Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753573AbYHRJPn (ORCPT ); Mon, 18 Aug 2008 05:15:43 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751156AbYHRJP0 (ORCPT ); Mon, 18 Aug 2008 05:15:26 -0400 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:58833 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752680AbYHRJPY (ORCPT ); Mon, 18 Aug 2008 05:15:24 -0400 Date: Mon, 18 Aug 2008 11:15:23 +0200 From: Pavel Machek To: Ingo Molnar Cc: David Fries , linux-kernel@vger.kernel.org, "Rafael J. Wysocki" , "H. Peter Anvin" , Thomas Gleixner Subject: Re: [PATCH] Fix i486 suspend to disk CR4 oops Message-ID: <20080818091522.GA6635@atrey.karlin.mff.cuni.cz> References: <20080818040340.GB17528@spacedout.fries.net> <20080818064120.GA28941@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080818064120.GA28941@elte.hu> User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2830 Lines: 69 > > * David Fries wrote: > > > arch/x86/power/cpu_32.c __save_processor_state calls read_cr4() only a > > i486 CPU doesn't have the CR4 register. Trying to read it produces an > > invalid opcode oops during suspend to disk. > > > > Added the check (boot_cpu_data.x86 >= 5) before reading the register. > > If the value to be written is zero the write is skipped. > > > > arch/x86/power/hibernate_asm_32.S > > done: swapped the use of %eax and %ecx to use jecxz for > > the zero test and jump over store to %cr4. > > restore_image: s/%ecx/%eax/ to be consistent with done: > > > > In addition to __save_processor_state, acpi_save_state_mem, > > efi_call_phys_prelog, and efi_call_phys_epilog had checks added (acpi > > restore was in assembly and already had a check for non-zero). There > > were other reads and writes of CR4, but MCE and virtualization > > shouldn't be executed on a i486 anyway. > > > > Signed-off-by: David Fries > > applied to tip/x86/urgent, thanks David. I've changed the conditions to > read_cr4_safe() instead - that's cleaner. Could you please check whether > the patch below works fine too on your box? > > Rafael, Pavel - does the commit below look good to you too? > > Ingo > > ----------------------> > >From e437fa5586f2e3b2aaeba649fae52be1f9a6eabb Mon Sep 17 00:00:00 2001 > From: David Fries > Date: Sun, 17 Aug 2008 23:03:40 -0500 > Subject: [PATCH] x86: fix i486 suspend to disk CR4 oops > > arch/x86/power/cpu_32.c __save_processor_state calls read_cr4() > only a i486 CPU doesn't have the CR4 register. Trying to read it > produces an invalid opcode oops during suspend to disk. > > Use the safe rc4 reading op instead. If the value to be written is > zero the write is skipped. > > arch/x86/power/hibernate_asm_32.S > done: swapped the use of %eax and %ecx to use jecxz for > the zero test and jump over store to %cr4. > restore_image: s/%ecx/%eax/ to be consistent with done: > > In addition to __save_processor_state, acpi_save_state_mem, > efi_call_phys_prelog, and efi_call_phys_epilog had checks added > (acpi restore was in assembly and already had a check for > non-zero). There were other reads and writes of CR4, but MCE and > virtualization shouldn't be executed on a i486 anyway. > > Signed-off-by: David Fries > Signed-off-by: Ingo Molnar Acked-by: Pavel Machek -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/