1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * Accelerated GHASH implementation with Intel PCLMULQDQ-NI
4 * instructions. This file contains accelerated part of ghash
5 * implementation. More information about PCLMULQDQ can be found at:
6 *
7 * https://www.intel.com/content/dam/develop/external/us/en/documents/clmul-wp-rev-2-02-2014-04-20.pdf
8 *
9 * Copyright (c) 2009 Intel Corp.
10 * Author: Huang Ying <ying.huang@intel.com>
11 * Vinodh Gopal
12 * Erdinc Ozturk
13 * Deniz Karakoyunlu
14 */
15
16#include <linux/linkage.h>
17#include <asm/frame.h>
18
19.section .rodata.cst16.bswap_mask, "aM", @progbits, 16
20.align 16
21.Lbswap_mask:
22 .octa 0x000102030405060708090a0b0c0d0e0f
23
24#define DATA %xmm0
25#define SHASH %xmm1
26#define T1 %xmm2
27#define T2 %xmm3
28#define T3 %xmm4
29#define BSWAP %xmm5
30#define IN1 %xmm6
31
32.text
33
34/*
35 * __clmul_gf128mul_ble: internal ABI
36 * input:
37 * DATA: operand1
38 * SHASH: operand2, hash_key << 1 mod poly
39 * output:
40 * DATA: operand1 * operand2 mod poly
41 * changed:
42 * T1
43 * T2
44 * T3
45 */
46SYM_FUNC_START_LOCAL(__clmul_gf128mul_ble)
47 movaps DATA, T1
48 pshufd $0b01001110, DATA, T2
49 pshufd $0b01001110, SHASH, T3
50 pxor DATA, T2
51 pxor SHASH, T3
52
53 pclmulqdq $0x00, SHASH, DATA # DATA = a0 * b0
54 pclmulqdq $0x11, SHASH, T1 # T1 = a1 * b1
55 pclmulqdq $0x00, T3, T2 # T2 = (a1 + a0) * (b1 + b0)
56 pxor DATA, T2
57 pxor T1, T2 # T2 = a0 * b1 + a1 * b0
58
59 movaps T2, T3
60 pslldq $8, T3
61 psrldq $8, T2
62 pxor T3, DATA
63 pxor T2, T1 # <T1:DATA> is result of
64 # carry-less multiplication
65
66 # first phase of the reduction
67 movaps DATA, T3
68 psllq $1, T3
69 pxor DATA, T3
70 psllq $5, T3
71 pxor DATA, T3
72 psllq $57, T3
73 movaps T3, T2
74 pslldq $8, T2
75 psrldq $8, T3
76 pxor T2, DATA
77 pxor T3, T1
78
79 # second phase of the reduction
80 movaps DATA, T2
81 psrlq $5, T2
82 pxor DATA, T2
83 psrlq $1, T2
84 pxor DATA, T2
85 psrlq $1, T2
86 pxor T2, T1
87 pxor T1, DATA
88 RET
89SYM_FUNC_END(__clmul_gf128mul_ble)
90
91/* void clmul_ghash_mul(char *dst, const le128 *shash) */
92SYM_FUNC_START(clmul_ghash_mul)
93 FRAME_BEGIN
94 movups (%rdi), DATA
95 movups (%rsi), SHASH
96 movaps .Lbswap_mask(%rip), BSWAP
97 pshufb BSWAP, DATA
98 call __clmul_gf128mul_ble
99 pshufb BSWAP, DATA
100 movups DATA, (%rdi)
101 FRAME_END
102 RET
103SYM_FUNC_END(clmul_ghash_mul)
104
105/*
106 * int clmul_ghash_update(char *dst, const char *src, unsigned int srclen,
107 * const le128 *shash);
108 */
109SYM_FUNC_START(clmul_ghash_update)
110 FRAME_BEGIN
111 cmp $16, %rdx
112 jb .Lupdate_just_ret # check length
113 movaps .Lbswap_mask(%rip), BSWAP
114 movups (%rdi), DATA
115 movups (%rcx), SHASH
116 pshufb BSWAP, DATA
117.align 4
118.Lupdate_loop:
119 movups (%rsi), IN1
120 pshufb BSWAP, IN1
121 pxor IN1, DATA
122 call __clmul_gf128mul_ble
123 sub $16, %rdx
124 add $16, %rsi
125 cmp $16, %rdx
126 jge .Lupdate_loop
127 pshufb BSWAP, DATA
128 movups DATA, (%rdi)
129.Lupdate_just_ret:
130 mov %rdx, %rax
131 FRAME_END
132 RET
133SYM_FUNC_END(clmul_ghash_update)
134

source code of linux/arch/x86/crypto/ghash-clmulni-intel_asm.S