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| 1 | +/* |
| 2 | + * Using hardware provided CRC32 instruction to accelerate the CRC32 disposal. |
| 3 | + * CRC32C polynomial:0x1EDC6F41(BE)/0x82F63B78(LE) |
| 4 | + * CRC32 is a new instruction in Intel SSE4.2, the reference can be found at: |
| 5 | + * http://www.intel.com/products/processor/manuals/ |
| 6 | + * Intel(R) 64 and IA-32 Architectures Software Developer's Manual |
| 7 | + * Volume 2A: Instruction Set Reference, A-M |
| 8 | + * |
| 9 | + * Copyright (c) 2008 Austin Zhang <[email protected]> |
| 10 | + * Copyright (c) 2008 Kent Liu <[email protected]> |
| 11 | + * |
| 12 | + * This program is free software; you can redistribute it and/or modify it |
| 13 | + * under the terms of the GNU General Public License as published by the Free |
| 14 | + * Software Foundation; either version 2 of the License, or (at your option) |
| 15 | + * any later version. |
| 16 | + * |
| 17 | + */ |
| 18 | +#include <linux/init.h> |
| 19 | +#include <linux/module.h> |
| 20 | +#include <linux/string.h> |
| 21 | +#include <linux/kernel.h> |
| 22 | +#include <crypto/internal/hash.h> |
| 23 | + |
| 24 | +#include <asm/cpufeature.h> |
| 25 | + |
| 26 | +#define CHKSUM_BLOCK_SIZE 1 |
| 27 | +#define CHKSUM_DIGEST_SIZE 4 |
| 28 | + |
| 29 | +#define SCALE_F sizeof(unsigned long) |
| 30 | + |
| 31 | +#ifdef CONFIG_X86_64 |
| 32 | +#define REX_PRE "0x48, " |
| 33 | +#else |
| 34 | +#define REX_PRE |
| 35 | +#endif |
| 36 | + |
| 37 | +static u32 crc32c_intel_le_hw_byte(u32 crc, unsigned char const *data, size_t length) |
| 38 | +{ |
| 39 | + while (length--) { |
| 40 | + __asm__ __volatile__( |
| 41 | + ".byte 0xf2, 0xf, 0x38, 0xf0, 0xf1" |
| 42 | + :"=S"(crc) |
| 43 | + :"0"(crc), "c"(*data) |
| 44 | + ); |
| 45 | + data++; |
| 46 | + } |
| 47 | + |
| 48 | + return crc; |
| 49 | +} |
| 50 | + |
| 51 | +static u32 __pure crc32c_intel_le_hw(u32 crc, unsigned char const *p, size_t len) |
| 52 | +{ |
| 53 | + unsigned int iquotient = len / SCALE_F; |
| 54 | + unsigned int iremainder = len % SCALE_F; |
| 55 | + unsigned long *ptmp = (unsigned long *)p; |
| 56 | + |
| 57 | + while (iquotient--) { |
| 58 | + __asm__ __volatile__( |
| 59 | + ".byte 0xf2, " REX_PRE "0xf, 0x38, 0xf1, 0xf1;" |
| 60 | + :"=S"(crc) |
| 61 | + :"0"(crc), "c"(*ptmp) |
| 62 | + ); |
| 63 | + ptmp++; |
| 64 | + } |
| 65 | + |
| 66 | + if (iremainder) |
| 67 | + crc = crc32c_intel_le_hw_byte(crc, (unsigned char *)ptmp, |
| 68 | + iremainder); |
| 69 | + |
| 70 | + return crc; |
| 71 | +} |
| 72 | + |
| 73 | +/* |
| 74 | + * Setting the seed allows arbitrary accumulators and flexible XOR policy |
| 75 | + * If your algorithm starts with ~0, then XOR with ~0 before you set |
| 76 | + * the seed. |
| 77 | + */ |
| 78 | +static int crc32c_intel_setkey(struct crypto_ahash *hash, const u8 *key, |
| 79 | + unsigned int keylen) |
| 80 | +{ |
| 81 | + u32 *mctx = crypto_ahash_ctx(hash); |
| 82 | + |
| 83 | + if (keylen != sizeof(u32)) { |
| 84 | + crypto_ahash_set_flags(hash, CRYPTO_TFM_RES_BAD_KEY_LEN); |
| 85 | + return -EINVAL; |
| 86 | + } |
| 87 | + *mctx = le32_to_cpup((__le32 *)key); |
| 88 | + return 0; |
| 89 | +} |
| 90 | + |
| 91 | +static int crc32c_intel_init(struct ahash_request *req) |
| 92 | +{ |
| 93 | + u32 *mctx = crypto_ahash_ctx(crypto_ahash_reqtfm(req)); |
| 94 | + u32 *crcp = ahash_request_ctx(req); |
| 95 | + |
| 96 | + *crcp = *mctx; |
| 97 | + |
| 98 | + return 0; |
| 99 | +} |
| 100 | + |
| 101 | +static int crc32c_intel_update(struct ahash_request *req) |
| 102 | +{ |
| 103 | + struct crypto_hash_walk walk; |
| 104 | + u32 *crcp = ahash_request_ctx(req); |
| 105 | + u32 crc = *crcp; |
| 106 | + int nbytes; |
| 107 | + |
| 108 | + for (nbytes = crypto_hash_walk_first(req, &walk); nbytes; |
| 109 | + nbytes = crypto_hash_walk_done(&walk, 0)) |
| 110 | + crc = crc32c_intel_le_hw(crc, walk.data, nbytes); |
| 111 | + |
| 112 | + *crcp = crc; |
| 113 | + return 0; |
| 114 | +} |
| 115 | + |
| 116 | +static int crc32c_intel_final(struct ahash_request *req) |
| 117 | +{ |
| 118 | + u32 *crcp = ahash_request_ctx(req); |
| 119 | + |
| 120 | + *(__le32 *)req->result = ~cpu_to_le32p(crcp); |
| 121 | + return 0; |
| 122 | +} |
| 123 | + |
| 124 | +static int crc32c_intel_digest(struct ahash_request *req) |
| 125 | +{ |
| 126 | + struct crypto_hash_walk walk; |
| 127 | + u32 *mctx = crypto_ahash_ctx(crypto_ahash_reqtfm(req)); |
| 128 | + u32 crc = *mctx; |
| 129 | + int nbytes; |
| 130 | + |
| 131 | + for (nbytes = crypto_hash_walk_first(req, &walk); nbytes; |
| 132 | + nbytes = crypto_hash_walk_done(&walk, 0)) |
| 133 | + crc = crc32c_intel_le_hw(crc, walk.data, nbytes); |
| 134 | + |
| 135 | + *(__le32 *)req->result = ~cpu_to_le32(crc); |
| 136 | + return 0; |
| 137 | +} |
| 138 | + |
| 139 | +static int crc32c_intel_cra_init(struct crypto_tfm *tfm) |
| 140 | +{ |
| 141 | + u32 *key = crypto_tfm_ctx(tfm); |
| 142 | + |
| 143 | + *key = ~0; |
| 144 | + |
| 145 | + tfm->crt_ahash.reqsize = sizeof(u32); |
| 146 | + |
| 147 | + return 0; |
| 148 | +} |
| 149 | + |
| 150 | +static struct crypto_alg alg = { |
| 151 | + .cra_name = "crc32c", |
| 152 | + .cra_driver_name = "crc32c-intel", |
| 153 | + .cra_priority = 200, |
| 154 | + .cra_flags = CRYPTO_ALG_TYPE_AHASH, |
| 155 | + .cra_blocksize = CHKSUM_BLOCK_SIZE, |
| 156 | + .cra_alignmask = 3, |
| 157 | + .cra_ctxsize = sizeof(u32), |
| 158 | + .cra_module = THIS_MODULE, |
| 159 | + .cra_list = LIST_HEAD_INIT(alg.cra_list), |
| 160 | + .cra_init = crc32c_intel_cra_init, |
| 161 | + .cra_type = &crypto_ahash_type, |
| 162 | + .cra_u = { |
| 163 | + .ahash = { |
| 164 | + .digestsize = CHKSUM_DIGEST_SIZE, |
| 165 | + .setkey = crc32c_intel_setkey, |
| 166 | + .init = crc32c_intel_init, |
| 167 | + .update = crc32c_intel_update, |
| 168 | + .final = crc32c_intel_final, |
| 169 | + .digest = crc32c_intel_digest, |
| 170 | + } |
| 171 | + } |
| 172 | +}; |
| 173 | + |
| 174 | + |
| 175 | +static int __init crc32c_intel_mod_init(void) |
| 176 | +{ |
| 177 | + if (cpu_has_xmm4_2) |
| 178 | + return crypto_register_alg(&alg); |
| 179 | + else |
| 180 | + return -ENODEV; |
| 181 | +} |
| 182 | + |
| 183 | +static void __exit crc32c_intel_mod_fini(void) |
| 184 | +{ |
| 185 | + crypto_unregister_alg(&alg); |
| 186 | +} |
| 187 | + |
| 188 | +module_init(crc32c_intel_mod_init); |
| 189 | +module_exit(crc32c_intel_mod_fini); |
| 190 | + |
| 191 | +MODULE_AUTHOR( "Austin Zhang <[email protected]>, Kent Liu <[email protected]>"); |
| 192 | +MODULE_DESCRIPTION("CRC32c (Castagnoli) optimization using Intel Hardware."); |
| 193 | +MODULE_LICENSE("GPL"); |
| 194 | + |
| 195 | +MODULE_ALIAS("crc32c"); |
| 196 | +MODULE_ALIAS("crc32c-intel"); |
| 197 | + |
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