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  1. 03 Feb, 2017 9 commits
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    • Ard Biesheuvel's avatar
      crypto: arm64/aes - reimplement bit-sliced ARM/NEON implementation for arm64 · 1abee99e
      Ard Biesheuvel authored 
      This is a reimplementation of the NEON version of the bit-sliced AES
algorithm. This code is heavily based on Andy Polyakov's OpenSSL version
for ARM, which is also available in the kernel. This is an alternative for
the existing NEON implementation for arm64 authored by me, which suffers
from poor performance due to its reliance on the pathologically slow four
register variant of the tbl/tbx NEON instruction.

This version is about ~30% (*) faster than the generic C code, but only in
cases where the input can be 8x interleaved (this is a fundamental property
of bit slicing). For this reason, only the chaining modes ECB, XTS and CTR
are implemented. (The significance of ECB is that it could potentially be
used by other chaining modes)

* Measured on Cortex-A57. Note that this is still an order of magnitude
  slower than the implementations that use the dedicated AES instructions
  introduced in ARMv8, but those are part of an optional extension, and so
  it is good to have a fallback.
Signed-off-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
      1abee99e
    • Ard Biesheuvel's avatar
      crypto: arm/aes - replace scalar AES cipher · 81edb426
      Ard Biesheuvel authored 
      This replaces the scalar AES cipher that originates in the OpenSSL project
with a new implementation that is ~15% (*) faster (on modern cores), and
reuses the lookup tables and the key schedule generation routines from the
generic C implementation (which is usually compiled in anyway due to
networking and other subsystems depending on it).

Note that the bit sliced NEON code for AES still depends on the scalar cipher
that this patch replaces, so it is not removed entirely yet.

* On Cortex-A57, the performance increases from 17.0 to 14.9 cycles per byte
  for 128-bit keys.
Signed-off-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
      81edb426
    • Ard Biesheuvel's avatar
      crypto: arm64/aes - add scalar implementation · bed593c0
      Ard Biesheuvel authored 
      This adds a scalar implementation of AES, based on the precomputed tables
that are exposed by the generic AES code. Since rotates are cheap on arm64,
this implementation only uses the 4 core tables (of 1 KB each), and avoids
the prerotated ones, reducing the D-cache footprint by 75%.

On Cortex-A57, this code manages 13.0 cycles per byte, which is ~34% faster
than the generic C code. (Note that this is still >13x slower than the code
that uses the optional ARMv8 Crypto Extensions, which manages <1 cycles per
byte.)
Signed-off-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
      bed593c0
    • Ard Biesheuvel's avatar
      crypto: arm64/aes-blk - expose AES-CTR as synchronous cipher as well · 293614ce
      Ard Biesheuvel authored 
      In addition to wrapping the AES-CTR cipher into the async SIMD wrapper,
which exposes it as an async skcipher that defers processing to process
context, expose our AES-CTR implementation directly as a synchronous cipher
as well, but with a lower priority.

This makes the AES-CTR transform usable in places where synchronous
transforms are required, such as the MAC802.11 encryption code, which
executes in sotfirq context, where SIMD processing is allowed on arm64.
Users of the async transform will keep the existing behavior.
Signed-off-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
      293614ce
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