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[93.72.16.93]) by smtp.gmail.com with ESMTPSA id e5-20020adfef05000000b00225307f43fbsm10666822wro.44.2022.11.08.07.32.01 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 08 Nov 2022 07:32:02 -0800 (PST) From: Eduard Zingerman To: bpf@vger.kernel.org, ast@kernel.org Cc: andrii@kernel.org, daniel@iogearbox.net, kernel-team@fb.com, yhs@fb.com, Eduard Zingerman Subject: [PATCH bpf-next v2 3/3] selftests/bpf: Tests for BTF_KIND_DECL_TAG dump in C format Date: Tue, 8 Nov 2022 17:31:35 +0200 Message-Id: <20221108153135.491383-4-eddyz87@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20221108153135.491383-1-eddyz87@gmail.com> References: <20221108153135.491383-1-eddyz87@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Covers the following cases: - `__atribute__((btf_decl_tag("...")))` could be applied to structs and unions; - decl tag applied to an empty struct is printed on a single line; - decl tags with the same name could be applied to several structs; - several decl tags could be applied to the same struct; - attribute `packed` works fine with decl tags (it is a separate branch in `tools/lib/bpf/btf_dump.c:btf_dump_emit_attributes`; - decl tag could be attached to typedef; - decl tag could be attached to a struct field; - decl tag could be attached to a struct field and a struct itself simultaneously; - decl tag could be attached to a global variable; - decl tag could be attached to a func proto parameter; - btf__add_decl_tag could be interleaved with btf_dump__dump_type calls. Signed-off-by: Eduard Zingerman --- .../selftests/bpf/prog_tests/btf_dump.c | 80 +++++++++++++++++++ .../bpf/progs/btf_dump_test_case_decl_tag.c | 65 +++++++++++++++ 2 files changed, 145 insertions(+) create mode 100644 tools/testing/selftests/bpf/progs/btf_dump_test_case_decl_tag.c diff --git a/tools/testing/selftests/bpf/prog_tests/btf_dump.c b/tools/testing/selftests/bpf/prog_tests/btf_dump.c index a0bdfc45660d..0d428c559ad9 100644 --- a/tools/testing/selftests/bpf/prog_tests/btf_dump.c +++ b/tools/testing/selftests/bpf/prog_tests/btf_dump.c @@ -23,6 +23,7 @@ static struct btf_dump_test_case { {"btf_dump: bitfields", "btf_dump_test_case_bitfields", true}, {"btf_dump: multidim", "btf_dump_test_case_multidim", false}, {"btf_dump: namespacing", "btf_dump_test_case_namespacing", false}, + {"btf_dump: decl_tag", "btf_dump_test_case_decl_tag", true}, }; static int btf_dump_all_types(const struct btf *btf, struct btf_dump *d) @@ -345,6 +346,82 @@ static void test_btf_dump_incremental(void) btf__free(btf); } +static void test_btf_dump_func_proto_decl_tag(void) +{ + struct btf *btf = NULL; + struct btf_dump *d = NULL; + int id, err; + + dump_buf_file = open_memstream(&dump_buf, &dump_buf_sz); + if (!ASSERT_OK_PTR(dump_buf_file, "dump_memstream")) + return; + btf = btf__new_empty(); + if (!ASSERT_OK_PTR(btf, "new_empty")) + goto err_out; + d = btf_dump__new(btf, btf_dump_printf, dump_buf_file, NULL); + if (!ASSERT_OK(libbpf_get_error(d), "btf_dump__new")) + goto err_out; + + /* First, BTF corresponding to the following C code: + * + * typedef void (*fn)(int a __btf_decl_tag("a_tag")); + * + */ + id = btf__add_int(btf, "int", 4, BTF_INT_SIGNED); + ASSERT_EQ(id, 1, "int_id"); + id = btf__add_func_proto(btf, 0); + ASSERT_EQ(id, 2, "func_proto_id"); + err = btf__add_func_param(btf, "a", 1); + ASSERT_OK(err, "func_param_ok"); + id = btf__add_decl_tag(btf, "a_tag", 2, 0); + ASSERT_EQ(id, 3, "decl_tag_a"); + id = btf__add_ptr(btf, 2); + ASSERT_EQ(id, 4, "proto_ptr"); + id = btf__add_typedef(btf, "fn", 4); + ASSERT_EQ(id, 5, "typedef"); + + err = btf_dump_all_types(btf, d); + ASSERT_OK(err, "btf_dump_all_types #1"); + fflush(dump_buf_file); + dump_buf[dump_buf_sz] = 0; /* some libc implementations don't do this */ + + ASSERT_STREQ(dump_buf, + "#if __has_attribute(btf_decl_tag)\n" + "#define __btf_decl_tag(x) __attribute__((btf_decl_tag(x)))\n" + "#else\n" + "#define __btf_decl_tag(x)\n" + "#endif\n" + "\n" + "typedef void (*fn)(int a __btf_decl_tag(\"a_tag\"));\n\n", + "decl tags for fn"); + + /* Next, add BTF corresponding to the following C code: + * + * typedef int foo __btf_decl_tag("foo_tag"); + * + * To verify that decl_tag's table is updated incrementally. + */ + id = btf__add_typedef(btf, "foo", 1); + ASSERT_EQ(id, 6, "typedef"); + id = btf__add_decl_tag(btf, "foo_tag", 6, -1); + ASSERT_EQ(id, 7, "decl_tag_foo"); + + fseek(dump_buf_file, 0, SEEK_SET); + err = btf_dump_all_types(btf, d); + ASSERT_OK(err, "btf_dump_all_types #2"); + fflush(dump_buf_file); + dump_buf[dump_buf_sz] = 0; /* some libc implementations don't do this */ + + ASSERT_STREQ(dump_buf, + "typedef int foo __btf_decl_tag(\"foo_tag\");\n\n", + "decl tags for foo"); +err_out: + fclose(dump_buf_file); + free(dump_buf); + btf_dump__free(d); + btf__free(btf); +} + #define STRSIZE 4096 static void btf_dump_snprintf(void *ctx, const char *fmt, va_list args) @@ -964,6 +1041,9 @@ void test_btf_dump() { if (test__start_subtest("btf_dump: incremental")) test_btf_dump_incremental(); + if (test__start_subtest("btf_dump: func arg decl_tag")) + test_btf_dump_func_proto_decl_tag(); + btf = libbpf_find_kernel_btf(); if (!ASSERT_OK_PTR(btf, "no kernel BTF found")) return; diff --git a/tools/testing/selftests/bpf/progs/btf_dump_test_case_decl_tag.c b/tools/testing/selftests/bpf/progs/btf_dump_test_case_decl_tag.c new file mode 100644 index 000000000000..1205351e9a68 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/btf_dump_test_case_decl_tag.c @@ -0,0 +1,65 @@ +// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) + +/* + * BTF-to-C dumper test for __atribute__((btf_decl_tag("..."))). + */ + +#define SEC(x) __attribute__((section(x))) + +/* ----- START-EXPECTED-OUTPUT ----- */ +#if __has_attribute(btf_decl_tag) +#define __btf_decl_tag(x) __attribute__((btf_decl_tag(x))) +#else +#define __btf_decl_tag(x) +#endif + +struct empty_with_tag {} __btf_decl_tag("a"); + +struct one_tag { + int x; +} __btf_decl_tag("b"); + +struct same_tag { + int x; +} __btf_decl_tag("b"); + +struct two_tags { + int x; +} __btf_decl_tag("a") __btf_decl_tag("b"); + +struct packed { + int x; + short y; +} __attribute__((packed)) __btf_decl_tag("another_name"); + +typedef int td_with_tag __btf_decl_tag("td"); + +struct tags_on_fields { + int x __btf_decl_tag("t1"); + int y; + int z __btf_decl_tag("t2") __btf_decl_tag("t3"); +}; + +struct tag_on_field_and_struct { + int x __btf_decl_tag("t1"); +} __btf_decl_tag("t2"); + +struct root_struct { + struct empty_with_tag a; + struct one_tag b; + struct same_tag c; + struct two_tags d; + struct packed e; + td_with_tag f; + struct tags_on_fields g; + struct tag_on_field_and_struct h; +}; + +SEC(".data") int global_var __btf_decl_tag("var_tag") = (int)777; + +/* ------ END-EXPECTED-OUTPUT ------ */ + +int f(struct root_struct *s) +{ + return 0; +}