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Subject: Re: STIBP by default.. Revert?
From:   Dave Hansen <dave@sr71.net>
In-Reply-To: <nycvar.YFH.7.76.1811182309540.21108@cbobk.fhfr.pm>
Date:   Sun, 18 Nov 2018 14:35:20 -0800
Cc:     Linus Torvalds <torvalds@linux-foundation.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Peter Zijlstra <peterz@infradead.org>,
        Josh Poimboeuf <jpoimboe@redhat.com>,
        Andrea Arcangeli <aarcange@redhat.com>,
        David Woodhouse <dwmw@amazon.co.uk>,
        Andi Kleen <ak@linux.intel.com>,
        Tim Chen <tim.c.chen@linux.intel.com>,
        Casey Schaufler <casey.schaufler@intel.com>,
        Linux List Kernel Mailing <linux-kernel@vger.kernel.org>,
        the arch/x86 maintainers <x86@kernel.org>,
        stable@vger.kernel.org
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References: <CAHk-=wg-9FUGU=grF4gKDq1sm1m39Jbs3A_iyLbSSntU47ncwg@mail.gmail.com> <nycvar.YFH.7.76.1811182222230.21108@cbobk.fhfr.pm> <CAHk-=whH2daKsZTqVPb-G9mJ1g15XMse7j-9YqN+yBYk7M9=Dw@mail.gmail.com> <nycvar.YFH.7.76.1811182309540.21108@cbobk.fhfr.pm>
To:     Jiri Kosina <jikos@kernel.org>
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> On Nov 18, 2018, at 2:17 PM, Jiri Kosina <jikos@kernel.org> wrote:
> 
> It's probably not just browsers, but anything running JITed sandboxed 
> code. So the most straightforward way might be the prctl() aproach, where 
> userspace would claim "I do care about this, please fix it up for me". So 
> prctl() + perhaps SECCOMP.

Yeah, the prctl() shifts the pain to the right place: folks explicitly opting in.  Always-on seemed way too draconian to me.