From: Eduard Zingerman <eddyz87@gmail.com>
To: Alan Maguire <alan.maguire@oracle.com>,
ast@kernel.org, andrii@kernel.org, jolsa@kernel.org
Cc: daniel@iogearbox.net, ihor.solodrai@linux.dev,
yonghong.song@linux.dev, song@kernel.org, qmo@kernel.org,
martin.lau@linux.dev, memxor@gmail.com, emil@etsalapatis.com,
bpf@vger.kernel.org, nsc@kernel.org, puranjay@kernel.org,
yatsenko@meta.com
Subject: Re: [PATCH v3 bpf-next 06/11] selftests/bpf: BTF distill tests to ensure LOC[_PARAM|_PROTO] add to split BTF
Date: Fri, 18 Sep 2026 12:59:04 -0700 [thread overview]
Message-ID: <fc7dd9b68e50a07af40f6ac571fb7adb6ba512d3.camel@gmail.com> (raw)
In-Reply-To: <20260916074118.1007116-7-alan.maguire@oracle.com>
On Wed, 2026-09-16 at 08:41 +0100, Alan Maguire wrote:
> 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 <alan.maguire@oracle.com>
> ---
> .../selftests/bpf/prog_tests/btf_distill.c | 101 ++++++++++++++++++
> 1 file changed, 101 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..141a4cb1f405 100644
> --- a/tools/testing/selftests/bpf/prog_tests/btf_distill.c
> +++ b/tools/testing/selftests/bpf/prog_tests/btf_distill.c
> @@ -671,6 +671,105 @@ 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;
> + struct btf *btf4 = NULL, *btf5 = 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 */
> + btf__add_loc_proto(btf1); /* [5] loc proto */
> + btf__add_loc_proto_param(btf1, 4); /* param 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",
> + "[5] LOC_PROTO '(anon)' vlen=1\n"
> + "\ttype_id=4");
Maybe also add an unrelated type to the base, such that effects of the
distill are visible?
> + btf2 = btf__new_empty_split(btf1);
> + if (!ASSERT_OK_PTR(btf2, "empty_split_btf"))
> + goto cleanup;
> +
> + btf__add_locsec(btf2, "inline.text"); /* [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 'inline.text' 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] LOCSEC 'inline.text' vlen=1\n"
> + "\tfunc_type_id=4 loc_proto_type_id=6 offset=256",
> + "[3] FUNC_PROTO '(anon)' ret_type_id=1 vlen=1\n"
> + "\t'p1' type_id=1",
> + "[4] FUNC 'foo' type_id=3 linkage=static",
> + "[5] LOC_PARAM '(anon)' size=4 flags=0x3 vlen=1\n"
> + "\tvalue=-1",
> + "[6] LOC_PROTO '(anon)' vlen=1\n"
> + "\ttype_id=5");
> +
> + btf5 = btf__new_empty();
> + if (!ASSERT_OK_PTR(btf5, "empty_reloc_btf"))
> + goto cleanup;
I'd add another btf__add_<something> here to shift the ides and make
sure that relocate actually did something.
> + btf__add_int(btf5, "int", 4, BTF_INT_SIGNED); /* [1] int */
> +
> + if (!ASSERT_EQ(btf__relocate(btf4, btf5), 0, "relocate_split"))
> + goto cleanup;
> + VALIDATE_RAW_BTF(
> + btf4,
> + "[1] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED",
> + /* remainder is split BTF */
> + "[2] LOCSEC 'inline.text' vlen=1\n"
> + "\tfunc_type_id=4 loc_proto_type_id=6 offset=256",
> + "[3] FUNC_PROTO '(anon)' ret_type_id=1 vlen=1\n"
> + "\t'p1' type_id=1",
> + "[4] FUNC 'foo' type_id=3 linkage=static",
> + "[5] LOC_PARAM '(anon)' size=4 flags=0x3 vlen=1\n"
> + "\tvalue=-1",
> + "[6] LOC_PROTO '(anon)' vlen=1\n"
> + "\ttype_id=5");
> +
> +cleanup:
> + btf__free(btf5);
> + 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 +788,6 @@ 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();
> }
next prev parent reply other threads:[~2026-09-18 19:59 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-16 7:41 [PATCH v3 bpf-next 00/11] Support inline functions in BTF Alan Maguire
2026-09-16 7:41 ` [PATCH v3 bpf-next 01/11] btf: Extend UAPI to support BTF location (inline site) info Alan Maguire
2026-09-16 9:03 ` bot+bpf-ci
2026-09-16 7:41 ` [PATCH v3 bpf-next 02/11] libbpf: Add support for BTF kinds LOC[_PARAM|_PROTO|SEC] Alan Maguire
2026-09-16 7:55 ` sashiko-bot
2026-09-16 9:03 ` bot+bpf-ci
2026-09-16 7:41 ` [PATCH v3 bpf-next 03/11] selftests/bpf: Test helper support for BTF_KIND_LOC[_PARAM|_PROTO|SEC] Alan Maguire
2026-09-16 8:44 ` bot+bpf-ci
2026-09-18 18:34 ` Eduard Zingerman
2026-09-16 7:41 ` [PATCH v3 bpf-next 04/11] selftests/bpf: Add LOC_PARAM, LOC_PROTO, LOCSEC to field iter tests Alan Maguire
2026-09-18 18:43 ` Eduard Zingerman
2026-09-16 7:41 ` [PATCH v3 bpf-next 05/11] selftests/bpf: Add LOC_PARAM, LOC_PROTO, LOCSEC to dedup split tests Alan Maguire
2026-09-18 18:46 ` Eduard Zingerman
2026-09-16 7:41 ` [PATCH v3 bpf-next 06/11] selftests/bpf: BTF distill tests to ensure LOC[_PARAM|_PROTO] add to split BTF Alan Maguire
2026-09-18 19:59 ` Eduard Zingerman [this message]
2026-09-21 18:36 ` Alan Maguire
2026-09-16 7:41 ` [PATCH v3 bpf-next 07/11] bpftool: Handle multi-split BTF by supporting multiple base BTFs Alan Maguire
2026-09-16 7:54 ` sashiko-bot
2026-09-16 9:03 ` bot+bpf-ci
2026-09-16 7:41 ` [PATCH v3 bpf-next 08/11] bpftool: Document support for multi-split BTF Alan Maguire
2026-09-16 7:41 ` [PATCH v3 bpf-next 09/11] bpftool: Add ability to dump LOC_PARAM, LOC_PROTO and LOCSEC Alan Maguire
2026-09-16 7:55 ` sashiko-bot
2026-09-16 9:03 ` bot+bpf-ci
2026-09-16 22:07 ` Jiri Olsa
2026-09-17 8:27 ` Alan Maguire
2026-09-17 22:00 ` Jiri Olsa
2026-09-18 9:19 ` Alan Maguire
2026-09-18 13:01 ` Jiri Olsa
2026-09-17 16:06 ` Quentin Monnet
2026-09-17 17:32 ` Alan Maguire
2026-09-18 7:29 ` Alan Maguire
2026-09-18 20:51 ` Eduard Zingerman
2026-09-21 18:47 ` Alan Maguire
2026-09-21 21:46 ` Eduard Zingerman
2026-09-22 11:59 ` Quentin Monnet
2026-09-23 8:47 ` Alan Maguire
2026-09-16 7:41 ` [PATCH v3 bpf-next 10/11] selftests/bpf: Test bpftool dump of BTF location info Alan Maguire
2026-09-16 7:56 ` sashiko-bot
2026-09-16 9:03 ` bot+bpf-ci
2026-09-16 7:41 ` [PATCH v3 bpf-next 11/11] Documentation/bpf: Describe new location-related BTF kinds Alan Maguire
2026-09-16 8:01 ` sashiko-bot
2026-09-16 9:03 ` bot+bpf-ci
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