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 1A242CAC59A for ; Fri, 19 Sep 2025 18:41:02 +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:Content-Transfer-Encoding: MIME-Version:Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-Type: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References:List-Owner; bh=vgLTYHWYvFS6X1gJg4qSeHHQhl7ZBlr3FtTxte5x4t4=; b=U95s0KwyTp3QTeywrzWCc2apaI XuKMnMg0F2YlP++wB2HqeMFzlp4IuLz9pjUJy+nY+D8vTD+bBqN6whaRkKVS6xXTH6GLRwVjVLgQD PFz8K5opAo20LmUu/t4BJ68ga78K02L48SLHQa/VHSN73oV8hcCmdnhpxyjl4a+soBoaim1yGTwp4 hhw2bksMXZZmnVwpufMGHl0R/pMF1xrV6bkwi37FMdMtva5t204xLaiF52j/qQ2ru8KZ8S0hEloNx k7KivnQx6eHKv/PpG/f+vHlSd5z3v7BAnLIWlPQv0KeNFOp+5rgfVVmW3SW0dIEuNnN8B7R8zWw7B 1ur05wQQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uzg2S-00000003nMr-0TLD; Fri, 19 Sep 2025 18:40:56 +0000 Received: from tor.source.kernel.org ([2600:3c04:e001:324:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1uzg2Q-00000003nMi-43j5 for linux-arm-kernel@lists.infradead.org; Fri, 19 Sep 2025 18:40:55 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id 0C43F60140; Fri, 19 Sep 2025 18:40:54 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CD823C4CEF0; Fri, 19 Sep 2025 18:40:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1758307253; bh=FQnOFM1F0itW/iszcCGggYVZvZGYm+S4YRJE97YXAuM=; h=From:To:Cc:Subject:Date:From; b=hFvbuftl+RX1FitUodWKdQJVkUZeDhWzfgQYZqXBH0T/hjJTcJVF/LS3q9L3Orj+V 2xCaZyeA3RwptHtIUvMvJK6crFzQ6md+no9slpm8Q/PrmhYZzP7YS/3qsOvrbKZl0N z9ODS3IPcXWpaFAWnqlIBEgUzX7PDRDuWnp3Yhn0aGe2Juz8sqRSS20dk/7zBiygiE UuXn790VKC3dL9Qh0xMIaFp1HVz40MqXOc7ACXsLff26x+m6Ux7U08HyiQ0SMzZf95 9fWviNCcVnP0hjkHuYF5eTsymz9QxfWJo1rFF+NioNZd1jdPXVdF0ae2qH/cjYryU5 uHqF+oXU2ZzfA== From: Will Deacon To: linux-arm-kernel@lists.infradead.org Cc: Will Deacon , Catalin Marinas , Marc Zyngier , Ard Biesheuvel , Arnd Bergmann , Hanjun Guo , Jonathan Cameron , Guenter Roeck Subject: [PATCH] arm64: Kconfig: Make CPU_BIG_ENDIAN depend on BROKEN Date: Fri, 19 Sep 2025 19:40:25 +0100 Message-Id: <20250919184025.15416-1-will@kernel.org> X-Mailer: git-send-email 2.39.5 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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 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. 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. Make CPU_BIG_ENDIAN depend on BROKEN as an initial deprecation step towards its removal. Cc: Catalin Marinas Cc: Marc Zyngier Cc: Ard Biesheuvel Cc: Arnd Bergmann Cc: Hanjun Guo Cc: Jonathan Cameron Cc: Guenter Roeck Link: https://lore.kernel.org/linux-arm-kernel/73701e9f-bee1-7ae8-2277-7a3576171cd4@huawei.com/ [1] Signed-off-by: Will Deacon --- Cc'ing Guenter as a heads-up in case he needs to turn down his testing to avoid this causing a false regression report. Cc'ing Hanjun and Jonathan for clarity on the telecommunication situation. arch/arm64/Kconfig | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index e9bbfacc35a6..5ac670d41604 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -1493,7 +1493,7 @@ choice config CPU_BIG_ENDIAN bool "Build big-endian kernel" # https://github.com/llvm/llvm-project/commit/1379b150991f70a5782e9a143c2ba5308da1161c - depends on AS_IS_GNU || AS_VERSION >= 150000 + depends on (AS_IS_GNU || AS_VERSION >= 150000) && BROKEN help Say Y if you plan on running a kernel with a big-endian userspace. -- 2.51.0.470.ga7dc726c21-goog