From patchwork Tue Feb 21 02:53:45 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Menglong Dong X-Patchwork-Id: 13147333 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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4B306C64ED9 for ; Tue, 21 Feb 2023 02:55:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233356AbjBUCzV (ORCPT ); Mon, 20 Feb 2023 21:55:21 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60906 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233461AbjBUCzB (ORCPT ); Mon, 20 Feb 2023 21:55:01 -0500 Received: from mail-pl1-x641.google.com (mail-pl1-x641.google.com [IPv6:2607:f8b0:4864:20::641]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8494D2D57; Mon, 20 Feb 2023 18:54:36 -0800 (PST) Received: by mail-pl1-x641.google.com with SMTP id bh1so3524290plb.11; Mon, 20 Feb 2023 18:54:36 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=PUWQmp5W8Kb/uIgiFWjF+mchWuzL4yG/Sn9X8F8cwr0=; b=MNnplTUEN5wJIC1J7wEdQVJ5LmKkg3rvaRnqaZre5mNRTB6eSvNrhFdD0akR2cxhtg qs6YKupDOOWPPaP85cXB7JIw8iVJaWISA5JwEnsmDSzeDQ1zQ4yD6kpqUqpSqCEGb5iI bFTMXiaMjgK8889+RMtdbD63y/N/XX/VUpiaA43acdWMKOnQMSqkLw9LvYsjl5upPQW8 Jem43AWYhJYcHTL2cNy85bs5hDi8UVe8vrg0PlsYsVXXofo4wzadpmvZyHYQsF33ao89 cR7+VhHNs9c/2Dvy2mtE2YfKkOaObGE61G59nMJoRpv4+bM6cmk0F4W7KHVvrHXmwosT 3jGg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=PUWQmp5W8Kb/uIgiFWjF+mchWuzL4yG/Sn9X8F8cwr0=; b=zfBoYCXuB+1s4BxhbdukAhFbbyICseCCtEEQM01FGI5MxDZ9UjRN5s//lpj6JCMHd+ XFYwvvSxucnTEThqUX7t0s76lPgCb9Or6RGCKbM6N+ZuJXQ2mEmXWZcbMtWnoJ1l39w/ 2Q1GBf6STAzpquSXEgevHXvrlIUWs+pTy9ZXttDCuHkkp6bZD804pQBiStT+eViJn5XX fs+nkFtIop4tQ90YYB4qE+uZaVyrkwsQx+vsnj7n6at7PPq1gHizF2Mp5POpAEcaHfLs +yhUv2fxC7qMY04A9whVjCpfX4hmuc7ua1Jr+fXjsoGUWBDn0mHuqR+E41yqbRKeebfz KX8A== X-Gm-Message-State: AO0yUKWieGqeDnJ6RcTmyrBP3Zrd1i+/DZUiSQ2tmD7/72GHGhV08QMC jkrv/LXNPlUqG28mVjK1ZTE= X-Google-Smtp-Source: AK7set+KEvKlHyUDq0SyBMWLid2Dd4t0MSywmg9svJudMZzxx0JQwoYBvy/MXAHwnfPw5j1wgXf++Q== X-Received: by 2002:a17:903:18e:b0:19a:5933:936e with SMTP id z14-20020a170903018e00b0019a5933936emr6947129plg.38.1676948071724; Mon, 20 Feb 2023 18:54:31 -0800 (PST) Received: from localhost.localdomain ([203.205.141.16]) by smtp.gmail.com with ESMTPSA id k3-20020a170902e90300b0019a837be977sm8590156pld.271.2023.02.20.18.54.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 20 Feb 2023 18:54:31 -0800 (PST) From: menglong8.dong@gmail.com X-Google-Original-From: imagedong@tencent.com To: andrii.nakryiko@gmail.com, alan.maguire@oracle.com Cc: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, martin.lau@linux.dev, song@kernel.org, yhs@fb.com, john.fastabend@gmail.com, kpsingh@kernel.org, sdf@google.com, haoluo@google.com, jolsa@kernel.org, benbjiang@tencent.com, bpf@vger.kernel.org, linux-kernel@vger.kernel.org, Menglong Dong Subject: [PATCH bpf-next v3 1/3] libbpf: add support to set kprobe/uprobe attach mode Date: Tue, 21 Feb 2023 10:53:45 +0800 Message-Id: <20230221025347.389047-2-imagedong@tencent.com> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20230221025347.389047-1-imagedong@tencent.com> References: <20230221025347.389047-1-imagedong@tencent.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net From: Menglong Dong By default, libbpf will attach the kprobe/uprobe eBPF program in the latest mode that supported by kernel. In this patch, we add the support to let users manually attach kprobe/uprobe in legacy or perf mode. There are 3 mode that supported by the kernel to attach kprobe/uprobe: LEGACY: create perf event in legacy way and don't use bpf_link PERF: create perf event with perf_event_open() and don't use bpf_link LINK: create perf event with perf_event_open() and use bpf_link Users now can manually choose the mode with bpf_program__attach_uprobe_opts()/bpf_program__attach_kprobe_opts(). Link: https://lore.kernel.org/bpf/20230113093427.1666466-1-imagedong@tencent.com/ Reviewed-by: Biao Jiang Signed-off-by: Menglong Dong Reviewed-by: Alan Maguire --- v2: - rename no_link to force_ioctl_attach - rename probe_mode to probe_attach_mode - add more doc for probe_attach_mode - return -ENOTSUP when necessray in bpf_program__attach_uprobe_opts and bpf_program__attach_kprobe_opts --- tools/lib/bpf/libbpf.c | 42 +++++++++++++++++++++++++++++++++++++++++- tools/lib/bpf/libbpf.h | 31 ++++++++++++++++++++++++++++--- 2 files changed, 69 insertions(+), 4 deletions(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 05c4db355f28..d07a0d7b9edd 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -9747,7 +9747,7 @@ struct bpf_link *bpf_program__attach_perf_event_opts(const struct bpf_program *p link->link.dealloc = &bpf_link_perf_dealloc; link->perf_event_fd = pfd; - if (kernel_supports(prog->obj, FEAT_PERF_LINK)) { + if (kernel_supports(prog->obj, FEAT_PERF_LINK) && !opts->force_ioctl_attach) { DECLARE_LIBBPF_OPTS(bpf_link_create_opts, link_opts, .perf_event.bpf_cookie = OPTS_GET(opts, bpf_cookie, 0)); @@ -10106,6 +10106,7 @@ bpf_program__attach_kprobe_opts(const struct bpf_program *prog, const struct bpf_kprobe_opts *opts) { DECLARE_LIBBPF_OPTS(bpf_perf_event_opts, pe_opts); + enum probe_attach_mode attach_mode; char errmsg[STRERR_BUFSIZE]; char *legacy_probe = NULL; struct bpf_link *link; @@ -10116,11 +10117,30 @@ bpf_program__attach_kprobe_opts(const struct bpf_program *prog, if (!OPTS_VALID(opts, bpf_kprobe_opts)) return libbpf_err_ptr(-EINVAL); + attach_mode = OPTS_GET(opts, attach_mode, PROBE_ATTACH_MODE_DEFAULT); retprobe = OPTS_GET(opts, retprobe, false); offset = OPTS_GET(opts, offset, 0); pe_opts.bpf_cookie = OPTS_GET(opts, bpf_cookie, 0); legacy = determine_kprobe_perf_type() < 0; + switch (attach_mode) { + case PROBE_ATTACH_MODE_LEGACY: + legacy = true; + pe_opts.force_ioctl_attach = true; + break; + case PROBE_ATTACH_MODE_PERF: + if (legacy) + return libbpf_err_ptr(-ENOTSUP); + pe_opts.force_ioctl_attach = true; + break; + case PROBE_ATTACH_MODE_LINK: + if (!kernel_supports(prog->obj, FEAT_PERF_LINK)) + return libbpf_err_ptr(-ENOTSUP); + break; + default: + break; + } + if (!legacy) { pfd = perf_event_open_probe(false /* uprobe */, retprobe, func_name, offset, @@ -10774,6 +10794,7 @@ bpf_program__attach_uprobe_opts(const struct bpf_program *prog, pid_t pid, { DECLARE_LIBBPF_OPTS(bpf_perf_event_opts, pe_opts); char errmsg[STRERR_BUFSIZE], *legacy_probe = NULL; + enum probe_attach_mode attach_mode; char full_binary_path[PATH_MAX]; struct bpf_link *link; size_t ref_ctr_off; @@ -10784,6 +10805,7 @@ bpf_program__attach_uprobe_opts(const struct bpf_program *prog, pid_t pid, if (!OPTS_VALID(opts, bpf_uprobe_opts)) return libbpf_err_ptr(-EINVAL); + attach_mode = OPTS_GET(opts, attach_mode, PROBE_ATTACH_MODE_DEFAULT); retprobe = OPTS_GET(opts, retprobe, false); ref_ctr_off = OPTS_GET(opts, ref_ctr_offset, 0); pe_opts.bpf_cookie = OPTS_GET(opts, bpf_cookie, 0); @@ -10812,6 +10834,24 @@ bpf_program__attach_uprobe_opts(const struct bpf_program *prog, pid_t pid, } legacy = determine_uprobe_perf_type() < 0; + switch (attach_mode) { + case PROBE_ATTACH_MODE_LEGACY: + legacy = true; + pe_opts.force_ioctl_attach = true; + break; + case PROBE_ATTACH_MODE_PERF: + if (legacy) + return libbpf_err_ptr(-ENOTSUP); + pe_opts.force_ioctl_attach = true; + break; + case PROBE_ATTACH_MODE_LINK: + if (!kernel_supports(prog->obj, FEAT_PERF_LINK)) + return libbpf_err_ptr(-ENOTSUP); + break; + default: + break; + } + if (!legacy) { pfd = perf_event_open_probe(true /* uprobe */, retprobe, binary_path, func_offset, pid, ref_ctr_off); diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h index 2efd80f6f7b9..ef8f68da42f9 100644 --- a/tools/lib/bpf/libbpf.h +++ b/tools/lib/bpf/libbpf.h @@ -451,8 +451,11 @@ struct bpf_perf_event_opts { size_t sz; /* custom user-provided value fetchable through bpf_get_attach_cookie() */ __u64 bpf_cookie; + /* don't use bpf_link when attach eBPF program */ + bool force_ioctl_attach; + size_t :0; }; -#define bpf_perf_event_opts__last_field bpf_cookie +#define bpf_perf_event_opts__last_field force_ioctl_attach LIBBPF_API struct bpf_link * bpf_program__attach_perf_event(const struct bpf_program *prog, int pfd); @@ -461,6 +464,24 @@ LIBBPF_API struct bpf_link * bpf_program__attach_perf_event_opts(const struct bpf_program *prog, int pfd, const struct bpf_perf_event_opts *opts); + +/** + * enum probe_attach_mode - the mode to attach kprobe/uprobe + * + * force libbpf to attach kprobe/uprobe in specific mode, -ENOTSUP will + * be returned if it is not supported by the kernel. + */ +enum probe_attach_mode { + /* attach probe in latest supported mode by kernel */ + PROBE_ATTACH_MODE_DEFAULT = 0, + /* attach probe in legacy mode */ + PROBE_ATTACH_MODE_LEGACY, + /* create perf event with perf_event_open() syscall */ + PROBE_ATTACH_MODE_PERF, + /* attach probe with bpf_link */ + PROBE_ATTACH_MODE_LINK, +}; + struct bpf_kprobe_opts { /* size of this struct, for forward/backward compatiblity */ size_t sz; @@ -470,9 +491,11 @@ struct bpf_kprobe_opts { size_t offset; /* kprobe is return probe */ bool retprobe; + /* kprobe attach mode */ + enum probe_attach_mode attach_mode; size_t :0; }; -#define bpf_kprobe_opts__last_field retprobe +#define bpf_kprobe_opts__last_field attach_mode LIBBPF_API struct bpf_link * bpf_program__attach_kprobe(const struct bpf_program *prog, bool retprobe, @@ -570,9 +593,11 @@ struct bpf_uprobe_opts { * binary_path. */ const char *func_name; + /* uprobe attach mode */ + enum probe_attach_mode attach_mode; size_t :0; }; -#define bpf_uprobe_opts__last_field func_name +#define bpf_uprobe_opts__last_field attach_mode /** * @brief **bpf_program__attach_uprobe()** attaches a BPF program