linux-kernel - Re: CPU_BIG_ENDIAN in generic code (was: Re: [PATCH v3 3/7] arch/sparc: Define config parameter CPU_BIG

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Date:   Thu, 25 May 2017 15:52:14 -0700
From:   Max Filippov <jcmvbkbc@...il.com>
To:     Babu Moger <babu.moger@...cle.com>
Cc:     Arnd Bergmann <arnd@...db.de>,
        Geert Uytterhoeven <geert@...ux-m68k.org>,
        "David S. Miller" <davem@...emloft.net>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        sparclinux <sparclinux@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Linux-Arch <linux-arch@...r.kernel.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "linux-serial@...r.kernel.org" <linux-serial@...r.kernel.org>
Subject: Re: CPU_BIG_ENDIAN in generic code (was: Re: [PATCH v3 3/7]
 arch/sparc: Define config parameter CPU_BIG_ENDIAN)

On Thu, May 25, 2017 at 3:41 PM, Babu Moger <babu.moger@...cle.com> wrote:
> On 5/25/2017 5:27 PM, Max Filippov wrote:
>> Xtensa may have either endianness and for xtensa we define
>> CONFIG_CPU_BIG_ENDIAN or CONFIG_CPU_LITTLE_ENDIAN
>> in the arch/xtensa/Makefile based on the value of the compiler builtin
>> macro.
>
> Hmm.. That means defining  CPU_LITTLE_ENDIAN  based on "def_bool
> !CPU_BIG_ENDIAN" will
>  be a problem for Xtensa because menuconfig does not have the knowledge of
> compiler builtin macro.
> Is that correct?

I think so. OTOH outside the arch/ CPU_LITTLE_ENDIAN is only used in
two Kconfig files:

drivers/crypto/nx/Kconfig
drivers/isdn/hisax/Kconfig

both of which are irrelevant for xtensa.

-- 
Thanks.
-- Max