[PATCH 07/27] perf record: Load all eBPF object into kernel

[Wang Nan]

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

Signed-off-by: Wang Nan <wangnan0@xxxxxxxxxx>
Cc: Alexei Starovoitov <ast@xxxxxxxxxxxx>
Cc: Brendan Gregg <brendan.d.gregg@xxxxxxxxx>
Cc: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: He Kuang <hekuang@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Kaixu Xia <xiakaixu@xxxxxxxxxx>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Zefan Li <lizefan@xxxxxxxxxx>
Cc: pi3orama@xxxxxxx
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Link: http://lkml.kernel.org/n/1436445342-1402-24-git-send-email-wangnan0@xxxxxxxxxx
---
 tools/perf/builtin-record.c  | 15 +++++++++++++++
 tools/perf/util/bpf-loader.c | 28 ++++++++++++++++++++++++++++
 tools/perf/util/bpf-loader.h | 10 ++++++++++
 3 files changed, 53 insertions(+)

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index aebf086..a64f0c9 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -1145,6 +1145,21 @@ int cmd_record(int argc, const char **argv, const char *prefix __maybe_unused)
 		goto out_symbol_exit;
 	}
 
+	/*
+	 * bpf__probe() also calls symbol__init() if there are probe
+	 * events in bpf objects, so calling symbol_exit when failure
+	 * is safe. If there is no probe event, bpf__load() always
+	 * success.
+	 */
+	err = bpf__load();
+	if (err) {
+		pr_err("Loading BPF programs failed:\n");
+
+		bpf__strerror_load(err, errbuf, sizeof(errbuf));
+		pr_err("\t%s\n", errbuf);
+		goto out_symbol_exit;
+	}
+
 	symbol__init(NULL);
 
 	if (symbol_conf.kptr_restrict)
diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c
index b44a874..8ac8b23 100644
--- a/tools/perf/util/bpf-loader.c
+++ b/tools/perf/util/bpf-loader.c
@@ -267,6 +267,25 @@ out:
 	return err < 0 ? err : 0;
 }
 
+int bpf__load(void)
+{
+	struct bpf_object *obj, *tmp;
+	int err = 0;
+
+	bpf_object__for_each_safe(obj, tmp) {
+		err = bpf_object__load(obj);
+		if (err) {
+			pr_debug("bpf: load objects failed\n");
+			goto errout;
+		}
+	}
+	return 0;
+errout:
+	bpf_object__for_each_safe(obj, tmp)
+		bpf_object__unload(obj);
+	return err;
+}
+
 #define bpf__strerror_head(err, buf, size) \
 	char sbuf[STRERR_BUFSIZE], *emsg;\
 	if (err < 0)\
@@ -306,3 +325,12 @@ int bpf__strerror_probe(int err, char *buf, size_t size)
 	bpf__strerror_end();
 	return 0;
 }
+
+int bpf__strerror_load(int err, char *buf, size_t size)
+{
+	bpf__strerror_head(err, buf, size);
+	bpf__strerror_entry(EINVAL, "%s: add -v to see detail. Run a CONFIG_BPF_SYSCALL kernel?",
+			    emsg)
+	bpf__strerror_end();
+	return 0;
+}
diff --git a/tools/perf/util/bpf-loader.h b/tools/perf/util/bpf-loader.h
index 3f5ddfa..01805d6 100644
--- a/tools/perf/util/bpf-loader.h
+++ b/tools/perf/util/bpf-loader.h
@@ -19,6 +19,9 @@ int bpf__probe(void);
 int bpf__unprobe(void);
 int bpf__strerror_probe(int err, char *buf, size_t size);
 
+int bpf__load(void);
+int bpf__strerror_load(int err, char *buf, size_t size);
+
 void bpf__clear(void);
 #else
 static inline int bpf__prepare_load(const char *filename __maybe_unused)
@@ -29,6 +32,7 @@ static inline int bpf__prepare_load(const char *filename __maybe_unused)
 
 static inline int bpf__probe(void) { return 0; }
 static inline int bpf__unprobe(void) { return 0; }
+static inline int bpf__load(void) { return 0; }
 static inline void bpf__clear(void) { }
 
 static inline int
@@ -53,5 +57,11 @@ static inline int bpf__strerror_probe(int err __maybe_unused,
 {
 	return __bpf_strerror(buf, size);
 }
+
+static inline int bpf__strerror_load(int err __maybe_unused,
+				     char *buf, size_t size)
+{
+	return __bpf_strerror(buf, size);
+}
 #endif
 #endif
-- 
1.8.3.4

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