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 5F886C433EF for ; Thu, 17 Mar 2022 19:00:18 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 97E168D0002; Thu, 17 Mar 2022 15:00:17 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 92D388D0001; Thu, 17 Mar 2022 15:00:17 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7F4B08D0002; Thu, 17 Mar 2022 15:00:17 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay.hostedemail.com [64.99.140.28]) by kanga.kvack.org (Postfix) with ESMTP id 6E1728D0001 for ; Thu, 17 Mar 2022 15:00:17 -0400 (EDT) Received: from smtpin08.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay12.hostedemail.com (Postfix) with ESMTP id 337A2121D69 for ; Thu, 17 Mar 2022 19:00:17 +0000 (UTC) X-FDA: 79254793674.08.2CC533A Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by imf29.hostedemail.com (Postfix) with ESMTP id 86739120021 for ; Thu, 17 Mar 2022 19:00:16 +0000 (UTC) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 84A4AB81F79; Thu, 17 Mar 2022 19:00:14 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C4176C340E9; Thu, 17 Mar 2022 19:00:08 +0000 (UTC) Date: Thu, 17 Mar 2022 19:00:04 +0000 From: Catalin Marinas To: Tong Tiangen Cc: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Pasha Tatashin , Andrew Morton , Will Deacon , Paul Walmsley , Palmer Dabbelt , Palmer Dabbelt , Albert Ou , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linux-riscv@lists.infradead.org Subject: Re: [PATCH -next 3/4] arm64: mm: add support for page table check Message-ID: References: <20220317141203.3646253-1-tongtiangen@huawei.com> <20220317141203.3646253-4-tongtiangen@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220317141203.3646253-4-tongtiangen@huawei.com> X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 86739120021 X-Stat-Signature: qsgzzf6hbz5asd76tkyaq3jb71ncuq9r Authentication-Results: imf29.hostedemail.com; dkim=none; dmarc=fail reason="SPF not aligned (relaxed), No valid DKIM" header.from=arm.com (policy=none); spf=pass (imf29.hostedemail.com: domain of cmarinas@kernel.org designates 145.40.68.75 as permitted sender) smtp.mailfrom=cmarinas@kernel.org X-Rspam-User: X-HE-Tag: 1647543616-858411 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 Thu, Mar 17, 2022 at 02:12:02PM +0000, Tong Tiangen wrote: > @@ -628,6 +647,25 @@ static inline unsigned long pmd_page_vaddr(pmd_t pmd) > #define pud_leaf(pud) pud_sect(pud) > #define pud_valid(pud) pte_valid(pud_pte(pud)) > > +#ifdef CONFIG_PAGE_TABLE_CHECK > +static inline bool pte_user_accessible_page(pte_t pte) > +{ > + return (pte_val(pte) & PTE_VALID) && (pte_val(pte) & PTE_USER); > +} There is another class of user mappings, execute-only, that have both PTE_USER and PTE_UXN cleared. So this logic should be: pte_valid(pte) && (pte_user(pte) || pte_user_exec(pte)) with pte_user() as: #define pte_user(pte) (!!(pte_val(pte) & PTE_USER)) Do we care about PROT_NONE mappings here? They have the valid bit cleared but pte_present() is true. > +static inline bool pmd_user_accessible_page(pmd_t pmd) > +{ > + return pmd_leaf(pmd) && (pmd_val(pmd) & PTE_VALID) && > + (pmd_val(pmd) & PTE_USER); > +} pmd_leaf() implies valid, so you can skip it if that's the aim. Similar comment to the pte variant on execute-only and PROT_NONE mappings. -- Catalin