1/*
 2 * Some portions derived from code covered by the following notice:
 3 *
 4 * Copyright (c) 2010-2013 Intel Corporation. All rights reserved.
 5 * All rights reserved.
 6 *
 7 * Redistribution and use in source and binary forms, with or without
 8 * modification, are permitted provided that the following conditions
 9 * are met:
10 *
11 *   * Redistributions of source code must retain the above copyright
12 *     notice, this list of conditions and the following disclaimer.
13 *   * Redistributions in binary form must reproduce the above copyright
14 *     notice, this list of conditions and the following disclaimer in
15 *     the documentation and/or other materials provided with the
16 *     distribution.
17 *   * Neither the name of Intel Corporation nor the names of its
18 *     contributors may be used to endorse or promote products derived
19 *     from this software without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
24 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
25 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
26 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
27 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
28 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
29 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
30 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
31 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 */
33
34#include <linux/hash.h>
35#include <linux/init.h>
36
37#include <asm/processor.h>
38#include <asm/cpufeature.h>
39#include <asm/hash.h>
40
41static inline u32 crc32_u32(u32 crc, u32 val)
42{
43#ifdef CONFIG_AS_CRC32
44	asm ("crc32l %1,%0\n" : "+r" (crc) : "rm" (val));
45#else
46	asm (".byte 0xf2, 0x0f, 0x38, 0xf1, 0xc1" : "+a" (crc) : "c" (val));
47#endif
48	return crc;
49}
50
51static u32 intel_crc4_2_hash(const void *data, u32 len, u32 seed)
52{
53	const u32 *p32 = (const u32 *) data;
54	u32 i, tmp = 0;
55
56	for (i = 0; i < len / 4; i++)
57		seed = crc32_u32(seed, *p32++);
58
59	switch (len & 3) {
60	case 3:
61		tmp |= *((const u8 *) p32 + 2) << 16;
62		/* fallthrough */
63	case 2:
64		tmp |= *((const u8 *) p32 + 1) << 8;
65		/* fallthrough */
66	case 1:
67		tmp |= *((const u8 *) p32);
68		seed = crc32_u32(seed, tmp);
69		break;
70	}
71
72	return seed;
73}
74
75static u32 intel_crc4_2_hash2(const u32 *data, u32 len, u32 seed)
76{
77	const u32 *p32 = (const u32 *) data;
78	u32 i;
79
80	for (i = 0; i < len; i++)
81		seed = crc32_u32(seed, *p32++);
82
83	return seed;
84}
85
86void __init setup_arch_fast_hash(struct fast_hash_ops *ops)
87{
88	if (cpu_has_xmm4_2) {
89		ops->hash  = intel_crc4_2_hash;
90		ops->hash2 = intel_crc4_2_hash2;
91	}
92}