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