arch/x86/crypto/crc32c-intel_glue.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Using hardware provided CRC32 instruction to accelerate the CRC32 disposal.
   4  * CRC32C polynomial:0x1EDC6F41(BE)/0x82F63B78(LE)
   5  * CRC32 is a new instruction in Intel SSE4.2, the reference can be found at:
   6  * http://www.intel.com/products/processor/manuals/
   7  * Intel(R) 64 and IA-32 Architectures Software Developer's Manual
   8  * Volume 2A: Instruction Set Reference, A-M
   9  *
  10  * Copyright (C) 2008 Intel Corporation
  11  * Authors: Austin Zhang <[email protected]>
  12  *          Kent Liu <[email protected]>
  13  */
  14 #include <linux/init.h>
  15 #include <linux/module.h>
  16 #include <linux/string.h>
  17 #include <linux/kernel.h>
  18 #include <crypto/internal/hash.h>
  19 #include <crypto/internal/simd.h>
  20
  21 #include <asm/cpufeatures.h>
  22 #include <asm/cpu_device_id.h>
  23 #include <asm/simd.h>
  24
  25 #define CHKSUM_BLOCK_SIZE       1
  26 #define CHKSUM_DIGEST_SIZE      4
  27
  28 #define SCALE_F sizeof(unsigned long)
  29
  30 #ifdef CONFIG_X86_64
  31 #define CRC32_INST "crc32q %1, %q0"
  32 #else
  33 #define CRC32_INST "crc32l %1, %0"
  34 #endif
  35
  36 #ifdef CONFIG_X86_64
  37 /*
  38  * use carryless multiply version of crc32c when buffer
  39  * size is >= 512 to account
  40  * for fpu state save/restore overhead.
  41  */
  42 #define CRC32C_PCL_BREAKEVEN    512
  43
  44 asmlinkage unsigned int crc_pcl(const u8 *buffer, int len,
  45                                 unsigned int crc_init);
  46 #endif /* CONFIG_X86_64 */
  47
  48 static u32 crc32c_intel_le_hw_byte(u32 crc, unsigned char const *data, size_t length)
  49 {
  50         while (length--) {
  51                 asm("crc32b %1, %0"
  52                     : "+r" (crc) : "rm" (*data));
  53                 data++;
  54         }
  55
  56         return crc;
  57 }
  58
  59 static u32 __pure crc32c_intel_le_hw(u32 crc, unsigned char const *p, size_t len)
  60 {
  61         unsigned int iquotient = len / SCALE_F;
  62         unsigned int iremainder = len % SCALE_F;
  63         unsigned long *ptmp = (unsigned long *)p;
  64
  65         while (iquotient--) {
  66                 asm(CRC32_INST
  67                     : "+r" (crc) : "rm" (*ptmp));
  68                 ptmp++;
  69         }
  70
  71         if (iremainder)
  72                 crc = crc32c_intel_le_hw_byte(crc, (unsigned char *)ptmp,
  73                                  iremainder);
  74
  75         return crc;
  76 }
  77
  78 /*
  79  * Setting the seed allows arbitrary accumulators and flexible XOR policy
  80  * If your algorithm starts with ~0, then XOR with ~0 before you set
  81  * the seed.
  82  */
  83 static int crc32c_intel_setkey(struct crypto_shash *hash, const u8 *key,
  84                         unsigned int keylen)
  85 {
  86         u32 *mctx = crypto_shash_ctx(hash);
  87
  88         if (keylen != sizeof(u32))
  89                 return -EINVAL;
  90         *mctx = le32_to_cpup((__le32 *)key);
  91         return 0;
  92 }
  93
  94 static int crc32c_intel_init(struct shash_desc *desc)
  95 {
  96         u32 *mctx = crypto_shash_ctx(desc->tfm);
  97         u32 *crcp = shash_desc_ctx(desc);
  98
  99         *crcp = *mctx;
 100
 101         return 0;
 102 }
 103
 104 static int crc32c_intel_update(struct shash_desc *desc, const u8 *data,
 105                                unsigned int len)
 106 {
 107         u32 *crcp = shash_desc_ctx(desc);
 108
 109         *crcp = crc32c_intel_le_hw(*crcp, data, len);
 110         return 0;
 111 }
 112
 113 static int __crc32c_intel_finup(u32 *crcp, const u8 *data, unsigned int len,
 114                                 u8 *out)
 115 {
 116         *(__le32 *)out = ~cpu_to_le32(crc32c_intel_le_hw(*crcp, data, len));
 117         return 0;
 118 }
 119
 120 static int crc32c_intel_finup(struct shash_desc *desc, const u8 *data,
 121                               unsigned int len, u8 *out)
 122 {
 123         return __crc32c_intel_finup(shash_desc_ctx(desc), data, len, out);
 124 }
 125
 126 static int crc32c_intel_final(struct shash_desc *desc, u8 *out)
 127 {
 128         u32 *crcp = shash_desc_ctx(desc);
 129
 130         *(__le32 *)out = ~cpu_to_le32p(crcp);
 131         return 0;
 132 }
 133
 134 static int crc32c_intel_digest(struct shash_desc *desc, const u8 *data,
 135                                unsigned int len, u8 *out)
 136 {
 137         return __crc32c_intel_finup(crypto_shash_ctx(desc->tfm), data, len,
 138                                     out);
 139 }
 140
 141 static int crc32c_intel_cra_init(struct crypto_tfm *tfm)
 142 {
 143         u32 *key = crypto_tfm_ctx(tfm);
 144
 145         *key = ~0;
 146
 147         return 0;
 148 }
 149
 150 #ifdef CONFIG_X86_64
 151 static int crc32c_pcl_intel_update(struct shash_desc *desc, const u8 *data,
 152                                unsigned int len)
 153 {
 154         u32 *crcp = shash_desc_ctx(desc);
 155
 156         /*
 157          * use faster PCL version if datasize is large enough to
 158          * overcome kernel fpu state save/restore overhead
 159          */
 160         if (len >= CRC32C_PCL_BREAKEVEN && crypto_simd_usable()) {
 161                 kernel_fpu_begin();
 162                 *crcp = crc_pcl(data, len, *crcp);
 163                 kernel_fpu_end();
 164         } else
 165                 *crcp = crc32c_intel_le_hw(*crcp, data, len);
 166         return 0;
 167 }
 168
 169 static int __crc32c_pcl_intel_finup(u32 *crcp, const u8 *data, unsigned int len,
 170                                 u8 *out)
 171 {
 172         if (len >= CRC32C_PCL_BREAKEVEN && crypto_simd_usable()) {
 173                 kernel_fpu_begin();
 174                 *(__le32 *)out = ~cpu_to_le32(crc_pcl(data, len, *crcp));
 175                 kernel_fpu_end();
 176         } else
 177                 *(__le32 *)out =
 178                         ~cpu_to_le32(crc32c_intel_le_hw(*crcp, data, len));
 179         return 0;
 180 }
 181
 182 static int crc32c_pcl_intel_finup(struct shash_desc *desc, const u8 *data,
 183                               unsigned int len, u8 *out)
 184 {
 185         return __crc32c_pcl_intel_finup(shash_desc_ctx(desc), data, len, out);
 186 }
 187
 188 static int crc32c_pcl_intel_digest(struct shash_desc *desc, const u8 *data,
 189                                unsigned int len, u8 *out)
 190 {
 191         return __crc32c_pcl_intel_finup(crypto_shash_ctx(desc->tfm), data, len,
 192                                     out);
 193 }
 194 #endif /* CONFIG_X86_64 */
 195
 196 static struct shash_alg alg = {
 197         .setkey                 =       crc32c_intel_setkey,
 198         .init                   =       crc32c_intel_init,
 199         .update                 =       crc32c_intel_update,
 200         .final                  =       crc32c_intel_final,
 201         .finup                  =       crc32c_intel_finup,
 202         .digest                 =       crc32c_intel_digest,
 203         .descsize               =       sizeof(u32),
 204         .digestsize             =       CHKSUM_DIGEST_SIZE,
 205         .base                   =       {
 206                 .cra_name               =       "crc32c",
 207                 .cra_driver_name        =       "crc32c-intel",
 208                 .cra_priority           =       200,
 209                 .cra_flags              =       CRYPTO_ALG_OPTIONAL_KEY,
 210                 .cra_blocksize          =       CHKSUM_BLOCK_SIZE,
 211                 .cra_ctxsize            =       sizeof(u32),
 212                 .cra_module             =       THIS_MODULE,
 213                 .cra_init               =       crc32c_intel_cra_init,
 214         }
 215 };
 216
 217 static const struct x86_cpu_id crc32c_cpu_id[] = {
 218         X86_MATCH_FEATURE(X86_FEATURE_XMM4_2, NULL),
 219         {}
 220 };
 221 MODULE_DEVICE_TABLE(x86cpu, crc32c_cpu_id);
 222
 223 static int __init crc32c_intel_mod_init(void)
 224 {
 225         if (!x86_match_cpu(crc32c_cpu_id))
 226                 return -ENODEV;
 227 #ifdef CONFIG_X86_64
 228         if (boot_cpu_has(X86_FEATURE_PCLMULQDQ)) {
 229                 alg.update = crc32c_pcl_intel_update;
 230                 alg.finup = crc32c_pcl_intel_finup;
 231                 alg.digest = crc32c_pcl_intel_digest;
 232         }
 233 #endif
 234         return crypto_register_shash(&alg);
 235 }
 236
 237 static void __exit crc32c_intel_mod_fini(void)
 238 {
 239         crypto_unregister_shash(&alg);
 240 }
 241
 242 module_init(crc32c_intel_mod_init);
 243 module_exit(crc32c_intel_mod_fini);
 244
 245 MODULE_AUTHOR("Austin Zhang <[email protected]>, Kent Liu <[email protected]>");
 246 MODULE_DESCRIPTION("CRC32c (Castagnoli) optimization using Intel Hardware.");
 247 MODULE_LICENSE("GPL");
 248
 249 MODULE_ALIAS_CRYPTO("crc32c");
 250 MODULE_ALIAS_CRYPTO("crc32c-intel");