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3759ee0572
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 4x 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.biesheuvel@linaro.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
243 lines
5.1 KiB
ArmAsm
243 lines
5.1 KiB
ArmAsm
/*
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* Accelerated GHASH implementation with NEON/ARMv8 vmull.p8/64 instructions.
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*
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* Copyright (C) 2015 - 2017 Linaro Ltd. <ard.biesheuvel@linaro.org>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 as published
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* by the Free Software Foundation.
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*/
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#include <linux/linkage.h>
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#include <asm/assembler.h>
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SHASH .req q0
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T1 .req q1
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XL .req q2
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XM .req q3
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XH .req q4
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IN1 .req q4
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SHASH_L .req d0
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SHASH_H .req d1
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T1_L .req d2
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T1_H .req d3
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XL_L .req d4
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XL_H .req d5
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XM_L .req d6
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XM_H .req d7
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XH_L .req d8
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t0l .req d10
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t0h .req d11
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t1l .req d12
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t1h .req d13
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t2l .req d14
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t2h .req d15
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t3l .req d16
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t3h .req d17
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t4l .req d18
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t4h .req d19
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t0q .req q5
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t1q .req q6
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t2q .req q7
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t3q .req q8
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t4q .req q9
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T2 .req q9
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s1l .req d20
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s1h .req d21
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s2l .req d22
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s2h .req d23
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s3l .req d24
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s3h .req d25
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s4l .req d26
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s4h .req d27
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MASK .req d28
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SHASH2_p8 .req d28
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k16 .req d29
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k32 .req d30
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k48 .req d31
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SHASH2_p64 .req d31
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.text
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.fpu crypto-neon-fp-armv8
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.macro __pmull_p64, rd, rn, rm, b1, b2, b3, b4
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vmull.p64 \rd, \rn, \rm
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.endm
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/*
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* This implementation of 64x64 -> 128 bit polynomial multiplication
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* using vmull.p8 instructions (8x8 -> 16) is taken from the paper
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* "Fast Software Polynomial Multiplication on ARM Processors Using
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* the NEON Engine" by Danilo Camara, Conrado Gouvea, Julio Lopez and
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* Ricardo Dahab (https://hal.inria.fr/hal-01506572)
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*
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* It has been slightly tweaked for in-order performance, and to allow
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* 'rq' to overlap with 'ad' or 'bd'.
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*/
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.macro __pmull_p8, rq, ad, bd, b1=t4l, b2=t3l, b3=t4l, b4=t3l
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vext.8 t0l, \ad, \ad, #1 @ A1
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.ifc \b1, t4l
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vext.8 t4l, \bd, \bd, #1 @ B1
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.endif
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vmull.p8 t0q, t0l, \bd @ F = A1*B
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vext.8 t1l, \ad, \ad, #2 @ A2
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vmull.p8 t4q, \ad, \b1 @ E = A*B1
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.ifc \b2, t3l
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vext.8 t3l, \bd, \bd, #2 @ B2
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.endif
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vmull.p8 t1q, t1l, \bd @ H = A2*B
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vext.8 t2l, \ad, \ad, #3 @ A3
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vmull.p8 t3q, \ad, \b2 @ G = A*B2
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veor t0q, t0q, t4q @ L = E + F
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.ifc \b3, t4l
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vext.8 t4l, \bd, \bd, #3 @ B3
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.endif
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vmull.p8 t2q, t2l, \bd @ J = A3*B
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veor t0l, t0l, t0h @ t0 = (L) (P0 + P1) << 8
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veor t1q, t1q, t3q @ M = G + H
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.ifc \b4, t3l
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vext.8 t3l, \bd, \bd, #4 @ B4
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.endif
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vmull.p8 t4q, \ad, \b3 @ I = A*B3
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veor t1l, t1l, t1h @ t1 = (M) (P2 + P3) << 16
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vmull.p8 t3q, \ad, \b4 @ K = A*B4
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vand t0h, t0h, k48
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vand t1h, t1h, k32
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veor t2q, t2q, t4q @ N = I + J
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veor t0l, t0l, t0h
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veor t1l, t1l, t1h
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veor t2l, t2l, t2h @ t2 = (N) (P4 + P5) << 24
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vand t2h, t2h, k16
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veor t3l, t3l, t3h @ t3 = (K) (P6 + P7) << 32
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vmov.i64 t3h, #0
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vext.8 t0q, t0q, t0q, #15
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veor t2l, t2l, t2h
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vext.8 t1q, t1q, t1q, #14
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vmull.p8 \rq, \ad, \bd @ D = A*B
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vext.8 t2q, t2q, t2q, #13
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vext.8 t3q, t3q, t3q, #12
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veor t0q, t0q, t1q
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veor t2q, t2q, t3q
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veor \rq, \rq, t0q
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veor \rq, \rq, t2q
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.endm
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//
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// PMULL (64x64->128) based reduction for CPUs that can do
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// it in a single instruction.
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//
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.macro __pmull_reduce_p64
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vmull.p64 T1, XL_L, MASK
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veor XH_L, XH_L, XM_H
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vext.8 T1, T1, T1, #8
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veor XL_H, XL_H, XM_L
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veor T1, T1, XL
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vmull.p64 XL, T1_H, MASK
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.endm
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//
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// Alternative reduction for CPUs that lack support for the
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// 64x64->128 PMULL instruction
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//
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.macro __pmull_reduce_p8
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veor XL_H, XL_H, XM_L
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veor XH_L, XH_L, XM_H
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vshl.i64 T1, XL, #57
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vshl.i64 T2, XL, #62
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veor T1, T1, T2
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vshl.i64 T2, XL, #63
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veor T1, T1, T2
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veor XL_H, XL_H, T1_L
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veor XH_L, XH_L, T1_H
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vshr.u64 T1, XL, #1
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veor XH, XH, XL
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veor XL, XL, T1
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vshr.u64 T1, T1, #6
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vshr.u64 XL, XL, #1
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.endm
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.macro ghash_update, pn
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vld1.64 {XL}, [r1]
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/* do the head block first, if supplied */
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ldr ip, [sp]
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teq ip, #0
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beq 0f
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vld1.64 {T1}, [ip]
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teq r0, #0
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b 1f
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0: vld1.64 {T1}, [r2]!
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subs r0, r0, #1
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1: /* multiply XL by SHASH in GF(2^128) */
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#ifndef CONFIG_CPU_BIG_ENDIAN
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vrev64.8 T1, T1
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#endif
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vext.8 IN1, T1, T1, #8
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veor T1_L, T1_L, XL_H
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veor XL, XL, IN1
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__pmull_\pn XH, XL_H, SHASH_H, s1h, s2h, s3h, s4h @ a1 * b1
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veor T1, T1, XL
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__pmull_\pn XL, XL_L, SHASH_L, s1l, s2l, s3l, s4l @ a0 * b0
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__pmull_\pn XM, T1_L, SHASH2_\pn @ (a1+a0)(b1+b0)
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veor T1, XL, XH
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veor XM, XM, T1
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__pmull_reduce_\pn
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veor T1, T1, XH
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veor XL, XL, T1
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bne 0b
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vst1.64 {XL}, [r1]
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bx lr
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.endm
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/*
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* void pmull_ghash_update(int blocks, u64 dg[], const char *src,
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* struct ghash_key const *k, const char *head)
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*/
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ENTRY(pmull_ghash_update_p64)
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vld1.64 {SHASH}, [r3]
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veor SHASH2_p64, SHASH_L, SHASH_H
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vmov.i8 MASK, #0xe1
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vshl.u64 MASK, MASK, #57
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ghash_update p64
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ENDPROC(pmull_ghash_update_p64)
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ENTRY(pmull_ghash_update_p8)
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vld1.64 {SHASH}, [r3]
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veor SHASH2_p8, SHASH_L, SHASH_H
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vext.8 s1l, SHASH_L, SHASH_L, #1
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vext.8 s2l, SHASH_L, SHASH_L, #2
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vext.8 s3l, SHASH_L, SHASH_L, #3
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vext.8 s4l, SHASH_L, SHASH_L, #4
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vext.8 s1h, SHASH_H, SHASH_H, #1
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vext.8 s2h, SHASH_H, SHASH_H, #2
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vext.8 s3h, SHASH_H, SHASH_H, #3
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vext.8 s4h, SHASH_H, SHASH_H, #4
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vmov.i64 k16, #0xffff
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vmov.i64 k32, #0xffffffff
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vmov.i64 k48, #0xffffffffffff
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ghash_update p8
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ENDPROC(pmull_ghash_update_p8)
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