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

   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");