From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753281Ab1ARA5w (ORCPT ); Mon, 17 Jan 2011 19:57:52 -0500 Received: from mga11.intel.com ([192.55.52.93]:40914 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753003Ab1ARA5v (ORCPT ); Mon, 17 Jan 2011 19:57:51 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.60,336,1291622400"; d="scan'208";a="878297876" Subject: Re: [PATCH]x86: make relocatable kernel work with new binutils -resend From: Shaohua Li To: Ingo Molnar Cc: lkml , Andrew Morton , "hpa@zytor.com" , "Lu, Hongjiu" , "Huang, Ying" In-Reply-To: <20110117101756.GB26819@elte.hu> References: <1295232361.1949.675.camel@sli10-conroe> <20110117101756.GB26819@elte.hu> Content-Type: text/plain; charset="UTF-8" Date: Tue, 18 Jan 2011 08:57:49 +0800 Message-ID: <1295312269.1949.725.camel@sli10-conroe> Mime-Version: 1.0 X-Mailer: Evolution 2.30.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2011-01-17 at 18:17 +0800, Ingo Molnar wrote: > * Shaohua Li wrote: > > > @@ -142,6 +140,11 @@ SECTIONS > > CACHELINE_ALIGNED_DATA(L1_CACHE_BYTES) > > > > DATA_DATA > > +#ifdef CONFIG_X86_32 > > + jiffies = jiffies_64; > > +#else > > + jiffies_64 = jiffies; > > +#endif > > I suspect this needs a comment, as to the unsuspecting reader it looks like black > magic :-) does this one look better? The CONFIG_RELOCATABLE is broken with new binutils, which will make boot panic. According to Lu Hongjiu, the affected binutils are from 2.20.51.0.12 to 2.21.51.0.3, which are release since Oct 22 this year. At least ubuntu 10.10 is using such binutils. see: http://sourceware.org/bugzilla/show_bug.cgi?id=12327 The reason of boot panic is we have 'jiffies = jiffies_64;' in vmlinux.lds.S. The jiffies isn't in any section. In kernel build, there is warning saying jiffies is an absolute address and can't be relocatable. At runtime, jiffies will have virtual address 0. Signed-off-by: Shaohua Li --- arch/x86/kernel/vmlinux.lds.S | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) Index: linux/arch/x86/kernel/vmlinux.lds.S =================================================================== --- linux.orig/arch/x86/kernel/vmlinux.lds.S 2011-01-18 08:32:22.000000000 +0800 +++ linux/arch/x86/kernel/vmlinux.lds.S 2011-01-18 08:57:09.000000000 +0800 @@ -34,11 +34,9 @@ OUTPUT_FORMAT(CONFIG_OUTPUT_FORMAT, CONF #ifdef CONFIG_X86_32 OUTPUT_ARCH(i386) ENTRY(phys_startup_32) -jiffies = jiffies_64; #else OUTPUT_ARCH(i386:x86-64) ENTRY(phys_startup_64) -jiffies_64 = jiffies; #endif #if defined(CONFIG_X86_64) && defined(CONFIG_DEBUG_RODATA) @@ -142,6 +140,15 @@ SECTIONS CACHELINE_ALIGNED_DATA(L1_CACHE_BYTES) DATA_DATA + /* + * Workaround a binutils (2.20.51.0.12 to 2.21.51.0.3) bug. + * This makes jiffies relocatable in such binutils + */ +#ifdef CONFIG_X86_32 + jiffies = jiffies_64; +#else + jiffies_64 = jiffies; +#endif CONSTRUCTORS /* rarely changed data like cpu maps */