Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756611AbYH2G0W (ORCPT ); Fri, 29 Aug 2008 02:26:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755001AbYH2GUd (ORCPT ); Fri, 29 Aug 2008 02:20:33 -0400 Received: from py-out-1112.google.com ([64.233.166.176]:8645 "EHLO py-out-1112.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754981AbYH2GUb (ORCPT ); Fri, 29 Aug 2008 02:20:31 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:cc:in-reply-to:mime-version :content-type:content-transfer-encoding:content-disposition :references; b=YtdEBbAnSiMiRxe6/OWlLE3bH0LmG6JNsCvJyyndqfhqaUHokpaEP7tnx8tmn1ILA+ Nd7sLUYRwS6qLQiR2y0tZufbTpeuMIWI9Fb/nxLc1LQr9oFTkdR5/zsfugnTppvWMbni /8rSe5Gal4Fgr5jz6SZC/R0pUSjAeIiaFgFqQ= Message-ID: Date: Fri, 29 Aug 2008 08:20:30 +0200 From: "=?UTF-8?Q?Rafa=C5=82_Mi=C5=82ecki?=" To: "Jeremy Fitzhardinge" Subject: Re: [PATCH RFC] x86: check for and defend against BIOS memory corruption Cc: "Ingo Molnar" , "Alan Jenkins" , "Hugh Dickens" , "H. Peter Anvin" , "Linux Kernel Mailing List" In-Reply-To: <48B701FB.2020905@goop.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline References: <48B701FB.2020905@goop.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by alpha id m7T6Qkdq015202 Content-Length: 1205 Lines: 6 2008/8/28 Jeremy Fitzhardinge :> Some BIOSes have been observed to corrupt memory in the low 64k. This> patch does two things:> - Reserves all memory which does not have to be in that area, to> prevent it from being used as general memory by the kernel. Things> like the SMP trampoline are still in the memory, however.> - Clears the reserved memory so we can observe changes to it.> - Adds a function check_for_bios_corruption() which checks and reports on> memory becoming unexpectedly non-zero. Currently it's called in the> x86 fault handler, and the powermanagement debug output.>> RFC: What other places should we check for corruption in?>> [ Alan, Rafał: could you check you see:> 1: corruption messages> 2: no crashes> Thanks -J> ] I was trying my best to crash system with this patch applied and failed :) Works great. Just wonder if I should expect any printk fromcheck_for_bios_corruption? I do not see any: zajec@sony:~> dmesg | grep -i corrscanning 2 areas for BIOS corruption -- Rafał Miłecki????{.n?+???????+%?????ݶ??w??{.n?+????{??G?????{ay?ʇڙ?,j??f???h?????????z_??(?階?ݢj"???m??????G????????????&???~???iO???z??v?^?m???? ????????I?