bpf: selftests: Add kfunc_call test

This patch adds a few kernel function bpf_kfunc_call_test*() for the
selftest's test_run purpose.  They will be allowed for tc_cls prog.

The selftest calling the kernel function bpf_kfunc_call_test*()
is also added in this patch.

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210325015252.1551395-1-kafai@fb.com

1 files changed, 42 insertions, 0 deletions

diff --git a/tools/testing/selftests/bpf/progs/kfunc_call_test_subprog.c b/tools/testing/selftests/bpf/progs/kfunc_call_test_subprog.c
new file mode 100644
index 000000000000..b2dcb7d9cb03
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/kfunc_call_test_subprog.c
@@ -0,0 +1,42 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2021 Facebook */
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+#include "bpf_tcp_helpers.h"
+
+extern const int bpf_prog_active __ksym;
+extern __u64 bpf_kfunc_call_test1(struct sock *sk, __u32 a, __u64 b,
+				  __u32 c, __u64 d) __ksym;
+extern struct sock *bpf_kfunc_call_test3(struct sock *sk) __ksym;
+int active_res = -1;
+int sk_state = -1;
+
+int __noinline f1(struct __sk_buff *skb)
+{
+	struct bpf_sock *sk = skb->sk;
+	int *active;
+
+	if (!sk)
+		return -1;
+
+	sk = bpf_sk_fullsock(sk);
+	if (!sk)
+		return -1;
+
+	active = (int *)bpf_per_cpu_ptr(&bpf_prog_active,
+					bpf_get_smp_processor_id());
+	if (active)
+		active_res = *active;
+
+	sk_state = bpf_kfunc_call_test3((struct sock *)sk)->__sk_common.skc_state;
+
+	return (__u32)bpf_kfunc_call_test1((struct sock *)sk, 1, 2, 3, 4);
+}
+
+SEC("classifier")
+int kfunc_call_test1(struct __sk_buff *skb)
+{
+	return f1(skb);
+}
+
+char _license[] SEC("license") = "GPL";