Implement a NEON fallback for systems that do support NEON but have
no support for the optional 64x64->128 polynomial multiplication
instruction that is part of the ARMv8 Crypto Extensions. It is based
on the paper "Fast Software Polynomial Multiplication on ARM Processors
Using the NEON Engine" by Danilo Camara, Conrado Gouvea, Julio Lopez and
Ricardo Dahab (https://hal.inria.fr/hal-01506572)
On a 32-bit guest executing under KVM on a Cortex-A57, the new code is
not only >3x faster than the generic table based GHASH driver, it is also
time invariant. (Note that the existing vmull.p64 code is 16x faster on
this core).
Signed-off-by: Ard Biesheuvel <ard.biesheu...@linaro.org>
---
Raw numbers for a 2 GHz AMD Seattle (A57 r1p2) after the patch.
arch/arm/crypto/Kconfig | 5 +-
arch/arm/crypto/ghash-ce-core.S | 110 +++++++++++++++++---
arch/arm/crypto/ghash-ce-glue.c | 24 ++++-
3 files changed, 119 insertions(+), 20 deletions(-)
diff --git a/arch/arm/crypto/Kconfig b/arch/arm/crypto/Kconfig
index d8f3336bfc88..0b960ed124ae 100644
--- a/arch/arm/crypto/Kconfig
+++ b/arch/arm/crypto/Kconfig
@@ -106,14 +106,15 @@ config CRYPTO_AES_ARM_CE
ARMv8 Crypto Extensions
config CRYPTO_GHASH_ARM_CE
- tristate "PMULL-accelerated GHASH using ARMv8 Crypto Extensions"
+ tristate "PMULL-accelerated GHASH using NEON/ARMv8 Crypto Extensions"
depends on KERNEL_MODE_NEON
select CRYPTO_HASH
select CRYPTO_CRYPTD
help
Use an implementation of GHASH (used by the GCM AEAD chaining mode)
that uses the 64x64 to 128 bit polynomial multiplication (vmull.p64)
- that is part of the ARMv8 Crypto Extensions
+ that is part of the ARMv8 Crypto Extensions, or a slower variant that
+ uses the vmull.p8 instruction that is part of the basic NEON ISA.
config CRYPTO_CRCT10DIF_ARM_CE
tristate "CRCT10DIF digest algorithm using PMULL instructions"
diff --git a/arch/arm/crypto/ghash-ce-core.S b/arch/arm/crypto/ghash-ce-core.S
index f6ab8bcc9efe..a017a9213f7e 100644
--- a/arch/arm/crypto/ghash-ce-core.S
+++ b/arch/arm/crypto/ghash-ce-core.S
@@ -1,7 +1,7 @@
/*
- * Accelerated GHASH implementation with ARMv8 vmull.p64 instructions.
+ * Accelerated GHASH implementation with NEON/ARMv8 vmull.p8/64 instructions.
*
- * Copyright (C) 2015 Linaro Ltd. <ard.biesheu...@linaro.org>
+ * Copyright (C) 2015 - 2017 Linaro Ltd. <ard.biesheu...@linaro.org>
*
* 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
@@ -20,26 +20,90 @@
XM .req q6
XH .req q7
IN1 .req q7
+ T3 .req q8
SHASH_L .req d0
SHASH_H .req d1
SHASH2_L .req d2
T1_L .req d4
+ T2_L .req d6
MASK_L .req d8
XL_L .req d10
XL_H .req d11
XM_L .req d12
XM_H .req d13
XH_L .req d14
+ T3_L .req d16
+
+ k16 .req d21
+ k32 .req d22
+ k48 .req d23
+
+ t0l .req d24
+ t0h .req d25
+ t1l .req d26
+ t1h .req d27
+ t2l .req d28
+ t2h .req d29
+ t3l .req d30
+ t3h .req d31
+
+ t0q .req q12
+ t1q .req q13
+ t2q .req q14
+ t3q .req q15
.text
.fpu crypto-neon-fp-armv8
/*
- * void pmull_ghash_update(int blocks, u64 dg[], const char *src,
- * struct ghash_key const *k, const char *head)
+ * This implementation of 64x64 -> 128 bit polynomial multiplication
+ * using vmull.p8 instructions (8x8 -> 16) is taken from the paper
+ * "Fast Software Polynomial Multiplication on ARM Processors Using
+ * the NEON Engine" by Danilo Camara, Conrado Gouvea, Julio Lopez and
+ * Ricardo Dahab (https://hal.inria.fr/hal-01506572)
*/
-ENTRY(pmull_ghash_update)
+ .macro vmull_p64, rq, ad, bd
+ vext.8 t0l, \ad, \ad, #1 @ A1
+ vmull.p8 t0q, t0l, \bd @ F = A1*B
+ vext.8 \rq\()_L, \bd, \bd, #1 @ B1
+ vmull.p8 \rq, \ad, \rq\()_L @ E = A*B1
+ vext.8 t1l, \ad, \ad, #2 @ A2
+ vmull.p8 t1q, t1l, \bd @ H = A2*B
+ vext.8 t3l, \bd, \bd, #2 @ B2
+ vmull.p8 t3q, \ad, t3l @ G = A*B2
+ vext.8 t2l, \ad, \ad, #3 @ A3
+ vmull.p8 t2q, t2l, \bd @ J = A3*B
+ veor t0q, t0q, \rq @ L = E + F
+ vext.8 \rq\()_L, \bd, \bd, #3 @ B3
+ vmull.p8 \rq, \ad, \rq\()_L @ I = A*B3
+ veor t1q, t1q, t3q @ M = G + H
+ vext.8 t3l, \bd, \bd, #4 @ B4
+ vmull.p8 t3q, \ad, t3l @ K = A*B4
+ veor t0l, t0l, t0h @ t0 = (L) (P0 + P1) << 8
+ vand t0h, t0h, k48
+ veor t1l, t1l, t1h @ t1 = (M) (P2 + P3) << 16
+ vand t1h, t1h, k32
+ veor t2q, t2q, \rq @ N = I + J
+ veor t0l, t0l, t0h
+ veor t1l, t1l, t1h
+ veor t2l, t2l, t2h @ t2 = (N) (P4 + P5) << 24
+ vand t2h, t2h, k16
+ veor t3l, t3l, t3h @ t3 = (K) (P6 + P7) << 32
+ vmov.i64 t3h, #0
+ vext.8 t0q, t0q, t0q, #15
+ veor t2l, t2l, t2h
+ vext.8 t1q, t1q, t1q, #14
+ vmull.p8 \rq, \ad, \bd @ D = A*B
+ vext.8 t2q, t2q, t2q, #13
+ vext.8 t3q, t3q, t3q, #12
+ veor t0q, t0q, t1q
+ veor t2q, t2q, t3q
+ veor \rq, \rq, t0q
+ veor \rq, \rq, t2q
+ .endm
+
+ .macro ghash_update, vp64
vld1.64 {SHASH}, [r3]
vld1.64 {XL}, [r1]
vmov.i8 MASK, #0xe1
@@ -67,28 +131,44 @@ ENTRY(pmull_ghash_update)
veor T1, T1, T2
veor XL, XL, IN1
- vmull.p64 XH, SHASH_H, XL_H @ a1 * b1
+ \vp64 XH, SHASH_H, XL_H @ a1 * b1
veor T1, T1, XL
- vmull.p64 XL, SHASH_L, XL_L @ a0 * b0
- vmull.p64 XM, SHASH2_L, T1_L @ (a1 + a0)(b1 + b0)
+ \vp64 T3, SHASH_L, XL_L @ a0 * b0
+ \vp64 XM, SHASH2_L, T1_L @ (a1 + a0)(b1 + b0)
- vext.8 T1, XL, XH, #8
- veor T2, XL, XH
+ vext.8 T1, T3, XH, #8
+ veor T2, T3, XH
veor XM, XM, T1
veor XM, XM, T2
- vmull.p64 T2, XL_L, MASK_L
+ \vp64 T2, T3_L, MASK_L
vmov XH_L, XM_H
- vmov XM_H, XL_L
+ vmov XM_H, T3_L
veor XL, XM, T2
vext.8 T2, XL, XL, #8
- vmull.p64 XL, XL_L, MASK_L
+ \vp64 T1, XL_L, MASK_L
veor T2, T2, XH
- veor XL, XL, T2
+ veor XL, T1, T2
bne 0b
vst1.64 {XL}, [r1]
bx lr
-ENDPROC(pmull_ghash_update)
+ .endm
+
+ /*
+ * void pmull_ghash_update(int blocks, u64 dg[], const char *src,
+ * struct ghash_key const *k, const char *head)
+ */
+ENTRY(pmull_ghash_update_p64)
+ ghash_update vmull.p64
+ENDPROC(pmull_ghash_update_p64)
+
+ENTRY(pmull_ghash_update_p8)
+ vmov.i64 k16, #0xffff
+ vmov.i64 k32, #0xffffffff
+ vmov.i64 k48, #0xffffffffffff
+
+ ghash_update vmull_p64
+ENDPROC(pmull_ghash_update_p8)
diff --git a/arch/arm/crypto/ghash-ce-glue.c b/arch/arm/crypto/ghash-ce-glue.c
index 6bac8bea9f1e..d9bb52cae2ac 100644
--- a/arch/arm/crypto/ghash-ce-glue.c
+++ b/arch/arm/crypto/ghash-ce-glue.c
@@ -22,6 +22,7 @@
MODULE_DESCRIPTION("GHASH secure hash using ARMv8 Crypto Extensions");
MODULE_AUTHOR("Ard Biesheuvel <ard.biesheu...@linaro.org>");
MODULE_LICENSE("GPL v2");
+MODULE_ALIAS_CRYPTO("ghash");
#define GHASH_BLOCK_SIZE 16
#define GHASH_DIGEST_SIZE 16
@@ -41,8 +42,17 @@ struct ghash_async_ctx {
struct cryptd_ahash *cryptd_tfm;
};
-asmlinkage void pmull_ghash_update(int blocks, u64 dg[], const char *src,
- struct ghash_key const *k, const char *head);
+asmlinkage void pmull_ghash_update_p64(int blocks, u64 dg[], const char *src,
+ struct ghash_key const *k,
+ const char *head);
+
+asmlinkage void pmull_ghash_update_p8(int blocks, u64 dg[], const char *src,
+ struct ghash_key const *k,
+ const char *head);
+
+static void (*pmull_ghash_update)(int blocks, u64 dg[], const char *src,
+ struct ghash_key const *k,
+ const char *head);
static int ghash_init(struct shash_desc *desc)
{
@@ -312,6 +322,14 @@ static int __init ghash_ce_mod_init(void)
{
int err;
+ if (!(elf_hwcap & HWCAP_NEON))
+ return -ENODEV;
+
+ if (elf_hwcap2 & HWCAP2_PMULL)
+ pmull_ghash_update = pmull_ghash_update_p64;
+ else
+ pmull_ghash_update = pmull_ghash_update_p8;
+
err = crypto_register_shash(&ghash_alg);
if (err)
return err;
@@ -332,5 +350,5 @@ static void __exit ghash_ce_mod_exit(void)
crypto_unregister_shash(&ghash_alg);
}
-module_cpu_feature_match(PMULL, ghash_ce_mod_init);
+module_init(ghash_ce_mod_init);
module_exit(ghash_ce_mod_exit);
--
2.9.3
Generic
-------
0 ( 1 x 16 = 16 bytes): 2935029 opers/sec, 46960464 bytes/sec
1 ( 4 x 16 = 64 bytes): 755992 opers/sec, 48383488 bytes/sec
2 ( 1 x 64 = 64 bytes): 885186 opers/sec, 56651904 bytes/sec
3 ( 16 x 16 = 256 bytes): 194153 opers/sec, 49703168 bytes/sec
4 ( 4 x 64 = 256 bytes): 224917 opers/sec, 57578752 bytes/sec
5 ( 1 x 256 = 256 bytes): 241253 opers/sec, 61760768 bytes/sec
6 ( 64 x 16 = 1024 bytes): 49550 opers/sec, 50739200 bytes/sec
7 ( 4 x 256 = 1024 bytes): 60396 opers/sec, 61845504 bytes/sec
8 ( 1 x 1024 = 1024 bytes): 61320 opers/sec, 62791680 bytes/sec
9 (128 x 16 = 2048 bytes): 24809 opers/sec, 50808832 bytes/sec
10 ( 8 x 256 = 2048 bytes): 30236 opers/sec, 61923328 bytes/sec
11 ( 2 x 1024 = 2048 bytes): 30654 opers/sec, 62779392 bytes/sec
12 ( 1 x 2048 = 2048 bytes): 30791 opers/sec, 63059968 bytes/sec
13 (256 x 16 = 4096 bytes): 12402 opers/sec, 50798592 bytes/sec
14 ( 16 x 256 = 4096 bytes): 15128 opers/sec, 61964288 bytes/sec
15 ( 4 x 1024 = 4096 bytes): 15334 opers/sec, 62808064 bytes/sec
16 ( 1 x 4096 = 4096 bytes): 15400 opers/sec, 63078400 bytes/sec
17 (512 x 16 = 8192 bytes): 6199 opers/sec, 50782208 bytes/sec
18 ( 32 x 256 = 8192 bytes): 7566 opers/sec, 61980672 bytes/sec
19 ( 8 x 1024 = 8192 bytes): 7672 opers/sec, 62849024 bytes/sec
20 ( 2 x 4096 = 8192 bytes): 7710 opers/sec, 63160320 bytes/sec
21 ( 1 x 8192 = 8192 bytes): 7088 opers/sec, 58064896 bytes/sec
vmull.p8
--------
0 ( 1 x 16 = 16 bytes): 3677447 opers/sec, 58839152 bytes/sec
1 ( 4 x 16 = 64 bytes): 998104 opers/sec, 63878656 bytes/sec
2 ( 1 x 64 = 64 bytes): 1968136 opers/sec, 125960704 bytes/sec
3 ( 16 x 16 = 256 bytes): 263350 opers/sec, 67417600 bytes/sec
4 ( 4 x 64 = 256 bytes): 500690 opers/sec, 128176640 bytes/sec
5 ( 1 x 256 = 256 bytes): 673571 opers/sec, 172434176 bytes/sec
6 ( 64 x 16 = 1024 bytes): 65698 opers/sec, 67274752 bytes/sec
7 ( 4 x 256 = 1024 bytes): 171073 opers/sec, 175178752 bytes/sec
8 ( 1 x 1024 = 1024 bytes): 185430 opers/sec, 189880320 bytes/sec
9 (128 x 16 = 2048 bytes): 33761 opers/sec, 69142528 bytes/sec
10 ( 8 x 256 = 2048 bytes): 86010 opers/sec, 176148480 bytes/sec
11 ( 2 x 1024 = 2048 bytes): 92724 opers/sec, 189898752 bytes/sec
12 ( 1 x 2048 = 2048 bytes): 95416 opers/sec, 195411968 bytes/sec
13 (256 x 16 = 4096 bytes): 16887 opers/sec, 69169152 bytes/sec
14 ( 16 x 256 = 4096 bytes): 43145 opers/sec, 176721920 bytes/sec
15 ( 4 x 1024 = 4096 bytes): 46462 opers/sec, 190308352 bytes/sec
16 ( 1 x 4096 = 4096 bytes): 47651 opers/sec, 195178496 bytes/sec
17 (512 x 16 = 8192 bytes): 8452 opers/sec, 69238784 bytes/sec
18 ( 32 x 256 = 8192 bytes): 21581 opers/sec, 176791552 bytes/sec
19 ( 8 x 1024 = 8192 bytes): 23264 opers/sec, 190578688 bytes/sec
20 ( 2 x 4096 = 8192 bytes): 23896 opers/sec, 195756032 bytes/sec
21 ( 1 x 8192 = 8192 bytes): 22950 opers/sec, 188006400 bytes/sec
vmull.p64
---------
0 ( 1 x 16 = 16 bytes): 4896330 opers/sec, 78341280 bytes/sec
1 ( 4 x 16 = 64 bytes): 1340210 opers/sec, 85773440 bytes/sec
2 ( 1 x 64 = 64 bytes): 3646331 opers/sec, 233365184 bytes/sec
3 ( 16 x 16 = 256 bytes): 364655 opers/sec, 93351680 bytes/sec
4 ( 4 x 64 = 256 bytes): 1054796 opers/sec, 270027776 bytes/sec
5 ( 1 x 256 = 256 bytes): 2196935 opers/sec, 562415360 bytes/sec
6 ( 64 x 16 = 1024 bytes): 93104 opers/sec, 95338496 bytes/sec
7 ( 4 x 256 = 1024 bytes): 575183 opers/sec, 588987392 bytes/sec
8 ( 1 x 1024 = 1024 bytes): 801655 opers/sec, 820894720 bytes/sec
9 (128 x 16 = 2048 bytes): 46715 opers/sec, 95672320 bytes/sec
10 ( 8 x 256 = 2048 bytes): 293469 opers/sec, 601024512 bytes/sec
11 ( 2 x 1024 = 2048 bytes): 401675 opers/sec, 822630400 bytes/sec
12 ( 1 x 2048 = 2048 bytes): 434725 opers/sec, 890316800 bytes/sec
13 (256 x 16 = 4096 bytes): 23353 opers/sec, 95653888 bytes/sec
14 ( 16 x 256 = 4096 bytes): 148155 opers/sec, 606842880 bytes/sec
15 ( 4 x 1024 = 4096 bytes): 203664 opers/sec, 834207744 bytes/sec
16 ( 1 x 4096 = 4096 bytes): 226047 opers/sec, 925888512 bytes/sec
17 (512 x 16 = 8192 bytes): 11695 opers/sec, 95805440 bytes/sec
18 ( 32 x 256 = 8192 bytes): 74366 opers/sec, 609206272 bytes/sec
19 ( 8 x 1024 = 8192 bytes): 102665 opers/sec, 841031680 bytes/sec
20 ( 2 x 4096 = 8192 bytes): 113337 opers/sec, 928456704 bytes/sec
21 ( 1 x 8192 = 8192 bytes): 113695 opers/sec, 931389440 bytes/sec
