On 22/08/2016:10:29:20 AM, AKASHI Takahiro wrote: > On Fri, Aug 19, 2016 at 04:52:17PM +0530, Pratyush Anand wrote: > > On 19/08/2016:10:26:52 AM, AKASHI Takahiro wrote: > > > >From 740563e4a437f0d6ecf6e421c91433f9b8f19041 Mon Sep 17 00:00:00 2001 > > > From: AKASHI Takahiro <[email protected]> > > > Date: Fri, 19 Aug 2016 09:57:52 +0900 > > > Subject: [PATCH] arm64: mark reserved memblock regions explicitly > > > > > > --- > > > arch/arm64/kernel/setup.c | 9 +++++++-- > > > 1 file changed, 7 insertions(+), 2 deletions(-) > > > > > > diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c > > > index 38eda13..38589b5 100644 > > > --- a/arch/arm64/kernel/setup.c > > > +++ b/arch/arm64/kernel/setup.c > > > @@ -205,10 +205,15 @@ static void __init request_standard_resources(void) > > > > > > for_each_memblock(memory, region) { > > > res = alloc_bootmem_low(sizeof(*res)); > > > - res->name = "System RAM"; > > > + if (memblock_is_nomap(region)) { > > > + res->name = "reserved"; > > > + res->flags = IORESOURCE_MEM | IORESOURCE_BUSY; > > > + } else { > > > + res->name = "System RAM"; > > > + res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY; > > > + } > > > res->start = > > > __pfn_to_phys(memblock_region_memory_base_pfn(region)); > > > res->end = > > > __pfn_to_phys(memblock_region_memory_end_pfn(region)) - 1; > > > - res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY; > > > > > > request_resource(&iomem_resource, res); > > > > > > It will help kexec-tools to prevent copying of any unnecessary data. I > > think, then you also need to change phys_offset calculation in kexec-tools. > > That > > should be start of either of first "reserved" or "System RAM" block. > > Good point, but I'm not sure this is always true. > Is there any system whose ACPI memory is *not* part of DRAM > (so not part of linear mapping)? >
Looking into kernel/resource.c:reserve_setup(), it seems that there could be some none-DRAM area as well, which could be marked as "reserved". So, I think if we mark nomap region as "reserved" then applications like kexec-tools may not always identify start of DRAM correctly. Probably, we should give an unique name to reserved system ram area. ~Pratyush _______________________________________________ kexec mailing list [email protected] http://lists.infradead.org/mailman/listinfo/kexec
