1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Poly1305 authenticator algorithm, RFC7539, SIMD glue code
4 *
5 * Copyright (C) 2015 Martin Willi
6 */
7
8 #include <crypto/algapi.h>
9 #include <crypto/internal/hash.h>
10 #include <crypto/internal/simd.h>
11 #include <crypto/poly1305.h>
12 #include <linux/crypto.h>
13 #include <linux/kernel.h>
14 #include <linux/module.h>
15 #include <asm/simd.h>
16
17 struct poly1305_simd_desc_ctx {
18 struct poly1305_desc_ctx base;
19 /* derived key u set? */
20 bool uset;
21 #ifdef CONFIG_AS_AVX2
22 /* derived keys r^3, r^4 set? */
23 bool wset;
24 #endif
25 /* derived Poly1305 key r^2 */
26 u32 u[5];
27 /* ... silently appended r^3 and r^4 when using AVX2 */
28 };
29
30 asmlinkage void poly1305_block_sse2(u32 *h, const u8 *src,
31 const u32 *r, unsigned int blocks);
32 asmlinkage void poly1305_2block_sse2(u32 *h, const u8 *src, const u32 *r,
33 unsigned int blocks, const u32 *u);
34 #ifdef CONFIG_AS_AVX2
35 asmlinkage void poly1305_4block_avx2(u32 *h, const u8 *src, const u32 *r,
36 unsigned int blocks, const u32 *u);
37 static bool poly1305_use_avx2;
38 #endif
39
poly1305_simd_init(struct shash_desc * desc)40 static int poly1305_simd_init(struct shash_desc *desc)
41 {
42 struct poly1305_simd_desc_ctx *sctx = shash_desc_ctx(desc);
43
44 sctx->uset = false;
45 #ifdef CONFIG_AS_AVX2
46 sctx->wset = false;
47 #endif
48
49 return crypto_poly1305_init(desc);
50 }
51
poly1305_simd_mult(u32 * a,const u32 * b)52 static void poly1305_simd_mult(u32 *a, const u32 *b)
53 {
54 u8 m[POLY1305_BLOCK_SIZE];
55
56 memset(m, 0, sizeof(m));
57 /* The poly1305 block function adds a hi-bit to the accumulator which
58 * we don't need for key multiplication; compensate for it. */
59 a[4] -= 1 << 24;
60 poly1305_block_sse2(a, m, b, 1);
61 }
62
poly1305_simd_blocks(struct poly1305_desc_ctx * dctx,const u8 * src,unsigned int srclen)63 static unsigned int poly1305_simd_blocks(struct poly1305_desc_ctx *dctx,
64 const u8 *src, unsigned int srclen)
65 {
66 struct poly1305_simd_desc_ctx *sctx;
67 unsigned int blocks, datalen;
68
69 BUILD_BUG_ON(offsetof(struct poly1305_simd_desc_ctx, base));
70 sctx = container_of(dctx, struct poly1305_simd_desc_ctx, base);
71
72 if (unlikely(!dctx->sset)) {
73 datalen = crypto_poly1305_setdesckey(dctx, src, srclen);
74 src += srclen - datalen;
75 srclen = datalen;
76 }
77
78 #ifdef CONFIG_AS_AVX2
79 if (poly1305_use_avx2 && srclen >= POLY1305_BLOCK_SIZE * 4) {
80 if (unlikely(!sctx->wset)) {
81 if (!sctx->uset) {
82 memcpy(sctx->u, dctx->r.r, sizeof(sctx->u));
83 poly1305_simd_mult(sctx->u, dctx->r.r);
84 sctx->uset = true;
85 }
86 memcpy(sctx->u + 5, sctx->u, sizeof(sctx->u));
87 poly1305_simd_mult(sctx->u + 5, dctx->r.r);
88 memcpy(sctx->u + 10, sctx->u + 5, sizeof(sctx->u));
89 poly1305_simd_mult(sctx->u + 10, dctx->r.r);
90 sctx->wset = true;
91 }
92 blocks = srclen / (POLY1305_BLOCK_SIZE * 4);
93 poly1305_4block_avx2(dctx->h.h, src, dctx->r.r, blocks,
94 sctx->u);
95 src += POLY1305_BLOCK_SIZE * 4 * blocks;
96 srclen -= POLY1305_BLOCK_SIZE * 4 * blocks;
97 }
98 #endif
99 if (likely(srclen >= POLY1305_BLOCK_SIZE * 2)) {
100 if (unlikely(!sctx->uset)) {
101 memcpy(sctx->u, dctx->r.r, sizeof(sctx->u));
102 poly1305_simd_mult(sctx->u, dctx->r.r);
103 sctx->uset = true;
104 }
105 blocks = srclen / (POLY1305_BLOCK_SIZE * 2);
106 poly1305_2block_sse2(dctx->h.h, src, dctx->r.r, blocks,
107 sctx->u);
108 src += POLY1305_BLOCK_SIZE * 2 * blocks;
109 srclen -= POLY1305_BLOCK_SIZE * 2 * blocks;
110 }
111 if (srclen >= POLY1305_BLOCK_SIZE) {
112 poly1305_block_sse2(dctx->h.h, src, dctx->r.r, 1);
113 srclen -= POLY1305_BLOCK_SIZE;
114 }
115 return srclen;
116 }
117
poly1305_simd_update(struct shash_desc * desc,const u8 * src,unsigned int srclen)118 static int poly1305_simd_update(struct shash_desc *desc,
119 const u8 *src, unsigned int srclen)
120 {
121 struct poly1305_desc_ctx *dctx = shash_desc_ctx(desc);
122 unsigned int bytes;
123
124 /* kernel_fpu_begin/end is costly, use fallback for small updates */
125 if (srclen <= 288 || !crypto_simd_usable())
126 return crypto_poly1305_update(desc, src, srclen);
127
128 kernel_fpu_begin();
129
130 if (unlikely(dctx->buflen)) {
131 bytes = min(srclen, POLY1305_BLOCK_SIZE - dctx->buflen);
132 memcpy(dctx->buf + dctx->buflen, src, bytes);
133 src += bytes;
134 srclen -= bytes;
135 dctx->buflen += bytes;
136
137 if (dctx->buflen == POLY1305_BLOCK_SIZE) {
138 poly1305_simd_blocks(dctx, dctx->buf,
139 POLY1305_BLOCK_SIZE);
140 dctx->buflen = 0;
141 }
142 }
143
144 if (likely(srclen >= POLY1305_BLOCK_SIZE)) {
145 bytes = poly1305_simd_blocks(dctx, src, srclen);
146 src += srclen - bytes;
147 srclen = bytes;
148 }
149
150 kernel_fpu_end();
151
152 if (unlikely(srclen)) {
153 dctx->buflen = srclen;
154 memcpy(dctx->buf, src, srclen);
155 }
156
157 return 0;
158 }
159
160 static struct shash_alg alg = {
161 .digestsize = POLY1305_DIGEST_SIZE,
162 .init = poly1305_simd_init,
163 .update = poly1305_simd_update,
164 .final = crypto_poly1305_final,
165 .descsize = sizeof(struct poly1305_simd_desc_ctx),
166 .base = {
167 .cra_name = "poly1305",
168 .cra_driver_name = "poly1305-simd",
169 .cra_priority = 300,
170 .cra_blocksize = POLY1305_BLOCK_SIZE,
171 .cra_module = THIS_MODULE,
172 },
173 };
174
poly1305_simd_mod_init(void)175 static int __init poly1305_simd_mod_init(void)
176 {
177 if (!boot_cpu_has(X86_FEATURE_XMM2))
178 return -ENODEV;
179
180 #ifdef CONFIG_AS_AVX2
181 poly1305_use_avx2 = boot_cpu_has(X86_FEATURE_AVX) &&
182 boot_cpu_has(X86_FEATURE_AVX2) &&
183 cpu_has_xfeatures(XFEATURE_MASK_SSE | XFEATURE_MASK_YMM, NULL);
184 alg.descsize = sizeof(struct poly1305_simd_desc_ctx);
185 if (poly1305_use_avx2)
186 alg.descsize += 10 * sizeof(u32);
187 #endif
188 return crypto_register_shash(&alg);
189 }
190
poly1305_simd_mod_exit(void)191 static void __exit poly1305_simd_mod_exit(void)
192 {
193 crypto_unregister_shash(&alg);
194 }
195
196 module_init(poly1305_simd_mod_init);
197 module_exit(poly1305_simd_mod_exit);
198
199 MODULE_LICENSE("GPL");
200 MODULE_AUTHOR("Martin Willi <martin@strongswan.org>");
201 MODULE_DESCRIPTION("Poly1305 authenticator");
202 MODULE_ALIAS_CRYPTO("poly1305");
203 MODULE_ALIAS_CRYPTO("poly1305-simd");
204