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From: Kees Cook <keescook@chromium.org>
Date: Mon, 13 Jun 2016 13:15:40 -0700
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Subject: Re: [PATCH] gcc-plugins: disable under COMPILE_TEST
To: Sedat Dilek <sedat.dilek@gmail.com>
Cc: Michal Marek <mmarek@suse.com>, Stephen Rothwell <sfr@canb.auug.org.au>,
        Emese Revfy <re.emese@gmail.com>,
        Paul Gortmaker <paul.gortmaker@windriver.com>,
        Sudip Mukherjee <sudipm.mukherjee@gmail.com>,
        Linux-Next <linux-next@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        "kernel-hardening@lists.openwall.com" 
	<kernel-hardening@lists.openwall.com>
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On Mon, Jun 13, 2016 at 1:40 AM, Sedat Dilek <sedat.dilek@gmail.com> wrote:
> On Sat, Jun 11, 2016 at 6:12 PM, Kees Cook <keescook@chromium.org> wrote:
>> Since adding the gcc plugin development headers is required for the
>> gcc plugin support, we should ease into this new kernel build dependency
>> more slowly. For now, disable the gcc plugins under COMPILE_TEST so that
>> all*config builds will skip it.
>>
>
> [ This might be a bit off-topic - Feel free to answer ]
>
> Hi,
>
> I want to try that new "GCC-plugin" feature.
> Do you have a Git repo for "easy-testing"?

Start with linux-next. It has the basic infrastructure. The
"latent_entropy" plugin is in my kssp tree here:
http://git.kernel.org/cgit/linux/kernel/git/kees/linux.git/log/?h=kspp/gcc-plugins/latent_entropy
though it is not the most up to date version.

> Does the kernel's build-system check for installed "gcc-plugin
> development headers"?

Yes, when the plugins have been selected.

> Which GCC versions support "gcc-plugin" feature?

gcc-4.5 and newer.

> I am here on Ubuntu/precise AMD64 and have gcc-4.6.4 and gcc-4.9.2.

I strongly recommend upgrading to Ubuntu 16.04, but regardless, using
gcc 4.9 should be fine.

> [ Optional ]
> What about the topic and support for "LLVM/Clang and hardening" of the
> Linux-kernel?

I haven't been involved in that project, sorry.

-Kees

-- 
Kees Cook
Chrome OS & Brillo Security