Re: -Wincompatible-pointer-types in arch/powerpc/platforms/embedded6xx/mvme5100.c

[Scott Wood <oss@buserror.net>]

On Tue, 2020-04-14 at 17:33 +1000, Michael Ellerman wrote:
> I'm not sure TBH. This is all ancient history as far as I can tell, none
> of it's been touched for ~7 years.
> 
> Your config has:
> 
> CONFIG_EMBEDDED6xx=y
> CONFIG_PPC_BOOK3S_32=y
> CONFIG_PPC_BOOK3S_6xx=y
> CONFIG_PPC_MPC52xx=y
> CONFIG_PPC_86xx=y
> 
> 
> Which I'm not sure really makes sense at all, ie. it's trying to build a
> kernel for multiple platforms at once (EMBEDDED6xx, MPC52xx, 86xx), but
> the Kconfig doesn't exclude that so I guess we have to live with it for
> now.

I thought supporting multiple platforms in a kernel was something we tried to
support when practical?

> So I'm going to guess it should have also excluded embedded6xx, and this
> seems to fix it:
> 
> diff --git a/arch/powerpc/platforms/Kconfig.cputype
> b/arch/powerpc/platforms/Kconfig.cputype
> index 0c3c1902135c..134fc383daf7 100644
> --- a/arch/powerpc/platforms/Kconfig.cputype
> +++ b/arch/powerpc/platforms/Kconfig.cputype
> @@ -278,7 +278,7 @@ config PTE_64BIT
>  
>  config PHYS_64BIT
>  	bool 'Large physical address support' if E500 || PPC_86xx
> -	depends on (44x || E500 || PPC_86xx) && !PPC_83xx && !PPC_82xx
> +	depends on (44x || E500 || PPC_86xx) && !PPC_83xx && !PPC_82xx &&
> !EMBEDDED6xx
>  	select PHYS_ADDR_T_64BIT
>  	---help---
>  	  This option enables kernel support for larger than 32-bit physical
> 
> 
> So unless anyone can tell me otherwise I'm inclined to commit that ^

This could silently break someone's config who's depending on PHYS_64BIT (e.g.
an 86xx kernel that happens to include an embedded6xx target as well, even if
just by accident).  It'd be better to have the MVME500 depend on
!CONFIG_PHYS_ADDR_T_64BIT as Nathan suggested (if there's nobody around to
test a fix to the actual bug), which shouldn't break anyone since it already
didn't build.

-Scott