On Fri, Oct 31, 2014 at 07:52:09AM +0000, Dave Young wrote: > Hi Geoff > > I tested your patches. The macihne is using spin-table cpu enable method > so I tried maxcpus=1 as you suggested. > > There's below issues for me, thoughts? > > 1. For acpi booting there's no /proc/device-tree so kexec can not find dtb > to use. Are you absolutely certain of this? To use ACPI, you must have booted via EFI, as the only mechanism for finding the ACPI tables is via EFI. If booted via EFI, the stub will have created a stub DTB if there is no provided DTB, to pass the command line and pointers to EFI data structures. This stub DTB should be present in the usual place. Thanks, Mark.