From patchwork Sat Nov 21 02:46:13 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrii Nakryiko X-Patchwork-Id: 11923109 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,URIBL_BLOCKED, 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 1DF58C56202 for ; Sat, 21 Nov 2020 02:46:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E297C2240B for ; Sat, 21 Nov 2020 02:46:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727027AbgKUCqe convert rfc822-to-8bit (ORCPT ); Fri, 20 Nov 2020 21:46:34 -0500 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:29652 "EHLO mx0b-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725785AbgKUCqe (ORCPT ); Fri, 20 Nov 2020 21:46:34 -0500 Received: from pps.filterd (m0109331.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 0AL2e9F1018802 for ; Fri, 20 Nov 2020 18:46:33 -0800 Received: from maileast.thefacebook.com ([163.114.130.16]) by mx0a-00082601.pphosted.com with ESMTP id 34xemp3vgf-2 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Fri, 20 Nov 2020 18:46:33 -0800 Received: from intmgw002.08.frc2.facebook.com (2620:10d:c0a8:1b::d) by mail.thefacebook.com (2620:10d:c0a8:83::7) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1979.3; Fri, 20 Nov 2020 18:46:32 -0800 Received: by devbig012.ftw2.facebook.com (Postfix, from userid 137359) id 08CD92EC9CD8; Fri, 20 Nov 2020 18:46:29 -0800 (PST) From: Andrii Nakryiko To: , , , CC: , Subject: [PATCH bpf-next 4/7] libbpf: support attachment of BPF tracing programs to kernel modules Date: Fri, 20 Nov 2020 18:46:13 -0800 Message-ID: <20201121024616.1588175-5-andrii@kernel.org> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20201121024616.1588175-1-andrii@kernel.org> References: <20201121024616.1588175-1-andrii@kernel.org> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.312,18.0.737 definitions=2020-11-20_17:2020-11-20,2020-11-20 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 mlxscore=0 suspectscore=9 adultscore=0 impostorscore=0 clxscore=1015 mlxlogscore=999 spamscore=0 lowpriorityscore=0 malwarescore=0 bulkscore=0 priorityscore=1501 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2011210019 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Teach libbpf to search for BTF types in kernel modules for tracing BPF programs. This allows attachment of raw_tp/fentry/fexit/fmod_ret/etc BPF program types to tracepoints and functions in kernel modules. Signed-off-by: Andrii Nakryiko --- tools/lib/bpf/bpf.c | 1 + tools/lib/bpf/libbpf.c | 105 ++++++++++++++++++++++++++------ tools/lib/bpf/libbpf_internal.h | 1 + 3 files changed, 87 insertions(+), 20 deletions(-) diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c index e371ef91f5e8..dfdad932ef72 100644 --- a/tools/lib/bpf/bpf.c +++ b/tools/lib/bpf/bpf.c @@ -230,6 +230,7 @@ int libbpf__bpf_prog_load(const struct bpf_prog_load_params *load_attr) attr.prog_type = load_attr->prog_type; attr.expected_attach_type = load_attr->expected_attach_type; + attr.attach_btf_obj_id = load_attr->attach_btf_obj_id; attr.attach_btf_id = load_attr->attach_btf_id; attr.attach_prog_fd = load_attr->attach_prog_fd; diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 3425e594132b..c3ca34998a76 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -278,6 +278,7 @@ struct bpf_program { enum bpf_prog_type type; enum bpf_attach_type expected_attach_type; int prog_ifindex; + __u32 attach_btf_obj_id; __u32 attach_btf_id; __u32 attach_prog_fd; void *func_info; @@ -6832,6 +6833,7 @@ load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt, load_attr.license = license; load_attr.attach_btf_id = prog->attach_btf_id; load_attr.attach_prog_fd = prog->attach_prog_fd; + load_attr.attach_btf_obj_id = prog->attach_btf_obj_id; load_attr.attach_btf_id = prog->attach_btf_id; load_attr.kern_version = kern_version; load_attr.prog_ifindex = prog->prog_ifindex; @@ -6927,11 +6929,11 @@ load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt, return ret; } -static int libbpf_find_attach_btf_id(struct bpf_program *prog); +static int libbpf_find_attach_btf_id(struct bpf_program *prog, int *btf_obj_id, int *btf_type_id); int bpf_program__load(struct bpf_program *prog, char *license, __u32 kern_ver) { - int err = 0, fd, i, btf_id; + int err = 0, fd, i; if (prog->obj->loaded) { pr_warn("prog '%s': can't load after object was loaded\n", prog->name); @@ -6941,10 +6943,14 @@ int bpf_program__load(struct bpf_program *prog, char *license, __u32 kern_ver) if ((prog->type == BPF_PROG_TYPE_TRACING || prog->type == BPF_PROG_TYPE_LSM || prog->type == BPF_PROG_TYPE_EXT) && !prog->attach_btf_id) { - btf_id = libbpf_find_attach_btf_id(prog); - if (btf_id <= 0) - return btf_id; - prog->attach_btf_id = btf_id; + int btf_obj_id = 0, btf_type_id = 0; + + err = libbpf_find_attach_btf_id(prog, &btf_obj_id, &btf_type_id); + if (err) + return err; + + prog->attach_btf_id = btf_type_id; + prog->attach_btf_obj_id = btf_obj_id; } if (prog->instances.nr < 0 || !prog->instances.fds) { @@ -8796,8 +8802,8 @@ static int find_btf_by_prefix_kind(const struct btf *btf, const char *prefix, return btf__find_by_name_kind(btf, btf_type_name, kind); } -static inline int __find_vmlinux_btf_id(struct btf *btf, const char *name, - enum bpf_attach_type attach_type) +static inline int find_attach_btf_id(struct btf *btf, const char *name, + enum bpf_attach_type attach_type) { int err; @@ -8828,7 +8834,7 @@ int libbpf_find_vmlinux_btf_id(const char *name, return -EINVAL; } - err = __find_vmlinux_btf_id(btf, name, attach_type); + err = find_attach_btf_id(btf, name, attach_type); if (err <= 0) pr_warn("%s is not found in vmlinux BTF\n", name); @@ -8869,11 +8875,49 @@ static int libbpf_find_prog_btf_id(const char *name, __u32 attach_prog_fd) return err; } -static int libbpf_find_attach_btf_id(struct bpf_program *prog) +static int find_kernel_btf_id(struct bpf_object *obj, const char *attach_name, + enum bpf_attach_type attach_type, + int *btf_obj_id, int *btf_type_id) +{ + int ret, i; + + ret = find_attach_btf_id(obj->btf_vmlinux, attach_name, attach_type); + if (ret > 0) { + *btf_obj_id = 0; /* vmlinux BTF */ + *btf_type_id = ret; + return 0; + } + if (ret != -ENOENT) + return ret; + + ret = load_module_btfs(obj); + if (ret) + return ret; + + for (i = 0; i < obj->btf_module_cnt; i++) { + const struct module_btf *mod = &obj->btf_modules[i]; + + ret = find_attach_btf_id(mod->btf, attach_name, attach_type); + if (ret > 0) { + *btf_obj_id = mod->id; + *btf_type_id = ret; + return 0; + } + if (ret == -ENOENT) + continue; + + return ret; + } + + return -ESRCH; +} + +static int libbpf_find_attach_btf_id(struct bpf_program *prog, int *btf_obj_id, int *btf_type_id) { enum bpf_attach_type attach_type = prog->expected_attach_type; __u32 attach_prog_fd = prog->attach_prog_fd; - const char *name = prog->sec_name; + const char *name = prog->sec_name, *attach_name; + const struct bpf_sec_def *sec = NULL; int i, err; if (!name) @@ -8884,17 +8928,37 @@ static int libbpf_find_attach_btf_id(struct bpf_program *prog) continue; if (strncmp(name, section_defs[i].sec, section_defs[i].len)) continue; - if (attach_prog_fd) - err = libbpf_find_prog_btf_id(name + section_defs[i].len, - attach_prog_fd); - else - err = __find_vmlinux_btf_id(prog->obj->btf_vmlinux, - name + section_defs[i].len, - attach_type); + + sec = §ion_defs[i]; + break; + } + + if (!sec) { + pr_warn("failed to identify BTF ID based on ELF section name '%s'\n", name); + return -ESRCH; + } + attach_name = name + sec->len; + + /* BPF program's BTF ID */ + if (attach_prog_fd) { + err = libbpf_find_prog_btf_id(attach_name, attach_prog_fd); + if (err < 0) { + pr_warn("failed to find BPF program (FD %d) BTF ID for '%s': %d\n", + attach_prog_fd, attach_name, err); + return err; + } + *btf_obj_id = 0; + *btf_type_id = err; + return 0; + } + + /* kernel/module BTF ID */ + err = find_kernel_btf_id(prog->obj, attach_name, attach_type, btf_obj_id, btf_type_id); + if (err) { + pr_warn("failed to find kernel BTF type ID of '%s': %d\n", attach_name, err); return err; } - pr_warn("failed to identify btf_id based on ELF section name '%s'\n", name); - return -ESRCH; + return 0; } int libbpf_attach_type_by_name(const char *name, @@ -10783,6 +10847,7 @@ int bpf_program__set_attach_target(struct bpf_program *prog, return btf_id; prog->attach_btf_id = btf_id; + prog->attach_btf_obj_id = 0; prog->attach_prog_fd = attach_prog_fd; return 0; } diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h index 681073a67ae3..36236b4430ff 100644 --- a/tools/lib/bpf/libbpf_internal.h +++ b/tools/lib/bpf/libbpf_internal.h @@ -160,6 +160,7 @@ struct bpf_prog_load_params { const char *license; __u32 kern_version; __u32 attach_prog_fd; + __u32 attach_btf_obj_id; __u32 attach_btf_id; __u32 prog_ifindex; __u32 prog_btf_fd;