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=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 D7CF8C5DF60 for ; Wed, 6 Nov 2019 03:05:52 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 198C521D7F for ; Wed, 6 Nov 2019 03:05:51 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 198C521D7F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 477BHd4yvWzF5BJ for ; Wed, 6 Nov 2019 14:05:49 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=arm.com (client-ip=217.140.110.172; helo=foss.arm.com; envelope-from=anshuman.khandual@arm.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=arm.com Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lists.ozlabs.org (Postfix) with ESMTP id 477BFN3JyszF1pB for ; Wed, 6 Nov 2019 14:03:49 +1100 (AEDT) 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 1394D30E; Tue, 5 Nov 2019 19:03:44 -0800 (PST) Received: from [192.168.225.149] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id EAE593F719; Tue, 5 Nov 2019 19:03:20 -0800 (PST) Subject: Re: [PATCH V8] mm/debug: Add tests validating architecture page table helpers To: Vineet Gupta , "linux-mm@kvack.org" , Andrew Morton References: <1572240562-23630-1-git-send-email-anshuman.khandual@arm.com>

From: Anshuman Khandual Message-ID: Date: Wed, 6 Nov 2019 08:33:52 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , "linux-ia64@vger.kernel.org" , "linux-sh@vger.kernel.org" , Peter Zijlstra , James Hogan , Heiko Carstens , Michal Hocko , Dave Hansen , Paul Mackerras , "sparclinux@vger.kernel.org" , Dan Williams , "linux-s390@vger.kernel.org" , Jason Gunthorpe , "x86@kernel.org" , Russell King - ARM Linux , Matthew Wilcox , Steven Price , Tetsuo Handa , Gerald Schaefer , "linux-snps-arc@lists.infradead.org" , "linux-arm-kernel@lists.infradead.org" , Ingo Molnar , Kees Cook , Masahiro Yamada , Mark Brown , "Kirill A . Shutemov" , Thomas Gleixner , Vlastimil Babka , Sri Krishna chowdary , Ard Biesheuvel , Greg Kroah-Hartman , "linux-mips@vger.kernel.org" , Ralf Baechle , "linux-kernel@vger.kernel.org" , Paul Burton , Mike Rapoport , Martin Schwidefsky , "linuxppc-dev@lists.ozlabs.org" , "David S. Miller" Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On 11/06/2019 04:00 AM, Vineet Gupta wrote: > Hi Anshuman, Hello Vineet, > > On 11/4/19 4:00 PM, Anshuman Khandual wrote: >> On 10/28/2019 10:59 AM, Anshuman Khandual wrote: >>> This adds tests which will validate architecture page table helpers and >>> other accessors in their compliance with expected generic MM semantics. >>> This will help various architectures in validating changes to existing >>> page table helpers or addition of new ones. >>> >>> This test covers basic page table entry transformations including but not >>> limited to old, young, dirty, clean, write, write protect etc at various >>> level along with populating intermediate entries with next page table page >>> and validating them. >>> >>> Test page table pages are allocated from system memory with required size >>> and alignments. The mapped pfns at page table levels are derived from a >>> real pfn representing a valid kernel text symbol. This test gets called >>> right after page_alloc_init_late(). >>> >>> This gets build and run when CONFIG_DEBUG_VM_PGTABLE is selected along with >>> CONFIG_VM_DEBUG. Architectures willing to subscribe this test also need to >>> select CONFIG_ARCH_HAS_DEBUG_VM_PGTABLE which for now is limited to x86 and >>> arm64. Going forward, other architectures too can enable this after fixing >>> build or runtime problems (if any) with their page table helpers. >>> >>> Folks interested in making sure that a given platform's page table helpers >>> conform to expected generic MM semantics should enable the above config >>> which will just trigger this test during boot. Any non conformity here will >>> be reported as an warning which would need to be fixed. This test will help >>> catch any changes to the agreed upon semantics expected from generic MM and >>> enable platforms to accommodate it thereafter. >>> > > I tried enabling this on ARC and ran into a build issue > > ../mm/debug_vm_pgtable.c: In function ‘pmd_basic_tests’: > ../mm/debug_vm_pgtable.c:73:14: error: implicit declaration of function ‘pfn_pmd’; > did you mean ‘pfn_pte’? [-Werror=implicit-function-declaration] > pmd_t pmd = pfn_pmd(pfn, prot); > ^~~~~~~ > > The reason being THP was not enabled (although ARC supports THP) - for the > combination below > CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE=y > # CONFIG_TRANSPARENT_HUGEPAGE is not set > > I think you need to use latter for guarding pmd_basic_tests() So the build complains that pfn_pmd() is not defined when the following config combination is in place. CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE=y CONFIG_TRANSPARENT_HUGEPAGE=n But should not pfn_pmd() be encapsulated inside HAVE_ARCH_TRANSPARENT_HUGEPAGE at the minimum (but I would say it should be available always, nonetheless) when the platform subscribes to THP irrespective of whether THP is enabled or not. I could see in the file (arch/arc/include/asm/pgtable.h) that fetching pfn_pmd() and all other basic PMD definitions is conditional on CONFIG_TRANSPARENT_HUGEPAGE. #ifdef CONFIG_TRANSPARENT_HUGEPAGE #include #endif IIUC, CONFIG_TRANSPARENT_HUGEPAGE should only encapsulate PMD page table helpers which are expected from generic THP code (pmd_trans_huge, pmdp_set_access_flags etc) but not the basic PMD helpers like pmd_pfn, pmd_mkyoung, pmd_mkdirty, pmd_mkclean etc. Hence wondering will it be possible to accommodate following code change on arc platform (not even compiled) in order to fix the problem ? diff --git a/arch/arc/include/asm/hugepage.h b/arch/arc/include/asm/hugepage.h index 9a74ce7..2ae15a8 100644 --- a/arch/arc/include/asm/hugepage.h +++ b/arch/arc/include/asm/hugepage.h @@ -36,11 +36,11 @@ static inline pmd_t pte_pmd(pte_t pte) #define pmd_dirty(pmd) pte_dirty(pmd_pte(pmd)) #define mk_pmd(page, prot) pte_pmd(mk_pte(page, prot)) +#define pfn_pmd(pfn, prot) (__pmd(((pfn) << PAGE_SHIFT) | pgprot_val(prot))) +#ifdef CONFIG_TRANSPARENT_HUGEPAGE #define pmd_trans_huge(pmd) (pmd_val(pmd) & _PAGE_HW_SZ) -#define pfn_pmd(pfn, prot) (__pmd(((pfn) << PAGE_SHIFT) | pgprot_val(prot))) - static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot) { /* @@ -73,5 +73,6 @@ extern void flush_pmd_tlb_range(struct vm_area_struct *vma, unsigned long start, /* We don't have hardware dirty/accessed bits, generic_pmdp_establish is fine.*/ #define pmdp_establish generic_pmdp_establish +#endif #endif diff --git a/arch/arc/include/asm/pgtable.h b/arch/arc/include/asm/pgtable.h index 9019ed9..20395f1 100644 --- a/arch/arc/include/asm/pgtable.h +++ b/arch/arc/include/asm/pgtable.h @@ -385,7 +385,7 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long address, * remap a physical page `pfn' of size `size' with page protection `prot' * into virtual address `from' */ -#ifdef CONFIG_TRANSPARENT_HUGEPAGE +#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE #include #endif > > Other than that the tests pass for !THP and THP too. So once fixed, you could Glad that it works on arc platform as well. > enable that for ARC as well> Thx for doing this. > > -Vineet >