arch/powerpc/crypto/sha1-spe-glue.c

   1 /*
   2  * Glue code for SHA-1 implementation for SPE instructions (PPC)
   3  *
   4  * Based on generic implementation.
   5  *
   6  * Copyright (c) 2015 Markus Stockhausen <stockhausen@collogia.de>
   7  *
   8  * This program is free software; you can redistribute it and/or modify it
   9  * under the terms of the GNU General Public License as published by the Free
  10  * Software Foundation; either version 2 of the License, or (at your option)
  11  * any later version.
  12  *
  13  */
  14
  15 #include <crypto/internal/hash.h>
  16 #include <linux/init.h>
  17 #include <linux/module.h>
  18 #include <linux/mm.h>
  19 #include <linux/cryptohash.h>
  20 #include <linux/types.h>
  21 #include <crypto/sha.h>
  22 #include <asm/byteorder.h>
  23 #include <asm/switch_to.h>
  24 #include <linux/hardirq.h>
  25
  26 /*
  27  * MAX_BYTES defines the number of bytes that are allowed to be processed
  28  * between preempt_disable() and preempt_enable(). SHA1 takes ~1000
  29  * operations per 64 bytes. e500 cores can issue two arithmetic instructions
  30  * per clock cycle using one 32/64 bit unit (SU1) and one 32 bit unit (SU2).
  31  * Thus 2KB of input data will need an estimated maximum of 18,000 cycles.
  32  * Headroom for cache misses included. Even with the low end model clocked
  33  * at 667 MHz this equals to a critical time window of less than 27us.
  34  *
  35  */
  36 #define MAX_BYTES 2048
  37
  38 extern void ppc_spe_sha1_transform(u32 *state, const u8 *src, u32 blocks);
  39
  40 static void spe_begin(void)
  41 {
  42         /* We just start SPE operations and will save SPE registers later. */
  43         preempt_disable();
  44         enable_kernel_spe();
  45 }
  46
  47 static void spe_end(void)
  48 {
  49         disable_kernel_spe();
  50         /* reenable preemption */
  51         preempt_enable();
  52 }
  53
  54 static inline void ppc_sha1_clear_context(struct sha1_state *sctx)
  55 {
  56         int count = sizeof(struct sha1_state) >> 2;
  57         u32 *ptr = (u32 *)sctx;
  58
  59         /* make sure we can clear the fast way */
  60         BUILD_BUG_ON(sizeof(struct sha1_state) % 4);
  61         do { *ptr++ = 0; } while (--count);
  62 }
  63
  64 static int ppc_spe_sha1_init(struct shash_desc *desc)
  65 {
  66         struct sha1_state *sctx = shash_desc_ctx(desc);
  67
  68         sctx->state[0] = SHA1_H0;
  69         sctx->state[1] = SHA1_H1;
  70         sctx->state[2] = SHA1_H2;
  71         sctx->state[3] = SHA1_H3;
  72         sctx->state[4] = SHA1_H4;
  73         sctx->count = 0;
  74
  75         return 0;
  76 }
  77
  78 static int ppc_spe_sha1_update(struct shash_desc *desc, const u8 *data,
  79                         unsigned int len)
  80 {
  81         struct sha1_state *sctx = shash_desc_ctx(desc);
  82         const unsigned int offset = sctx->count & 0x3f;
  83         const unsigned int avail = 64 - offset;
  84         unsigned int bytes;
  85         const u8 *src = data;
  86
  87         if (avail > len) {
  88                 sctx->count += len;
  89                 memcpy((char *)sctx->buffer + offset, src, len);
  90                 return 0;
  91         }
  92
  93         sctx->count += len;
  94
  95         if (offset) {
  96                 memcpy((char *)sctx->buffer + offset, src, avail);
  97
  98                 spe_begin();
  99                 ppc_spe_sha1_transform(sctx->state, (const u8 *)sctx->buffer, 1);
 100                 spe_end();
 101
 102                 len -= avail;
 103                 src += avail;
 104         }
 105
 106         while (len > 63) {
 107                 bytes = (len > MAX_BYTES) ? MAX_BYTES : len;
 108                 bytes = bytes & ~0x3f;
 109
 110                 spe_begin();
 111                 ppc_spe_sha1_transform(sctx->state, src, bytes >> 6);
 112                 spe_end();
 113
 114                 src += bytes;
 115                 len -= bytes;
 116         };
 117
 118         memcpy((char *)sctx->buffer, src, len);
 119         return 0;
 120 }
 121
 122 static int ppc_spe_sha1_final(struct shash_desc *desc, u8 *out)
 123 {
 124         struct sha1_state *sctx = shash_desc_ctx(desc);
 125         const unsigned int offset = sctx->count & 0x3f;
 126         char *p = (char *)sctx->buffer + offset;
 127         int padlen;
 128         __be64 *pbits = (__be64 *)(((char *)&sctx->buffer) + 56);
 129         __be32 *dst = (__be32 *)out;
 130
 131         padlen = 55 - offset;
 132         *p++ = 0x80;
 133
 134         spe_begin();
 135
 136         if (padlen < 0) {
 137                 memset(p, 0x00, padlen + sizeof (u64));
 138                 ppc_spe_sha1_transform(sctx->state, sctx->buffer, 1);
 139                 p = (char *)sctx->buffer;
 140                 padlen = 56;
 141         }
 142
 143         memset(p, 0, padlen);
 144         *pbits = cpu_to_be64(sctx->count << 3);
 145         ppc_spe_sha1_transform(sctx->state, sctx->buffer, 1);
 146
 147         spe_end();
 148
 149         dst[0] = cpu_to_be32(sctx->state[0]);
 150         dst[1] = cpu_to_be32(sctx->state[1]);
 151         dst[2] = cpu_to_be32(sctx->state[2]);
 152         dst[3] = cpu_to_be32(sctx->state[3]);
 153         dst[4] = cpu_to_be32(sctx->state[4]);
 154
 155         ppc_sha1_clear_context(sctx);
 156         return 0;
 157 }
 158
 159 static int ppc_spe_sha1_export(struct shash_desc *desc, void *out)
 160 {
 161         struct sha1_state *sctx = shash_desc_ctx(desc);
 162
 163         memcpy(out, sctx, sizeof(*sctx));
 164         return 0;
 165 }
 166
 167 static int ppc_spe_sha1_import(struct shash_desc *desc, const void *in)
 168 {
 169         struct sha1_state *sctx = shash_desc_ctx(desc);
 170
 171         memcpy(sctx, in, sizeof(*sctx));
 172         return 0;
 173 }
 174
 175 static struct shash_alg alg = {
 176         .digestsize     =       SHA1_DIGEST_SIZE,
 177         .init           =       ppc_spe_sha1_init,
 178         .update         =       ppc_spe_sha1_update,
 179         .final          =       ppc_spe_sha1_final,
 180         .export         =       ppc_spe_sha1_export,
 181         .import         =       ppc_spe_sha1_import,
 182         .descsize       =       sizeof(struct sha1_state),
 183         .statesize      =       sizeof(struct sha1_state),
 184         .base           =       {
 185                 .cra_name       =       "sha1",
 186                 .cra_driver_name=       "sha1-ppc-spe",
 187                 .cra_priority   =       300,
 188                 .cra_flags      =       CRYPTO_ALG_TYPE_SHASH,
 189                 .cra_blocksize  =       SHA1_BLOCK_SIZE,
 190                 .cra_module     =       THIS_MODULE,
 191         }
 192 };
 193
 194 static int __init ppc_spe_sha1_mod_init(void)
 195 {
 196         return crypto_register_shash(&alg);
 197 }
 198
 199 static void __exit ppc_spe_sha1_mod_fini(void)
 200 {
 201         crypto_unregister_shash(&alg);
 202 }
 203
 204 module_init(ppc_spe_sha1_mod_init);
 205 module_exit(ppc_spe_sha1_mod_fini);
 206
 207 MODULE_LICENSE("GPL");
 208 MODULE_DESCRIPTION("SHA1 Secure Hash Algorithm, SPE optimized");
 209
 210 MODULE_ALIAS_CRYPTO("sha1");
 211 MODULE_ALIAS_CRYPTO("sha1-ppc-spe");