From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760746AbYDKPn0 (ORCPT ); Fri, 11 Apr 2008 11:43:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1759521AbYDKPnT (ORCPT ); Fri, 11 Apr 2008 11:43:19 -0400 Received: from gprs189-60.eurotel.cz ([160.218.189.60]:3046 "EHLO spitz.ucw.cz" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1759113AbYDKPnS (ORCPT ); Fri, 11 Apr 2008 11:43:18 -0400 Date: Fri, 11 Apr 2008 17:43:10 +0200 From: Pavel Machek To: Rusty Russell Cc: Linus Torvalds , Andi Kleen , "H. Anvin" , linux-kernel@vger.kernel.org, Ingo Molnar , lguest Subject: Re: [PATCH] Fix booting pentium+ with dodgy TSC Message-ID: <20080411154310.GA4492@ucw.cz> References: <200804061723.38766.rusty@rustcorp.com.au> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200804061723.38766.rusty@rustcorp.com.au> User-Agent: Mutt/1.5.9i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun 2008-04-06 17:23:38, Rusty Russell wrote: > Linus please apply. Almost by definition this patch can't make things worse. > > We handle a broken tsc these days, so no need to panic. We clear the TSC bit > when tsc_init decides it's unreliable (eg. under lguest w/ bad host TSC), > leading to bogus panic. > > Signed-off-by: Rusty Russell > > diff -r 5e0a39f4d07b arch/x86/kernel/cpu/bugs.c > --- a/arch/x86/kernel/cpu/bugs.c Sun Apr 06 13:40:39 2008 +1000 > +++ b/arch/x86/kernel/cpu/bugs.c Sun Apr 06 17:14:12 2008 +1000 > @@ -143,14 +143,6 @@ static void __init check_config(void) > #endif > > /* > - * If we configured ourselves for a TSC, we'd better have one! > - */ > -#ifdef CONFIG_X86_TSC > - if (!cpu_has_tsc) > - panic("Kernel compiled for Pentium+, requires TSC feature!"); > -#endif > - CONFIG_X86_TSC means 'cpu has _some_ tsc, rdmsr will work'. If you are confident noone will read broken tsc, please also remove the config option. It is meaningless after your patch. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html