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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0374BC43219 for ; Tue, 23 Nov 2021 21:48:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239461AbhKWVvw (ORCPT ); Tue, 23 Nov 2021 16:51:52 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52536 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238317AbhKWVv2 (ORCPT ); Tue, 23 Nov 2021 16:51:28 -0500 Received: from mail-qk1-x735.google.com (mail-qk1-x735.google.com [IPv6:2607:f8b0:4864:20::735]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7BE1EC06173E for ; Tue, 23 Nov 2021 13:48:19 -0800 (PST) Received: by mail-qk1-x735.google.com with SMTP id t6so676017qkg.1 for ; Tue, 23 Nov 2021 13:48:19 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=soleen.com; s=google; h=from:to:subject:date:message-id:in-reply-to:references:mime-version :content-transfer-encoding; bh=IVq3xL/pGZ8u0z7x5W1W5jQgsvzAwjupWoCmB038rW4=; b=G1yf+kXdQSCQD2XX4vpaXjnLHMUnVSvr8wghraZeZ54IeI3vABq00MYhRLvn7B0BQj WFnWrl3P4ameNfuBol/K0SMcyQjGHxvbqMW5sxYkW9pBjZzyGbdX31YKs4VquaKaZ6kE atxbCrZJ/yH6iW0bSfSMepvDf2oPgSogWZ437zF6n9hr2miP+UXMJGx5bD3m4tN538Nn QMv5b50OrO2q5Cz0el22udQqQwwJ1Jvi3AyycvyRdbeaQ1ZKmrUyYELWFRw4jgKkX/22 bvihqUrzRtt+eAVAxIQBYxdTmK85MlBLafz7BfQZvqfuWzsb4RdomknG2N4TZOoBxF27 N7SQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=IVq3xL/pGZ8u0z7x5W1W5jQgsvzAwjupWoCmB038rW4=; b=XgJFraitZ6XXNFVEB0BXO04oGw4zocF4M5u4185cOcrkxRUxtWGxO/OwFXMErVK/1C qzd0/HZ7vUK9zSqo0Klw0hMIfY3Cgru67xXtu0gCjTYqKMI1tT2LykTmj/R328ahHTE4 IoAtrQen4dsANLMtShWPcNX74kxYWj6rNHgaSpvI8s1F8nunlo28zryYkVA3fP5mFI1C psI+bQpdp0ZIiirMg21/aBWCkOGlRpnGb/0MIJt/15CuR4j2HxUH5G3ncN0sRvZQRemm W9bmw1auPEJLyRZ1qxz0aVM1pz6tsc/yBvm0UwRfJpGVT5aOaKkQ7fd1GC5bYvCA5dbi 8Fwg== X-Gm-Message-State: AOAM531J0rNfrOlRgWNlBONpxrAPiVRJlT2cx3Zzf2Fy4UPm+WUDdNoG FkU/fp3rfQ3u9zp0PXRMGr7PcQ== X-Google-Smtp-Source: ABdhPJxa4rkJ3dDwmQINdVy3b0iHLUCHPrStd8iakB8X+JnpdpcRlZN05HXBIWWcP0xIf6ILqJywfw== X-Received: by 2002:a37:9f84:: with SMTP id i126mr620199qke.249.1637704098675; Tue, 23 Nov 2021 13:48:18 -0800 (PST) Received: from soleen.c.googlers.com.com (189.216.85.34.bc.googleusercontent.com. [34.85.216.189]) by smtp.gmail.com with ESMTPSA id i11sm7356912qko.116.2021.11.23.13.48.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 23 Nov 2021 13:48:18 -0800 (PST) From: Pasha Tatashin To: pasha.tatashin@soleen.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-doc@vger.kernel.org, akpm@linux-foundation.org, rientjes@google.com, pjt@google.com, weixugc@google.com, gthelen@google.com, mingo@redhat.com, corbet@lwn.net, will@kernel.org, rppt@kernel.org, keescook@chromium.org, tglx@linutronix.de, peterz@infradead.org, masahiroy@kernel.org, samitolvanen@google.com, dave.hansen@linux.intel.com, x86@kernel.org, frederic@kernel.org, hpa@zytor.com, aneesh.kumar@linux.ibm.com Subject: [PATCH 1/3] mm: ptep_clear() page table helper Date: Tue, 23 Nov 2021 21:48:12 +0000 Message-Id: <20211123214814.3756047-2-pasha.tatashin@soleen.com> X-Mailer: git-send-email 2.34.0.rc2.393.gf8c9666880-goog In-Reply-To: <20211123214814.3756047-1-pasha.tatashin@soleen.com> References: <20211123214814.3756047-1-pasha.tatashin@soleen.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org We have ptep_get_and_clear() and ptep_get_and_clear_full() helpers to clear PTE from user page tables, but there is no variant for simple clear of a present PTE from user page tables without using a low level pte_clear() which can be either native or para-virtualised. Add a new ptep_clear() that can be used in common code to clear PTEs from page table. We will need this call later in order to add a hook for page table check. Signed-off-by: Pasha Tatashin --- Documentation/vm/arch_pgtable_helpers.rst | 6 ++++-- include/linux/pgtable.h | 8 ++++++++ mm/debug_vm_pgtable.c | 2 +- mm/khugepaged.c | 12 ++---------- 4 files changed, 15 insertions(+), 13 deletions(-) diff --git a/Documentation/vm/arch_pgtable_helpers.rst b/Documentation/vm/arch_pgtable_helpers.rst index 552567d863b8..fbe06ec75370 100644 --- a/Documentation/vm/arch_pgtable_helpers.rst +++ b/Documentation/vm/arch_pgtable_helpers.rst @@ -66,9 +66,11 @@ PTE Page Table Helpers +---------------------------+--------------------------------------------------+ | pte_mknotpresent | Invalidates a mapped PTE | +---------------------------+--------------------------------------------------+ -| ptep_get_and_clear | Clears a PTE | +| ptep_clear | Clears a PTE | +---------------------------+--------------------------------------------------+ -| ptep_get_and_clear_full | Clears a PTE | +| ptep_get_and_clear | Clears and returns PTE | ++---------------------------+--------------------------------------------------+ +| ptep_get_and_clear_full | Clears and returns PTE (batched PTE unmap) | +---------------------------+--------------------------------------------------+ | ptep_test_and_clear_young | Clears young from a PTE | +---------------------------+--------------------------------------------------+ diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h index e24d2c992b11..bc8713a76e03 100644 --- a/include/linux/pgtable.h +++ b/include/linux/pgtable.h @@ -258,6 +258,14 @@ static inline int pmdp_clear_flush_young(struct vm_area_struct *vma, #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ #endif +#ifndef __HAVE_ARCH_PTEP_CLEAR +static inline void ptep_clear(struct mm_struct *mm, unsigned long addr, + pte_t *ptep) +{ + pte_clear(mm, addr, ptep); +} +#endif + #ifndef __HAVE_ARCH_PTEP_GET_AND_CLEAR static inline pte_t ptep_get_and_clear(struct mm_struct *mm, unsigned long address, diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c index 228e3954b90c..cd48a34c87a4 100644 --- a/mm/debug_vm_pgtable.c +++ b/mm/debug_vm_pgtable.c @@ -652,7 +652,7 @@ static void __init pte_clear_tests(struct pgtable_debug_args *args) set_pte_at(args->mm, args->vaddr, args->ptep, pte); flush_dcache_page(page); barrier(); - pte_clear(args->mm, args->vaddr, args->ptep); + ptep_clear(args->mm, args->vaddr, args->ptep); pte = ptep_get(args->ptep); WARN_ON(!pte_none(pte)); } diff --git a/mm/khugepaged.c b/mm/khugepaged.c index dd807261ed9f..c78242d15406 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -756,11 +756,7 @@ static void __collapse_huge_page_copy(pte_t *pte, struct page *page, * ptl mostly unnecessary. */ spin_lock(ptl); - /* - * paravirt calls inside pte_clear here are - * superfluous. - */ - pte_clear(vma->vm_mm, address, _pte); + ptep_clear(vma->vm_mm, address, _pte); spin_unlock(ptl); } } else { @@ -774,11 +770,7 @@ static void __collapse_huge_page_copy(pte_t *pte, struct page *page, * inside page_remove_rmap(). */ spin_lock(ptl); - /* - * paravirt calls inside pte_clear here are - * superfluous. - */ - pte_clear(vma->vm_mm, address, _pte); + ptep_clear(vma->vm_mm, address, _pte); page_remove_rmap(src_page, false); spin_unlock(ptl); free_page_and_swap_cache(src_page); -- 2.34.0.rc2.393.gf8c9666880-goog