From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AH8x226Jwbs5NhWb80A9kTe1CZ24CZSGw7/r/SWXFsWW2tp4qeZs2eNYNPPNpUFV4uLxvU4lG0CB ARC-Seal: i=1; a=rsa-sha256; t=1518165706; cv=none; d=google.com; s=arc-20160816; b=IwjJyaxqKlnZLMXp6gS0H0JwFbjBQqkZezocdWcRk7SoeDbNfQ/ZCvgNX2WwwWXiow fXUCqNPe6BbJ9wFpa/esUdaWT7BZfuYYPUBsxlnV1j1ZWpZqGlUILVymGjFJkyE6t6U3 fbOgx4DouUAwlLOJBRXmqvoLy+X+lbOx7YSJh0G1zpnmUYr8yoUD1Wfo5oLlfX2G/IxM b/KEUJlDfSM/GtfPntsZmjSwPKjXJqy1qr+9NLqefz1vJ6mAUGqNl76WAuuOnUaxxtyY FmysngSqfwde57Zxxwme/faajTbwLInVjo0lVGwtryUk8FFv4Y8Bo/JfgVvfNQ65yO6q SQPQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=message-id:content-disposition:content-transfer-encoding :mime-version:in-reply-to:references:cc:user-agent:date:subject:to :from:dkim-signature:arc-authentication-results; bh=eaunVIETfFDLaA3GtCmW+EgrvBiMiGTL6uxNkHCthnE=; b=sL7kUDvtnldc4wQ6d/WM+xkglHUUjzK0NR07/++C7O6LNx8Ay1KYzxnsKraFpUmtFJ 7Aksfy2L7g+456wxi0mHaDEBGpeh0pixd6w/e1tW0Jj7rM3JYxw2VUCNay8CIgH3+MJS zh6MZmk9wr0uTvLxwtve9zppBNkzYeGvAmmtP/6FFnnA6J6WABamaccq2UvtVqeFeSCU uKt/ZhW2fLsuEavlRJqgtJBZIG5L3ZH6xYBZUP21PHW4/HhVburkILOxOMSMT4ABiruH uwbm8vTA2/jDG5MghoR1l4JHenok1bCuAwmwamBGThNElEYCUXKtaMoX0pIFm+P35Vyg Qt1Q== ARC-Authentication-Results: i=1; mx.google.com; dkim=temperror (no key for signature) header.i=@rainbow-software.org header.s=atlsmtp header.b=U85rqKjA; spf=pass (google.com: domain of linux@rainbow-software.org designates 80.94.52.26 as permitted sender) smtp.mailfrom=linux@rainbow-software.org Authentication-Results: mx.google.com; dkim=temperror (no key for signature) header.i=@rainbow-software.org header.s=atlsmtp header.b=U85rqKjA; spf=pass (google.com: domain of linux@rainbow-software.org designates 80.94.52.26 as permitted sender) smtp.mailfrom=linux@rainbow-software.org From: Ondrej Zary To: whiteheadm@acm.org Subject: Re: [BUG] x86 : i486 reporting to be vulnerable to Meltdown/Spectre_V1/Spectre_V2 Date: Fri, 9 Feb 2018 09:41:41 +0100 User-Agent: KMail/1.9.10 (enterprise35 0.20100827.1168748) Cc: David Laight , Arnd Bergmann , Alan Cox , David Woodhouse , Guenter Roeck , "Greg Kroah-Hartman" , Hugh Dickins , Dave Hansen , Jiri Kosina , Borislav Petkov , Kees Cook , Jamie Iles , Eduardo Valentin , Laura Abbott , Rik van Riel , Thomas Gleixner , Linux Kernel Mailing List References: <63ca28c5acb64de5ba33a81b6da5c507@AcuMS.aculab.com> In-Reply-To: X-KMail-QuotePrefix: > MIME-Version: 1.0 Content-Type: Text/Plain; charset="utf-8" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <201802090941.41782.linux@rainbow-software.org> X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1591354140743903681?= X-GMAIL-MSGID: =?utf-8?q?1591912123462414830?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On Thursday 08 February 2018, tedheadster wrote: > On Thu, Feb 8, 2018 at 12:02 PM, David Laight wrote: > > From: Arnd Bergmann > > > >> Sent: 08 February 2018 15:23 > > > > ... > > > >> The Winchip is what eventually turned into the VIA Nano, which does > >> have speculative execution, but I don't think the earlier C3 and C7 did, > >> they are much closer to the original Winchip design. > > > > We had terrible trouble getting (IIRC) the C7 to execute functions > > that were called in 16bit mode and returned in 32bit mode and v.v. > > (for boot code bios calls). > > The problems seemed to imply that it was caching return addresses > > and the translation (to uops) of the instructions that followed. > > So it would effectively decode the first few bytes in the wrong mode. > > So there might be scope for one of these attacks. > > > > OTOH these devices were so slow that I doubt any are used for anything > > serious - and certainly won't get a kernel update even if they are. > > > > Also worth nothing that the difference between the cpu and memory > > speeds is much lower - so far fewer instructions could be speculatively > > executed while waiting a cache miss. > > > > Tempting to disable everything. > > > > David > > You might think this absolutely crazy, but I would be willing to test > such systems if I can get my hands on the needed hardware that I lack. > I am already doing sanity testing on Intel > i486/i586/i586-MMX/i686-PentiumPro systems, I just don't have the > clone cpus (Cyrix, etc). > > While few people are using the 32bit kernel, I don't think we want to > kill it completely just yet. > > - Matthew I have a working Cyrix MII (was actively using it last year, now upgraded to a P3-based Celeron). Some AMD CPUs too - K6(maybe -2 or -3?), not sure about K5 and also a Rise mP6. But never got a WinChip. So the question is: what to test? BTW. Kernel was not able to identify mP6 CPU 6 years ago, patches were ignored. -- Ondrej Zary