kernel/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 "Failed to allocate transformation for '%s': %ld\n",
  71                 alg, PTR_ERR(fallback));
  72         return PTR_ERR(fallback);
  73     }
  74     printk(KERN_INFO "Using '%s' as fallback implementation.\n",
  75             crypto_tfm_alg_driver_name(crypto_shash_tfm(fallback)));
  76
  77     crypto_shash_set_flags(fallback,
  78             crypto_shash_get_flags((struct crypto_shash *) tfm));
  79     ctx->fallback = fallback;
  80
  81     shash_tfm->descsize = sizeof(struct p8_ghash_desc_ctx)
  82         + crypto_shash_descsize(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_KEY_LEN)
 115         return -EINVAL;
 116
 117     pagefault_disable();
 118     enable_kernel_altivec();
 119     enable_kernel_vsx();
 120     enable_kernel_fp();
 121     gcm_init_p8(ctx->htable, (const u64 *) key);
 122     pagefault_enable();
 123     return crypto_shash_setkey(ctx->fallback, key, keylen);
 124 }
 125
 126 static int p8_ghash_update(struct shash_desc *desc,
 127         const u8 *src, unsigned int srclen)
 128 {
 129     unsigned int len;
 130     struct p8_ghash_ctx *ctx = crypto_tfm_ctx(crypto_shash_tfm(desc->tfm));
 131     struct p8_ghash_desc_ctx *dctx = shash_desc_ctx(desc);
 132
 133     if (IN_INTERRUPT) {
 134         return crypto_shash_update(&dctx->fallback_desc, src, srclen);
 135     } else {
 136         if (dctx->bytes) {
 137             if (dctx->bytes + srclen < GHASH_DIGEST_SIZE) {
 138                 memcpy(dctx->buffer + dctx->bytes, src, srclen);
 139                 dctx->bytes += srclen;
 140                 return 0;
 141             }
 142             memcpy(dctx->buffer + dctx->bytes, src,
 143                     GHASH_DIGEST_SIZE - dctx->bytes);
 144             pagefault_disable();
 145             enable_kernel_altivec();
 146             enable_kernel_vsx();
 147             enable_kernel_fp();
 148             gcm_ghash_p8(dctx->shash, ctx->htable, dctx->buffer,
 149                     GHASH_DIGEST_SIZE);
 150             pagefault_enable();
 151             src += GHASH_DIGEST_SIZE - dctx->bytes;
 152             srclen -= GHASH_DIGEST_SIZE - dctx->bytes;
 153             dctx->bytes = 0;
 154         }
 155         len = srclen & ~(GHASH_DIGEST_SIZE - 1);
 156         if (len) {
 157             pagefault_disable();
 158             enable_kernel_altivec();
 159             enable_kernel_vsx();
 160             enable_kernel_fp();
 161             gcm_ghash_p8(dctx->shash, ctx->htable, src, len);
 162             pagefault_enable();
 163             src += len;
 164             srclen -= len;
 165         }
 166         if (srclen) {
 167             memcpy(dctx->buffer, src, srclen);
 168             dctx->bytes = srclen;
 169         }
 170         return 0;
 171     }
 172 }
 173
 174 static int p8_ghash_final(struct shash_desc *desc, u8 *out)
 175 {
 176     int i;
 177     struct p8_ghash_ctx *ctx = crypto_tfm_ctx(crypto_shash_tfm(desc->tfm));
 178     struct p8_ghash_desc_ctx *dctx = shash_desc_ctx(desc);
 179
 180     if (IN_INTERRUPT) {
 181         return crypto_shash_final(&dctx->fallback_desc, out);
 182     } else {
 183         if (dctx->bytes) {
 184             for (i = dctx->bytes; i < GHASH_DIGEST_SIZE; i++)
 185                 dctx->buffer[i] = 0;
 186             pagefault_disable();
 187             enable_kernel_altivec();
 188             enable_kernel_vsx();
 189             enable_kernel_fp();
 190             gcm_ghash_p8(dctx->shash, ctx->htable, dctx->buffer,
 191                     GHASH_DIGEST_SIZE);
 192             pagefault_enable();
 193             dctx->bytes = 0;
 194         }
 195         memcpy(out, dctx->shash, GHASH_DIGEST_SIZE);
 196         return 0;
 197     }
 198 }
 199
 200 struct shash_alg p8_ghash_alg = {
 201     .digestsize = GHASH_DIGEST_SIZE,
 202     .init       = p8_ghash_init,
 203     .update     = p8_ghash_update,
 204     .final      = p8_ghash_final,
 205     .setkey     = p8_ghash_setkey,
 206     .descsize   = sizeof(struct p8_ghash_desc_ctx),
 207     .base       = {
 208         .cra_name = "ghash",
 209         .cra_driver_name = "p8_ghash",
 210         .cra_priority = 1000,
 211         .cra_flags = CRYPTO_ALG_TYPE_SHASH | CRYPTO_ALG_NEED_FALLBACK,
 212         .cra_blocksize = GHASH_BLOCK_SIZE,
 213         .cra_ctxsize = sizeof(struct p8_ghash_ctx),
 214         .cra_module = THIS_MODULE,
 215         .cra_init = p8_ghash_init_tfm,
 216         .cra_exit = p8_ghash_exit_tfm,
 217     },
 218 };