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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 3AE32C433EF for ; Tue, 26 Apr 2022 14:27:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=tV63SNaOG9rrlhL1bvGXKDQTzEc1pv74bgQZ1eLroHo=; b=jE/gGpz77G/7v+ JMDyxp+AVJ3cYuZT2mA+taZZx9fwcONCBlVVOkXeMzyTeJn5S2oV1ch1a4JmLJJU2ZRkf9Nrz5C7k yd4DPdeKEBaAlLGj/+5La3mmVHbXSG6tlcCOHGyXucrJ8PcxqQExl6EgSsXB0aHhQnMN9hPQ7cdOW dqlUPsOT9IxHpnjBime6RbGRKmVwMvd2Xhs/XP+xgL0eZ2KYglsgdeltQgUxvkjHVInfSNOhtoZPz QsCmxKXqapLR0C/nCKlPKXQoYYcMqp9rlbXuIcOJw+Zm5uM+SkuVeauZEkWeDo8shSAL1OFOgT8KF x5TG8Liq9/CHX+WCZ8ig==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1njM9L-00EzhF-Ml; Tue, 26 Apr 2022 14:26:43 +0000 Received: from dfw.source.kernel.org ([2604:1380:4641:c500::1]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1njM9F-00EzeY-JO; Tue, 26 Apr 2022 14:26:39 +0000 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 2405661842; Tue, 26 Apr 2022 14:26:37 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 916BFC385AA; Tue, 26 Apr 2022 14:26:31 +0000 (UTC) Date: Tue, 26 Apr 2022 15:26:28 +0100 From: Catalin Marinas To: Zhen Lei Cc: Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, "H . Peter Anvin" , linux-kernel@vger.kernel.org, Dave Young , Baoquan He , Vivek Goyal , Eric Biederman , kexec@lists.infradead.org, Will Deacon , linux-arm-kernel@lists.infradead.org, Rob Herring , Frank Rowand , devicetree@vger.kernel.org, Jonathan Corbet , linux-doc@vger.kernel.org, Randy Dunlap , Feng Zhou , Kefeng Wang , Chen Zhou , John Donnelly , Dave Kleikamp Subject: Re: [PATCH v22 4/9] arm64: kdump: Don't force page-level mappings for memory above 4G Message-ID: References: <20220414115720.1887-1-thunder.leizhen@huawei.com> <20220414115720.1887-5-thunder.leizhen@huawei.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20220414115720.1887-5-thunder.leizhen@huawei.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220426_072637_692240_090FA60F X-CRM114-Status: GOOD ( 17.72 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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 On Thu, Apr 14, 2022 at 07:57:15PM +0800, Zhen Lei wrote: > @@ -540,13 +540,31 @@ static void __init map_mem(pgd_t *pgdp) > for_each_mem_range(i, &start, &end) { > if (start >= end) > break; > + > +#ifdef CONFIG_KEXEC_CORE > + if (eflags && (end >= SZ_4G)) { > + /* > + * The memory block cross the 4G boundary. > + * Forcibly use page-level mappings for memory under 4G. > + */ > + if (start < SZ_4G) { > + __map_memblock(pgdp, start, SZ_4G - 1, > + pgprot_tagged(PAGE_KERNEL), flags | eflags); > + start = SZ_4G; > + } > + > + /* Page-level mappings is not mandatory for memory above 4G */ > + eflags = 0; > + } > +#endif That's a bit tricky if a SoC has all RAM above 4G. IIRC AMD Seattle had this layout. See max_zone_phys() for how we deal with this, basically extending ZONE_DMA to the whole range if RAM starts above 4GB. In that case, crashkernel reservation would fall in the range above 4GB. BTW, we changed the max_zone_phys() logic with commit 791ab8b2e3db ("arm64: Ignore any DMA offsets in the max_zone_phys() calculation"). -- Catalin _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel