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

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