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=-11.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,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 00E8EC388F2 for ; Mon, 2 Nov 2020 09:20:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9B24F222E8 for ; Mon, 2 Nov 2020 09:20:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Zu2waH4r" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728275AbgKBJT6 (ORCPT ); Mon, 2 Nov 2020 04:19:58 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:51534 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728189AbgKBJT6 (ORCPT ); Mon, 2 Nov 2020 04:19:58 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1604308796; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=7Fw8UzFDCnhqj5U8VjwS50spEGfFEI10XeNVmZ9tLlQ=; b=Zu2waH4rE7HiHb8vMFx50g3SRWcFwIeC9vwC5230amnmz6+2qLjk7kGj6qnwAweLREBQGl 8hehoUD/zJQMD757k02qVeREU07/2dGmQLzOae6n0KP2SFvXGK8W31b/zZ0qWbcIV55Dyo Min5rcJKiPEunm2gWp8iNzhe+JHHBI8= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-374-r38_d9yVPFKybO8Ug1IDcw-1; Mon, 02 Nov 2020 04:19:52 -0500 X-MC-Unique: r38_d9yVPFKybO8Ug1IDcw-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 482D2809DCF; Mon, 2 Nov 2020 09:19:47 +0000 (UTC) Received: from [10.36.113.163] (ovpn-113-163.ams2.redhat.com [10.36.113.163]) by smtp.corp.redhat.com (Postfix) with ESMTP id E85FB1002C16; Mon, 2 Nov 2020 09:19:36 +0000 (UTC) Subject: Re: [PATCH v3 2/4] PM: hibernate: make direct map manipulations more explicit To: Mike Rapoport , Andrew Morton Cc: Albert Ou , Andy Lutomirski , Benjamin Herrenschmidt , Borislav Petkov , Catalin Marinas , Christian Borntraeger , Christoph Lameter , "David S. Miller" , Dave Hansen , David Rientjes , "Edgecombe, Rick P" , "H. Peter Anvin" , Heiko Carstens , Ingo Molnar , Joonsoo Kim , "Kirill A. Shutemov" , Len Brown , Michael Ellerman , Mike Rapoport , Palmer Dabbelt , Paul Mackerras , Paul Walmsley , Pavel Machek , Pekka Enberg , Peter Zijlstra , "Rafael J. Wysocki" , Thomas Gleixner , Vasily Gorbik , Will Deacon , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-pm@vger.kernel.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, sparclinux@vger.kernel.org, x86@kernel.org, "Rafael J . Wysocki" References: <20201101170815.9795-1-rppt@kernel.org> <20201101170815.9795-3-rppt@kernel.org> From: David Hildenbrand Organization: Red Hat GmbH Message-ID: <55cd2a4a-cfa8-d420-66b3-a25fcdd9b876@redhat.com> Date: Mon, 2 Nov 2020 10:19:36 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: <20201101170815.9795-3-rppt@kernel.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org On 01.11.20 18:08, Mike Rapoport wrote: > From: Mike Rapoport > > When DEBUG_PAGEALLOC or ARCH_HAS_SET_DIRECT_MAP is enabled a page may be > not present in the direct map and has to be explicitly mapped before it > could be copied. > > Introduce hibernate_map_page() that will explicitly use > set_direct_map_{default,invalid}_noflush() for ARCH_HAS_SET_DIRECT_MAP case > and debug_pagealloc_map_pages() for DEBUG_PAGEALLOC case. > > The remapping of the pages in safe_copy_page() presumes that it only > changes protection bits in an existing PTE and so it is safe to ignore > return value of set_direct_map_{default,invalid}_noflush(). > > Still, add a WARN_ON() so that future changes in set_memory APIs will not > silently break hibernation. > > Signed-off-by: Mike Rapoport > Acked-by: Rafael J. Wysocki > --- > include/linux/mm.h | 12 ------------ > kernel/power/snapshot.c | 30 ++++++++++++++++++++++++++++-- > 2 files changed, 28 insertions(+), 14 deletions(-) > > diff --git a/include/linux/mm.h b/include/linux/mm.h > index 1fc0609056dc..14e397f3752c 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -2927,16 +2927,6 @@ static inline bool debug_pagealloc_enabled_static(void) > #if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_ARCH_HAS_SET_DIRECT_MAP) > extern void __kernel_map_pages(struct page *page, int numpages, int enable); > > -/* > - * When called in DEBUG_PAGEALLOC context, the call should most likely be > - * guarded by debug_pagealloc_enabled() or debug_pagealloc_enabled_static() > - */ > -static inline void > -kernel_map_pages(struct page *page, int numpages, int enable) > -{ > - __kernel_map_pages(page, numpages, enable); > -} > - > static inline void debug_pagealloc_map_pages(struct page *page, > int numpages, int enable) > { > @@ -2948,8 +2938,6 @@ static inline void debug_pagealloc_map_pages(struct page *page, > extern bool kernel_page_present(struct page *page); > #endif /* CONFIG_HIBERNATION */ > #else /* CONFIG_DEBUG_PAGEALLOC || CONFIG_ARCH_HAS_SET_DIRECT_MAP */ > -static inline void > -kernel_map_pages(struct page *page, int numpages, int enable) {} > static inline void debug_pagealloc_map_pages(struct page *page, > int numpages, int enable) {} > #ifdef CONFIG_HIBERNATION > diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c > index 46b1804c1ddf..054c8cce4236 100644 > --- a/kernel/power/snapshot.c > +++ b/kernel/power/snapshot.c > @@ -76,6 +76,32 @@ static inline void hibernate_restore_protect_page(void *page_address) {} > static inline void hibernate_restore_unprotect_page(void *page_address) {} > #endif /* CONFIG_STRICT_KERNEL_RWX && CONFIG_ARCH_HAS_SET_MEMORY */ > > +static inline void hibernate_map_page(struct page *page, int enable) > +{ > + if (IS_ENABLED(CONFIG_ARCH_HAS_SET_DIRECT_MAP)) { > + unsigned long addr = (unsigned long)page_address(page); > + int ret; > + > + /* > + * This should not fail because remapping a page here means > + * that we only update protection bits in an existing PTE. > + * It is still worth to have WARN_ON() here if something > + * changes and this will no longer be the case. > + */ > + if (enable) > + ret = set_direct_map_default_noflush(page); > + else > + ret = set_direct_map_invalid_noflush(page); > + > + if (WARN_ON(ret)) > + return; People seem to prefer pr_warn() now that production kernels have panic on warn enabled. It's weird. > + > + flush_tlb_kernel_range(addr, addr + PAGE_SIZE); > + } else { > + debug_pagealloc_map_pages(page, 1, enable); Reviewed-by: David Hildenbrand -- Thanks, David / dhildenb