This makes AES-GCM always constant-time on aarch64 (provided assembly is
enabled). Unlike vpaes, this does come at a binary size penalty of 1K
compared to the gcm_*_4bit version.
ABI testing already covered by GCMTest.ABI (GHASH_ASM_ARM covers both
OPENSSL_ARM and OPENSSL_AARCH64.)
Cortex-A53 (Raspberry Pi 3 Model B+)
Before:
Did 274000 AES-128-GCM (16 bytes) seal operations in 1003461us (273055.0 ops/sec): 4.4 MB/s
Did 53000 AES-128-GCM (256 bytes) seal operations in 1007689us (52595.6 ops/sec): 13.5 MB/s
Did 12000 AES-128-GCM (1350 bytes) seal operations in 1075908us (11153.4 ops/sec): 15.1 MB/s
Did 2068 AES-128-GCM (8192 bytes) seal operations in 1089037us (1898.9 ops/sec): 15.6 MB/s
After:
Did 298000 AES-128-GCM (16 bytes) seal operations in 1002917us (297133.3 ops/sec): 4.8 MB/s
Did 64000 AES-128-GCM (256 bytes) seal operations in 1001124us (63928.1 ops/sec): 16.4 MB/s
Did 14000 AES-128-GCM (1350 bytes) seal operations in 1015477us (13786.6 ops/sec): 18.6 MB/s
Did 2497 AES-128-GCM (8192 bytes) seal operations in 1057951us (2360.2 ops/sec): 19.3 MB/s
Bug: 265
Change-Id: I251bf0f2eae0578580bb14192755e5d8ff64cd14
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/35285
Reviewed-by: Adam Langley <agl@google.com>
d22578f366