Add several BPF kselftest cases for tail calls which test the various
patch directions (NOP -> JMP, JMP -> JMP, JMP -> NOP), and that multiple
locations are patched.
# ./test_progs -n 44
#44 tailcalls:OK
Summary: 1/0 PASSED, 0 SKIPPED, 0 FAILED
Signed-off-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
---
.../selftests/bpf/prog_tests/tailcalls.c | 210 ++++++++++++++++++
tools/testing/selftests/bpf/progs/tailcall1.c | 48 ++++
tools/testing/selftests/bpf/progs/tailcall2.c | 59 +++++
3 files changed, 317 insertions(+)
create mode 100644 tools/testing/selftests/bpf/prog_tests/tailcalls.c
create mode 100644 tools/testing/selftests/bpf/progs/tailcall1.c
create mode 100644 tools/testing/selftests/bpf/progs/tailcall2.c
diff --git a/tools/testing/selftests/bpf/prog_tests/tailcalls.c b/tools/testing/selftests/bpf/prog_tests/tailcalls.c
new file mode 100644
index 000000000000..6862bb5f9688
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/tailcalls.c
@@ -0,0 +1,210 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <test_progs.h>
+
+static void test_tailcall_1(void)
+{
+ int err, map_fd, prog_fd, main_fd, i, j;
+ struct bpf_map *prog_array;
+ struct bpf_program *prog;
+ struct bpf_object *obj;
+ __u32 retval, duration;
+ char prog_name[32];
+ char buff[128] = {};
+
+ err = bpf_prog_load("tailcall1.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;
+
+ /* Testing 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;
+ }
+
+ for (i = 0; i < bpf_map__def(prog_array)->max_entries; i++) {
+ err = bpf_prog_test_run(main_fd, 1, buff, sizeof(buff), 0,
+ &duration, &retval, NULL);
+ CHECK(err || retval != i, "tailcall",
+ "err %d errno %d retval %d\n", err, errno, retval);
+
+ err = bpf_map_delete_elem(map_fd, &i);
+ if (CHECK_FAIL(err))
+ goto out;
+ }
+
+ /* Testing JMP -> NOP */
+ err = bpf_prog_test_run(main_fd, 1, buff, sizeof(buff), 0,
+ &duration, &retval, NULL);
+ CHECK(err || retval != 3, "tailcall", "err %d errno %d retval %d\n",
+ err, errno, retval);
+
+ /* Testing JMP -> 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, buff, sizeof(buff), 0,
+ &duration, &retval, NULL);
+ CHECK(err || retval != 0, "tailcall", "err %d errno %d retval %d\n",
+ err, errno, retval);
+
+ for (i = 0; i < bpf_map__def(prog_array)->max_entries; i++) {
+ j = bpf_map__def(prog_array)->max_entries - 1 - i;
+ snprintf(prog_name, sizeof(prog_name), "classifier/%i", j);
+
+ 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;
+ }
+
+ for (i = 0; i < bpf_map__def(prog_array)->max_entries; i++) {
+ j = bpf_map__def(prog_array)->max_entries - 1 - i;
+
+ err = bpf_prog_test_run(main_fd, 1, buff, sizeof(buff), 0,
+ &duration, &retval, NULL);
+ CHECK(err || retval != j, "tailcall",
+ "err %d errno %d retval %d\n", err, errno, retval);
+
+ err = bpf_map_delete_elem(map_fd, &i);
+ if (CHECK_FAIL(err))
+ goto out;
+ }
+
+ err = bpf_prog_test_run(main_fd, 1, buff, sizeof(buff), 0,
+ &duration, &retval, NULL);
+ CHECK(err || retval != 3, "tailcall", "err %d errno %d retval %d\n",
+ err, errno, retval);
+out:
+ bpf_object__close(obj);
+}
+
+static void test_tailcall_2(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];
+ char buff[128] = {};
+
+ err = bpf_prog_load("tailcall2.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;
+
+ 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, buff, sizeof(buff), 0,
+ &duration, &retval, NULL);
+ CHECK(err || retval != 2, "tailcall", "err %d errno %d retval %d\n",
+ err, errno, retval);
+
+ /* Testing JMP -> NOP in entry() and bpf_func_1() */
+ i = 2;
+ err = bpf_map_delete_elem(map_fd, &i);
+ if (CHECK_FAIL(err))
+ goto out;
+
+ err = bpf_prog_test_run(main_fd, 1, buff, sizeof(buff), 0,
+ &duration, &retval, NULL);
+ CHECK(err || retval != 1, "tailcall", "err %d errno %d retval %d\n",
+ err, errno, retval);
+
+ i = 0;
+ err = bpf_map_delete_elem(map_fd, &i);
+ if (CHECK_FAIL(err))
+ goto out;
+
+ /* Tail call limit */
+ err = bpf_prog_test_run(main_fd, 1, buff, sizeof(buff), 0,
+ &duration, &retval, NULL);
+ CHECK(err || retval != 3, "tailcall", "err %d errno %d retval %d\n",
+ err, errno, retval);
+out:
+ bpf_object__close(obj);
+}
+
+void test_tailcalls(void)
+{
+ test_tailcall_1();
+ test_tailcall_2();
+}
diff --git a/tools/testing/selftests/bpf/progs/tailcall1.c b/tools/testing/selftests/bpf/progs/tailcall1.c
new file mode 100644
index 000000000000..63531e1a9fa4
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/tailcall1.c
@@ -0,0 +1,48 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/bpf.h>
+
+#include "bpf_helpers.h"
+
+struct {
+ __uint(type, BPF_MAP_TYPE_PROG_ARRAY);
+ __uint(max_entries, 3);
+ __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)
+TAIL_FUNC(2)
+
+SEC("classifier")
+int entry(struct __sk_buff *skb)
+{
+ /* Multiple locations to make sure we patch
+ * all of them.
+ */
+ bpf_tail_call(skb, &jmp_table, 0);
+ bpf_tail_call(skb, &jmp_table, 0);
+ bpf_tail_call(skb, &jmp_table, 0);
+ bpf_tail_call(skb, &jmp_table, 0);
+
+ bpf_tail_call(skb, &jmp_table, 1);
+ bpf_tail_call(skb, &jmp_table, 1);
+ bpf_tail_call(skb, &jmp_table, 1);
+ bpf_tail_call(skb, &jmp_table, 1);
+
+ bpf_tail_call(skb, &jmp_table, 2);
+ bpf_tail_call(skb, &jmp_table, 2);
+ bpf_tail_call(skb, &jmp_table, 2);
+ bpf_tail_call(skb, &jmp_table, 2);
+
+ return 3;
+}
+
+char __license[] SEC("license") = "GPL";
+int _version SEC("version") = 1;
diff --git a/tools/testing/selftests/bpf/progs/tailcall2.c b/tools/testing/selftests/bpf/progs/tailcall2.c
new file mode 100644
index 000000000000..21c85c477210
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/tailcall2.c
@@ -0,0 +1,59 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/bpf.h>
+
+#include "bpf_helpers.h"
+
+struct {
+ __uint(type, BPF_MAP_TYPE_PROG_ARRAY);
+ __uint(max_entries, 5);
+ __uint(key_size, sizeof(__u32));
+ __uint(value_size, sizeof(__u32));
+} jmp_table SEC(".maps");
+
+SEC("classifier/0")
+int bpf_func_0(struct __sk_buff *skb)
+{
+ bpf_tail_call(skb, &jmp_table, 1);
+ return 0;
+}
+
+SEC("classifier/1")
+int bpf_func_1(struct __sk_buff *skb)
+{
+ bpf_tail_call(skb, &jmp_table, 2);
+ return 1;
+}
+
+SEC("classifier/2")
+int bpf_func_2(struct __sk_buff *skb)
+{
+ return 2;
+}
+
+SEC("classifier/3")
+int bpf_func_3(struct __sk_buff *skb)
+{
+ bpf_tail_call(skb, &jmp_table, 4);
+ return 3;
+}
+
+SEC("classifier/4")
+int bpf_func_4(struct __sk_buff *skb)
+{
+ bpf_tail_call(skb, &jmp_table, 3);
+ return 4;
+}
+
+SEC("classifier")
+int entry(struct __sk_buff *skb)
+{
+ bpf_tail_call(skb, &jmp_table, 0);
+ /* Check multi-prog update. */
+ bpf_tail_call(skb, &jmp_table, 2);
+ /* Check tail call limit. */
+ bpf_tail_call(skb, &jmp_table, 3);
+ return 3;
+}
+
+char __license[] SEC("license") = "GPL";
+int _version SEC("version") = 1;
--
2.21.0
