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/scatterwalk.h>
  30 #include <crypto/internal/hash.h>
  31 #include <crypto/b128ops.h>
  32
  33 #define IN_INTERRUPT in_interrupt()
  34
  35 #define GHASH_BLOCK_SIZE (16)
  36 #define GHASH_DIGEST_SIZE (16)
  37 #define GHASH_KEY_LEN (16)
  38
  39 void gcm_init_p8(u128 htable[16], const u64 Xi[2]);
  40 void gcm_gmult_p8(u64 Xi[2], const u128 htable[16]);
  41 void gcm_ghash_p8(u64 Xi[2], const u128 htable[16],
  42                   const u8 *in, size_t len);
  43
  44 struct p8_ghash_ctx {
  45         u128 htable[16];
  46         struct crypto_shash *fallback;
  47 };
  48
  49 struct p8_ghash_desc_ctx {
  50         u64 shash[2];
  51         u8 buffer[GHASH_DIGEST_SIZE];
  52         int bytes;
  53         struct shash_desc fallback_desc;
  54 };
  55
  56 static int p8_ghash_init_tfm(struct crypto_tfm *tfm)
  57 {
  58         const char *alg;
  59         struct crypto_shash *fallback;
  60         struct crypto_shash *shash_tfm = __crypto_shash_cast(tfm);
  61         struct p8_ghash_ctx *ctx = crypto_tfm_ctx(tfm);
  62
  63         if (!(alg = crypto_tfm_alg_name(tfm))) {
  64                 printk(KERN_ERR "Failed to get algorithm name.\n");
  65                 return -ENOENT;
  66         }
  67
  68         fallback = crypto_alloc_shash(alg, 0, CRYPTO_ALG_NEED_FALLBACK);
  69         if (IS_ERR(fallback)) {
  70                 printk(KERN_ERR
  71                        "Failed to allocate transformation for '%s': %ld\n",
  72                        alg, PTR_ERR(fallback));
  73                 return PTR_ERR(fallback);
  74         }
  75         printk(KERN_INFO "Using '%s' as fallback implementation.\n",
  76                crypto_tfm_alg_driver_name(crypto_shash_tfm(fallback)));
  77
  78         crypto_shash_set_flags(fallback,
  79                                crypto_shash_get_flags((struct crypto_shash
  80                                                        *) tfm));
  81         ctx->fallback = fallback;
  82
  83         shash_tfm->descsize = sizeof(struct p8_ghash_desc_ctx)
  84             + crypto_shash_descsize(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_KEY_LEN)
 117                 return -EINVAL;
 118
 119         preempt_disable();
 120         pagefault_disable();
 121         enable_kernel_altivec();
 122         enable_kernel_vsx();
 123         enable_kernel_fp();
 124         gcm_init_p8(ctx->htable, (const u64 *) key);
 125         pagefault_enable();
 126         preempt_enable();
 127         return crypto_shash_setkey(ctx->fallback, key, keylen);
 128 }
 129
 130 static int p8_ghash_update(struct shash_desc *desc,
 131                            const u8 *src, unsigned int srclen)
 132 {
 133         unsigned int len;
 134         struct p8_ghash_ctx *ctx = crypto_tfm_ctx(crypto_shash_tfm(desc->tfm));
 135         struct p8_ghash_desc_ctx *dctx = shash_desc_ctx(desc);
 136
 137         if (IN_INTERRUPT) {
 138                 return crypto_shash_update(&dctx->fallback_desc, src,
 139                                            srclen);
 140         } else {
 141                 if (dctx->bytes) {
 142                         if (dctx->bytes + srclen < GHASH_DIGEST_SIZE) {
 143                                 memcpy(dctx->buffer + dctx->bytes, src,
 144                                        srclen);
 145                                 dctx->bytes += srclen;
 146                                 return 0;
 147                         }
 148                         memcpy(dctx->buffer + dctx->bytes, src,
 149                                GHASH_DIGEST_SIZE - dctx->bytes);
 150                         preempt_disable();
 151                         pagefault_disable();
 152                         enable_kernel_altivec();
 153                         enable_kernel_vsx();
 154                         enable_kernel_fp();
 155                         gcm_ghash_p8(dctx->shash, ctx->htable,
 156                                      dctx->buffer, GHASH_DIGEST_SIZE);
 157                         pagefault_enable();
 158                         preempt_enable();
 159                         src += GHASH_DIGEST_SIZE - dctx->bytes;
 160                         srclen -= GHASH_DIGEST_SIZE - dctx->bytes;
 161                         dctx->bytes = 0;
 162                 }
 163                 len = srclen & ~(GHASH_DIGEST_SIZE - 1);
 164                 if (len) {
 165                         preempt_disable();
 166                         pagefault_disable();
 167                         enable_kernel_altivec();
 168                         enable_kernel_vsx();
 169                         enable_kernel_fp();
 170                         gcm_ghash_p8(dctx->shash, ctx->htable, src, len);
 171                         pagefault_enable();
 172                         preempt_enable();
 173                         src += len;
 174                         srclen -= len;
 175                 }
 176                 if (srclen) {
 177                         memcpy(dctx->buffer, src, srclen);
 178                         dctx->bytes = srclen;
 179                 }
 180                 return 0;
 181         }
 182 }
 183
 184 static int p8_ghash_final(struct shash_desc *desc, u8 *out)
 185 {
 186         int i;
 187         struct p8_ghash_ctx *ctx = crypto_tfm_ctx(crypto_shash_tfm(desc->tfm));
 188         struct p8_ghash_desc_ctx *dctx = shash_desc_ctx(desc);
 189
 190         if (IN_INTERRUPT) {
 191                 return crypto_shash_final(&dctx->fallback_desc, out);
 192         } else {
 193                 if (dctx->bytes) {
 194                         for (i = dctx->bytes; i < GHASH_DIGEST_SIZE; i++)
 195                                 dctx->buffer[i] = 0;
 196                         preempt_disable();
 197                         pagefault_disable();
 198                         enable_kernel_altivec();
 199                         enable_kernel_vsx();
 200                         enable_kernel_fp();
 201                         gcm_ghash_p8(dctx->shash, ctx->htable,
 202                                      dctx->buffer, GHASH_DIGEST_SIZE);
 203                         pagefault_enable();
 204                         preempt_enable();
 205                         dctx->bytes = 0;
 206                 }
 207                 memcpy(out, dctx->shash, GHASH_DIGEST_SIZE);
 208                 return 0;
 209         }
 210 }
 211
 212 struct shash_alg p8_ghash_alg = {
 213         .digestsize = GHASH_DIGEST_SIZE,
 214         .init = p8_ghash_init,
 215         .update = p8_ghash_update,
 216         .final = p8_ghash_final,
 217         .setkey = p8_ghash_setkey,
 218         .descsize = sizeof(struct p8_ghash_desc_ctx),
 219         .base = {
 220                  .cra_name = "ghash",
 221                  .cra_driver_name = "p8_ghash",
 222                  .cra_priority = 1000,
 223                  .cra_flags = CRYPTO_ALG_TYPE_SHASH | CRYPTO_ALG_NEED_FALLBACK,
 224                  .cra_blocksize = GHASH_BLOCK_SIZE,
 225                  .cra_ctxsize = sizeof(struct p8_ghash_ctx),
 226                  .cra_module = THIS_MODULE,
 227                  .cra_init = p8_ghash_init_tfm,
 228                  .cra_exit = p8_ghash_exit_tfm,
 229         },
 230 };