[PATCH 09/16] efi_loader: imply FAT, FAT_WRITE

Mark Kettenis
2020-03-31T08:20:17Z

> Date: Tue, 31 Mar 2020 16:44:34 +0900
> From: AKASHI Takahiro <takahiro.akashi@linaro.org>
>
> On Tue, Mar 31, 2020 at 08:44:02AM +0200, Heinrich Schuchardt wrote:
> > On March 31, 2020, 5:28 a.m. UTC Takahiro Akashi wrote:
> > > On Fri, Mar 27, 2020 at 06:27:53AM +0100, Heinrich Schuchardt wrote:
> > > > The UEFI spec requires support for the FAT file system.
> > > >
> > > > Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
> > > > ---
> > > > lib/efi_loader/Kconfig | 2 ++
> > > > 1 file changed, 2 insertions(+)
> > > >
> > > > diff --git a/lib/efi_loader/Kconfig b/lib/efi_loader/Kconfig
> > > > index 9890144d41..e10ca05549 100644
> > > > --- a/lib/efi_loader/Kconfig
> > > > +++ b/lib/efi_loader/Kconfig
> > > > @@ -15,6 +15,8 @@ config EFI_LOADER
> > > > select HAVE_BLOCK_DEVICE
> > > > select REGEX
> > > > imply CFB_CONSOLE_ANSI
> > > > + imply FAT
> > > > + imply FAT_WRITE
> > >
> > > Obviously, this *imply* doesn't enforce enabling FAT.
> > > If it is absolutely necessary, another measure should be taken.
> >
> > If somebody wants to minimize the U-Boot size it might be necessary to
> > do without FAT_WRITE or FAT support.
>
> If so, Get/SetVariable won't be supported even in boot time
> with your patch applied. It is not practical for almost all users.

I *strongly* disagree with that statement. Most users don't care
about U-Boot providing a full EFI implementation. They just want to
boot their OS. The basic EFI support in U-Boot is good enough for
that and for OpenBSD and some Linux distros on arm/arm64 this is the
only bootpath that works. If adding more code leads to board
maintainers disabling EFI support this isn't helpful.