From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from us-smtp-2.mimecast.com ([207.211.31.81] helo=us-smtp-delivery-1.mimecast.com) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jY3ug-0004PD-1S for kexec@lists.infradead.org; Mon, 11 May 2020 08:35:51 +0000 Subject: Re: [PATCH 2/3] mm/memory_hotplug: Allow arch override of non boot memory resource names References: <20200326180730.4754-1-james.morse@arm.com> <20200326180730.4754-3-james.morse@arm.com> <20200508174536.77c7aa3d5d0220cedd07f2e9@linux-foundation.org> From: David Hildenbrand Message-ID: Date: Mon, 11 May 2020 10:35:01 +0200 MIME-Version: 1.0 In-Reply-To: <20200508174536.77c7aa3d5d0220cedd07f2e9@linux-foundation.org> Content-Language: en-US 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: Andrew Morton , James Morse Cc: Anshuman Khandual , Catalin Marinas , Bhupesh Sharma , kexec@lists.infradead.org, linux-mm@kvack.org, Eric Biederman , Will Deacon , linux-arm-kernel@lists.infradead.org On 09.05.20 02:45, Andrew Morton wrote: > 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]. @Andrew, as discussed in this thread already [1], I suggest to drop this series from -mm tree for now. [1] https://lkml.kernel.org/r/2e3419b2-d00c-51c3-9b45-9de114608cdf@arm.com -- Thanks, David / dhildenb _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec