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