x86/crypto/crc32-pclmul_glue.c

0001 /* GPL HEADER START
0002  *
0003  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
0004  *
0005  * This program is free software; you can redistribute it and/or modify
0006  * it under the terms of the GNU General Public License version 2 only,
0007  * as published by the Free Software Foundation.
0008  *
0009  * This program is distributed in the hope that it will be useful, but
0010  * WITHOUT ANY WARRANTY; without even the implied warranty of
0011  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
0012  * General Public License version 2 for more details (a copy is included
0013  * in the LICENSE file that accompanied this code).
0014  *
0015  * You should have received a copy of the GNU General Public License
0016  * version 2 along with this program; If not, see http://www.gnu.org/licenses
0017  *
0018  * Please  visit http://www.xyratex.com/contact if you need additional
0019  * information or have any questions.
0020  *
0021  * GPL HEADER END
0022  */
0023
0024 /*
0025  * Copyright 2012 Xyratex Technology Limited
0026  *
0027  * Wrappers for kernel crypto shash api to pclmulqdq crc32 implementation.
0028  */
0029 #include <linux/init.h>
0030 #include <linux/module.h>
0031 #include <linux/string.h>
0032 #include <linux/kernel.h>
0033 #include <linux/crc32.h>
0034 #include <crypto/internal/hash.h>
0035 #include <crypto/internal/simd.h>
0036
0037 #include <asm/cpufeatures.h>
0038 #include <asm/cpu_device_id.h>
0039 #include <asm/simd.h>
0040
0041 #define CHKSUM_BLOCK_SIZE   1
0042 #define CHKSUM_DIGEST_SIZE  4
0043
0044 #define PCLMUL_MIN_LEN      64L     /* minimum size of buffer
0045                      * for crc32_pclmul_le_16 */
0046 #define SCALE_F         16L /* size of xmm register */
0047 #define SCALE_F_MASK        (SCALE_F - 1)
0048
0049 u32 crc32_pclmul_le_16(unsigned char const *buffer, size_t len, u32 crc32);
0050
0051 static u32 __attribute__((pure))
0052     crc32_pclmul_le(u32 crc, unsigned char const *p, size_t len)
0053 {
0054     unsigned int iquotient;
0055     unsigned int iremainder;
0056     unsigned int prealign;
0057
0058     if (len < PCLMUL_MIN_LEN + SCALE_F_MASK || !crypto_simd_usable())
0059         return crc32_le(crc, p, len);
0060
0061     if ((long)p & SCALE_F_MASK) {
0062         /* align p to 16 byte */
0063         prealign = SCALE_F - ((long)p & SCALE_F_MASK);
0064
0065         crc = crc32_le(crc, p, prealign);
0066         len -= prealign;
0067         p = (unsigned char *)(((unsigned long)p + SCALE_F_MASK) &
0068                      ~SCALE_F_MASK);
0069     }
0070     iquotient = len & (~SCALE_F_MASK);
0071     iremainder = len & SCALE_F_MASK;
0072
0073     kernel_fpu_begin();
0074     crc = crc32_pclmul_le_16(p, iquotient, crc);
0075     kernel_fpu_end();
0076
0077     if (iremainder)
0078         crc = crc32_le(crc, p + iquotient, iremainder);
0079
0080     return crc;
0081 }
0082
0083 static int crc32_pclmul_cra_init(struct crypto_tfm *tfm)
0084 {
0085     u32 *key = crypto_tfm_ctx(tfm);
0086
0087     *key = 0;
0088
0089     return 0;
0090 }
0091
0092 static int crc32_pclmul_setkey(struct crypto_shash *hash, const u8 *key,
0093             unsigned int keylen)
0094 {
0095     u32 *mctx = crypto_shash_ctx(hash);
0096
0097     if (keylen != sizeof(u32))
0098         return -EINVAL;
0099     *mctx = le32_to_cpup((__le32 *)key);
0100     return 0;
0101 }
0102
0103 static int crc32_pclmul_init(struct shash_desc *desc)
0104 {
0105     u32 *mctx = crypto_shash_ctx(desc->tfm);
0106     u32 *crcp = shash_desc_ctx(desc);
0107
0108     *crcp = *mctx;
0109
0110     return 0;
0111 }
0112
0113 static int crc32_pclmul_update(struct shash_desc *desc, const u8 *data,
0114                    unsigned int len)
0115 {
0116     u32 *crcp = shash_desc_ctx(desc);
0117
0118     *crcp = crc32_pclmul_le(*crcp, data, len);
0119     return 0;
0120 }
0121
0122 /* No final XOR 0xFFFFFFFF, like crc32_le */
0123 static int __crc32_pclmul_finup(u32 *crcp, const u8 *data, unsigned int len,
0124                 u8 *out)
0125 {
0126     *(__le32 *)out = cpu_to_le32(crc32_pclmul_le(*crcp, data, len));
0127     return 0;
0128 }
0129
0130 static int crc32_pclmul_finup(struct shash_desc *desc, const u8 *data,
0131                   unsigned int len, u8 *out)
0132 {
0133     return __crc32_pclmul_finup(shash_desc_ctx(desc), data, len, out);
0134 }
0135
0136 static int crc32_pclmul_final(struct shash_desc *desc, u8 *out)
0137 {
0138     u32 *crcp = shash_desc_ctx(desc);
0139
0140     *(__le32 *)out = cpu_to_le32p(crcp);
0141     return 0;
0142 }
0143
0144 static int crc32_pclmul_digest(struct shash_desc *desc, const u8 *data,
0145                    unsigned int len, u8 *out)
0146 {
0147     return __crc32_pclmul_finup(crypto_shash_ctx(desc->tfm), data, len,
0148                     out);
0149 }
0150
0151 static struct shash_alg alg = {
0152     .setkey     = crc32_pclmul_setkey,
0153     .init       = crc32_pclmul_init,
0154     .update     = crc32_pclmul_update,
0155     .final      = crc32_pclmul_final,
0156     .finup      = crc32_pclmul_finup,
0157     .digest     = crc32_pclmul_digest,
0158     .descsize   = sizeof(u32),
0159     .digestsize = CHKSUM_DIGEST_SIZE,
0160     .base       = {
0161             .cra_name       = "crc32",
0162             .cra_driver_name    = "crc32-pclmul",
0163             .cra_priority       = 200,
0164             .cra_flags      = CRYPTO_ALG_OPTIONAL_KEY,
0165             .cra_blocksize      = CHKSUM_BLOCK_SIZE,
0166             .cra_ctxsize        = sizeof(u32),
0167             .cra_module     = THIS_MODULE,
0168             .cra_init       = crc32_pclmul_cra_init,
0169     }
0170 };
0171
0172 static const struct x86_cpu_id crc32pclmul_cpu_id[] = {
0173     X86_MATCH_FEATURE(X86_FEATURE_PCLMULQDQ, NULL),
0174     {}
0175 };
0176 MODULE_DEVICE_TABLE(x86cpu, crc32pclmul_cpu_id);
0177
0178
0179 static int __init crc32_pclmul_mod_init(void)
0180 {
0181
0182     if (!x86_match_cpu(crc32pclmul_cpu_id)) {
0183         pr_info("PCLMULQDQ-NI instructions are not detected.\n");
0184         return -ENODEV;
0185     }
0186     return crypto_register_shash(&alg);
0187 }
0188
0189 static void __exit crc32_pclmul_mod_fini(void)
0190 {
0191     crypto_unregister_shash(&alg);
0192 }
0193
0194 module_init(crc32_pclmul_mod_init);
0195 module_exit(crc32_pclmul_mod_fini);
0196
0197 MODULE_AUTHOR("Alexander Boyko <alexander_boyko@xyratex.com>");
0198 MODULE_LICENSE("GPL");
0199
0200 MODULE_ALIAS_CRYPTO("crc32");
0201 MODULE_ALIAS_CRYPTO("crc32-pclmul");