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

DEFINITIONS

1. spe_begin
2. spe_end
3. ppc_sha1_clear_context
4. ppc_spe_sha1_init
5. ppc_spe_sha1_update
6. ppc_spe_sha1_final
7. ppc_spe_sha1_export
8. ppc_spe_sha1_import
9. ppc_spe_sha1_mod_init
10. ppc_spe_sha1_mod_fini

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Glue code for SHA-1 implementation for SPE instructions (PPC)
   4  *
   5  * Based on generic implementation.
   6  *
   7  * Copyright (c) 2015 Markus Stockhausen <stockhausen@collogia.de>
   8  */
   9 
  10 #include <crypto/internal/hash.h>
  11 #include <linux/init.h>
  12 #include <linux/module.h>
  13 #include <linux/mm.h>
  14 #include <linux/cryptohash.h>
  15 #include <linux/types.h>
  16 #include <crypto/sha.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(). SHA1 takes ~1000
  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 2KB 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 2048
  32 
  33 extern void ppc_spe_sha1_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_sha1_clear_context(struct sha1_state *sctx)
  50 {
  51         int count = sizeof(struct sha1_state) >> 2;
  52         u32 *ptr = (u32 *)sctx;
  53 
  54         /* make sure we can clear the fast way */
  55         BUILD_BUG_ON(sizeof(struct sha1_state) % 4);
  56         do { *ptr++ = 0; } while (--count);
  57 }
  58 
  59 static int ppc_spe_sha1_init(struct shash_desc *desc)
  60 {
  61         struct sha1_state *sctx = shash_desc_ctx(desc);
  62 
  63         sctx->state[0] = SHA1_H0;
  64         sctx->state[1] = SHA1_H1;
  65         sctx->state[2] = SHA1_H2;
  66         sctx->state[3] = SHA1_H3;
  67         sctx->state[4] = SHA1_H4;
  68         sctx->count = 0;
  69 
  70         return 0;
  71 }
  72 
  73 static int ppc_spe_sha1_update(struct shash_desc *desc, const u8 *data,
  74                         unsigned int len)
  75 {
  76         struct sha1_state *sctx = shash_desc_ctx(desc);
  77         const unsigned int offset = sctx->count & 0x3f;
  78         const unsigned int avail = 64 - offset;
  79         unsigned int bytes;
  80         const u8 *src = data;
  81 
  82         if (avail > len) {
  83                 sctx->count += len;
  84                 memcpy((char *)sctx->buffer + offset, src, len);
  85                 return 0;
  86         }
  87 
  88         sctx->count += len;
  89 
  90         if (offset) {
  91                 memcpy((char *)sctx->buffer + offset, src, avail);
  92 
  93                 spe_begin();
  94                 ppc_spe_sha1_transform(sctx->state, (const u8 *)sctx->buffer, 1);
  95                 spe_end();
  96 
  97                 len -= avail;
  98                 src += avail;
  99         }
 100 
 101         while (len > 63) {
 102                 bytes = (len > MAX_BYTES) ? MAX_BYTES : len;
 103                 bytes = bytes & ~0x3f;
 104 
 105                 spe_begin();
 106                 ppc_spe_sha1_transform(sctx->state, src, bytes >> 6);
 107                 spe_end();
 108 
 109                 src += bytes;
 110                 len -= bytes;
 111         };
 112 
 113         memcpy((char *)sctx->buffer, src, len);
 114         return 0;
 115 }
 116 
 117 static int ppc_spe_sha1_final(struct shash_desc *desc, u8 *out)
 118 {
 119         struct sha1_state *sctx = shash_desc_ctx(desc);
 120         const unsigned int offset = sctx->count & 0x3f;
 121         char *p = (char *)sctx->buffer + offset;
 122         int padlen;
 123         __be64 *pbits = (__be64 *)(((char *)&sctx->buffer) + 56);
 124         __be32 *dst = (__be32 *)out;
 125 
 126         padlen = 55 - offset;
 127         *p++ = 0x80;
 128 
 129         spe_begin();
 130 
 131         if (padlen < 0) {
 132                 memset(p, 0x00, padlen + sizeof (u64));
 133                 ppc_spe_sha1_transform(sctx->state, sctx->buffer, 1);
 134                 p = (char *)sctx->buffer;
 135                 padlen = 56;
 136         }
 137 
 138         memset(p, 0, padlen);
 139         *pbits = cpu_to_be64(sctx->count << 3);
 140         ppc_spe_sha1_transform(sctx->state, sctx->buffer, 1);
 141 
 142         spe_end();
 143 
 144         dst[0] = cpu_to_be32(sctx->state[0]);
 145         dst[1] = cpu_to_be32(sctx->state[1]);
 146         dst[2] = cpu_to_be32(sctx->state[2]);
 147         dst[3] = cpu_to_be32(sctx->state[3]);
 148         dst[4] = cpu_to_be32(sctx->state[4]);
 149 
 150         ppc_sha1_clear_context(sctx);
 151         return 0;
 152 }
 153 
 154 static int ppc_spe_sha1_export(struct shash_desc *desc, void *out)
 155 {
 156         struct sha1_state *sctx = shash_desc_ctx(desc);
 157 
 158         memcpy(out, sctx, sizeof(*sctx));
 159         return 0;
 160 }
 161 
 162 static int ppc_spe_sha1_import(struct shash_desc *desc, const void *in)
 163 {
 164         struct sha1_state *sctx = shash_desc_ctx(desc);
 165 
 166         memcpy(sctx, in, sizeof(*sctx));
 167         return 0;
 168 }
 169 
 170 static struct shash_alg alg = {
 171         .digestsize     =       SHA1_DIGEST_SIZE,
 172         .init           =       ppc_spe_sha1_init,
 173         .update         =       ppc_spe_sha1_update,
 174         .final          =       ppc_spe_sha1_final,
 175         .export         =       ppc_spe_sha1_export,
 176         .import         =       ppc_spe_sha1_import,
 177         .descsize       =       sizeof(struct sha1_state),
 178         .statesize      =       sizeof(struct sha1_state),
 179         .base           =       {
 180                 .cra_name       =       "sha1",
 181                 .cra_driver_name=       "sha1-ppc-spe",
 182                 .cra_priority   =       300,
 183                 .cra_blocksize  =       SHA1_BLOCK_SIZE,
 184                 .cra_module     =       THIS_MODULE,
 185         }
 186 };
 187 
 188 static int __init ppc_spe_sha1_mod_init(void)
 189 {
 190         return crypto_register_shash(&alg);
 191 }
 192 
 193 static void __exit ppc_spe_sha1_mod_fini(void)
 194 {
 195         crypto_unregister_shash(&alg);
 196 }
 197 
 198 module_init(ppc_spe_sha1_mod_init);
 199 module_exit(ppc_spe_sha1_mod_fini);
 200 
 201 MODULE_LICENSE("GPL");
 202 MODULE_DESCRIPTION("SHA1 Secure Hash Algorithm, SPE optimized");
 203 
 204 MODULE_ALIAS_CRYPTO("sha1");
 205 MODULE_ALIAS_CRYPTO("sha1-ppc-spe");