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 <austin_zhang@linux.intel.com>
12 * Kent Liu <kent.liu@intel.com>
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 REX_PRE "0x48, "
32 #else
33 #define REX_PRE
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
crc32c_intel_le_hw_byte(u32 crc,unsigned char const * data,size_t length)48 static u32 crc32c_intel_le_hw_byte(u32 crc, unsigned char const *data, size_t length)
49 {
50 while (length--) {
51 __asm__ __volatile__(
52 ".byte 0xf2, 0xf, 0x38, 0xf0, 0xf1"
53 :"=S"(crc)
54 :"0"(crc), "c"(*data)
55 );
56 data++;
57 }
58
59 return crc;
60 }
61
crc32c_intel_le_hw(u32 crc,unsigned char const * p,size_t len)62 static u32 __pure crc32c_intel_le_hw(u32 crc, unsigned char const *p, size_t len)
63 {
64 unsigned int iquotient = len / SCALE_F;
65 unsigned int iremainder = len % SCALE_F;
66 unsigned long *ptmp = (unsigned long *)p;
67
68 while (iquotient--) {
69 __asm__ __volatile__(
70 ".byte 0xf2, " REX_PRE "0xf, 0x38, 0xf1, 0xf1;"
71 :"=S"(crc)
72 :"0"(crc), "c"(*ptmp)
73 );
74 ptmp++;
75 }
76
77 if (iremainder)
78 crc = crc32c_intel_le_hw_byte(crc, (unsigned char *)ptmp,
79 iremainder);
80
81 return crc;
82 }
83
84 /*
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
87 * the seed.
88 */
crc32c_intel_setkey(struct crypto_shash * hash,const u8 * key,unsigned int keylen)89 static int crc32c_intel_setkey(struct crypto_shash *hash, const u8 *key,
90 unsigned int keylen)
91 {
92 u32 *mctx = crypto_shash_ctx(hash);
93
94 if (keylen != sizeof(u32)) {
95 crypto_shash_set_flags(hash, CRYPTO_TFM_RES_BAD_KEY_LEN);
96 return -EINVAL;
97 }
98 *mctx = le32_to_cpup((__le32 *)key);
99 return 0;
100 }
101
crc32c_intel_init(struct shash_desc * desc)102 static int crc32c_intel_init(struct shash_desc *desc)
103 {
104 u32 *mctx = crypto_shash_ctx(desc->tfm);
105 u32 *crcp = shash_desc_ctx(desc);
106
107 *crcp = *mctx;
108
109 return 0;
110 }
111
crc32c_intel_update(struct shash_desc * desc,const u8 * data,unsigned int len)112 static int crc32c_intel_update(struct shash_desc *desc, const u8 *data,
113 unsigned int len)
114 {
115 u32 *crcp = shash_desc_ctx(desc);
116
117 *crcp = crc32c_intel_le_hw(*crcp, data, len);
118 return 0;
119 }
120
__crc32c_intel_finup(u32 * crcp,const u8 * data,unsigned int len,u8 * out)121 static int __crc32c_intel_finup(u32 *crcp, const u8 *data, unsigned int len,
122 u8 *out)
123 {
124 *(__le32 *)out = ~cpu_to_le32(crc32c_intel_le_hw(*crcp, data, len));
125 return 0;
126 }
127
crc32c_intel_finup(struct shash_desc * desc,const u8 * data,unsigned int len,u8 * out)128 static int crc32c_intel_finup(struct shash_desc *desc, const u8 *data,
129 unsigned int len, u8 *out)
130 {
131 return __crc32c_intel_finup(shash_desc_ctx(desc), data, len, out);
132 }
133
crc32c_intel_final(struct shash_desc * desc,u8 * out)134 static int crc32c_intel_final(struct shash_desc *desc, u8 *out)
135 {
136 u32 *crcp = shash_desc_ctx(desc);
137
138 *(__le32 *)out = ~cpu_to_le32p(crcp);
139 return 0;
140 }
141
crc32c_intel_digest(struct shash_desc * desc,const u8 * data,unsigned int len,u8 * out)142 static int crc32c_intel_digest(struct shash_desc *desc, const u8 *data,
143 unsigned int len, u8 *out)
144 {
145 return __crc32c_intel_finup(crypto_shash_ctx(desc->tfm), data, len,
146 out);
147 }
148
crc32c_intel_cra_init(struct crypto_tfm * tfm)149 static int crc32c_intel_cra_init(struct crypto_tfm *tfm)
150 {
151 u32 *key = crypto_tfm_ctx(tfm);
152
153 *key = ~0;
154
155 return 0;
156 }
157
158 #ifdef CONFIG_X86_64
crc32c_pcl_intel_update(struct shash_desc * desc,const u8 * data,unsigned int len)159 static int crc32c_pcl_intel_update(struct shash_desc *desc, const u8 *data,
160 unsigned int len)
161 {
162 u32 *crcp = shash_desc_ctx(desc);
163
164 /*
165 * use faster PCL version if datasize is large enough to
166 * overcome kernel fpu state save/restore overhead
167 */
168 if (len >= CRC32C_PCL_BREAKEVEN && crypto_simd_usable()) {
169 kernel_fpu_begin();
170 *crcp = crc_pcl(data, len, *crcp);
171 kernel_fpu_end();
172 } else
173 *crcp = crc32c_intel_le_hw(*crcp, data, len);
174 return 0;
175 }
176
__crc32c_pcl_intel_finup(u32 * crcp,const u8 * data,unsigned int len,u8 * out)177 static int __crc32c_pcl_intel_finup(u32 *crcp, const u8 *data, unsigned int len,
178 u8 *out)
179 {
180 if (len >= CRC32C_PCL_BREAKEVEN && crypto_simd_usable()) {
181 kernel_fpu_begin();
182 *(__le32 *)out = ~cpu_to_le32(crc_pcl(data, len, *crcp));
183 kernel_fpu_end();
184 } else
185 *(__le32 *)out =
186 ~cpu_to_le32(crc32c_intel_le_hw(*crcp, data, len));
187 return 0;
188 }
189
crc32c_pcl_intel_finup(struct shash_desc * desc,const u8 * data,unsigned int len,u8 * out)190 static int crc32c_pcl_intel_finup(struct shash_desc *desc, const u8 *data,
191 unsigned int len, u8 *out)
192 {
193 return __crc32c_pcl_intel_finup(shash_desc_ctx(desc), data, len, out);
194 }
195
crc32c_pcl_intel_digest(struct shash_desc * desc,const u8 * data,unsigned int len,u8 * out)196 static int crc32c_pcl_intel_digest(struct shash_desc *desc, const u8 *data,
197 unsigned int len, u8 *out)
198 {
199 return __crc32c_pcl_intel_finup(crypto_shash_ctx(desc->tfm), data, len,
200 out);
201 }
202 #endif /* CONFIG_X86_64 */
203
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,
213 .base = {
214 .cra_name = "crc32c",
215 .cra_driver_name = "crc32c-intel",
216 .cra_priority = 200,
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,
222 }
223 };
224
225 static const struct x86_cpu_id crc32c_cpu_id[] = {
226 X86_FEATURE_MATCH(X86_FEATURE_XMM4_2),
227 {}
228 };
229 MODULE_DEVICE_TABLE(x86cpu, crc32c_cpu_id);
230
crc32c_intel_mod_init(void)231 static int __init crc32c_intel_mod_init(void)
232 {
233 if (!x86_match_cpu(crc32c_cpu_id))
234 return -ENODEV;
235 #ifdef CONFIG_X86_64
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;
240 }
241 #endif
242 return crypto_register_shash(&alg);
243 }
244
crc32c_intel_mod_fini(void)245 static void __exit crc32c_intel_mod_fini(void)
246 {
247 crypto_unregister_shash(&alg);
248 }
249
250 module_init(crc32c_intel_mod_init);
251 module_exit(crc32c_intel_mod_fini);
252
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");
256
257 MODULE_ALIAS_CRYPTO("crc32c");
258 MODULE_ALIAS_CRYPTO("crc32c-intel");
259