Re: [PATCH v5 1/3] Provide in-kernel headers to make extending kernel easier - Greg Kroah-Hartman

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Karim Yaghmour <karim.yaghmour@opersys.com>,
	Joel Fernandes <joel@joelfernandes.org>,
	Kees Cook <keescook@chromium.org>,
	Olof Johansson <olof@lixom.net>,
	Alexei Starovoitov <alexei.starovoitov@gmail.com>,
	Joel Fernandes <joelaf@google.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Qais Yousef <qais.yousef@arm.com>,
	Dietmar Eggemann <dietmar.eggemann@arm.com>,
	Manoj Rao <linux@manojrajarao.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Alexei Starovoitov <ast@kernel.org>,
	atish patra <atishp04@gmail.com>,
	Daniel Colascione <dancol@google.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Guenter Roeck <groeck@chromium.org>,
	Jonathan Corbet <corbet@lwn.net>,
	Android Kernel Team <kernel-team@android.com>,
	"open list:DOCUMENTATION" <linux-doc@vger.kernel.org>,
	"open list:KERNEL SELFTEST FRAMEWORK" 
	<linux-kselftest@vger.kernel.org>,
	linux-trace-devel@vger.kernel.org,
	Masahiro Yamada <yamada.masahiro@socionext.com>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	Randy Dunlap <rdunlap@infradead.org>,
	Shuah Khan <shuah@kernel.org>, Yonghong Song <yhs@fb.com>
Subject: Re: [PATCH v5 1/3] Provide in-kernel headers to make extending kernel easier
Date: Tue, 16 Apr 2019 16:22:40 +0200	[thread overview]
Message-ID: <20190416142240.GA31920@kroah.com> (raw)
In-Reply-To: <20190416094509.1af6326b@gandalf.local.home>

On Tue, Apr 16, 2019 at 09:45:09AM -0400, Steven Rostedt wrote:
> On Tue, 16 Apr 2019 09:32:37 -0400
> Karim Yaghmour <karim.yaghmour@opersys.com> wrote:
> 
> > >>> Then we should perhaps make a new file system call tarballs ;-)
> > >>>
> > >>>   /sys/kernel/tarballs/
> > >>>
> > >>> and place everything there. That way it removes it from /proc (which is
> > >>> the worse place for that) and also makes it something other than debug.
> > >>> That's what I did for tracefs.  
> > >>
> > >> As horrible as that suggestion is, it does kind of make sense :)
> > >>
> > >> We can't put this in debugfs as that's only for debugging and systems
> > >> should never have that mounted for normal operations (users want to
> > >> build ebpf programs), and /proc really should be for processes but that
> > >> horse is long left the barn.
> > >>
> > >> But, I'm willing to consider putting this either in a system-fs-like
> > >> filesystem, or just in sysfs itself, we do have /sys/kernel/ to play
> > >> around in if the main objection is that we should not be cluttering up
> > >> /proc with stuff like this.
> > >>  
> > > 
> > > I am ok with the suggestion of /sys/kernel for the archive. That also seems
> > > to fit well with the idea that the headers are kernel related and probably
> > > belong here more strictly speaking, than /proc.  
> > 
> > This makes sense. And if it alleviates concerns regarding extending 
> > /proc ABIs then might as well switch to this.
> > 
> > Olof, what do you think of this?
> 
> BTW, the name "tarballs" was kind of a joke. Probably should come up
> with a better name. Although, I'm fine with tarballsfs ;-)

No need to have this be a separate filesystem, we can use a binary sysfs
file in /sys/kernel/ for this as the kernel is not doing any "parsing"
of the data, it is just dumping it out to userspace.

If I make /sys/kernel/config.gz be the same thing as /proc/config.gz
will you fix up 'make localmodconfig' to use it?  :)

thanks,

greg k-h