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=-5.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 77ABAC4BA24 for ; Thu, 27 Feb 2020 04:07:39 +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 41E4A24687 for ; Thu, 27 Feb 2020 04:07:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="JkIgxv3W" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 41E4A24687 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-riscv-bounces+infradead-linux-riscv=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:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id: Content-Transfer-Encoding:Content-Type: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=ywPsIkgrPJoYIUXoymwbgnam6fT3JNfW7hJSWCMkCyk=; b=JkIgxv3Wr46smT 4VxOyI4EWyZuBxcliAkAbvQotPy8ACzW4tK9x4dt5ppMk2LEiPRakvCD/eWCVzmGRlo57KxrtHItC dVR86MQiyJ3RnZSZc5cVHHbIZ2JhQ9lw24vLNtlvlhjupInLKI7xvn+QmdHElrmVUKzrZ5QYrt0MJ mMm4atC+BwUybr6lJtDjne0fyTv52ThCK2c9uEa1ABtS2/D3Pbja7+GpI17uZbnL4u/GIJJe0+IO4 3PS29x7tUlPZGrBWniOdN5azWgxm0QJ8YnCA2J/wIE5YUtIFr0FP047N0Rz+pjGChODn7P4g2TW18 hAKwkZHBVn2IbRNctUAg==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1j7ASX-0003Pz-KP; Thu, 27 Feb 2020 04:07:37 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1j7ASJ-0003Eh-3L; Thu, 27 Feb 2020 04:07:24 +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 75D6F30E; Wed, 26 Feb 2020 20:07:21 -0800 (PST) Received: from [10.163.1.119] (unknown [10.163.1.119]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id E40F83F73B; Wed, 26 Feb 2020 20:07:11 -0800 (PST) Subject: Re: [PATCH V14] mm/debug: Add tests validating architecture page table helpers To: Andrew Morton References: <1581909460-19148-1-git-send-email-anshuman.khandual@arm.com> <1582726182.7365.123.camel@lca.pw> <1582726340.7365.124.camel@lca.pw> <52db1e9b-83b3-c41f-ef03-0f43e2159a83@arm.com> <20200226200353.ea5c8ec2efacfb1192f3f3f4@linux-foundation.org> From: Anshuman Khandual Message-ID: <6a4518d5-9306-8f84-b676-26a40c594bd9@arm.com> Date: Thu, 27 Feb 2020 09:37:07 +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: <20200226200353.ea5c8ec2efacfb1192f3f3f4@linux-foundation.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200226_200723_226688_821BF9DF X-CRM114-Status: GOOD ( 20.77 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Benjamin Herrenschmidt , Heiko Carstens , linux-mm@kvack.org, Paul Mackerras , "H. Peter Anvin" , linux-riscv@lists.infradead.org, Will Deacon , linux-arch@vger.kernel.org, linux-s390@vger.kernel.org, Michael Ellerman , x86@kernel.org, Mike Rapoport , Christian Borntraeger , Ingo Molnar , Catalin Marinas , James Morse , linux-snps-arc@lists.infradead.org, Vasily Gorbik , Qian Cai , Paul Walmsley , "Kirill A . Shutemov" , Thomas Gleixner , linux-arm-kernel@lists.infradead.org, Christophe Leroy , Vineet Gupta , linux-kernel@vger.kernel.org, Palmer Dabbelt , Borislav Petkov , linuxppc-dev@lists.ozlabs.org Sender: "linux-riscv" Errors-To: linux-riscv-bounces+infradead-linux-riscv=archiver.kernel.org@lists.infradead.org On 02/27/2020 09:33 AM, Andrew Morton wrote: > On Thu, 27 Feb 2020 08:04:05 +0530 Anshuman Khandual wrote: > >>> Must be something wrong with the following in debug_vm_pgtable() >>> >>>     paddr = __pa(&start_kernel); >>> >>> Is there any explaination why start_kernel() is not in linear memory on ARM64 ? >> >> >> Cc: + James Morse >> >> This warning gets exposed with DEBUG_VIRTUAL due to __pa() on a kernel symbol >> i.e 'start_kernel' which might be outside the linear map. This happens due to >> kernel mapping position randomization with KASLR. Adding James here in case he >> might like to add more. >> >> __pa_symbol() should have been used instead, for accessing the physical address >> here. On arm64 __pa() does check for linear address with __is_lm_address() and >> switch accordingly if it is a kernel text symbol. Nevertheless, its much better >> to use __pa_symbol() here rather than __pa(). >> >> Rather than respining the patch once more, will just send a fix replacing this >> helper __pa() with __pa_symbol() for Andrew to pick up as this patch is already >> part of linux-next (next-20200226). But can definitely respin if that will be >> preferred. > > I didn't see this fix? I assume it's this? If so, are we sure it's OK to be > added to -next without testing?? My patch just missed your response here within a minute :) Please consider this. It has been tested on x86 and arm64. https://patchwork.kernel.org/patch/11407715/ > > > > From: Andrew Morton > Subject: mm-debug-add-tests-validating-architecture-page-table-helpers-fix > > A warning gets exposed with DEBUG_VIRTUAL due to __pa() on a kernel symbol > i.e 'start_kernel' which might be outside the linear map. This happens > due to kernel mapping position randomization with KASLR. > > __pa_symbol() should have been used instead, for accessing the physical > address here. On arm64 __pa() does check for linear address with > __is_lm_address() and switch accordingly if it is a kernel text symbol. > Nevertheless, its much better to use __pa_symbol() here rather than > __pa(). > > Reported-by: Qian Cai > Cc: Anshuman Khandual > Cc: James Morse > Cc: Christophe Leroy > Signed-off-by: Andrew Morton > --- > > mm/debug_vm_pgtable.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > --- a/mm/debug_vm_pgtable.c~mm-debug-add-tests-validating-architecture-page-table-helpers-fix > +++ a/mm/debug_vm_pgtable.c > @@ -331,7 +331,7 @@ void __init debug_vm_pgtable(void) > * helps avoid large memory block allocations to be used for mapping > * at higher page table levels. > */ > - paddr = __pa(&start_kernel); > + paddr = __pa_symbol(&start_kernel); > > pte_aligned = (paddr & PAGE_MASK) >> PAGE_SHIFT; > pmd_aligned = (paddr & PMD_MASK) >> PAGE_SHIFT; > _ > >