From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 82D9BC433E0 for ; Mon, 3 Aug 2020 09:10:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5D4C0206E2 for ; Mon, 3 Aug 2020 09:10:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=mymailcheap.com header.i=@mymailcheap.com header.b="OZ4a7Jx7"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=flygoat.com header.i=@flygoat.com header.b="l7tP+RWG" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725926AbgHCJKi (ORCPT ); Mon, 3 Aug 2020 05:10:38 -0400 Received: from relay5.mymailcheap.com ([159.100.241.64]:40870 "EHLO relay5.mymailcheap.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725907AbgHCJKi (ORCPT ); Mon, 3 Aug 2020 05:10:38 -0400 Received: from relay4.mymailcheap.com (relay4.mymailcheap.com [137.74.199.117]) by relay5.mymailcheap.com (Postfix) with ESMTPS id B38D0206BC; Mon, 3 Aug 2020 09:10:34 +0000 (UTC) Received: from filter2.mymailcheap.com (filter2.mymailcheap.com [91.134.140.82]) by relay4.mymailcheap.com (Postfix) with ESMTPS id 72A8D3F1D0; Mon, 3 Aug 2020 11:10:32 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by filter2.mymailcheap.com (Postfix) with ESMTP id 3D6582A911; Mon, 3 Aug 2020 11:10:32 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=mymailcheap.com; s=default; t=1596445832; bh=Ab0IIpO/eIdkWbO25fAzy9lHE/XfBxoKYGaNcLmixyw=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=OZ4a7Jx7x/F8Nbf1iDJBbnPTFGFC2BSU0MAIBHO5FUBKJ05zM9gxlzp7NMdjcfssY 0NeGOnGgBOv5ljQWUAF4IIAEvCSZHDK72uEbsCuTeP8HOsyu4oEsHkZ1z4A0x3L/py LPFPwcWdf+iXh0ipdbf65BlRLaNJuDlqaU1TDTdk= X-Virus-Scanned: Debian amavisd-new at filter2.mymailcheap.com Received: from filter2.mymailcheap.com ([127.0.0.1]) by localhost (filter2.mymailcheap.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id Ve1O92gmF8my; Mon, 3 Aug 2020 11:10:30 +0200 (CEST) Received: from mail20.mymailcheap.com (mail20.mymailcheap.com [51.83.111.147]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by filter2.mymailcheap.com (Postfix) with ESMTPS; Mon, 3 Aug 2020 11:10:30 +0200 (CEST) Received: from [148.251.23.173] (ml.mymailcheap.com [148.251.23.173]) by mail20.mymailcheap.com (Postfix) with ESMTP id EA56940E55; Mon, 3 Aug 2020 09:10:27 +0000 (UTC) Authentication-Results: mail20.mymailcheap.com; dkim=pass (1024-bit key; unprotected) header.d=flygoat.com header.i=@flygoat.com header.b="l7tP+RWG"; dkim-atps=neutral AI-Spam-Status: Not processed Received: from [0.0.0.0] (n11212042148.netvigator.com [112.120.42.148]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mail20.mymailcheap.com (Postfix) with ESMTPSA id 488B44014B; Mon, 3 Aug 2020 09:01:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=flygoat.com; s=default; t=1596445314; bh=Ab0IIpO/eIdkWbO25fAzy9lHE/XfBxoKYGaNcLmixyw=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=l7tP+RWGkLX+oYhWEvwek/kl89XI5oSgVXOQ4zs0Of0CSye8s1oock0ONdO20tsrA kd9V46g4jiXt8TRkVsdoyaqjGHCh9huqh4bjiO6Zct8or7h+VQ/XFVIS2xybAcHBWr 0TH1WyS8E4mAAE91WjYshE8CVmG1mLyVl7GlquNs= Subject: Re: [PATCH] MIPS: Provide Kconfig option for default IEEE754 conformance mode To: "Maciej W. Rozycki" , Serge Semin Cc: Serge Semin , linux-mips@vger.kernel.org, Thomas Bogendoerfer , Paul Burton , Huacai Chen , Zhou Yanjie , =?UTF-8?B?5ZGo55Cw5p2wIChaaG91IFlhbmppZSk=?= , Liangliang Huang , linux-kernel@vger.kernel.org, "Maciej W. Rozycki" References: <20200731041018.1381642-1-jiaxun.yang@flygoat.com> <20200731061702.fxdfyxpvd6qrhoql@mobilestation> From: Jiaxun Yang Message-ID: Date: Mon, 3 Aug 2020 17:01:44 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Rspamd-Queue-Id: EA56940E55 X-Spamd-Result: default: False [1.40 / 10.00]; RCVD_VIA_SMTP_AUTH(0.00)[]; ARC_NA(0.00)[]; R_DKIM_ALLOW(0.00)[flygoat.com:s=default]; MID_RHS_MATCH_FROM(0.00)[]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; FREEMAIL_ENVRCPT(0.00)[gmail.com,zoho.com]; TO_MATCH_ENVRCPT_ALL(0.00)[]; TAGGED_RCPT(0.00)[]; MIME_GOOD(-0.10)[text/plain]; R_SPF_SOFTFAIL(0.00)[~all]; HFILTER_HELO_BAREIP(3.00)[148.251.23.173,1]; ML_SERVERS(-3.10)[148.251.23.173]; DKIM_TRACE(0.00)[flygoat.com:+]; DMARC_POLICY_ALLOW(0.00)[flygoat.com,none]; RCPT_COUNT_TWELVE(0.00)[12]; DMARC_POLICY_ALLOW_WITH_FAILURES(0.00)[]; RCVD_NO_TLS_LAST(0.10)[]; FROM_EQ_ENVFROM(0.00)[]; MIME_TRACE(0.00)[0:+]; ASN(0.00)[asn:24940, ipnet:148.251.0.0/16, country:DE]; FREEMAIL_CC(0.00)[gmail.com,vger.kernel.org,alpha.franken.de,kernel.org,lemote.com,zoho.com,wanyeetech.com,linux-mips.org]; SUSPICIOUS_RECIPS(1.50)[]; RCVD_COUNT_TWO(0.00)[2] X-Rspamd-Server: mail20.mymailcheap.com Sender: linux-mips-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org 在 2020/8/3 上午5:46, Maciej W. Rozycki 写道: > On Fri, 31 Jul 2020, Serge Semin wrote: > >>> Requested by downstream distros, a Kconfig option for default >>> IEEE754 conformance mode allows them to set their mode to >>> relaxed by default. >> That's what should have been here in the first place. Thanks! > Well, originally plans were there to have NaN interlinking implemented > and no such mess or desire for hacks like one here would result. Cf.: > > , > , > > and then: > > , > , > , > . > > You could well pick this work up and complete it if you like. Final > conclusions for further work were made here: > > , > , > . > > In the relaxed mode math programs may produce wrong results unless you > rebuild all your software for the correct NaN mode for the hardware used Unfortunately most of the hardware guys didn't understood the difficulty here. They decided to implement their hardware (P5600 & LS3A4000) as NaN2008 only. I was thinking about let Kernel drop SIGFPE exception was caused by mismatched NaN, as most applications don't rely on signaling NaN, but it is still a dirty hack. Not a good idea in general. Thanks. - Jiaxun > (in which case you don't need the relaxed setting in the first place). > > Maciej