[PATCH 02/22] perf tools: Enable passing bpf object file to --event

[Wang Nan]

By introducing new rules in tools/perf/util/parse-events.[ly], this
patch enables 'perf record --event bpf_file.o' to select events by an
eBPF object file. It calls parse_events_load_bpf() to load that file,
which uses bpf__prepare_load() and finally calls bpf_object__open() for
the object files.

After applying this patch, commands like:

 # perf record --event foo.o sleep

become possible.

However, until now this patch is unable to link any useful staff onto
the list because the creating of probe points and BPF program attaching
have not been implemented. Adding this patch before them so following
patches can build them step by step in a testable way.

Before real events are possible to be extracted, to avoid perf report
error because of empty evsel list, this patch link a dummy evsel. The dummy
event related code will be removed when probing and extracting code is
ready.

Signed-off-by: Wang Nan <wangnan0@xxxxxxxxxx>
Cc: Alexei Starovoitov <ast@xxxxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
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: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Zefan Li <lizefan@xxxxxxxxxx>
Cc: pi3orama@xxxxxxx
Link: http://lkml.kernel.org/n/ebpf-6yw9eg0ej3l4jnqhinngkw86@xxxxxxxxxxxxxx
---
 tools/perf/perf.c              |  2 ++
 tools/perf/util/Build          |  1 +
 tools/perf/util/parse-events.c | 56 ++++++++++++++++++++++++++++++++++++++++++
 tools/perf/util/parse-events.h |  8 ++++++
 tools/perf/util/parse-events.l |  3 +++
 tools/perf/util/parse-events.y | 18 +++++++++++++-
 6 files changed, 87 insertions(+), 1 deletion(-)

diff --git a/tools/perf/perf.c b/tools/perf/perf.c
index 1fded92..7a0949e 100644
--- a/tools/perf/perf.c
+++ b/tools/perf/perf.c
@@ -15,6 +15,7 @@
 #include "util/run-command.h"
 #include "util/parse-events.h"
 #include "util/parse-options.h"
+#include "util/bpf-loader.h"
 #include "util/debug.h"
 #include <api/fs/tracing_path.h>
 #include <pthread.h>
@@ -371,6 +372,7 @@ static int run_builtin(struct cmd_struct *p, int argc, const char **argv)
 	status = p->fn(argc, argv, prefix);
 	exit_browser(status);
 	perf_env__exit(&perf_env);
+	bpf__clear();
 
 	if (status)
 		return status & 0xff;
diff --git a/tools/perf/util/Build b/tools/perf/util/Build
index 4bc7a9a..b808151 100644
--- a/tools/perf/util/Build
+++ b/tools/perf/util/Build
@@ -86,6 +86,7 @@ libperf-$(CONFIG_AUXTRACE) += intel-bts.o
 libperf-y += parse-branch-options.o
 libperf-y += parse-regs-options.o
 
+libperf-$(CONFIG_LIBBPF) += bpf-loader.o
 libperf-$(CONFIG_LIBELF) += symbol-elf.o
 libperf-$(CONFIG_LIBELF) += probe-file.o
 libperf-$(CONFIG_LIBELF) += probe-event.o
diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index 61c2bc2..0d4afba 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -11,6 +11,7 @@
 #include "symbol.h"
 #include "cache.h"
 #include "header.h"
+#include "bpf-loader.h"
 #include "debug.h"
 #include <api/fs/tracing_path.h>
 #include "parse-events-bison.h"
@@ -515,6 +516,61 @@ int parse_events_add_tracepoint(struct list_head *list, int *idx,
 		return add_tracepoint_event(list, idx, sys, event, error);
 }
 
+int parse_events_load_bpf_obj(struct parse_events_evlist *data,
+			      struct list_head *list,
+			      struct bpf_object *obj)
+{
+	int err;
+	char errbuf[BUFSIZ];
+
+	if (IS_ERR(obj) || !obj) {
+		snprintf(errbuf, sizeof(errbuf),
+			 "Internal error: load bpf obj with NULL");
+		err = -EINVAL;
+		goto errout;
+	}
+
+	/*
+	 * Temporary add a dummy event here so we can check whether
+	 * basic bpf loader works. Will be removed in following patch.
+	 */
+	return parse_events_add_numeric(data, list, PERF_TYPE_SOFTWARE,
+					PERF_COUNT_SW_DUMMY, NULL);
+errout:
+	data->error->help = strdup("(add -v to see detail)");
+	data->error->str = strdup(errbuf);
+	return err;
+}
+
+int parse_events_load_bpf(struct parse_events_evlist *data,
+			  struct list_head *list,
+			  char *bpf_file_name)
+{
+	struct bpf_object *obj;
+
+	obj = bpf__prepare_load(bpf_file_name);
+	if (IS_ERR(obj) || !obj) {
+		char errbuf[BUFSIZ];
+		int err;
+
+		err = obj ? PTR_ERR(obj) : -EINVAL;
+
+		if (err == -ENOTSUP)
+			snprintf(errbuf, sizeof(errbuf),
+				 "BPF support is not compiled");
+		else
+			snprintf(errbuf, sizeof(errbuf),
+				 "BPF object file '%s' is invalid",
+				 bpf_file_name);
+
+		data->error->help = strdup("(add -v to see detail)");
+		data->error->str = strdup(errbuf);
+		return err;
+	}
+
+	return parse_events_load_bpf_obj(data, list, obj);
+}
+
 static int
 parse_breakpoint_type(const char *type, struct perf_event_attr *attr)
 {
diff --git a/tools/perf/util/parse-events.h b/tools/perf/util/parse-events.h
index ffee7ec..304f587 100644
--- a/tools/perf/util/parse-events.h
+++ b/tools/perf/util/parse-events.h
@@ -120,6 +120,14 @@ int parse_events_name(struct list_head *list, char *name);
 int parse_events_add_tracepoint(struct list_head *list, int *idx,
 				char *sys, char *event,
 				struct parse_events_error *error);
+int parse_events_load_bpf(struct parse_events_evlist *data,
+			  struct list_head *list,
+			  char *bpf_file_name);
+/* Provide this function for perf test */
+struct bpf_object;
+int parse_events_load_bpf_obj(struct parse_events_evlist *data,
+			      struct list_head *list,
+			      struct bpf_object *obj);
 int parse_events_add_numeric(struct parse_events_evlist *data,
 			     struct list_head *list,
 			     u32 type, u64 config,
diff --git a/tools/perf/util/parse-events.l b/tools/perf/util/parse-events.l
index 936d566..22e8f93 100644
--- a/tools/perf/util/parse-events.l
+++ b/tools/perf/util/parse-events.l
@@ -115,6 +115,7 @@ do {							\
 group		[^,{}/]*[{][^}]*[}][^,{}/]*
 event_pmu	[^,{}/]+[/][^/]*[/][^,{}/]*
 event		[^,{}/]+
+bpf_object	.*\.(o|bpf)
 
 num_dec		[0-9]+
 num_hex		0x[a-fA-F0-9]+
@@ -159,6 +160,7 @@ modifier_bp	[rwx]{1,3}
 		}
 
 {event_pmu}	|
+{bpf_object}	|
 {event}		{
 			BEGIN(INITIAL);
 			REWIND(1);
@@ -264,6 +266,7 @@ r{num_raw_hex}		{ return raw(yyscanner); }
 {num_hex}		{ return value(yyscanner, 16); }
 
 {modifier_event}	{ return str(yyscanner, PE_MODIFIER_EVENT); }
+{bpf_object}		{ return str(yyscanner, PE_BPF_OBJECT); }
 {name}			{ return pmu_str_check(yyscanner); }
 "/"			{ BEGIN(config); return '/'; }
 -			{ return '-'; }
diff --git a/tools/perf/util/parse-events.y b/tools/perf/util/parse-events.y
index 8bcc458..3bc79b2 100644
--- a/tools/perf/util/parse-events.y
+++ b/tools/perf/util/parse-events.y
@@ -42,6 +42,7 @@ static inc_group_count(struct list_head *list,
 %token PE_VALUE PE_VALUE_SYM_HW PE_VALUE_SYM_SW PE_RAW PE_TERM
 %token PE_EVENT_NAME
 %token PE_NAME
+%token PE_BPF_OBJECT
 %token PE_MODIFIER_EVENT PE_MODIFIER_BP
 %token PE_NAME_CACHE_TYPE PE_NAME_CACHE_OP_RESULT
 %token PE_PREFIX_MEM PE_PREFIX_RAW PE_PREFIX_GROUP
@@ -53,6 +54,7 @@ static inc_group_count(struct list_head *list,
 %type <num> PE_RAW
 %type <num> PE_TERM
 %type <str> PE_NAME
+%type <str> PE_BPF_OBJECT
 %type <str> PE_NAME_CACHE_TYPE
 %type <str> PE_NAME_CACHE_OP_RESULT
 %type <str> PE_MODIFIER_EVENT
@@ -69,6 +71,7 @@ static inc_group_count(struct list_head *list,
 %type <head> event_legacy_tracepoint
 %type <head> event_legacy_numeric
 %type <head> event_legacy_raw
+%type <head> event_bpf_file
 %type <head> event_def
 %type <head> event_mod
 %type <head> event_name
@@ -198,7 +201,8 @@ event_def: event_pmu |
 	   event_legacy_mem |
 	   event_legacy_tracepoint sep_dc |
 	   event_legacy_numeric sep_dc |
-	   event_legacy_raw sep_dc
+	   event_legacy_raw sep_dc |
+	   event_bpf_file
 
 event_pmu:
 PE_NAME '/' event_config '/'
@@ -422,6 +426,18 @@ PE_RAW
 	$$ = list;
 }
 
+event_bpf_file:
+PE_BPF_OBJECT
+{
+	struct parse_events_evlist *data = _data;
+	struct parse_events_error *error = data->error;
+	struct list_head *list;
+
+	ALLOC_LIST(list);
+	ABORT_ON(parse_events_load_bpf(data, list, $1));
+	$$ = list;
+}
+
 start_terms: event_config
 {
 	struct parse_events_terms *data = _data;
-- 
1.8.3.4

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/