From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757215Ab3HGGve (ORCPT ); Wed, 7 Aug 2013 02:51:34 -0400 Received: from mail.skyhub.de ([78.46.96.112]:38216 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757134Ab3HGGvd (ORCPT ); Wed, 7 Aug 2013 02:51:33 -0400 Date: Wed, 7 Aug 2013 08:51:19 +0200 From: Borislav Petkov To: Torsten Kaiser Cc: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Jacob Shin , Johannes Hirte , linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] x86, AMD: Make cpu_has_amd_erratum() use the correct struct cpuinfo_x86 Message-ID: <20130807065119.GA17920@pd.tnic> References: <20130723194049.59ee11bb@googlemail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20130723194049.59ee11bb@googlemail.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 23, 2013 at 07:40:49PM +0200, Torsten Kaiser wrote: > cpu_has_amd_erratum() is buggy, because it uses the per-cpu cpu_info > before it is filled by smp_store_boot_cpu_info() / smp_store_cpu_info(). > > If early microcode loading is enabled its collect_cpu_info_amd_early() will > fill ->x86 and so the fallback to boot_cpu_data is not used. > But ->x86_vendor was not filled and is still 0 == X86_VENDOR_INTEL resulting in > no errata fixes getting applied and my system hangs on boot. > > Using cpu_info in cpu_has_amd_erratum() is wrong anyway: Its only caller > init_amd() will have a struct cpuinfo_x86 as parameter and the set_cpu_bug() > that is controlled by cpu_has_amd_erratum() also only uses that struct. > > So pass the struct cpuinfo_x86 from init_amd() to cpu_has_amd_erratum() and > the broken fallback can be dropped. > > I also added an WARN_ON() into the vendor check because init_amd() can only > be used by AMD CPUs and if the current failure hadn't been silent this bug > would have been much more obvious. > > V2: At request of Borislav Petkov: BUG_ON -> WARN_ON and subject change > > Signed-off-by: Torsten Kaiser Acked-by: Borislav Petkov -- Regards/Gruss, Boris. Sent from a fat crate under my desk. Formatting is fine. --