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

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index b5b7967..9fdd839 100644 (file)
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -1532,6 +1532,7 @@ int bpf_prog_test_run_raw_tp(struct bpf_prog *prog,
 int bpf_prog_test_run_sk_lookup(struct bpf_prog *prog,
                                const union bpf_attr *kattr,
                                union bpf_attr __user *uattr);
+bool bpf_prog_test_check_kfunc_call(u32 kfunc_id);
 bool btf_ctx_access(int off, int size, enum bpf_access_type type,
                    const struct bpf_prog *prog,
                    struct bpf_insn_access_aux *info);
@@ -1731,6 +1732,11 @@ static inline int bpf_prog_test_run_sk_lookup(struct bpf_prog *prog,
        return -ENOTSUPP;
 }
 
+static inline bool bpf_prog_test_check_kfunc_call(u32 kfunc_id)
+{
+       return false;
+}
+
 static inline void bpf_map_put(struct bpf_map *map)
 {
 }

diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
index 4aabf71..a5d72c4 100644 (file)
--- a/net/bpf/test_run.c
+++ b/net/bpf/test_run.c
@@ -2,6 +2,7 @@
 /* Copyright (c) 2017 Facebook
  */
 #include <linux/bpf.h>
+#include <linux/btf_ids.h>
 #include <linux/slab.h>
 #include <linux/vmalloc.h>
 #include <linux/etherdevice.h>
@@ -213,10 +214,37 @@ int noinline bpf_modify_return_test(int a, int *b)
        *b += 1;
        return a + *b;
 }
+
+u64 noinline bpf_kfunc_call_test1(struct sock *sk, u32 a, u64 b, u32 c, u64 d)
+{
+       return a + b + c + d;
+}
+
+int noinline bpf_kfunc_call_test2(struct sock *sk, u32 a, u32 b)
+{
+       return a + b;
+}
+
+struct sock * noinline bpf_kfunc_call_test3(struct sock *sk)
+{
+       return sk;
+}
+
 __diag_pop();
 
 ALLOW_ERROR_INJECTION(bpf_modify_return_test, ERRNO);
 
+BTF_SET_START(test_sk_kfunc_ids)
+BTF_ID(func, bpf_kfunc_call_test1)
+BTF_ID(func, bpf_kfunc_call_test2)
+BTF_ID(func, bpf_kfunc_call_test3)
+BTF_SET_END(test_sk_kfunc_ids)
+
+bool bpf_prog_test_check_kfunc_call(u32 kfunc_id)
+{
+       return btf_id_set_contains(&test_sk_kfunc_ids, kfunc_id);
+}
+
 static void *bpf_test_init(const union bpf_attr *kattr, u32 size,
                           u32 headroom, u32 tailroom)
 {

diff --git a/net/core/filter.c b/net/core/filter.c
index 17dc159..cae56d0 100644 (file)
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -9813,6 +9813,7 @@ const struct bpf_verifier_ops tc_cls_act_verifier_ops = {
        .convert_ctx_access     = tc_cls_act_convert_ctx_access,
        .gen_prologue           = tc_cls_act_prologue,
        .gen_ld_abs             = bpf_gen_ld_abs,
+       .check_kfunc_call       = bpf_prog_test_check_kfunc_call,
 };
 
 const struct bpf_prog_ops tc_cls_act_prog_ops = {

diff --git a/tools/testing/selftests/bpf/prog_tests/kfunc_call.c b/tools/testing/selftests/bpf/prog_tests/kfunc_call.c
new file mode 100644 (file)
index 0000000..7fc0951
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/kfunc_call.c
@@ -0,0 +1,59 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2021 Facebook */
+#include <test_progs.h>
+#include <network_helpers.h>
+#include "kfunc_call_test.skel.h"
+#include "kfunc_call_test_subprog.skel.h"
+
+static void test_main(void)
+{
+       struct kfunc_call_test *skel;
+       int prog_fd, retval, err;
+
+       skel = kfunc_call_test__open_and_load();
+       if (!ASSERT_OK_PTR(skel, "skel"))
+               return;
+
+       prog_fd = bpf_program__fd(skel->progs.kfunc_call_test1);
+       err = bpf_prog_test_run(prog_fd, 1, &pkt_v4, sizeof(pkt_v4),
+                               NULL, NULL, (__u32 *)&retval, NULL);
+       ASSERT_OK(err, "bpf_prog_test_run(test1)");
+       ASSERT_EQ(retval, 12, "test1-retval");
+
+       prog_fd = bpf_program__fd(skel->progs.kfunc_call_test2);
+       err = bpf_prog_test_run(prog_fd, 1, &pkt_v4, sizeof(pkt_v4),
+                               NULL, NULL, (__u32 *)&retval, NULL);
+       ASSERT_OK(err, "bpf_prog_test_run(test2)");
+       ASSERT_EQ(retval, 3, "test2-retval");
+
+       kfunc_call_test__destroy(skel);
+}
+
+static void test_subprog(void)
+{
+       struct kfunc_call_test_subprog *skel;
+       int prog_fd, retval, err;
+
+       skel = kfunc_call_test_subprog__open_and_load();
+       if (!ASSERT_OK_PTR(skel, "skel"))
+               return;
+
+       prog_fd = bpf_program__fd(skel->progs.kfunc_call_test1);
+       err = bpf_prog_test_run(prog_fd, 1, &pkt_v4, sizeof(pkt_v4),
+                               NULL, NULL, (__u32 *)&retval, NULL);
+       ASSERT_OK(err, "bpf_prog_test_run(test1)");
+       ASSERT_EQ(retval, 10, "test1-retval");
+       ASSERT_NEQ(skel->data->active_res, -1, "active_res");
+       ASSERT_EQ(skel->data->sk_state, BPF_TCP_CLOSE, "sk_state");
+
+       kfunc_call_test_subprog__destroy(skel);
+}
+
+void test_kfunc_call(void)
+{
+       if (test__start_subtest("main"))
+               test_main();
+
+       if (test__start_subtest("subprog"))
+               test_subprog();
+}

diff --git a/tools/testing/selftests/bpf/progs/kfunc_call_test.c b/tools/testing/selftests/bpf/progs/kfunc_call_test.c
new file mode 100644 (file)
index 0000000..470f872
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/kfunc_call_test.c
@@ -0,0 +1,47 @@
+// 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 int bpf_kfunc_call_test2(struct sock *sk, __u32 a, __u32 b) __ksym;
+extern __u64 bpf_kfunc_call_test1(struct sock *sk, __u32 a, __u64 b,
+                                 __u32 c, __u64 d) __ksym;
+
+SEC("classifier")
+int kfunc_call_test2(struct __sk_buff *skb)
+{
+       struct bpf_sock *sk = skb->sk;
+
+       if (!sk)
+               return -1;
+
+       sk = bpf_sk_fullsock(sk);
+       if (!sk)
+               return -1;
+
+       return bpf_kfunc_call_test2((struct sock *)sk, 1, 2);
+}
+
+SEC("classifier")
+int kfunc_call_test1(struct __sk_buff *skb)
+{
+       struct bpf_sock *sk = skb->sk;
+       __u64 a = 1ULL << 32;
+       __u32 ret;
+
+       if (!sk)
+               return -1;
+
+       sk = bpf_sk_fullsock(sk);
+       if (!sk)
+               return -1;
+
+       a = bpf_kfunc_call_test1((struct sock *)sk, 1, a | 2, 3, a | 4);
+       ret = a >> 32;   /* ret should be 2 */
+       ret += (__u32)a; /* ret should be 12 */
+
+       return ret;
+}
+
+char _license[] SEC("license") = "GPL";

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 (file)
index 0000000..b2dcb7d
--- /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";