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 402D4C04FDF for ; Thu, 10 Aug 2023 17:20:37 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id AC4446B0071; Thu, 10 Aug 2023 13:20:36 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id A74286B0072; Thu, 10 Aug 2023 13:20:36 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 93BB86B0075; Thu, 10 Aug 2023 13:20:36 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id 8516A6B0071 for ; Thu, 10 Aug 2023 13:20:36 -0400 (EDT) Received: from smtpin04.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 4AF651601BA for ; Thu, 10 Aug 2023 17:20:32 +0000 (UTC) X-FDA: 81108859272.04.8D898C1 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by imf22.hostedemail.com (Postfix) with ESMTP id A8F5EC002E for ; Thu, 10 Aug 2023 17:20:34 +0000 (UTC) Authentication-Results: imf22.hostedemail.com; dkim=none; spf=pass (imf22.hostedemail.com: domain of cmarinas@kernel.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=cmarinas@kernel.org; dmarc=fail reason="SPF not aligned (relaxed), No valid DKIM" header.from=arm.com (policy=none) ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1691688034; 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=aXREsOcMtPBbbLD+GGJe4JjUkr/RymCbvjUKyuz/oHw=; b=mu2WidOt5b8tL1a8AXpznU0clQP7SAGezO4uguCVqjNpPpPdA21qqn+dcDGNdYwzjyWOgC G7jd/0VMYC20QWiBlP8SGXoVZgec5EHEj7GDx+3ycRv0UlMRspYzzmXCQeOL6ntpnSE4Vn 4buDBw6mUQKFHljTAtxWWn10vF2CTKc= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1691688034; a=rsa-sha256; cv=none; b=K+3qr+zZS/uUzbFiV+VO/9b2lEmnRmZcic94KzLLa7HXmvQkmZqQS86EA3exne+iV7UHCj w7zvdpQPN7xAfgXOtcmRva92IN2g1wEM2rylJJSFGzkrdbpUm6jlogD9FZj1B8YfZEkMHx A0FA2/Eck8HwZKpO4Ckv11Ycm/KgQJc= ARC-Authentication-Results: i=1; imf22.hostedemail.com; dkim=none; spf=pass (imf22.hostedemail.com: domain of cmarinas@kernel.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=cmarinas@kernel.org; dmarc=fail reason="SPF not aligned (relaxed), No valid DKIM" header.from=arm.com (policy=none) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 8BAE960C4E; Thu, 10 Aug 2023 17:20:33 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 45F14C433C8; Thu, 10 Aug 2023 17:20:28 +0000 (UTC) Date: Thu, 10 Aug 2023 18:20:25 +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 , Kees Cook , Shuah Khan , "Rick P. Edgecombe" , Deepak Gupta , Ard Biesheuvel , Szabolcs Nagy , "H.J. Lu" , Paul Walmsley , Palmer Dabbelt , Albert Ou , 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 v4 11/36] arm64/mm: Map pages for guarded control stack Message-ID: References: <20230807-arm64-gcs-v4-0-68cfa37f9069@kernel.org> <20230807-arm64-gcs-v4-11-68cfa37f9069@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230807-arm64-gcs-v4-11-68cfa37f9069@kernel.org> X-Rspamd-Queue-Id: A8F5EC002E X-Rspam-User: X-Rspamd-Server: rspam11 X-Stat-Signature: nfs8ep9uq1qpio9narkqe6j7fmd1cn79 X-HE-Tag: 1691688034-84324 X-HE-Meta: U2FsdGVkX1/e6ShCM+mT/zoVU8uDtH2kuchXfhEwFF3ci3iFEi8Figw4jd/v1CeH/2vrY7dya6cCKdKZO2FA1ehX6xbROsiz85Ir+A+eXiIPtw3W7V4K/CIj3Nln9YxngUOdcbACBUcfVDW2RPNQuq0ZU+GePZoFMLmLX9UpozJgQNlNdphNO8jw6PBwjVe8BvbQ5E3K4bM6iuBQs7d2jOlOSVtO+6Lr4cUUtxGDBTp6fJ0tkC+asxxk6/IshAwFCmMaZQTEVBgnvMJhKdJFMjggiKdHjllix1H0d4udrSRbrFYBUyeUR8PR3R1aAfIu95nHBzGvAUwqg0y7Lr+5ou6uvudo7vBv7en0K5yigPZAv/LPPmOiO62rHQKOpGfTb01sU5hM/3LWjPU62/CQM3tBToZYEaDaQleBcY0Ql/OlZKe4qhyTurG1F9diL0keRg7djlVKr5+/pSajZifsfWn6O2/6y7lRA6L9Gt3T+axNKbEYJUrZnpgCQxijJR8LnelIXmv0C/3HHiz2FFxWqkRkuf2t0KeBNjztHBDkQXxZ/ypeKYEXh8i7dUTXGn66KALfnjyrs/WgXBJT05gABa+OI2ugxGNY5+tXjQXjGrB9Fe37p5f0DA2R1qqkqQyI980AWdFQOR636AFjlUbKFILbnKW8uKIbLoOyfwsxb2Okrat8HEYt03zRIhaQ+JXbPkcHQZLPliIU3kuhAHF3LgDt3lVTFcrS5aMQ8VxqjfLxeaEjV5qR23u4O/nuimia1nonSdClFfDHowZMgjjV85ydDW1nyojKR3y7Cn8tvEs+UoX1ixaoa361aB1VfQ2sNh1kfdZFAxpvwgxsYoxeCZyhRafMe0gcCs+O352eG67zNyfIwH1SpoFtU1e4OuCehu/2Mr6+0PmYfe5ru+OssEzlWh3p4QTn4vAS9VNQgVG+VdDc0V0u7L1h5W4g8jvml2NQdd1cnHjFgW8hPc+ qrUh+Avu OxQjAUEBRJWHM8pGrYyZCmlOMnNcVGbSM3pL7+aE3bA8DpqBj91bEUE8lcTwcTMD6L/pIx0QpubNF2wxA9bjfd2/pgjAocF2hUadCnWWktTltlKnxh+aFZhx2p4KMu+fZyYTDO4+Bw/R8w4CyJHR+NJaCsJ1jGeLqRTkAJUaIQh+oCUgYvrXdBQaysOSpH4HOHX4OJNcpIPwmREhppHou+9zRueCm/BcmNEWzrFXL+7d/iitN8EvSA5kWsCTpj4rId/ePMfUfb0YuLbi8BZG7wGia5cv3D3ljVUj12XthrfoDMgO5MMmis6c78WxrfP/6XuBAHD+aBT1pIu2jFH2ZbERqwksFxcxuVh7SrUtP2jXILlFlEVVfMHj0vj+N/sknCDICbXh5a/6RCtBiw4pudduwwd1noNPhrH4x+2BnJagnJnx+jiYN0BZCL/7BFPdngY1yByysU8XH8lYPH/iT5OdZuE53N8WTXhvE+wLYI7yPhek= 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: On Mon, Aug 07, 2023 at 11:00:16PM +0100, Mark Brown wrote: > diff --git a/arch/arm64/mm/mmap.c b/arch/arm64/mm/mmap.c > index 8f5b7ce857ed..8f40198cd44e 100644 > --- a/arch/arm64/mm/mmap.c > +++ b/arch/arm64/mm/mmap.c > @@ -79,8 +79,18 @@ arch_initcall(adjust_protection_map); > > pgprot_t vm_get_page_prot(unsigned long vm_flags) > { > - pteval_t prot = pgprot_val(protection_map[vm_flags & > + pteval_t prot; > + > + /* If this is a GCS then only interpret VM_WRITE. */ > + if (system_supports_gcs() && (vm_flags & VM_SHADOW_STACK)) { > + if (vm_flags & VM_WRITE) > + prot = _PAGE_GCS; > + else > + prot = _PAGE_GCS_RO; > + } else { > + prot = pgprot_val(protection_map[vm_flags & > (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]); > + } > > if (vm_flags & VM_ARM64_BTI) > prot |= PTE_GP; Some combinations here don't make sense like GCS + exec or BTI. I think the code above (correctly) ignores exec but it still sets PTE_GP if BTI (the architecture may allow this but you can't execute from the GCS page anyway). I haven't checked the x86 patches to see when VM_SHADOW_STACK is set but if there's no additional check at a higher level, we should add something to arch_validate_flags(), assuming it's called on those paths. -- Catalin