Add a test that implements a BPF program writing to a test map, which
is attached to RTLA via --bpf-action to be executed on theshold
overflow.

A combination of --on-threshold shell with bpftool (which is always
present if BPF support is enabled) is used to check whether the BPF
program has executed successfully.

Suggested-by: Crystal Wood <[email protected]>
Signed-off-by: Tomas Glozar <[email protected]>
---
 tools/tracing/rtla/Makefile                   | 10 ++++++--
 tools/tracing/rtla/tests/bpf/bpf_action_map.c | 25 +++++++++++++++++++
 tools/tracing/rtla/tests/timerlat.t           | 15 +++++++++++
 3 files changed, 48 insertions(+), 2 deletions(-)
 create mode 100644 tools/tracing/rtla/tests/bpf/bpf_action_map.c

diff --git a/tools/tracing/rtla/Makefile b/tools/tracing/rtla/Makefile
index 5f1529ce3693..aef814b639b7 100644
--- a/tools/tracing/rtla/Makefile
+++ b/tools/tracing/rtla/Makefile
@@ -76,12 +76,18 @@ src/timerlat.skel.h: src/timerlat.bpf.o
 
 example/timerlat_bpf_action.o: example/timerlat_bpf_action.c
        $(QUIET_CLANG)$(CLANG) -g -O2 -target bpf -c $(filter %.c,$^) -o $@
+
+tests/bpf/bpf_action_map.o: tests/bpf/bpf_action_map.c
+       $(QUIET_CLANG)$(CLANG) -g -O2 -target bpf -c $(filter %.c,$^) -o $@
 else
 src/timerlat.skel.h:
        $(Q)echo '/* BPF skeleton is disabled */' > src/timerlat.skel.h
 
 example/timerlat_bpf_action.o: example/timerlat_bpf_action.c
        $(Q)echo "BPF skeleton support is disabled, skipping 
example/timerlat_bpf_action.o"
+
+tests/bpf/bpf_action_map.o: tests/bpf/bpf_action_map.c
+       $(Q)echo "BPF skeleton support is disabled, skipping 
tests/bpf/bpf_action_map.o"
 endif
 
 $(RTLA): $(RTLA_IN)
@@ -103,7 +109,7 @@ clean: doc_clean fixdep-clean
        $(Q)rm -f rtla rtla-static fixdep FEATURE-DUMP rtla-*
        $(Q)rm -rf feature
        $(Q)rm -f src/timerlat.bpf.o src/timerlat.skel.h 
example/timerlat_bpf_action.o
-check: $(RTLA)
-       RTLA=$(RTLA) prove -o -f tests/
+check: $(RTLA) tests/bpf/bpf_action_map.o
+       RTLA=$(RTLA) BPFTOOL=$(SYSTEM_BPFTOOL) prove -o -f tests/
 examples: example/timerlat_bpf_action.o
 .PHONY: FORCE clean check
diff --git a/tools/tracing/rtla/tests/bpf/bpf_action_map.c 
b/tools/tracing/rtla/tests/bpf/bpf_action_map.c
new file mode 100644
index 000000000000..1686e0b858e6
--- /dev/null
+++ b/tools/tracing/rtla/tests/bpf/bpf_action_map.c
@@ -0,0 +1,25 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/bpf.h>
+#include <bpf/bpf_tracing.h>
+
+char LICENSE[] SEC("license") = "GPL";
+
+struct {
+       __uint(type, BPF_MAP_TYPE_ARRAY);
+       __uint(max_entries, 1);
+       __type(key, unsigned int);
+       __type(value, unsigned long long);
+} rtla_test_map SEC(".maps");
+
+struct trace_event_raw_timerlat_sample;
+
+SEC("tp/timerlat_action")
+int action_handler(struct trace_event_raw_timerlat_sample *tp_args)
+{
+       unsigned int key = 0;
+       unsigned long long value = 42;
+
+       bpf_map_update_elem(&rtla_test_map, &key, &value, BPF_ANY);
+
+       return 0;
+}
diff --git a/tools/tracing/rtla/tests/timerlat.t 
b/tools/tracing/rtla/tests/timerlat.t
index bbaa1897d8a8..fd4935fd7b49 100644
--- a/tools/tracing/rtla/tests/timerlat.t
+++ b/tools/tracing/rtla/tests/timerlat.t
@@ -67,6 +67,21 @@ check "hist with trace output at end" \
        "timerlat hist -d 1s --on-end trace" 0 "^  Saving trace to 
timerlat_trace.txt$"
 check "top with trace output at end" \
        "timerlat top -d 1s --on-end trace" 0 "^  Saving trace to 
timerlat_trace.txt$"
+
+# BPF action program tests
+if [ "$option" -eq 0 ]
+then
+       # Test BPF action program properly in BPF mode
+       [ -z "$BPFTOOL" ] && BPFTOOL=bpftool
+       check "hist with BPF action program (BPF mode)" \
+               "timerlat hist -T 2 --bpf-action tests/bpf/bpf_action_map.o 
--on-threshold shell,command='$BPFTOOL map dump name rtla_test_map'" \
+               2 '"value": 42'
+else
+       # Test BPF action program failure in non-BPF mode
+       check "hist with BPF action program (non-BPF mode)" \
+               "timerlat hist -T 2 --bpf-action tests/bpf/bpf_action_map.o" \
+               1 "BPF actions are not supported in tracefs-only mode"
+fi
 done
 
 test_end
-- 
2.51.1


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