Re: [PATCH] arm64: relax assembly code alignment from 16 byte to 4 byte

From: Masahiro Yamada
Date: Wed Sep 20 2017 - 06:59:34 EST


Hi Catalin,


2017-09-08 1:46 GMT+09:00 Catalin Marinas <catalin.marinas@xxxxxxx>:
> On Thu, Aug 31, 2017 at 06:56:23PM +0900, Masahiro Yamada wrote:
>> Aarch64 instructions must be word aligned. The current 16 byte
>> alignment is more than enough. Relax it into 4 byte alignment.
>>
>> Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
>> ---
>>
>> I do not know why arm64 Linux requires 16 byte alignment.
>>
>> I dug git-history of arch/arm64/include/asm/linkage.h
>> and the only commit I see is:
>>
>> commit aeed41a9371ee02257b608eb06a9058507a7d0f4
>> Author: Marc Zyngier <Marc.Zyngier@xxxxxxx>
>> Date: Fri Oct 19 17:33:27 2012 +0100
>>
>> arm64: fix alignment padding in assembly code
>>
>> It just opt out of the asm-generic variant to remove 0x90.
>> So, the amount of alignment might not be not optimized yet.
>>
>> Please correct me if I am missing something.
>
> Not sure why we ended up with 4. Possibly because we forgot the power of
> 2 difference for arm/arm64.
>
> Queued for 4.14. Thanks.


I still do not see this patch in linux-next.

Where was it queued?





--
Best Regards
Masahiro Yamada