arch/powerpc/crypto/sha256-spe-glue.c

   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");