drivers/crypto/vmx/ghash.c

   1 /**
   2  * GHASH routines supporting VMX instructions on the Power 8
   3  *
   4  * Copyright (C) 2015 International Business Machines Inc.
   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; version 2 only.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  18  *
  19  * Author: Marcelo Henrique Cerri <mhcerri@br.ibm.com>
  20  */
  21
  22 #include <linux/types.h>
  23 #include <linux/err.h>
  24 #include <linux/crypto.h>
  25 #include <linux/delay.h>
  26 #include <linux/hardirq.h>
  27 #include <asm/switch_to.h>
  28 #include <crypto/aes.h>
  29 #include <crypto/ghash.h>
  30 #include <crypto/scatterwalk.h>
  31 #include <crypto/internal/hash.h>
  32 #include <crypto/b128ops.h>
  33
  34 #define IN_INTERRUPT in_interrupt()
  35
  36 void gcm_init_p8(u128 htable[16], const u64 Xi[2]);
  37 void gcm_gmult_p8(u64 Xi[2], const u128 htable[16]);
  38 void gcm_ghash_p8(u64 Xi[2], const u128 htable[16],
  39                   const u8 *in, size_t len);
  40
  41 struct p8_ghash_ctx {
  42         u128 htable[16];
  43         struct crypto_shash *fallback;
  44 };
  45
  46 struct p8_ghash_desc_ctx {
  47         u64 shash[2];
  48         u8 buffer[GHASH_DIGEST_SIZE];
  49         int bytes;
  50         struct shash_desc fallback_desc;
  51 };
  52
  53 static int p8_ghash_init_tfm(struct crypto_tfm *tfm)
  54 {
  55         const char *alg = "ghash-generic";
  56         struct crypto_shash *fallback;
  57         struct crypto_shash *shash_tfm = __crypto_shash_cast(tfm);
  58         struct p8_ghash_ctx *ctx = crypto_tfm_ctx(tfm);
  59
  60         fallback = crypto_alloc_shash(alg, 0, CRYPTO_ALG_NEED_FALLBACK);
  61         if (IS_ERR(fallback)) {
  62                 printk(KERN_ERR
  63                        "Failed to allocate transformation for '%s': %ld\n",
  64                        alg, PTR_ERR(fallback));
  65                 return PTR_ERR(fallback);
  66         }
  67         printk(KERN_INFO "Using '%s' as fallback implementation.\n",
  68                crypto_tfm_alg_driver_name(crypto_shash_tfm(fallback)));
  69
  70         crypto_shash_set_flags(fallback,
  71                                crypto_shash_get_flags((struct crypto_shash
  72                                                        *) tfm));
  73
  74         /* Check if the descsize defined in the algorithm is still enough. */
  75         if (shash_tfm->descsize < sizeof(struct p8_ghash_desc_ctx)
  76             + crypto_shash_descsize(fallback)) {
  77                 printk(KERN_ERR
  78                        "Desc size of the fallback implementation (%s) does not match the expected value: %lu vs %u\n",
  79                        alg,
  80                        shash_tfm->descsize - sizeof(struct p8_ghash_desc_ctx),
  81                        crypto_shash_descsize(fallback));
  82                 return -EINVAL;
  83         }
  84         ctx->fallback = fallback;
  85
  86         return 0;
  87 }
  88
  89 static void p8_ghash_exit_tfm(struct crypto_tfm *tfm)
  90 {
  91         struct p8_ghash_ctx *ctx = crypto_tfm_ctx(tfm);
  92
  93         if (ctx->fallback) {
  94                 crypto_free_shash(ctx->fallback);
  95                 ctx->fallback = NULL;
  96         }
  97 }
  98
  99 static int p8_ghash_init(struct shash_desc *desc)
 100 {
 101         struct p8_ghash_ctx *ctx = crypto_tfm_ctx(crypto_shash_tfm(desc->tfm));
 102         struct p8_ghash_desc_ctx *dctx = shash_desc_ctx(desc);
 103
 104         dctx->bytes = 0;
 105         memset(dctx->shash, 0, GHASH_DIGEST_SIZE);
 106         dctx->fallback_desc.tfm = ctx->fallback;
 107         dctx->fallback_desc.flags = desc->flags;
 108         return crypto_shash_init(&dctx->fallback_desc);
 109 }
 110
 111 static int p8_ghash_setkey(struct crypto_shash *tfm, const u8 *key,
 112                            unsigned int keylen)
 113 {
 114         struct p8_ghash_ctx *ctx = crypto_tfm_ctx(crypto_shash_tfm(tfm));
 115
 116         if (keylen != GHASH_BLOCK_SIZE)
 117                 return -EINVAL;
 118
 119         preempt_disable();
 120         pagefault_disable();
 121         enable_kernel_vsx();
 122         gcm_init_p8(ctx->htable, (const u64 *) key);
 123         disable_kernel_vsx();
 124         pagefault_enable();
 125         preempt_enable();
 126         return crypto_shash_setkey(ctx->fallback, key, keylen);
 127 }
 128
 129 static int p8_ghash_update(struct shash_desc *desc,
 130                            const u8 *src, unsigned int srclen)
 131 {
 132         unsigned int len;
 133         struct p8_ghash_ctx *ctx = crypto_tfm_ctx(crypto_shash_tfm(desc->tfm));
 134         struct p8_ghash_desc_ctx *dctx = shash_desc_ctx(desc);
 135
 136         if (IN_INTERRUPT) {
 137                 return crypto_shash_update(&dctx->fallback_desc, src,
 138                                            srclen);
 139         } else {
 140                 if (dctx->bytes) {
 141                         if (dctx->bytes + srclen < GHASH_DIGEST_SIZE) {
 142                                 memcpy(dctx->buffer + dctx->bytes, src,
 143                                        srclen);
 144                                 dctx->bytes += srclen;
 145                                 return 0;
 146                         }
 147                         memcpy(dctx->buffer + dctx->bytes, src,
 148                                GHASH_DIGEST_SIZE - dctx->bytes);
 149                         preempt_disable();
 150                         pagefault_disable();
 151                         enable_kernel_vsx();
 152                         gcm_ghash_p8(dctx->shash, ctx->htable,
 153                                      dctx->buffer, GHASH_DIGEST_SIZE);
 154                         disable_kernel_vsx();
 155                         pagefault_enable();
 156                         preempt_enable();
 157                         src += GHASH_DIGEST_SIZE - dctx->bytes;
 158                         srclen -= GHASH_DIGEST_SIZE - dctx->bytes;
 159                         dctx->bytes = 0;
 160                 }
 161                 len = srclen & ~(GHASH_DIGEST_SIZE - 1);
 162                 if (len) {
 163                         preempt_disable();
 164                         pagefault_disable();
 165                         enable_kernel_vsx();
 166                         gcm_ghash_p8(dctx->shash, ctx->htable, src, len);
 167                         disable_kernel_vsx();
 168                         pagefault_enable();
 169                         preempt_enable();
 170                         src += len;
 171                         srclen -= len;
 172                 }
 173                 if (srclen) {
 174                         memcpy(dctx->buffer, src, srclen);
 175                         dctx->bytes = srclen;
 176                 }
 177                 return 0;
 178         }
 179 }
 180
 181 static int p8_ghash_final(struct shash_desc *desc, u8 *out)
 182 {
 183         int i;
 184         struct p8_ghash_ctx *ctx = crypto_tfm_ctx(crypto_shash_tfm(desc->tfm));
 185         struct p8_ghash_desc_ctx *dctx = shash_desc_ctx(desc);
 186
 187         if (IN_INTERRUPT) {
 188                 return crypto_shash_final(&dctx->fallback_desc, out);
 189         } else {
 190                 if (dctx->bytes) {
 191                         for (i = dctx->bytes; i < GHASH_DIGEST_SIZE; i++)
 192                                 dctx->buffer[i] = 0;
 193                         preempt_disable();
 194                         pagefault_disable();
 195                         enable_kernel_vsx();
 196                         gcm_ghash_p8(dctx->shash, ctx->htable,
 197                                      dctx->buffer, GHASH_DIGEST_SIZE);
 198                         disable_kernel_vsx();
 199                         pagefault_enable();
 200                         preempt_enable();
 201                         dctx->bytes = 0;
 202                 }
 203                 memcpy(out, dctx->shash, GHASH_DIGEST_SIZE);
 204                 return 0;
 205         }
 206 }
 207
 208 struct shash_alg p8_ghash_alg = {
 209         .digestsize = GHASH_DIGEST_SIZE,
 210         .init = p8_ghash_init,
 211         .update = p8_ghash_update,
 212         .final = p8_ghash_final,
 213         .setkey = p8_ghash_setkey,
 214         .descsize = sizeof(struct p8_ghash_desc_ctx)
 215                 + sizeof(struct ghash_desc_ctx),
 216         .base = {
 217                  .cra_name = "ghash",
 218                  .cra_driver_name = "p8_ghash",
 219                  .cra_priority = 1000,
 220                  .cra_flags = CRYPTO_ALG_TYPE_SHASH | CRYPTO_ALG_NEED_FALLBACK,
 221                  .cra_blocksize = GHASH_BLOCK_SIZE,
 222                  .cra_ctxsize = sizeof(struct p8_ghash_ctx),
 223                  .cra_module = THIS_MODULE,
 224                  .cra_init = p8_ghash_init_tfm,
 225                  .cra_exit = p8_ghash_exit_tfm,
 226         },
 227 };