arch/x86/crypto/ghash-clmulni-intel_glue.c

   1 /*
   2  * Accelerated GHASH implementation with Intel PCLMULQDQ-NI
   3  * instructions. This file contains glue code.
   4  *
   5  * Copyright (c) 2009 Intel Corp.
   6  *   Author: Huang Ying <ying.huang@intel.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify it
   9  * under the terms of the GNU General Public License version 2 as published
  10  * by the Free Software Foundation.
  11  */
  12
  13 #include <linux/err.h>
  14 #include <linux/module.h>
  15 #include <linux/init.h>
  16 #include <linux/kernel.h>
  17 #include <linux/crypto.h>
  18 #include <crypto/algapi.h>
  19 #include <crypto/cryptd.h>
  20 #include <crypto/gf128mul.h>
  21 #include <crypto/internal/hash.h>
  22 #include <asm/i387.h>
  23 #include <asm/cpu_device_id.h>
  24
  25 #define GHASH_BLOCK_SIZE        16
  26 #define GHASH_DIGEST_SIZE       16
  27
  28 void clmul_ghash_mul(char *dst, const u128 *shash);
  29
  30 void clmul_ghash_update(char *dst, const char *src, unsigned int srclen,
  31                         const u128 *shash);
  32
  33 struct ghash_async_ctx {
  34         struct cryptd_ahash *cryptd_tfm;
  35 };
  36
  37 struct ghash_ctx {
  38         u128 shash;
  39 };
  40
  41 struct ghash_desc_ctx {
  42         u8 buffer[GHASH_BLOCK_SIZE];
  43         u32 bytes;
  44 };
  45
  46 static int ghash_init(struct shash_desc *desc)
  47 {
  48         struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
  49
  50         memset(dctx, 0, sizeof(*dctx));
  51
  52         return 0;
  53 }
  54
  55 static int ghash_setkey(struct crypto_shash *tfm,
  56                         const u8 *key, unsigned int keylen)
  57 {
  58         struct ghash_ctx *ctx = crypto_shash_ctx(tfm);
  59         be128 *x = (be128 *)key;
  60         u64 a, b;
  61
  62         if (keylen != GHASH_BLOCK_SIZE) {
  63                 crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
  64                 return -EINVAL;
  65         }
  66
  67         /* perform multiplication by 'x' in GF(2^128) */
  68         a = be64_to_cpu(x->a);
  69         b = be64_to_cpu(x->b);
  70
  71         ctx->shash.a = (b << 1) | (a >> 63);
  72         ctx->shash.b = (a << 1) | (b >> 63);
  73
  74         if (a >> 63)
  75                 ctx->shash.b ^= ((u64)0xc2) << 56;
  76
  77         return 0;
  78 }
  79
  80 static int ghash_update(struct shash_desc *desc,
  81                          const u8 *src, unsigned int srclen)
  82 {
  83         struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
  84         struct ghash_ctx *ctx = crypto_shash_ctx(desc->tfm);
  85         u8 *dst = dctx->buffer;
  86
  87         kernel_fpu_begin();
  88         if (dctx->bytes) {
  89                 int n = min(srclen, dctx->bytes);
  90                 u8 *pos = dst + (GHASH_BLOCK_SIZE - dctx->bytes);
  91
  92                 dctx->bytes -= n;
  93                 srclen -= n;
  94
  95                 while (n--)
  96                         *pos++ ^= *src++;
  97
  98                 if (!dctx->bytes)
  99                         clmul_ghash_mul(dst, &ctx->shash);
 100         }
 101
 102         clmul_ghash_update(dst, src, srclen, &ctx->shash);
 103         kernel_fpu_end();
 104
 105         if (srclen & 0xf) {
 106                 src += srclen - (srclen & 0xf);
 107                 srclen &= 0xf;
 108                 dctx->bytes = GHASH_BLOCK_SIZE - srclen;
 109                 while (srclen--)
 110                         *dst++ ^= *src++;
 111         }
 112
 113         return 0;
 114 }
 115
 116 static void ghash_flush(struct ghash_ctx *ctx, struct ghash_desc_ctx *dctx)
 117 {
 118         u8 *dst = dctx->buffer;
 119
 120         if (dctx->bytes) {
 121                 u8 *tmp = dst + (GHASH_BLOCK_SIZE - dctx->bytes);
 122
 123                 while (dctx->bytes--)
 124                         *tmp++ ^= 0;
 125
 126                 kernel_fpu_begin();
 127                 clmul_ghash_mul(dst, &ctx->shash);
 128                 kernel_fpu_end();
 129         }
 130
 131         dctx->bytes = 0;
 132 }
 133
 134 static int ghash_final(struct shash_desc *desc, u8 *dst)
 135 {
 136         struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
 137         struct ghash_ctx *ctx = crypto_shash_ctx(desc->tfm);
 138         u8 *buf = dctx->buffer;
 139
 140         ghash_flush(ctx, dctx);
 141         memcpy(dst, buf, GHASH_BLOCK_SIZE);
 142
 143         return 0;
 144 }
 145
 146 static struct shash_alg ghash_alg = {
 147         .digestsize     = GHASH_DIGEST_SIZE,
 148         .init           = ghash_init,
 149         .update         = ghash_update,
 150         .final          = ghash_final,
 151         .setkey         = ghash_setkey,
 152         .descsize       = sizeof(struct ghash_desc_ctx),
 153         .base           = {
 154                 .cra_name               = "__ghash",
 155                 .cra_driver_name        = "__ghash-pclmulqdqni",
 156                 .cra_priority           = 0,
 157                 .cra_flags              = CRYPTO_ALG_TYPE_SHASH,
 158                 .cra_blocksize          = GHASH_BLOCK_SIZE,
 159                 .cra_ctxsize            = sizeof(struct ghash_ctx),
 160                 .cra_module             = THIS_MODULE,
 161         },
 162 };
 163
 164 static int ghash_async_init(struct ahash_request *req)
 165 {
 166         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 167         struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
 168         struct ahash_request *cryptd_req = ahash_request_ctx(req);
 169         struct cryptd_ahash *cryptd_tfm = ctx->cryptd_tfm;
 170
 171         if (!irq_fpu_usable()) {
 172                 memcpy(cryptd_req, req, sizeof(*req));
 173                 ahash_request_set_tfm(cryptd_req, &cryptd_tfm->base);
 174                 return crypto_ahash_init(cryptd_req);
 175         } else {
 176                 struct shash_desc *desc = cryptd_shash_desc(cryptd_req);
 177                 struct crypto_shash *child = cryptd_ahash_child(cryptd_tfm);
 178
 179                 desc->tfm = child;
 180                 desc->flags = req->base.flags;
 181                 return crypto_shash_init(desc);
 182         }
 183 }
 184
 185 static int ghash_async_update(struct ahash_request *req)
 186 {
 187         struct ahash_request *cryptd_req = ahash_request_ctx(req);
 188
 189         if (!irq_fpu_usable()) {
 190                 struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 191                 struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
 192                 struct cryptd_ahash *cryptd_tfm = ctx->cryptd_tfm;
 193
 194                 memcpy(cryptd_req, req, sizeof(*req));
 195                 ahash_request_set_tfm(cryptd_req, &cryptd_tfm->base);
 196                 return crypto_ahash_update(cryptd_req);
 197         } else {
 198                 struct shash_desc *desc = cryptd_shash_desc(cryptd_req);
 199                 return shash_ahash_update(req, desc);
 200         }
 201 }
 202
 203 static int ghash_async_final(struct ahash_request *req)
 204 {
 205         struct ahash_request *cryptd_req = ahash_request_ctx(req);
 206
 207         if (!irq_fpu_usable()) {
 208                 struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 209                 struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
 210                 struct cryptd_ahash *cryptd_tfm = ctx->cryptd_tfm;
 211
 212                 memcpy(cryptd_req, req, sizeof(*req));
 213                 ahash_request_set_tfm(cryptd_req, &cryptd_tfm->base);
 214                 return crypto_ahash_final(cryptd_req);
 215         } else {
 216                 struct shash_desc *desc = cryptd_shash_desc(cryptd_req);
 217                 return crypto_shash_final(desc, req->result);
 218         }
 219 }
 220
 221 static int ghash_async_digest(struct ahash_request *req)
 222 {
 223         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 224         struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
 225         struct ahash_request *cryptd_req = ahash_request_ctx(req);
 226         struct cryptd_ahash *cryptd_tfm = ctx->cryptd_tfm;
 227
 228         if (!irq_fpu_usable()) {
 229                 memcpy(cryptd_req, req, sizeof(*req));
 230                 ahash_request_set_tfm(cryptd_req, &cryptd_tfm->base);
 231                 return crypto_ahash_digest(cryptd_req);
 232         } else {
 233                 struct shash_desc *desc = cryptd_shash_desc(cryptd_req);
 234                 struct crypto_shash *child = cryptd_ahash_child(cryptd_tfm);
 235
 236                 desc->tfm = child;
 237                 desc->flags = req->base.flags;
 238                 return shash_ahash_digest(req, desc);
 239         }
 240 }
 241
 242 static int ghash_async_setkey(struct crypto_ahash *tfm, const u8 *key,
 243                               unsigned int keylen)
 244 {
 245         struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
 246         struct crypto_ahash *child = &ctx->cryptd_tfm->base;
 247         int err;
 248
 249         crypto_ahash_clear_flags(child, CRYPTO_TFM_REQ_MASK);
 250         crypto_ahash_set_flags(child, crypto_ahash_get_flags(tfm)
 251                                & CRYPTO_TFM_REQ_MASK);
 252         err = crypto_ahash_setkey(child, key, keylen);
 253         crypto_ahash_set_flags(tfm, crypto_ahash_get_flags(child)
 254                                & CRYPTO_TFM_RES_MASK);
 255
 256         return err;
 257 }
 258
 259 static int ghash_async_init_tfm(struct crypto_tfm *tfm)
 260 {
 261         struct cryptd_ahash *cryptd_tfm;
 262         struct ghash_async_ctx *ctx = crypto_tfm_ctx(tfm);
 263
 264         cryptd_tfm = cryptd_alloc_ahash("__ghash-pclmulqdqni", 0, 0);
 265         if (IS_ERR(cryptd_tfm))
 266                 return PTR_ERR(cryptd_tfm);
 267         ctx->cryptd_tfm = cryptd_tfm;
 268         crypto_ahash_set_reqsize(__crypto_ahash_cast(tfm),
 269                                  sizeof(struct ahash_request) +
 270                                  crypto_ahash_reqsize(&cryptd_tfm->base));
 271
 272         return 0;
 273 }
 274
 275 static void ghash_async_exit_tfm(struct crypto_tfm *tfm)
 276 {
 277         struct ghash_async_ctx *ctx = crypto_tfm_ctx(tfm);
 278
 279         cryptd_free_ahash(ctx->cryptd_tfm);
 280 }
 281
 282 static struct ahash_alg ghash_async_alg = {
 283         .init           = ghash_async_init,
 284         .update         = ghash_async_update,
 285         .final          = ghash_async_final,
 286         .setkey         = ghash_async_setkey,
 287         .digest         = ghash_async_digest,
 288         .halg = {
 289                 .digestsize     = GHASH_DIGEST_SIZE,
 290                 .base = {
 291                         .cra_name               = "ghash",
 292                         .cra_driver_name        = "ghash-clmulni",
 293                         .cra_priority           = 400,
 294                         .cra_flags              = CRYPTO_ALG_TYPE_AHASH | CRYPTO_ALG_ASYNC,
 295                         .cra_blocksize          = GHASH_BLOCK_SIZE,
 296                         .cra_type               = &crypto_ahash_type,
 297                         .cra_module             = THIS_MODULE,
 298                         .cra_init               = ghash_async_init_tfm,
 299                         .cra_exit               = ghash_async_exit_tfm,
 300                 },
 301         },
 302 };
 303
 304 static const struct x86_cpu_id pcmul_cpu_id[] = {
 305         X86_FEATURE_MATCH(X86_FEATURE_PCLMULQDQ), /* Pickle-Mickle-Duck */
 306         {}
 307 };
 308 MODULE_DEVICE_TABLE(x86cpu, pcmul_cpu_id);
 309
 310 static int __init ghash_pclmulqdqni_mod_init(void)
 311 {
 312         int err;
 313
 314         if (!x86_match_cpu(pcmul_cpu_id))
 315                 return -ENODEV;
 316
 317         err = crypto_register_shash(&ghash_alg);
 318         if (err)
 319                 goto err_out;
 320         err = crypto_register_ahash(&ghash_async_alg);
 321         if (err)
 322                 goto err_shash;
 323
 324         return 0;
 325
 326 err_shash:
 327         crypto_unregister_shash(&ghash_alg);
 328 err_out:
 329         return err;
 330 }
 331
 332 static void __exit ghash_pclmulqdqni_mod_exit(void)
 333 {
 334         crypto_unregister_ahash(&ghash_async_alg);
 335         crypto_unregister_shash(&ghash_alg);
 336 }
 337
 338 module_init(ghash_pclmulqdqni_mod_init);
 339 module_exit(ghash_pclmulqdqni_mod_exit);
 340
 341 MODULE_LICENSE("GPL");
 342 MODULE_DESCRIPTION("GHASH Message Digest Algorithm, "
 343                    "acclerated by PCLMULQDQ-NI");
 344 MODULE_ALIAS_CRYPTO("ghash");