On Thu, 4 Jun 2020 13:01:37 -0600
Chris Murphy <lists(a)colorremedies.com> wrote:
> Just following the conversation for information purposes, but I
have
> questions. If systemd-boot were to be used as boot service, could
> the hibernate image be written to /boot/efi in place of the kernel
> and initramfs, or in parallel? Would systemd-boot be able to use
> it? Would that satisfy the encrypted and signed requirements?
No to all sadly.
On Linux, neither GRUB or sd-boot directly consume the hibernation
image to perform resume. Bootloader and firmware based hibernation
resumption is found on Windows and macOS (there are many hibernation
implementations on Windows). On Linux, this is a kernel feature, so
the bootloader loads kernel and initramfs and boots normally; the
kernel uses a kernel parameter hint(s) to discover the location of the
hibernation image within swap. And voila.
I think the kernel does have code to support Intel Rapid Start. This
is a firmware based hibernation resume implementation, so first the
firmware must support it. But honestly have no idea if it works
exactly like it does on Windows. At least on Windows it requires a
dedicated partition expressly for the hibernation image. And the
firmware's Intel Rapid Start function is given a hint at hibernate
time so i knows at next power on that it should resume from this
hibernation image directly.
Anyway, it would take work to build a generic implementation supported
in either bootloader.
Thanks for the information. Too bad.