From patchwork Wed Feb 6 00:29:48 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrii Nakryiko X-Patchwork-Id: 1037282 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=fb.com Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=fb.com header.i=@fb.com header.b="moLB4igq"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 43vMmM3WTWz9s3x for ; Wed, 6 Feb 2019 11:30:27 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727280AbfBFAaM (ORCPT ); Tue, 5 Feb 2019 19:30:12 -0500 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:43654 "EHLO mx0b-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726806AbfBFAaL (ORCPT ); Tue, 5 Feb 2019 19:30:11 -0500 Received: from pps.filterd (m0109331.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x160S6vU018740 for ; Tue, 5 Feb 2019 16:30:10 -0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-type; s=facebook; bh=rWUNyDv3557yYxSyVpttNBCvZSeFD0sIERVUz1n1jOM=; b=moLB4igqo8G8IxoL9F0NLkUHzV6KwHLuHpcU5Itf5UYQbObUy20TZ30QU3NP/6pVIUKM bGzw9MZQ0zN4kI6svRjMWENsWaeNjE0Y/Nbfc1cxQyXyHIMuXt/4B62l9YjAmmLoScjJ yj8vFo0f9m5uqnFhtuGatC8JflzDyMb659E= Received: from maileast.thefacebook.com ([199.201.65.23]) by mx0a-00082601.pphosted.com with ESMTP id 2qfm2rr61w-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-SHA384 bits=256 verify=NOT) for ; Tue, 05 Feb 2019 16:30:10 -0800 Received: from mx-out.facebook.com (2620:10d:c0a1:3::13) by mail.thefacebook.com (2620:10d:c021:18::175) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA) id 15.1.1531.3; Tue, 5 Feb 2019 16:30:08 -0800 Received: by devvm7221.prn2.facebook.com (Postfix, from userid 137359) id D4FCAA035E47; Tue, 5 Feb 2019 16:30:01 -0800 (PST) Smtp-Origin-Hostprefix: devvm From: Andrii Nakryiko Smtp-Origin-Hostname: devvm7221.prn2.facebook.com To: , , , , , , CC: Andrii Nakryiko Smtp-Origin-Cluster: prn2c23 Subject: [PATCH v2 bpf-next 1/2] btf: separate btf creation and loading Date: Tue, 5 Feb 2019 16:29:48 -0800 Message-ID: <20190206002949.1915237-2-andriin@fb.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190206002949.1915237-1-andriin@fb.com> References: <20190206002949.1915237-1-andriin@fb.com> X-FB-Internal: Safe MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2019-02-05_11:, , signatures=0 X-Proofpoint-Spam-Reason: safe X-FB-Internal: Safe Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org This change splits out previous btf__new functionality of constructing struct btf and loading it into kernel into two: - btf__new() just creates and initializes struct btf - btf__load() attempts to load existing struct btf into kernel btf__free will still close BTF fd, if it was ever loaded successfully into kernel. This change allows users of libbpf to manipulate BTF using its API, without the need to unnecessarily load it into kernel. One of the intended use cases is pahole using libbpf to do DWARF to BTF conversion and deduplication using libbpf, while handling ELF sections overwrites and other concerns on its own. Signed-off-by: Andrii Nakryiko Acked-by: Song Liu --- tools/lib/bpf/btf.c | 53 ++++++++++++++++++++++------------------ tools/lib/bpf/btf.h | 1 + tools/lib/bpf/libbpf.c | 2 +- tools/lib/bpf/libbpf.map | 1 + 4 files changed, 32 insertions(+), 25 deletions(-) diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index 4949f8840bda..1c2ba7182400 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -366,8 +366,6 @@ void btf__free(struct btf *btf) struct btf *btf__new(__u8 *data, __u32 size) { - __u32 log_buf_size = 0; - char *log_buf = NULL; struct btf *btf; int err; @@ -377,15 +375,6 @@ struct btf *btf__new(__u8 *data, __u32 size) btf->fd = -1; - log_buf = malloc(BPF_LOG_BUF_SIZE); - if (!log_buf) { - err = -ENOMEM; - goto done; - } - - *log_buf = 0; - log_buf_size = BPF_LOG_BUF_SIZE; - btf->data = malloc(size); if (!btf->data) { err = -ENOMEM; @@ -395,17 +384,6 @@ struct btf *btf__new(__u8 *data, __u32 size) memcpy(btf->data, data, size); btf->data_size = size; - btf->fd = bpf_load_btf(btf->data, btf->data_size, - log_buf, log_buf_size, false); - - if (btf->fd == -1) { - err = -errno; - pr_warning("Error loading BTF: %s(%d)\n", strerror(errno), errno); - if (log_buf && *log_buf) - pr_warning("%s\n", log_buf); - goto done; - } - err = btf_parse_hdr(btf); if (err) goto done; @@ -417,8 +395,6 @@ struct btf *btf__new(__u8 *data, __u32 size) err = btf_parse_type_sec(btf); done: - free(log_buf); - if (err) { btf__free(btf); return ERR_PTR(err); @@ -427,6 +403,35 @@ struct btf *btf__new(__u8 *data, __u32 size) return btf; } +int btf__load(struct btf* btf) { + __u32 log_buf_size = BPF_LOG_BUF_SIZE; + char *log_buf = NULL; + int err = 0; + + if (btf->fd >= 0) + return -EEXIST; + + log_buf = malloc(log_buf_size); + if (!log_buf) + return -ENOMEM; + + *log_buf = 0; + + btf->fd = bpf_load_btf(btf->data, btf->data_size, + log_buf, log_buf_size, false); + if (btf->fd < 0) { + err = -errno; + pr_warning("Error loading BTF: %s(%d)\n", strerror(errno), errno); + if (*log_buf) + pr_warning("%s\n", log_buf); + goto done; + } + +done: + free(log_buf); + return err; +} + int btf__fd(const struct btf *btf) { return btf->fd; diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h index 25a9d2db035d..e8410887f93a 100644 --- a/tools/lib/bpf/btf.h +++ b/tools/lib/bpf/btf.h @@ -57,6 +57,7 @@ struct btf_ext_header { LIBBPF_API void btf__free(struct btf *btf); LIBBPF_API struct btf *btf__new(__u8 *data, __u32 size); +LIBBPF_API int btf__load(struct btf* btf); LIBBPF_API __s32 btf__find_by_name(const struct btf *btf, const char *type_name); LIBBPF_API __u32 btf__get_nr_types(const struct btf *btf); diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 47969aa0faf8..ff86a43a4336 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -835,7 +835,7 @@ static int bpf_object__elf_collect(struct bpf_object *obj, int flags) obj->efile.maps_shndx = idx; else if (strcmp(name, BTF_ELF_SEC) == 0) { obj->btf = btf__new(data->d_buf, data->d_size); - if (IS_ERR(obj->btf)) { + if (IS_ERR(obj->btf) || btf__load(obj->btf)) { pr_warning("Error loading ELF section %s: %ld. Ignored and continue.\n", BTF_ELF_SEC, PTR_ERR(obj->btf)); obj->btf = NULL; diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index 89c1149e32ee..f5372df143f4 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map @@ -137,6 +137,7 @@ LIBBPF_0.0.2 { btf__get_map_kv_tids; btf__get_nr_types; btf__get_strings; + btf__load; btf_ext__free; btf_ext__func_info_rec_size; btf_ext__line_info_rec_size;