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 C6CA0CAC5B9 for ; Tue, 30 Sep 2025 08:58:04 +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: Content-Type:MIME-Version:References:In-Reply-To:Subject:Cc:To:From: Message-ID:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=XxJiz/J2FK7S/+n19YR7tCBIc5UI/j/V8395bhf+H/Y=; b=W+ukLV8OV86tr4ZaMSqpw8ceMm 4S5Zf5503JWKRLers/3SEEj6iMxRTyqjWypu5+pbcSrZtjwNVcjxOhdCgmXrt47oUbedF8LEGWyEI kgx0s7mlOnml+Erk6AmFE/d92URCm1AIdnMQQ668WiOHfpMVLX60oDrdVsocDyODKXS9/IhvCHZ8J AbfkyJtbbvLEUJ0l1+85iMe8Lq22fm35MJyNwzSNjupbVAbnG3Li1fiJE0iGYmOKIgsyVBsrmsWwX XtXuOiVqMmEhdGwp7XDBnWzHCnLP4ftYSpv2bxOORkzAzHifaY6hD87kY0uRH+KE6tqY/mb3FlsX5 bF8Na3xA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1v3WBK-00000004iXE-3FQG; Tue, 30 Sep 2025 08:57:58 +0000 Received: from sea.source.kernel.org ([2600:3c0a:e001:78e:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1v3WBH-00000004iWt-325u for linux-arm-kernel@lists.infradead.org; Tue, 30 Sep 2025 08:57:57 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id 3CEFC44196; Tue, 30 Sep 2025 08:57:55 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 13A7AC4CEF0; Tue, 30 Sep 2025 08:57:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1759222675; bh=Fp5kb+GpqhyNFi1NcvelOWb2J6Zp9p9ezeUv7fp0BiQ=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=SAcOSeXutmJkKHHxK2aPM9yuZCcJe3pJ1ZrRE+5+WAFWAqqDcNKm8lQfqGNRorWic QpYg7rthAGa35cZQ03FGA2ahsIjbi0sEWAfHmOiqE2bHcE7upWTnnB5MsGeQJbiIKX UAzvIE2xkVH7VwRc/mJeDd1IC3NjaNg85ct8bEGH2M3x+rC+wwHqkypvPYJVCFAsXN D7wD1eVwnQp0BOsUcZfZZ9pZlzr+EfsO3rjNlRAg29vs8HXpVz4hOWLLgbDHCF7jjm GFAv67ZG35b+A1udIn5KdUOoJUfVhaF8sSAtckGuw2ADBj9jt148AkGVEzZGRQRNGg +VA/QvxW6u42Q== Received: from sofa.misterjones.org ([185.219.108.64] helo=goblin-girl.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.98.2) (envelope-from ) id 1v3WBE-0000000AUEc-37ht; Tue, 30 Sep 2025 08:57:52 +0000 Date: Tue, 30 Sep 2025 09:57:52 +0100 Message-ID: <86wm5gz59r.wl-maz@kernel.org> From: Marc Zyngier To: =?UTF-8?B?IkouIE5ldXNjaMOkZmVyIg==?= Cc: Catalin Marinas , Will Deacon , linux-arm-kernel@lists.infradead.org, Ard Biesheuvel , Arnd Bergmann , Hanjun Guo , Jonathan Cameron , Guenter Roeck , Jens Reidel Subject: Re: [PATCH] arm64: Kconfig: Make CPU_BIG_ENDIAN depend on BROKEN In-Reply-To: References: <20250919184025.15416-1-will@kernel.org> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/30.1 (aarch64-unknown-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: j.neuschaefer@gmx.net, catalin.marinas@arm.com, will@kernel.org, linux-arm-kernel@lists.infradead.org, ardb@kernel.org, arnd@arndb.de, guohanjun@huawei.com, Jonathan.Cameron@huawei.com, linux@roeck-us.net, adrian@mainlining.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250930_015756_042020_B1BEC8E5 X-CRM114-Status: GOOD ( 14.40 ) 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 Mon, 29 Sep 2025 21:16:33 +0100, "J. Neusch=C3=A4fer" wrote: >=20 > I understand the maintenance cost argument, and I'm fine with the > CONFIG_BROKEN dependency, even if it might be applied to features that > cause problems in the future (such as nested virt) =E2=80=94 it's easy to= work > around, and features can be fixed as needed. Not really. Cross-endianness support is completely incompatible with nested virt *by design*, and can't be worked around by SW. You'd need to introduce incompatible changes in the architecture to support this. Yes, this is a shame, but also a sign that architecture and implementations have moved on. M. --=20 Without deviation from the norm, progress is not possible.