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=-17.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT 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 0E51BC433DB for ; Tue, 2 Feb 2021 04:13:05 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (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 9F74664E95 for ; Tue, 2 Feb 2021 04:13:04 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9F74664E95 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+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=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:MIME-Version:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:References:In-Reply-To:Message-Id:Date:Subject:To: From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=BFpFpmzT1aqbAdOKUbLvY1trRWSM7YUH5xkLmnDIHTY=; b=FHvEs1n6DbD1sO3F0MOEYXaiN7 hWqvCsbIC/42WYkYUSZGpoLNXNJuTc0tbhi9D5wmtKZ3ZmCzgve3EFSUUlbtAWOMi+yV4RMsGQXZC iPbXu2vRmXh7vDzx2wE+gR8xkAPLDyckR/B+6ibEAtUhBHoKe3Tb4yTRakHmy5lmpddLz1aTANgec 5b7Vzt2mw7r7H0ydsqdqUFzSIXGPLgFS6Rq3E5dxuc4fs0WS/PhgzZKnFENCqs6tM2dnol20WVDor splS4IiIKuSmvxrP54j8Nhvn+3E8k81efulPhvK2x2DiFhDyGhkqhWRj+9xybkfszobOkTgmDtSM3 R2hd2QbQ==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1l6n2f-00022A-F6; Tue, 02 Feb 2021 04:11:53 +0000 Received: from foss.arm.com ([217.140.110.172]) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1l6n2b-00021T-VE for linux-arm-kernel@lists.infradead.org; Tue, 02 Feb 2021 04:11:52 +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 01C3F1509; Mon, 1 Feb 2021 20:11:43 -0800 (PST) Received: from p8cg001049571a15.blr.arm.com (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 117133F66E; Mon, 1 Feb 2021 20:11:37 -0800 (PST) From: Anshuman Khandual To: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH V2 1/2] arm64/mm: Fix pfn_valid() for ZONE_DEVICE based memory Date: Tue, 2 Feb 2021 09:41:53 +0530 Message-Id: <1612239114-28428-2-git-send-email-anshuman.khandual@arm.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1612239114-28428-1-git-send-email-anshuman.khandual@arm.com> References: <1612239114-28428-1-git-send-email-anshuman.khandual@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210201_231151_213585_879F717C X-CRM114-Status: GOOD ( 16.96 ) 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 , Anshuman Khandual , Catalin Marinas , David Hildenbrand , Robin Murphy , Mike Rapoport , =?UTF-8?q?J=C3=A9r=C3=B4me=20Glisse?= , James Morse , Dan Williams , Will Deacon , Ard Biesheuvel MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org pfn_valid() validates a pfn but basically it checks for a valid struct page backing for that pfn. It should always return positive for memory ranges backed with struct page mapping. But currently pfn_valid() fails for all ZONE_DEVICE based memory types even though they have struct page mapping. pfn_valid() asserts that there is a memblock entry for a given pfn without MEMBLOCK_NOMAP flag being set. The problem with ZONE_DEVICE based memory is that they do not have memblock entries. Hence memblock_is_map_memory() will invariably fail via memblock_search() for a ZONE_DEVICE based address. This eventually fails pfn_valid() which is wrong. memblock_is_map_memory() needs to be skipped for such memory ranges. As ZONE_DEVICE memory gets hotplugged into the system via memremap_pages() called from a driver, their respective memory sections will not have SECTION_IS_EARLY set. Normal hotplug memory will never have MEMBLOCK_NOMAP set in their memblock regions. Because the flag MEMBLOCK_NOMAP was specifically designed and set for firmware reserved memory regions. memblock_is_map_memory() can just be skipped as its always going to be positive and that will be an optimization for the normal hotplug memory. Like ZONE_DEVICE based memory, all normal hotplugged memory too will not have SECTION_IS_EARLY set for their sections Skipping memblock_is_map_memory() for all non early memory sections would fix pfn_valid() problem for ZONE_DEVICE based memory and also improve its performance for normal hotplug memory as well. Cc: Catalin Marinas Cc: Will Deacon Cc: Ard Biesheuvel Cc: Robin Murphy Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Acked-by: David Hildenbrand Fixes: 73b20c84d42d ("arm64: mm: implement pte_devmap support") Signed-off-by: Anshuman Khandual --- arch/arm64/mm/init.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c index 709d98fea90c..1141075e4d53 100644 --- a/arch/arm64/mm/init.c +++ b/arch/arm64/mm/init.c @@ -230,6 +230,18 @@ int pfn_valid(unsigned long pfn) if (!valid_section(__pfn_to_section(pfn))) return 0; + + /* + * ZONE_DEVICE memory does not have the memblock entries. + * memblock_is_map_memory() check for ZONE_DEVICE based + * addresses will always fail. Even the normal hotplugged + * memory will never have MEMBLOCK_NOMAP flag set in their + * memblock entries. Skip memblock search for all non early + * memory sections covering all of hotplug memory including + * both normal and ZONE_DEVICE based. + */ + if (!early_section(__pfn_to_section(pfn))) + return pfn_section_valid(__pfn_to_section(pfn), pfn); #endif return memblock_is_map_memory(addr); } -- 2.20.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel