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

[Babu Moger]

On 5/25/2017 5:27 PM, Max Filippov wrote:
> On Wed, May 24, 2017 at 3:18 AM, Arnd Bergmann <arnd@xxxxxxxx> wrote:
> > On Wed, May 24, 2017 at 11:59 AM, Geert Uytterhoeven
> > <geert@xxxxxxxxxxxxxx> wrote:
> > > I guess the time is ripe for adding (both) symbols to all architectures?
> > Good idea. I think we can do most of this by adding a few lines to
> > arch/Kconfig:
> >
> > config CPU_BIG_ENDIAN
> >          bool
> >
> > config CPU_LITTLE_ENDIAN
> >         def_bool !CPU_BIG_ENDIAN
> >
> > This way, we only need to add 'select CPU_BIG_ENDIAN' to the
> > architectures that are always big-endian, and we don't need to
> > change anything for the ones that have a single 'CPU_BIG_ENDIAN'
> > option.
> >
> > The three architectures that have a 'choice' statement (mips, ppc and
> > sh) will have to convert, and m32r will have to replace the
> > option with the opposite one, which could break 'make oldconfig',
> > but nobody really cares about m32r any more.
> 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?