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067bc8717a
Add support for architecture-optimized implementations of the CRC64 library functions, following the approach taken for the CRC32 and CRC-T10DIF library functions. Also take the opportunity to tweak the function prototypes: - Use 'const void *' for the lib entry points (since this is easier for users) but 'const u8 *' for the underlying arch and generic functions (since this is easier for the implementations of these functions). - Don't bother with __pure. It's an unusual optimization that doesn't help properly written code. It's a weird quirk we can do without. Reviewed-by: Ard Biesheuvel <ardb@kernel.org> Reviewed-by: "Martin K. Petersen" <martin.petersen@oracle.com> Acked-by: Keith Busch <kbusch@kernel.org> Link: https://lore.kernel.org/r/20250130035130.180676-6-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com>
58 lines
2 KiB
C
58 lines
2 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Normal 64-bit CRC calculation.
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*
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* This is a basic crc64 implementation following ECMA-182 specification,
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* which can be found from,
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* https://www.ecma-international.org/publications/standards/Ecma-182.htm
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*
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* Dr. Ross N. Williams has a great document to introduce the idea of CRC
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* algorithm, here the CRC64 code is also inspired by the table-driven
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* algorithm and detail example from this paper. This paper can be found
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* from,
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* http://www.ross.net/crc/download/crc_v3.txt
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*
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* crc64table[256] is the lookup table of a table-driven 64-bit CRC
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* calculation, which is generated by gen_crc64table.c in kernel build
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* time. The polynomial of crc64 arithmetic is from ECMA-182 specification
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* as well, which is defined as,
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*
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* x^64 + x^62 + x^57 + x^55 + x^54 + x^53 + x^52 + x^47 + x^46 + x^45 +
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* x^40 + x^39 + x^38 + x^37 + x^35 + x^33 + x^32 + x^31 + x^29 + x^27 +
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* x^24 + x^23 + x^22 + x^21 + x^19 + x^17 + x^13 + x^12 + x^10 + x^9 +
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* x^7 + x^4 + x + 1
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*
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* crc64nvmetable[256] uses the CRC64 polynomial from the NVME NVM Command Set
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* Specification and uses least-significant-bit first bit order:
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*
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* x^64 + x^63 + x^61 + x^59 + x^58 + x^56 + x^55 + x^52 + x^49 + x^48 + x^47 +
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* x^46 + x^44 + x^41 + x^37 + x^36 + x^34 + x^32 + x^31 + x^28 + x^26 + x^23 +
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* x^22 + x^19 + x^16 + x^13 + x^12 + x^10 + x^9 + x^6 + x^4 + x^3 + 1
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*
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* Copyright 2018 SUSE Linux.
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* Author: Coly Li <colyli@suse.de>
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*/
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#include <linux/module.h>
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#include <linux/types.h>
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#include <linux/crc64.h>
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#include "crc64table.h"
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MODULE_DESCRIPTION("CRC64 calculations");
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MODULE_LICENSE("GPL v2");
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u64 crc64_be_generic(u64 crc, const u8 *p, size_t len)
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{
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while (len--)
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crc = (crc << 8) ^ crc64table[(crc >> 56) ^ *p++];
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return crc;
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}
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EXPORT_SYMBOL_GPL(crc64_be_generic);
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u64 crc64_nvme_generic(u64 crc, const u8 *p, size_t len)
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{
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while (len--)
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crc = (crc >> 8) ^ crc64nvmetable[(crc & 0xff) ^ *p++];
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return crc;
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}
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EXPORT_SYMBOL_GPL(crc64_nvme_generic);
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