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Message-ID: <63177c72b94a653707d6b984ca789ecf8ebf0a95.camel@russell.cc>
Subject: Re: [RFC PATCH v1 3/6] powerpc: Add skeleton for Kernel Userspace
 Execution Prevention
From:   Russell Currey <ruscur@russell.cc>
To:     Christophe Leroy <christophe.leroy@c-s.fr>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>,
        Michael Ellerman <mpe@ellerman.id.au>
Cc:     linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Date:   Mon, 19 Nov 2018 13:44:08 +1100
In-Reply-To: <1b27e980fa8dda09955b35be09c99bb1e22fef70.1541568127.git.christophe.leroy@c-s.fr>
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         <1b27e980fa8dda09955b35be09c99bb1e22fef70.1541568127.git.christophe.leroy@c-s.fr>
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On Wed, 2018-11-07 at 16:56 +0000, Christophe Leroy wrote:
> This patch adds a skeleton for Kernel Userspace Execution Prevention.
> 
> Then subarches implementing it have to define CONFIG_PPC_HAVE_KUEP
> and provide setup_kuep() function.
> 
> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>

An open question (with nothing to do specifically with this patch):

For what reason would you ever disable execution prevention?  Clearly
there must be something since "nosmep" is a thing, but I don't know why
we'd ever do it.

- Russell