Add a NEON-accelerated implementation of Speck128-XTS and Speck64-XTS
for ARM64. This is ported from the 32-bit version. It may be useful on
devices with 64-bit ARM CPUs that don't have the Cryptography
Extensions, so cannot do AES efficiently -- e.g. the Cortex-A53
processor on the Raspberry Pi 3.
It generally works the same way as the 32-bit version, but there are
some slight differences due to the different instructions, registers,
and syntax available in ARM64 vs. in ARM32. For example, in the 64-bit
version there are enough registers to hold the XTS tweaks for each
128-byte chunk, so they don't need to be saved on the stack.
Benchmarks on a Raspberry Pi 3 running a 64-bit kernel:
Algorithm Encryption Decryption
--------- ---------- ----------
Speck64/128-XTS (NEON) 92.2 MB/s 92.2 MB/s
Speck128/256-XTS (NEON) 75.0 MB/s 75.0 MB/s
Speck128/256-XTS (generic) 47.4 MB/s 35.6 MB/s
AES-128-XTS (NEON bit-sliced) 33.4 MB/s 29.6 MB/s
AES-256-XTS (NEON bit-sliced) 24.6 MB/s 21.7 MB/s
The code performs well on higher-end ARM64 processors as well, though
such processors tend to have the Crypto Extensions which make AES
preferred. For example, here are the same benchmarks run on a HiKey960
(with CPU affinity set for the A73 cores), with the Crypto Extensions
implementation of AES-256-XTS added:
Algorithm Encryption Decryption
--------- ----------- -----------
AES-256-XTS (Crypto Extensions) 1273.3 MB/s 1274.7 MB/s
Speck64/128-XTS (NEON) 359.8 MB/s 348.0 MB/s
Speck128/256-XTS (NEON) 292.5 MB/s 286.1 MB/s
Speck128/256-XTS (generic) 186.3 MB/s 181.8 MB/s
AES-128-XTS (NEON bit-sliced) 142.0 MB/s 124.3 MB/s
AES-256-XTS (NEON bit-sliced) 104.7 MB/s 91.1 MB/s
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Eric Biggers