From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AH8x227uejJtsQ41YWhh2y3sjZw0nbPJCGddwJy/m1M6uoqOwVXqgs77UCGAuMiEbur2APJ7dUB7 ARC-Seal: i=1; a=rsa-sha256; t=1518097797; cv=none; d=google.com; s=arc-20160816; b=ihKV5Ambf2ZudsBG87S3k6RlsJCb7sfLuwe74NP5srcMeH/24dcK4myDyxUy4yy13n ejmJT0iIOMKyTBJQRlNuWxNunJ/kg1Biit0iz8IuEXyMygtHYLNLCKxfFwPOg1wJvFVW OUrKNbOVlpayY3uEB/1xs6Aq3hN50YIfzUetaPb6kPCjfIxz97HW3kQOfY4q5ZKtmPWg OHw/ST6SGqjWwe8aEbWrQDAggvHFpvlPYj+NGJV7ZvxNDSkAJpNs4Iynyq2Y/07kIWDM RSv7Nj3Ix6ifDDf4c4eEQeW+rd8w3LAte8S74dIh/QMlDxR+jA1q/Qre5vFIZc6ua05R S+Tg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=content-transfer-encoding:mime-version:organization:references :in-reply-to:message-id:subject:cc:to:from:date :arc-authentication-results; bh=+diRqNWzBlxsRAlhEdQYMIXtq6QkpgBNkTJezZ2VHbY=; b=uLNSD1NfAsFGZQC5kAv5wgaPokbuQVdAOD3QiAbSZ96k2YXL9gF55nC3aTUnwY5iOG Cxhn4sZeITP9YATozN72mU3VAaJmxys4X9IlfKGRCH1j1U/LSkIpYtPKwj0T8wYenwvc rID8FtEh9sDkVog5JWm7PsEYVG8uNAT62ZVL6QRN9kmdKQVJfJjfFA1Br194Sfm3HX0S GW//Opgoa1DodLa3LfZMztdh9o4aZ1N6gqWNiBvjHNfrhmT17WcEljEX3sAvB6dFRQor ffD9wKYTvvLV1Oy1LcVxNiiGcQ90oHjk4lwLQ7HxJ57jHD9x7PphCxRXUw0Zv04QSUVM tIZQ== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of gnomes@lxorguk.ukuu.org.uk designates 82.70.14.225 as permitted sender) smtp.mailfrom=gnomes@lxorguk.ukuu.org.uk Authentication-Results: mx.google.com; spf=pass (google.com: domain of gnomes@lxorguk.ukuu.org.uk designates 82.70.14.225 as permitted sender) smtp.mailfrom=gnomes@lxorguk.ukuu.org.uk Date: Thu, 8 Feb 2018 13:49:08 +0000 From: Alan Cox To: Ondrej Zary Cc: whiteheadm@acm.org, David Woodhouse , Guenter Roeck , "Greg Kroah-Hartman" , Hugh Dickins , dave.hansen@linux.intel.com, jikos@kernel.org, Borislav Petkov , Kees Cook , Jamie Iles , eduval@amazon.com, labbott@redhat.com, Rik van Riel , Thomas Gleixner , linux-kernel@vger.kernel.org Subject: Re: [BUG] x86 : i486 reporting to be vulnerable to Meltdown/Spectre_V1/Spectre_V2 Message-ID: <20180208134908.4b516794@alans-desktop> In-Reply-To: <201802070918.18978.linux@rainbow-software.org> References: <1517950494.3677.30.camel@infradead.org> <201802070918.18978.linux@rainbow-software.org> Organization: Intel Corporation X-Mailer: Claws Mail 3.15.1-dirty (GTK+ 2.24.31; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1591354140743903681?= X-GMAIL-MSGID: =?utf-8?q?1591840915878930272?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: > What about Pentium II and 3? I'm using 5 such machines (and also a Pentium > MMX). I've tried a spectre test before and it wasn't reading anything useful. > Don't know about meltdown. Is there a complete test program? (The web is so > full of crap that even google can't find anything useful.) Pentium MMX does not speculate. Pentium II does. For meltdown there are some reasonably easy tests to run to look for a positive. Proving a negative is much much harder however and as far as I am aware nobody has done a full evaluation of processors that old. For x86 speculation came in (as far as I can tell) in AMD Am5x86 Cyrix 5x86, but branch predictors are disabled by default according to the docs Cyrix 6x86, branch prediction on by default Pentium Pro There are later processors that don't have speculation: Quark series, Nat Semi/Cyrix Geode, earliest AMD geode (I think), some Intel Atom processors. The more obscure ones - the Transmeta apparently may, the IDT Winchip documentation strongly implies it doesn't, the Vortex86 (aka SiS55X/Rise mP6) says it doesn't and things like the NexGen I have no idea about. The problem is that it's very hard to definitively answer questions on these processors and vulnerabilities like they are obsolete, almost nobody uses them for anything but retro stuff and the return on the effort of figuring out defiitive answers is close to nil. Alan