arch/x86/crypto/poly1305_glue.c

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