[PATCH bpf-next 3/3] selftests/bpf: Add a selftest for the KF_DEPRECATED kfunc flag

[David Vernet <void@manifault.com>]

Now that we have KF_DEPRECATED, we should add a selftest for it. This
patch implements that selftest by adding a new test
bpf_kfunc_call_test_deprecated() that includes the KF_DEPRECATED flag,
and adding a kfunc_call_test_deprecated testcase to the kfunc_call_test
suite which verifies that the program is loaded and has the expected
verifier error message.

Signed-off-by: David Vernet <void@manifault.com>
---
 net/bpf/test_run.c                                  |  5 +++++
 tools/testing/selftests/bpf/prog_tests/kfunc_call.c |  2 ++
 tools/testing/selftests/bpf/progs/kfunc_call_test.c | 10 ++++++++++
 3 files changed, 17 insertions(+)

diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
index e6f773d12045..945d6f7c1825 100644
--- a/net/bpf/test_run.c
+++ b/net/bpf/test_run.c
@@ -746,6 +746,10 @@ __bpf_kfunc static u32 bpf_kfunc_call_test_static_unused_arg(u32 arg, u32 unused
 	return arg;
 }
 
+__bpf_kfunc void bpf_kfunc_call_test_deprecated(void)
+{
+}
+
 __diag_pop();
 
 BTF_SET8_START(bpf_test_modify_return_ids)
@@ -785,6 +789,7 @@ BTF_ID_FLAGS(func, bpf_kfunc_call_test_mem_len_fail2)
 BTF_ID_FLAGS(func, bpf_kfunc_call_test_ref, KF_TRUSTED_ARGS)
 BTF_ID_FLAGS(func, bpf_kfunc_call_test_destructive, KF_DESTRUCTIVE)
 BTF_ID_FLAGS(func, bpf_kfunc_call_test_static_unused_arg)
+BTF_ID_FLAGS(func, bpf_kfunc_call_test_deprecated, KF_DEPRECATED)
 BTF_SET8_END(test_sk_check_kfunc_ids)
 
 static void *bpf_test_init(const union bpf_attr *kattr, u32 user_size,
diff --git a/tools/testing/selftests/bpf/prog_tests/kfunc_call.c b/tools/testing/selftests/bpf/prog_tests/kfunc_call.c
index a543742cd7bd..98398dba5718 100644
--- a/tools/testing/selftests/bpf/prog_tests/kfunc_call.c
+++ b/tools/testing/selftests/bpf/prog_tests/kfunc_call.c
@@ -319,4 +319,6 @@ void test_kfunc_call(void)
 
 	if (test__start_subtest("destructive"))
 		test_destructive();
+
+	RUN_TESTS(kfunc_call_test);
 }
diff --git a/tools/testing/selftests/bpf/progs/kfunc_call_test.c b/tools/testing/selftests/bpf/progs/kfunc_call_test.c
index 7daa8f5720b9..b605438e42dd 100644
--- a/tools/testing/selftests/bpf/progs/kfunc_call_test.c
+++ b/tools/testing/selftests/bpf/progs/kfunc_call_test.c
@@ -2,6 +2,7 @@
 /* Copyright (c) 2021 Facebook */
 #include <vmlinux.h>
 #include <bpf/bpf_helpers.h>
+#include "bpf_misc.h"
 
 extern long bpf_kfunc_call_test4(signed char a, short b, int c, long d) __ksym;
 extern int bpf_kfunc_call_test2(struct sock *sk, __u32 a, __u32 b) __ksym;
@@ -18,6 +19,7 @@ extern void bpf_kfunc_call_test_mem_len_fail2(__u64 *mem, int len) __ksym;
 extern int *bpf_kfunc_call_test_get_rdwr_mem(struct prog_test_ref_kfunc *p, const int rdwr_buf_size) __ksym;
 extern int *bpf_kfunc_call_test_get_rdonly_mem(struct prog_test_ref_kfunc *p, const int rdonly_buf_size) __ksym;
 extern u32 bpf_kfunc_call_test_static_unused_arg(u32 arg, u32 unused) __ksym;
+extern void bpf_kfunc_call_test_deprecated(void) __ksym;
 
 SEC("tc")
 int kfunc_call_test4(struct __sk_buff *skb)
@@ -192,4 +194,12 @@ int kfunc_call_test_static_unused_arg(struct __sk_buff *skb)
 	return actual != expected ? -1 : 0;
 }
 
+SEC("tc")
+__success __log_level(2) __msg("calling deprecated kfunc bpf_kfunc_call_test_deprecated")
+int kfunc_call_test_deprecated(struct __sk_buff *skb)
+{
+	bpf_kfunc_call_test_deprecated();
+	return 0;
+}
+
 char _license[] SEC("license") = "GPL";
-- 
2.39.0