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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B7259CAC5B5 for ; Mon, 29 Sep 2025 00:19:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To: Content-Transfer-Encoding:Content-Type:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=Lt8AIN8qAukSlVfx8WoOC+JRHZZ9SvnJjxUFLq4fz1U=; b=nAmsJjxorLtdiCH7SxFESZDbCB 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TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250928_171930_217233_3E0065A2 X-CRM114-Status: GOOD ( 14.77 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, Sep 19, 2025 at 07:40:25PM +0100, Will Deacon wrote: > Big-endian arm64 configurations are vanishingly rare, yet we still claim > to support them in Linux despite very limited testing or visible > interest. Supporting big-endian adds unnecessary burden to reviewers and > contributors which, without any known active users, is hard to justify. > For example, recent work to improve our futex routines and to implement > nested virtualisation support is non-trivially complicated by having to > support both big- and little-endianness. >=20 > Back in 2019 [1], it was claimed that Huawei were using arm64 big-endian > machines in their telecommunication products but I don't know whether > that's still the case and certainly haven't seen any patch contributions > to help support or maintain it. >=20 > Make CPU_BIG_ENDIAN depend on BROKEN as an initial deprecation step > towards its removal. As of this month (September 2025) there's a new community project [1,2] to revive aarch64_be. Jens Reidel (CC'd) and I are involved in it. We've been fixing several aarch64_be-related bugs, but mostly[3] in userspace, because the kernel support is pretty solid. So, just so it doesn't go unmentioned, there is interest in keeping big-endian ARM64 alive. Best regards, J. Neusch=C3=A4fer [1]: https://aarch64.be/ (binary packages) [2]: https://codeberg.org/neuschaefer/porting/src/branch/main/aarch64_be.m= d (status and documentation) [3]: https://lore.kernel.org/lkml/20250726235646.254730-1-adrian@mainlinin= g.org/