203 lines
5 KiB
C
203 lines
5 KiB
C
/* GPL HEADER START
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*
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 only,
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* as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License version 2 for more details (a copy is included
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* in the LICENSE file that accompanied this code).
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*
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* You should have received a copy of the GNU General Public License
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* version 2 along with this program; If not, see http://www.gnu.org/licenses
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*
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* Please visit http://www.xyratex.com/contact if you need additional
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* information or have any questions.
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*
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* GPL HEADER END
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*/
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/*
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* Copyright 2012 Xyratex Technology Limited
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*
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* Wrappers for kernel crypto shash api to pclmulqdq crc32 imlementation.
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*/
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/string.h>
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#include <linux/kernel.h>
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#include <linux/crc32.h>
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#include <crypto/internal/hash.h>
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#include <asm/cpufeatures.h>
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#include <asm/cpu_device_id.h>
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#include <asm/fpu/api.h>
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#define CHKSUM_BLOCK_SIZE 1
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#define CHKSUM_DIGEST_SIZE 4
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#define PCLMUL_MIN_LEN 64L /* minimum size of buffer
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* for crc32_pclmul_le_16 */
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#define SCALE_F 16L /* size of xmm register */
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#define SCALE_F_MASK (SCALE_F - 1)
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u32 crc32_pclmul_le_16(unsigned char const *buffer, size_t len, u32 crc32);
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static u32 __attribute__((pure))
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crc32_pclmul_le(u32 crc, unsigned char const *p, size_t len)
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{
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unsigned int iquotient;
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unsigned int iremainder;
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unsigned int prealign;
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if (len < PCLMUL_MIN_LEN + SCALE_F_MASK || !irq_fpu_usable())
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return crc32_le(crc, p, len);
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if ((long)p & SCALE_F_MASK) {
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/* align p to 16 byte */
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prealign = SCALE_F - ((long)p & SCALE_F_MASK);
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crc = crc32_le(crc, p, prealign);
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len -= prealign;
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p = (unsigned char *)(((unsigned long)p + SCALE_F_MASK) &
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~SCALE_F_MASK);
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}
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iquotient = len & (~SCALE_F_MASK);
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iremainder = len & SCALE_F_MASK;
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kernel_fpu_begin();
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crc = crc32_pclmul_le_16(p, iquotient, crc);
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kernel_fpu_end();
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if (iremainder)
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crc = crc32_le(crc, p + iquotient, iremainder);
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return crc;
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}
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static int crc32_pclmul_cra_init(struct crypto_tfm *tfm)
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{
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u32 *key = crypto_tfm_ctx(tfm);
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*key = 0;
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return 0;
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}
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static int crc32_pclmul_setkey(struct crypto_shash *hash, const u8 *key,
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unsigned int keylen)
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{
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u32 *mctx = crypto_shash_ctx(hash);
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if (keylen != sizeof(u32)) {
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crypto_shash_set_flags(hash, CRYPTO_TFM_RES_BAD_KEY_LEN);
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return -EINVAL;
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}
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*mctx = le32_to_cpup((__le32 *)key);
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return 0;
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}
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static int crc32_pclmul_init(struct shash_desc *desc)
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{
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u32 *mctx = crypto_shash_ctx(desc->tfm);
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u32 *crcp = shash_desc_ctx(desc);
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*crcp = *mctx;
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return 0;
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}
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static int crc32_pclmul_update(struct shash_desc *desc, const u8 *data,
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unsigned int len)
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{
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u32 *crcp = shash_desc_ctx(desc);
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*crcp = crc32_pclmul_le(*crcp, data, len);
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return 0;
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}
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/* No final XOR 0xFFFFFFFF, like crc32_le */
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static int __crc32_pclmul_finup(u32 *crcp, const u8 *data, unsigned int len,
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u8 *out)
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{
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*(__le32 *)out = cpu_to_le32(crc32_pclmul_le(*crcp, data, len));
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return 0;
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}
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static int crc32_pclmul_finup(struct shash_desc *desc, const u8 *data,
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unsigned int len, u8 *out)
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{
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return __crc32_pclmul_finup(shash_desc_ctx(desc), data, len, out);
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}
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static int crc32_pclmul_final(struct shash_desc *desc, u8 *out)
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{
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u32 *crcp = shash_desc_ctx(desc);
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*(__le32 *)out = cpu_to_le32p(crcp);
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return 0;
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}
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static int crc32_pclmul_digest(struct shash_desc *desc, const u8 *data,
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unsigned int len, u8 *out)
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{
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return __crc32_pclmul_finup(crypto_shash_ctx(desc->tfm), data, len,
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out);
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}
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static struct shash_alg alg = {
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.setkey = crc32_pclmul_setkey,
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.init = crc32_pclmul_init,
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.update = crc32_pclmul_update,
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.final = crc32_pclmul_final,
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.finup = crc32_pclmul_finup,
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.digest = crc32_pclmul_digest,
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.descsize = sizeof(u32),
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.digestsize = CHKSUM_DIGEST_SIZE,
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.base = {
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.cra_name = "crc32",
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.cra_driver_name = "crc32-pclmul",
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.cra_priority = 200,
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.cra_flags = CRYPTO_ALG_OPTIONAL_KEY,
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.cra_blocksize = CHKSUM_BLOCK_SIZE,
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.cra_ctxsize = sizeof(u32),
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.cra_module = THIS_MODULE,
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.cra_init = crc32_pclmul_cra_init,
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}
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};
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static const struct x86_cpu_id crc32pclmul_cpu_id[] = {
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X86_FEATURE_MATCH(X86_FEATURE_PCLMULQDQ),
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{}
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};
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MODULE_DEVICE_TABLE(x86cpu, crc32pclmul_cpu_id);
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static int __init crc32_pclmul_mod_init(void)
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{
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if (!x86_match_cpu(crc32pclmul_cpu_id)) {
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pr_info("PCLMULQDQ-NI instructions are not detected.\n");
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return -ENODEV;
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}
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return crypto_register_shash(&alg);
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}
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static void __exit crc32_pclmul_mod_fini(void)
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{
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crypto_unregister_shash(&alg);
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}
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module_init(crc32_pclmul_mod_init);
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module_exit(crc32_pclmul_mod_fini);
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MODULE_AUTHOR("Alexander Boyko <alexander_boyko@xyratex.com>");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS_CRYPTO("crc32");
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MODULE_ALIAS_CRYPTO("crc32-pclmul");
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