perf test arm64: Test unwinding using fame-pointer (fp) mode

Add a shell script to check that the call-graphs generated using frame
pointers (--call-graph fp) are complete and not missing leaf functions:

  | $ perf test 88 -v
  |  88: Check Arm64 callgraphs are complete in fp mode                  :
  | --- start ---
  | test child forked, pid 8734
  |  + Compiling test program (/tmp/test_program.Cz3yL)...
  |  + Recording (PID=8749)...
  |  + Stopping perf-record...
  | test_program.Cz
  |                  728 leaf
  |                  753 parent
  |                  76c main
  | test child finished with 0
  | ---- end ----
  | Check Arm SPE callgraphs are complete in fp mode: Ok

It's supposed to work with both unwinders:

  | $ make                # for libunwind (default)
  | $ make NO_LIBUNWIND=1 # for libdw

Tester notes:

Ran it on N1SDP and it passes, and it fails if b9f6fbb3b2 ("perf
arm64: Inject missing frames when using 'perf record --call-graph=fp'")
isn't applied.

Fixes: b9f6fbb3b2 ("perf arm64: Inject missing frames when using 'perf record --call-graph=fp'")
Suggested-by: Jiri Olsa <[email protected]>
Reviewed-by: James Clark <[email protected]>
Tested-by: James Clark <[email protected]>
Signed-off-by: German Gomez <[email protected]>
Cc: Alexandre Truong <[email protected]>
Cc: Leo Yan <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Namhyung Kim <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

tools/perf/tests/shell/test_arm_callgraph_fp.sh

@@ -0,0 +1,68 @@
+#!/bin/sh
+# Check Arm64 callgraphs are complete in fp mode
+# SPDX-License-Identifier: GPL-2.0
+
+lscpu | grep -q "aarch64" || exit 2
+
+if ! [ -x "$(command -v cc)" ]; then
+	echo "failed: no compiler, install gcc"
+	exit 2
+fi
+
+PERF_DATA=$(mktemp /tmp/__perf_test.perf.data.XXXXX)
+TEST_PROGRAM_SOURCE=$(mktemp /tmp/test_program.XXXXX.c)
+TEST_PROGRAM=$(mktemp /tmp/test_program.XXXXX)
+
+cleanup_files()
+{
+	rm -f $PERF_DATA
+	rm -f $TEST_PROGRAM_SOURCE
+	rm -f $TEST_PROGRAM
+}
+
+trap cleanup_files exit term int
+
+cat << EOF > $TEST_PROGRAM_SOURCE
+int a = 0;
+void leaf(void) {
+  for (;;)
+    a += a;
+}
+void parent(void) {
+  leaf();
+}
+int main(void) {
+  parent();
+  return 0;
+}
+EOF
+
+echo " + Compiling test program ($TEST_PROGRAM)..."
+
+CFLAGS="-g -O0 -fno-inline -fno-omit-frame-pointer"
+cc $CFLAGS $TEST_PROGRAM_SOURCE -o $TEST_PROGRAM || exit 1
+
+# Add a 1 second delay to skip samples that are not in the leaf() function
+perf record -o $PERF_DATA --call-graph fp -e cycles//u -D 1000 -- $TEST_PROGRAM 2> /dev/null &
+PID=$!
+
+echo " + Recording (PID=$PID)..."
+sleep 2
+echo " + Stopping perf-record..."
+
+kill $PID
+wait $PID
+
+# expected perf-script output:
+#
+# program
+# 	728 leaf
+# 	753 parent
+# 	76c main
+# ...
+
+perf script -i $PERF_DATA -F comm,ip,sym | head -n4
+perf script -i $PERF_DATA -F comm,ip,sym | head -n4 | \
+	awk '{ if ($2 != "") sym[i++] = $2 } END { if (sym[0] != "leaf" ||
+						       sym[1] != "parent" ||
+						       sym[2] != "main") exit 1 }'