Request for more information

[patrickdepinguin]

The readme only mentions "A simple kexec for flattened device tree platforms, on PowerPC."
Can you clarify how it is simpler (what are the problems with kexec) and what the restrictions are?
Why would someone choose kexec-lite over kexec?

Is this supposed to work for all powerpc systems, also embedded ones?

What are the restrictions for other architectures (which meanwhile also support FDT). Is it a matter of implementing support for it, or are there technical limitations why that is not possible?

[oohal]

The readme only mentions "A simple kexec for flattened device tree platforms, on PowerPC."
Can you clarify how it is simpler (what are the problems with kexec) and what the restrictions are?
Why would someone choose kexec-lite over kexec?

Size primarily. On Power 8 servers we use a buildroot based linux environment as our boot loader rather than uBoot or GRUB. We only have ~16MB available for the kernel and root filesystem image so space is at a premium and some very unscientific testing shows kexec-lite compiles to ~32Kb compared to 200Kb for kexec-tools.

Is this supposed to work for all powerpc systems, also embedded ones?

What are the restrictions for other architectures (which meanwhile also support FDT). Is it a matter of implementing support for it, or are there technical limitations why that is not possible?

There's no reason it can't work in other environments, but I don't think anyone has really tried. At the very least some work would be required to adapt it to the kernel formats of other platforms since we only support kexec()ing into a vmlinux (i.e uncompressed) image. If there's interest in using it elsewhere let me know and I'll look into it.