Re: [PATCH v5 1/8] arch: enable relative relocations for arm64, power, x86, s390 and x86

[Ard Biesheuvel]

On 25 December 2017 at 21:05, Sam Ravnborg <sam@xxxxxxxxxxxx> wrote:
> Hi Ard.
>
> On Mon, Dec 25, 2017 at 08:54:33PM +0000, Ard Biesheuvel wrote:
>> Before updating certain subsystems to use place relative 32-bit
>> relocations in special sections, to save space  and reduce the
>> number of absolute relocations that need to be processed at runtime
>> by relocatable kernels, introduce the Kconfig symbol and define it
>> for some architectures that should be able to support and benefit
>> from it.
>>
>> Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
>> Cc: Will Deacon <will.deacon@xxxxxxx>
>> Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
>> Cc: Paul Mackerras <paulus@xxxxxxxxx>
>> Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
>> Cc: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
>> Cc: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
>> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
>> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
>> Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
>> Cc: x86@xxxxxxxxxx
>> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
>> ---
>>  arch/Kconfig                    | 10 ++++++++++
>>  arch/arm64/Kconfig              |  1 +
>
>>  arch/arm64/kernel/vmlinux.lds.S |  2 +-
> The change to arch/arm64/kernel/vmlinux.lds.S is
> not justified in the changelog.
> Did you add it by mistake?
>

No. The PREL32 support adds a __ADDRESSABLE() macro that emits code
into .discard.text, and on arm64, the EFI object sections get a .init
prefix so we need to discard .init.discard.* explicitly as well.

I will add this as a note.

Thanks,
Ard.