From: ebiggers3@gmail.com (Eric Biggers)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] crypto: arm/chacha20 - always use vrev for 16-bit rotates
Date: Tue, 24 Jul 2018 18:29:07 -0700 [thread overview]
Message-ID: <20180725012907.1614-1-ebiggers3@gmail.com> (raw)
From: Eric Biggers <ebiggers@google.com>
The 4-way ChaCha20 NEON code implements 16-bit rotates with vrev32.16,
but the one-way code (used on remainder blocks) implements it with
vshl + vsri, which is slower. Switch the one-way code to vrev32.16 too.
Signed-off-by: Eric Biggers <ebiggers@google.com>
---
arch/arm/crypto/chacha20-neon-core.S | 10 ++++------
1 file changed, 4 insertions(+), 6 deletions(-)
diff --git a/arch/arm/crypto/chacha20-neon-core.S b/arch/arm/crypto/chacha20-neon-core.S
index 3fecb2124c35..451a849ad518 100644
--- a/arch/arm/crypto/chacha20-neon-core.S
+++ b/arch/arm/crypto/chacha20-neon-core.S
@@ -51,9 +51,8 @@ ENTRY(chacha20_block_xor_neon)
.Ldoubleround:
// x0 += x1, x3 = rotl32(x3 ^ x0, 16)
vadd.i32 q0, q0, q1
- veor q4, q3, q0
- vshl.u32 q3, q4, #16
- vsri.u32 q3, q4, #16
+ veor q3, q3, q0
+ vrev32.16 q3, q3
// x2 += x3, x1 = rotl32(x1 ^ x2, 12)
vadd.i32 q2, q2, q3
@@ -82,9 +81,8 @@ ENTRY(chacha20_block_xor_neon)
// x0 += x1, x3 = rotl32(x3 ^ x0, 16)
vadd.i32 q0, q0, q1
- veor q4, q3, q0
- vshl.u32 q3, q4, #16
- vsri.u32 q3, q4, #16
+ veor q3, q3, q0
+ vrev32.16 q3, q3
// x2 += x3, x1 = rotl32(x1 ^ x2, 12)
vadd.i32 q2, q2, q3
--
2.18.0
next reply other threads:[~2018-07-25 1:29 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-25 1:29 Eric Biggers [this message]
2018-07-25 6:18 ` [PATCH] crypto: arm/chacha20 - always use vrev for 16-bit rotates Ard Biesheuvel
2018-08-03 13:59 ` Herbert Xu
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20180725012907.1614-1-ebiggers3@gmail.com \
--to=ebiggers3@gmail.com \
--cc=linux-arm-kernel@lists.infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).