Sender: Namhyung Kim <namhyung@gmail.com>
From:   Namhyung Kim <namhyung@kernel.org>
To:     Arnaldo Carvalho de Melo <acme@kernel.org>,
        Jiri Olsa <jolsa@kernel.org>, Ian Rogers <irogers@google.com>
Cc:     Ingo Molnar <mingo@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Adrian Hunter <adrian.hunter@intel.com>,
        linux-perf-users@vger.kernel.org
Subject: [PATCH] perf bpf filter: Add an error message for BPF filter
Date:   Fri, 17 Mar 2023 17:22:18 -0700
Message-Id: <20230318002218.2035109-1-namhyung@kernel.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Currently there's no error message for filter (other than the help for
the option) when it's built with NO_BPF_SKEL=1.  It should show the
BPF filter is not supported like below:

  $ sudo ./perf record -e cycles --filter ip==1 true
  BPF filter is not supported        <------------------- added

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

          --filter <filter>
                            event filter

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
 tools/perf/util/parse-events.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index 6c5cf5244486..f1fa469712c4 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -2543,8 +2543,16 @@ static int set_filter(struct evsel *evsel, const void *arg)
 		perf_pmu__scan_file(pmu, "nr_addr_filters",
 				    "%d", &nr_addr_filters);
 
-	if (!nr_addr_filters)
-		return perf_bpf_filter__parse(&evsel->bpf_filters, str);
+	if (!nr_addr_filters) {
+		int ret = perf_bpf_filter__parse(&evsel->bpf_filters, str);
+
+		if (ret == -EOPNOTSUPP)
+			fprintf(stderr, "BPF filter is not supported\n");
+		else if (ret)
+			fprintf(stderr, "failed to set the BPF filter\n");
+
+		return ret;
+	}
 
 	if (evsel__append_addr_filter(evsel, str) < 0) {
 		fprintf(stderr,
-- 
2.40.0.rc1.284.g88254d51c5-goog