linux-kernel - Re: [patch V2 5/5] x86/kaiser: Add boottime disable switch

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20171127124952.m6rw72kkufzyneco@hirez.programming.kicks-ass.net>
Date:   Mon, 27 Nov 2017 13:49:52 +0100
From:   Peter Zijlstra <peterz@...radead.org>
To:     Thomas Gleixner <tglx@...utronix.de>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Andy Lutomirski <luto@...nel.org>,
        Ingo Molnar <mingo@...nel.org>, Borislav Petkov <bp@...en8.de>,
        Brian Gerst <brgerst@...il.com>,
        Denys Vlasenko <dvlasenk@...hat.com>,
        "H. Peter Anvin" <hpa@...or.com>,
        Josh Poimboeuf <jpoimboe@...hat.com>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Rik van Riel <riel@...hat.com>, daniel.gruss@...k.tugraz.at,
        hughd@...gle.com, keescook@...gle.com, linux-mm@...ck.org,
        michael.schwarz@...k.tugraz.at, moritz.lipp@...k.tugraz.at,
        richard.fellner@...dent.tugraz.at
Subject: Re: [patch V2 5/5] x86/kaiser: Add boottime disable switch

On Mon, Nov 27, 2017 at 12:50:45PM +0100, Thomas Gleixner wrote:
> On Mon, 27 Nov 2017, Peter Zijlstra wrote:
> > On Mon, Nov 27, 2017 at 10:48:46AM +0100, Peter Zijlstra wrote:

> > > So in patch 15 Andy notes that we should probably also disable the
> > > SYSCALL trampoline when we disable KAISER.
> > > 
> > >   https://lkml.kernel.org/r/20171124172411.19476-16-mingo@kernel.org
> > 
> > Could be a simple as this.. but I've not tested.
> 
> That's only one part of it. I think we need to fiddle with the exit side as
> well.

So I assumed that the patches were bisectable. From that I figured the
exit path (patch 14 in that set) would work either way.