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Date:   Mon, 15 Aug 2022 14:36:26 -0700
From:   Eric Biggers <ebiggers@kernel.org>
To:     Robert Elliott <elliott@hpe.com>
Cc:     herbert@gondor.apana.org.au, davem@davemloft.net,
        linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org,
        toshi.kani@hpe.com
Subject: Re: [PATCH 8/8] crypto: Kconfig - sort the ciphers
Message-ID: <Yvq8Whax+i2jmQZJ@sol.localdomain>
References: <20220815190608.47182-1-elliott@hpe.com>
 <20220815190608.47182-9-elliott@hpe.com>
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On Mon, Aug 15, 2022 at 02:06:08PM -0500, Robert Elliott wrote:
> Sort the entries in Ciphers by their displayed names.
> In particular, keep the optimized CPU implementations next to the
> generic implementations.
> 
> Signed-off-by: Robert Elliott <elliott@hpe.com>
> ---
>  crypto/Kconfig | 118 ++++++++++++++++++++++++-------------------------
>  1 file changed, 59 insertions(+), 59 deletions(-)
> 
> diff --git a/crypto/Kconfig b/crypto/Kconfig
> index f5cfb73e2423..03f4e2d97ef9 100644
> --- a/crypto/Kconfig
> +++ b/crypto/Kconfig
> @@ -1500,6 +1500,65 @@ menu "Ciphers"
>  
>  	  Processes eight blocks in parallel.
>  
> +config CRYPTO_CHACHA20
> +	tristate "ChaCha"
> +	select CRYPTO_LIB_CHACHA_GENERIC
> +	select CRYPTO_SKCIPHER
> +	help
> +	  The ChaCha20, XChaCha20, and XChaCha12 stream cipher algorithms
> +
> +	  ChaCha20 is a 256-bit high-speed stream cipher designed by Daniel J.
> +	  Bernstein and further specified in RFC7539 for use in IETF protocols.
> +	  This is the portable C implementation of ChaCha20.  See
> +	  https://cr.yp.to/chacha/chacha-20080128.pdf for further information.
> +
> +	  XChaCha20 is the application of the XSalsa20 construction to ChaCha20
> +	  rather than to Salsa20.  XChaCha20 extends ChaCha20's nonce length
> +	  from 64 bits (or 96 bits using the RFC7539 convention) to 192 bits,
> +	  while provably retaining ChaCha20's security.  See
> +	  https://cr.yp.to/snuffle/xsalsa-20081128.pdf for further information.
> +
> +	  XChaCha12 is XChaCha20 reduced to 12 rounds, with correspondingly
> +	  reduced security margin but increased performance.  It can be needed
> +	  in some performance-sensitive scenarios.
> +
> +config CRYPTO_CHACHA20_X86_64
> +	tristate "ChaCha (x86_64 with SSSE3/AVX2/AVX-512VL)"
> +	depends on X86 && 64BIT
> +	select CRYPTO_SKCIPHER
> +	select CRYPTO_LIB_CHACHA_GENERIC
> +	select CRYPTO_ARCH_HAVE_LIB_CHACHA
> +	help
> +	  ChaCha stream cipher algorithms
> +
> +	  Architecture: x86_64 using:
> +	  * SSSE3 (Supplemental SSE3)
> +	  * AVX2 (Advanced Vector Extensions 2)
> +	  * AVX-512VL (Advanced Vector Extensions-512VL)
> +
> +config CRYPTO_CHACHA_MIPS
> +	tristate "ChaCha (MIPS32r2)"
> +	depends on CPU_MIPS32_R2
> +	select CRYPTO_SKCIPHER
> +	select CRYPTO_ARCH_HAVE_LIB_CHACHA
> +	help
> +	  ChaCha stream cipher algorithms
> +
> +	  Architecture: MIPS32r2
> +
> +config CRYPTO_CHACHA_S390
> +	tristate "ChaCha20 (s390)"
> +	depends on S390
> +	select CRYPTO_SKCIPHER
> +	select CRYPTO_LIB_CHACHA_GENERIC
> +	select CRYPTO_ARCH_HAVE_LIB_CHACHA
> +	help
> +	  ChaCha20 stream cipher (RFC 7539)
> +
> +	  Architecture: s390
> +
> +	  It is available as of z13.

Do we want to keep the architecture-specific options in crypto/Kconfig?  arm and
arm64 split them out into a separate file arch/$arch/crypto/Kconfig.  Perhaps
the other architectures should adopt that?

- Eric