Enable vpaes for aarch64, with CTR optimizations.

This patches vpaes-armv8.pl to add vpaes_ctr32_encrypt_blocks. CTR mode
is by far the most important mode these days. It should have access to
_vpaes_encrypt_2x, which gives a considerable speed boost. Also exclude
vpaes_ecb_* as they're not even used.

For iOS, this change is completely a no-op. iOS ARMv8 always has crypto
extensions, and we already statically drop all other AES

Android ARMv8 is *not* required to have crypto extensions, but every
ARMv8 device I've seen has them. For those, it is a no-op
performance-wise and a win on size. vpaes appears to be about 5.6KiB
smaller than the tables. ARMv8 always makes SIMD (NEON) available, so we
can statically drop aes_nohw.

In theory, however, crypto-less Android ARMv8 is possible. Today such
chips get a variable-time AES. This CL fixes this, but the performance
story is complex.

The Raspberry Pi 3 is not Android but has a Cortex-A53 chip
without crypto extensions. (But the official images are 32-bit, so even
this is slightly artificial...) There, vpaes is a performance win.

Raspberry Pi 3, Model B+, Cortex-A53
Did 265000 AES-128-GCM (16 bytes) seal operations in 1003312us (264125.2 ops/sec): 4.2 MB/s
Did 44000 AES-128-GCM (256 bytes) seal operations in 1002141us (43906.0 ops/sec): 11.2 MB/s
Did 9394 AES-128-GCM (1350 bytes) seal operations in 1032104us (9101.8 ops/sec): 12.3 MB/s
Did 1562 AES-128-GCM (8192 bytes) seal operations in 1008982us (1548.1 ops/sec): 12.7 MB/s
Did 277000 AES-128-GCM (16 bytes) seal operations in 1001884us (276479.1 ops/sec): 4.4 MB/s
Did 52000 AES-128-GCM (256 bytes) seal operations in 1001480us (51923.2 ops/sec): 13.3 MB/s
Did 11000 AES-128-GCM (1350 bytes) seal operations in 1007979us (10912.9 ops/sec): 14.7 MB/s
Did 2013 AES-128-GCM (8192 bytes) seal operations in 1085545us (1854.4 ops/sec): 15.2 MB/s

The Pixel 3 has a Cortex-A75 with crypto extensions, so it would never
run this code. However, artificially ignoring them gives another data
point (ARM documentation[*] suggests the extensions are still optional
on a Cortex-A75.) Sadly, vpaes no longer wins on perf over aes_nohw.
But, it is constant-time:

Pixel 3, AES/PMULL extensions ignored, Cortex-A75:
Did 2102000 AES-128-GCM (16 bytes) seal operations in 1000378us (2101205.7 ops/sec): 33.6 MB/s
Did 358000 AES-128-GCM (256 bytes) seal operations in 1002658us (357051.0 ops/sec): 91.4 MB/s
Did 75000 AES-128-GCM (1350 bytes) seal operations in 1012830us (74049.9 ops/sec): 100.0 MB/s
Did 13000 AES-128-GCM (8192 bytes) seal operations in 1036524us (12541.9 ops/sec): 102.7 MB/s
Did 1453000 AES-128-GCM (16 bytes) seal operations in 1000213us (1452690.6 ops/sec): 23.2 MB/s
Did 285000 AES-128-GCM (256 bytes) seal operations in 1002227us (284366.7 ops/sec): 72.8 MB/s
Did 60000 AES-128-GCM (1350 bytes) seal operations in 1016106us (59049.0 ops/sec): 79.7 MB/s
Did 11000 AES-128-GCM (8192 bytes) seal operations in 1094184us (10053.2 ops/sec): 82.4 MB/s

Note the numbers above run with PMULL off, so the slow GHASH is
dampening the regression. If we test aes_nohw and vpaes paired with
PMULL on, the 20% perf hit becomes a 31% hit. The PMULL-less variant is
more likely to represent a real chip.

This is consistent with upstream's note in the comment, though it is
unclear if 20% is the right order of magnitude: "these results are worse
than scalar compiler-generated code, but it's constant-time and
therefore preferred".

[*] http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.100458_0301_00_en/lau1442495529696.html

Bug: 246
Change-Id: If1dc87f5131fce742052498295476fbae4628dbf
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/35026
Commit-Queue: David Benjamin <davidben@google.com>
Reviewed-by: Adam Langley <agl@google.com>
5 files changed
tree: 7f70b3eb8acc979c4f15fc3cc3866c4e737337a3
  1. .clang-format
  2. .github/
  3. .gitignore
  6. BUILDING.md
  7. CMakeLists.txt
  9. FUZZING.md
  12. PORTING.md
  13. README.md
  14. STYLE.md
  15. codereview.settings
  16. crypto/
  17. decrepit/
  18. fipstools/
  19. fuzz/
  20. go.mod
  21. include/
  22. sources.cmake
  23. ssl/
  24. third_party/
  25. tool/
  26. util/


BoringSSL is a fork of OpenSSL that is designed to meet Google's needs.

Although BoringSSL is an open source project, it is not intended for general use, as OpenSSL is. We don't recommend that third parties depend upon it. Doing so is likely to be frustrating because there are no guarantees of API or ABI stability.

Programs ship their own copies of BoringSSL when they use it and we update everything as needed when deciding to make API changes. This allows us to mostly avoid compromises in the name of compatibility. It works for us, but it may not work for you.

BoringSSL arose because Google used OpenSSL for many years in various ways and, over time, built up a large number of patches that were maintained while tracking upstream OpenSSL. As Google's product portfolio became more complex, more copies of OpenSSL sprung up and the effort involved in maintaining all these patches in multiple places was growing steadily.

Currently BoringSSL is the SSL library in Chrome/Chromium, Android (but it's not part of the NDK) and a number of other apps/programs.

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