1 // SPDX-License-Identifier: GPL-2.0-only
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
10 * Copyright (C) 2008 Intel Corporation
11 * Authors: Austin Zhang <austin_zhang@linux.intel.com>
12 * Kent Liu <kent.liu@intel.com>
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>
21 #include <asm/cpufeatures.h>
22 #include <asm/cpu_device_id.h>
25 #define CHKSUM_BLOCK_SIZE 1
26 #define CHKSUM_DIGEST_SIZE 4
28 #define SCALE_F sizeof(unsigned long)
31 #define REX_PRE "0x48, "
38 * use carryless multiply version of crc32c when buffer
39 * size is >= 512 to account
40 * for fpu state save/restore overhead.
42 #define CRC32C_PCL_BREAKEVEN 512
44 asmlinkage unsigned int crc_pcl(const u8 *buffer, int len,
45 unsigned int crc_init);
46 #endif /* CONFIG_X86_64 */
48 static u32 crc32c_intel_le_hw_byte(u32 crc, unsigned char const *data, size_t length)
52 ".byte 0xf2, 0xf, 0x38, 0xf0, 0xf1"
62 static u32 __pure crc32c_intel_le_hw(u32 crc, unsigned char const *p, size_t len)
64 unsigned int iquotient = len / SCALE_F;
65 unsigned int iremainder = len % SCALE_F;
66 unsigned long *ptmp = (unsigned long *)p;
70 ".byte 0xf2, " REX_PRE "0xf, 0x38, 0xf1, 0xf1;"
78 crc = crc32c_intel_le_hw_byte(crc, (unsigned char *)ptmp,
85 * Setting the seed allows arbitrary accumulators and flexible XOR policy
86 * If your algorithm starts with ~0, then XOR with ~0 before you set
89 static int crc32c_intel_setkey(struct crypto_shash *hash, const u8 *key,
92 u32 *mctx = crypto_shash_ctx(hash);
94 if (keylen != sizeof(u32)) {
95 crypto_shash_set_flags(hash, CRYPTO_TFM_RES_BAD_KEY_LEN);
98 *mctx = le32_to_cpup((__le32 *)key);
102 static int crc32c_intel_init(struct shash_desc *desc)
104 u32 *mctx = crypto_shash_ctx(desc->tfm);
105 u32 *crcp = shash_desc_ctx(desc);
112 static int crc32c_intel_update(struct shash_desc *desc, const u8 *data,
115 u32 *crcp = shash_desc_ctx(desc);
117 *crcp = crc32c_intel_le_hw(*crcp, data, len);
121 static int __crc32c_intel_finup(u32 *crcp, const u8 *data, unsigned int len,
124 *(__le32 *)out = ~cpu_to_le32(crc32c_intel_le_hw(*crcp, data, len));
128 static int crc32c_intel_finup(struct shash_desc *desc, const u8 *data,
129 unsigned int len, u8 *out)
131 return __crc32c_intel_finup(shash_desc_ctx(desc), data, len, out);
134 static int crc32c_intel_final(struct shash_desc *desc, u8 *out)
136 u32 *crcp = shash_desc_ctx(desc);
138 *(__le32 *)out = ~cpu_to_le32p(crcp);
142 static int crc32c_intel_digest(struct shash_desc *desc, const u8 *data,
143 unsigned int len, u8 *out)
145 return __crc32c_intel_finup(crypto_shash_ctx(desc->tfm), data, len,
149 static int crc32c_intel_cra_init(struct crypto_tfm *tfm)
151 u32 *key = crypto_tfm_ctx(tfm);
159 static int crc32c_pcl_intel_update(struct shash_desc *desc, const u8 *data,
162 u32 *crcp = shash_desc_ctx(desc);
165 * use faster PCL version if datasize is large enough to
166 * overcome kernel fpu state save/restore overhead
168 if (len >= CRC32C_PCL_BREAKEVEN && crypto_simd_usable()) {
170 *crcp = crc_pcl(data, len, *crcp);
173 *crcp = crc32c_intel_le_hw(*crcp, data, len);
177 static int __crc32c_pcl_intel_finup(u32 *crcp, const u8 *data, unsigned int len,
180 if (len >= CRC32C_PCL_BREAKEVEN && crypto_simd_usable()) {
182 *(__le32 *)out = ~cpu_to_le32(crc_pcl(data, len, *crcp));
186 ~cpu_to_le32(crc32c_intel_le_hw(*crcp, data, len));
190 static int crc32c_pcl_intel_finup(struct shash_desc *desc, const u8 *data,
191 unsigned int len, u8 *out)
193 return __crc32c_pcl_intel_finup(shash_desc_ctx(desc), data, len, out);
196 static int crc32c_pcl_intel_digest(struct shash_desc *desc, const u8 *data,
197 unsigned int len, u8 *out)
199 return __crc32c_pcl_intel_finup(crypto_shash_ctx(desc->tfm), data, len,
202 #endif /* CONFIG_X86_64 */
204 static struct shash_alg alg = {
205 .setkey = crc32c_intel_setkey,
206 .init = crc32c_intel_init,
207 .update = crc32c_intel_update,
208 .final = crc32c_intel_final,
209 .finup = crc32c_intel_finup,
210 .digest = crc32c_intel_digest,
211 .descsize = sizeof(u32),
212 .digestsize = CHKSUM_DIGEST_SIZE,
214 .cra_name = "crc32c",
215 .cra_driver_name = "crc32c-intel",
217 .cra_flags = CRYPTO_ALG_OPTIONAL_KEY,
218 .cra_blocksize = CHKSUM_BLOCK_SIZE,
219 .cra_ctxsize = sizeof(u32),
220 .cra_module = THIS_MODULE,
221 .cra_init = crc32c_intel_cra_init,
225 static const struct x86_cpu_id crc32c_cpu_id[] = {
226 X86_FEATURE_MATCH(X86_FEATURE_XMM4_2),
229 MODULE_DEVICE_TABLE(x86cpu, crc32c_cpu_id);
231 static int __init crc32c_intel_mod_init(void)
233 if (!x86_match_cpu(crc32c_cpu_id))
236 if (boot_cpu_has(X86_FEATURE_PCLMULQDQ)) {
237 alg.update = crc32c_pcl_intel_update;
238 alg.finup = crc32c_pcl_intel_finup;
239 alg.digest = crc32c_pcl_intel_digest;
242 return crypto_register_shash(&alg);
245 static void __exit crc32c_intel_mod_fini(void)
247 crypto_unregister_shash(&alg);
250 module_init(crc32c_intel_mod_init);
251 module_exit(crc32c_intel_mod_fini);
253 MODULE_AUTHOR("Austin Zhang <austin.zhang@intel.com>, Kent Liu <kent.liu@intel.com>");
254 MODULE_DESCRIPTION("CRC32c (Castagnoli) optimization using Intel Hardware.");
255 MODULE_LICENSE("GPL");
257 MODULE_ALIAS_CRYPTO("crc32c");
258 MODULE_ALIAS_CRYPTO("crc32c-intel");