Re: EXT FS support

[Rod Smith <rodsmith@rodsbooks.com>]

On 11/22/2016 01:25 PM, Pete Batard wrote:
> On 2016.11.22 17:16, Marcin Wojtas wrote:
>> There's no GRUB, platform simply boots to the Shell.
> 
> I think there may be some confusion.
> 
> All the drivers we linked you to are pure UEFI drivers. It doesn't
> matter if they were a port from GRUB or something else, the code was
> converted to work as a standalone UEFI driver. Especially you don't need
> to have GRUB running or anything. You can just use the "load" command in
> the shell to load the driver, and then access the file system.
> 
> I believe you should be able to download any of the ext binary drivers
> mentioned and use them in your shell right away to access your file
> system from it.

Yes, but it sounds like Marcin may want to embed the ext4fs driver in a
custom EFI build. AFAIK, none of the drivers in question were designed
with that in mind; however, the VirtualBox project has incorporated
ISO-9660 and HFS+ drivers, both of which are built on the same framework
(rEFIt's) as rEFInd's drivers, into its own firmware. Thus, Marcin might
be able to look at the VirtualBox code and use whatever techniques or
glue it uses to incorporate something else. (I can't point to specific
files, though.) The rEFInd drivers might be easiest to build in this
way, but that's just a guess.

Note, however, that all of the drivers referenced so far in this thread
are licensed under the GPL. Thus, building an EFI in this way would
cause the EFI as a whole to be GPL-licensed. This might or might not be
an issue, depending on what the point of the exercise is.

Of course, a standalone driver might be perfectly acceptable, too. I've
seen options in some EFIs to load drivers at start time, but I've never
gotten them to work. (I haven't tried very hard.) If nothing else, a
small driver-loading program could be written and set as the first boot
option.

Marcin wrote:

> I also found this:
> https://sourceforge.net/p/cloverefiboot/code/HEAD/tree/FileSystems/VBoxFsDxe/

FWIW, that's a fork of the rEFInd code. I'd not seen it before now; the
Clover developers haven't bothered to upstream their changes. (I
maintain rEFInd.)

It's still not clear to me why you want this driver, Marcin. If you want
to load a Linux kernel directly, without using GRUB, rEFInd, or some
other tool, you can simply put the kernel(s) on a FAT filesystem. This
is a common approach among Arch Linux users; they mount the ESP at /boot
and it works pretty well. Some distributions assume that /boot supports
links or other features that aren't available with FAT, though, so maybe
this wouldn't work as well for you, but it's worth considering.

-- 
Rod Smith
rodsmith@rodsbooks.com
http://www.rodsbooks.com