linux-kernel - Re: [RFC PATCH 00/16] PTI support for x86-32

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: <20180123143831.2d769f9d@alans-desktop>
Date:   Tue, 23 Jan 2018 14:38:31 +0000
From:   Alan Cox <gnomes@...rguk.ukuu.org.uk>
To:     "H. Peter Anvin" <hpa@...or.com>
Cc:     Linus Torvalds <torvalds@...ux-foundation.org>,
        Nadav Amit <nadav.amit@...il.com>,
        Joerg Roedel <joro@...tes.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...nel.org>,
        the arch/x86 maintainers <x86@...nel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        "open list:MEMORY MANAGEMENT" <linux-mm@...ck.org>,
        Andy Lutomirski <luto@...nel.org>,
        Dave Hansen <dave.hansen@...el.com>,
        Josh Poimboeuf <jpoimboe@...hat.com>,
        Juergen Gross <jgross@...e.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Borislav Petkov <bp@...en8.de>, Jiri Kosina <jkosina@...e.cz>,
        Boris Ostrovsky <boris.ostrovsky@...cle.com>,
        Brian Gerst <brgerst@...il.com>,
        David Laight <David.Laight@...lab.com>,
        Denys Vlasenko <dvlasenk@...hat.com>,
        Eduardo Valentin <eduval@...zon.com>,
        Greg KH <gregkh@...uxfoundation.org>,
        Will Deacon <will.deacon@....com>,
        "Liguori, Anthony" <aliguori@...zon.com>,
        Daniel Gruss <daniel.gruss@...k.tugraz.at>,
        Hugh Dickins <hughd@...gle.com>,
        Kees Cook <keescook@...gle.com>,
        Andrea Arcangeli <aarcange@...hat.com>,
        Waiman Long <llong@...hat.com>, Joerg Roedel <jroedel@...e.de>
Subject: Re: [RFC PATCH 00/16] PTI support for x86-32

> of timing requirements vs complexity.  At least theoretically one could
> imagine a machine which would take the trap after the speculative
> machine had already chased the pointer loop several levels down; this
> would most likely mean separate uops to allow for the existing
> out-of-order machine to do the bookkeeping.

It's not quite the same but in the IA-64 case you can write itanium code
that does exactly that. The speculation is expressed in software not
hardware (because you can trigger a load, then check later if it worked
out and respond appripriately).

Alan