On 05/11/16 at 09:52am, Russell King - ARM Linux wrote: > 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. Hmm, if we forget about kexec how does the 1st kernel get boot memory? not from DT? > > 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. I may missed the background, I just want kexec to get infomation just like the normal kernel. > > -- > 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. Thanks Dave -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
