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
  68         crypto_shash_set_flags(fallback,
  69                                crypto_shash_get_flags((struct crypto_shash
  70                                                        *) tfm));
  71
  72         /* Check if the descsize defined in the algorithm is still enough. */
  73         if (shash_tfm->descsize < sizeof(struct p8_ghash_desc_ctx)
  74             + crypto_shash_descsize(fallback)) {
  75                 printk(KERN_ERR
  76                        "Desc size of the fallback implementation (%s) does not match the expected value: %lu vs %u\n",
  77                        alg,
  78                        shash_tfm->descsize - sizeof(struct p8_ghash_desc_ctx),
  79                        crypto_shash_descsize(fallback));
  80                 return -EINVAL;
  81         }
  82         ctx->fallback = fallback;
  83
  84         return 0;
  85 }
  86
  87 static void p8_ghash_exit_tfm(struct crypto_tfm *tfm)
  88 {
  89         struct p8_ghash_ctx *ctx = crypto_tfm_ctx(tfm);
  90
  91         if (ctx->fallback) {
  92                 crypto_free_shash(ctx->fallback);
  93                 ctx->fallback = NULL;
  94         }
  95 }
  96
  97 static int p8_ghash_init(struct shash_desc *desc)
  98 {
  99         struct p8_ghash_ctx *ctx = crypto_tfm_ctx(crypto_shash_tfm(desc->tfm));
 100         struct p8_ghash_desc_ctx *dctx = shash_desc_ctx(desc);
 101
 102         dctx->bytes = 0;
 103         memset(dctx->shash, 0, GHASH_DIGEST_SIZE);
 104         dctx->fallback_desc.tfm = ctx->fallback;
 105         dctx->fallback_desc.flags = desc->flags;
 106         return crypto_shash_init(&dctx->fallback_desc);
 107 }
 108
 109 static int p8_ghash_setkey(struct crypto_shash *tfm, const u8 *key,
 110                            unsigned int keylen)
 111 {
 112         struct p8_ghash_ctx *ctx = crypto_tfm_ctx(crypto_shash_tfm(tfm));
 113
 114         if (keylen != GHASH_BLOCK_SIZE)
 115                 return -EINVAL;
 116
 117         preempt_disable();
 118         pagefault_disable();
 119         enable_kernel_vsx();
 120         gcm_init_p8(ctx->htable, (const u64 *) key);
 121         disable_kernel_vsx();
 122         pagefault_enable();
 123         preempt_enable();
 124         return crypto_shash_setkey(ctx->fallback, key, keylen);
 125 }
 126
 127 static int p8_ghash_update(struct shash_desc *desc,
 128                            const u8 *src, unsigned int srclen)
 129 {
 130         unsigned int len;
 131         struct p8_ghash_ctx *ctx = crypto_tfm_ctx(crypto_shash_tfm(desc->tfm));
 132         struct p8_ghash_desc_ctx *dctx = shash_desc_ctx(desc);
 133
 134         if (IN_INTERRUPT) {
 135                 return crypto_shash_update(&dctx->fallback_desc, src,
 136                                            srclen);
 137         } else {
 138                 if (dctx->bytes) {
 139                         if (dctx->bytes + srclen < GHASH_DIGEST_SIZE) {
 140                                 memcpy(dctx->buffer + dctx->bytes, src,
 141                                        srclen);
 142                                 dctx->bytes += srclen;
 143                                 return 0;
 144                         }
 145                         memcpy(dctx->buffer + dctx->bytes, src,
 146                                GHASH_DIGEST_SIZE - dctx->bytes);
 147                         preempt_disable();
 148                         pagefault_disable();
 149                         enable_kernel_vsx();
 150                         gcm_ghash_p8(dctx->shash, ctx->htable,
 151                                      dctx->buffer, GHASH_DIGEST_SIZE);
 152                         disable_kernel_vsx();
 153                         pagefault_enable();
 154                         preempt_enable();
 155                         src += GHASH_DIGEST_SIZE - dctx->bytes;
 156                         srclen -= GHASH_DIGEST_SIZE - dctx->bytes;
 157                         dctx->bytes = 0;
 158                 }
 159                 len = srclen & ~(GHASH_DIGEST_SIZE - 1);
 160                 if (len) {
 161                         preempt_disable();
 162                         pagefault_disable();
 163                         enable_kernel_vsx();
 164                         gcm_ghash_p8(dctx->shash, ctx->htable, src, len);
 165                         disable_kernel_vsx();
 166                         pagefault_enable();
 167                         preempt_enable();
 168                         src += len;
 169                         srclen -= len;
 170                 }
 171                 if (srclen) {
 172                         memcpy(dctx->buffer, src, srclen);
 173                         dctx->bytes = srclen;
 174                 }
 175                 return 0;
 176         }
 177 }
 178
 179 static int p8_ghash_final(struct shash_desc *desc, u8 *out)
 180 {
 181         int i;
 182         struct p8_ghash_ctx *ctx = crypto_tfm_ctx(crypto_shash_tfm(desc->tfm));
 183         struct p8_ghash_desc_ctx *dctx = shash_desc_ctx(desc);
 184
 185         if (IN_INTERRUPT) {
 186                 return crypto_shash_final(&dctx->fallback_desc, out);
 187         } else {
 188                 if (dctx->bytes) {
 189                         for (i = dctx->bytes; i < GHASH_DIGEST_SIZE; i++)
 190                                 dctx->buffer[i] = 0;
 191                         preempt_disable();
 192                         pagefault_disable();
 193                         enable_kernel_vsx();
 194                         gcm_ghash_p8(dctx->shash, ctx->htable,
 195                                      dctx->buffer, GHASH_DIGEST_SIZE);
 196                         disable_kernel_vsx();
 197                         pagefault_enable();
 198                         preempt_enable();
 199                         dctx->bytes = 0;
 200                 }
 201                 memcpy(out, dctx->shash, GHASH_DIGEST_SIZE);
 202                 return 0;
 203         }
 204 }
 205
 206 struct shash_alg p8_ghash_alg = {
 207         .digestsize = GHASH_DIGEST_SIZE,
 208         .init = p8_ghash_init,
 209         .update = p8_ghash_update,
 210         .final = p8_ghash_final,
 211         .setkey = p8_ghash_setkey,
 212         .descsize = sizeof(struct p8_ghash_desc_ctx)
 213                 + sizeof(struct ghash_desc_ctx),
 214         .base = {
 215                  .cra_name = "ghash",
 216                  .cra_driver_name = "p8_ghash",
 217                  .cra_priority = 1000,
 218                  .cra_flags = CRYPTO_ALG_NEED_FALLBACK,
 219                  .cra_blocksize = GHASH_BLOCK_SIZE,
 220                  .cra_ctxsize = sizeof(struct p8_ghash_ctx),
 221                  .cra_module = THIS_MODULE,
 222                  .cra_init = p8_ghash_init_tfm,
 223                  .cra_exit = p8_ghash_exit_tfm,
 224         },
 225 };