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[209.132.180.67]) by mx.google.com with ESMTP id jv9si13300651pbb.201.2015.08.28.21.25.51; Fri, 28 Aug 2015 21:25:53 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753034AbbH2EZu (ORCPT + 28 others); Sat, 29 Aug 2015 00:25:50 -0400 Received: from szxga02-in.huawei.com ([119.145.14.65]:6395 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752693AbbH2EYL (ORCPT ); Sat, 29 Aug 2015 00:24:11 -0400 Received: from 172.24.1.51 (EHLO szxeml431-hub.china.huawei.com) ([172.24.1.51]) by szxrg02-dlp.huawei.com (MOS 4.3.7-GA FastPath queued) with ESMTP id CRK01388; Sat, 29 Aug 2015 12:23:27 +0800 (CST) Received: from linux-4hy3.site (10.107.193.248) by szxeml431-hub.china.huawei.com (10.82.67.208) with Microsoft SMTP Server id 14.3.235.1; Sat, 29 Aug 2015 12:23:18 +0800 From: Wang Nan To: , , CC: , , , Wang Nan , Brendan Gregg , Daniel Borkmann , David Ahern , "He Kuang" , Jiri Olsa , Kaixu Xia , Masami Hiramatsu , Namhyung Kim , Paul Mackerras , Peter Zijlstra Subject: [PATCH 25/31] perf tools: Generate prologue for BPF programs Date: Sat, 29 Aug 2015 04:21:59 +0000 Message-ID: <1440822125-52691-26-git-send-email-wangnan0@huawei.com> X-Mailer: git-send-email 1.8.3.4 In-Reply-To: <1440822125-52691-1-git-send-email-wangnan0@huawei.com> References: <1440822125-52691-1-git-send-email-wangnan0@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.107.193.248] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: list List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-Removed-Original-Auth: Dkim didn't pass. X-Original-Sender: wangnan0@huawei.com X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of patch+caf_=patchwork-forward=linaro.org@linaro.org designates 209.85.217.174 as permitted sender) smtp.mailfrom=patch+caf_=patchwork-forward=linaro.org@linaro.org Mailing-list: list patchwork-forward@linaro.org; contact patchwork-forward+owners@linaro.org X-Google-Group-Id: 836684582541 List-Post: , List-Help: , List-Archive: List-Unsubscribe: , This patch generates prologue for each 'struct probe_trace_event' for fetching arguments for BPF programs. After bpf__probe(), iterate over each programs to check whether prologue is required. If none of 'struct perf_probe_event' a program will attach to has at least one argument, simply skip preprocessor hooking. For those who prologue is required, calls bpf__gen_prologue() and paste original instruction after prologue. Signed-off-by: Wang Nan Cc: Alexei Starovoitov Cc: Brendan Gregg Cc: Daniel Borkmann Cc: David Ahern Cc: He Kuang Cc: Jiri Olsa Cc: Kaixu Xia Cc: Masami Hiramatsu Cc: Namhyung Kim Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Zefan Li Cc: pi3orama@163.com Cc: Arnaldo Carvalho de Melo Link: http://lkml.kernel.org/n/1436445342-1402-36-git-send-email-wangnan0@huawei.com --- tools/perf/util/bpf-loader.c | 120 ++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 119 insertions(+), 1 deletion(-) diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c index 95e529b..66d9bea 100644 --- a/tools/perf/util/bpf-loader.c +++ b/tools/perf/util/bpf-loader.c @@ -5,10 +5,13 @@ * Copyright (C) 2015 Huawei Inc. */ +#include #include #include "perf.h" #include "debug.h" #include "bpf-loader.h" +#include "bpf-prologue.h" +#include "llvm-utils.h" #include "probe-event.h" #include "probe-finder.h" #include "llvm-utils.h" @@ -42,6 +45,8 @@ struct bpf_prog_priv { struct perf_probe_event *ppev; struct perf_probe_event pev; }; + bool need_prologue; + struct bpf_insn *insns_buf; }; static void @@ -53,6 +58,7 @@ bpf_prog_priv__clear(struct bpf_program *prog __maybe_unused, /* check if pev is initialized */ if (priv && priv->pev_ready) clear_perf_probe_event(&priv->pev); + zfree(&priv->insns_buf); free(priv); } @@ -239,6 +245,103 @@ int bpf__unprobe(void) return ret < 0 ? ret : 0; } +static int +preproc_gen_prologue(struct bpf_program *prog, int n, + struct bpf_insn *orig_insns, int orig_insns_cnt, + struct bpf_prog_prep_result *res) +{ + struct probe_trace_event *tev; + struct perf_probe_event *pev; + struct bpf_prog_priv *priv; + struct bpf_insn *buf; + size_t prologue_cnt = 0; + int err; + + err = bpf_program__get_private(prog, (void **)&priv); + if (err || !priv || !priv->pev_ready) + goto errout; + + pev = &priv->pev; + + if (n < 0 || n >= pev->ntevs) + goto errout; + + tev = &pev->tevs[n]; + + buf = priv->insns_buf; + err = bpf__gen_prologue(tev->args, tev->nargs, + buf, &prologue_cnt, + BPF_MAXINSNS - orig_insns_cnt); + if (err) { + const char *title; + + title = bpf_program__title(prog, false); + if (!title) + title = "??"; + + pr_debug("Failed to generate prologue for program %s\n", + title); + return err; + } + + memcpy(&buf[prologue_cnt], orig_insns, + sizeof(struct bpf_insn) * orig_insns_cnt); + + res->new_insn_ptr = buf; + res->new_insn_cnt = prologue_cnt + orig_insns_cnt; + res->pfd = NULL; + return 0; + +errout: + pr_debug("Internal error in preproc_gen_prologue\n"); + return -EINVAL; +} + +static int hook_load_preprocessor(struct bpf_program *prog) +{ + struct perf_probe_event *pev; + struct bpf_prog_priv *priv; + bool need_prologue = false; + int err, i; + + err = bpf_program__get_private(prog, (void **)&priv); + if (err || !priv) { + pr_debug("Internal error when hook preprocessor\n"); + return -EINVAL; + } + + pev = &priv->pev; + for (i = 0; i < pev->ntevs; i++) { + struct probe_trace_event *tev = &pev->tevs[i]; + + if (tev->nargs > 0) { + need_prologue = true; + break; + } + } + + /* + * Since all tev doesn't have argument, we don't need generate + * prologue. + */ + if (!need_prologue) { + priv->need_prologue = false; + return 0; + } + + priv->need_prologue = true; + priv->insns_buf = malloc(sizeof(struct bpf_insn) * + BPF_MAXINSNS); + if (!priv->insns_buf) { + pr_debug("No enough memory: alloc insns_buf failed\n"); + return -ENOMEM; + } + + err = bpf_program__set_prep(prog, pev->ntevs, + preproc_gen_prologue); + return err; +} + int bpf__probe(void) { int err, nr_events = 0; @@ -289,6 +392,17 @@ int bpf__probe(void) err = sync_bpf_program_pev(prog); if (err) goto out; + /* + * After probing, let's consider prologue, which + * adds program fetcher to BPF programs. + * + * hook_load_preprocessorr() hooks pre-processor + * to bpf_program, let it generate prologue + * dynamically during loading. + */ + err = hook_load_preprocessor(prog); + if (err) + goto out; } } out: @@ -349,7 +463,11 @@ int bpf__foreach_tev(bpf_prog_iter_callback_t func, void *arg) for (i = 0; i < pev->ntevs; i++) { tev = &pev->tevs[i]; - fd = bpf_program__fd(prog); + if (priv->need_prologue) + fd = bpf_program__nth_fd(prog, i); + else + fd = bpf_program__fd(prog); + if (fd < 0) { pr_debug("bpf: failed to get file descriptor\n"); return fd;