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Message-ID: <1432704004-171454-26-git-send-email-wangnan0@huawei.com>
Date: Wed, 27 May 2015 05:20:00 +0000
From: Wang Nan <wangnan0@...wei.com>
To: <paulus@...ba.org>, <a.p.zijlstra@...llo.nl>, <mingo@...hat.com>,
<acme@...nel.org>, <namhyung@...nel.org>, <jolsa@...nel.org>,
<dsahern@...il.com>, <daniel@...earbox.net>,
<brendan.d.gregg@...il.com>, <masami.hiramatsu.pt@...achi.com>
CC: <lizefan@...wei.com>, <linux-kernel@...r.kernel.org>,
<pi3orama@....com>
Subject: [RFC PATCH v4 25/29] perf tools: Parse probe points of eBPF programs during preparation
This patch parses section name of each program, and creates
corresponding 'struct perf_probe_event' structure.
parse_perf_probe_command() is used to do the main parsing works.
Parsing result is stored into a global array. This is because
add_perf_probe_events() is non-reentrantable. In following patch,
add_perf_probe_events will be introduced to insert kprobes. It accepts
an array of 'struct perf_probe_event' and do all works in one call.
Define PERF_BPF_PROBE_GROUP as "perf_bpf_probe", which will be used
as group name of all eBPF probing points.
This patch utilizes bpf_program__set_private(), bind perf_probe_event
with bpf program by private field.
Signed-off-by: Wang Nan <wangnan0@...wei.com>
---
tools/perf/util/bpf-loader.c | 123 ++++++++++++++++++++++++++++++++++++++++++-
tools/perf/util/bpf-loader.h | 2 +
2 files changed, 124 insertions(+), 1 deletion(-)
diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c
index eef15f3..1022729 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, ...) \
@@ -28,9 +30,120 @@ DEFINE_PRINT_FN(debug, 1)
static bool libbpf_initialized = false;
+static struct perf_probe_event probe_event_array[MAX_PROBES];
+static size_t nr_probe_events;
+
+static struct perf_probe_event *
+alloc_perf_probe_event(void)
+{
+ struct perf_probe_event *pev;
+ int n = nr_probe_events;
+ if (n >= MAX_PROBES) {
+ pr_err("bpf: too many events, increase MAX_PROBES\n");
+ return NULL;
+ }
+
+ nr_probe_events = n + 1;
+ pev = &probe_event_array[n];
+ bzero(pev, sizeof(*pev));
+ return pev;
+}
+
+struct bpf_prog_priv {
+ struct perf_probe_event *pev;
+};
+
+static void
+bpf_prog_priv__clear(struct bpf_program *prog __maybe_unused,
+ void *_priv)
+{
+ struct bpf_prog_priv *priv = _priv;
+ if (priv->pev)
+ clear_perf_probe_event(priv->pev);
+ free(priv);
+}
+
+static int
+config_bpf_program(struct bpf_program *prog)
+{
+ struct perf_probe_event *pev = alloc_perf_probe_event();
+ struct bpf_prog_priv *priv = NULL;
+ const char *config_str;
+ int err;
+
+ /* pr_err has been done by alloc_perf_probe_event */
+ if (!pev)
+ return -ENOMEM;
+
+ err = bpf_program__get_title(prog, &config_str, false);
+ if (err || !config_str) {
+ pr_err("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_err("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_err("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_err("bpf: strdup failed\n");
+ err = -ENOMEM;
+ goto errout;
+ }
+
+ if (!pev->event) {
+ pr_err("bpf: '%s': event name is missing\n",
+ config_str);
+ err = -EINVAL;
+ goto errout;
+ }
+
+ pr_debug("bpf: config '%s' is ok\n", config_str);
+
+ priv = calloc(1, sizeof(*priv));
+ if (!priv) {
+ pr_err("bpf: failed to alloc memory\n");
+ err = -ENOMEM;
+ goto errout;
+ }
+
+ priv->pev = pev;
+
+ err = bpf_program__set_private(prog, priv,
+ bpf_prog_priv__clear);
+ if (err) {
+ pr_err("bpf: set program private failed\n");
+ err = -ENOMEM;
+ goto errout;
+ }
+ return 0;
+
+errout:
+ if (pev)
+ clear_perf_probe_event(pev);
+ if (priv)
+ free(priv);
+ return err;
+}
+
int bpf__prepare_load(const char *filename)
{
struct bpf_object *obj;
+ struct bpf_program *prog;
+ int err = 0;
if (!libbpf_initialized)
libbpf_set_print(libbpf_warning,
@@ -43,12 +156,20 @@ int bpf__prepare_load(const char *filename)
return -EINVAL;
}
+ bpf_object__for_each_program(prog, obj) {
+ err = config_bpf_program(prog);
+ if (err)
+ goto errout;
+ }
+
/*
* Throw object pointer away: it will be retrived using
* bpf_objects iterater.
*/
-
return 0;
+errout:
+ bpf_object__close(obj);
+ return err;
}
void bpf__clear(void)
diff --git a/tools/perf/util/bpf-loader.h b/tools/perf/util/bpf-loader.h
index d5c22da..43d7b99 100644
--- a/tools/perf/util/bpf-loader.h
+++ b/tools/perf/util/bpf-loader.h
@@ -5,6 +5,8 @@
#ifndef __BPF_LOADER_H
#define __BPF_LOADER_H
+#define PERF_BPF_PROBE_GROUP "perf_bpf_probe"
+
int bpf__prepare_load(const char *filename);
void bpf__clear(void);
--
1.8.3.4
--
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