Re: [PATCH v3] kheaders: Move from proc to sysfs

From: Masahiro Yamada <yamada.masahiro@socionext.com>
To: "Joel Fernandes (Google)" <joel@joelfernandes.org>
Cc: "Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
	"Steven Rostedt" <rostedt@goodmis.org>,
	"Adrian Ratiu" <adrian.ratiu@collabora.com>,
	"Alexei Starovoitov" <ast@kernel.org>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	"atish patra" <atishp04@gmail.com>,
	bpf@vger.kernel.org, "Brendan Gregg" <bgregg@netflix.com>,
	"Brendan Gregg" <brendan.d.gregg@gmail.com>,
	"Daniel Colascione" <dancol@google.com>,
	"Daniel Borkmann" <daniel@iogearbox.net>,
	"Dan Williams" <dan.j.williams@intel.com>,
	"Dietmar Eggemann" <dietmar.eggemann@arm.com>,
	duyuchao <yuchao.du@unisoc.com>,
	"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
	"Guenter Roeck" <groeck@chromium.org>,
	"Jonathan Corbet" <corbet@lwn.net>,
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	"Cc: Android Kernel" <kernel-team@android.com>,
	"open list:DOCUMENTATION" <linux-doc@vger.kernel.org>,
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	linux-trace-devel@vger.kernel.org,
	"Manjo Raja Rao" <linux@manojrajarao.com>,
	"Masami Hiramatsu" <mhiramat@kernel.org>,
	"Michał Gregorczyk" <michalgr@fb.com>,
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	"Qais Yousef" <qais.yousef@arm.com>,
	"Randy Dunlap" <rdunlap@infradead.org>,
	"Shuah Khan" <shuah@kernel.org>,
	"Srinivas Ramana" <sramana@codeaurora.org>,
	"Tamir Carmeli" <carmeli.tamir@gmail.com>,
	"Yonghong Song" <yhs@fb.com>
Subject: Re: [PATCH v3] kheaders: Move from proc to sysfs
Date: Wed, 8 May 2019 12:43:34 +0900	[thread overview]
Message-ID: <CAK7LNAQesyT-vspoGKdgRqycZfhtJm5Upx2T6ij-yB5i4Nx5nw@mail.gmail.com> (raw)
In-Reply-To: <20190506013456.86061-1-joel@joelfernandes.org>

On Mon, May 6, 2019 at 10:37 AM Joel Fernandes (Google)
<joel@joelfernandes.org> wrote:
>
> The kheaders archive consisting of the kernel headers used for compiling
> bpf programs is in /proc. However there is concern that moving it here
> will make it permanent. Let us move it to /sys/kernel as discussed [1].
>
> [1] https://lore.kernel.org/patchwork/patch/1067310/#1265969
>
> Suggested-by: Steven Rostedt <rostedt@goodmis.org>
> Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
> ---
> This patch applies on top of the previous patch that was applied to the
> driver tree:
> https://lore.kernel.org/patchwork/patch/1067310/
>
> v2->v3: Fixed sysfs file mode nit (Greg).
> v1->v2: Fixed some kconfig nits.
>
>  init/Kconfig                                | 16 ++++-----
>  kernel/Makefile                             |  4 +--
>  kernel/{gen_ikh_data.sh => gen_kheaders.sh} |  2 +-
>  kernel/kheaders.c                           | 40 +++++++++------------
>  4 files changed, 26 insertions(+), 36 deletions(-)
>  rename kernel/{gen_ikh_data.sh => gen_kheaders.sh} (98%)
>
> diff --git a/init/Kconfig b/init/Kconfig
> index 26a364a95b57..c3661991b089 100644
> --- a/init/Kconfig
> +++ b/init/Kconfig
> @@ -579,15 +579,13 @@ config IKCONFIG_PROC
>           This option enables access to the kernel configuration file
>           through /proc/config.gz.
>
> -config IKHEADERS_PROC
> -       tristate "Enable kernel header artifacts through /proc/kheaders.tar.xz"
> -       depends on PROC_FS
> -       help
> -         This option enables access to the kernel header and other artifacts that
> -         are generated during the build process. These can be used to build eBPF
> -         tracing programs, or similar programs.  If you build the headers as a
> -         module, a module called kheaders.ko is built which can be loaded on-demand
> -         to get access to the headers.
> +config IKHEADERS
> +       tristate "Enable kernel headers through /sys/kernel/kheaders.tar.xz"

I suggested "depends on SYSFS" twice, both in v1 and v2.

https://lore.kernel.org/patchwork/patch/1069806/#1266147
https://lore.kernel.org/patchwork/patch/1070005/#1266279

> +       help
> +         This option enables access to the in-kernel headers that are generated during
> +         the build process. These can be used to build eBPF tracing programs,
> +         or similar programs.  If you build the headers as a module, a module called
> +         kheaders.ko is built which can be loaded on-demand to get access to headers.
>
>  config LOG_BUF_SHIFT
>         int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"

-- 
Best Regards
Masahiro Yamada