From patchwork Wed Jun 28 11:53:27 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yafang Shao X-Patchwork-Id: 13295631 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 C674BEB64DD for ; Wed, 28 Jun 2023 11:54:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231515AbjF1LyA (ORCPT ); Wed, 28 Jun 2023 07:54:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37322 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231636AbjF1Lxv (ORCPT ); Wed, 28 Jun 2023 07:53:51 -0400 Received: from mail-oa1-x30.google.com (mail-oa1-x30.google.com [IPv6:2001:4860:4864:20::30]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EA01D30C7; Wed, 28 Jun 2023 04:53:49 -0700 (PDT) Received: by mail-oa1-x30.google.com with SMTP id 586e51a60fabf-1b06777596cso1318721fac.2; Wed, 28 Jun 2023 04:53:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1687953229; x=1690545229; 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=fk/OgVSuBVSulryq84Ay+2pCg6rhn1wZZVYD4NzZU2A=; b=MxKHaKqnUcTB6iLObqRa+sVfjy4ZksBpxfOuPfyyQl4ZzD6dbfab0EfSo5SE5NxCbs SyRm3544wtRwPiwTjJ/KwZY7wcLFGfPTHs9P3Ef1dUVH3/DFbuz/+XG210fp3NiceR8k DFI264ulRUhapngpcfiCknrqvPmbd63V+wNPa3gkxSAc7h1NcptcibsFwe98QVnEPBYO 5qGxyS77YGgZRUELJEePSm+kVt8qU/7zBIRWW1NRtPEdnyec7EGP6PaN/5tlsWPIneYH SmlQzA659jAc1AG8pTs5qj7Ge9MfiyR3XfzrdGdV2C/3hQvDT+FrSYmjLIydU2PDvTZ5 svBw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1687953229; x=1690545229; 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=fk/OgVSuBVSulryq84Ay+2pCg6rhn1wZZVYD4NzZU2A=; b=PkhV1V7azLRMMak1M+UeWAMotqMBzTZXrShd4x0HwZncnPTHjSQE/DF+KQSoKBsr/1 WyRuKshPow0INBjAD7l3Eq/8ypTyMyGMQ+00X+yyjc1Sd/NEOi+P3LctQgn9qH+qh/Qr zls6AjqxPUwnGOuCaDWSDBDiA4T98Ls5SPLlWbQ697LzQhlHzDTzXKx8rO7OkWoOmQzw iw2bk/brsziMoxykEi4793KS98+H2gyK8YEGF4UaCsdRMfsC9Ks2I7kgMuBnC2ZccBS8 G+g5eLr3U2E0736nTAswCMv3SDMf71prVrm1I+IUsrskQAmfnolDCOMzADikUc0W5IJ4 W2lg== X-Gm-Message-State: AC+VfDxkTR2cOLuRNKsDzPbQjZgun6J2niYqp5h3J2KLdEYVFAuyvN0w enT/CEa5j3KBxbHPgph+oNE= X-Google-Smtp-Source: ACHHUZ7nqri6c/ZmzA0lWbH9C0bsmH0C5EJwSJNlKoPiT/I1TQ6QwhyFzvLST1YO4AozRbbCT6rhew== X-Received: by 2002:a05:6870:9444:b0:1ad:4d4:3104 with SMTP id e4-20020a056870944400b001ad04d43104mr20511459oal.38.1687953229132; Wed, 28 Jun 2023 04:53:49 -0700 (PDT) Received: from vultr.guest ([2001:19f0:ac02:b79:5400:4ff:fe7d:3e26]) by smtp.gmail.com with ESMTPSA id n91-20020a17090a5ae400b002471deb13fcsm8000504pji.6.2023.06.28.04.53.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 28 Jun 2023 04:53:48 -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 v6 bpf-next 09/11] bpf: Support ->fill_link_info for perf_event Date: Wed, 28 Jun 2023 11:53:27 +0000 Message-Id: <20230628115329.248450-10-laoar.shao@gmail.com> X-Mailer: git-send-email 2.39.3 In-Reply-To: <20230628115329.248450-1-laoar.shao@gmail.com> References: <20230628115329.248450-1-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 | 35 ++++++++++ kernel/bpf/syscall.c | 117 +++++++++++++++++++++++++++++++++ tools/include/uapi/linux/bpf.h | 35 ++++++++++ 3 files changed, 187 insertions(+) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 512ba3ba2ed3..7efe51672c15 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -1057,6 +1057,16 @@ 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_URETPROBE = 2, + BPF_PERF_EVENT_KPROBE = 3, + BPF_PERF_EVENT_KRETPROBE = 4, + BPF_PERF_EVENT_TRACEPOINT = 5, + BPF_PERF_EVENT_EVENT = 6, +}; + /* cgroup-bpf attach flags used in BPF_PROG_ATTACH command * * NONE(default): No further bpf programs allowed in the subtree. @@ -6444,6 +6454,31 @@ struct bpf_link_info { __u32 count; __u32 flags; } kprobe_multi; + struct { + __u32 type; /* enum bpf_perf_event_type */ + __u32 :32; + union { + struct { + __aligned_u64 file_name; /* in/out */ + __u32 name_len; + __u32 offset;/* offset from file_name */ + } uprobe; /* BPF_PERF_EVENT_UPROBE, BPF_PERF_EVENT_URETPROBE */ + struct { + __aligned_u64 func_name; /* in/out */ + __u32 name_len; + __u32 offset;/* offset from func_name */ + __u64 addr; + } kprobe; /* BPF_PERF_EVENT_KPROBE, BPF_PERF_EVENT_KRETPROBE */ + 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 72de91beabbc..05ff0a560f1a 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -3398,9 +3398,126 @@ 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; + err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr, + &type); + if (err) + return err; + if (type == BPF_FD_TYPE_KRETPROBE) + info->perf_event.type = BPF_PERF_EVENT_KRETPROBE; + else + info->perf_event.type = BPF_PERF_EVENT_KPROBE; + + info->perf_event.kprobe.offset = offset; + if (!kallsyms_show_value(current_cred())) + addr = 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; + err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr, + &type); + if (err) + return err; + + if (type == BPF_FD_TYPE_URETPROBE) + info->perf_event.type = BPF_PERF_EVENT_URETPROBE; + else + info->perf_event.type = BPF_PERF_EVENT_UPROBE; + info->perf_event.uprobe.offset = offset; + 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 512ba3ba2ed3..7efe51672c15 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -1057,6 +1057,16 @@ 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_URETPROBE = 2, + BPF_PERF_EVENT_KPROBE = 3, + BPF_PERF_EVENT_KRETPROBE = 4, + BPF_PERF_EVENT_TRACEPOINT = 5, + BPF_PERF_EVENT_EVENT = 6, +}; + /* cgroup-bpf attach flags used in BPF_PROG_ATTACH command * * NONE(default): No further bpf programs allowed in the subtree. @@ -6444,6 +6454,31 @@ struct bpf_link_info { __u32 count; __u32 flags; } kprobe_multi; + struct { + __u32 type; /* enum bpf_perf_event_type */ + __u32 :32; + union { + struct { + __aligned_u64 file_name; /* in/out */ + __u32 name_len; + __u32 offset;/* offset from file_name */ + } uprobe; /* BPF_PERF_EVENT_UPROBE, BPF_PERF_EVENT_URETPROBE */ + struct { + __aligned_u64 func_name; /* in/out */ + __u32 name_len; + __u32 offset;/* offset from func_name */ + __u64 addr; + } kprobe; /* BPF_PERF_EVENT_KPROBE, BPF_PERF_EVENT_KRETPROBE */ + 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)));