From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756472Ab0JDPrF (ORCPT ); Mon, 4 Oct 2010 11:47:05 -0400 Received: from mx1.redhat.com ([209.132.183.28]:60177 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756387Ab0JDPrD (ORCPT ); Mon, 4 Oct 2010 11:47:03 -0400 Date: Mon, 4 Oct 2010 11:46:33 -0400 From: Jason Baron To: Daniel Drake Cc: Andres Salomon , Chris Ball , linux-kernel@vger.kernel.org, rostedt@goodmis.org, mingo@elte.hu Subject: Re: Dynamic nop selection breaks boot on Geode LX Message-ID: <20101004154633.GA2900@redhat.com> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Oct 02, 2010 at 08:16:19PM +0100, Daniel Drake wrote: > Hi, > > linux-next fails to boot on OLPC's XO-1 laptop based on Geode LX processor. > > This is because of > > commit f49aa448561fe9215f43405cac6f31eb86317792 > Author: Jason Baron > Date: Fri Sep 17 11:08:51 2010 -0400 > > jump label: Make dynamic no-op selection available outside of ftrace > > http://git.kernel.org/?p=linux/kernel/git/mingo/linux-2.6-x86.git;a=commitdiff;h=f49aa44 > > The Geode hangs inside the asm() statement inside arch_init_ideal_nop5. > > Any thoughts? > > I'm a bit out of my depth debugging assembly code, but will happily > take pointers and patches to help diagnose. > > cheers > Daniel Hi Daniel, looks like I moved dynamic no-op selection way too early in the boot - before the exception tables required to select invalid opcodes were even set up. The patch belows moves them later and should resolve this issue for you. thanks for narrowing it down! thanks, -Jason move arch_init_ideal_nop5 later arch_init_ideal_nop5() was being called from setup_arch() before the exception table was setup. Move it later into alternative_instructions(). Fixes a boot hang on OLPC's XO-1 laptop based on Geode LX processor. Reported-by: Daniel Drake Signed-off-by: Jason Baron --- arch/x86/kernel/alternative.c | 5 +++++ arch/x86/kernel/setup.c | 6 ------ 2 files changed, 5 insertions(+), 6 deletions(-) diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c index cb0e6d3..d8b5b21 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -454,6 +454,7 @@ extern struct paravirt_patch_site __start_parainstructions[], void __init alternative_instructions(void) { + unsigned long flags; /* The patching is not fully atomic, so try to avoid local interruptions that might execute the to be patched code. Other CPUs are not running. */ @@ -508,6 +509,10 @@ void __init alternative_instructions(void) (unsigned long)__smp_locks_end); restart_nmi(); + + local_irq_save(flags); + arch_init_ideal_nop5(); + local_irq_restore(flags); } /** diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index 468ccd2..85b02b6 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -112,7 +112,6 @@ #include #endif #include -#include /* * end_pfn only includes RAM, while max_pfn_mapped includes all e820 entries. @@ -690,7 +689,6 @@ void __init setup_arch(char **cmdline_p) { int acpi = 0; int k8 = 0; - unsigned long flags; #ifdef CONFIG_X86_32 memcpy(&boot_cpu_data, &new_cpu_data, sizeof(new_cpu_data)); @@ -1038,10 +1036,6 @@ void __init setup_arch(char **cmdline_p) x86_init.oem.banner(); mcheck_init(); - - local_irq_save(flags); - arch_init_ideal_nop5(); - local_irq_restore(flags); } #ifdef CONFIG_X86_32 -- 1.7.1