linux-kernel - Re: [PATCH v3 2/6] x86/uaccess: Avoid barrier_nospec() in 64-bit __get

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: <CAHk-=wh0tnmhigqc=2wN-0OtdLhJU-9eYXgpFgbOR6eKrsh75A@mail.gmail.com>
Date: Fri, 22 Nov 2024 10:16:58 -0800
From: Linus Torvalds <torvalds@...ux-foundation.org>
To: Christophe Leroy <christophe.leroy@...roup.eu>
Cc: Josh Poimboeuf <jpoimboe@...nel.org>, David Laight <David.Laight@...lab.com>, 
	"x86@...nel.org" <x86@...nel.org>, 
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, Thomas Gleixner <tglx@...utronix.de>, 
	Borislav Petkov <bp@...en8.de>, Peter Zijlstra <peterz@...radead.org>, 
	Pawan Gupta <pawan.kumar.gupta@...ux.intel.com>, Waiman Long <longman@...hat.com>, 
	Dave Hansen <dave.hansen@...ux.intel.com>, Ingo Molnar <mingo@...hat.com>, 
	Michael Ellerman <mpe@...erman.id.au>, 
	"linuxppc-dev@...ts.ozlabs.org" <linuxppc-dev@...ts.ozlabs.org>, Andrew Cooper <andrew.cooper3@...rix.com>, 
	Mark Rutland <mark.rutland@....com>, "Kirill A . Shutemov" <kirill@...temov.name>
Subject: Re: [PATCH v3 2/6] x86/uaccess: Avoid barrier_nospec() in 64-bit __get_user()

On Fri, 22 Nov 2024 at 01:20, Christophe Leroy
<christophe.leroy@...roup.eu> wrote:
>
> On powerpc for this kind of stuff I have been using do { } while (0);
> with a break; in the middle, see for instance __put_user() or
> __get_user_size_allowed() in arch/powerpc/include/asm/uaccess.h

Oh, that's indeed a nicer syntax. I'll try to keep that in mind for
next time I come up with disgusting macros (although as mentioned, in
this case I think we're better off not playing that particular game at
all).

                Linus