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 X-Spam-Level: X-Spam-Status: No, score=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 275EAC64E7B for ; Tue, 1 Dec 2020 12:20:11 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 847E82080A for ; Tue, 1 Dec 2020 12:20:10 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 847E82080A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 145026B0072; Tue, 1 Dec 2020 07:20:10 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 0F5246B0073; Tue, 1 Dec 2020 07:20:10 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 0320E8D0001; Tue, 1 Dec 2020 07:20:09 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0075.hostedemail.com [216.40.44.75]) by kanga.kvack.org (Postfix) with ESMTP id E32866B0072 for ; Tue, 1 Dec 2020 07:20:09 -0500 (EST) Received: from smtpin20.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id A8F5C3636 for ; Tue, 1 Dec 2020 12:20:09 +0000 (UTC) X-FDA: 77544620538.20.face61_5c026f2273aa Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin20.hostedemail.com (Postfix) with ESMTP id 83C55180C0609 for ; Tue, 1 Dec 2020 12:20:09 +0000 (UTC) X-HE-Tag: face61_5c026f2273aa X-Filterd-Recvd-Size: 9071 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf28.hostedemail.com (Postfix) with ESMTP for ; Tue, 1 Dec 2020 12:20:08 +0000 (UTC) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 1EAF21063; Tue, 1 Dec 2020 04:20:08 -0800 (PST) Received: from p8cg001049571a15.arm.com (unknown [10.163.85.56]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 6C7813F718; Tue, 1 Dec 2020 04:20:02 -0800 (PST) From: Anshuman Khandual To: linux-mm@kvack.org, akpm@linux-foundation.org Cc: linux-kernel@vger.kernel.org, catalin.marinas@arm.com, steven.price@arm.com, christophe.leroy@csgroup.eu, gerald.schaefer@linux.ibm.com, vgupta@synopsys.com, paul.walmsley@sifive.com, Anshuman Khandual Subject: [PATCH V2 1/2] mm/debug_vm_pgtable/basic: Add validation for dirtiness after write protect Date: Tue, 1 Dec 2020 17:49:28 +0530 Message-Id: <1606825169-5229-2-git-send-email-anshuman.khandual@arm.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1606825169-5229-1-git-send-email-anshuman.khandual@arm.com> References: <1606825169-5229-1-git-send-email-anshuman.khandual@arm.com> 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: This adds validation tests for dirtiness after write protect conversion for each page table level. There are two new separate test types involved here. The first test ensures that a given page table entry does not become dirty after pxx_wrprotect(). This is important for platforms like arm64 which transfers and drops the hardware dirty bit (!PTE_RDONLY) to the software dirty bit while making it an write protected one. This test ensures that no fresh page table entry could be created with hardware dirty bit set. The second test ensures that a given page table entry always preserve the dirty information across pxx_wrprotect(). This adds two previously missing PUD level basic tests and while here fixes pxx_wrprotect() related typos in the documentation file. Cc: Andrew Morton Cc: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org Suggested-by: Catalin Marinas Signed-off-by: Anshuman Khandual --- Documentation/vm/arch_pgtable_helpers.rst | 8 ++--- mm/debug_vm_pgtable.c | 42 +++++++++++++++++++++++ 2 files changed, 46 insertions(+), 4 deletions(-) diff --git a/Documentation/vm/arch_pgtable_helpers.rst b/Documentation/vm/arch_pgtable_helpers.rst index f3591ee3aaa8..552567d863b8 100644 --- a/Documentation/vm/arch_pgtable_helpers.rst +++ b/Documentation/vm/arch_pgtable_helpers.rst @@ -50,7 +50,7 @@ PTE Page Table Helpers +---------------------------+--------------------------------------------------+ | pte_mkwrite | Creates a writable PTE | +---------------------------+--------------------------------------------------+ -| pte_mkwrprotect | Creates a write protected PTE | +| pte_wrprotect | Creates a write protected PTE | +---------------------------+--------------------------------------------------+ | pte_mkspecial | Creates a special PTE | +---------------------------+--------------------------------------------------+ @@ -120,7 +120,7 @@ PMD Page Table Helpers +---------------------------+--------------------------------------------------+ | pmd_mkwrite | Creates a writable PMD | +---------------------------+--------------------------------------------------+ -| pmd_mkwrprotect | Creates a write protected PMD | +| pmd_wrprotect | Creates a write protected PMD | +---------------------------+--------------------------------------------------+ | pmd_mkspecial | Creates a special PMD | +---------------------------+--------------------------------------------------+ @@ -186,7 +186,7 @@ PUD Page Table Helpers +---------------------------+--------------------------------------------------+ | pud_mkwrite | Creates a writable PUD | +---------------------------+--------------------------------------------------+ -| pud_mkwrprotect | Creates a write protected PUD | +| pud_wrprotect | Creates a write protected PUD | +---------------------------+--------------------------------------------------+ | pud_mkdevmap | Creates a ZONE_DEVICE mapped PUD | +---------------------------+--------------------------------------------------+ @@ -224,7 +224,7 @@ HugeTLB Page Table Helpers +---------------------------+--------------------------------------------------+ | huge_pte_mkwrite | Creates a writable HugeTLB | +---------------------------+--------------------------------------------------+ -| huge_pte_mkwrprotect | Creates a write protected HugeTLB | +| huge_pte_wrprotect | Creates a write protected HugeTLB | +---------------------------+--------------------------------------------------+ | huge_ptep_get_and_clear | Clears a HugeTLB | +---------------------------+--------------------------------------------------+ diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c index c05d9dcf7891..c6fffea54522 100644 --- a/mm/debug_vm_pgtable.c +++ b/mm/debug_vm_pgtable.c @@ -63,6 +63,17 @@ static void __init pte_basic_tests(unsigned long pfn, pgprot_t prot) pte_t pte = pfn_pte(pfn, prot); pr_debug("Validating PTE basic\n"); + + /* + * This test needs to execute right after the given page + * table entry is created with pfn_pte() to make sure that + * protection_map[idx] does not have the dirty bit enabled + * from the beginning. This is particularly important for + * platforms like arm64 where (!PTE_RDONLY) indicate dirty + * bit being set. + */ + WARN_ON(pte_dirty(pte_wrprotect(pte))); + WARN_ON(!pte_same(pte, pte)); WARN_ON(!pte_young(pte_mkyoung(pte_mkold(pte)))); WARN_ON(!pte_dirty(pte_mkdirty(pte_mkclean(pte)))); @@ -70,6 +81,8 @@ static void __init pte_basic_tests(unsigned long pfn, pgprot_t prot) WARN_ON(pte_young(pte_mkold(pte_mkyoung(pte)))); WARN_ON(pte_dirty(pte_mkclean(pte_mkdirty(pte)))); WARN_ON(pte_write(pte_wrprotect(pte_mkwrite(pte)))); + WARN_ON(pte_dirty(pte_wrprotect(pte_mkclean(pte)))); + WARN_ON(!pte_dirty(pte_wrprotect(pte_mkdirty(pte)))); } static void __init pte_advanced_tests(struct mm_struct *mm, @@ -137,6 +150,18 @@ static void __init pmd_basic_tests(unsigned long pfn, pgprot_t prot) return; pr_debug("Validating PMD basic\n"); + + /* + * This test needs to execute right after the given page + * table entry is created with pfn_pmd() to make sure that + * protection_map[idx] does not have the dirty bit enabled + * from the beginning. This is particularly important for + * platforms like arm64 where (!PTE_RDONLY) indicate dirty + * bit being set. + */ + WARN_ON(pmd_dirty(pmd_wrprotect(pmd))); + + WARN_ON(!pmd_same(pmd, pmd)); WARN_ON(!pmd_young(pmd_mkyoung(pmd_mkold(pmd)))); WARN_ON(!pmd_dirty(pmd_mkdirty(pmd_mkclean(pmd)))); @@ -144,6 +169,8 @@ static void __init pmd_basic_tests(unsigned long pfn, pgprot_t prot) WARN_ON(pmd_young(pmd_mkold(pmd_mkyoung(pmd)))); WARN_ON(pmd_dirty(pmd_mkclean(pmd_mkdirty(pmd)))); WARN_ON(pmd_write(pmd_wrprotect(pmd_mkwrite(pmd)))); + WARN_ON(pmd_dirty(pmd_wrprotect(pmd_mkclean(pmd)))); + WARN_ON(!pmd_dirty(pmd_wrprotect(pmd_mkdirty(pmd)))); /* * A huge page does not point to next level page table * entry. Hence this must qualify as pmd_bad(). @@ -257,11 +284,26 @@ static void __init pud_basic_tests(unsigned long pfn, pgprot_t prot) return; pr_debug("Validating PUD basic\n"); + + /* + * This test needs to execute right after the given page + * table entry is created with pfn_pud() to make sure that + * protection_map[idx] does not have the dirty bit enabled + * from the beginning. This is particularly important for + * platforms like arm64 where (!PTE_RDONLY) indicate dirty + * bit being set. + */ + WARN_ON(pud_dirty(pud_wrprotect(pud))); + WARN_ON(!pud_same(pud, pud)); WARN_ON(!pud_young(pud_mkyoung(pud_mkold(pud)))); + WARN_ON(!pud_dirty(pud_mkdirty(pud_mkclean(pud)))); + WARN_ON(pud_dirty(pud_mkclean(pud_mkdirty(pud)))); WARN_ON(!pud_write(pud_mkwrite(pud_wrprotect(pud)))); WARN_ON(pud_write(pud_wrprotect(pud_mkwrite(pud)))); WARN_ON(pud_young(pud_mkold(pud_mkyoung(pud)))); + WARN_ON(pud_dirty(pud_wrprotect(pud_mkclean(pud)))); + WARN_ON(!pud_dirty(pud_wrprotect(pud_mkdirty(pud)))); if (mm_pmd_folded(mm)) return; -- 2.20.1