[PATCH v2 bpf-next 07/18] selftests/bpf: BTF distill tests to ensure LOC[_PARAM|_PROTO] add to split BTF
From: Alan Maguire <hidden>
Date: 2026-09-01 16:58:55
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, Shuah Khan, Linus Torvalds
When creating distilled BTF, BTF_KIND_FUNC, _LOC_PARAM and _LOC_PROTO should be added to split BTF. This means potentially some duplication of location information, but only for out-of-tree modules that use distilled base/split BTF. Signed-off-by: Alan Maguire <redacted> --- .../selftests/bpf/prog_tests/btf_distill.c | 76 +++++++++++++++++++ 1 file changed, 76 insertions(+)
diff --git a/tools/testing/selftests/bpf/prog_tests/btf_distill.c b/tools/testing/selftests/bpf/prog_tests/btf_distill.c
index fb67ae195a73..f433b29ffce9 100644
--- a/tools/testing/selftests/bpf/prog_tests/btf_distill.c
+++ b/tools/testing/selftests/bpf/prog_tests/btf_distill.c@@ -671,6 +671,80 @@ static void test_distilled_base_embedded_err(void) btf__free(btf1); } +/* LOC_PARAM, LOC_PROTO should be added to split BTF. */ +static void test_distilled_loc(void) +{ + struct btf *btf1 = NULL, *btf2 = NULL, *btf3 = NULL, *btf4 = NULL; + + btf1 = btf__new_empty(); + if (!ASSERT_OK_PTR(btf1, "empty_main_btf")) + return; + + btf__add_int(btf1, "int", 4, BTF_INT_SIGNED); /* [1] int */ + btf__add_func_proto(btf1, 1); /* [2] int (*)(int); */ + btf__add_func_param(btf1, "p1", 1); + btf__add_func(btf1, "foo", BTF_FUNC_STATIC, 2); /* [3] int foo(int); */ + btf__add_loc_param(btf1, 4, BTF_LOC_PARAM_SIGNED | BTF_LOC_PARAM_CONST); + btf__add_loc_param_value(btf1, -1); /* [4] loc value */ + + VALIDATE_RAW_BTF( + btf1, + "[1] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED", + "[2] FUNC_PROTO '(anon)' ret_type_id=1 vlen=1\n" + "\t'p1' type_id=1", + "[3] FUNC 'foo' type_id=2 linkage=static", + "[4] LOC_PARAM '(anon)' size=4 flags=0x3 vlen=1\n" + "\tvalue=-1"); + + btf2 = btf__new_empty_split(btf1); + if (!ASSERT_OK_PTR(btf2, "empty_split_btf")) + goto cleanup; + + btf__add_loc_proto(btf2); /* [5] loc proto */ + btf__add_loc_proto_param(btf2, 4); /* param value */ + + btf__add_locsec(btf2, ".locs"); /* [6] locsec */ + btf__add_locsec_loc(btf2, 3, 5, 256); /* "foo" offset 256 */ + VALIDATE_RAW_BTF( + btf2, + "[1] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED", + "[2] FUNC_PROTO '(anon)' ret_type_id=1 vlen=1\n" + "\t'p1' type_id=1", + "[3] FUNC 'foo' type_id=2 linkage=static", + "[4] LOC_PARAM '(anon)' size=4 flags=0x3 vlen=1\n" + "\tvalue=-1", + "[5] LOC_PROTO '(anon)' vlen=1\n" + "\ttype_id=4", + "[6] LOCSEC '.locs' vlen=1\n" + "\tfunc_type_id=3 loc_proto_type_id=5 offset=256"); + + if (!ASSERT_EQ(0, btf__distill_base(btf2, &btf3, &btf4), + "distilled_base") || + !ASSERT_OK_PTR(btf3, "distilled_base") || + !ASSERT_OK_PTR(btf4, "distilled_split") || + !ASSERT_EQ(2, btf__type_cnt(btf3), "distilled_base_type_cnt")) + goto cleanup; + + VALIDATE_RAW_BTF( + btf4, + "[1] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED", + /* remainder is split BTF */ + "[2] LOC_PROTO '(anon)' vlen=1\n" + "\ttype_id=6", + "[3] LOCSEC '.locs' vlen=1\n" + "\tfunc_type_id=5 loc_proto_type_id=2 offset=256", + "[4] FUNC_PROTO '(anon)' ret_type_id=1 vlen=1\n" + "\t'p1' type_id=1", + "[5] FUNC 'foo' type_id=4 linkage=static", + "[6] LOC_PARAM '(anon)' size=4 flags=0x3 vlen=1\n" + "\tvalue=-1"); +cleanup: + btf__free(btf4); + btf__free(btf3); + btf__free(btf2); + btf__free(btf1); +} + void test_btf_distill(void) { if (test__start_subtest("distilled_base"))
@@ -689,4 +763,6 @@ void test_btf_distill(void) test_distilled_base_vmlinux(); if (test__start_subtest("distilled_endianness")) test_distilled_endianness(); + if (test__start_subtest("distilled_loc")) + test_distilled_loc(); }
--
2.43.5