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

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Date:   Mon, 13 Apr 2020 15:56:40 -0700
From:   Victor Erminpour <victor.erminpour@...cle.com>
To:     Ard Biesheuvel <ardb@...nel.org>,
        Arvind Sankar <nivedita@...m.mit.edu>
Cc:     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 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

> 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!

Regards,
--Victor


> 

-- 
Victor Hugo Erminpour
Principal Member of Technical Staff
Oracle America