selftests/bpf: Add bpf_copy_branch_snapshot test

Add test case for bpf_copy_branch_snapshot kfunc by reusing the one of
bpf_get_branch_snapshot helper.

Signed-off-by: Leon Hwang <[email protected]>

Author: Asphaltt

tools/testing/selftests/bpf/prog_tests/get_branch_snapshot.c

@@ -73,7 +73,7 @@ static void close_perf_events(void)
 	free(pfd_array);
 }
 
-void serial_test_get_branch_snapshot(void)
+static void test_branch_snapshot(int test_copy_branch_snapshot)
 {
 	struct get_branch_snapshot *skel = NULL;
 	int err;
@@ -93,6 +93,8 @@ void serial_test_get_branch_snapshot(void)
 	if (!ASSERT_OK_PTR(skel, "get_branch_snapshot__open_and_load"))
 		goto cleanup;
 
+	skel->bss->copy_branch_snapshot = test_copy_branch_snapshot;
+
 	err = kallsyms_find("bpf_testmod_loop_test", &skel->bss->address_low);
 	if (!ASSERT_OK(err, "kallsyms_find"))
 		goto cleanup;
@@ -128,3 +130,13 @@ void serial_test_get_branch_snapshot(void)
 	get_branch_snapshot__destroy(skel);
 	close_perf_events();
 }
+
+void serial_test_get_branch_snapshot(void)
+{
+	test_branch_snapshot(0);
+}
+
+void serial_test_copy_branch_snapshot(void)
+{
+	test_branch_snapshot(1);
+}

tools/testing/selftests/bpf/progs/get_branch_snapshot.c

@@ -9,6 +9,7 @@ char _license[] SEC("license") = "GPL";
 __u64 test1_hits = 0;
 __u64 address_low = 0;
 __u64 address_high = 0;
+int copy_branch_snapshot = 0;
 int wasted_entries = 0;
 long total_entries = 0;
 
@@ -25,7 +26,10 @@ int BPF_PROG(test1, int n, int ret)
 {
 	long i;
 
-	total_entries = bpf_get_branch_snapshot(entries, sizeof(entries), 0);
+	if (copy_branch_snapshot)
+		total_entries = bpf_copy_branch_snapshot(ctx, entries, sizeof(entries), 0);
+	else
+		total_entries = bpf_get_branch_snapshot(entries, sizeof(entries), 0);
 	total_entries /= sizeof(struct perf_branch_entry);
 
 	for (i = 0; i < ENTRY_CNT; i++) {