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

AKASHI Takahiro
2020-03-31T23:57:33Z

On Tue, Mar 31, 2020 at 03:08:06PM +0200, Heinrich Schuchardt wrote:
> On 2020-03-31 09:44, AKASHI Takahiro wrote:
> > 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.
>
> Hello Akashi,
>
> without FAT_WRITE we will not have persistence for variables.
> SetVariable and GetVariable are still usable.

How about CONFIG_FAT?

-Takahiro Akashi

> Best regards
>
> Heinrich
>
> >
> >>>
> >>> In addition, why do you treat FAT specifically here?
> >>> I remember that you insisted that other file system should be
> >>> allowed on U-Boot when I posted some patch.
> >>
> >> An EFI system partition is always FAT formatted. So if we want to safe
> >> U-Boot variables to the EFI system partition we require FAT.
> >
> > As system partition is required to be in FAT, file system used on
> > other partitions must also be in FAT since, as I said before,
> > UEFI specification clearly defines its file system format based on FAT.
> > See section 13.3.
> >
> > So,
> >
> >>> I remember that you insisted that other file system should be
> >>> allowed on U-Boot when I posted some patch.
> >
> > You reverted your statement above here.
> > That is my point.
> >
> > -Takahiro Akashi
> >
> >> Best regards
> >>
> >> Heinrich
> >>
> >>>
> >>> -Takahiro Akashi
> >>>
> >>>
> >>>> imply USB_KEYBOARD_FN_KEYS
> >>>> imply VIDEO_ANSI
> >>>> help
> >>>> --
> >>>> 2.25.1
>