diff options
Diffstat (limited to 'lib/crc32.c')
| -rw-r--r-- | lib/crc32.c | 344 |
1 files changed, 0 insertions, 344 deletions
diff --git a/lib/crc32.c b/lib/crc32.c deleted file mode 100644 index 5649847d0a8d..000000000000 --- a/lib/crc32.c +++ /dev/null @@ -1,344 +0,0 @@ -/* - * Aug 8, 2011 Bob Pearson with help from Joakim Tjernlund and George Spelvin - * cleaned up code to current version of sparse and added the slicing-by-8 - * algorithm to the closely similar existing slicing-by-4 algorithm. - * - * Oct 15, 2000 Matt Domsch <Matt_Domsch@dell.com> - * Nicer crc32 functions/docs submitted by linux@horizon.com. Thanks! - * Code was from the public domain, copyright abandoned. Code was - * subsequently included in the kernel, thus was re-licensed under the - * GNU GPL v2. - * - * Oct 12, 2000 Matt Domsch <Matt_Domsch@dell.com> - * Same crc32 function was used in 5 other places in the kernel. - * I made one version, and deleted the others. - * There are various incantations of crc32(). Some use a seed of 0 or ~0. - * Some xor at the end with ~0. The generic crc32() function takes - * seed as an argument, and doesn't xor at the end. Then individual - * users can do whatever they need. - * drivers/net/smc9194.c uses seed ~0, doesn't xor with ~0. - * fs/jffs2 uses seed 0, doesn't xor with ~0. - * fs/partitions/efi.c uses seed ~0, xor's with ~0. - * - * This source code is licensed under the GNU General Public License, - * Version 2. See the file COPYING for more details. - */ - -/* see: Documentation/staging/crc32.rst for a description of algorithms */ - -#include <linux/crc32.h> -#include <linux/crc32poly.h> -#include <linux/module.h> -#include <linux/types.h> -#include <linux/sched.h> -#include "crc32defs.h" - -#if CRC_LE_BITS > 8 -# define tole(x) ((__force u32) cpu_to_le32(x)) -#else -# define tole(x) (x) -#endif - -#if CRC_BE_BITS > 8 -# define tobe(x) ((__force u32) cpu_to_be32(x)) -#else -# define tobe(x) (x) -#endif - -#include "crc32table.h" - -MODULE_AUTHOR("Matt Domsch <Matt_Domsch@dell.com>"); -MODULE_DESCRIPTION("Various CRC32 calculations"); -MODULE_LICENSE("GPL"); - -#if CRC_LE_BITS > 8 || CRC_BE_BITS > 8 - -/* implements slicing-by-4 or slicing-by-8 algorithm */ -static inline u32 __pure -crc32_body(u32 crc, unsigned char const *buf, size_t len, const u32 (*tab)[256]) -{ -# ifdef __LITTLE_ENDIAN -# define DO_CRC(x) crc = t0[(crc ^ (x)) & 255] ^ (crc >> 8) -# define DO_CRC4 (t3[(q) & 255] ^ t2[(q >> 8) & 255] ^ \ - t1[(q >> 16) & 255] ^ t0[(q >> 24) & 255]) -# define DO_CRC8 (t7[(q) & 255] ^ t6[(q >> 8) & 255] ^ \ - t5[(q >> 16) & 255] ^ t4[(q >> 24) & 255]) -# else -# define DO_CRC(x) crc = t0[((crc >> 24) ^ (x)) & 255] ^ (crc << 8) -# define DO_CRC4 (t0[(q) & 255] ^ t1[(q >> 8) & 255] ^ \ - t2[(q >> 16) & 255] ^ t3[(q >> 24) & 255]) -# define DO_CRC8 (t4[(q) & 255] ^ t5[(q >> 8) & 255] ^ \ - t6[(q >> 16) & 255] ^ t7[(q >> 24) & 255]) -# endif - const u32 *b; - size_t rem_len; -# ifdef CONFIG_X86 - size_t i; -# endif - const u32 *t0=tab[0], *t1=tab[1], *t2=tab[2], *t3=tab[3]; -# if CRC_LE_BITS != 32 - const u32 *t4 = tab[4], *t5 = tab[5], *t6 = tab[6], *t7 = tab[7]; -# endif - u32 q; - - /* Align it */ - if (unlikely((long)buf & 3 && len)) { - do { - DO_CRC(*buf++); - } while ((--len) && ((long)buf)&3); - } - -# if CRC_LE_BITS == 32 - rem_len = len & 3; - len = len >> 2; -# else - rem_len = len & 7; - len = len >> 3; -# endif - - b = (const u32 *)buf; -# ifdef CONFIG_X86 - --b; - for (i = 0; i < len; i++) { -# else - for (--b; len; --len) { -# endif - q = crc ^ *++b; /* use pre increment for speed */ -# if CRC_LE_BITS == 32 - crc = DO_CRC4; -# else - crc = DO_CRC8; - q = *++b; - crc ^= DO_CRC4; -# endif - } - len = rem_len; - /* And the last few bytes */ - if (len) { - u8 *p = (u8 *)(b + 1) - 1; -# ifdef CONFIG_X86 - for (i = 0; i < len; i++) - DO_CRC(*++p); /* use pre increment for speed */ -# else - do { - DO_CRC(*++p); /* use pre increment for speed */ - } while (--len); -# endif - } - return crc; -#undef DO_CRC -#undef DO_CRC4 -#undef DO_CRC8 -} -#endif - - -/** - * crc32_le_generic() - Calculate bitwise little-endian Ethernet AUTODIN II - * CRC32/CRC32C - * @crc: seed value for computation. ~0 for Ethernet, sometimes 0 for other - * uses, or the previous crc32/crc32c value if computing incrementally. - * @p: pointer to buffer over which CRC32/CRC32C is run - * @len: length of buffer @p - * @tab: little-endian Ethernet table - * @polynomial: CRC32/CRC32c LE polynomial - */ -static inline u32 __pure crc32_le_generic(u32 crc, unsigned char const *p, - size_t len, const u32 (*tab)[256], - u32 polynomial) -{ -#if CRC_LE_BITS == 1 - int i; - while (len--) { - crc ^= *p++; - for (i = 0; i < 8; i++) - crc = (crc >> 1) ^ ((crc & 1) ? polynomial : 0); - } -# elif CRC_LE_BITS == 2 - while (len--) { - crc ^= *p++; - crc = (crc >> 2) ^ tab[0][crc & 3]; - crc = (crc >> 2) ^ tab[0][crc & 3]; - crc = (crc >> 2) ^ tab[0][crc & 3]; - crc = (crc >> 2) ^ tab[0][crc & 3]; - } -# elif CRC_LE_BITS == 4 - while (len--) { - crc ^= *p++; - crc = (crc >> 4) ^ tab[0][crc & 15]; - crc = (crc >> 4) ^ tab[0][crc & 15]; - } -# elif CRC_LE_BITS == 8 - /* aka Sarwate algorithm */ - while (len--) { - crc ^= *p++; - crc = (crc >> 8) ^ tab[0][crc & 255]; - } -# else - crc = (__force u32) __cpu_to_le32(crc); - crc = crc32_body(crc, p, len, tab); - crc = __le32_to_cpu((__force __le32)crc); -#endif - return crc; -} - -#if CRC_LE_BITS == 1 -u32 __pure __weak crc32_le(u32 crc, unsigned char const *p, size_t len) -{ - return crc32_le_generic(crc, p, len, NULL, CRC32_POLY_LE); -} -u32 __pure __weak __crc32c_le(u32 crc, unsigned char const *p, size_t len) -{ - return crc32_le_generic(crc, p, len, NULL, CRC32C_POLY_LE); -} -#else -u32 __pure __weak crc32_le(u32 crc, unsigned char const *p, size_t len) -{ - return crc32_le_generic(crc, p, len, crc32table_le, CRC32_POLY_LE); -} -u32 __pure __weak __crc32c_le(u32 crc, unsigned char const *p, size_t len) -{ - return crc32_le_generic(crc, p, len, crc32ctable_le, CRC32C_POLY_LE); -} -#endif -EXPORT_SYMBOL(crc32_le); -EXPORT_SYMBOL(__crc32c_le); - -u32 __pure crc32_le_base(u32, unsigned char const *, size_t) __alias(crc32_le); -u32 __pure __crc32c_le_base(u32, unsigned char const *, size_t) __alias(__crc32c_le); -u32 __pure crc32_be_base(u32, unsigned char const *, size_t) __alias(crc32_be); - -/* - * This multiplies the polynomials x and y modulo the given modulus. - * This follows the "little-endian" CRC convention that the lsbit - * represents the highest power of x, and the msbit represents x^0. - */ -static u32 __attribute_const__ gf2_multiply(u32 x, u32 y, u32 modulus) -{ - u32 product = x & 1 ? y : 0; - int i; - - for (i = 0; i < 31; i++) { - product = (product >> 1) ^ (product & 1 ? modulus : 0); - x >>= 1; - product ^= x & 1 ? y : 0; - } - - return product; -} - -/** - * crc32_generic_shift - Append @len 0 bytes to crc, in logarithmic time - * @crc: The original little-endian CRC (i.e. lsbit is x^31 coefficient) - * @len: The number of bytes. @crc is multiplied by x^(8*@len) - * @polynomial: The modulus used to reduce the result to 32 bits. - * - * It's possible to parallelize CRC computations by computing a CRC - * over separate ranges of a buffer, then summing them. - * This shifts the given CRC by 8*len bits (i.e. produces the same effect - * as appending len bytes of zero to the data), in time proportional - * to log(len). - */ -static u32 __attribute_const__ crc32_generic_shift(u32 crc, size_t len, - u32 polynomial) -{ - u32 power = polynomial; /* CRC of x^32 */ - int i; - - /* Shift up to 32 bits in the simple linear way */ - for (i = 0; i < 8 * (int)(len & 3); i++) - crc = (crc >> 1) ^ (crc & 1 ? polynomial : 0); - - len >>= 2; - if (!len) - return crc; - - for (;;) { - /* "power" is x^(2^i), modulo the polynomial */ - if (len & 1) - crc = gf2_multiply(crc, power, polynomial); - - len >>= 1; - if (!len) - break; - - /* Square power, advancing to x^(2^(i+1)) */ - power = gf2_multiply(power, power, polynomial); - } - - return crc; -} - -u32 __attribute_const__ crc32_le_shift(u32 crc, size_t len) -{ - return crc32_generic_shift(crc, len, CRC32_POLY_LE); -} - -u32 __attribute_const__ __crc32c_le_shift(u32 crc, size_t len) -{ - return crc32_generic_shift(crc, len, CRC32C_POLY_LE); -} -EXPORT_SYMBOL(crc32_le_shift); -EXPORT_SYMBOL(__crc32c_le_shift); - -/** - * crc32_be_generic() - Calculate bitwise big-endian Ethernet AUTODIN II CRC32 - * @crc: seed value for computation. ~0 for Ethernet, sometimes 0 for - * other uses, or the previous crc32 value if computing incrementally. - * @p: pointer to buffer over which CRC32 is run - * @len: length of buffer @p - * @tab: big-endian Ethernet table - * @polynomial: CRC32 BE polynomial - */ -static inline u32 __pure crc32_be_generic(u32 crc, unsigned char const *p, - size_t len, const u32 (*tab)[256], - u32 polynomial) -{ -#if CRC_BE_BITS == 1 - int i; - while (len--) { - crc ^= *p++ << 24; - for (i = 0; i < 8; i++) - crc = - (crc << 1) ^ ((crc & 0x80000000) ? polynomial : - 0); - } -# elif CRC_BE_BITS == 2 - while (len--) { - crc ^= *p++ << 24; - crc = (crc << 2) ^ tab[0][crc >> 30]; - crc = (crc << 2) ^ tab[0][crc >> 30]; - crc = (crc << 2) ^ tab[0][crc >> 30]; - crc = (crc << 2) ^ tab[0][crc >> 30]; - } -# elif CRC_BE_BITS == 4 - while (len--) { - crc ^= *p++ << 24; - crc = (crc << 4) ^ tab[0][crc >> 28]; - crc = (crc << 4) ^ tab[0][crc >> 28]; - } -# elif CRC_BE_BITS == 8 - while (len--) { - crc ^= *p++ << 24; - crc = (crc << 8) ^ tab[0][crc >> 24]; - } -# else - crc = (__force u32) __cpu_to_be32(crc); - crc = crc32_body(crc, p, len, tab); - crc = __be32_to_cpu((__force __be32)crc); -# endif - return crc; -} - -#if CRC_BE_BITS == 1 -u32 __pure __weak crc32_be(u32 crc, unsigned char const *p, size_t len) -{ - return crc32_be_generic(crc, p, len, NULL, CRC32_POLY_BE); -} -#else -u32 __pure __weak crc32_be(u32 crc, unsigned char const *p, size_t len) -{ - return crc32_be_generic(crc, p, len, crc32table_be, CRC32_POLY_BE); -} -#endif -EXPORT_SYMBOL(crc32_be); |
