From mboxrd@z Thu Jan 1 00:00:00 1970 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=-3.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_PASS,T_DKIMWL_WL_HIGH,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 C6682C46460 for ; Thu, 9 Aug 2018 15:01:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8189E214FF for ; Thu, 9 Aug 2018 15:01:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="xy7ByFMt" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8189E214FF Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733121AbeHIR0i (ORCPT ); Thu, 9 Aug 2018 13:26:38 -0400 Received: from mail.kernel.org ([198.145.29.99]:38582 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732712AbeHIR0i (ORCPT ); Thu, 9 Aug 2018 13:26:38 -0400 Received: from jouet.infradead.org (179-240-153-38.3g.claro.net.br [179.240.153.38]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id D58CB21D62; Thu, 9 Aug 2018 15:01:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1533826880; bh=7bJuzvCx4cdc3cgLxW6+ZZmE5Cjw9iVEw6d8CjkMe6k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=xy7ByFMtK/R1dmwCifNvB6tjgl9nueV7gL/gDs5Pr7DI55jFvH2DqAn5LwhylJJRS VTjyWlK6CVWQXAy4S46DeBx+bVV88cWHVPZYU4xT/X2G0rmoraYSkDnIAH7yMJt9t3 BRAdhQ4/hQywhRkh1+dm/nM9FHFglIi11Jl4iZ2E= From: Arnaldo Carvalho de Melo To: Ingo Molnar Cc: Clark Williams , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, Arnaldo Carvalho de Melo , Adrian Hunter , David Ahern , Jiri Olsa , Namhyung Kim , Wang Nan Subject: [PATCH 34/44] perf bpf: Add bpf/stdio.h wrapper to bpf_perf_event_output function Date: Thu, 9 Aug 2018 11:58:12 -0300 Message-Id: <20180809145822.21391-35-acme@kernel.org> X-Mailer: git-send-email 2.14.4 In-Reply-To: <20180809145822.21391-1-acme@kernel.org> References: <20180809145822.21391-1-acme@kernel.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Arnaldo Carvalho de Melo That, together with the map __bpf_output__ that is already handled by 'perf trace' to print that event's contents as strings provides a debugging facility, to show it in use, print a simple string everytime the syscalls:sys_enter_openat() syscall tracepoint is hit: # cat tools/perf/examples/bpf/hello.c #include int syscall_enter(openat)(void *args) { puts("Hello, world\n"); return 0; } license(GPL); # # perf trace -e openat,tools/perf/examples/bpf/hello.c cat /etc/passwd > /dev/null 0.016 ( ): __bpf_stdout__:Hello, world 0.018 ( 0.010 ms): cat/9079 openat(dfd: CWD, filename: /etc/ld.so.cache, flags: CLOEXEC) = 3 0.057 ( ): __bpf_stdout__:Hello, world 0.059 ( 0.011 ms): cat/9079 openat(dfd: CWD, filename: /lib64/libc.so.6, flags: CLOEXEC) = 3 0.417 ( ): __bpf_stdout__:Hello, world 0.419 ( 0.009 ms): cat/9079 openat(dfd: CWD, filename: /etc/passwd) = 3 # This is part of an ongoing experimentation on making eBPF scripts as consumed by perf to be as concise as possible and using familiar concepts such as stdio.h functions, that end up just wrapping the existing BPF functions, trying to hide as much boilerplate as possible while using just conventions and C preprocessor tricks. Cc: Adrian Hunter Cc: David Ahern Cc: Jiri Olsa Cc: Namhyung Kim Cc: Wang Nan Link: https://lkml.kernel.org/n/tip-4tiaqlx5crf0fwpe7a6j84x7@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/examples/bpf/hello.c | 9 +++++++++ tools/perf/include/bpf/stdio.h | 19 +++++++++++++++++++ 2 files changed, 28 insertions(+) create mode 100644 tools/perf/examples/bpf/hello.c create mode 100644 tools/perf/include/bpf/stdio.h diff --git a/tools/perf/examples/bpf/hello.c b/tools/perf/examples/bpf/hello.c new file mode 100644 index 000000000000..cf3c2fdc7f79 --- /dev/null +++ b/tools/perf/examples/bpf/hello.c @@ -0,0 +1,9 @@ +#include + +int syscall_enter(openat)(void *args) +{ + puts("Hello, world\n"); + return 0; +} + +license(GPL); diff --git a/tools/perf/include/bpf/stdio.h b/tools/perf/include/bpf/stdio.h new file mode 100644 index 000000000000..2899cb7bfed8 --- /dev/null +++ b/tools/perf/include/bpf/stdio.h @@ -0,0 +1,19 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include + +struct bpf_map SEC("maps") __bpf_stdout__ = { + .type = BPF_MAP_TYPE_PERF_EVENT_ARRAY, + .key_size = sizeof(int), + .value_size = sizeof(u32), + .max_entries = __NR_CPUS__, +}; + +static int (*perf_event_output)(void *, struct bpf_map *, int, void *, unsigned long) = + (void *)BPF_FUNC_perf_event_output; + +#define puts(from) \ + ({ const int __len = sizeof(from); \ + char __from[__len] = from; \ + perf_event_output(args, &__bpf_stdout__, BPF_F_CURRENT_CPU, \ + &__from, __len & (sizeof(from) - 1)); }) -- 2.14.4