There is no requirement for how the expanded keys are stored
in memory. They are only accessed by asm routines. If keys
are stored directly with stxvd2x, they can be loaded directly
with lxvd2x.
This speeds up ppc64le key expansion and crypting a bit too.
POWER9 aes benchmark delta:
name old time/op new time/op delta
Encrypt 15.0ns ± 0% 13.0ns ± 0% -13.17%
Decrypt 14.6ns ± 0% 13.0ns ± 0% -11.02%
Expand 49.1ns ± 0% 45.1ns ± 0% -8.01%
name old time/op new time/op delta
AESCBCEncrypt1K 1.08µs ± 0% 1.08µs ± 0% -0.46%
AESCBCDecrypt1K 744ns ± 0% 562ns ± 0% -24.46%
Change-Id: I91f3cdc770a178aee849301e4e6aa5a4a517ad10
Reviewed-on: https://go-review.googlesource.com/c/go/+/405135 Reviewed-by: Ian Lance Taylor <iant@google.com>
Run-TryBot: Paul Murphy <murp@ibm.com>
TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Lynn Boger <laboger@linux.vnet.ibm.com> Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>