linux-kernel - Re: [PATCH 3/3] arm64: configs: unset CPU_BIG

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Date:   Tue, 15 Oct 2019 11:13:05 +0800
From:   Hanjun Guo <guohanjun@...wei.com>
To:     Will Deacon <will@...nel.org>,
        Russell King - ARM Linux admin <linux@...linux.org.uk>
CC:     Anders Roxell <anders.roxell@...aro.org>,
        Arnd Bergmann <arnd@...db.de>,
        Catalin Marinas <catalin.marinas@....com>,
        John Garry <john.garry@...wei.com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Chunrong Guo <chunrong.guo@....com>,
        "Olof Johansson" <olof@...om.net>,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH 3/3] arm64: configs: unset CPU_BIG_ENDIAN

On 2019/10/15 0:24, Will Deacon wrote:
> On Sat, Oct 12, 2019 at 03:50:55PM +0100, Russell King - ARM Linux admin wrote:
>> On Sat, Oct 12, 2019 at 12:47:45AM +0200, Arnd Bergmann wrote:
>>> On Fri, Oct 11, 2019 at 12:33 PM Russell King - ARM Linux admin
>>> <linux@...linux.org.uk> wrote:
>>>> 32-bit ARM experience is that telco class users really like big
>>>> endian.
>>>
>>> Right, basically anyone with a large code base migrated over from a
>>> big-endian MIPS or PowerPC legacy that found it cheaper to change
>>> the rest of the world than to fix their own code.
>>
>> I think you need to step off your soap box!  Big endian isn't going
>> away, and it likely has nothing to do with code bases.  Just look at
>> networking and telco protocols.  Everything in that world tends to
>> be big endian.  BE is what is understood in that world, and there's
>> little we can do to change it.
>>
>> Demanding that they switch to LE is tantamount to you demanding that
>> their entire world change - it ain't going to happen.
> 
> Oh, I wasn't demanding anything! Just interested to know if big-endian is
> actually being used because it's not something that I'm able to test
> sensibly and I haven't see anywhere near the amount of (public) effort to
> keep it supported as for little-endian. However, having asked the question,
> it's clear that it does have some users so we'll keep maintaining it on a
> best-effort basis and rely on those users to let us know if anything breaks.

Sure, we (Huawei kernel team) did that and we will do that in the future
as well.

Thanks
Hanjun