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_TYPE_SHASH | 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 }; 226