From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: From: ebiederm@xmission.com (Eric W. Biederman) References: <20200326180730.4754-1-james.morse@arm.com> <20200326180730.4754-3-james.morse@arm.com> Date: Wed, 15 Apr 2020 15:36:12 -0500 In-Reply-To: <20200326180730.4754-3-james.morse@arm.com> (James Morse's message of "Thu, 26 Mar 2020 18:07:29 +0000") Message-ID: <873694h4g3.fsf@x220.int.ebiederm.org> MIME-Version: 1.0 Subject: Re: [PATCH 2/3] mm/memory_hotplug: Allow arch override of non boot memory resource names List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: James Morse Cc: Anshuman Khandual , Catalin Marinas , Bhupesh Sharma , kexec@lists.infradead.org, linux-mm@kvack.org, Andrew Morton , Will Deacon , linux-arm-kernel@lists.infradead.org James Morse writes: > 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. Gah. No. Please find a way to pass the current memory map to the loaded kexec'd kernel. Starting a kernel with no way for it to know what the current memory map is just plain scary. Eric _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec