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Message-Id: <20200702134930.4717-6-maciej.fijalkowski@intel.com>
Date: Thu, 2 Jul 2020 15:49:30 +0200
From: Maciej Fijalkowski <maciej.fijalkowski@...el.com>
To: ast@...nel.org, daniel@...earbox.net
Cc: bpf@...r.kernel.org, netdev@...r.kernel.org, bjorn.topel@...el.com,
magnus.karlsson@...el.com,
Maciej Fijalkowski <maciej.fijalkowski@...el.com>
Subject: [RFC PATCH bpf-next 5/5] selftests: bpf: add dummy prog for bpf2bpf with tailcall
Introduce 6th test to taicalls kselftest that checks if tailcall can be
correctly executed from the BPF subprogram.
Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@...el.com>
---
.../selftests/bpf/prog_tests/tailcalls.c | 85 +++++++++++++++++++
tools/testing/selftests/bpf/progs/tailcall6.c | 38 +++++++++
2 files changed, 123 insertions(+)
create mode 100644 tools/testing/selftests/bpf/progs/tailcall6.c
diff --git a/tools/testing/selftests/bpf/prog_tests/tailcalls.c b/tools/testing/selftests/bpf/prog_tests/tailcalls.c
index bb8fe646dd9f..192c94896809 100644
--- a/tools/testing/selftests/bpf/prog_tests/tailcalls.c
+++ b/tools/testing/selftests/bpf/prog_tests/tailcalls.c
@@ -1,5 +1,6 @@
// SPDX-License-Identifier: GPL-2.0
#include <test_progs.h>
+#include <network_helpers.h>
/* test_tailcall_1 checks basic functionality by patching multiple locations
* in a single program for a single tail call slot with nop->jmp, jmp->nop
@@ -472,6 +473,88 @@ static void test_tailcall_5(void)
bpf_object__close(obj);
}
+/* test_tailcall_6 purpose is to make sure that tailcalls are working
+ * correctly in correlation with BPF subprograms
+ */
+static void test_tailcall_6(void)
+{
+ int err, map_fd, prog_fd, main_fd, i;
+ struct bpf_map *prog_array;
+ struct bpf_program *prog;
+ struct bpf_object *obj;
+ __u32 retval, duration;
+ char prog_name[32];
+
+ err = bpf_prog_load("tailcall6.o", BPF_PROG_TYPE_SCHED_CLS, &obj,
+ &prog_fd);
+ if (CHECK_FAIL(err))
+ return;
+
+ prog = bpf_object__find_program_by_title(obj, "classifier");
+ if (CHECK_FAIL(!prog))
+ goto out;
+
+ main_fd = bpf_program__fd(prog);
+ if (CHECK_FAIL(main_fd < 0))
+ goto out;
+
+ prog_array = bpf_object__find_map_by_name(obj, "jmp_table");
+ if (CHECK_FAIL(!prog_array))
+ goto out;
+
+ map_fd = bpf_map__fd(prog_array);
+ if (CHECK_FAIL(map_fd < 0))
+ goto out;
+
+ /* nop -> jmp */
+ for (i = 0; i < bpf_map__def(prog_array)->max_entries; i++) {
+ snprintf(prog_name, sizeof(prog_name), "classifier/%i", i);
+
+ prog = bpf_object__find_program_by_title(obj, prog_name);
+ if (CHECK_FAIL(!prog))
+ goto out;
+
+ prog_fd = bpf_program__fd(prog);
+ if (CHECK_FAIL(prog_fd < 0))
+ goto out;
+
+ err = bpf_map_update_elem(map_fd, &i, &prog_fd, BPF_ANY);
+ if (CHECK_FAIL(err))
+ goto out;
+ }
+
+ err = bpf_prog_test_run(main_fd, 1, &pkt_v4, sizeof(pkt_v4), 0,
+ 0, &retval, &duration);
+ CHECK(err || retval != 1, "tailcall",
+ "err %d errno %d retval %d\n", err, errno, retval);
+
+ /* jmp -> nop, call subprog that will do tailcall */
+ i = 1;
+ err = bpf_map_delete_elem(map_fd, &i);
+ if (CHECK_FAIL(err))
+ goto out;
+
+ err = bpf_prog_test_run(main_fd, 1, &pkt_v4, sizeof(pkt_v4), 0,
+ 0, &retval, &duration);
+ CHECK(err || retval != 0, "tailcall", "err %d errno %d retval %d\n",
+ err, errno, retval);
+
+ /* make sure that subprog can access ctx and entry prog that
+ * called this subprog can properly return
+ */
+ i = 0;
+ err = bpf_map_delete_elem(map_fd, &i);
+ if (CHECK_FAIL(err))
+ goto out;
+
+ err = bpf_prog_test_run(main_fd, 1, &pkt_v4, sizeof(pkt_v4), 0,
+ 0, &retval, &duration);
+ CHECK(err || retval != 108, "tailcall", "err %d errno %d retval %d\n",
+ err, errno, retval);
+out:
+ bpf_object__close(obj);
+}
+
void test_tailcalls(void)
{
if (test__start_subtest("tailcall_1"))
@@ -484,4 +567,6 @@ void test_tailcalls(void)
test_tailcall_4();
if (test__start_subtest("tailcall_5"))
test_tailcall_5();
+ if (test__start_subtest("tailcall_6"))
+ test_tailcall_6();
}
diff --git a/tools/testing/selftests/bpf/progs/tailcall6.c b/tools/testing/selftests/bpf/progs/tailcall6.c
new file mode 100644
index 000000000000..e72ca5869b58
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/tailcall6.c
@@ -0,0 +1,38 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+
+struct {
+ __uint(type, BPF_MAP_TYPE_PROG_ARRAY);
+ __uint(max_entries, 2);
+ __uint(key_size, sizeof(__u32));
+ __uint(value_size, sizeof(__u32));
+} jmp_table SEC(".maps");
+
+#define TAIL_FUNC(x) \
+ SEC("classifier/" #x) \
+ int bpf_func_##x(struct __sk_buff *skb) \
+ { \
+ return x; \
+ }
+TAIL_FUNC(0)
+TAIL_FUNC(1)
+
+static __attribute__ ((noinline))
+int subprog_tail(struct __sk_buff *skb)
+{
+ bpf_tail_call(skb, &jmp_table, 0);
+
+ return skb->len * 2;
+}
+
+SEC("classifier")
+int entry(struct __sk_buff *skb)
+{
+ bpf_tail_call(skb, &jmp_table, 1);
+
+ return subprog_tail(skb);
+}
+
+char __license[] SEC("license") = "GPL";
+int _version SEC("version") = 1;
--
2.20.1
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