Re: [RFC V1 1/7] x86: Probe assembler capabilities for VAES and VPLCMULQDQ support

[Ard Biesheuvel <ardb@kernel.org>]

On Fri, 18 Dec 2020 at 22:07, Megha Dey <megha.dey@intel.com> wrote:
>
> This is a preparatory patch to introduce the optimized crypto algorithms
> using AVX512 instructions which would require VAES and VPLCMULQDQ support.
>
> Check for VAES and VPCLMULQDQ assembler support using AVX512 registers.
>
> Cc: x86@kernel.org
> Signed-off-by: Megha Dey <megha.dey@intel.com>
> ---
>  arch/x86/Kconfig.assembler | 10 ++++++++++
>  1 file changed, 10 insertions(+)
>
> diff --git a/arch/x86/Kconfig.assembler b/arch/x86/Kconfig.assembler
> index 26b8c08..9ea0bc8 100644
> --- a/arch/x86/Kconfig.assembler
> +++ b/arch/x86/Kconfig.assembler
> @@ -1,6 +1,16 @@
>  # SPDX-License-Identifier: GPL-2.0
>  # Copyright (C) 2020 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
>
> +config AS_VAES_AVX512
> +       def_bool $(as-instr,vaesenc %zmm0$(comma)%zmm1$(comma)%zmm1) && 64BIT

Is the '&& 64BIT' necessary here, but not below?

In any case, better to use a separate 'depends on' line, for legibility

> +       help
> +         Supported by binutils >= 2.30 and LLVM integrated assembler
> +
> +config AS_VPCLMULQDQ
> +       def_bool $(as-instr,vpclmulqdq \$0$(comma)%zmm2$(comma)%zmm6$(comma)%zmm4)
> +       help
> +         Supported by binutils >= 2.30 and LLVM integrated assembler
> +
>  config AS_AVX512
>         def_bool $(as-instr,vpmovm2b %k1$(comma)%zmm5)
>         help
> --
> 2.7.4
>