[PATCH 06/32] perf tools: Enable passing bpf object file to --event

[Wang Nan <wangnan0@huawei.com>]

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.

Instead of introducing evsel to evlist during parsing, events selected
by eBPF object files are appended separately. The reason is:

 1. During parsing, the probing points have not been initialized.

 2. Currently we are unable to call add_perf_probe_events() twice,
    therefore we have to wait until all such events are collected,
    then probe all points by one call.

The real probing and selecting is reside in following patches.

To collect '--filter' events, add a dummy evsel during parsing.

Since bpf__prepare_load() is possible to be called during cmdline
parsing, all builtin commands which are possible to call
parse_events_option() should release bpf resources during cleanup.
Add bpf__clear() to stat, record, top and trace commands, although
currently we are going to support 'perf record' only.

Commiter note:

Testing if the event parsing changes indeed call the BPF loading
routines:

  [root@felicio ~]# ls -la foo.o
  ls: cannot access foo.o: No such file or directory
  [root@felicio ~]# perf record --event foo.o sleep
  libbpf: failed to open foo.o: No such file or directory
  bpf: failed to load foo.o
  invalid or unsupported event: 'foo.o'
  Run 'perf list' for a list of valid events

   usage: perf record [<options>] [<command>]
      or: perf record [<options>] -- <command> [<options>]

      -e, --event <event>   event selector. use 'perf list' to list available events
  [root@felicio ~]#

Yes, it does this time around.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.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: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/n/1436445342-1402-19-git-send-email-wangnan0@huawei.com
[ The veprintf() and bpf loader parts were split from this one;
  Add bpf__clear() into stat, record, top and trace commands.
  Add dummy evsel when parsing.
]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/builtin-record.c    |  7 +++++--
 tools/perf/builtin-stat.c      |  8 ++++++--
 tools/perf/builtin-top.c       | 10 +++++++---
 tools/perf/builtin-trace.c     |  5 ++++-
 tools/perf/util/Build          |  1 +
 tools/perf/util/parse-events.c | 40 ++++++++++++++++++++++++++++++++++++++++
 tools/perf/util/parse-events.h |  3 +++
 tools/perf/util/parse-events.l |  3 +++
 tools/perf/util/parse-events.y | 18 +++++++++++++++++-
 9 files changed, 86 insertions(+), 9 deletions(-)

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 81829de..31934b1 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -29,6 +29,7 @@
 #include "util/data.h"
 #include "util/auxtrace.h"
 #include "util/parse-branch-options.h"
+#include "util/bpf-loader.h"
 
 #include <unistd.h>
 #include <sched.h>
@@ -1131,13 +1132,13 @@ int cmd_record(int argc, const char **argv, const char *prefix __maybe_unused)
 	if (!rec->itr) {
 		rec->itr = auxtrace_record__init(rec->evlist, &err);
 		if (err)
-			return err;
+			goto out_bpf_clear;
 	}
 
 	err = auxtrace_parse_snapshot_options(rec->itr, &rec->opts,
 					      rec->opts.auxtrace_snapshot_opts);
 	if (err)
-		return err;
+		goto out_bpf_clear;
 
 	err = -ENOMEM;
 
@@ -1200,6 +1201,8 @@ out_symbol_exit:
 	perf_evlist__delete(rec->evlist);
 	symbol__exit();
 	auxtrace_record__free(rec->itr);
+out_bpf_clear:
+	bpf__clear();
 	return err;
 }
 
diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 99b62f1..d50a19a 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -59,6 +59,7 @@
 #include "util/thread.h"
 #include "util/thread_map.h"
 #include "util/counts.h"
+#include "util/bpf-loader.h"
 
 #include <stdlib.h>
 #include <sys/prctl.h>
@@ -1235,7 +1236,8 @@ int cmd_stat(int argc, const char **argv, const char *prefix __maybe_unused)
 		output = fopen(output_name, mode);
 		if (!output) {
 			perror("failed to create output file");
-			return -1;
+			status = -1;
+			goto out;
 		}
 		clock_gettime(CLOCK_REALTIME, &tm);
 		fprintf(output, "# started on %s\n", ctime(&tm.tv_sec));
@@ -1244,7 +1246,8 @@ int cmd_stat(int argc, const char **argv, const char *prefix __maybe_unused)
 		output = fdopen(output_fd, mode);
 		if (!output) {
 			perror("Failed opening logfd");
-			return -errno;
+			status = -errno;
+			goto out;
 		}
 	}
 
@@ -1377,5 +1380,6 @@ int cmd_stat(int argc, const char **argv, const char *prefix __maybe_unused)
 	perf_evlist__free_stats(evsel_list);
 out:
 	perf_evlist__delete(evsel_list);
+	bpf__clear();
 	return status;
 }
diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index 246203b..ee946dc 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -41,6 +41,7 @@
 #include "util/sort.h"
 #include "util/intlist.h"
 #include "util/parse-branch-options.h"
+#include "util/bpf-loader.h"
 #include "arch/common.h"
 
 #include "util/debug.h"
@@ -1271,8 +1272,10 @@ int cmd_top(int argc, const char **argv, const char *prefix __maybe_unused)
 	symbol_conf.priv_size = sizeof(struct annotation);
 
 	symbol_conf.try_vmlinux_path = (symbol_conf.vmlinux_name == NULL);
-	if (symbol__init(NULL) < 0)
-		return -1;
+	if (symbol__init(NULL) < 0) {
+		status = -1;
+		goto out_bpf_clear;
+	}
 
 	sort__setup_elide(stdout);
 
@@ -1290,6 +1293,7 @@ int cmd_top(int argc, const char **argv, const char *prefix __maybe_unused)
 
 out_delete_evlist:
 	perf_evlist__delete(top.evlist);
-
+out_bpf_clear:
+	bpf__clear();
 	return status;
 }
diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index ef5fde6..24c8b63 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -3090,6 +3090,7 @@ int cmd_trace(int argc, const char **argv, const char *prefix __maybe_unused)
 	if (trace.evlist->nr_entries > 0)
 		evlist__set_evsel_handler(trace.evlist, trace__event_handler);
 
+	/* trace__record calls cmd_record, which calls bpf__clear() */
 	if ((argc >= 1) && (strcmp(argv[0], "record") == 0))
 		return trace__record(&trace, argc-1, &argv[1]);
 
@@ -3100,7 +3101,8 @@ int cmd_trace(int argc, const char **argv, const char *prefix __maybe_unused)
 	if (!trace.trace_syscalls && !trace.trace_pgfaults &&
 	    trace.evlist->nr_entries == 0 /* Was --events used? */) {
 		pr_err("Please specify something to trace.\n");
-		return -1;
+		err = -1;
+		goto out;
 	}
 
 	if (output_name != NULL) {
@@ -3159,5 +3161,6 @@ out_close:
 	if (output_name != NULL)
 		fclose(trace.output);
 out:
+	bpf__clear();
 	return err;
 }
diff --git a/tools/perf/util/Build b/tools/perf/util/Build
index e912856..c0ca4a1 100644
--- a/tools/perf/util/Build
+++ b/tools/perf/util/Build
@@ -83,6 +83,7 @@ libperf-$(CONFIG_AUXTRACE) += intel-pt.o
 libperf-$(CONFIG_AUXTRACE) += intel-bts.o
 libperf-y += parse-branch-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 71d91fb..4343433 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -19,6 +19,7 @@
 #include "thread_map.h"
 #include "cpumap.h"
 #include "asm/bug.h"
+#include "bpf-loader.h"
 
 #define MAX_NAME_LEN 100
 
@@ -481,6 +482,45 @@ int parse_events_add_tracepoint(struct list_head *list, int *idx,
 		return add_tracepoint_event(list, idx, sys, event);
 }
 
+int parse_events_load_bpf(struct parse_events_evlist *data,
+			  struct list_head *list,
+			  char *bpf_file_name)
+{
+	int err;
+	char errbuf[BUFSIZ];
+	struct perf_evsel *evsel;
+
+	/*
+	 * Currently don't link useful event to list. BPF object files
+	 * should be saved to a seprated list and processed together.
+	 *
+	 * A dummy event is added here to collect '--filter' option.
+	 *
+	 * Things could be changed if we solve perf probe reentering
+	 * problem. After that probe events file by file is possible.
+	 * However, probing cost is still need to be considered.
+	 */
+	err = bpf__prepare_load(bpf_file_name);
+	if (err) {
+		bpf__strerror_prepare_load(bpf_file_name, err,
+					   errbuf, sizeof(errbuf));
+		data->error->str = strdup(errbuf);
+		data->error->help = strdup("(add -v to see detail)");
+		return err;
+	}
+
+	/*
+	 * Don't need call perf_evsel__init() for dummy evsel.
+	 * Also, don't increase data->idx.
+	 * data->idx affects other evsel's tracking field.
+	 */
+	evsel = perf_evsel__new_dummy(bpf_file_name);
+	if (!evsel)
+		return -ENOMEM;
+	list_add_tail(&evsel->node, list);
+	return 0;
+}
+
 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 a09b0e2..3652387 100644
--- a/tools/perf/util/parse-events.h
+++ b/tools/perf/util/parse-events.h
@@ -119,6 +119,9 @@ int parse_events__modifier_group(struct list_head *list, char *event_mod);
 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);
+int parse_events_load_bpf(struct parse_events_evlist *data,
+			  struct list_head *list,
+			  char *bpf_file_name);
 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 591905a..3ee3a32 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 '/'
@@ -420,6 +424,18 @@ PE_RAW
 	$$ = list;
 }
 
+event_bpf_file:
+PE_BPF_OBJECT
+{
+	struct parse_events_evlist *data = _data;
+	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;
-- 
2.1.0