From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f71.google.com (mail-pa0-f71.google.com [209.85.220.71]) by kanga.kvack.org (Postfix) with ESMTP id 500136B0005 for ; Wed, 10 Aug 2016 12:26:49 -0400 (EDT) Received: by mail-pa0-f71.google.com with SMTP id pp5so80639335pac.3 for ; Wed, 10 Aug 2016 09:26:49 -0700 (PDT) Received: from foss.arm.com (foss.arm.com. [217.140.101.70]) by mx.google.com with ESMTP id a68si49121309pfb.39.2016.08.10.09.26.48 for ; Wed, 10 Aug 2016 09:26:48 -0700 (PDT) Message-ID: <57AB55C4.1070200@arm.com> Date: Wed, 10 Aug 2016 17:26:44 +0100 From: James Morse MIME-Version: 1.0 Subject: Re: [PATCH v24 2/9] memblock: add memblock_cap_memory_range() References: <20160809015248.28414-2-takahiro.akashi@linaro.org> <20160809015526.28479-1-takahiro.akashi@linaro.org> In-Reply-To: <20160809015526.28479-1-takahiro.akashi@linaro.org> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: AKASHI Takahiro Cc: catalin.marinas@arm.com, will.deacon@arm.com, geoff@infradead.org, bauerman@linux.vnet.ibm.com, dyoung@redhat.com, mark.rutland@arm.com, kexec@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org Hi Akashi, On 09/08/16 02:55, AKASHI Takahiro wrote: > Crash dump kernel uses only a limited range of memory as System RAM. > On arm64 implementation, a new device tree property, > "linux,usable-memory-range," is used to notify crash dump kernel of > this range.[1] > But simply excluding all the other regions, whatever their memory types > are, doesn't work, especially, on the systems with ACPI. Since some of > such regions will be later mapped as "device memory" by ioremap()/ > acpi_os_ioremap(), it can cause errors like unalignment accesses.[2] > This issue is akin to the one reported in [3]. > > So this patch follows Chen's approach, and implements a new function, > memblock_cap_memory_range(), which will exclude only the memory regions > that are not marked "NOMAP" from memblock.memory. This (and the next patch) fixes the acpi related unaligned access problem I had. I've tested it on a Juno r1 and Seattle B0. Tested-by: James Morse Thanks, James -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org