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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 08C92C3524B for ; Sun, 2 Feb 2020 08:26:26 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id A4099206D3 for ; Sun, 2 Feb 2020 08:26:25 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A4099206D3 Authentication-Results: mail.kernel.org; dmarc=none (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 DDCC26B0626; Sun, 2 Feb 2020 03:26:24 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id D65436B0627; Sun, 2 Feb 2020 03:26:24 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C2D906B0628; Sun, 2 Feb 2020 03:26:24 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0208.hostedemail.com [216.40.44.208]) by kanga.kvack.org (Postfix) with ESMTP id A990E6B0626 for ; Sun, 2 Feb 2020 03:26:24 -0500 (EST) Received: from smtpin25.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 5229F181AEF10 for ; Sun, 2 Feb 2020 08:26:24 +0000 (UTC) X-FDA: 76444505088.25.idea81_8f1856a0af435 X-HE-Tag: idea81_8f1856a0af435 X-Filterd-Recvd-Size: 5453 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf19.hostedemail.com (Postfix) with ESMTP for ; Sun, 2 Feb 2020 08:26:23 +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 3C77E1045; Sun, 2 Feb 2020 00:26:22 -0800 (PST) Received: from [10.163.1.42] (unknown [10.163.1.42]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 53D883F68E; Sun, 2 Feb 2020 00:29:45 -0800 (PST) Subject: Re: [PATCH V12] mm/debug: Add tests validating architecture page table helpers To: Christophe Leroy , linux-mm@kvack.org Cc: Andrew Morton , Vlastimil Babka , Greg Kroah-Hartman , Thomas Gleixner , Mike Rapoport , Jason Gunthorpe , Dan Williams , Peter Zijlstra , Michal Hocko , Mark Rutland , Mark Brown , Steven Price , Ard Biesheuvel , Masahiro Yamada , Kees Cook , Tetsuo Handa , Matthew Wilcox , Sri Krishna chowdary , Dave Hansen , Russell King - ARM Linux , Michael Ellerman , Paul Mackerras , Martin Schwidefsky , Heiko Carstens , "David S. Miller" , Vineet Gupta , James Hogan , Paul Burton , Ralf Baechle , "Kirill A . Shutemov" , Gerald Schaefer , Ingo Molnar , linux-snps-arc@lists.infradead.org, linux-mips@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-ia64@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org References: <1580174873-18117-1-git-send-email-anshuman.khandual@arm.com> <68ed6488-aa25-ab41-8da6-f0ddeb15d52b@c-s.fr> <49754f74-53a7-0e4a-bb16-53617f8c902c@arm.com> From: Anshuman Khandual Message-ID: Date: Sun, 2 Feb 2020 13:56:04 +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: <49754f74-53a7-0e4a-bb16-53617f8c902c@arm.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable 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 01/30/2020 06:34 PM, Anshuman Khandual wrote: > On 01/28/2020 10:35 PM, Christophe Leroy wrote: >> >> Le 28/01/2020 =C3=A0 02:27, Anshuman Khandual a =C3=A9crit=C2=A0: >>> This adds tests which will validate architecture page table helpers a= nd >>> other accessors in their compliance with expected generic MM semantic= s. >>> This will help various architectures in validating changes to existin= g >>> 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 vari= ous >>> 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 call= ed >>> right after page_alloc_init_late(). >>> >>> This gets build and run when CONFIG_DEBUG_VM_PGTABLE is selected alon= g with >>> CONFIG_VM_DEBUG. Architectures willing to subscribe this test also ne= ed to >>> select CONFIG_ARCH_HAS_DEBUG_VM_PGTABLE which for now is limited to x= 86 and >>> arm64. Going forward, other architectures too can enable this after f= ixing >>> build or runtime problems (if any) with their page table helpers. >>> >>> Folks interested in making sure that a given platform's page table he= lpers >>> conform to expected generic MM semantics should enable the above conf= ig >>> which will just trigger this test during boot. Any non conformity her= e will >>> be reported as an warning which would need to be fixed. This test wil= l help >>> catch any changes to the agreed upon semantics expected from generic = MM and >>> enable platforms to accommodate it thereafter. >>> >> [...] >> >>> Tested-by: Christophe Leroy =C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0=C2=A0 #PPC32 >> Also tested on PPC64 (under QEMU): book3s/64 64k pages, book3s/64 4k p= ages and book3e/64 > Hmm but earlier Michael Ellerman had reported some problems while > running these tests on PPC64, a soft lock up in hash__pte_update() > and a kernel BUG (radix MMU). Are those problems gone away now ? >=20 > Details in this thread - https://patchwork.kernel.org/patch/11214603/ >=20 It is always better to have more platforms enabled than not. But lets kee= p this test disabled on PPC64 for now, if there is any inconsistency betwee= n results while running this under QEMU and on actual systems.