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Date:   Thu, 20 Sep 2018 10:00:53 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     Tim Chen <tim.c.chen@linux.intel.com>
Cc:     Jiri Kosina <jikos@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Tom Lendacky <thomas.lendacky@amd.com>,
        Ingo Molnar <mingo@redhat.com>,
        Josh Poimboeuf <jpoimboe@redhat.com>,
        Andrea Arcangeli <aarcange@redhat.com>,
        David Woodhouse <dwmw@amazon.co.uk>,
        Andi Kleen <ak@linux.intel.com>,
        Dave Hansen <dave.hansen@intel.com>,
        Casey Schaufler <casey.schaufler@intel.com>,
        Asit Mallick <asit.k.mallick@intel.com>,
        Arjan van de Ven <arjan@linux.intel.com>,
        Jon Masters <jcm@redhat.com>, linux-kernel@vger.kernel.org,
        x86@kernel.org
Subject: Re: [PATCH 2/2] x86/speculation: Provide application property based
 STIBP protection
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References: <cover.1537392876.git.tim.c.chen@linux.intel.com>
 <0c55c162a077aadbfd57878e2694e35292c1a29c.1537392876.git.tim.c.chen@linux.intel.com>
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On Wed, Sep 19, 2018 at 02:35:30PM -0700, Tim Chen wrote:
> This patch provides an application property based spectre_v2
> protection with STIBP against attack from another app from
> a sibling hyper-thread.  For security sensitive non-dumpable
> app, STIBP will be turned on before switching to it for Intel
> processors vulnerable to spectre_v2.

Why does that non dumpable thing make sense? Why not use the same
prctl() we already use for SSBD?