[PATCH] powerpc/64: Make VDSO32 track COMPAT on 64-bit

[Christophe Leroy]

Le 08/09/2020 à 14:58, Michael Ellerman a écrit :
> When we added the VDSO32 kconfig symbol, which controls building of
> the 32-bit VDSO, we made it depend on CPU_BIG_ENDIAN (for 64-bit).
> 
> That was because back then COMPAT was always enabled for 64-bit, so
> depending on it would have left the 32-bit VDSO always enabled, which
> we didn't want.
> 
> But since then we have made COMPAT selectable, and off by default for
> ppc64le, so VDSO32 should really depend on that.
> 
> For most people this makes no difference, none of the defconfigs
> change, it's only if someone is building ppc64le with COMPAT=y, they
> will now also get VDSO32. If they've enabled COMPAT in order to run
> 32-bit binaries they presumably also want the 32-bit VDSO.
> 
> Signed-off-by: Michael Ellerman <mpe at ellerman.id.au>


Reviewed-by: Christophe Leroy <christophe.leroy at csgroup.eu>

Michael, please note that christophe.leroy at c-s.fr is a deprecated 
address that will one day not work anymore. Please use the new one 
whenever possible.

Christophe


> ---
>   arch/powerpc/platforms/Kconfig.cputype | 7 +++----
>   1 file changed, 3 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/powerpc/platforms/Kconfig.cputype b/arch/powerpc/platforms/Kconfig.cputype
> index 87737ec86d39..a80ad0ef436e 100644
> --- a/arch/powerpc/platforms/Kconfig.cputype
> +++ b/arch/powerpc/platforms/Kconfig.cputype
> @@ -490,13 +490,12 @@ endmenu
>   
>   config VDSO32
>   	def_bool y
> -	depends on PPC32 || CPU_BIG_ENDIAN
> +	depends on PPC32 || COMPAT
>   	help
>   	  This symbol controls whether we build the 32-bit VDSO. We obviously
>   	  want to do that if we're building a 32-bit kernel. If we're building
> -	  a 64-bit kernel then we only want a 32-bit VDSO if we're building for
> -	  big endian. That is because the only little endian configuration we
> -	  support is ppc64le which is 64-bit only.
> +	  a 64-bit kernel then we only want a 32-bit VDSO if we're also enabling
> +	  COMPAT.
>   
>   choice
>   	prompt "Endianness selection"
>