From: Andrii Nakryiko <andrii.nakryiko@gmail.com>
To: "Mauricio Vásquez" <mauricio@kinvolk.io>
Cc: Networking <netdev@vger.kernel.org>, bpf <bpf@vger.kernel.org>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>,
Quentin Monnet <quentin@isovalent.com>,
Rafael David Tinoco <rafaeldtinoco@gmail.com>,
Lorenzo Fontana <lorenzo.fontana@elastic.co>,
Leonardo Di Donato <leonardo.didonato@elastic.co>
Subject: Re: [PATCH bpf-next v7 5/7] bpftool: Implement btfgen_get_btf()
Date: Wed, 16 Feb 2022 10:20:37 -0800 [thread overview]
Message-ID: <CAEf4BzakR4cbe7aT09y5tnGebrixj8RnZsg13G+VLqpgQoWa7Q@mail.gmail.com> (raw)
In-Reply-To: <20220215225856.671072-6-mauricio@kinvolk.io>
On Tue, Feb 15, 2022 at 2:59 PM Mauricio Vásquez <mauricio@kinvolk.io> wrote:
>
> The last part of the BTFGen algorithm is to create a new BTF object with
> all the types that were recorded in the previous steps.
>
> This function performs two different steps:
> 1. Add the types to the new BTF object by using btf__add_type(). Some
> special logic around struct and unions is implemented to only add the
> members that are really used in the field-based relocations. The type
> ID on the new and old BTF objects is stored on a map.
> 2. Fix all the type IDs on the new BTF object by using the IDs saved in
> the previous step.
>
> Signed-off-by: Mauricio Vásquez <mauricio@kinvolk.io>
> Signed-off-by: Rafael David Tinoco <rafael.tinoco@aquasec.com>
> Signed-off-by: Lorenzo Fontana <lorenzo.fontana@elastic.co>
> Signed-off-by: Leonardo Di Donato <leonardo.didonato@elastic.co>
> ---
> tools/bpf/bpftool/gen.c | 100 +++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 99 insertions(+), 1 deletion(-)
>
[...]
> + cloned_m = btf_members(cloned_type);
> + m = btf_members(type);
> + vlen = btf_vlen(cloned_type);
> + for (idx_src = 0; idx_src < vlen; idx_src++, cloned_m++, m++) {
> + /* add only members that are marked as used */
> + if (cloned_m->name_off != MARKED)
> + continue;
> +
> + name = btf__str_by_offset(info->src_btf, m->name_off);
> + err = btf__add_field(btf_new, name, m->type,
> + BTF_MEMBER_BIT_OFFSET(m->offset),
> + BTF_MEMBER_BITFIELD_SIZE(m->offset));
BTF_MEMBER_BIT_OFFSET() and BTF_MEMBER_BIT_OFFSET() shouldn't be used
unconditionally, only if kflag is set. It's better to use
btf_member_bit_offset() and btf_member_bitfield_size() helpers here,
they handle this transparently.
> + if (err < 0)
> + goto err_out;
> + }
> + } else {
> + err = btf__add_type(btf_new, info->src_btf, type);
> + if (err < 0)
> + goto err_out;
> + new_id = err;
> + }
> +
> + /* add ID mapping */
> + ids[i] = new_id;
> + }
> +
[...]
next prev parent reply other threads:[~2022-02-16 18:20 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-15 22:58 [PATCH bpf-next v7 0/7] libbpf: Implement BTFGen Mauricio Vásquez
2022-02-15 22:58 ` [PATCH bpf-next v7 1/7] libbpf: split bpf_core_apply_relo() Mauricio Vásquez
2022-02-16 1:52 ` Alexei Starovoitov
2022-02-15 22:58 ` [PATCH bpf-next v7 2/7] libbpf: Expose bpf_core_{add,free}_cands() to bpftool Mauricio Vásquez
2022-02-15 22:58 ` [PATCH bpf-next v7 3/7] bpftool: Add gen min_core_btf command Mauricio Vásquez
2022-02-15 22:58 ` [PATCH bpf-next v7 4/7] bpftool: Implement "gen min_core_btf" logic Mauricio Vásquez
2022-02-18 16:20 ` Quentin Monnet
2022-02-18 19:43 ` Mauricio Vásquez Bernal
2022-02-18 19:48 ` Andrii Nakryiko
2022-02-18 19:52 ` Quentin Monnet
2022-02-15 22:58 ` [PATCH bpf-next v7 5/7] bpftool: Implement btfgen_get_btf() Mauricio Vásquez
2022-02-16 18:20 ` Andrii Nakryiko [this message]
2022-02-15 22:58 ` [PATCH bpf-next v7 6/7] bpftool: gen min_core_btf explanation and examples Mauricio Vásquez
2022-02-16 18:20 ` Andrii Nakryiko
2022-02-15 22:58 ` [PATCH bpf-next v7 7/7] selftests/bpf: Test "bpftool gen min_core_btf" Mauricio Vásquez
2022-02-16 18:20 ` Andrii Nakryiko
2022-02-16 18:20 ` [PATCH bpf-next v7 0/7] libbpf: Implement BTFGen Andrii Nakryiko
2022-02-17 22:07 ` Mauricio Vásquez Bernal
2022-02-17 22:12 ` Andrii Nakryiko
2022-02-16 18:30 ` patchwork-bot+netdevbpf
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=CAEf4BzakR4cbe7aT09y5tnGebrixj8RnZsg13G+VLqpgQoWa7Q@mail.gmail.com \
--to=andrii.nakryiko@gmail.com \
--cc=andrii@kernel.org \
--cc=ast@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=daniel@iogearbox.net \
--cc=leonardo.didonato@elastic.co \
--cc=lorenzo.fontana@elastic.co \
--cc=mauricio@kinvolk.io \
--cc=netdev@vger.kernel.org \
--cc=quentin@isovalent.com \
--cc=rafaeldtinoco@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).