Speed up the GHASH algorithm based on 64-bit polynomial multiplication
by adding support for 4-way aggregation. This improves throughput by
~85% on Cortex-A53, from 1.7 cycles per byte to 0.9 cycles per byte.
When combined with AES into GCM, throughput improves by ~25%, from
3.8 cycles per byte to 3.0 cycles per byte.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
---
v2: modulo schedule the loads of the input
add AES/GCM performance numbers to commit log
arch/arm/crypto/Kconfig | 1 +
arch/arm/crypto/ghash-ce-core.S | 108 +++++++++++++++++++-
arch/arm/crypto/ghash-ce-glue.c | 38 +++++--
3 files changed, 131 insertions(+), 16 deletions(-)
diff --git a/arch/arm/crypto/Kconfig b/arch/arm/crypto/Kconfig
index 925d1364727a..07dd12efeea4 100644
--- a/arch/arm/crypto/Kconfig
+++ b/arch/arm/crypto/Kconfig
@@ -99,6 +99,7 @@ config CRYPTO_GHASH_ARM_CE
depends on KERNEL_MODE_NEON
select CRYPTO_HASH
select CRYPTO_CRYPTD
+ select CRYPTO_GF128MUL
help
Use an implementation of GHASH (used by the GCM AEAD chaining mode)
that uses the 64x64 to 128 bit polynomial multiplication (vmull.p64)
diff --git a/arch/arm/crypto/ghash-ce-core.S b/arch/arm/crypto/ghash-ce-core.S
index 2f78c10b1881..406009afa9cf 100644
--- a/arch/arm/crypto/ghash-ce-core.S
+++ b/arch/arm/crypto/ghash-ce-core.S
@@ -63,6 +63,33 @@
k48 .req d31
SHASH2_p64 .req d31
+ HH .req q10
+ HH3 .req q11
+ HH4 .req q12
+ HH34 .req q13
+
+ HH_L .req d20
+ HH_H .req d21
+ HH3_L .req d22
+ HH3_H .req d23
+ HH4_L .req d24
+ HH4_H .req d25
+ HH34_L .req d26
+ HH34_H .req d27
+ SHASH2_H .req d29
+
+ XL2 .req q5
+ XM2 .req q6
+ XH2 .req q7
+ T3 .req q8
+
+ XL2_L .req d10
+ XL2_H .req d11
+ XM2_L .req d12
+ XM2_H .req d13
+ T3_L .req d16
+ T3_H .req d17
+
.text
.fpu crypto-neon-fp-armv8
@@ -175,12 +202,77 @@
beq 0f
vld1.64 {T1}, [ip]
teq r0, #0
- b 1f
+ b 3f
+
+0: .ifc \pn, p64
+ tst r0, #3 // skip until #blocks is a
+ bne 2f // round multiple of 4
+
+ vld1.8 {XL2-XM2}, [r2]!
+1: vld1.8 {T3-T2}, [r2]!
+ vrev64.8 XL2, XL2
+ vrev64.8 XM2, XM2
+
+ subs r0, r0, #4
+
+ vext.8 T1, XL2, XL2, #8
+ veor XL2_H, XL2_H, XL_L
+ veor XL, XL, T1
+
+ vrev64.8 T3, T3
+ vrev64.8 T1, T2
+
+ vmull.p64 XH, HH4_H, XL_H // a1 * b1
+ veor XL2_H, XL2_H, XL_H
+ vmull.p64 XL, HH4_L, XL_L // a0 * b0
+ vmull.p64 XM, HH34_H, XL2_H // (a1 + a0)(b1 + b0)
+
+ vmull.p64 XH2, HH3_H, XM2_L // a1 * b1
+ veor XM2_L, XM2_L, XM2_H
+ vmull.p64 XL2, HH3_L, XM2_H // a0 * b0
+ vmull.p64 XM2, HH34_L, XM2_L // (a1 + a0)(b1 + b0)
+
+ veor XH, XH, XH2
+ veor XL, XL, XL2
+ veor XM, XM, XM2
+
+ vmull.p64 XH2, HH_H, T3_L // a1 * b1
+ veor T3_L, T3_L, T3_H
+ vmull.p64 XL2, HH_L, T3_H // a0 * b0
+ vmull.p64 XM2, SHASH2_H, T3_L // (a1 + a0)(b1 + b0)
+
+ veor XH, XH, XH2
+ veor XL, XL, XL2
+ veor XM, XM, XM2
+
+ vmull.p64 XH2, SHASH_H, T1_L // a1 * b1
+ veor T1_L, T1_L, T1_H
+ vmull.p64 XL2, SHASH_L, T1_H // a0 * b0
+ vmull.p64 XM2, SHASH2_p64, T1_L // (a1 + a0)(b1 + b0)
+
+ veor XH, XH, XH2
+ veor XL, XL, XL2
+ veor XM, XM, XM2
-0: vld1.64 {T1}, [r2]!
+ beq 4f
+
+ vld1.8 {XL2-XM2}, [r2]!
+
+ veor T1, XL, XH
+ veor XM, XM, T1
+
+ __pmull_reduce_p64
+
+ veor T1, T1, XH
+ veor XL, XL, T1
+
+ b 1b
+ .endif
+
+2: vld1.64 {T1}, [r2]!
subs r0, r0, #1
-1: /* multiply XL by SHASH in GF(2^128) */
+3: /* multiply XL by SHASH in GF(2^128) */
#ifndef CONFIG_CPU_BIG_ENDIAN
vrev64.8 T1, T1
#endif
@@ -193,7 +285,7 @@
__pmull_\pn XL, XL_L, SHASH_L, s1l, s2l, s3l, s4l @ a0 * b0
__pmull_\pn XM, T1_L, SHASH2_\pn @ (a1+a0)(b1+b0)
- veor T1, XL, XH
+4: veor T1, XL, XH
veor XM, XM, T1
__pmull_reduce_\pn
@@ -212,8 +304,14 @@
* struct ghash_key const *k, const char *head)
*/
ENTRY(pmull_ghash_update_p64)
- vld1.64 {SHASH}, [r3]
+ vld1.64 {SHASH}, [r3]!
+ vld1.64 {HH}, [r3]!
+ vld1.64 {HH3-HH4}, [r3]
+
veor SHASH2_p64, SHASH_L, SHASH_H
+ veor SHASH2_H, HH_L, HH_H
+ veor HH34_L, HH3_L, HH3_H
+ veor HH34_H, HH4_L, HH4_H
vmov.i8 MASK, #0xe1
vshl.u64 MASK, MASK, #57
diff --git a/arch/arm/crypto/ghash-ce-glue.c b/arch/arm/crypto/ghash-ce-glue.c
index 8930fc4e7c22..b7d30b6cf49c 100644
--- a/arch/arm/crypto/ghash-ce-glue.c
+++ b/arch/arm/crypto/ghash-ce-glue.c
@@ -1,7 +1,7 @@
/*
* Accelerated GHASH implementation with ARMv8 vmull.p64 instructions.
*
- * Copyright (C) 2015 Linaro Ltd. <ard.biesheuvel@xxxxxxxxxx>
+ * Copyright (C) 2015 - 2018 Linaro Ltd. <ard.biesheuvel@xxxxxxxxxx>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published
@@ -28,8 +28,10 @@ MODULE_ALIAS_CRYPTO("ghash");
#define GHASH_DIGEST_SIZE 16
struct ghash_key {
- u64 a;
- u64 b;
+ u64 h[2];
+ u64 h2[2];
+ u64 h3[2];
+ u64 h4[2];
};
struct ghash_desc_ctx {
@@ -117,26 +119,40 @@ static int ghash_final(struct shash_desc *desc, u8 *dst)
return 0;
}
+static void ghash_reflect(u64 h[], const be128 *k)
+{
+ u64 carry = be64_to_cpu(k->a) >> 63;
+
+ h[0] = (be64_to_cpu(k->b) << 1) | carry;
+ h[1] = (be64_to_cpu(k->a) << 1) | (be64_to_cpu(k->b) >> 63);
+
+ if (carry)
+ h[1] ^= 0xc200000000000000UL;
+}
+
static int ghash_setkey(struct crypto_shash *tfm,
const u8 *inkey, unsigned int keylen)
{
struct ghash_key *key = crypto_shash_ctx(tfm);
- u64 a, b;
+ be128 h, k;
if (keylen != GHASH_BLOCK_SIZE) {
crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
return -EINVAL;
}
- /* perform multiplication by 'x' in GF(2^128) */
- b = get_unaligned_be64(inkey);
- a = get_unaligned_be64(inkey + 8);
+ memcpy(&k, inkey, GHASH_BLOCK_SIZE);
+ ghash_reflect(key->h, &k);
+
+ h = k;
+ gf128mul_lle(&h, &k);
+ ghash_reflect(key->h2, &h);
- key->a = (a << 1) | (b >> 63);
- key->b = (b << 1) | (a >> 63);
+ gf128mul_lle(&h, &k);
+ ghash_reflect(key->h3, &h);
- if (b >> 63)
- key->b ^= 0xc200000000000000UL;
+ gf128mul_lle(&h, &k);
+ ghash_reflect(key->h4, &h);
return 0;
}
--
2.18.0
