1 /* 2 * Glue code for SHA-256 implementation for SPE instructions (PPC) 3 * 4 * Based on generic implementation. The assembler module takes care 5 * about the SPE registers so it can run from interrupt context. 6 * 7 * Copyright (c) 2015 Markus Stockhausen <stockhausen@collogia.de> 8 * 9 * This program is free software; you can redistribute it and/or modify it 10 * under the terms of the GNU General Public License as published by the Free 11 * Software Foundation; either version 2 of the License, or (at your option) 12 * any later version. 13 * 14 */ 15 16 #include <crypto/internal/hash.h> 17 #include <linux/init.h> 18 #include <linux/module.h> 19 #include <linux/mm.h> 20 #include <linux/cryptohash.h> 21 #include <linux/types.h> 22 #include <crypto/sha.h> 23 #include <asm/byteorder.h> 24 #include <asm/switch_to.h> 25 #include <linux/hardirq.h> 26 27 /* 28 * MAX_BYTES defines the number of bytes that are allowed to be processed 29 * between preempt_disable() and preempt_enable(). SHA256 takes ~2,000 30 * operations per 64 bytes. e500 cores can issue two arithmetic instructions 31 * per clock cycle using one 32/64 bit unit (SU1) and one 32 bit unit (SU2). 32 * Thus 1KB of input data will need an estimated maximum of 18,000 cycles. 33 * Headroom for cache misses included. Even with the low end model clocked 34 * at 667 MHz this equals to a critical time window of less than 27us. 35 * 36 */ 37 #define MAX_BYTES 1024 38 39 extern void ppc_spe_sha256_transform(u32 *state, const u8 *src, u32 blocks); 40 41 static void spe_begin(void) 42 { 43 /* We just start SPE operations and will save SPE registers later. */ 44 preempt_disable(); 45 enable_kernel_spe(); 46 } 47 48 static void spe_end(void) 49 { 50 /* reenable preemption */ 51 preempt_enable(); 52 } 53 54 static inline void ppc_sha256_clear_context(struct sha256_state *sctx) 55 { 56 int count = sizeof(struct sha256_state) >> 2; 57 u32 *ptr = (u32 *)sctx; 58 59 /* make sure we can clear the fast way */ 60 BUILD_BUG_ON(sizeof(struct sha256_state) % 4); 61 do { *ptr++ = 0; } while (--count); 62 } 63 64 static int ppc_spe_sha256_init(struct shash_desc *desc) 65 { 66 struct sha256_state *sctx = shash_desc_ctx(desc); 67 68 sctx->state[0] = SHA256_H0; 69 sctx->state[1] = SHA256_H1; 70 sctx->state[2] = SHA256_H2; 71 sctx->state[3] = SHA256_H3; 72 sctx->state[4] = SHA256_H4; 73 sctx->state[5] = SHA256_H5; 74 sctx->state[6] = SHA256_H6; 75 sctx->state[7] = SHA256_H7; 76 sctx->count = 0; 77 78 return 0; 79 } 80 81 static int ppc_spe_sha224_init(struct shash_desc *desc) 82 { 83 struct sha256_state *sctx = shash_desc_ctx(desc); 84 85 sctx->state[0] = SHA224_H0; 86 sctx->state[1] = SHA224_H1; 87 sctx->state[2] = SHA224_H2; 88 sctx->state[3] = SHA224_H3; 89 sctx->state[4] = SHA224_H4; 90 sctx->state[5] = SHA224_H5; 91 sctx->state[6] = SHA224_H6; 92 sctx->state[7] = SHA224_H7; 93 sctx->count = 0; 94 95 return 0; 96 } 97 98 static int ppc_spe_sha256_update(struct shash_desc *desc, const u8 *data, 99 unsigned int len) 100 { 101 struct sha256_state *sctx = shash_desc_ctx(desc); 102 const unsigned int offset = sctx->count & 0x3f; 103 const unsigned int avail = 64 - offset; 104 unsigned int bytes; 105 const u8 *src = data; 106 107 if (avail > len) { 108 sctx->count += len; 109 memcpy((char *)sctx->buf + offset, src, len); 110 return 0; 111 } 112 113 sctx->count += len; 114 115 if (offset) { 116 memcpy((char *)sctx->buf + offset, src, avail); 117 118 spe_begin(); 119 ppc_spe_sha256_transform(sctx->state, (const u8 *)sctx->buf, 1); 120 spe_end(); 121 122 len -= avail; 123 src += avail; 124 } 125 126 while (len > 63) { 127 /* cut input data into smaller blocks */ 128 bytes = (len > MAX_BYTES) ? MAX_BYTES : len; 129 bytes = bytes & ~0x3f; 130 131 spe_begin(); 132 ppc_spe_sha256_transform(sctx->state, src, bytes >> 6); 133 spe_end(); 134 135 src += bytes; 136 len -= bytes; 137 }; 138 139 memcpy((char *)sctx->buf, src, len); 140 return 0; 141 } 142 143 static int ppc_spe_sha256_final(struct shash_desc *desc, u8 *out) 144 { 145 struct sha256_state *sctx = shash_desc_ctx(desc); 146 const unsigned int offset = sctx->count & 0x3f; 147 char *p = (char *)sctx->buf + offset; 148 int padlen; 149 __be64 *pbits = (__be64 *)(((char *)&sctx->buf) + 56); 150 __be32 *dst = (__be32 *)out; 151 152 padlen = 55 - offset; 153 *p++ = 0x80; 154 155 spe_begin(); 156 157 if (padlen < 0) { 158 memset(p, 0x00, padlen + sizeof (u64)); 159 ppc_spe_sha256_transform(sctx->state, sctx->buf, 1); 160 p = (char *)sctx->buf; 161 padlen = 56; 162 } 163 164 memset(p, 0, padlen); 165 *pbits = cpu_to_be64(sctx->count << 3); 166 ppc_spe_sha256_transform(sctx->state, sctx->buf, 1); 167 168 spe_end(); 169 170 dst[0] = cpu_to_be32(sctx->state[0]); 171 dst[1] = cpu_to_be32(sctx->state[1]); 172 dst[2] = cpu_to_be32(sctx->state[2]); 173 dst[3] = cpu_to_be32(sctx->state[3]); 174 dst[4] = cpu_to_be32(sctx->state[4]); 175 dst[5] = cpu_to_be32(sctx->state[5]); 176 dst[6] = cpu_to_be32(sctx->state[6]); 177 dst[7] = cpu_to_be32(sctx->state[7]); 178 179 ppc_sha256_clear_context(sctx); 180 return 0; 181 } 182 183 static int ppc_spe_sha224_final(struct shash_desc *desc, u8 *out) 184 { 185 u32 D[SHA256_DIGEST_SIZE >> 2]; 186 __be32 *dst = (__be32 *)out; 187 188 ppc_spe_sha256_final(desc, (u8 *)D); 189 190 /* avoid bytewise memcpy */ 191 dst[0] = D[0]; 192 dst[1] = D[1]; 193 dst[2] = D[2]; 194 dst[3] = D[3]; 195 dst[4] = D[4]; 196 dst[5] = D[5]; 197 dst[6] = D[6]; 198 199 /* clear sensitive data */ 200 memzero_explicit(D, SHA256_DIGEST_SIZE); 201 return 0; 202 } 203 204 static int ppc_spe_sha256_export(struct shash_desc *desc, void *out) 205 { 206 struct sha256_state *sctx = shash_desc_ctx(desc); 207 208 memcpy(out, sctx, sizeof(*sctx)); 209 return 0; 210 } 211 212 static int ppc_spe_sha256_import(struct shash_desc *desc, const void *in) 213 { 214 struct sha256_state *sctx = shash_desc_ctx(desc); 215 216 memcpy(sctx, in, sizeof(*sctx)); 217 return 0; 218 } 219 220 static struct shash_alg algs[2] = { { 221 .digestsize = SHA256_DIGEST_SIZE, 222 .init = ppc_spe_sha256_init, 223 .update = ppc_spe_sha256_update, 224 .final = ppc_spe_sha256_final, 225 .export = ppc_spe_sha256_export, 226 .import = ppc_spe_sha256_import, 227 .descsize = sizeof(struct sha256_state), 228 .statesize = sizeof(struct sha256_state), 229 .base = { 230 .cra_name = "sha256", 231 .cra_driver_name= "sha256-ppc-spe", 232 .cra_priority = 300, 233 .cra_flags = CRYPTO_ALG_TYPE_SHASH, 234 .cra_blocksize = SHA256_BLOCK_SIZE, 235 .cra_module = THIS_MODULE, 236 } 237 }, { 238 .digestsize = SHA224_DIGEST_SIZE, 239 .init = ppc_spe_sha224_init, 240 .update = ppc_spe_sha256_update, 241 .final = ppc_spe_sha224_final, 242 .export = ppc_spe_sha256_export, 243 .import = ppc_spe_sha256_import, 244 .descsize = sizeof(struct sha256_state), 245 .statesize = sizeof(struct sha256_state), 246 .base = { 247 .cra_name = "sha224", 248 .cra_driver_name= "sha224-ppc-spe", 249 .cra_priority = 300, 250 .cra_flags = CRYPTO_ALG_TYPE_SHASH, 251 .cra_blocksize = SHA224_BLOCK_SIZE, 252 .cra_module = THIS_MODULE, 253 } 254 } }; 255 256 static int __init ppc_spe_sha256_mod_init(void) 257 { 258 return crypto_register_shashes(algs, ARRAY_SIZE(algs)); 259 } 260 261 static void __exit ppc_spe_sha256_mod_fini(void) 262 { 263 crypto_unregister_shashes(algs, ARRAY_SIZE(algs)); 264 } 265 266 module_init(ppc_spe_sha256_mod_init); 267 module_exit(ppc_spe_sha256_mod_fini); 268 269 MODULE_LICENSE("GPL"); 270 MODULE_DESCRIPTION("SHA-224 and SHA-256 Secure Hash Algorithm, SPE optimized"); 271 272 MODULE_ALIAS_CRYPTO("sha224"); 273 MODULE_ALIAS_CRYPTO("sha224-ppc-spe"); 274 MODULE_ALIAS_CRYPTO("sha256"); 275 MODULE_ALIAS_CRYPTO("sha256-ppc-spe"); 276