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=-2.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,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 8D517C49ED7 for ; Fri, 20 Sep 2019 04:06:22 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 6183020882 for ; Fri, 20 Sep 2019 04:06:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="sUc+VM7r" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6183020882 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date: Message-ID:From:References:To:Subject:Reply-To:Content-ID:Content-Description :Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=mxO8Taek3JZoJVrtBIMp2o2xF7pqPk+VP5/9KkF8rvA=; b=sUc+VM7re2Ra3e V4jsLpQ4x90m8ZsPOMUvKIetIBH+OqREr6Gu1mDA8lQUXv8LbpUFOSSp7TriTMIHFrmn86kZ9p6/6 c5ceHGpZJO6++ML24VepRjJv+O1DcWDMANmN7zpTaOSReHJu8AvlgWDa/C2orvVxnhXm4dnU6hNso 6J3afTcSuaQnLWMno8xSrORy05wqfBR9HDREwB1DFyob5mgh15KFNWbVMZD7+NIt7Te7C5K8uv/UZ WfJcL8mJuiHyeOxfGgyE7CdXoCgV953gEs8XrwRk7MJxEzGW9O8Aaod5dYaVpEHrN8XAebg4Jxr2R GhDlCZSo3VOW6VR3TBNg==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.2 #3 (Red Hat Linux)) id 1iBABU-0000Rq-Sj; Fri, 20 Sep 2019 04:06:16 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92.2 #3 (Red Hat Linux)) id 1iBABR-0000RM-Qf; Fri, 20 Sep 2019 04:06:15 +0000 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 08718337; Thu, 19 Sep 2019 21:06:10 -0700 (PDT) Received: from [10.162.40.137] (p8cg001049571a15.blr.arm.com [10.162.40.137]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 85C4F3F67D; Thu, 19 Sep 2019 21:05:57 -0700 (PDT) Subject: Re: [PATCH V2 2/2] mm/pgtable/debug: Add test validating architecture page table helpers To: Gerald Schaefer , Christophe Leroy References: <1568268173-31302-1-git-send-email-anshuman.khandual@arm.com> <1568268173-31302-3-git-send-email-anshuman.khandual@arm.com> <502c497a-9bf1-7d2e-95f2-cfebcd9cf1d9@arm.com> <95ed9d92-dd43-4c45-2e52-738aed7f2fb5@c-s.fr> <64504101-d9dd-f273-02f9-e9a8b178eecc@c-s.fr> <20190918202243.37e709df@thinkpad> From: Anshuman Khandual Message-ID: <5a6045af-bcfb-12c2-0f4a-3b49a905ec4d@arm.com> Date: Fri, 20 Sep 2019 09:36:12 +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: <20190918202243.37e709df@thinkpad> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190919_210613_954674_D2F043C0 X-CRM114-Status: GOOD ( 21.97 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: 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 , Tetsuo Handa , Heiko Carstens , Michal Hocko , linux-mm@kvack.org, Dave Hansen , Paul Mackerras , sparclinux@vger.kernel.org, Thomas Gleixner , linux-s390@vger.kernel.org, Michael Ellerman , x86@kernel.org, Russell King - ARM Linux , Matthew Wilcox , Steven Price , Jason Gunthorpe , linux-arm-kernel@lists.infradead.org, linux-snps-arc@lists.infradead.org, Kees Cook , Masahiro Yamada , Mark Brown , "Kirill A . Shutemov" , Dan Williams , 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 , Vineet Gupta , Martin Schwidefsky , Andrew Morton , linuxppc-dev@lists.ozlabs.org, "David S. Miller" Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 09/18/2019 11:52 PM, Gerald Schaefer wrote: > On Wed, 18 Sep 2019 18:26:03 +0200 > Christophe Leroy wrote: > > [..] >> My suggestion was not to completely drop the #ifdef but to do like you >> did in pgd_clear_tests() for instance, ie to add the following test on >> top of the function: >> >> if (mm_pud_folded(mm) || is_defined(__ARCH_HAS_5LEVEL_HACK)) >> return; >> > > Ah, very nice, this would also fix the remaining issues for s390. Since > we have dynamic page table folding, neither __PAGETABLE_PXX_FOLDED nor > __ARCH_HAS_XLEVEL_HACK is defined, but mm_pxx_folded() will work. Like Christophe mentioned earlier on the other thread, we will convert all __PGTABLE_PXX_FOLDED checks as mm_pxx_folded() but looks like ARCH_HAS_[4 and 5]LEVEL_HACK macros will still be around. Will respin the series with all agreed upon changes first and probably we can then discuss pending issues from there. > > mm_alloc() returns with a 3-level page table by default on s390, so we > will run into issues in p4d_clear/populate_tests(), and also at the end > with p4d/pud_free() (double free). > > So, adding the mm_pud_folded() check to p4d_clear/populate_tests(), > and also adding mm_p4d/pud_folded() checks at the end before calling> p4d/pud_free(), would make it all work on s390. Atleast p4d_clear/populate_tests() tests will be taken care. > > BTW, regarding p4d/pud_free(), I'm not sure if we should rather check > the folding inside our s390 functions, similar to how we do it for > p4d/pud_free_tlb(), instead of relying on not being called for folded > p4d/pud. So far, I see no problem with this behavior, all callers of > p4d/pud_free() should be fine because of our folding check within > p4d/pud_present/none(). But that doesn't mean that it is correct not > to check for the folding inside p4d/pud_free(). At least, with this > test module we do now have a caller of p4d/pud_free() on potentially > folded entries, so instead of adding pxx_folded() checks to this > test module, we could add them to our p4d/pud_free() functions. > Any thoughts on this? Agreed, it seems better to do the check inside p4d/pud_free() functions. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel