arm64/crypto: improve performance of GHASH algorithm

This patches modifies the GHASH secure hash implementation to switch to a
faster, polynomial multiplication based reduction instead of one that uses
shifts and rotates.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Ard Biesheuvel 2014-06-16 11:02:16 +01:00 committed by Catalin Marinas
parent 6aa8b209f5
commit b913a6404c
2 changed files with 42 additions and 58 deletions

View File

@ -3,14 +3,6 @@
*
* Copyright (C) 2014 Linaro Ltd. <ard.biesheuvel@linaro.org>
*
* Based on arch/x86/crypto/ghash-pmullni-intel_asm.S
*
* Copyright (c) 2009 Intel Corp.
* Author: Huang Ying <ying.huang@intel.com>
* Vinodh Gopal
* Erdinc Ozturk
* Deniz Karakoyunlu
*
* 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
* by the Free Software Foundation.
@ -19,13 +11,15 @@
#include <linux/linkage.h>
#include <asm/assembler.h>
DATA .req v0
SHASH .req v1
IN1 .req v2
SHASH .req v0
SHASH2 .req v1
T1 .req v2
T2 .req v3
T3 .req v4
VZR .req v5
MASK .req v4
XL .req v5
XM .req v6
XH .req v7
IN1 .req v7
.text
.arch armv8-a+crypto
@ -35,61 +29,51 @@
* struct ghash_key const *k, const char *head)
*/
ENTRY(pmull_ghash_update)
ld1 {DATA.16b}, [x1]
ld1 {SHASH.16b}, [x3]
eor VZR.16b, VZR.16b, VZR.16b
ld1 {XL.16b}, [x1]
movi MASK.16b, #0xe1
ext SHASH2.16b, SHASH.16b, SHASH.16b, #8
shl MASK.2d, MASK.2d, #57
eor SHASH2.16b, SHASH2.16b, SHASH.16b
/* do the head block first, if supplied */
cbz x4, 0f
ld1 {IN1.2d}, [x4]
ld1 {T1.2d}, [x4]
b 1f
0: ld1 {IN1.2d}, [x2], #16
0: ld1 {T1.2d}, [x2], #16
sub w0, w0, #1
1: ext IN1.16b, IN1.16b, IN1.16b, #8
CPU_LE( rev64 IN1.16b, IN1.16b )
eor DATA.16b, DATA.16b, IN1.16b
/* multiply DATA by SHASH in GF(2^128) */
ext T2.16b, DATA.16b, DATA.16b, #8
ext T3.16b, SHASH.16b, SHASH.16b, #8
eor T2.16b, T2.16b, DATA.16b
eor T3.16b, T3.16b, SHASH.16b
1: /* multiply XL by SHASH in GF(2^128) */
CPU_LE( rev64 T1.16b, T1.16b )
pmull2 T1.1q, SHASH.2d, DATA.2d // a1 * b1
pmull DATA.1q, SHASH.1d, DATA.1d // a0 * b0
pmull T2.1q, T2.1d, T3.1d // (a1 + a0)(b1 + b0)
eor T2.16b, T2.16b, T1.16b // (a0 * b1) + (a1 * b0)
eor T2.16b, T2.16b, DATA.16b
ext T3.16b, VZR.16b, T2.16b, #8
ext T2.16b, T2.16b, VZR.16b, #8
eor DATA.16b, DATA.16b, T3.16b
eor T1.16b, T1.16b, T2.16b // <T1:DATA> is result of
// carry-less multiplication
/* first phase of the reduction */
shl T3.2d, DATA.2d, #1
eor T3.16b, T3.16b, DATA.16b
shl T3.2d, T3.2d, #5
eor T3.16b, T3.16b, DATA.16b
shl T3.2d, T3.2d, #57
ext T2.16b, VZR.16b, T3.16b, #8
ext T3.16b, T3.16b, VZR.16b, #8
eor DATA.16b, DATA.16b, T2.16b
eor T1.16b, T1.16b, T3.16b
/* second phase of the reduction */
ushr T2.2d, DATA.2d, #5
eor T2.16b, T2.16b, DATA.16b
ushr T2.2d, T2.2d, #1
eor T2.16b, T2.16b, DATA.16b
ushr T2.2d, T2.2d, #1
ext T2.16b, XL.16b, XL.16b, #8
ext IN1.16b, T1.16b, T1.16b, #8
eor T1.16b, T1.16b, T2.16b
eor DATA.16b, DATA.16b, T1.16b
eor XL.16b, XL.16b, IN1.16b
pmull2 XH.1q, SHASH.2d, XL.2d // a1 * b1
eor T1.16b, T1.16b, XL.16b
pmull XL.1q, SHASH.1d, XL.1d // a0 * b0
pmull XM.1q, SHASH2.1d, T1.1d // (a1 + a0)(b1 + b0)
ext T1.16b, XL.16b, XH.16b, #8
eor T2.16b, XL.16b, XH.16b
eor XM.16b, XM.16b, T1.16b
eor XM.16b, XM.16b, T2.16b
pmull T2.1q, XL.1d, MASK.1d
mov XH.d[0], XM.d[1]
mov XM.d[1], XL.d[0]
eor XL.16b, XM.16b, T2.16b
ext T2.16b, XL.16b, XL.16b, #8
pmull XL.1q, XL.1d, MASK.1d
eor T2.16b, T2.16b, XH.16b
eor XL.16b, XL.16b, T2.16b
cbnz w0, 0b
st1 {DATA.16b}, [x1]
st1 {XL.16b}, [x1]
ret
ENDPROC(pmull_ghash_update)

View File

@ -67,7 +67,7 @@ static int ghash_update(struct shash_desc *desc, const u8 *src,
blocks = len / GHASH_BLOCK_SIZE;
len %= GHASH_BLOCK_SIZE;
kernel_neon_begin_partial(6);
kernel_neon_begin_partial(8);
pmull_ghash_update(blocks, ctx->digest, src, key,
partial ? ctx->buf : NULL);
kernel_neon_end();
@ -89,7 +89,7 @@ static int ghash_final(struct shash_desc *desc, u8 *dst)
memset(ctx->buf + partial, 0, GHASH_BLOCK_SIZE - partial);
kernel_neon_begin_partial(6);
kernel_neon_begin_partial(8);
pmull_ghash_update(1, ctx->digest, ctx->buf, key, NULL);
kernel_neon_end();
}