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=-13.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,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 9A32CC4727C for ; Tue, 29 Sep 2020 13:58:04 +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 A9F71206B7 for ; Tue, 29 Sep 2020 13:58:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="IoeINdRK" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A9F71206B7 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+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=IbeD4OnRWlsGY0meErwCXp5onWtc2K7NAajY3868fZE=; b=IoeINdRKCy8G+bZ3Vtlt3dLT2+ 1nd8O5zdJYlRlc0RxXXScgXXxq7IdQYaBp2Cf1yo+NjyL8R5kZUtHWggZPS0LQtwg6YVL+e127TuI ODGPq1R5gImgCpoTQHtmPHd4Hw+OVBiaLw0vrD6TUvxMrkZvZV2Sqf873Rba0Zi16l4/cRDS73LLF DENg2jb1CsbOY2r/NTYdOCyyh6sRiZTthM20NwRQcK8cuDNdLRNf+5ct+38YRLMNtn9NBcjAVaHMV /C8ic3DDt1SYqkMV25KVCsaXcS5W1rHK2fk/tjJAO3C68lM0f38/vnTbKKePNDP7szqo7mgSpUTsn t7MZ86sQ==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kNG7N-0000mv-CR; Tue, 29 Sep 2020 13:56:33 +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 1kNG6b-0000VO-L7 for linux-arm-kernel@lists.infradead.org; Tue, 29 Sep 2020 13:55:46 +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 C13BE31B; Tue, 29 Sep 2020 06:55:44 -0700 (PDT) Received: from p8cg001049571a15.blr.arm.com (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 48E243F6CF; Tue, 29 Sep 2020 06:55:40 -0700 (PDT) From: Anshuman Khandual To: linux-arm-kernel@lists.infradead.org Subject: [PATCH V4 3/3] arm64/mm/hotplug: Ensure early memory sections are all online Date: Tue, 29 Sep 2020 19:24:47 +0530 Message-Id: <1601387687-6077-4-git-send-email-anshuman.khandual@arm.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1601387687-6077-1-git-send-email-anshuman.khandual@arm.com> References: <1601387687-6077-1-git-send-email-anshuman.khandual@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200929_095545_925808_350E29AF X-CRM114-Status: GOOD ( 20.71 ) 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 , gshan@redhat.com, Anshuman Khandual , catalin.marinas@arm.com, Steve Capper , linux-kernel@vger.kernel.org, Mark Brown , Marc Zyngier , will@kernel.org 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 This adds a validation function that scans the entire boot memory and makes sure that all early memory sections are online. This check is essential for the memory notifier to work properly, as it cannot prevent any boot memory from offlining, if all sections are not online to begin with. The notifier registration is skipped, if this validation does not go through. Although the boot section scanning is selectively enabled with DEBUG_VM. Cc: Catalin Marinas Cc: Will Deacon Cc: Mark Rutland Cc: Marc Zyngier Cc: Steve Capper Cc: Mark Brown Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Anshuman Khandual --- arch/arm64/mm/mmu.c | 59 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 59 insertions(+) diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index 90a30f5ebfc0..b67a657ea1ad 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -1522,6 +1522,62 @@ static struct notifier_block prevent_bootmem_remove_nb = { .notifier_call = prevent_bootmem_remove_notifier, }; +/* + * This ensures that boot memory sections on the plaltform are online + * during early boot. They could not be prevented from being offlined + * if for some reason they are not brought online to begin with. This + * help validate the basic assumption on which the above memory event + * notifier works to prevent boot memory offlining and it's possible + * removal. + */ +static bool validate_bootmem_online(void) +{ + struct memblock_region *mblk; + struct mem_section *ms; + unsigned long pfn, end_pfn, start, end; + bool all_online = true; + + /* + * Scanning across all memblock might be expensive + * on some big memory systems. Hence enable this + * validation only with DEBUG_VM. + */ + if (!IS_ENABLED(CONFIG_DEBUG_VM)) + return all_online; + + for_each_memblock(memory, mblk) { + pfn = PHYS_PFN(mblk->base); + end_pfn = PHYS_PFN(mblk->base + mblk->size); + + for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) { + ms = __pfn_to_section(pfn); + + /* + * All memory ranges in the system at this point + * should have been marked early sections. + */ + WARN_ON(!early_section(ms)); + + /* + * Memory notifier mechanism here to prevent boot + * memory offlining depends on the fact that each + * early section memory on the system is intially + * online. Otherwise a given memory section which + * is already offline will be overlooked and can + * be removed completely. Call out such sections. + */ + if (!online_section(ms)) { + start = PFN_PHYS(pfn); + end = start + (1UL << PA_SECTION_SHIFT); + pr_err("Memory range [%lx %lx] is offline\n", start, end); + pr_err("Memory range [%lx %lx] can be removed\n", start, end); + all_online = false; + } + } + } + return all_online; +} + static int __init prevent_bootmem_remove_init(void) { int ret = 0; @@ -1529,6 +1585,9 @@ static int __init prevent_bootmem_remove_init(void) if (!IS_ENABLED(CONFIG_MEMORY_HOTREMOVE)) return ret; + if (!validate_bootmem_online()) + return -EINVAL; + ret = register_memory_notifier(&prevent_bootmem_remove_nb); if (ret) pr_err("%s: Notifier registration failed %d\n", __func__, ret); -- 2.20.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel