1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Aug 8, 2011 Bob Pearson with help from Joakim Tjernlund and George Spelvin 4 * cleaned up code to current version of sparse and added the slicing-by-8 5 * algorithm to the closely similar existing slicing-by-4 algorithm. 6 * 7 * Oct 15, 2000 Matt Domsch <Matt_Domsch@dell.com> 8 * Nicer crc32 functions/docs submitted by linux@horizon.com. Thanks! 9 * Code was from the public domain, copyright abandoned. Code was 10 * subsequently included in the kernel, thus was re-licensed under the 11 * GNU GPL v2. 12 * 13 * Oct 12, 2000 Matt Domsch <Matt_Domsch@dell.com> 14 * Same crc32 function was used in 5 other places in the kernel. 15 * I made one version, and deleted the others. 16 * There are various incantations of crc32(). Some use a seed of 0 or ~0. 17 * Some xor at the end with ~0. The generic crc32() function takes 18 * seed as an argument, and doesn't xor at the end. Then individual 19 * users can do whatever they need. 20 * drivers/net/smc9194.c uses seed ~0, doesn't xor with ~0. 21 * fs/jffs2 uses seed 0, doesn't xor with ~0. 22 * fs/partitions/efi.c uses seed ~0, xor's with ~0. 23 */ 24 25 /* see: Documentation/staging/crc32.rst for a description of algorithms */ 26 27 #include <linux/crc32.h> 28 #include <linux/export.h> 29 #include <linux/module.h> 30 #include <linux/types.h> 31 32 #include "crc32table.h" 33 34 static inline u32 __maybe_unused 35 crc32_le_base(u32 crc, const u8 *p, size_t len) 36 { 37 while (len--) 38 crc = (crc >> 8) ^ crc32table_le[(crc & 255) ^ *p++]; 39 return crc; 40 } 41 42 static inline u32 __maybe_unused 43 crc32_be_base(u32 crc, const u8 *p, size_t len) 44 { 45 while (len--) 46 crc = (crc << 8) ^ crc32table_be[(crc >> 24) ^ *p++]; 47 return crc; 48 } 49 50 static inline u32 __maybe_unused 51 crc32c_base(u32 crc, const u8 *p, size_t len) 52 { 53 while (len--) 54 crc = (crc >> 8) ^ crc32ctable_le[(crc & 255) ^ *p++]; 55 return crc; 56 } 57 58 #ifdef CONFIG_CRC32_ARCH 59 #include "crc32.h" /* $(SRCARCH)/crc32.h */ 60 61 u32 crc32_optimizations(void) 62 { 63 return crc32_optimizations_arch(); 64 } 65 EXPORT_SYMBOL(crc32_optimizations); 66 #else 67 #define crc32_le_arch crc32_le_base 68 #define crc32_be_arch crc32_be_base 69 #define crc32c_arch crc32c_base 70 #endif 71 72 u32 crc32_le(u32 crc, const void *p, size_t len) 73 { 74 return crc32_le_arch(crc, p, len); 75 } 76 EXPORT_SYMBOL(crc32_le); 77 78 u32 crc32_be(u32 crc, const void *p, size_t len) 79 { 80 return crc32_be_arch(crc, p, len); 81 } 82 EXPORT_SYMBOL(crc32_be); 83 84 u32 crc32c(u32 crc, const void *p, size_t len) 85 { 86 return crc32c_arch(crc, p, len); 87 } 88 EXPORT_SYMBOL(crc32c); 89 90 #ifdef crc32_mod_init_arch 91 static int __init crc32_mod_init(void) 92 { 93 crc32_mod_init_arch(); 94 return 0; 95 } 96 subsys_initcall(crc32_mod_init); 97 98 static void __exit crc32_mod_exit(void) 99 { 100 } 101 module_exit(crc32_mod_exit); 102 #endif 103 104 MODULE_DESCRIPTION("CRC32 library functions"); 105 MODULE_LICENSE("GPL"); 106