Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933529AbaJVW3m (ORCPT ); Wed, 22 Oct 2014 18:29:42 -0400 Received: from mailapp01.imgtec.com ([195.59.15.196]:64410 "EHLO mailapp01.imgtec.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933487AbaJVW3j (ORCPT ); Wed, 22 Oct 2014 18:29:39 -0400 Date: Wed, 22 Oct 2014 23:29:36 +0100 From: James Hogan To: John Crispin CC: , "ralf@linux-mips.org" , "linux-mips@linux-mips.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH] mips: add arch_trigger_all_cpu_backtrace() function Message-ID: <20141022222936.GE12296@jhogan-linux.le.imgtec.org> References: <1061520101.169091413960858532.JavaMail.weblogic@epmlwas02b> <544758AB.3060100@openwrt.org> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Disposition: inline In-Reply-To: <544758AB.3060100@openwrt.org> User-Agent: Mutt/1.5.22 (2013-10-16) X-Originating-IP: [192.168.154.101] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi John, On Wed, Oct 22, 2014 at 09:11:39AM +0200, John Crispin wrote: > On 22/10/2014 08:54, Eunbong Song wrote: > >>> +void arch_trigger_all_cpu_backtrace(bool); +#define > >>> arch_trigger_all_cpu_backtrace arch_trigger_all_cpu_backtrace > > > >> What is the purpose of this define ? is this maybe a leftover from > >> some regex/cleanups ? > > > > Hi John. > > Actually, I just follow the same function of sparc architecture. > > You can find this in arch/sparc/include/asm/irq_64.h as below > > > > void arch_trigger_all_cpu_backtrace(bool); > > #define arch_trigger_all_cpu_backtrace arch_trigger_all_cpu_backtrace > > > > I guess this is used for conditional compile. > > See below. > > include/linux/nmi.h > > #ifdef arch_trigger_all_cpu_backtrace > > static inline bool trigger_all_cpu_backtrace(void) > > { > > arch_trigger_all_cpu_backtrace(true); > > > > return true; > > } > > static inline bool trigger_allbutself_cpu_backtrace(void) > > { > > arch_trigger_all_cpu_backtrace(false); > > return true; > > } > > #else > > static inline bool trigger_all_cpu_backtrace(void) > > { > > return false; > > } > > static inline bool trigger_allbutself_cpu_backtrace(void) > > { > > return false; > > } > > #endif > > > > Thanks. > >> John > > > > i don't see how this is required for conditional compiles. the code > define a->a which is bogus i think. It's a pretty common pattern in the asm headers, in order to allow generic code to use the preprocessor to see whether it was defined or not. Cheers James -- 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/