Re: [OE-core] [PATCH v3 01/11] systemd: enable efi support by default

[Mikko Rapeli <mikko.rapeli@linaro.org>]

Hi,

First, Sorry for the email address mixup with Adrian, mutt
bounce did unexpected things.

On Thu, Apr 10, 2025 at 04:51:51PM +0200, Alexander Kanavin wrote:
> On Thu, 10 Apr 2025 at 16:39, Ilias Apalodimas
> <ilias.apalodimas@linaro.org> wrote:
> > I am going to assume that by 'boards' we mostly target embedded ones right?
> > The majority of those work with U-Boot which has a pretty capable EFI
> > implementation nowadays and supports a variety of filesystems.
> >
> > P.S: I am pretty sure that EDK2 and servers support more filesystems
> > than just FAT, but I can double check.
> 
> We're talking about UEFI firmware, right? The thing that reads the
> bootloader from ESP/ on storage and runs it. Is u-boot or ovmf used to
> implement that? It's that firmware that I have scepticism about, not
> the bootloaders.

There are multiple levels of bootloaders. From HW to first ones in
CPU SW/firmware, multiple levels inside and implementing UEFI and then
ones using UEFI interfaces to load operating systems.

We're talking about the ones which implement UEFI and edk2 and u-boot are the
most popular ones. ovmf is based on edk2, as are many SoC vendor firmware
implementations. Default qemu builds of u-boot also implement UEFI which we use
in oe-core to boot wic images with an ESP partition which then hosts
grub or systemd-boot OS loaders, config files, kernel, initramfs and/or
UKI binaries.

Hope this helps,

-Mikko