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=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 213B5C43140 for ; Fri, 6 Sep 2019 15:18:44 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id E5D9120650 for ; Fri, 6 Sep 2019 15:18:43 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E5D9120650 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 95D0F6B0003; Fri, 6 Sep 2019 11:18:43 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 90D376B0006; Fri, 6 Sep 2019 11:18:43 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 8229D6B000D; Fri, 6 Sep 2019 11:18:43 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0108.hostedemail.com [216.40.44.108]) by kanga.kvack.org (Postfix) with ESMTP id 5E00C6B0003 for ; Fri, 6 Sep 2019 11:18:43 -0400 (EDT) Received: from smtpin29.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with SMTP id 111B1824CA3E for ; Fri, 6 Sep 2019 15:18:43 +0000 (UTC) X-FDA: 75904852926.29.son75_11ddc858ddb16 X-HE-Tag: son75_11ddc858ddb16 X-Filterd-Recvd-Size: 4110 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf25.hostedemail.com (Postfix) with ESMTP for ; Fri, 6 Sep 2019 15:18:42 +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 A95341576; Fri, 6 Sep 2019 08:18:41 -0700 (PDT) Received: from [10.1.196.105] (unknown [10.1.196.105]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 8B82E3F59C; Fri, 6 Sep 2019 08:18:38 -0700 (PDT) From: James Morse Subject: Re: [PATCH v3 07/17] arm64, hibernate: move page handling function to new trans_pgd.c To: Pavel Tatashin References: <20190821183204.23576-1-pasha.tatashin@soleen.com> <20190821183204.23576-8-pasha.tatashin@soleen.com> Cc: jmorris@namei.org, sashal@kernel.org, ebiederm@xmission.com, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, corbet@lwn.net, catalin.marinas@arm.com, will@kernel.org, linux-arm-kernel@lists.infradead.org, marc.zyngier@arm.com, vladimir.murzin@arm.com, matthias.bgg@gmail.com, bhsharma@redhat.com, linux-mm@kvack.org, mark.rutland@arm.com Message-ID: Date: Fri, 6 Sep 2019 16:18:37 +0100 User-Agent: Mozilla/5.0 (X11; Linux aarch64; rv:60.0) Gecko/20100101 Thunderbird/60.7.2 MIME-Version: 1.0 In-Reply-To: <20190821183204.23576-8-pasha.tatashin@soleen.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-GB Content-Transfer-Encoding: 7bit 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: Hi Pavel, On 21/08/2019 19:31, Pavel Tatashin wrote: > Now, that we abstracted the required functions move them to a new home. > Later, we will generalize these function in order to be useful outside > of hibernation. > diff --git a/arch/arm64/mm/trans_pgd.c b/arch/arm64/mm/trans_pgd.c > new file mode 100644 > index 000000000000..00b62d8640c2 > --- /dev/null > +++ b/arch/arm64/mm/trans_pgd.c > @@ -0,0 +1,211 @@ > +// SPDX-License-Identifier: GPL-2.0 > + > +/* > + * Copyright (c) 2019, Microsoft Corporation. > + * Pavel Tatashin Hmmm, while line-count isn't a useful metric: this file contains 41% of the code that was in hibernate.c, but has stripped the substantial copyright-pedigree that the hibernate code had built up over the years. (counting lines identified by 'cloc' as code, not comments or blank) If you are copying or moving a non trivial quantity of code, you need to preserve the copyright. Something like 'Derived from the arm64 hibernate support which has:'.... > + */ > + > +/* > + * Transitional tables are used during system transferring from one world to > + * another: such as during hibernate restore, and kexec reboots. During these > + * phases one cannot rely on page table not being overwritten. I think you need to mention that hibernate and kexec are rewriting memory, and may overwrite the live page tables, therefore ... > + * > + */ > + > +#include > +#include > +#include > +#include #include #include #include > +static void _copy_pte(pte_t *dst_ptep, pte_t *src_ptep, unsigned long addr) > +{ > + pte_t pte = READ_ONCE(*src_ptep); > + > + if (pte_valid(pte)) { > + /* > + * Resume will overwrite areas that may be marked > + * read only (code, rodata). Clear the RDONLY bit from > + * the temporary mappings we use during restore. > + */ > + set_pte(dst_ptep, pte_mkwrite(pte)); > + } else if (debug_pagealloc_enabled() && !pte_none(pte)) { > + /* > + * debug_pagealloc will removed the PTE_VALID bit if > + * the page isn't in use by the resume kernel. It may have > + * been in use by the original kernel, in which case we need > + * to put it back in our copy to do the restore. > + * > + * Before marking this entry valid, check the pfn should > + * be mapped. > + */ > + BUG_ON(!pfn_valid(pte_pfn(pte))); Thanks, James