo/lQWyLP72Q=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=WpOtvtOqGMrxaUvYjt/KLkq7/T1joSJWvEhAi4X8LlRuXwfq1gdf5xu+iYvTabkUJXp6EtbYb7jBUGJFvND1k7fgpBtGC2Da8uifHJGhOTcODxTHBW3R2C/rZs/CtTYmcC3+rOTAf49a5TEMiP0PRIMaCrL5dkPDOeRu119iKrg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=kQT7vk6e; arc=none smtp.client-ip=95.215.58.174 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="kQT7vk6e" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1738894503; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=3SATihpDI6gKCPNDFWYK7idPXOGcxYr2zvSTDYPOLQQ=; b=kQT7vk6eTCAIKNUNONebA9oSmRP2fR1Ahr5qJVejfLTcQ4l3I41qEqkj+VQOyXjMPajMeR msEuxTKirl3GqQO+R/HrWzCxAK/CTatKje5QW3GpAhfyQOn2LnE5LAtErhtNWoQwArGXDG FEJ+DtUNEAh+E07ZX41vKdf8vS51sBs= From: Ihor Solodrai To: dwarves@vger.kernel.org, bpf@vger.kernel.org Cc: acme@kernel.org, alan.maguire@oracle.com, ast@kernel.org, andrii@kernel.org, eddyz87@gmail.com, mykolal@fb.com, kernel-team@meta.com Subject: [PATCH dwarves 3/3] pahole: introduce --btf_feature=attributes Date: Thu, 6 Feb 2025 18:14:42 -0800 Message-ID: <20250207021442.155703-4-ihor.solodrai@linux.dev> In-Reply-To: <20250207021442.155703-1-ihor.solodrai@linux.dev> References: <20250207021442.155703-1-ihor.solodrai@linux.dev> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Migadu-Flow: FLOW_OUT Add a feature flag "attributes" (default: false) controlling whether pahole is allowed to generate BTF attributes: type tags and decl tags with kind_flag = 1. This is necessary for backward compatibility, as BPF verifier does not recognize tags with kind_flag = 1 prior to (at least) 6.14-rc1 [1]. [1] https://lore.kernel.org/bpf/20250130201239.1429648-1-ihor.solodrai@linux.dev/ Signed-off-by: Ihor Solodrai Reviewed-by: Alan Maguire --- btf_encoder.c | 6 ++++-- dwarves.h | 1 + pahole.c | 11 +++++++++++ 3 files changed, 16 insertions(+), 2 deletions(-) diff --git a/btf_encoder.c b/btf_encoder.c index d7837c2..0a734d4 100644 --- a/btf_encoder.c +++ b/btf_encoder.c @@ -142,7 +142,8 @@ struct btf_encoder { gen_floats, skip_encoding_decl_tag, tag_kfuncs, - gen_distilled_base; + gen_distilled_base, + encode_attributes; uint32_t array_index_id; struct elf_secinfo *secinfo; size_t seccnt; @@ -800,7 +801,7 @@ static int btf_encoder__add_bpf_arena_type_tags(struct btf_encoder *encoder, str int ret_type_id; int err = 0; - if (!state || !state->elf || !state->elf->kfunc) + if (!encoder->encode_attributes || !state || !state->elf || !state->elf->kfunc) goto out; kfunc = btf_encoder__kfunc_by_name(encoder, state->elf->name); @@ -2553,6 +2554,7 @@ struct btf_encoder *btf_encoder__new(struct cu *cu, const char *detached_filenam encoder->skip_encoding_decl_tag = conf_load->skip_encoding_btf_decl_tag; encoder->tag_kfuncs = conf_load->btf_decl_tag_kfuncs; encoder->gen_distilled_base = conf_load->btf_gen_distilled_base; + encoder->encode_attributes = conf_load->btf_attributes; encoder->verbose = verbose; encoder->has_index_type = false; encoder->need_index_type = false; diff --git a/dwarves.h b/dwarves.h index 8234e1a..99ed783 100644 --- a/dwarves.h +++ b/dwarves.h @@ -89,6 +89,7 @@ struct conf_load { bool reproducible_build; bool btf_decl_tag_kfuncs; bool btf_gen_distilled_base; + bool btf_attributes; uint8_t hashtable_bits; uint8_t max_hashtable_bits; uint16_t kabi_prefix_len; diff --git a/pahole.c b/pahole.c index af3e1cf..0bda249 100644 --- a/pahole.c +++ b/pahole.c @@ -1152,6 +1152,7 @@ ARGP_PROGRAM_VERSION_HOOK_DEF = dwarves_print_version; #define ARG_padding_ge 347 #define ARG_padding 348 #define ARGP_with_embedded_flexible_array 349 +#define ARGP_btf_attributes 350 /* --btf_features=feature1[,feature2,..] allows us to specify * a list of requested BTF features or "default" to enable all default @@ -1210,6 +1211,9 @@ struct btf_feature { BTF_NON_DEFAULT_FEATURE(distilled_base, btf_gen_distilled_base, false), #endif BTF_NON_DEFAULT_FEATURE(global_var, encode_btf_global_vars, false), +#if LIBBPF_MAJOR_VERSION >= 1 && LIBBPF_MINOR_VERSION >= 6 + BTF_NON_DEFAULT_FEATURE(attributes, btf_attributes, false), +#endif }; #define BTF_MAX_FEATURE_STR 1024 @@ -1785,6 +1789,11 @@ static const struct argp_option pahole__options[] = { .key = ARGP_running_kernel_vmlinux, .doc = "Search for, possibly getting from a debuginfo server, a vmlinux matching the running kernel build-id (from /sys/kernel/notes)" }, + { + .name = "btf_attributes", + .key = ARGP_btf_attributes, + .doc = "Allow generation of attributes in BTF. Attributes are the type tags and decl tags with the kind_flag set to 1.", + }, { .name = NULL, } @@ -1979,6 +1988,8 @@ static error_t pahole__options_parser(int key, char *arg, show_supported_btf_features(stdout); exit(0); case ARGP_btf_features_strict: parse_btf_features(arg, true); break; + case ARGP_btf_attributes: + conf_load.btf_attributes = true; break; default: return ARGP_ERR_UNKNOWN; }