Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759024AbaJ3Kom (ORCPT ); Thu, 30 Oct 2014 06:44:42 -0400 Received: from mail-lb0-f180.google.com ([209.85.217.180]:48192 "EHLO mail-lb0-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758155AbaJ3Kok (ORCPT ); Thu, 30 Oct 2014 06:44:40 -0400 MIME-Version: 1.0 In-Reply-To: <2095416.INZmt8AD1y@wuerfel> References: <1414139071-3818-1-git-send-email-lftan@altera.com> <1414139071-3818-30-git-send-email-lftan@altera.com> <2095416.INZmt8AD1y@wuerfel> Date: Thu, 30 Oct 2014 18:44:37 +0800 X-Google-Sender-Auth: iTlzjQ8buPDzWNS-h5Ibuo2UiqM Message-ID: Subject: Re: [PATCH v5 29/29] nios2: Build infrastructure From: Ley Foon Tan To: Arnd Bergmann Cc: Linux-Arch , "linux-kernel@vger.kernel.org" , "linux-doc@vger.kernel.org" , Chung-Lin Tang Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Oct 28, 2014 at 9:38 PM, Arnd Bergmann wrote: > On Friday 24 October 2014 16:24:31 Ley Foon Tan wrote: >> +DECLARE_EXPORT(__gcc_bcmp); >> +DECLARE_EXPORT(__divdi3); >> +DECLARE_EXPORT(__divsi3); >> +DECLARE_EXPORT(__moddi3); >> +DECLARE_EXPORT(__modsi3); >> +DECLARE_EXPORT(__udivdi3); >> +DECLARE_EXPORT(__udivmoddi4); >> +DECLARE_EXPORT(__udivsi3); >> +DECLARE_EXPORT(__umoddi3); >> +DECLARE_EXPORT(__umodsi3); >> +DECLARE_EXPORT(__muldi3); >> > > I don't remember what all of these are, but at least some of them seem > to be concerned with 64-bit division. By convention, we don't provide those > in the Linux kernel but instead require all code to use the do_div() > macro instead. Do you mean kernel doesn't support 64 bit division result for a 32-bit architecture? Because do_div() only support 32-bit division result for 32-bit architecture. Compiler will auto generate call to __divdi3() for the following example code. This means loadable module will have compilation error if we don't export symbol for __divdi3, but built-in module is fine. Is this an expectation? Or we can keep 64-bit division symbols here since they are no harm (they are software emulation when without hardware divider). long long a, b, c; a = b / c; Regards Ley Foon -- 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/