From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vineet Gupta Subject: Re: [PATCH] frv: fix build failure Date: Wed, 6 Dec 2017 14:00:23 -0800 Message-ID: <817df34a-f471-99d7-aaa1-94e0ee9d5ffa@synopsys.com> References: <1511302233-5008-1-git-send-email-sudipm.mukherjee@gmail.com> <1511457437.32422.6.camel@synopsys.com> <3a6fe86e-7a66-56df-3b1d-e2e8cd3e6eae@synopsys.com> <20171203223226.GA3741@sudip-laptop> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from smtprelay.synopsys.com ([198.182.60.111]:45043 "EHLO smtprelay.synopsys.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751598AbdLFWAg (ORCPT ); Wed, 6 Dec 2017 17:00:36 -0500 In-Reply-To: <20171203223226.GA3741@sudip-laptop> Content-Language: en-US Sender: linux-arch-owner@vger.kernel.org List-ID: To: Sudip Mukherjee , Geert Uytterhoeven , Vineet Gupta Cc: Alexey Brodkin , "linux-kernel@vger.kernel.org" , "akpm@linux-foundation.org" , "linux-snps-arc@lists.infradead.org" , "linux-arch@vger.kernel.org" , Arnd Bergmann On 12/03/2017 02:32 PM, Sudip Mukherjee wrote: > On Mon, Nov 27, 2017 at 10:25:16AM -0800, Vineet Gupta wrote: >> +CC linux-arch, Arnd >> >> On 11/23/2017 09:17 AM, Alexey Brodkin wrote: >>> Hi Sudip, >>> >>> On Tue, 2017-11-21 at 22:10 +0000, Sudip Mukherjee wrote: > > > >> I understand the case/need for adding a weak/common abort() as a >> quick fix for handling such cases, but perhaps we should not and >> instead fix the rootcause. In this specific case, Claudiu mentioned >> that gcc was generating abort due to something like this (flagging a >> possible divide by zero due to >> -fno-isolate-erroneous-paths-dereference. >> >> a; >> >> fn1() { >> switch (a) >> case 0: >> return 1 / a; >> } >> >> Sudeep can you confirm that removing this hacking FRV build to not >> have this toggle fixes the abort issue. >> >> So the offending code needs to be fixed as in the end when that code >> path is taken system is hosed. > > The above case that you mentioned is indeed the case here. > mpihelp_divrem() in lib/mpi/mpih-div.c has this same divide by zero case. > > So, what should be the actual fix here? To remove the divide by zero. Or atleast have a __weak abort() defined in common code so all arches benefit from it ! -Vineet