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[209.132.180.67]) by mx.google.com with ESMTP id ya7si2879962pab.157.2015.09.06.00.16.12; Sun, 06 Sep 2015 00:16:13 -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 S1752496AbbIFHQC (ORCPT + 28 others); Sun, 6 Sep 2015 03:16:02 -0400 Received: from szxga01-in.huawei.com ([58.251.152.64]:7377 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751155AbbIFHOl (ORCPT ); Sun, 6 Sep 2015 03:14:41 -0400 Received: from 172.24.1.48 (EHLO SZXEML423-HUB.china.huawei.com) ([172.24.1.48]) by szxrg01-dlp.huawei.com (MOS 4.3.7-GA FastPath queued) with ESMTP id CUK94017; Sun, 06 Sep 2015 15:14:05 +0800 (CST) Received: from linux-4hy3.site (10.107.193.248) by SZXEML423-HUB.china.huawei.com (10.82.67.154) with Microsoft SMTP Server id 14.3.235.1; Sun, 6 Sep 2015 15:13:58 +0800 From: Wang Nan To: , , , CC: , , , , , , , , , , , Subject: [PATCH 05/27] perf record, bpf: Parse and create probe points for BPF programs Date: Sun, 6 Sep 2015 07:13:21 +0000 Message-ID: <1441523623-152703-6-git-send-email-wangnan0@huawei.com> X-Mailer: git-send-email 1.8.3.4 In-Reply-To: <1441523623-152703-1-git-send-email-wangnan0@huawei.com> References: <1441523623-152703-1-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 209.85.215.46 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 introduces bpf__{un,}probe() functions to enable callers to create kprobe points based on section names of BPF programs. It parses the section names of each eBPF program and creates corresponding 'struct perf_probe_event' structures. The parse_perf_probe_command() function is used to do the main parsing work. Parsing result is stored into an array to satisify {convert,apply}_perf_probe_events(). It accepts an array of 'struct perf_probe_event' and do all the work in one call. Define PERF_BPF_PROBE_GROUP as "perf_bpf_probe", which will be used as the group name of all eBPF probing points. probe_conf.max_probes is set to MAX_PROBES to support glob matching. Before ending of bpf__probe(), data in each 'struct perf_probe_event' is cleaned. Things will be changed by following patches because they need 'struct probe_trace_event' in them, 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 Link: http://lkml.kernel.org/n/1436445342-1402-21-git-send-email-wangnan0@huawei.com Link: http://lkml.kernel.org/n/1436445342-1402-23-git-send-email-wangnan0@huawei.com [Merged by two patches wangnan: Utilize new perf probe API {convert,apply,cleanup}_perf_probe_events() ] Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/builtin-record.c | 19 +++++- tools/perf/util/bpf-loader.c | 149 +++++++++++++++++++++++++++++++++++++++++++ tools/perf/util/bpf-loader.h | 13 ++++ 3 files changed, 180 insertions(+), 1 deletion(-) diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c index f886706..b56109f 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c @@ -1141,7 +1141,23 @@ int cmd_record(int argc, const char **argv, const char *prefix __maybe_unused) if (err) goto out_bpf_clear; - err = -ENOMEM; + /* + * bpf__probe must be called before symbol__init() because we + * need init_symbol_maps. If called after symbol__init, + * symbol_conf.sort_by_name won't take effect. + * + * bpf__unprobe() is safe even if bpf__probe() failed, and it + * also calls symbol__init. Therefore, goto out_symbol_exit + * is safe when probe failed. + */ + err = bpf__probe(); + if (err) { + bpf__strerror_probe(err, errbuf, sizeof(errbuf)); + + pr_err("Probing at events in BPF object failed.\n"); + pr_err("\t%s\n", errbuf); + goto out_symbol_exit; + } symbol__init(NULL); @@ -1202,6 +1218,7 @@ out_symbol_exit: perf_evlist__delete(rec->evlist); symbol__exit(); auxtrace_record__free(rec->itr); + bpf__unprobe(); out_bpf_clear: bpf__clear(); return err; diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c index 88531ea..10505cb 100644 --- a/tools/perf/util/bpf-loader.c +++ b/tools/perf/util/bpf-loader.c @@ -9,6 +9,8 @@ #include "perf.h" #include "debug.h" #include "bpf-loader.h" +#include "probe-event.h" +#include "probe-finder.h" #define DEFINE_PRINT_FN(name, level) \ static int libbpf_##name(const char *fmt, ...) \ @@ -28,6 +30,58 @@ DEFINE_PRINT_FN(debug, 1) static bool libbpf_initialized; +static int +config_bpf_program(struct bpf_program *prog, struct perf_probe_event *pev) +{ + const char *config_str; + int err; + + config_str = bpf_program__title(prog, false); + if (!config_str) { + pr_debug("bpf: unable to get title for program\n"); + return -EINVAL; + } + + pr_debug("bpf: config program '%s'\n", config_str); + err = parse_perf_probe_command(config_str, pev); + if (err < 0) { + pr_debug("bpf: '%s' is not a valid config string\n", + config_str); + /* parse failed, don't need clear pev. */ + return -EINVAL; + } + + if (pev->group && strcmp(pev->group, PERF_BPF_PROBE_GROUP)) { + pr_debug("bpf: '%s': group for event is set and not '%s'.\n", + config_str, PERF_BPF_PROBE_GROUP); + err = -EINVAL; + goto errout; + } else if (!pev->group) + pev->group = strdup(PERF_BPF_PROBE_GROUP); + + if (!pev->group) { + pr_debug("bpf: strdup failed\n"); + err = -ENOMEM; + goto errout; + } + + if (!pev->event) { + pr_debug("bpf: '%s': event name is missing\n", + config_str); + err = -EINVAL; + goto errout; + } + + pr_debug("bpf: config '%s' is ok\n", config_str); + + return 0; + +errout: + if (pev) + clear_perf_probe_event(pev); + return err; +} + int bpf__prepare_load(const char *filename) { struct bpf_object *obj; @@ -59,6 +113,90 @@ void bpf__clear(void) bpf_object__close(obj); } +static bool is_probed; + +int bpf__unprobe(void) +{ + struct strfilter *delfilter; + int ret; + + if (!is_probed) + return 0; + + delfilter = strfilter__new(PERF_BPF_PROBE_GROUP ":*", NULL); + if (!delfilter) { + pr_debug("Failed to create delfilter when unprobing\n"); + return -ENOMEM; + } + + ret = del_perf_probe_events(delfilter); + strfilter__delete(delfilter); + if (ret < 0 && is_probed) + pr_debug("Error: failed to delete events: %s\n", + strerror(-ret)); + else + is_probed = false; + return ret < 0 ? ret : 0; +} + +int bpf__probe(void) +{ + int err, nr_events = 0; + struct bpf_object *obj, *tmp; + struct bpf_program *prog; + struct perf_probe_event *pevs; + + pevs = calloc(MAX_PROBES, sizeof(pevs[0])); + if (!pevs) + return -ENOMEM; + + bpf_object__for_each_safe(obj, tmp) { + bpf_object__for_each_program(prog, obj) { + err = config_bpf_program(prog, &pevs[nr_events++]); + if (err < 0) + goto out; + + if (nr_events >= MAX_PROBES) { + pr_debug("Too many (more than %d) events\n", + MAX_PROBES); + err = -ERANGE; + goto out; + }; + } + } + + if (!nr_events) { + /* + * Don't call following code to prevent perf report failure + * init_symbol_maps can fail when perf is started by non-root + * user, which prevent non-root user track normal events even + * without using BPF, because bpf__probe() is called by + * 'perf record' unconditionally. + */ + err = 0; + goto out; + } + + probe_conf.max_probes = MAX_PROBES; + /* Let convert_perf_probe_events generates probe_trace_event (tevs) */ + err = convert_perf_probe_events(pevs, nr_events); + if (err < 0) { + pr_debug("bpf_probe: failed to convert perf probe events"); + goto out; + } + + err = apply_perf_probe_events(pevs, nr_events); + if (err < 0) + pr_debug("bpf probe: failed to probe events\n"); + else + is_probed = true; +out_cleanup: + cleanup_perf_probe_events(pevs, nr_events); +out: + free(pevs); + return err < 0 ? err : 0; +} + #define bpf__strerror_head(err, buf, size) \ char sbuf[STRERR_BUFSIZE], *emsg;\ if (!size)\ @@ -90,3 +228,14 @@ int bpf__strerror_prepare_load(const char *filename, int err, bpf__strerror_end(buf, size); return 0; } + +int bpf__strerror_probe(int err, char *buf, size_t size) +{ + bpf__strerror_head(err, buf, size); + bpf__strerror_entry(ERANGE, "Too many (more than %d) events", + MAX_PROBES); + bpf__strerror_entry(ENOENT, "Selected kprobe point doesn't exist."); + bpf__strerror_entry(EEXIST, "Selected kprobe point already exist, try perf probe -d '*'."); + bpf__strerror_end(buf, size); + return 0; +} diff --git a/tools/perf/util/bpf-loader.h b/tools/perf/util/bpf-loader.h index 12be630..6b09a85 100644 --- a/tools/perf/util/bpf-loader.h +++ b/tools/perf/util/bpf-loader.h @@ -9,10 +9,15 @@ #include #include "debug.h" +#define PERF_BPF_PROBE_GROUP "perf_bpf_probe" + #ifdef HAVE_LIBBPF_SUPPORT int bpf__prepare_load(const char *filename); int bpf__strerror_prepare_load(const char *filename, int err, char *buf, size_t size); +int bpf__probe(void); +int bpf__unprobe(void); +int bpf__strerror_probe(int err, char *buf, size_t size); void bpf__clear(void); #else @@ -22,6 +27,8 @@ static inline int bpf__prepare_load(const char *filename __maybe_unused) return -1; } +static inline int bpf__probe(void) { return 0; } +static inline int bpf__unprobe(void) { return 0; } static inline void bpf__clear(void) { } static inline int @@ -43,5 +50,11 @@ bpf__strerror_prepare_load(const char *filename __maybe_unused, { return __bpf_strerror(buf, size); } + +static inline int bpf__strerror_probe(int err __maybe_unused, + char *buf, size_t size) +{ + return __bpf_strerror(buf, size); +} #endif #endif