From patchwork Thu Jun 8 10:35:20 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yafang Shao X-Patchwork-Id: 13271914 X-Patchwork-Delegate: bpf@iogearbox.net Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5FB22C8FD for ; Thu, 8 Jun 2023 10:35:46 +0000 (UTC) Received: from mail-qv1-xf2b.google.com (mail-qv1-xf2b.google.com [IPv6:2607:f8b0:4864:20::f2b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DB0882103 for ; Thu, 8 Jun 2023 03:35:43 -0700 (PDT) Received: by mail-qv1-xf2b.google.com with SMTP id 6a1803df08f44-62b671e0a0dso3978866d6.1 for ; Thu, 08 Jun 2023 03:35:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1686220543; x=1688812543; 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=N6mSN8B6rsVi3+V/BwBxx2tAFIVmO4m7KApI1B2488Y=; b=Uv8iwfGoBk1QqMFIGFV4fZtuWB+MbOtXzsvW3Rr3VmEaDqNjgTW9uJt0uu4jLL2GJO x23Wl7RMSFZgAjziwgLiJa/WkBdSnipDuZucT8a9Aiov+46u50/+Pilx7popSbt3ZLbm QyZZb9/GBF6JODHxnU+lUyO5rM3+IiTHJNdyU+aue59IU9ftiV9qG2klu8GJAUZgieID cSMMDZpn8w3l7NGqV+RuGiqUUtTuNI+wN//1AAgnOYC/YMxU+MgOjpqeeVLWvm7NItiP t46maIGX8Q9BrE9MATNyE5FSHIg483rKNpSXxK1GYvDFy2qF7BEayXltzd8fosVpTBjs exHQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1686220543; x=1688812543; 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=N6mSN8B6rsVi3+V/BwBxx2tAFIVmO4m7KApI1B2488Y=; b=fknGktU05SqYYsAuDg0XF6RQLwVT7JXQARbuatUcAR45nWy6jEMKJYxWyr8aUnBJ8b 1NXdJcxWfAp4CKlIcMxIkkqsXqopLoQgDk0xi6aijT8x/Kq6J7zA/hVNZmRTQPh+H+Y7 GS2SxG+caldASJhqhTDFgu5+3IyJCd3SDBYwL6ZiB3eC8iMqe6MOGyhTTRAx1IDR4cyy C+EgenEslPif1A3HvQYxGL4Qvzd4k5b2ihieWQA1ydRsuz2TgHJD9/MC0C2b1FIhyFA2 KUiuxW/zl0WvRYUZ+7vK3WpbC7r2c7tBmEzW5iFb89QVAg3MEJj3GcHZbnUPZ5zIgKPv LjZg== X-Gm-Message-State: AC+VfDwKgmzArMpczhuHEQ14diE8o8lSOabPL8M+CW+CYvqo4aAzXuc2 Bim6xR4WspuN1ChHyvhKjig= X-Google-Smtp-Source: ACHHUZ7gn7CBkRWcMSIJsIOvGE8yzT1u0xjBmK7w8q8wbGAoye5PUAosZv3TeNwiGUx98YrUKtq/+w== X-Received: by 2002:ad4:5964:0:b0:616:5460:aafd with SMTP id eq4-20020ad45964000000b006165460aafdmr1163428qvb.3.1686220542910; Thu, 08 Jun 2023 03:35:42 -0700 (PDT) Received: from vultr.guest ([2001:19f0:1000:2418:5400:4ff:fe77:b548]) by smtp.gmail.com with ESMTPSA id p16-20020a0cf550000000b0062839fc6e36sm302714qvm.70.2023.06.08.03.35.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 08 Jun 2023 03:35:42 -0700 (PDT) From: Yafang Shao To: 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, quentin@isovalent.com Cc: bpf@vger.kernel.org, Yafang Shao Subject: [PATCH v2 bpf-next 08/11] bpf: Support ->fill_link_info for perf_event Date: Thu, 8 Jun 2023 10:35:20 +0000 Message-Id: <20230608103523.102267-9-laoar.shao@gmail.com> X-Mailer: git-send-email 2.39.3 In-Reply-To: <20230608103523.102267-1-laoar.shao@gmail.com> References: <20230608103523.102267-1-laoar.shao@gmail.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FREEMAIL_FROM, RCVD_IN_DNSWL_NONE,SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net X-Patchwork-Delegate: bpf@iogearbox.net 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 set to 2, the probed address will not be exposed, maintaining security measures. Signed-off-by: Yafang Shao --- include/uapi/linux/bpf.h | 22 ++++++++++ kernel/bpf/syscall.c | 98 ++++++++++++++++++++++++++++++++++++++++++ tools/include/uapi/linux/bpf.h | 22 ++++++++++ 3 files changed, 142 insertions(+) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index d99cc16..c3b821d 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -6443,6 +6443,28 @@ struct bpf_link_info { __u32 count; __u8 retprobe; } kprobe_multi; + union { + struct { + /* The name is: + * a) uprobe: file name + * b) kprobe: kernel function + */ + __aligned_u64 name; /* in/out: name buffer ptr */ + __u32 name_len; + __u32 offset; /* offset from the name */ + __u64 addr; + __u8 retprobe; + } probe; /* uprobe, kprobe */ + struct { + /* in/out: tracepoint name buffer ptr */ + __aligned_u64 tp_name; + __u32 name_len; + } tp; /* tracepoint */ + struct { + __u64 config; + __u32 type; + } event; /* generic perf event */ + } perf_event; }; } __attribute__((aligned(8))); diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 80c9ec0..e349bdb 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -3303,9 +3303,107 @@ static void bpf_perf_link_dealloc(struct bpf_link *link) kfree(perf_link); } +static int bpf_perf_link_fill_name(const struct perf_event *event, + char __user *uname, u32 ulen, + u64 *probe_offset, u64 *probe_addr, + u32 *fd_type) +{ + const char *buf; + u32 prog_id; + size_t len; + int err; + + if (!ulen ^ !uname) + return -EINVAL; + if (!uname) + return 0; + + err = bpf_get_perf_event_info(event, &prog_id, fd_type, &buf, + probe_offset, probe_addr); + if (err) + return err; + + len = strlen(buf); + if (buf) { + err = bpf_copy_to_user(uname, buf, ulen, len); + if (err) + return err; + } else { + char zero = '\0'; + + if (put_user(zero, uname)) + return -EFAULT; + } + return 0; +} + +static int bpf_perf_link_fill_probe(const struct perf_event *event, + struct bpf_link_info *info) +{ + char __user *uname = u64_to_user_ptr(info->perf_event.probe.name); + u32 ulen = info->perf_event.probe.name_len; + u64 addr, off; + u32 type; + int err; + + err = bpf_perf_link_fill_name(event, uname, ulen, &off, &addr, &type); + if (err) + return err; + info->perf_event.probe.offset = off; + if (type == BPF_FD_TYPE_KRETPROBE || type == BPF_FD_TYPE_URETPROBE) + info->perf_event.probe.retprobe = 1; + else + info->perf_event.probe.retprobe = 0; + + if (kptr_restrict == 2) + return 0; + info->perf_event.probe.addr = addr; + return 0; +} + +static int bpf_perf_link_fill_tp(const struct perf_event *event, + struct bpf_link_info *info) +{ + char __user *uname = u64_to_user_ptr(info->perf_event.tp.tp_name); + u32 ulen = info->perf_event.tp.name_len; + u64 addr, off; + u32 type; + + return bpf_perf_link_fill_name(event, uname, ulen, &off, &addr, &type); +} + +static int bpf_perf_link_fill_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; + 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; + if (event->prog->type == BPF_PROG_TYPE_PERF_EVENT) + return bpf_perf_link_fill_event(event, info); + if (event->prog->type == BPF_PROG_TYPE_TRACEPOINT) + return bpf_perf_link_fill_tp(event, info); + return bpf_perf_link_fill_probe(event, info); +} + 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 d99cc16..c3b821d 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -6443,6 +6443,28 @@ struct bpf_link_info { __u32 count; __u8 retprobe; } kprobe_multi; + union { + struct { + /* The name is: + * a) uprobe: file name + * b) kprobe: kernel function + */ + __aligned_u64 name; /* in/out: name buffer ptr */ + __u32 name_len; + __u32 offset; /* offset from the name */ + __u64 addr; + __u8 retprobe; + } probe; /* uprobe, kprobe */ + struct { + /* in/out: tracepoint name buffer ptr */ + __aligned_u64 tp_name; + __u32 name_len; + } tp; /* tracepoint */ + struct { + __u64 config; + __u32 type; + } event; /* generic perf event */ + } perf_event; }; } __attribute__((aligned(8)));