[PATCH v6 bpf-next 6/6] selftests: bpf: add dummy prog for bpf2bpf with tailcall
From: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Date: 2020-07-31 00:09:05
Also in:
bpf
Subsystem:
bpf [general] (safe dynamic programs and tools), bpf [selftests] (test runners & infrastructure), kernel selftest framework, the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Shuah Khan, Linus Torvalds
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@intel.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