Re: [PATCH] powerpc: define __LITTLE_ENDIAN and __BIG_ENDIAN for math-emu

[David Laight]

On Sun, 17 May 2026 12:14:21 +0800
Mingcong Bai <jeffbai@xxxxxxx> wrote:

> Similar to commit b929926f01f2 ("sh: define __BIG_ENDIAN for math-emu"),
> define __LITTLE_ENDIAN and __BIG_ENDIAN as 0 to mitigate build-time
> warnings:
> 
>   ./include/math-emu/double.h:59:21: error: ‘__BIG_ENDIAN’ is not defined, evaluates to ‘0’ [-Werror=undef]
>      59 | #if __BYTE_ORDER == __BIG_ENDIAN
>         |
> 
> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: 13da9e200fe4 ("Revert "endian: #define __BYTE_ORDER"")
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
> Closes: https://lore.kernel.org/oe-kbuild-all/202507301656.7FEX6J5W-lkp@xxxxxxxxx/
> Signed-off-by: Mingcong Bai <jeffbai@xxxxxxx>
> ---
>  arch/powerpc/include/asm/sfp-machine.h | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/powerpc/include/asm/sfp-machine.h b/arch/powerpc/include/asm/sfp-machine.h
> index 8b957aabb826d..db8525605c026 100644
> --- a/arch/powerpc/include/asm/sfp-machine.h
> +++ b/arch/powerpc/include/asm/sfp-machine.h
> @@ -319,10 +319,12 @@
>  #define abort()								\
>  	return 0
>  
> -#ifdef __BIG_ENDIAN
> +#ifdef __BIG_ENDIAN__
>  #define __BYTE_ORDER __BIG_ENDIAN
> +#define __LITTLE_ENDIAN 0
>  #else
>  #define __BYTE_ORDER __LITTLE_ENDIAN
> +#define __BIG_ENDIAN 0
>  #endif

I thought the expected/correct value for __BYTE_ORDER__ was either 1234 or 4321.
(apart from pdp11's 2143).

-- David

>  
>  /* Exception flags. */