1/*
2 * Accelerated GHASH implementation with Intel PCLMULQDQ-NI
3 * instructions. This file contains accelerated part of ghash
4 * implementation. More information about PCLMULQDQ can be found at:
5 *
6 * http://software.intel.com/en-us/articles/carry-less-multiplication-and-its-usage-for-computing-the-gcm-mode/
7 *
8 * Copyright (c) 2009 Intel Corp.
9 *   Author: Huang Ying <ying.huang@intel.com>
10 *	     Vinodh Gopal
11 *	     Erdinc Ozturk
12 *	     Deniz Karakoyunlu
13 *
14 * This program is free software; you can redistribute it and/or modify it
15 * under the terms of the GNU General Public License version 2 as published
16 * by the Free Software Foundation.
17 */
18
19#include <linux/linkage.h>
20#include <asm/inst.h>
21
22.data
23
24.align 16
25.Lbswap_mask:
26	.octa 0x000102030405060708090a0b0c0d0e0f
27.Lpoly:
28	.octa 0xc2000000000000000000000000000001
29.Ltwo_one:
30	.octa 0x00000001000000000000000000000001
31
32#define DATA	%xmm0
33#define SHASH	%xmm1
34#define T1	%xmm2
35#define T2	%xmm3
36#define T3	%xmm4
37#define BSWAP	%xmm5
38#define IN1	%xmm6
39
40.text
41
42/*
43 * __clmul_gf128mul_ble:	internal ABI
44 * input:
45 *	DATA:			operand1
46 *	SHASH:			operand2, hash_key << 1 mod poly
47 * output:
48 *	DATA:			operand1 * operand2 mod poly
49 * changed:
50 *	T1
51 *	T2
52 *	T3
53 */
54__clmul_gf128mul_ble:
55	movaps DATA, T1
56	pshufd $0b01001110, DATA, T2
57	pshufd $0b01001110, SHASH, T3
58	pxor DATA, T2
59	pxor SHASH, T3
60
61	PCLMULQDQ 0x00 SHASH DATA	# DATA = a0 * b0
62	PCLMULQDQ 0x11 SHASH T1		# T1 = a1 * b1
63	PCLMULQDQ 0x00 T3 T2		# T2 = (a1 + a0) * (b1 + b0)
64	pxor DATA, T2
65	pxor T1, T2			# T2 = a0 * b1 + a1 * b0
66
67	movaps T2, T3
68	pslldq $8, T3
69	psrldq $8, T2
70	pxor T3, DATA
71	pxor T2, T1			# <T1:DATA> is result of
72					# carry-less multiplication
73
74	# first phase of the reduction
75	movaps DATA, T3
76	psllq $1, T3
77	pxor DATA, T3
78	psllq $5, T3
79	pxor DATA, T3
80	psllq $57, T3
81	movaps T3, T2
82	pslldq $8, T2
83	psrldq $8, T3
84	pxor T2, DATA
85	pxor T3, T1
86
87	# second phase of the reduction
88	movaps DATA, T2
89	psrlq $5, T2
90	pxor DATA, T2
91	psrlq $1, T2
92	pxor DATA, T2
93	psrlq $1, T2
94	pxor T2, T1
95	pxor T1, DATA
96	ret
97
98/* void clmul_ghash_mul(char *dst, const be128 *shash) */
99ENTRY(clmul_ghash_mul)
100	movups (%rdi), DATA
101	movups (%rsi), SHASH
102	movaps .Lbswap_mask, BSWAP
103	PSHUFB_XMM BSWAP DATA
104	call __clmul_gf128mul_ble
105	PSHUFB_XMM BSWAP DATA
106	movups DATA, (%rdi)
107	ret
108
109/*
110 * void clmul_ghash_update(char *dst, const char *src, unsigned int srclen,
111 *			   const be128 *shash);
112 */
113ENTRY(clmul_ghash_update)
114	cmp $16, %rdx
115	jb .Lupdate_just_ret	# check length
116	movaps .Lbswap_mask, BSWAP
117	movups (%rdi), DATA
118	movups (%rcx), SHASH
119	PSHUFB_XMM BSWAP DATA
120.align 4
121.Lupdate_loop:
122	movups (%rsi), IN1
123	PSHUFB_XMM BSWAP IN1
124	pxor IN1, DATA
125	call __clmul_gf128mul_ble
126	sub $16, %rdx
127	add $16, %rsi
128	cmp $16, %rdx
129	jge .Lupdate_loop
130	PSHUFB_XMM BSWAP DATA
131	movups DATA, (%rdi)
132.Lupdate_just_ret:
133	ret
134
135/*
136 * void clmul_ghash_setkey(be128 *shash, const u8 *key);
137 *
138 * Calculate hash_key << 1 mod poly
139 */
140ENTRY(clmul_ghash_setkey)
141	movaps .Lbswap_mask, BSWAP
142	movups (%rsi), %xmm0
143	PSHUFB_XMM BSWAP %xmm0
144	movaps %xmm0, %xmm1
145	psllq $1, %xmm0
146	psrlq $63, %xmm1
147	movaps %xmm1, %xmm2
148	pslldq $8, %xmm1
149	psrldq $8, %xmm2
150	por %xmm1, %xmm0
151	# reduction
152	pshufd $0b00100100, %xmm2, %xmm1
153	pcmpeqd .Ltwo_one, %xmm1
154	pand .Lpoly, %xmm1
155	pxor %xmm1, %xmm0
156	movups %xmm0, (%rdi)
157	ret
158