Line data Source code
1 : /*
2 : * Copied from btrfs-progs, kernel-lib/crc32c.c, which was:
3 : * Copied from the kernel source code, lib/libcrc32c.c.
4 : *
5 : * This program is free software; you can redistribute it and/or modify it
6 : * under the terms of the GNU General Public License as published by the Free
7 : * Software Foundation; either version 2 of the License, or (at your option)
8 : * any later version.
9 : *
10 : */
11 : #include <stdlib.h>
12 : #include <inttypes.h>
13 : #include "crc32c.h"
14 :
15 : static uint32_t __crc32c_le(uint32_t crc, unsigned char const *data, size_t length);
16 : static uint32_t (*crc_function)(uint32_t crc, unsigned char const *data, size_t length) = __crc32c_le;
17 :
18 : #ifdef __x86_64__
19 :
20 : /*
21 : * Based on a posting to lkml by Austin Zhang <austin.zhang@intel.com>
22 : *
23 : * Using hardware provided CRC32 instruction to accelerate the CRC32 disposal.
24 : * CRC32C polynomial:0x1EDC6F41(BE)/0x82F63B78(LE)
25 : * CRC32 is a new instruction in Intel SSE4.2, the reference can be found at:
26 : * http://www.intel.com/products/processor/manuals/
27 : * Intel(R) 64 and IA-32 Architectures Software Developer's Manual
28 : * Volume 2A: Instruction Set Reference, A-M
29 : */
30 : #if __SIZEOF_LONG__ == 8
31 : #define REX_PRE "0x48, "
32 : #define SCALE_F 8
33 : #else
34 : #define REX_PRE
35 : #define SCALE_F 4
36 : #endif
37 :
38 : static int crc32c_probed = 0;
39 : static int crc32c_intel_available = 0;
40 :
41 0 : static uint32_t crc32c_intel_le_hw_byte(uint32_t crc, unsigned char const *data,
42 : unsigned long length)
43 : {
44 0 : while (length--) {
45 0 : __asm__ __volatile__(
46 : ".byte 0xf2, 0xf, 0x38, 0xf0, 0xf1"
47 : :"=S"(crc)
48 0 : :"0"(crc), "c"(*data)
49 : );
50 0 : data++;
51 : }
52 :
53 0 : return crc;
54 : }
55 :
56 : /*
57 : * Steps through buffer one byte at at time, calculates reflected
58 : * crc using table.
59 : */
60 0 : static uint32_t crc32c_intel(uint32_t crc, unsigned char const *data, unsigned long length)
61 : {
62 0 : unsigned int iquotient = length / SCALE_F;
63 0 : unsigned int iremainder = length % SCALE_F;
64 0 : unsigned long *ptmp = (unsigned long *)data;
65 :
66 0 : while (iquotient--) {
67 0 : __asm__ __volatile__(
68 : ".byte 0xf2, " REX_PRE "0xf, 0x38, 0xf1, 0xf1;"
69 : :"=S"(crc)
70 0 : :"0"(crc), "c"(*ptmp)
71 : );
72 0 : ptmp++;
73 : }
74 :
75 0 : if (iremainder)
76 0 : crc = crc32c_intel_le_hw_byte(crc, (unsigned char *)ptmp,
77 : iremainder);
78 :
79 0 : return crc;
80 : }
81 :
82 72 : static void do_cpuid(unsigned int *eax, unsigned int *ebx, unsigned int *ecx,
83 : unsigned int *edx)
84 : {
85 72 : int id = *eax;
86 :
87 72 : asm("movl %4, %%eax;"
88 : "cpuid;"
89 : "movl %%eax, %0;"
90 : "movl %%ebx, %1;"
91 : "movl %%ecx, %2;"
92 : "movl %%edx, %3;"
93 : : "=r" (*eax), "=r" (*ebx), "=r" (*ecx), "=r" (*edx)
94 : : "r" (id)
95 : : "eax", "ebx", "ecx", "edx");
96 72 : }
97 :
98 79 : static void crc32c_intel_probe(void)
99 : {
100 79 : if (!crc32c_probed) {
101 : unsigned int eax, ebx, ecx, edx;
102 :
103 72 : eax = 1;
104 :
105 72 : do_cpuid(&eax, &ebx, &ecx, &edx);
106 72 : crc32c_intel_available = (ecx & (1 << 20)) != 0;
107 72 : crc32c_probed = 1;
108 : }
109 79 : }
110 :
111 79 : void crc32c_optimization_init(void)
112 : {
113 79 : crc32c_intel_probe();
114 79 : if (crc32c_intel_available)
115 79 : crc_function = crc32c_intel;
116 79 : }
117 : #else
118 :
119 : void crc32c_optimization_init(void)
120 : {
121 : }
122 :
123 : #endif /* __x86_64__ */
124 :
125 : /*
126 : * This is the CRC-32C table
127 : * Generated with:
128 : * width = 32 bits
129 : * poly = 0x1EDC6F41
130 : * reflect input bytes = true
131 : * reflect output bytes = true
132 : */
133 :
134 : static const uint32_t crc32c_table[256] = {
135 : 0x00000000L, 0xF26B8303L, 0xE13B70F7L, 0x1350F3F4L,
136 : 0xC79A971FL, 0x35F1141CL, 0x26A1E7E8L, 0xD4CA64EBL,
137 : 0x8AD958CFL, 0x78B2DBCCL, 0x6BE22838L, 0x9989AB3BL,
138 : 0x4D43CFD0L, 0xBF284CD3L, 0xAC78BF27L, 0x5E133C24L,
139 : 0x105EC76FL, 0xE235446CL, 0xF165B798L, 0x030E349BL,
140 : 0xD7C45070L, 0x25AFD373L, 0x36FF2087L, 0xC494A384L,
141 : 0x9A879FA0L, 0x68EC1CA3L, 0x7BBCEF57L, 0x89D76C54L,
142 : 0x5D1D08BFL, 0xAF768BBCL, 0xBC267848L, 0x4E4DFB4BL,
143 : 0x20BD8EDEL, 0xD2D60DDDL, 0xC186FE29L, 0x33ED7D2AL,
144 : 0xE72719C1L, 0x154C9AC2L, 0x061C6936L, 0xF477EA35L,
145 : 0xAA64D611L, 0x580F5512L, 0x4B5FA6E6L, 0xB93425E5L,
146 : 0x6DFE410EL, 0x9F95C20DL, 0x8CC531F9L, 0x7EAEB2FAL,
147 : 0x30E349B1L, 0xC288CAB2L, 0xD1D83946L, 0x23B3BA45L,
148 : 0xF779DEAEL, 0x05125DADL, 0x1642AE59L, 0xE4292D5AL,
149 : 0xBA3A117EL, 0x4851927DL, 0x5B016189L, 0xA96AE28AL,
150 : 0x7DA08661L, 0x8FCB0562L, 0x9C9BF696L, 0x6EF07595L,
151 : 0x417B1DBCL, 0xB3109EBFL, 0xA0406D4BL, 0x522BEE48L,
152 : 0x86E18AA3L, 0x748A09A0L, 0x67DAFA54L, 0x95B17957L,
153 : 0xCBA24573L, 0x39C9C670L, 0x2A993584L, 0xD8F2B687L,
154 : 0x0C38D26CL, 0xFE53516FL, 0xED03A29BL, 0x1F682198L,
155 : 0x5125DAD3L, 0xA34E59D0L, 0xB01EAA24L, 0x42752927L,
156 : 0x96BF4DCCL, 0x64D4CECFL, 0x77843D3BL, 0x85EFBE38L,
157 : 0xDBFC821CL, 0x2997011FL, 0x3AC7F2EBL, 0xC8AC71E8L,
158 : 0x1C661503L, 0xEE0D9600L, 0xFD5D65F4L, 0x0F36E6F7L,
159 : 0x61C69362L, 0x93AD1061L, 0x80FDE395L, 0x72966096L,
160 : 0xA65C047DL, 0x5437877EL, 0x4767748AL, 0xB50CF789L,
161 : 0xEB1FCBADL, 0x197448AEL, 0x0A24BB5AL, 0xF84F3859L,
162 : 0x2C855CB2L, 0xDEEEDFB1L, 0xCDBE2C45L, 0x3FD5AF46L,
163 : 0x7198540DL, 0x83F3D70EL, 0x90A324FAL, 0x62C8A7F9L,
164 : 0xB602C312L, 0x44694011L, 0x5739B3E5L, 0xA55230E6L,
165 : 0xFB410CC2L, 0x092A8FC1L, 0x1A7A7C35L, 0xE811FF36L,
166 : 0x3CDB9BDDL, 0xCEB018DEL, 0xDDE0EB2AL, 0x2F8B6829L,
167 : 0x82F63B78L, 0x709DB87BL, 0x63CD4B8FL, 0x91A6C88CL,
168 : 0x456CAC67L, 0xB7072F64L, 0xA457DC90L, 0x563C5F93L,
169 : 0x082F63B7L, 0xFA44E0B4L, 0xE9141340L, 0x1B7F9043L,
170 : 0xCFB5F4A8L, 0x3DDE77ABL, 0x2E8E845FL, 0xDCE5075CL,
171 : 0x92A8FC17L, 0x60C37F14L, 0x73938CE0L, 0x81F80FE3L,
172 : 0x55326B08L, 0xA759E80BL, 0xB4091BFFL, 0x466298FCL,
173 : 0x1871A4D8L, 0xEA1A27DBL, 0xF94AD42FL, 0x0B21572CL,
174 : 0xDFEB33C7L, 0x2D80B0C4L, 0x3ED04330L, 0xCCBBC033L,
175 : 0xA24BB5A6L, 0x502036A5L, 0x4370C551L, 0xB11B4652L,
176 : 0x65D122B9L, 0x97BAA1BAL, 0x84EA524EL, 0x7681D14DL,
177 : 0x2892ED69L, 0xDAF96E6AL, 0xC9A99D9EL, 0x3BC21E9DL,
178 : 0xEF087A76L, 0x1D63F975L, 0x0E330A81L, 0xFC588982L,
179 : 0xB21572C9L, 0x407EF1CAL, 0x532E023EL, 0xA145813DL,
180 : 0x758FE5D6L, 0x87E466D5L, 0x94B49521L, 0x66DF1622L,
181 : 0x38CC2A06L, 0xCAA7A905L, 0xD9F75AF1L, 0x2B9CD9F2L,
182 : 0xFF56BD19L, 0x0D3D3E1AL, 0x1E6DCDEEL, 0xEC064EEDL,
183 : 0xC38D26C4L, 0x31E6A5C7L, 0x22B65633L, 0xD0DDD530L,
184 : 0x0417B1DBL, 0xF67C32D8L, 0xE52CC12CL, 0x1747422FL,
185 : 0x49547E0BL, 0xBB3FFD08L, 0xA86F0EFCL, 0x5A048DFFL,
186 : 0x8ECEE914L, 0x7CA56A17L, 0x6FF599E3L, 0x9D9E1AE0L,
187 : 0xD3D3E1ABL, 0x21B862A8L, 0x32E8915CL, 0xC083125FL,
188 : 0x144976B4L, 0xE622F5B7L, 0xF5720643L, 0x07198540L,
189 : 0x590AB964L, 0xAB613A67L, 0xB831C993L, 0x4A5A4A90L,
190 : 0x9E902E7BL, 0x6CFBAD78L, 0x7FAB5E8CL, 0x8DC0DD8FL,
191 : 0xE330A81AL, 0x115B2B19L, 0x020BD8EDL, 0xF0605BEEL,
192 : 0x24AA3F05L, 0xD6C1BC06L, 0xC5914FF2L, 0x37FACCF1L,
193 : 0x69E9F0D5L, 0x9B8273D6L, 0x88D28022L, 0x7AB90321L,
194 : 0xAE7367CAL, 0x5C18E4C9L, 0x4F48173DL, 0xBD23943EL,
195 : 0xF36E6F75L, 0x0105EC76L, 0x12551F82L, 0xE03E9C81L,
196 : 0x34F4F86AL, 0xC69F7B69L, 0xD5CF889DL, 0x27A40B9EL,
197 : 0x79B737BAL, 0x8BDCB4B9L, 0x988C474DL, 0x6AE7C44EL,
198 : 0xBE2DA0A5L, 0x4C4623A6L, 0x5F16D052L, 0xAD7D5351L
199 : };
200 :
201 : /*
202 : * Steps through buffer one byte at at time, calculates reflected
203 : * crc using table.
204 : */
205 :
206 4376533 : static uint32_t __crc32c_le(uint32_t crc, unsigned char const *data, size_t length)
207 : {
208 15806075025 : while (length--)
209 15801698492 : crc =
210 15801698492 : crc32c_table[(crc ^ *data++) & 0xFFL] ^ (crc >> 8);
211 4376533 : return crc;
212 : }
213 :
214 4376533 : uint32_t crc32c(uint32_t crc, unsigned char const *data, size_t length)
215 : {
216 : /* Use by-byte access for unaligned buffers */
217 4376533 : if ((unsigned long)data % sizeof(unsigned long))
218 4376533 : return __crc32c_le(crc, data, length);
219 :
220 0 : return crc_function(crc, data, length);
221 : }
|
