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Date:   Thu, 14 Feb 2019 22:47:20 -0500
From:   Joel Fernandes <joel@joelfernandes.org>
To:     Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc:     netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        Andrew Morton <akpm@linux-foundation.org>, ast@kernel.org,
        atishp04@gmail.com, dancol@google.com,
        Dan Williams <dan.j.williams@intel.com>,
        gregkh@linuxfoundation.org, Jonathan Corbet <corbet@lwn.net>,
        karim.yaghmour@opersys.com, Kees Cook <keescook@chromium.org>,
        kernel-team@android.com, linux-doc@vger.kernel.org,
        linux-kselftest@vger.kernel.org,
        Manoj Rao <linux@manojrajarao.com>,
        Masahiro Yamada <yamada.masahiro@socionext.com>,
        paulmck@linux.vnet.ibm.com,
        "Peter Zijlstra (Intel)" <peterz@infradead.org>,
        rdunlap@infradead.org, rostedt@goodmis.org,
        Shuah Khan <shuah@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>, yhs@fb.com
Subject: Re: [PATCH v2 1/2] Provide in-kernel headers for making it easy to
 extend the kernel
Message-ID: <20190215034720.GA230433@google.com>
References: <20190211143600.15021-1-joel@joelfernandes.org>
 <20190215031926.ljzluy2cfxp64u6o@ast-mbp>
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On Thu, Feb 14, 2019 at 07:19:29PM -0800, Alexei Starovoitov wrote:
> On Mon, Feb 11, 2019 at 09:35:59AM -0500, Joel Fernandes (Google) wrote:
> > Introduce in-kernel headers and other artifacts which are made available
> > as an archive through proc (/proc/kheaders.txz file). This archive makes
> > it possible to build kernel modules, run eBPF programs, and other
> > tracing programs that need to extend the kernel for tracing purposes
> > without any dependency on the file system having headers and build
> > artifacts.
> > 
> > On Android and embedded systems, it is common to switch kernels but not
> > have kernel headers available on the file system. Raw kernel headers
> > also cannot be copied into the filesystem like they can be on other
> > distros, due to licensing and other issues. There's no linux-headers
> > package on Android. Further once a different kernel is booted, any
> > headers stored on the file system will no longer be useful. By storing
> > the headers as a compressed archive within the kernel, we can avoid these
> > issues that have been a hindrance for a long time.
> 
> The set looks good to me and since the main use case is building bpf progs
> I can route it via bpf-next tree if there are no objections.
> Masahiro, could you please ack it?
> 

Yes, eBPF is one of the usecases. After this, I am also planning to send
patches to BCC so that it can use this feature when compiling C to eBPF.

Thanks!

 - Joel