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 65687C433F5 for ; Fri, 22 Apr 2022 06:04:39 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id E96846B0072; Fri, 22 Apr 2022 02:04:38 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id E457E6B0073; Fri, 22 Apr 2022 02:04:38 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D0D646B0074; Fri, 22 Apr 2022 02:04:38 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay.hostedemail.com [64.99.140.27]) by kanga.kvack.org (Postfix) with ESMTP id C32F76B0072 for ; Fri, 22 Apr 2022 02:04:38 -0400 (EDT) Received: from smtpin15.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 83ED260604 for ; Fri, 22 Apr 2022 06:04:38 +0000 (UTC) X-FDA: 79383475836.15.05ACD4B Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf25.hostedemail.com (Postfix) with ESMTP id 04C4BA0002 for ; Fri, 22 Apr 2022 06:04:33 +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 C4B1D1576; Thu, 21 Apr 2022 23:04:36 -0700 (PDT) Received: from [10.163.40.48] (unknown [10.163.40.48]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 595F83F5A1; Thu, 21 Apr 2022 23:04:27 -0700 (PDT) Message-ID: <7fc56f41-a3c2-76be-7a20-dda392f3c4fc@arm.com> Date: Fri, 22 Apr 2022 11:35:13 +0530 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.5.0 Subject: Re: [PATCH -next v5 3/5] mm: page_table_check: add hooks to public helpers Content-Language: en-US To: Tong Tiangen , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Pasha Tatashin , Andrew Morton , Catalin Marinas , Will Deacon , Paul Walmsley , Palmer Dabbelt , Albert Ou Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linux-riscv@lists.infradead.org, Kefeng Wang , Guohanjun References: <20220421082042.1167967-1-tongtiangen@huawei.com> <20220421082042.1167967-4-tongtiangen@huawei.com> From: Anshuman Khandual In-Reply-To: <20220421082042.1167967-4-tongtiangen@huawei.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 04C4BA0002 X-Rspam-User: Authentication-Results: imf25.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=arm.com; spf=pass (imf25.hostedemail.com: domain of anshuman.khandual@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=anshuman.khandual@arm.com X-Stat-Signature: 1mufcro1mfdxbntie85yrgmgzocze6jt X-HE-Tag: 1650607473-842588 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 4/21/22 13:50, Tong Tiangen wrote: > Move ptep_clear() to the include/linux/pgtable.h and add page table check > relate hooks to some helpers, it's prepare for support page table check > feature on new architecture. Could instrumenting generic page table helpers (fallback instances when its corresponding __HAVE_ARCH_XXX is not defined on the platform), might add all the page table check hooks into paths on platforms which have not subscribed ARCH_SUPPORTS_PAGE_TABLE_CHECK in the first place ? Although these looks have !CONFIG_PAGE_TABLE_CHECK fallback stubs in the header, hence a build problem gets avoided. > > Signed-off-by: Tong Tiangen > Acked-by: Pasha Tatashin > --- > arch/x86/include/asm/pgtable.h | 10 ---------- > include/linux/pgtable.h | 26 ++++++++++++++++++-------- > 2 files changed, 18 insertions(+), 18 deletions(-) > > diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h > index 564abe42b0f7..51cd39858f81 100644 > --- a/arch/x86/include/asm/pgtable.h > +++ b/arch/x86/include/asm/pgtable.h > @@ -1073,16 +1073,6 @@ static inline pte_t ptep_get_and_clear_full(struct mm_struct *mm, > return pte; > } > > -#define __HAVE_ARCH_PTEP_CLEAR AFICS X86 is the only platform subscribing __HAVE_ARCH_PTEP_CLEAR. Hence if this is getting dropped for generic ptep_clear(), then no need to add back #ifnded __HAVE_ARCH_PTEP_CLEAR construct. Generic ptep_clear() is the only definition for all platforms ? Also if this patch is trying to drop off __HAVE_ARCH_PTEP_CLEAR along with other page table check related changes, it needs to be done via a separate patch instead. > -static inline void ptep_clear(struct mm_struct *mm, unsigned long addr, > - pte_t *ptep) > -{ > - if (IS_ENABLED(CONFIG_PAGE_TABLE_CHECK)) > - ptep_get_and_clear(mm, addr, ptep); > - else > - pte_clear(mm, addr, ptep); > -} > - > #define __HAVE_ARCH_PTEP_SET_WRPROTECT > static inline void ptep_set_wrprotect(struct mm_struct *mm, > unsigned long addr, pte_t *ptep) > diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h > index 49ab8ee2d6d7..10d2d91edf20 100644 > --- a/include/linux/pgtable.h > +++ b/include/linux/pgtable.h > @@ -12,6 +12,7 @@ > #include > #include > #include > +#include > > #if 5 - defined(__PAGETABLE_P4D_FOLDED) - defined(__PAGETABLE_PUD_FOLDED) - \ > defined(__PAGETABLE_PMD_FOLDED) != CONFIG_PGTABLE_LEVELS > @@ -272,14 +273,6 @@ static inline bool arch_has_hw_pte_young(void) > } > #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, > @@ -287,10 +280,22 @@ static inline pte_t ptep_get_and_clear(struct mm_struct *mm, > { > pte_t pte = *ptep; > pte_clear(mm, address, ptep); > + page_table_check_pte_clear(mm, address, pte); > return pte; > } > #endif > > +#ifndef __HAVE_ARCH_PTEP_CLEAR > +static inline void ptep_clear(struct mm_struct *mm, unsigned long addr, > + pte_t *ptep) > +{ > + if (IS_ENABLED(CONFIG_PAGE_TABLE_CHECK)) > + ptep_get_and_clear(mm, addr, ptep); > + else > + pte_clear(mm, addr, ptep); Could not this be reworked to avoid IS_ENABLED() ? This is confusing. If the page table hooks can be added to all potential page table paths via generic helpers, irrespective of CONFIG_PAGE_TABLE_CHECK option, there is no rationale for doing a IS_ENABLED() check here. > +} > +#endif > + > #ifndef __HAVE_ARCH_PTEP_GET > static inline pte_t ptep_get(pte_t *ptep) > { > @@ -360,7 +365,10 @@ static inline pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm, > pmd_t *pmdp) > { > pmd_t pmd = *pmdp; > + > pmd_clear(pmdp); > + page_table_check_pmd_clear(mm, address, pmd); > + > return pmd; > } > #endif /* __HAVE_ARCH_PMDP_HUGE_GET_AND_CLEAR */ > @@ -372,6 +380,8 @@ static inline pud_t pudp_huge_get_and_clear(struct mm_struct *mm, > pud_t pud = *pudp; > > pud_clear(pudp); > + page_table_check_pud_clear(mm, address, pud); > + > return pud; > } > #endif /* __HAVE_ARCH_PUDP_HUGE_GET_AND_CLEAR */