Date: Thu, 10 Nov 2016 09:58:34 +0100
From: Borislav Petkov <bp@suse.de>
To: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Cc: Andy Lutomirski <luto@amacapital.net>, Ingo Molnar <mingo@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>, "H. Peter Anvin" <hpa@zytor.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        X86 ML <x86@kernel.org>,
        "linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>,
        Andy Lutomirski <luto@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Brian Gerst <brgerst@gmail.com>, Chen Yucong <slaoub@gmail.com>,
        Chris Metcalf <cmetcalf@mellanox.com>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Fenghua Yu <fenghua.yu@intel.com>, Huang Rui <ray.huang@amd.com>,
        Jiri Slaby <jslaby@suse.cz>, Jonathan Corbet <corbet@lwn.net>,
        "Michael S . Tsirkin" <mst@redhat.com>,
        Paul Gortmaker <paul.gortmaker@windriver.com>,
        Peter Zijlstra <peterz@infradead.org>,
        "Ravi V . Shankar" <ravi.v.shankar@intel.com>,
        Shuah Khan <shuah@kernel.org>, Vlastimil Babka <vbabka@suse.cz>
Subject: Re: [PATCH 1/4] x86/cpufeature: Add User-Mode Instruction Prevention
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On Wed, Nov 09, 2016 at 07:24:43PM -0800, Ricardo Neri wrote:
> I intended this feature to be configurable at build time in case someone
> wants to build a kernel without it; similar to other features such as
> SMAP. Is this not needed? Should Linux be built with this feature always
> enabled?
> 
> This feature could always be disabled via a kernel parameter, though;
> even if Linux is built with it.

It probably is a good idea to have it build-time configurable for the
embedded folks. But you can do a before and after build and look at
the vmlinux size and see how much it has grown. If it is only a couple
of KBs I guess we can drop the config option even but I know there are
people who still care about KBs too...

-- 
Regards/Gruss,
    Boris.

SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
--