Re: [PATCH 1/3] kexec: Prevent removal of memory in use by a loaded kexec image

[Dave Young <dyoung@redhat.com>]

> We do not remove kexec_load at all, it is indeed helpful in many cases
> as all agreed.  But if we have a bug reported for both we may fix
> kexec_file_load first because it is usually easier, also do not need to
> worry about too much about old kernel and new kernel compatibility.
> 
> For example the recent breakage we found in efi path, kexec_file_load
> just work after the efi cleanup, but kexec_load depends on the ABI we
> added, so we must fix it as below:
> https://lore.kernel.org/linux-efi/20200410135644.GB6772@dhcp-128-65.nay.redhat.com/ 

Also, we have some specific sysfs files exported for kexec-tools use
/sys/firmware/efi/runtime-map/* and a few other table addresses:
fw_vendor  runtime and config_table under /sys/firmware/efi

That is only used by userspace kexec_tools for kexec_load, now the
runtime field is useless because of Ard's cleanup in efi code, but we
have to keep it there, older kexec-tools will need it.

In this case kexec_file_load do not need those hacks at all.  So in the
future if we have to invent some kernel/userspace abi only for
kexec_load we should be careful and maybe reject if no strong reason. 

Thanks
Dave