On Wed, May 11, 2016 at 04:29:23PM +0800, Dave Young wrote: > Hi, Russell > > On 04/28/16 at 10:26am, Russell King - ARM Linux wrote: > > These changes are required for TI Keystone2 kexec to be functional. TI > > Keystone2 has the run-time view of physical memory above 4GiB, but with > > a boot time alias below 4GiB which can only be used during the early > > boot. > > > > This means we need to translate run-time physical addresses (which the > > kernel uses) to boot-time physical addresses, which, having discussed > > with Eric, is what the kexec tools and kexec kernel API requires. > > > > We publish a special set of boot time resources in /proc/iomem, which > > the (modified) kexec tools look for in preference to the normal resources. > > Hence, if these are found, the kexec tools make use of these resources, > > and thus kexec tools use the boot-time view of physical memory. > > I think getting memory ranges from device tree will be better than > adding more stuff to /proc/iomem. Geoff's arm64 kexec patches is using dtb > you can refer to the patchset. I think you're confusing things. DT doesn't contain the boot alias memory ranges - it's not a separate chunk of memory. It's an alias of the same physical address space found higher in the physical address range. If we put it in DT, then we need a way to also describe that it is an alias of some other bit of physical memory. -- RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up according to speedtest.net.
