From patchwork Mon Jul 26 16:12:07 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrii Nakryiko X-Patchwork-Id: 12400033 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-17.0 required=3.0 tests=BAYES_00,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DD58BC00143 for ; Mon, 26 Jul 2021 16:13:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C833460F92 for ; Mon, 26 Jul 2021 16:13:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233333AbhGZPch convert rfc822-to-8bit (ORCPT ); Mon, 26 Jul 2021 11:32:37 -0400 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:1448 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S233283AbhGZPcQ (ORCPT ); Mon, 26 Jul 2021 11:32:16 -0400 Received: from pps.filterd (m0001303.ppops.net [127.0.0.1]) by m0001303.ppops.net (8.16.0.43/8.16.0.43) with SMTP id 16QGCe3u001322 for ; Mon, 26 Jul 2021 09:12:44 -0700 Received: from mail.thefacebook.com ([163.114.132.120]) by m0001303.ppops.net with ESMTP id 3a0ej0ttt0-16 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Mon, 26 Jul 2021 09:12:43 -0700 Received: from intmgw006.03.ash8.facebook.com (2620:10d:c085:108::4) by mail.thefacebook.com (2620:10d:c085:11d::7) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Mon, 26 Jul 2021 09:12:41 -0700 Received: by devbig012.ftw2.facebook.com (Postfix, from userid 137359) id 1F2523D405AD; Mon, 26 Jul 2021 09:12:34 -0700 (PDT) From: Andrii Nakryiko To: , , CC: , , Peter Zijlstra Subject: [PATCH v2 bpf-next 10/14] libbpf: add user_ctx support to bpf_link_create() API Date: Mon, 26 Jul 2021 09:12:07 -0700 Message-ID: <20210726161211.925206-11-andrii@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210726161211.925206-1-andrii@kernel.org> References: <20210726161211.925206-1-andrii@kernel.org> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-ORIG-GUID: T8nOvXpUiPsCKKGVx5HFGB8InhBwwWms X-Proofpoint-GUID: T8nOvXpUiPsCKKGVx5HFGB8InhBwwWms X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.391,18.0.790 definitions=2021-07-26_10:2021-07-26,2021-07-26 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 bulkscore=0 lowpriorityscore=0 adultscore=0 clxscore=1015 malwarescore=0 mlxlogscore=999 mlxscore=0 suspectscore=0 phishscore=0 impostorscore=0 priorityscore=1501 spamscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2104190000 definitions=main-2107260094 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Add ability to specify user_ctx value when creating BPF perf link with bpf_link_create() low-level API. Given BPF_LINK_CREATE command is growing and keeps getting new fields that are specific to the type of BPF_LINK, extend libbpf side of bpf_link_create() API and corresponding OPTS struct to accomodate such changes. Add extra checks to prevent using incompatible/unexpected combinations of fields. Signed-off-by: Andrii Nakryiko --- tools/lib/bpf/bpf.c | 32 +++++++++++++++++++++++++------- tools/lib/bpf/bpf.h | 8 +++++++- tools/lib/bpf/libbpf_internal.h | 32 ++++++++++++++++++++++---------- 3 files changed, 54 insertions(+), 18 deletions(-) diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c index 86dcac44f32f..8dcbee80ced7 100644 --- a/tools/lib/bpf/bpf.c +++ b/tools/lib/bpf/bpf.c @@ -684,8 +684,13 @@ int bpf_link_create(int prog_fd, int target_fd, iter_info_len = OPTS_GET(opts, iter_info_len, 0); target_btf_id = OPTS_GET(opts, target_btf_id, 0); - if (iter_info_len && target_btf_id) - return libbpf_err(-EINVAL); + /* validate we don't have unexpected combinations of non-zero fields */ + if (iter_info_len || target_btf_id) { + if (iter_info_len && target_btf_id) + return libbpf_err(-EINVAL); + if (!OPTS_ZEROED(opts, target_btf_id)) + return libbpf_err(-EINVAL); + } memset(&attr, 0, sizeof(attr)); attr.link_create.prog_fd = prog_fd; @@ -693,14 +698,27 @@ int bpf_link_create(int prog_fd, int target_fd, attr.link_create.attach_type = attach_type; attr.link_create.flags = OPTS_GET(opts, flags, 0); - if (iter_info_len) { - attr.link_create.iter_info = - ptr_to_u64(OPTS_GET(opts, iter_info, (void *)0)); - attr.link_create.iter_info_len = iter_info_len; - } else if (target_btf_id) { + if (target_btf_id) { attr.link_create.target_btf_id = target_btf_id; + goto proceed; } + switch (attach_type) { + case BPF_TRACE_ITER: + attr.link_create.iter_info = ptr_to_u64(OPTS_GET(opts, iter_info, (void *)0)); + attr.link_create.iter_info_len = iter_info_len; + break; + case BPF_PERF_EVENT: + attr.link_create.perf_event.user_ctx = OPTS_GET(opts, perf_event.user_ctx, 0); + if (!OPTS_ZEROED(opts, perf_event)) + return libbpf_err(-EINVAL); + break; + default: + if (!OPTS_ZEROED(opts, flags)) + return libbpf_err(-EINVAL); + break; + } +proceed: fd = sys_bpf(BPF_LINK_CREATE, &attr, sizeof(attr)); return libbpf_err_errno(fd); } diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h index 4f758f8f50cd..49d5d08c3832 100644 --- a/tools/lib/bpf/bpf.h +++ b/tools/lib/bpf/bpf.h @@ -177,8 +177,14 @@ struct bpf_link_create_opts { union bpf_iter_link_info *iter_info; __u32 iter_info_len; __u32 target_btf_id; + union { + struct { + __u64 user_ctx; + } perf_event; + }; + size_t :0; }; -#define bpf_link_create_opts__last_field target_btf_id +#define bpf_link_create_opts__last_field perf_event LIBBPF_API int bpf_link_create(int prog_fd, int target_fd, enum bpf_attach_type attach_type, diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h index 016ca7cb4f8a..e371188c8f87 100644 --- a/tools/lib/bpf/libbpf_internal.h +++ b/tools/lib/bpf/libbpf_internal.h @@ -195,6 +195,17 @@ void *libbpf_add_mem(void **data, size_t *cap_cnt, size_t elem_sz, size_t cur_cnt, size_t max_cnt, size_t add_cnt); int libbpf_ensure_mem(void **data, size_t *cap_cnt, size_t elem_sz, size_t need_cnt); +static inline bool libbpf_is_mem_zeroed(const char *p, ssize_t len) +{ + while (len > 0) { + if (*p) + return false; + p++; + len--; + } + return true; +} + static inline bool libbpf_validate_opts(const char *opts, size_t opts_sz, size_t user_sz, const char *type_name) @@ -203,16 +214,9 @@ static inline bool libbpf_validate_opts(const char *opts, pr_warn("%s size (%zu) is too small\n", type_name, user_sz); return false; } - if (user_sz > opts_sz) { - size_t i; - - for (i = opts_sz; i < user_sz; i++) { - if (opts[i]) { - pr_warn("%s has non-zero extra bytes\n", - type_name); - return false; - } - } + if (!libbpf_is_mem_zeroed(opts + opts_sz, (ssize_t)user_sz - opts_sz)) { + pr_warn("%s has non-zero extra bytes\n", type_name); + return false; } return true; } @@ -232,6 +236,14 @@ static inline bool libbpf_validate_opts(const char *opts, (opts)->field = value; \ } while (0) +#define OPTS_ZEROED(opts, last_nonzero_field) \ +({ \ + ssize_t __off = offsetofend(typeof(*(opts)), last_nonzero_field); \ + !(opts) || libbpf_is_mem_zeroed((const void *)opts + __off, \ + (opts)->sz - __off); \ +}) + + int parse_cpu_mask_str(const char *s, bool **mask, int *mask_sz); int parse_cpu_mask_file(const char *fcpu, bool **mask, int *mask_sz); int libbpf__load_raw_btf(const char *raw_types, size_t types_len,