On Thu, 2014-11-13 at 16:37 +0800, Dave Young wrote:

In your kexec-tools code, by default it will create dtb1 from procfs, as for external
--dtb it will be dtb2 for comparing with dtb1.

Since dtb1 is a must so it will not work without /proc/device-tree.

I changed that to allow for no /proc/device-tree if --dtb is passed
since it will also allow a kernel built with CONFIG_PROC_FS=n to do
kexec re-boot.

Please try it and let me know.

There had some discussion about this in the thread. But I think we have no
conclusion where to go.

There maybe below possibilities:
1) unflattern dtb both for EFI/acpi booting even if acpi boot does not need it.

2) copy the bootloader passed dtb stub to somewhere, and export the stub to
 userspace ie. in debugfs or procfs
 like /proc/saved_dtb 

Thoughts to continue the discuss?

Some progress has been made, let's see what they come up with.

-Geoff