From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753454Ab2ACOFj (ORCPT ); Tue, 3 Jan 2012 09:05:39 -0500 Received: from service87.mimecast.com ([91.220.42.44]:33972 "EHLO service87.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752572Ab2ACOFg convert rfc822-to-8bit (ORCPT ); Tue, 3 Jan 2012 09:05:36 -0500 Message-ID: <4F030B34.1090705@arm.com> Date: Tue, 03 Jan 2012 14:05:40 +0000 From: Marc Zyngier User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:9.0) Gecko/20111220 Thunderbird/9.0 MIME-Version: 1.0 To: Rob Herring CC: Yang Bai , Joerg Roedel , Russell King , Thomas Gleixner , Santosh Shilimkar , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , Will Deacon Subject: Re: [PATCH] arm: Fix linux-next compile error in arch/arm/common/gic.c References: <1325521990-4445-1-git-send-email-joerg.roedel@amd.com> <4F02E377.2050409@arm.com> <4F03085F.4060008@gmail.com> In-Reply-To: <4F03085F.4060008@gmail.com> X-Enigmail-Version: 1.3.4 X-OriginalArrivalTime: 03 Jan 2012 14:05:28.0701 (UTC) FILETIME=[BF787AD0:01CCCA20] X-MC-Unique: 112010314053200801 Content-Type: text/plain; charset=WINDOWS-1252 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/01/12 13:53, Rob Herring wrote: > > > On 01/03/2012 05:16 AM, Marc Zyngier wrote: >> [Adding Will to the loop as he's the author of the logical map stuff, >> though I'm not sure he'll read that before next week...] >> >> On 03/01/12 00:44, Yang Bai wrote: >>> On Tue, Jan 3, 2012 at 12:33 AM, Joerg Roedel wrote: >>>> With CONFIG_SMP=n the following compile error occurs: >>>> >>>> CC arch/arm/common/gic.o >>>> arch/arm/common/gic.c: In function 'gic_init_bases': >>>> arch/arm/common/gic.c:679:4: error: implicit declaration of function 'cpu_logical_map' [-Werror=implicit-function-declaration] >>>> cc1: some warnings being treated as errors >>>> >>>> This patch fixes the problem. >>>> >>>> Cc: Marc Zyngier >>>> Cc: Thomas Gleixner >>>> Cc: Santosh Shilimkar >>>> Cc: Rob Herring >>>> Cc: linux-arm-kernel@lists.infradead.org >>>> Cc: linux-kernel@vger.kernel.org >>>> Signed-off-by: Joerg Roedel >>>> --- >>>> arch/arm/common/gic.c | 5 ++++- >>>> 1 files changed, 4 insertions(+), 1 deletions(-) >>>> >>>> diff --git a/arch/arm/common/gic.c b/arch/arm/common/gic.c >>>> index b2dc2dd..b33f6b0 100644 >>>> --- a/arch/arm/common/gic.c >>>> +++ b/arch/arm/common/gic.c >>>> @@ -676,7 +676,10 @@ void __init gic_init_bases(unsigned int gic_nr, int irq_start, >>>> } >>>> >>>> for_each_possible_cpu(cpu) { >>>> - unsigned long offset = percpu_offset * cpu_logical_map(cpu); >>>> + unsigned long offset = percpu_offset; >>>> +#ifdef CONFIG_SMP >>>> + offset *= cpu_logical_map(cpu); >>>> +#endif >>>> *per_cpu_ptr(gic->dist_base.percpu_base, cpu) = dist_base + offset; >>>> *per_cpu_ptr(gic->cpu_base.percpu_base, cpu) = cpu_base + offset; >>>> } >>>> -- >>>> 1.7.5.4 >>>> >>>> >>> >>> Is this the right way to fix it? Or shall we do like this: >>> >>> #ifdef CONFIG_SMP >>> ... >>> #else >>> #define cpu_logical_map() 1 >>> #endif >>> >>> and leave the gic.c code unchanged. > > IIRC, part of the problem is asm/smp.h is only included by linux/smp.h > for CONFIG_SMP, so this would have to change. Doing that could easily > break other arches. Ah... good point. >> >> Well, both patches are wrong. In the UP case (and assuming we're running >> on physical CPU 0), offset should be 0. >> >> The second patch would be my favorite approach, except that >> cpu_logical_map(x) should return either "x" or 0. And I'm not sure how >> to handle the (unlikely?) case of running a UP kernel on a secondary CPU... > > Wouldn't this be the case with 2 AMP instances of Linux running? Yes, or kexec-ing a UP kernel on a secondary CPU. It really looks like we ought to make this cpu_logical_map() independent from CONFIG_SMP. M. -- Jazz is not dead. It just smells funny...