Subject: Re: [PATCH v7 5/6] powerpc/64: Make COMPAT user-selectable disabled on littleendian by default.

From: Michael Ellerman <[email-masked]>
Date: Mon, 02 Sep 2019 12:03:12 +1000

Michal Suchanek <[email-masked]> writes:
> On bigendian ppc64 it is common to have 32bit legacy binaries but much
> less so on littleendian.

I think the toolchain people will tell you that there is no 32-bit
little endian ABI defined at all, if anything works it's by accident.

So I think we should not make this selectable, unless someone puts their
hand up to say they want it and are willing to test it and keep it
working.

cheers

> v3: make configurable
> ---
>  arch/powerpc/Kconfig | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
> index 5bab0bb6b833..b0339e892329 100644
> --- a/arch/powerpc/Kconfig
> +++ b/arch/powerpc/Kconfig
> @@ -264,8 +264,9 @@ config PANIC_TIMEOUT
>  	default 180
>  
>  config COMPAT
> -	bool
> -	default y if PPC64
> +	bool "Enable support for 32bit binaries"
> +	depends on PPC64
> +	default y if !CPU_LITTLE_ENDIAN
>  	select COMPAT_BINFMT_ELF
>  	select ARCH_WANT_OLD_COMPAT_IPC
>  	select COMPAT_OLD_SIGACTION
> -- 
> 2.22.0