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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D386AC4332F for ; Mon, 17 Oct 2022 13:11:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230139AbiJQNLe convert rfc822-to-8bit (ORCPT ); Mon, 17 Oct 2022 09:11:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53128 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230076AbiJQNLb (ORCPT ); Mon, 17 Oct 2022 09:11:31 -0400 Received: from eu-smtp-delivery-151.mimecast.com (eu-smtp-delivery-151.mimecast.com [185.58.85.151]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A1DDA26E7 for ; Mon, 17 Oct 2022 06:11:29 -0700 (PDT) Received: from AcuMS.aculab.com (156.67.243.121 [156.67.243.121]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id uk-mta-220-pP_sGcqFMfKL-aotPu7y3w-1; Mon, 17 Oct 2022 14:11:26 +0100 X-MC-Unique: pP_sGcqFMfKL-aotPu7y3w-1 Received: from AcuMS.Aculab.com (10.202.163.4) by AcuMS.aculab.com (10.202.163.4) with Microsoft SMTP Server (TLS) id 15.0.1497.42; Mon, 17 Oct 2022 14:11:24 +0100 Received: from AcuMS.Aculab.com ([::1]) by AcuMS.aculab.com ([::1]) with mapi id 15.00.1497.042; Mon, 17 Oct 2022 14:11:24 +0100 From: David Laight To: 'Huacai Chen' , Arnd Bergmann , Huacai Chen CC: "loongarch@lists.linux.dev" , "linux-arch@vger.kernel.org" , Xuefeng Li , Guo Ren , Xuerui Wang , Jiaxun Yang , "linux-kernel@vger.kernel.org" Subject: RE: [PATCH V3] LoongArch: Add unaligned access support Thread-Topic: [PATCH V3] LoongArch: Add unaligned access support Thread-Index: AQHY4ieF1YXwdHBLG0is9Yy/swO7xa4SjkhQ Date: Mon, 17 Oct 2022 13:11:24 +0000 Message-ID: <39ea2a6fee654b68974ef38237a61e80@AcuMS.aculab.com> References: <20221017125209.2639531-1-chenhuacai@loongson.cn> In-Reply-To: <20221017125209.2639531-1-chenhuacai@loongson.cn> Accept-Language: en-GB, en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.202.205.107] MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: aculab.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org From: Huacai Chen > Sent: 17 October 2022 13:52 > > Loongson-2 series (Loongson-2K500, Loongson-2K1000) don't support > unaligned access in hardware, while Loongson-3 series (Loongson-3A5000, > Loongson-3C5000) are configurable whether support unaligned access in > hardware. This patch add unaligned access emulation for those LoongArch > processors without hardware support. > ..... > + } else if (insn.reg2i12_format.opcode == fstd_op || > + insn.reg3_format.opcode == fstxd_op) { > + value = read_fpr(insn.reg2i12_format.rd); > + res = unaligned_write(addr, value, 8); > + if (res) > + goto fault; > + } else if (insn.reg2i12_format.opcode == fsts_op || > + insn.reg3_format.opcode == fstxs_op) { > + value = read_fpr(insn.reg2i12_format.rd); > + res = unaligned_write(addr, value, 4); > + if (res) > + goto fault; Are those right? Shouldn't something be converting from 'double' to 'float' in there? And generating SIGFPE (?) if the exponent is out of range. (And the same for write_fpr().) David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)