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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 240C0C3DA4A for ; Thu, 22 Aug 2024 08:59:08 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 7DF996B0186; Thu, 22 Aug 2024 04:59:08 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 768396B028C; Thu, 22 Aug 2024 04:59:08 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5E1F96B028D; Thu, 22 Aug 2024 04:59:08 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 3A16F6B0186 for ; Thu, 22 Aug 2024 04:59:08 -0400 (EDT) Received: from smtpin23.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id D85784144C for ; Thu, 22 Aug 2024 08:59:07 +0000 (UTC) X-FDA: 82479281934.23.FEE484B Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by imf20.hostedemail.com (Postfix) with ESMTP id 4CD4D1C001E for ; Thu, 22 Aug 2024 08:59:05 +0000 (UTC) Authentication-Results: imf20.hostedemail.com; dkim=none; dmarc=fail reason="SPF not aligned (relaxed), No valid DKIM" header.from=arm.com (policy=none); spf=pass (imf20.hostedemail.com: domain of cmarinas@kernel.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=cmarinas@kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1724317079; a=rsa-sha256; cv=none; b=fPGjQLJ29ESYeej96Up0TDHgjmvEwcStzBEb3Wiio7zxBcY1dTL09pIJS8eVpJ816PrvFg 8uTuc+noA1eqzPBERMoXlOV/rFaC3FovuhxuwNfX7LNIT7lJ5XVcAJFlNGdNTUpDCC/3hn hjCX1IbMukp6i+9w7Qa5KOvHSDRyZAQ= ARC-Authentication-Results: i=1; imf20.hostedemail.com; dkim=none; dmarc=fail reason="SPF not aligned (relaxed), No valid DKIM" header.from=arm.com (policy=none); spf=pass (imf20.hostedemail.com: domain of cmarinas@kernel.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=cmarinas@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1724317079; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=EFPwMWbZsxk21i+em6o1+8x08KObu0/8/gmBjEg4W5I=; b=XlnUDBh60E+zPR4sEIqEs6WZFIveWQ0pIKlgC4DJ5L51EZ33cbp23hpeAdtQEm2XlETmvx kIpULwoIT86L8OcwHgk+z1EIixHpcjLk2SeKs552g7kPZbP1Yc8oFB/9/BB15TpD3HkLsX ERpRdCM9odsEypCX0crayEiE/iCM3BY= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id 1E17E60FE8; Thu, 22 Aug 2024 08:59:04 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 35801C4AF0B; Thu, 22 Aug 2024 08:58:58 +0000 (UTC) Date: Thu, 22 Aug 2024 09:58:55 +0100 From: Catalin Marinas To: Mark Brown Cc: Will Deacon , Jonathan Corbet , Andrew Morton , Marc Zyngier , Oliver Upton , James Morse , Suzuki K Poulose , Arnd Bergmann , Oleg Nesterov , Eric Biederman , Shuah Khan , "Rick P. Edgecombe" , Deepak Gupta , Ard Biesheuvel , Szabolcs Nagy , Kees Cook , "H.J. Lu" , Paul Walmsley , Palmer Dabbelt , Albert Ou , Florian Weimer , Christian Brauner , Thiago Jung Bauermann , Ross Burton , Yury Khrustalev , Wilco Dijkstra , linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, kvmarm@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org Subject: Re: [PATCH v11 05/39] arm64: Document boot requirements for Guarded Control Stacks Message-ID: References: <20240822-arm64-gcs-v11-0-41b81947ecb5@kernel.org> <20240822-arm64-gcs-v11-5-41b81947ecb5@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240822-arm64-gcs-v11-5-41b81947ecb5@kernel.org> X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 4CD4D1C001E X-Stat-Signature: xfosrrp3nf3t8n9zrp9g71riocwioq7y X-Rspam-User: X-HE-Tag: 1724317145-837417 X-HE-Meta: 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 MMW08fDy 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Aug 22, 2024 at 02:15:08AM +0100, Mark Brown wrote: > FEAT_GCS introduces a number of new system registers, we require that > access to these registers is not trapped when we identify that the feature > is present. There is also a HCRX_EL2 control to make GCS operations > functional. > > Since if GCS is enabled any function call instruction will cause a fault > we also require that the feature be specifically disabled, existing > kernels implicitly have this requirement and especially given that the > MMU must be disabled it is difficult to see a situation where leaving > GCS enabled would be reasonable. > > Reviewed-by: Thiago Jung Bauermann > Signed-off-by: Mark Brown Reviewed-by: Catalin Marinas