linux-kernel - Re: [PATCH bpf-next v3 2/6] bpf/libbpf: BTF support for typed ksyms

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Message-ID: <CAEf4BzbTWGQ4QAOz29Jzj14RwprhsuDSbudU+rrUTaOg9ZP9Zg@mail.gmail.com>
Date:   Mon, 21 Sep 2020 10:52:41 -0700
From:   Andrii Nakryiko <andrii.nakryiko@...il.com>
To:     Hao Luo <haoluo@...gle.com>
Cc:     Networking <netdev@...r.kernel.org>, bpf <bpf@...r.kernel.org>,
        open list <linux-kernel@...r.kernel.org>,
        "open list:KERNEL SELFTEST FRAMEWORK" 
        <linux-kselftest@...r.kernel.org>, Shuah Khan <shuah@...nel.org>,
        Alexei Starovoitov <ast@...nel.org>,
        Andrii Nakryiko <andriin@...com>,
        Daniel Borkmann <daniel@...earbox.net>,
        Martin KaFai Lau <kafai@...com>,
        Song Liu <songliubraving@...com>, Yonghong Song <yhs@...com>,
        John Fastabend <john.fastabend@...il.com>,
        KP Singh <kpsingh@...omium.org>,
        Quentin Monnet <quentin@...valent.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        Ingo Molnar <mingo@...hat.com>
Subject: Re: [PATCH bpf-next v3 2/6] bpf/libbpf: BTF support for typed ksyms

On Wed, Sep 16, 2020 at 3:38 PM Hao Luo <haoluo@...gle.com> wrote:
>
> If a ksym is defined with a type, libbpf will try to find the ksym's btf
> information from kernel btf. If a valid btf entry for the ksym is found,
> libbpf can pass in the found btf id to the verifier, which validates the
> ksym's type and value.
>
> Typeless ksyms (i.e. those defined as 'void') will not have such btf_id,
> but it has the symbol's address (read from kallsyms) and its value is
> treated as a raw pointer.
>
> Signed-off-by: Hao Luo <haoluo@...gle.com>
> ---

This looks nice and clean, thanks!

Acked-by: Andrii Nakryiko <andriin@...com>

>  tools/lib/bpf/libbpf.c | 112 ++++++++++++++++++++++++++++++++++++-----
>  1 file changed, 99 insertions(+), 13 deletions(-)
>

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