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=-0.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no 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 C1D3EC38A2A for ; Sat, 9 May 2020 00:45:39 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 845B721655 for ; Sat, 9 May 2020 00:45:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="q24fb/5O" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 845B721655 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 0E09F900026; Fri, 8 May 2020 20:45:39 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 091AC90001C; Fri, 8 May 2020 20:45:39 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id EE918900026; Fri, 8 May 2020 20:45:38 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0216.hostedemail.com [216.40.44.216]) by kanga.kvack.org (Postfix) with ESMTP id D33CE90001C for ; Fri, 8 May 2020 20:45:38 -0400 (EDT) Received: from smtpin27.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 8D124181AEF1A for ; Sat, 9 May 2020 00:45:38 +0000 (UTC) X-FDA: 76795337556.27.limit40_141d8879f7010 X-HE-Tag: limit40_141d8879f7010 X-Filterd-Recvd-Size: 3952 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf08.hostedemail.com (Postfix) with ESMTP for ; Sat, 9 May 2020 00:45:37 +0000 (UTC) Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id D491421582; Sat, 9 May 2020 00:45:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588985137; bh=fkIkzzGIPxBuqh2taVX4dHP53jKpIlLL4G7UFSelXHE=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=q24fb/5O8tgeilvfX4b7SugL2BvyR6UX/WCLg2p1yDYz0kKinDa+wXN6wOMDyItJv if7HTpifPbslDIdZgc1OGCleR1d708yuSYyzHq6dWc/Ig6VcyItzJ1yC21TSSWy8i1 CxfafuJ9yOBqVZuPJoMB/qSQ8imHOb19WHD82aUU= Date: Fri, 8 May 2020 17:45:36 -0700 From: Andrew Morton To: James Morse Cc: kexec@lists.infradead.org, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, Eric Biederman , Catalin Marinas , Will Deacon , Anshuman Khandual , Bhupesh Sharma Subject: Re: [PATCH 2/3] mm/memory_hotplug: Allow arch override of non boot memory resource names Message-Id: <20200508174536.77c7aa3d5d0220cedd07f2e9@linux-foundation.org> In-Reply-To: <20200326180730.4754-3-james.morse@arm.com> References: <20200326180730.4754-1-james.morse@arm.com> <20200326180730.4754-3-james.morse@arm.com> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.31; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu, 26 Mar 2020 18:07:29 +0000 James Morse wrote: > Memory added to the system by hotplug has a 'System RAM' resource created > for it. This is exposed to user-space via /proc/iomem. > > This poses problems for kexec on arm64. If kexec decides to place the > kernel in one of these newly onlined regions, the new kernel will find > itself booting from a region not described as memory in the firmware > tables. > > Arm64 doesn't have a structure like the e820 memory map that can be > re-written when memory is brought online. Instead arm64 uses the UEFI > memory map, or the memory node from the DT, sometimes both. We never > rewrite these. > > Allow an architecture to specify a different name for these hotplug > regions. > > ... > > --- a/mm/memory_hotplug.c > +++ b/mm/memory_hotplug.c > @@ -42,6 +42,10 @@ > #include "internal.h" > #include "shuffle.h" > > +#ifndef MEMORY_HOTPLUG_RES_NAME > +#define MEMORY_HOTPLUG_RES_NAME "System RAM" > +#endif > + > /* > * online_page_callback contains pointer to current page onlining function. > * Initially it is generic_online_page(). If it is required it could be > @@ -103,7 +107,7 @@ static struct resource *register_memory_resource(u64 start, u64 size) > { > struct resource *res; > unsigned long flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY; > - char *resource_name = "System RAM"; > + char *resource_name = MEMORY_HOTPLUG_RES_NAME; > > if (start + size > max_mem_size) > return ERR_PTR(-E2BIG); I suppose we should do this as well: --- a/mm/memory_hotplug.c~mm-memory_hotplug-allow-arch-override-of-non-boot-memory-resource-names-fix +++ a/mm/memory_hotplug.c @@ -129,7 +129,8 @@ static struct resource *register_memory_ resource_name, flags); if (!res) { - pr_debug("Unable to reserve System RAM region: %016llx->%016llx\n", + pr_debug("Unable to reserve " MEMORY_HOTPLUG_RES_NAME + " region: %016llx->%016llx\n", start, start + size); return ERR_PTR(-EEXIST); } It assumes that MEMORY_HOTPLUG_RES_NAME will be a literal string, which is the case in [3/3].