1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Glue code for SHA-256 implementation for SPE instructions (PPC) 4 * 5 * Based on generic implementation. The assembler module takes care 6 * about the SPE registers so it can run from interrupt context. 7 * 8 * Copyright (c) 2015 Markus Stockhausen <stockhausen@collogia.de> 9 */ 10 11 #include <crypto/internal/hash.h> 12 #include <linux/init.h> 13 #include <linux/module.h> 14 #include <linux/mm.h> 15 #include <linux/types.h> 16 #include <crypto/sha2.h> 17 #include <asm/byteorder.h> 18 #include <asm/switch_to.h> 19 #include <linux/hardirq.h> 20 21 /* 22 * MAX_BYTES defines the number of bytes that are allowed to be processed 23 * between preempt_disable() and preempt_enable(). SHA256 takes ~2,000 24 * operations per 64 bytes. e500 cores can issue two arithmetic instructions 25 * per clock cycle using one 32/64 bit unit (SU1) and one 32 bit unit (SU2). 26 * Thus 1KB of input data will need an estimated maximum of 18,000 cycles. 27 * Headroom for cache misses included. Even with the low end model clocked 28 * at 667 MHz this equals to a critical time window of less than 27us. 29 * 30 */ 31 #define MAX_BYTES 1024 32 33 extern void ppc_spe_sha256_transform(u32 *state, const u8 *src, u32 blocks); 34 35 static void spe_begin(void) 36 { 37 /* We just start SPE operations and will save SPE registers later. */ 38 preempt_disable(); 39 enable_kernel_spe(); 40 } 41 42 static void spe_end(void) 43 { 44 disable_kernel_spe(); 45 /* reenable preemption */ 46 preempt_enable(); 47 } 48 49 static inline void ppc_sha256_clear_context(struct sha256_state *sctx) 50 { 51 int count = sizeof(struct sha256_state) >> 2; 52 u32 *ptr = (u32 *)sctx; 53 54 /* make sure we can clear the fast way */ 55 BUILD_BUG_ON(sizeof(struct sha256_state) % 4); 56 do { *ptr++ = 0; } while (--count); 57 } 58 59 static int ppc_spe_sha256_init(struct shash_desc *desc) 60 { 61 struct sha256_state *sctx = shash_desc_ctx(desc); 62 63 sctx->state[0] = SHA256_H0; 64 sctx->state[1] = SHA256_H1; 65 sctx->state[2] = SHA256_H2; 66 sctx->state[3] = SHA256_H3; 67 sctx->state[4] = SHA256_H4; 68 sctx->state[5] = SHA256_H5; 69 sctx->state[6] = SHA256_H6; 70 sctx->state[7] = SHA256_H7; 71 sctx->count = 0; 72 73 return 0; 74 } 75 76 static int ppc_spe_sha224_init(struct shash_desc *desc) 77 { 78 struct sha256_state *sctx = shash_desc_ctx(desc); 79 80 sctx->state[0] = SHA224_H0; 81 sctx->state[1] = SHA224_H1; 82 sctx->state[2] = SHA224_H2; 83 sctx->state[3] = SHA224_H3; 84 sctx->state[4] = SHA224_H4; 85 sctx->state[5] = SHA224_H5; 86 sctx->state[6] = SHA224_H6; 87 sctx->state[7] = SHA224_H7; 88 sctx->count = 0; 89 90 return 0; 91 } 92 93 static int ppc_spe_sha256_update(struct shash_desc *desc, const u8 *data, 94 unsigned int len) 95 { 96 struct sha256_state *sctx = shash_desc_ctx(desc); 97 const unsigned int offset = sctx->count & 0x3f; 98 const unsigned int avail = 64 - offset; 99 unsigned int bytes; 100 const u8 *src = data; 101 102 if (avail > len) { 103 sctx->count += len; 104 memcpy((char *)sctx->buf + offset, src, len); 105 return 0; 106 } 107 108 sctx->count += len; 109 110 if (offset) { 111 memcpy((char *)sctx->buf + offset, src, avail); 112 113 spe_begin(); 114 ppc_spe_sha256_transform(sctx->state, (const u8 *)sctx->buf, 1); 115 spe_end(); 116 117 len -= avail; 118 src += avail; 119 } 120 121 while (len > 63) { 122 /* cut input data into smaller blocks */ 123 bytes = (len > MAX_BYTES) ? MAX_BYTES : len; 124 bytes = bytes & ~0x3f; 125 126 spe_begin(); 127 ppc_spe_sha256_transform(sctx->state, src, bytes >> 6); 128 spe_end(); 129 130 src += bytes; 131 len -= bytes; 132 } 133 134 memcpy((char *)sctx->buf, src, len); 135 return 0; 136 } 137 138 static int ppc_spe_sha256_final(struct shash_desc *desc, u8 *out) 139 { 140 struct sha256_state *sctx = shash_desc_ctx(desc); 141 const unsigned int offset = sctx->count & 0x3f; 142 char *p = (char *)sctx->buf + offset; 143 int padlen; 144 __be64 *pbits = (__be64 *)(((char *)&sctx->buf) + 56); 145 __be32 *dst = (__be32 *)out; 146 147 padlen = 55 - offset; 148 *p++ = 0x80; 149 150 spe_begin(); 151 152 if (padlen < 0) { 153 memset(p, 0x00, padlen + sizeof (u64)); 154 ppc_spe_sha256_transform(sctx->state, sctx->buf, 1); 155 p = (char *)sctx->buf; 156 padlen = 56; 157 } 158 159 memset(p, 0, padlen); 160 *pbits = cpu_to_be64(sctx->count << 3); 161 ppc_spe_sha256_transform(sctx->state, sctx->buf, 1); 162 163 spe_end(); 164 165 dst[0] = cpu_to_be32(sctx->state[0]); 166 dst[1] = cpu_to_be32(sctx->state[1]); 167 dst[2] = cpu_to_be32(sctx->state[2]); 168 dst[3] = cpu_to_be32(sctx->state[3]); 169 dst[4] = cpu_to_be32(sctx->state[4]); 170 dst[5] = cpu_to_be32(sctx->state[5]); 171 dst[6] = cpu_to_be32(sctx->state[6]); 172 dst[7] = cpu_to_be32(sctx->state[7]); 173 174 ppc_sha256_clear_context(sctx); 175 return 0; 176 } 177 178 static int ppc_spe_sha224_final(struct shash_desc *desc, u8 *out) 179 { 180 __be32 D[SHA256_DIGEST_SIZE >> 2]; 181 __be32 *dst = (__be32 *)out; 182 183 ppc_spe_sha256_final(desc, (u8 *)D); 184 185 /* avoid bytewise memcpy */ 186 dst[0] = D[0]; 187 dst[1] = D[1]; 188 dst[2] = D[2]; 189 dst[3] = D[3]; 190 dst[4] = D[4]; 191 dst[5] = D[5]; 192 dst[6] = D[6]; 193 194 /* clear sensitive data */ 195 memzero_explicit(D, SHA256_DIGEST_SIZE); 196 return 0; 197 } 198 199 static int ppc_spe_sha256_export(struct shash_desc *desc, void *out) 200 { 201 struct sha256_state *sctx = shash_desc_ctx(desc); 202 203 memcpy(out, sctx, sizeof(*sctx)); 204 return 0; 205 } 206 207 static int ppc_spe_sha256_import(struct shash_desc *desc, const void *in) 208 { 209 struct sha256_state *sctx = shash_desc_ctx(desc); 210 211 memcpy(sctx, in, sizeof(*sctx)); 212 return 0; 213 } 214 215 static struct shash_alg algs[2] = { { 216 .digestsize = SHA256_DIGEST_SIZE, 217 .init = ppc_spe_sha256_init, 218 .update = ppc_spe_sha256_update, 219 .final = ppc_spe_sha256_final, 220 .export = ppc_spe_sha256_export, 221 .import = ppc_spe_sha256_import, 222 .descsize = sizeof(struct sha256_state), 223 .statesize = sizeof(struct sha256_state), 224 .base = { 225 .cra_name = "sha256", 226 .cra_driver_name= "sha256-ppc-spe", 227 .cra_priority = 300, 228 .cra_blocksize = SHA256_BLOCK_SIZE, 229 .cra_module = THIS_MODULE, 230 } 231 }, { 232 .digestsize = SHA224_DIGEST_SIZE, 233 .init = ppc_spe_sha224_init, 234 .update = ppc_spe_sha256_update, 235 .final = ppc_spe_sha224_final, 236 .export = ppc_spe_sha256_export, 237 .import = ppc_spe_sha256_import, 238 .descsize = sizeof(struct sha256_state), 239 .statesize = sizeof(struct sha256_state), 240 .base = { 241 .cra_name = "sha224", 242 .cra_driver_name= "sha224-ppc-spe", 243 .cra_priority = 300, 244 .cra_blocksize = SHA224_BLOCK_SIZE, 245 .cra_module = THIS_MODULE, 246 } 247 } }; 248 249 static int __init ppc_spe_sha256_mod_init(void) 250 { 251 return crypto_register_shashes(algs, ARRAY_SIZE(algs)); 252 } 253 254 static void __exit ppc_spe_sha256_mod_fini(void) 255 { 256 crypto_unregister_shashes(algs, ARRAY_SIZE(algs)); 257 } 258 259 module_init(ppc_spe_sha256_mod_init); 260 module_exit(ppc_spe_sha256_mod_fini); 261 262 MODULE_LICENSE("GPL"); 263 MODULE_DESCRIPTION("SHA-224 and SHA-256 Secure Hash Algorithm, SPE optimized"); 264 265 MODULE_ALIAS_CRYPTO("sha224"); 266 MODULE_ALIAS_CRYPTO("sha224-ppc-spe"); 267 MODULE_ALIAS_CRYPTO("sha256"); 268 MODULE_ALIAS_CRYPTO("sha256-ppc-spe"); 269