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 968F2C3DA4A for ; Tue, 20 Aug 2024 17:30:19 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 1DF596B008C; Tue, 20 Aug 2024 13:30:19 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 18EA76B0092; Tue, 20 Aug 2024 13:30:19 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 07DB06B0095; Tue, 20 Aug 2024 13:30:19 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id DD3AF6B008C for ; Tue, 20 Aug 2024 13:30:18 -0400 (EDT) Received: from smtpin28.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id 5B91D1403FE for ; Tue, 20 Aug 2024 17:30:18 +0000 (UTC) X-FDA: 82473312516.28.1A2E454 Received: from nyc.source.kernel.org (nyc.source.kernel.org [147.75.193.91]) by imf02.hostedemail.com (Postfix) with ESMTP id A6AA78001C for ; Tue, 20 Aug 2024 17:30:16 +0000 (UTC) Authentication-Results: imf02.hostedemail.com; dkim=none; dmarc=fail reason="SPF not aligned (relaxed), No valid DKIM" header.from=arm.com (policy=none); spf=pass (imf02.hostedemail.com: domain of cmarinas@kernel.org designates 147.75.193.91 as permitted sender) smtp.mailfrom=cmarinas@kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1724175000; a=rsa-sha256; cv=none; b=uKwnA2bKaLxK84dXXdYfINH5fcPtdOeIRDi9KViB2rPNO2EMrkbEryN6m/xAajKaAm9WHH dVvXi1CaVuAfFoTAhfw+Om9YJmehSu9evjIY5HLrsmNOJhCn4eRf5kiAZjj/5V1xQp7C8k hz1ow+GPF1/A0k/zm4N51G771CTRzlg= ARC-Authentication-Results: i=1; imf02.hostedemail.com; dkim=none; dmarc=fail reason="SPF not aligned (relaxed), No valid DKIM" header.from=arm.com (policy=none); spf=pass (imf02.hostedemail.com: domain of cmarinas@kernel.org designates 147.75.193.91 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=1724175000; 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=qAyv2Bl+Vr7prkxFYvdrSiCl6sP6gvq9wg5hRiRDoM0=; b=1P5ovvBMxOyrDIDVBi3Vv3xu1gMk0rDzfRAvrk4P2ByMxqNvqKJTLd0LurL+Dnw3pW2JmO vO7mNDFUw9vKVIpSFewD7CVgFRODwxlrIiUmlxX0qDO0U0XGwehR2/1FlXXnQAJARtLwJa j1HSzg0/NTHZeWL6jEyAvhs/zn21a0M= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by nyc.source.kernel.org (Postfix) with ESMTP id 3F62EA402A2; Tue, 20 Aug 2024 13:30:09 -0400 (EDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id EFB55C4AF52; Tue, 20 Aug 2024 17:30:09 +0000 (UTC) Date: Tue, 20 Aug 2024 18:30:07 +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 , 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 v10 13/40] arm64/mm: Map pages for guarded control stack Message-ID: References: <20240801-arm64-gcs-v10-0-699e2bd2190b@kernel.org> <20240801-arm64-gcs-v10-13-699e2bd2190b@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspam-User: X-Rspamd-Queue-Id: A6AA78001C X-Rspamd-Server: rspam01 X-Stat-Signature: aeyiaxx89kcrp9ttsgbr813w6bac5c6t X-HE-Tag: 1724175016-453298 X-HE-Meta: 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 9YHnmE42 OzpBYrn9n6wgocIP2NU8HOH5jj7nM+ynt4x8uDNZ3mfo1zdt/GGPE+1hj8e/DBQgtHmehDPXiN6X2ObMsin2A+z0SlWdkUzHONLXXpSZ4OFRBRTiyUnZR5AF6QcNVimTTzp1jw/CJXPKtbFgLCS6iNYqiE1m0IHGEdrSyOSIV8bx2mLuK9uuF4gWN2tVK1Dlt3tcJgbtF/n4USZCLSFArhjp60eHW0LGYA4wAPFg8fYNMTU2JIKiCrxf5MO+eFK4YVYLupsMfc2stbQa7O8zk76rkmTOxPgR0ZYujfGr9JvO7y0HIb6un/m+oYhy//DGQ3et8uvwIOYFI+Mrv4NgiieqytP3s+mMw8Cql7o8PafrHX90C/+dvnocj0UZGJrG5P2Jqg5Yncz1Y8gwgJuGFXvb6WSOgDc01X/x4 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 Tue, Aug 20, 2024 at 04:28:21PM +0100, Mark Brown wrote: > On Tue, Aug 20, 2024 at 03:59:21PM +0100, Catalin Marinas wrote: > > On Mon, Aug 19, 2024 at 05:33:24PM +0100, Mark Brown wrote: > > > On Mon, Aug 19, 2024 at 10:10:36AM +0100, Catalin Marinas wrote: > > > > Is there any arch restriction with setting BTI and GCS? It doesn't make > > > > sense but curious if it matters. We block the exec permission anyway > > > > (unless the BTI pages moved to PIE as well, I don't remember). > > > > As you say BTI should be meaningless for a non-executable page like GCS, > > > I'm not aware of any way in which it matters. BTI is separate to PIE. > > > My thoughts were whether we can get rid of this hunk entirely by > > handling it in the core code. We'd allow BTI if one wants such useless > > combination but clear VM_MAYEXEC in the core code (and ignore VM_SHARED > > since you can't set it anyway). > > I have to admit that the BTI because I was shoving _EXEC in there rather > than because it specifically needed to be blocked. So change the check > for VM_SHARED to a VM_WARN_ON(), and leave the _EXEC check for now > pending the above core change? Yes, sounds good. -- Catalin