selftests/bpf: add few verifier scale tests

Add 3 basic tests that stress verifier scalability.

test_verif_scale1.c calls non-inlined jhash() function 90 times on
different position in the packet.
This test simulates network packet parsing.
jhash function is ~140 instructions and main program is ~1200 insns.

test_verif_scale2.c force inlines jhash() function 90 times.
This program is ~15k instructions long.

test_verif_scale3.c calls non-inlined jhash() function 90 times on
But this time jhash has to process 32-bytes from the packet
instead of 14-bytes in tests 1 and 2.
jhash function is ~230 insns and main program is ~1200 insns.

$ test_progs -s
can be used to see verifier stats.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

1 files changed, 49 insertions, 0 deletions

diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_verif_scale.c b/tools/testing/selftests/bpf/prog_tests/bpf_verif_scale.c
new file mode 100644
index 000000000000..23b159d95c3f
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/bpf_verif_scale.c
@@ -0,0 +1,49 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2019 Facebook
+#include <test_progs.h>
+static int libbpf_debug_print(enum libbpf_print_level level,
+			      const char *format, va_list args)
+{
+	if (level != LIBBPF_DEBUG)
+		return 0;
+
+	if (!strstr(format, "verifier log"))
+		return 0;
+	return vfprintf(stderr, "%s", args);
+}
+
+static int check_load(const char *file)
+{
+	struct bpf_prog_load_attr attr;
+	struct bpf_object *obj;
+	int err, prog_fd;
+
+	memset(&attr, 0, sizeof(struct bpf_prog_load_attr));
+	attr.file = file;
+	attr.prog_type = BPF_PROG_TYPE_SCHED_CLS;
+	attr.log_level = 4;
+	err = bpf_prog_load_xattr(&attr, &obj, &prog_fd);
+	bpf_object__close(obj);
+	if (err)
+		error_cnt++;
+	return err;
+}
+
+void test_bpf_verif_scale(void)
+{
+	const char *file1 = "./test_verif_scale1.o";
+	const char *file2 = "./test_verif_scale2.o";
+	const char *file3 = "./test_verif_scale3.o";
+	int err;
+
+	if (verifier_stats)
+		libbpf_set_print(libbpf_debug_print);
+
+	err = check_load(file1);
+	err |= check_load(file2);
+	err |= check_load(file3);
+	if (!err)
+		printf("test_verif_scale:OK\n");
+	else
+		printf("test_verif_scale:FAIL\n");
+}