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d352ac68 CM |
1 | /* |
2 | * Copyright (C) 2008 Oracle. All rights reserved. | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or | |
5 | * modify it under the terms of the GNU General Public | |
6 | * License v2 as published by the Free Software Foundation. | |
7 | * | |
8 | * This program is distributed in the hope that it will be useful, | |
9 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
11 | * General Public License for more details. | |
12 | * | |
13 | * You should have received a copy of the GNU General Public | |
14 | * License along with this program; if not, write to the | |
15 | * Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
16 | * Boston, MA 021110-1307, USA. | |
17 | */ | |
18 | ||
3117a773 CM |
19 | #ifndef __BTRFS_CRC32C__ |
20 | #define __BTRFS_CRC32C__ | |
a5eb62e3 M |
21 | #include <asm/byteorder.h> |
22 | #include <linux/crc32c.h> | |
23 | #include <linux/version.h> | |
24 | ||
3117a773 CM |
25 | /* #define CONFIG_BTRFS_HW_SUM 1 */ |
26 | ||
27 | #ifdef CONFIG_BTRFS_HW_SUM | |
28 | #ifdef CONFIG_X86 | |
29 | /* | |
30 | * Using hardware provided CRC32 instruction to accelerate the CRC32 disposal. | |
31 | * CRC32C polynomial:0x1EDC6F41(BE)/0x82F63B78(LE) | |
32 | * CRC32 is a new instruction in Intel SSE4.2, the reference can be found at: | |
33 | * http://www.intel.com/products/processor/manuals/ | |
34 | * Intel(R) 64 and IA-32 Architectures Software Developer's Manual | |
35 | * Volume 2A: Instruction Set Reference, A-M | |
36 | */ | |
37 | ||
38 | #include <asm/cpufeature.h> | |
39 | #include <asm/processor.h> | |
40 | ||
41 | #define X86_FEATURE_XMM4_2 (4*32+20) /* Streaming SIMD Extensions-4.2 */ | |
42 | #define cpu_has_xmm4_2 boot_cpu_has(X86_FEATURE_XMM4_2) | |
43 | ||
44 | #ifdef CONFIG_X86_64 | |
45 | #define REX_PRE "0x48, " | |
46 | #define SCALE_F 8 | |
47 | #else | |
48 | #define REX_PRE | |
49 | #define SCALE_F 4 | |
50 | #endif | |
51 | ||
52 | static inline u32 btrfs_crc32c_le_hw_byte(u32 crc, unsigned char const *data, | |
53 | size_t length) | |
54 | { | |
55 | while (length--) { | |
56 | __asm__ __volatile__( | |
57 | ".byte 0xf2, 0xf, 0x38, 0xf0, 0xf1" | |
58 | :"=S"(crc) | |
59 | :"0"(crc), "c"(*data) | |
60 | ); | |
61 | data++; | |
62 | } | |
63 | ||
64 | return crc; | |
65 | } | |
66 | ||
67 | static inline u32 __pure btrfs_crc32c_le_hw(u32 crc, unsigned char const *p, | |
68 | size_t len) | |
69 | { | |
70 | unsigned int iquotient = len / SCALE_F; | |
71 | unsigned int iremainder = len % SCALE_F; | |
72 | #ifdef CONFIG_X86_64 | |
73 | u64 *ptmp = (u64 *)p; | |
74 | #else | |
75 | u32 *ptmp = (u32 *)p; | |
76 | #endif | |
77 | ||
78 | while (iquotient--) { | |
79 | __asm__ __volatile__( | |
80 | ".byte 0xf2, " REX_PRE "0xf, 0x38, 0xf1, 0xf1;" | |
81 | :"=S"(crc) | |
82 | :"0"(crc), "c"(*ptmp) | |
83 | ); | |
84 | ptmp++; | |
85 | } | |
86 | ||
87 | if (iremainder) | |
88 | crc = btrfs_crc32c_le_hw_byte(crc, (unsigned char *)ptmp, | |
89 | iremainder); | |
90 | ||
91 | return crc; | |
92 | } | |
93 | #endif /* CONFIG_BTRFS_HW_SUM */ | |
94 | ||
95 | static inline u32 __btrfs_crc32c(u32 crc, unsigned char const *address, | |
96 | size_t len) | |
97 | { | |
98 | #ifdef CONFIG_BTRFS_HW_SUM | |
99 | if (cpu_has_xmm4_2) | |
100 | return btrfs_crc32c_le_hw(crc, address, len); | |
101 | #endif | |
102 | return crc32c_le(crc, address, len); | |
103 | } | |
104 | ||
105 | #else | |
106 | ||
107 | #define __btrfs_crc32c(seed, data, length) crc32c(seed, data, length) | |
108 | ||
109 | #endif /* CONFIG_X86 */ | |
110 | ||
a5eb62e3 M |
111 | /** |
112 | * implementation of crc32c_le() changed in linux-2.6.23, | |
113 | * has of v0.13 btrfs-progs is using the latest version. | |
114 | * We must workaround older implementations of crc32c_le() | |
115 | * found on older kernel versions. | |
116 | */ | |
a5eb62e3 | 117 | #define btrfs_crc32c(seed, data, length) \ |
3117a773 CM |
118 | __btrfs_crc32c(seed, (unsigned char const *)data, length) |
119 | #endif | |
3117a773 | 120 |