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

DEFINITIONS

1. spe_begin
2. spe_end
3. ppc_sha256_clear_context
4. ppc_spe_sha256_init
5. ppc_spe_sha224_init
6. ppc_spe_sha256_update
7. ppc_spe_sha256_final
8. ppc_spe_sha224_final
9. ppc_spe_sha256_export
10. ppc_spe_sha256_import
11. ppc_spe_sha256_mod_init
12. ppc_spe_sha256_mod_fini

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