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=-8.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS autolearn=ham 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 8D103C433E0 for ; Mon, 15 Feb 2021 14:28:54 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id A8B8A64E40 for ; Mon, 15 Feb 2021 14:28:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A8B8A64E40 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=nocrew.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:43798 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lBers-0002j5-LF for qemu-devel@archiver.kernel.org; Mon, 15 Feb 2021 09:28:52 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:47682) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lBerJ-0002Jt-1m for qemu-devel@nongnu.org; Mon, 15 Feb 2021 09:28:17 -0500 Received: from ste-pvt-msa2.bahnhof.se ([213.80.101.71]:56565) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lBerH-0002aE-8Z for qemu-devel@nongnu.org; Mon, 15 Feb 2021 09:28:16 -0500 Received: from localhost (localhost [127.0.0.1]) by ste-pvt-msa2.bahnhof.se (Postfix) with ESMTP id C94633F6FA; Mon, 15 Feb 2021 15:28:11 +0100 (CET) X-Virus-Scanned: Debian amavisd-new at bahnhof.se Received: from ste-pvt-msa2.bahnhof.se ([127.0.0.1]) by localhost (ste-ftg-msa2.bahnhof.se [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 8_W5gLJVr-2L; Mon, 15 Feb 2021 15:28:10 +0100 (CET) Received: by ste-pvt-msa2.bahnhof.se (Postfix) with ESMTPA id B67DC3F6A7; Mon, 15 Feb 2021 15:28:09 +0100 (CET) Date: Mon, 15 Feb 2021 15:28:09 +0100 From: Fredrik Noring To: Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= , "Maciej W. Rozycki" Subject: Re: [RFC PATCH 41/42] tests/acceptance: Test R5900 CPU with BusyBox from Sony PS2 Message-ID: References: <20210214175912.732946-1-f4bug@amsat.org> <20210214175912.732946-42-f4bug@amsat.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20210214175912.732946-42-f4bug@amsat.org> Received-SPF: softfail client-ip=213.80.101.71; envelope-from=noring@nocrew.org; helo=ste-pvt-msa2.bahnhof.se X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_LOW=-0.7, SPF_HELO_NONE=0.001, SPF_SOFTFAIL=0.665 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Thomas Huth , Aleksandar Rikalo , Richard Henderson , qemu-devel@nongnu.org, Laurent Vivier , Wainer dos Santos Moschetta , Cleber Rosa , Alex =?utf-8?Q?Benn=C3=A9e?= , Aurelien Jarno Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Sun, Feb 14, 2021 at 06:59:11PM +0100, Philippe Mathieu-Daudé wrote: > Test BusyBox on the R5900 CPU with 2 different binaries: > > - o32 32-bit (statically linked) > - o32 64-bit (dynamically linked, uses multimedia instructions) R5900/libc update: Gnu libc for o32 was merged some time ago so any recent Gentoo etc. will do fine without patches. For n32, there's a provisional patch that needs reworking to get merged (to have libc emulate DMULT etc. rather than the kernel/QEMU).[1] Musl has a pending patch I posted[2] about a month ago. Musl is o32 only, for all MIPS, but other than that it's got two significant advantages over Gnu libc: 1. excellent support for static linking; 2. program sizes are often much smaller, more than 5x smaller observed. An important detail is that since the R5900 FPU isn't compliant with the IEEE 754 standard[3] it's normally wholly emulated by either libc or the kernel, to comply with the MIPS psABI. The R5900 hardware FPU can perhaps be enabled with a future R5900 ELF ABI annotation extension.[4] Finally, the situation with the 128-bit R5900 general purpose registers (GPRs) is not fully resolved with the Linux kernel. The best case scenario, I believe, would be to have them available at all times.[5] Fredrik References: [1] https://lists.gnu.org/archive/html/qemu-devel/2019-01/msg00974.html [2] https://www.openwall.com/lists/musl/2020/12/24/2 [3] https://github.com/frno7/linux/wiki/R5900-floating-point-unit-(FPU) [4] https://github.com/frno7/linux/issues/3 [5] https://github.com/frno7/linux/issues/5