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/*
* Calculate a CRC T10-DIF with vpmsum acceleration
*
* Copyright 2017, Daniel Axtens, IBM Corporation.
* [based on crc32c-vpmsum_glue.c]
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*/
#include <linux/crc-t10dif.h>
#include <crypto/internal/hash.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/cpufeature.h>
#include <asm/switch_to.h>
#define VMX_ALIGN 16
#define VMX_ALIGN_MASK (VMX_ALIGN-1)
#define VECTOR_BREAKPOINT 64
u32 __crct10dif_vpmsum(u32 crc, unsigned char const *p, size_t len);
static u16 crct10dif_vpmsum(u16 crci, unsigned char const *p, size_t len)
{
unsigned int prealign;
unsigned int tail;
u32 crc = crci;
if (len < (VECTOR_BREAKPOINT + VMX_ALIGN) || in_interrupt())
return crc_t10dif_generic(crc, p, len);
if ((unsigned long)p & VMX_ALIGN_MASK) {
prealign = VMX_ALIGN - ((unsigned long)p & VMX_ALIGN_MASK);
crc = crc_t10dif_generic(crc, p, prealign);
len -= prealign;
p += prealign;
}
if (len & ~VMX_ALIGN_MASK) {
crc <<= 16;
preempt_disable();
pagefault_disable();
enable_kernel_altivec();
crc = __crct10dif_vpmsum(crc, p, len & ~VMX_ALIGN_MASK);
disable_kernel_altivec();
pagefault_enable();
preempt_enable();
crc >>= 16;
}
tail = len & VMX_ALIGN_MASK;
if (tail) {
p += len & ~VMX_ALIGN_MASK;
crc = crc_t10dif_generic(crc, p, tail);
}
return crc & 0xffff;
}
static int crct10dif_vpmsum_init(struct shash_desc *desc)
{
u16 *crc = shash_desc_ctx(desc);
*crc = 0;
return 0;
}
static int crct10dif_vpmsum_update(struct shash_desc *desc, const u8 *data,
unsigned int length)
{
u16 *crc = shash_desc_ctx(desc);
*crc = crct10dif_vpmsum(*crc, data, length);
return 0;
}
static int crct10dif_vpmsum_final(struct shash_desc *desc, u8 *out)
{
u16 *crcp = shash_desc_ctx(desc);
*(u16 *)out = *crcp;
return 0;
}
static struct shash_alg alg = {
.init = crct10dif_vpmsum_init,
.update = crct10dif_vpmsum_update,
.final = crct10dif_vpmsum_final,
.descsize = CRC_T10DIF_DIGEST_SIZE,
.digestsize = CRC_T10DIF_DIGEST_SIZE,
.base = {
.cra_name = "crct10dif",
.cra_driver_name = "crct10dif-vpmsum",
.cra_priority = 200,
.cra_blocksize = CRC_T10DIF_BLOCK_SIZE,
.cra_module = THIS_MODULE,
}
};
static int __init crct10dif_vpmsum_mod_init(void)
{
if (!cpu_has_feature(CPU_FTR_ARCH_207S))
return -ENODEV;
return crypto_register_shash(&alg);
}
static void __exit crct10dif_vpmsum_mod_fini(void)
{
crypto_unregister_shash(&alg);
}
module_cpu_feature_match(PPC_MODULE_FEATURE_VEC_CRYPTO, crct10dif_vpmsum_mod_init);
module_exit(crct10dif_vpmsum_mod_fini);
MODULE_AUTHOR("Daniel Axtens <dja@axtens.net>");
MODULE_DESCRIPTION("CRCT10DIF using vector polynomial multiply-sum instructions");
MODULE_LICENSE("GPL");
MODULE_ALIAS_CRYPTO("crct10dif");
MODULE_ALIAS_CRYPTO("crct10dif-vpmsum");
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