perf tools: Enable BPF object configure syntax

This patch adds the final step for BPF map configuration. A new syntax
is appended into parser so user can config BPF objects through '/' '/'
enclosed config terms.

After this patch, following syntax is available:

  # perf record -e ./test_bpf_map_1.c/map:channel.value=10/ ...

It would takes effect after appling following commits.

Test result:

  # cat ./test_bpf_map_1.c
  /************************ BEGIN **************************/
  #include <uapi/linux/bpf.h>
  #define SEC(NAME) __attribute__((section(NAME), used))
  struct bpf_map_def {
      unsigned int type;
      unsigned int key_size;
      unsigned int value_size;
      unsigned int max_entries;
  };
  static void *(*map_lookup_elem)(struct bpf_map_def *, void *) =
      (void *)BPF_FUNC_map_lookup_elem;
  static int (*trace_printk)(const char *fmt, int fmt_size, ...) =
      (void *)BPF_FUNC_trace_printk;
  struct bpf_map_def SEC("maps") channel = {
      .type = BPF_MAP_TYPE_ARRAY,
      .key_size = sizeof(int),
      .value_size = sizeof(int),
      .max_entries = 1,
  };
  SEC("func=sys_nanosleep")
  int func(void *ctx)
  {
      int key = 0;
      char fmt[] = "%d\n";
      int *pval = map_lookup_elem(&channel, &key);
      if (!pval)
          return 0;
      trace_printk(fmt, sizeof(fmt), *pval);
      return 0;
  }
  char _license[] SEC("license") = "GPL";
  int _version SEC("version") = LINUX_VERSION_CODE;
  /************************* END ***************************/

 - Normal case:
  # ./perf record -e './test_bpf_map_1.c/map:channel.value=10/' usleep 10
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.012 MB perf.data ]

 - Error case:

  # ./perf record -e './test_bpf_map_1.c/map:channel.value/' usleep 10
  event syntax error: '..ps:channel:value/'
                                   \___ Config value not set (missing '=')
  Hint:	Valid config term:
         map:[<arraymap>]:value=[value]
         (add -v to see detail)
  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

  # ./perf record -e './test_bpf_map_1.c/xmap:channel.value=10/' usleep 10
  event syntax error: '..pf_map_1.c/xmap:channel.value=10/'
                                    \___ Invalid object config option
  [SNIP]

  # ./perf record -e './test_bpf_map_1.c/map:xchannel.value=10/' usleep 10
  event syntax error: '..p_1.c/map:xchannel.value=10/'
                                    \___ Target map not exist
  [SNIP]

  # ./perf record -e './test_bpf_map_1.c/map:channel.xvalue=10/' usleep 10
  event syntax error: '..ps:channel.xvalue=10/'
                                    \___ Invalid object map config option
  [SNIP]

  # ./perf record -e './test_bpf_map_1.c/map:channel.value=x10/' usleep 10
  event syntax error: '..nnel.value=x10/'
                                    \___ Incorrect value type for map
  [SNIP]

  Change BPF_MAP_TYPE_ARRAY to '1' in test_bpf_map_1.c:

  # ./perf record -e './test_bpf_map_1.c/map:channel.value=10/' usleep 10
  event syntax error: '..ps:channel.value=10/'
                                    \___ Can't use this config term to this type of map

  Hint:	Valid config term:
      	map:[<arraymap>].value=[value]
      	(add -v to see detail)

Signed-off-by: Wang Nan <wangnan0@huawei.com>
[for parser part]
Acked-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Cody P Schafer <dev@codyps.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jeremie Galarneau <jeremie.galarneau@efficios.com>
Cc: Kirill Smelkov <kirr@nexedi.com>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1456132275-98875-5-git-send-email-wangnan0@huawei.com
Signed-off-by: He Kuang <hekuang@huawei.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 52 insertions, 3 deletions

diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index b0b329539db5..a5dd6703a56b 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -672,17 +672,63 @@ errout:
 	return err;
 }
 
+static int
+parse_events_config_bpf(struct parse_events_evlist *data,
+			struct bpf_object *obj,
+			struct list_head *head_config)
+{
+	struct parse_events_term *term;
+	int error_pos;
+
+	if (!head_config || list_empty(head_config))
+		return 0;
+
+	list_for_each_entry(term, head_config, list) {
+		char errbuf[BUFSIZ];
+		int err;
+
+		if (term->type_term != PARSE_EVENTS__TERM_TYPE_USER) {
+			snprintf(errbuf, sizeof(errbuf),
+				 "Invalid config term for BPF object");
+			errbuf[BUFSIZ - 1] = '\0';
+
+			data->error->idx = term->err_term;
+			data->error->str = strdup(errbuf);
+			return -EINVAL;
+		}
+
+		err = bpf__config_obj(obj, term, NULL, &error_pos);
+		if (err) {
+			bpf__strerror_config_obj(obj, term, NULL,
+						 &error_pos, err, errbuf,
+						 sizeof(errbuf));
+			data->error->help = strdup(
+"Hint:\tValid config term:\n"
+"     \tmap:[<arraymap>].value=[value]\n"
+"     \t(add -v to see detail)");
+			data->error->str = strdup(errbuf);
+			if (err == -BPF_LOADER_ERRNO__OBJCONF_MAP_VALUE)
+				data->error->idx = term->err_val;
+			else
+				data->error->idx = term->err_term + error_pos;
+			return err;
+		}
+	}
+	return 0;
+}
+
 int parse_events_load_bpf(struct parse_events_evlist *data,
 			  struct list_head *list,
 			  char *bpf_file_name,
-			  bool source)
+			  bool source,
+			  struct list_head *head_config)
 {
 	struct bpf_object *obj;
+	int err;
 
 	obj = bpf__prepare_load(bpf_file_name, source);
 	if (IS_ERR(obj)) {
 		char errbuf[BUFSIZ];
-		int err;
 
 		err = PTR_ERR(obj);
 
@@ -700,7 +746,10 @@ int parse_events_load_bpf(struct parse_events_evlist *data,
 		return err;
 	}
 
-	return parse_events_load_bpf_obj(data, list, obj);
+	err = parse_events_load_bpf_obj(data, list, obj);
+	if (err)
+		return err;
+	return parse_events_config_bpf(data, obj, head_config);
 }
 
 static int