[PATCH 04/22] perf record: Load eBPF object into kernel

[Wang Nan <wangnan0@huawei.com>]

This patch utilizes bpf_object__load() provided by libbpf to load all
objects into kernel.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: David Ahern <dsahern@gmail.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kaixu Xia <xiakaixu@huawei.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Link: http://lkml.kernel.org/n/ebpf-6yw9eg0ej3l4jnqhinngkw86@git.kernel.org
---
 tools/perf/util/bpf-loader.c   | 22 ++++++++++++++++++++++
 tools/perf/util/bpf-loader.h   | 11 +++++++++++
 tools/perf/util/parse-events.c |  6 ++++++
 3 files changed, 39 insertions(+)

diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c
index 1a10b6c..39732a4 100644
--- a/tools/perf/util/bpf-loader.c
+++ b/tools/perf/util/bpf-loader.c
@@ -242,6 +242,18 @@ int bpf__unprobe(struct bpf_object *obj)
 	return ret;
 }
 
+int bpf__load(struct bpf_object *obj)
+{
+	int err;
+
+	err = bpf_object__load(obj);
+	if (err) {
+		pr_debug("bpf: load objects failed\n");
+		return err;
+	}
+	return 0;
+}
+
 #define bpf__strerror_head(err, buf, size) \
 	char sbuf[STRERR_BUFSIZE], *emsg;\
 	if (!size)\
@@ -274,3 +286,13 @@ int bpf__strerror_probe(struct bpf_object *obj __maybe_unused,
 	bpf__strerror_end(buf, size);
 	return 0;
 }
+
+int bpf__strerror_load(struct bpf_object *obj __maybe_unused,
+		       int err, char *buf, size_t size)
+{
+	bpf__strerror_head(err, buf, size);
+	bpf__strerror_entry(EINVAL, "%s: Are you root and runing a CONFIG_BPF_SYSCALL kernel?",
+			    emsg)
+	bpf__strerror_end(buf, size);
+	return 0;
+}
diff --git a/tools/perf/util/bpf-loader.h b/tools/perf/util/bpf-loader.h
index b819622..b091ceb 100644
--- a/tools/perf/util/bpf-loader.h
+++ b/tools/perf/util/bpf-loader.h
@@ -23,6 +23,9 @@ int bpf__unprobe(struct bpf_object *obj);
 int bpf__strerror_probe(struct bpf_object *obj, int err,
 			char *buf, size_t size);
 
+int bpf__load(struct bpf_object *obj);
+int bpf__strerror_load(struct bpf_object *obj, int err,
+		       char *buf, size_t size);
 #else
 static inline struct bpf_object *
 bpf__prepare_load(const char *filename __maybe_unused)
@@ -35,6 +38,7 @@ static inline void bpf__clear(void) { }
 
 static inline int bpf__probe(struct bpf_object *obj __maybe_unused) { return 0;}
 static inline int bpf__unprobe(struct bpf_object *obj __maybe_unused) { return 0;}
+static inline int bpf__load(struct bpf_object *obj __maybe_unused) { return 0; }
 
 static inline int
 __bpf_strerror(char *buf, size_t size)
@@ -55,5 +59,12 @@ bpf__strerror_probe(struct bpf_object *obj __maybe_unused,
 {
 	return __bpf_strerror(buf, size);
 }
+
+static inline int bpf__strerror_load(struct bpf_object *obj __maybe_unused,
+				     int err __maybe_unused,
+				     char *buf, size_t size)
+{
+	return __bpf_strerror(buf, size);
+}
 #endif
 #endif
diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index 354da59..a7152f3 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -542,6 +542,12 @@ int parse_events_load_bpf_obj(struct parse_events_evlist *data,
 		registered_unprobe_atexit = true;
 	}
 
+	err = bpf__load(obj);
+	if (err) {
+		bpf__strerror_load(obj, err, errbuf, sizeof(errbuf));
+		goto errout;
+	}
+
 	/*
 	 * Temporary add a dummy event here so we can check whether
 	 * basic bpf loader works. Will be removed in following patch.
-- 
1.8.3.4