Commit 46c5801e authored by Darrick J. Wong's avatar Darrick J. Wong Committed by Linus Torvalds
Browse files

crc32: bolt on crc32c 



Reuse the existing crc32 code to stamp out a crc32c implementation.

Signed-off-by: default avatarDarrick J. Wong <djwong@us.ibm.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Bob Pearson <rpearson@systemfabricworks.com>
Cc: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 78dff418

include/linux/crc32.h

+2 −0
Original line number Diff line number Diff line
@@ -11,6 +11,8 @@ 
extern u32  crc32_le(u32 crc, unsigned char const *p, size_t len);

extern u32  crc32_be(u32 crc, unsigned char const *p, size_t len);



extern u32  __crc32c_le(u32 crc, unsigned char const *p, size_t len);



#define crc32(seed, data, length)  crc32_le(seed, (unsigned char const *)(data), length)



/*

lib/Kconfig

+4 −4
Original line number Diff line number Diff line
@@ -61,14 +61,14 @@ config CRC_ITU_T 
	  functions require M here.



config CRC32

	tristate "CRC32 functions"

	tristate "CRC32/CRC32c functions"

	default y

	select BITREVERSE

	help

	  This option is provided for the case where no in-kernel-tree

	  modules require CRC32 functions, but a module built outside the

	  kernel tree does. Such modules that use library CRC32 functions

	  require M here.

	  modules require CRC32/CRC32c functions, but a module built outside

	  the kernel tree does. Such modules that use library CRC32/CRC32c

	  functions require M here.



config CRC32_SELFTEST

	bool "CRC32 perform self test on init"

lib/crc32.c

+56 −23
Original line number Diff line number Diff line
@@ -46,7 +46,7 @@ 
#include "crc32table.h"



MODULE_AUTHOR("Matt Domsch <Matt_Domsch@dell.com>");

MODULE_DESCRIPTION("Ethernet CRC32 calculations");

MODULE_DESCRIPTION("Various CRC32 calculations");

MODULE_LICENSE("GPL");



#if CRC_LE_BITS > 8 || CRC_BE_BITS > 8
@@ -135,45 +135,66 @@ crc32_body(u32 crc, unsigned char const *buf, size_t len, const u32 (*tab)[256]) 
 * @p: pointer to buffer over which CRC is run

 * @len: length of buffer @p

 */

u32 __pure crc32_le(u32 crc, unsigned char const *p, size_t len)

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) ? CRCPOLY_LE : 0);

			crc = (crc >> 1) ^ ((crc & 1) ? polynomial : 0);

	}

# elif CRC_LE_BITS == 2

	while (len--) {

		crc ^= *p++;

		crc = (crc >> 2) ^ crc32table_le[0][crc & 3];

		crc = (crc >> 2) ^ crc32table_le[0][crc & 3];

		crc = (crc >> 2) ^ crc32table_le[0][crc & 3];

		crc = (crc >> 2) ^ crc32table_le[0][crc & 3];

		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) ^ crc32table_le[0][crc & 15];

		crc = (crc >> 4) ^ crc32table_le[0][crc & 15];

		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) ^ crc32table_le[0][crc & 255];

		crc = (crc >> 8) ^ tab[0][crc & 255];

	}

# else

	const u32      (*tab)[] = crc32table_le;



	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 crc32_le(u32 crc, unsigned char const *p, size_t len)

{

	return crc32_le_generic(crc, p, len, NULL, CRCPOLY_LE);

}

u32 __pure __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 crc32_le(u32 crc, unsigned char const *p, size_t len)

{

	return crc32_le_generic(crc, p, len, crc32table_le, CRCPOLY_LE);

}

u32 __pure __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);



/**

 * crc32_be() - Calculate bitwise big-endian Ethernet AUTODIN II CRC32
@@ -182,7 +203,9 @@ EXPORT_SYMBOL(crc32_le); 
 * @p: pointer to buffer over which CRC is run

 * @len: length of buffer @p

 */

u32 __pure crc32_be(u32 crc, unsigned char const *p, size_t len)

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;
@@ -190,37 +213,47 @@ u32 __pure crc32_be(u32 crc, unsigned char const *p, size_t len) 
		crc ^= *p++ << 24;

		for (i = 0; i < 8; i++)

			crc =

			    (crc << 1) ^ ((crc & 0x80000000) ? CRCPOLY_BE :

			    (crc << 1) ^ ((crc & 0x80000000) ? polynomial :

					  0);

	}

# elif CRC_BE_BITS == 2

	while (len--) {

		crc ^= *p++ << 24;

		crc = (crc << 2) ^ crc32table_be[0][crc >> 30];

		crc = (crc << 2) ^ crc32table_be[0][crc >> 30];

		crc = (crc << 2) ^ crc32table_be[0][crc >> 30];

		crc = (crc << 2) ^ crc32table_be[0][crc >> 30];

		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) ^ crc32table_be[0][crc >> 28];

		crc = (crc << 4) ^ crc32table_be[0][crc >> 28];

		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) ^ crc32table_be[0][crc >> 24];

		crc = (crc << 8) ^ tab[0][crc >> 24];

	}

# else

	const u32      (*tab)[] = crc32table_be;



	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_LE_BITS == 1

u32 __pure crc32_be(u32 crc, unsigned char const *p, size_t len)

{

	return crc32_be_generic(crc, p, len, NULL, CRCPOLY_BE);

}

#else

u32 __pure crc32_be(u32 crc, unsigned char const *p, size_t len)

{

	return crc32_be_generic(crc, p, len, crc32table_be, CRCPOLY_BE);

}

#endif

EXPORT_SYMBOL(crc32_be);



#ifdef CONFIG_CRC32_SELFTEST

lib/crc32defs.h

+7 −0
Original line number Diff line number Diff line
@@ -6,6 +6,13 @@ 
#define CRCPOLY_LE 0xedb88320

#define CRCPOLY_BE 0x04c11db7



/*

 * This is the CRC32c polynomial, as outlined by Castagnoli.

 * x^32+x^28+x^27+x^26+x^25+x^23+x^22+x^20+x^19+x^18+x^14+x^13+x^11+x^10+x^9+

 * x^8+x^6+x^0

 */

#define CRC32C_POLY_LE 0x82F63B78



/*

 * How many bits at a time to use.  Valid values are 1, 2, 4, 8, 32 and 64.

 * For less performance-sensitive, use 4 or 8 to save table size.

lib/gen_crc32table.c

+28 −7
Original line number Diff line number Diff line
@@ -23,6 +23,7 @@ 


static uint32_t crc32table_le[LE_TABLE_ROWS][256];

static uint32_t crc32table_be[BE_TABLE_ROWS][256];

static uint32_t crc32ctable_le[LE_TABLE_ROWS][256];



/**

 * crc32init_le() - allocate and initialize LE table data
@@ -31,25 +32,36 @@ static uint32_t crc32table_be[BE_TABLE_ROWS][256]; 
 * fact that crctable[i^j] = crctable[i] ^ crctable[j].

 *

 */

static void crc32init_le(void)

static void crc32init_le_generic(const uint32_t polynomial,

				 uint32_t (*tab)[256])

{

	unsigned i, j;

	uint32_t crc = 1;



	crc32table_le[0][0] = 0;

	tab[0][0] = 0;



	for (i = LE_TABLE_SIZE >> 1; i; i >>= 1) {

		crc = (crc >> 1) ^ ((crc & 1) ? CRCPOLY_LE : 0);

		crc = (crc >> 1) ^ ((crc & 1) ? polynomial : 0);

		for (j = 0; j < LE_TABLE_SIZE; j += 2 * i)

			crc32table_le[0][i + j] = crc ^ crc32table_le[0][j];

			tab[0][i + j] = crc ^ tab[0][j];

	}

	for (i = 0; i < LE_TABLE_SIZE; i++) {

		crc = crc32table_le[0][i];

		crc = tab[0][i];

		for (j = 1; j < LE_TABLE_ROWS; j++) {

			crc = crc32table_le[0][crc & 0xff] ^ (crc >> 8);

			crc32table_le[j][i] = crc;

			crc = tab[0][crc & 0xff] ^ (crc >> 8);

			tab[j][i] = crc;

		}

	}

}



static void crc32init_le(void)

{

	crc32init_le_generic(CRCPOLY_LE, crc32table_le);

}



static void crc32cinit_le(void)

{

	crc32init_le_generic(CRC32C_POLY_LE, crc32ctable_le);

}



/**
@@ -114,6 +126,15 @@ int main(int argc, char** argv) 
			     BE_TABLE_SIZE, "tobe");

		printf("};\n");

	}

	if (CRC_LE_BITS > 1) {

		crc32cinit_le();

		printf("static const u32 __cacheline_aligned "

		       "crc32ctable_le[%d][%d] = {",

		       LE_TABLE_ROWS, LE_TABLE_SIZE);

		output_table(crc32ctable_le, LE_TABLE_ROWS,

			     LE_TABLE_SIZE, "tole");

		printf("};\n");

	}



	return 0;

}

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