linux-kernel - Re: [PATCH] efi/libstub/arm64: Enable __efistub

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Date:   Tue, 14 Apr 2020 08:46:01 +0200
From:   Ard Biesheuvel <ardb@...nel.org>
To:     Victor Erminpour <victor.erminpour@...cle.com>
Cc:     Arvind Sankar <nivedita@...m.mit.edu>,
        linux-efi <linux-efi@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] efi/libstub/arm64: Enable __efistub_global define in
 .data section

On Tue, 14 Apr 2020 at 00:57, Victor Erminpour
<victor.erminpour@...cle.com> wrote:
>
>
>
> On 4/10/20 11:39 PM, Ard Biesheuvel wrote:
> > On Sat, 11 Apr 2020 at 00:12, Victor Erminpour
> > <victor.erminpour@...cle.com> wrote:
> >>
> >>
> >>
> >> On 4/10/20 1:09 AM, Ard Biesheuvel wrote:
> >>> On Thu, 9 Apr 2020 at 23:44, Victor Erminpour
> >>> <victor.erminpour@...cle.com> wrote:
> >>>>
> >>>> Enable the __efistub_global define to place variables in the
> >>>> .data section for both CONFIG_ARM and CONFIG_ARM64.
> >>>>
> >>>> This places the EFIstub sys_table variable and other EFIstub
> >>>> static variables in the .data section for both CONFIG_ARM and
> >>>> CONFIG_ARM64.
> >>>>
> >>>
> >>> What does that achieve?
> >>
> >> Hi Ard,
> >>
> >> Without placing these global variables in .data, I get the
> >> following errors when booting an ARM64 EFI system:
> >>
> >> EFI stub: ERROR: Exit boot services failed.
> >> EFI stub: ERROR: Failed to update FDT and exit boot services
> >>
> >
> > Which boot loader are you using? Does this involve shim?
> >
>
> grub2-efi-aa64-2.02-0.80.0.4.el7.aarch64
> shim-aa64-15-1.0.4.el7.aarch64
>

Does your system give access to the UEFI shell? If so, could you
please try booting the [uncompressed] Image file from the command
prompt? Which hardware are you booting?

> > Also, does it help if you add 'efi=no_disable_early_pci_dma'?
> >
>
> Tried this boot time option, but to no effect.
>
> >
> >>
> >> I know that the ARM64 linker script is supposed to put the
> >> .init.bss into the .init.data section, but I don't think this
> >> is happening for all systems.
> >>
> >> Having it explicitly enabled for CONFIG_ARM64 worked for me.
> >>
> >
> > OK, thanks for the report. However, we will be removing
> > __efistub_global entirely during the next cycle, so this is not the
> > right fix.
>
> Thanks Ard, this sounds promising!
>

Quite the opposite, unfortunately. It means the feature you are using
to fix your boot issue is going away.

This really looks like a bootloader issue to me, so let's narrow this
down first. If there is a real kernel issue here that needs
__efistub_global to be fixed, we obviously won't be removing it.