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 }; 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