From patchwork Tue Jun 20 16:30:06 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yafang Shao X-Patchwork-Id: 13286168 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 CD96BEB64DB for ; Tue, 20 Jun 2023 16:30:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231563AbjFTQak (ORCPT ); Tue, 20 Jun 2023 12:30:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56348 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231492AbjFTQag (ORCPT ); Tue, 20 Jun 2023 12:30:36 -0400 Received: from mail-pg1-x52e.google.com (mail-pg1-x52e.google.com [IPv6:2607:f8b0:4864:20::52e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 34E9D100; Tue, 20 Jun 2023 09:30:35 -0700 (PDT) Received: by mail-pg1-x52e.google.com with SMTP id 41be03b00d2f7-517bdc9e81dso1994467a12.1; Tue, 20 Jun 2023 09:30:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1687278633; x=1689870633; 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=yqvY4jtEfZYloFEPW7IsonK2EHfV4D55HFqHyhzZqMg=; b=fbPnzUhB9Swfydfk5XqM3+BdUViF1cTQ5fd3BIrCRnQGvJTRgJ3Ls4HWQ9nnIxTLUi ytlbC3aKLUrVrHh23W8GnzPm7navXtjySiP4126iatbd8b5yb9hxrZGoa2r/9w6oXUpP AT0akfnFcVVFV4pubbtwswzhVswNGSueW1bDiRgx0+5tIKEcamIS8jcHS+vf42sJto43 xBSNbDIBeVExPkCdfX4y8JDKoQ1p3+ZtEWjTwK+YqnKpmVLSDr5xpDTA7sJiERL/NJnd N6YCdKrqSB6aYeTI0Y7vQDI+7qmTGwVpGoB74GVyGEMqIrcl4wawsu+g+M2J6AjuRfZw F6sQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1687278633; x=1689870633; 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=yqvY4jtEfZYloFEPW7IsonK2EHfV4D55HFqHyhzZqMg=; b=lKz7s+NoOCX2b+rf+xkS2fEK/9JzinslAN6mSiSF6Bc8DeHAZSUDvb8EB6kGc5/i5a 1O6Pi/8o765dZrM7j0RV/VY+3pclIGIM0yasKO/uw9Bwx2shjvG3UogGhwg0R//q1tJF O95jlR/wl5ZeP51W5fxSjz9xwEKibpNBDHd+pRd6jtyOUg+e8yQ2EmOUWf25OzVfVYIo ZLjMV8n8ulrkUP6WXDP/i8n+eKkfyEINcCaqwdZWqI0Dlx3cnDrGKadfhsYU8yWDaS+g +T5QzQizW4Omh1szvZx7LiZQaSs4BtsBDBGLwo8DwLOsZR5eHDpqLE4SlCNSCBLEFR40 DzAg== X-Gm-Message-State: AC+VfDyizJgPGsBWtHNgNrv/wgyfDqoA/mxBy7LquVIkpliWY5oH8ygL 54DfNo58HjWVC/hdziMYcbyy4SOPkYzfMW5YalI= X-Google-Smtp-Source: ACHHUZ6zN2FE4qcW4XBcsOL7YnoH1yERLmxdsJnyoNkoHN1j6NZysQUhZKF6HHzPl+A/HsDEjOvL4A== X-Received: by 2002:a17:90b:33c4:b0:25e:b9fc:7e0c with SMTP id lk4-20020a17090b33c400b0025eb9fc7e0cmr9971809pjb.45.1687278633524; Tue, 20 Jun 2023 09:30:33 -0700 (PDT) Received: from vultr.guest ([2001:19f0:ac02:b96:5400:4ff:fe7b:3b23]) by smtp.gmail.com with ESMTPSA id t8-20020a17090a3b4800b0025c1cfdb93esm1854286pjf.13.2023.06.20.09.30.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 20 Jun 2023 09:30:32 -0700 (PDT) From: Yafang Shao To: ast@kernel.org, daniel@iogearbox.net, john.fastabend@gmail.com, andrii@kernel.org, martin.lau@linux.dev, song@kernel.org, yhs@fb.com, kpsingh@kernel.org, sdf@google.com, haoluo@google.com, jolsa@kernel.org, quentin@isovalent.com, rostedt@goodmis.org, mhiramat@kernel.org Cc: bpf@vger.kernel.org, linux-trace-kernel@vger.kernel.org, Yafang Shao Subject: [PATCH v4 bpf-next 09/11] bpf: Support ->fill_link_info for perf_event Date: Tue, 20 Jun 2023 16:30:06 +0000 Message-Id: <20230620163008.3718-10-laoar.shao@gmail.com> X-Mailer: git-send-email 2.39.3 In-Reply-To: <20230620163008.3718-1-laoar.shao@gmail.com> References: <20230620163008.3718-1-laoar.shao@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-trace-kernel@vger.kernel.org By introducing support for ->fill_link_info to the perf_event link, users gain the ability to inspect it using `bpftool link show`. While the current approach involves accessing this information via `bpftool perf show`, consolidating link information for all link types in one place offers greater convenience. Additionally, this patch extends support to the generic perf event, which is not currently accommodated by `bpftool perf show`. While only the perf type and config are exposed to userspace, other attributes such as sample_period and sample_freq are ignored. It's important to note that if kptr_restrict is not permitted, the probed address will not be exposed, maintaining security measures. A new enum bpf_perf_event_type is introduced to help the user understand which struct is relevant. Signed-off-by: Yafang Shao --- include/uapi/linux/bpf.h | 36 +++++++++++++ kernel/bpf/syscall.c | 115 +++++++++++++++++++++++++++++++++++++++++ tools/include/uapi/linux/bpf.h | 36 +++++++++++++ 3 files changed, 187 insertions(+) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 23691ea..56528dd 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -1056,6 +1056,16 @@ enum bpf_link_type { MAX_BPF_LINK_TYPE, }; +enum bpf_perf_event_type { + BPF_PERF_EVENT_UNSPEC = 0, + BPF_PERF_EVENT_UPROBE = 1, + BPF_PERF_EVENT_KPROBE = 2, + BPF_PERF_EVENT_TRACEPOINT = 3, + BPF_PERF_EVENT_EVENT = 4, + + MAX_BPF_PERF_EVENT_TYPE, +}; + /* cgroup-bpf attach flags used in BPF_PROG_ATTACH command * * NONE(default): No further bpf programs allowed in the subtree. @@ -6443,6 +6453,32 @@ struct bpf_link_info { __u32 count; __u32 flags; } kprobe_multi; + struct { + __u32 type; /* enum bpf_perf_event_type */ + union { + struct { + __aligned_u64 file_name; /* in/out */ + __u32 name_len; + __u32 offset;/* offset from file_name */ + __u32 flags; + } uprobe; /* BPF_PERF_EVENT_UPROBE */ + struct { + __aligned_u64 func_name; /* in/out */ + __u32 name_len; + __u32 offset;/* offset from func_name */ + __u64 addr; + __u32 flags; + } kprobe; /* BPF_PERF_EVENT_KPROBE */ + struct { + __aligned_u64 tp_name; /* in/out */ + __u32 name_len; + } tracepoint; /* BPF_PERF_EVENT_TRACEPOINT */ + struct { + __u64 config; + __u32 type; + } event; /* BPF_PERF_EVENT_EVENT */ + }; + } perf_event; }; } __attribute__((aligned(8))); diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index db9b500..9f8d378 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -3340,9 +3340,124 @@ static int bpf_perf_link_fill_common(const struct perf_event *event, return 0; } +#ifdef CONFIG_KPROBE_EVENTS +static int bpf_perf_link_fill_kprobe(const struct perf_event *event, + struct bpf_link_info *info) +{ + char __user *uname; + u64 addr, offset; + u32 ulen, type; + int err; + + uname = u64_to_user_ptr(info->perf_event.kprobe.func_name); + ulen = info->perf_event.kprobe.name_len; + info->perf_event.type = BPF_PERF_EVENT_KPROBE; + err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr, + &type); + if (err) + return err; + + info->perf_event.kprobe.offset = offset; + if (type == BPF_FD_TYPE_KRETPROBE) + info->perf_event.kprobe.flags = 1; + if (!kallsyms_show_value(current_cred())) + return 0; + info->perf_event.kprobe.addr = addr; + return 0; +} +#endif + +#ifdef CONFIG_UPROBE_EVENTS +static int bpf_perf_link_fill_uprobe(const struct perf_event *event, + struct bpf_link_info *info) +{ + char __user *uname; + u64 addr, offset; + u32 ulen, type; + int err; + + uname = u64_to_user_ptr(info->perf_event.uprobe.file_name); + ulen = info->perf_event.uprobe.name_len; + info->perf_event.type = BPF_PERF_EVENT_UPROBE; + err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr, + &type); + if (err) + return err; + + info->perf_event.uprobe.offset = offset; + if (type == BPF_FD_TYPE_URETPROBE) + info->perf_event.uprobe.flags = 1; + return 0; +} +#endif + +static int bpf_perf_link_fill_probe(const struct perf_event *event, + struct bpf_link_info *info) +{ +#ifdef CONFIG_KPROBE_EVENTS + if (event->tp_event->flags & TRACE_EVENT_FL_KPROBE) + return bpf_perf_link_fill_kprobe(event, info); +#endif +#ifdef CONFIG_UPROBE_EVENTS + if (event->tp_event->flags & TRACE_EVENT_FL_UPROBE) + return bpf_perf_link_fill_uprobe(event, info); +#endif + return -EOPNOTSUPP; +} + +static int bpf_perf_link_fill_tracepoint(const struct perf_event *event, + struct bpf_link_info *info) +{ + char __user *uname; + u64 addr, offset; + u32 ulen, type; + + uname = u64_to_user_ptr(info->perf_event.tracepoint.tp_name); + ulen = info->perf_event.tracepoint.name_len; + info->perf_event.type = BPF_PERF_EVENT_TRACEPOINT; + return bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr, + &type); +} + +static int bpf_perf_link_fill_perf_event(const struct perf_event *event, + struct bpf_link_info *info) +{ + info->perf_event.event.type = event->attr.type; + info->perf_event.event.config = event->attr.config; + info->perf_event.type = BPF_PERF_EVENT_EVENT; + return 0; +} + +static int bpf_perf_link_fill_link_info(const struct bpf_link *link, + struct bpf_link_info *info) +{ + struct bpf_perf_link *perf_link; + const struct perf_event *event; + + perf_link = container_of(link, struct bpf_perf_link, link); + event = perf_get_event(perf_link->perf_file); + if (IS_ERR(event)) + return PTR_ERR(event); + + if (!event->prog) + return -EINVAL; + + switch (event->prog->type) { + case BPF_PROG_TYPE_PERF_EVENT: + return bpf_perf_link_fill_perf_event(event, info); + case BPF_PROG_TYPE_TRACEPOINT: + return bpf_perf_link_fill_tracepoint(event, info); + case BPF_PROG_TYPE_KPROBE: + return bpf_perf_link_fill_probe(event, info); + default: + return -EOPNOTSUPP; + } +} + static const struct bpf_link_ops bpf_perf_link_lops = { .release = bpf_perf_link_release, .dealloc = bpf_perf_link_dealloc, + .fill_link_info = bpf_perf_link_fill_link_info, }; static int bpf_perf_link_attach(const union bpf_attr *attr, struct bpf_prog *prog) diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 23691ea..56528dd 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -1056,6 +1056,16 @@ enum bpf_link_type { MAX_BPF_LINK_TYPE, }; +enum bpf_perf_event_type { + BPF_PERF_EVENT_UNSPEC = 0, + BPF_PERF_EVENT_UPROBE = 1, + BPF_PERF_EVENT_KPROBE = 2, + BPF_PERF_EVENT_TRACEPOINT = 3, + BPF_PERF_EVENT_EVENT = 4, + + MAX_BPF_PERF_EVENT_TYPE, +}; + /* cgroup-bpf attach flags used in BPF_PROG_ATTACH command * * NONE(default): No further bpf programs allowed in the subtree. @@ -6443,6 +6453,32 @@ struct bpf_link_info { __u32 count; __u32 flags; } kprobe_multi; + struct { + __u32 type; /* enum bpf_perf_event_type */ + union { + struct { + __aligned_u64 file_name; /* in/out */ + __u32 name_len; + __u32 offset;/* offset from file_name */ + __u32 flags; + } uprobe; /* BPF_PERF_EVENT_UPROBE */ + struct { + __aligned_u64 func_name; /* in/out */ + __u32 name_len; + __u32 offset;/* offset from func_name */ + __u64 addr; + __u32 flags; + } kprobe; /* BPF_PERF_EVENT_KPROBE */ + struct { + __aligned_u64 tp_name; /* in/out */ + __u32 name_len; + } tracepoint; /* BPF_PERF_EVENT_TRACEPOINT */ + struct { + __u64 config; + __u32 type; + } event; /* BPF_PERF_EVENT_EVENT */ + }; + } perf_event; }; } __attribute__((aligned(8)));