93 строки
2.8 KiB
C
93 строки
2.8 KiB
C
/*
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* Some portions derived from code covered by the following notice:
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*
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* Copyright (c) 2010-2013 Intel Corporation. All rights reserved.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* * Neither the name of Intel Corporation nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <linux/hash.h>
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#include <linux/init.h>
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#include <asm/processor.h>
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#include <asm/cpufeature.h>
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#include <asm/hash.h>
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static inline u32 crc32_u32(u32 crc, u32 val)
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{
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#ifdef CONFIG_AS_CRC32
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asm ("crc32l %1,%0\n" : "+r" (crc) : "rm" (val));
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#else
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asm (".byte 0xf2, 0x0f, 0x38, 0xf1, 0xc1" : "+a" (crc) : "c" (val));
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#endif
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return crc;
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}
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static u32 intel_crc4_2_hash(const void *data, u32 len, u32 seed)
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{
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const u32 *p32 = (const u32 *) data;
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u32 i, tmp = 0;
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for (i = 0; i < len / 4; i++)
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seed = crc32_u32(seed, *p32++);
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switch (len & 3) {
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case 3:
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tmp |= *((const u8 *) p32 + 2) << 16;
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/* fallthrough */
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case 2:
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tmp |= *((const u8 *) p32 + 1) << 8;
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/* fallthrough */
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case 1:
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tmp |= *((const u8 *) p32);
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seed = crc32_u32(seed, tmp);
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break;
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}
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return seed;
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}
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static u32 intel_crc4_2_hash2(const u32 *data, u32 len, u32 seed)
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{
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const u32 *p32 = (const u32 *) data;
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u32 i;
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for (i = 0; i < len; i++)
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seed = crc32_u32(seed, *p32++);
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return seed;
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}
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void __init setup_arch_fast_hash(struct fast_hash_ops *ops)
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{
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if (cpu_has_xmm4_2) {
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ops->hash = intel_crc4_2_hash;
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ops->hash2 = intel_crc4_2_hash2;
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}
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}
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