[v3,03/28] arm64: efi: Add missing Kconfig dependency on KERNEL_MODE_NEON

  The EFI runtime services ABI permits calls to EFI to clobber
certain FPSIMD/NEON registers, as per the AArch64 procedure call
standard.

Saving/restoring the clobbered registers around such calls needs
KERNEL_MODE_NEON, but the dependency is missing from Kconfig.

This patch adds the missing dependency.

This will aid bisection of the patches implementing support for the
ARM Scalable Vector Extension (SVE).

Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
---
 arch/arm64/Kconfig | 1 +
 1 file changed, 1 insertion(+)
  

On Tue, Oct 10, 2017 at 07:38:20PM +0100, Dave P Martin wrote:
> The EFI runtime services ABI permits calls to EFI to clobber
> certain FPSIMD/NEON registers, as per the AArch64 procedure call
> standard.
> 
> Saving/restoring the clobbered registers around such calls needs
> KERNEL_MODE_NEON, but the dependency is missing from Kconfig.
> 
> This patch adds the missing dependency.
> 
> This will aid bisection of the patches implementing support for the
> ARM Scalable Vector Extension (SVE).
> 
> Signed-off-by: Dave Martin <Dave.Martin@arm.com>
> Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
> ---
>  arch/arm64/Kconfig | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index 0df64a6..ca711ac 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -1063,6 +1063,7 @@ config EFI_STUB
>  config EFI
>  	bool "UEFI runtime support"
>  	depends on OF && !CPU_BIG_ENDIAN
> +	depends on KERNEL_MODE_NEON
>  	select LIBFDT
>  	select UCS2_STRING
>  	select EFI_PARAMS_FROM_FDT

We could've used select KERNEL_MODE_NEON since it's a feature needed by
EFI but this works for me as well as KERNEL_MODE_NEON is def_bool y
already. Either way:

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
  

On Wed, Oct 11, 2017 at 03:16:47PM +0100, Catalin Marinas wrote:
> On Tue, Oct 10, 2017 at 07:38:20PM +0100, Dave P Martin wrote:
> > The EFI runtime services ABI permits calls to EFI to clobber
> > certain FPSIMD/NEON registers, as per the AArch64 procedure call
> > standard.
> > 
> > Saving/restoring the clobbered registers around such calls needs
> > KERNEL_MODE_NEON, but the dependency is missing from Kconfig.
> > 
> > This patch adds the missing dependency.
> > 
> > This will aid bisection of the patches implementing support for the
> > ARM Scalable Vector Extension (SVE).
> > 
> > Signed-off-by: Dave Martin <Dave.Martin@arm.com>
> > Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
> > ---
> >  arch/arm64/Kconfig | 1 +
> >  1 file changed, 1 insertion(+)
> > 
> > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> > index 0df64a6..ca711ac 100644
> > --- a/arch/arm64/Kconfig
> > +++ b/arch/arm64/Kconfig
> > @@ -1063,6 +1063,7 @@ config EFI_STUB
> >  config EFI
> >  	bool "UEFI runtime support"
> >  	depends on OF && !CPU_BIG_ENDIAN
> > +	depends on KERNEL_MODE_NEON
> >  	select LIBFDT
> >  	select UCS2_STRING
> >  	select EFI_PARAMS_FROM_FDT
> 
> We could've used select KERNEL_MODE_NEON since it's a feature needed by
> EFI but this works for me as well as KERNEL_MODE_NEON is def_bool y
> already. Either way:
> 
> Acked-by: Catalin Marinas <catalin.marinas@arm.com>

Agreed.  I assumed this is moot anyway, since KERNEL_MODE_NEON will
rarely/never be deselected in practice.

Cheers
---Dave