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Subject: Re: [PATCH] efi/libstub/arm64: Enable __efistub_global define in
 .data section
To:     Ard Biesheuvel <ardb@kernel.org>
Cc:     linux-efi <linux-efi@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
References: <1586468669-21456-1-git-send-email-victor.erminpour@oracle.com>
 <CAMj1kXGgYYx=9rq-Ficw3vS6FX_0nb-hRStXijh7H4zdD=+Gaw@mail.gmail.com>
From:   Victor Erminpour <victor.erminpour@oracle.com>
Organization: Oracle America
Message-ID: <aee6c7cc-24c7-2822-47d5-1e05413a8024@oracle.com>
Date:   Fri, 10 Apr 2020 15:12:13 -0700
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On 4/10/20 1:09 AM, Ard Biesheuvel wrote:
> On Thu, 9 Apr 2020 at 23:44, Victor Erminpour
> <victor.erminpour@oracle.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


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.


Regards,
--Victor


> 
>> Signed-off-by: Victor Erminpour <victor.erminpour@oracle.com>
>> ---
>>   drivers/firmware/efi/libstub/efistub.h | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/firmware/efi/libstub/efistub.h b/drivers/firmware/efi/libstub/efistub.h
>> index c244b16..59932d6 100644
>> --- a/drivers/firmware/efi/libstub/efistub.h
>> +++ b/drivers/firmware/efi/libstub/efistub.h
>> @@ -25,7 +25,7 @@
>>   #define EFI_ALLOC_ALIGN                EFI_PAGE_SIZE
>>   #endif
>>
>> -#ifdef CONFIG_ARM
>> +#if defined(CONFIG_ARM) || defined(CONFIG_ARM64)
>>   #define __efistub_global       __section(.data)
>>   #else
>>   #define __efistub_global

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