[U-Boot] [PATCH 0/4] efi_loader: non-volatile variables support

[Takahiro Akashi]

# My patch is more or less a RFC to raise attention.

On Wed, Dec 05, 2018 at 11:53:42AM +0530, Sumit Garg wrote:
> Hi Akashi,
> 
> On Wed, 28 Nov 2018 at 11:28, AKASHI Takahiro
> <takahiro.akashi at linaro.org> wrote:
> >
> > As the subject suggested, this patch set allows any efi variable to be
> > volatile or non-volatile as UEFI specification describes.
> >
> > With my efishell patch[1] with patch #2, you can try as follows:
> >   => efi setvar PlatformLang en
> >   => efi setvar -nv BootNext =H0200
> >   => env save
> >
> 
> How do you expect usage of "EFI_VARIABLE_NON_VOLATILE" attribute to
> work during boot-time services as we don't have "env save" command
> option as a boot-time service?
> 
> Take example scenario with EDK2 shell launched from u-boot and tries
> to set non-volatile efi variable.

I know the issue, but

> IMHO, support should be added to "efi_set_variable" to save variable
> with "EFI_VARIABLE_NON_VOLATILE" attribute to non volatile storage.

I also hesitate to implement such a behavior to efi_set_variable
as it ends up writing to flash every time. Please note that data on
storage is a sorted list in plain text and so updating it can be painful.

-Takahiro Akashi


> -Sumit
> 
> > BootNext will be preserved across reboot, while PlatformLang not.
> >
> > Please note that, currently, setvar command does not automatically
> > append NON_VOLATILE attribute, while UEFI specification expects that
> > PlatformLang be non-volatile, you'd better also specify -nv for
> > this variable here.
> >
> > Patch #2/#3 depend on my efishell patch[1].
> > Patch #4 depends on my BootNext patch[2].
> >
> > Patch[1] and [2] have not been merged yet, so patch#1 can be applied
> > on its own.
> >
> > [1] https://lists.denx.de/pipermail/u-boot/2018-November/346450.html
> > [2] https://lists.denx.de/pipermail/u-boot/2018-November/349281.html
> >
> > AKASHI Takahiro (4):
> >   efi_loader: support non-volatile variable behavior
> >   cmd: efishell: support -nv option to setvar sub-command
> >   cmd: efishell: make Boot####/BootOrder variable non-volatile
> >   efi_loader: bootmgr: make BootNext non-volatile
> >
> >  cmd/efishell.c                | 20 ++++++++---
> >  env/env.c                     |  4 +++
> >  include/efi_loader.h          |  1 +
> >  lib/efi_loader/efi_bootmgr.c  |  3 +-
> >  lib/efi_loader/efi_variable.c | 64 +++++++++++++++++++++++++++++++++--
> >  5 files changed, 84 insertions(+), 8 deletions(-)
> >
> > --
> > 2.19.1
> >
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