cregit-Linux how code gets into the kernel

Release 4.13 lib/gen_crc32table.c

Directory: lib
#include <stdio.h>
#include "../include/generated/autoconf.h"
#include "crc32defs.h"
#include <inttypes.h>


#define ENTRIES_PER_LINE 4

#if CRC_LE_BITS > 8

# define LE_TABLE_ROWS (CRC_LE_BITS/8)

# define LE_TABLE_SIZE 256
#else

# define LE_TABLE_ROWS 1

# define LE_TABLE_SIZE (1 << CRC_LE_BITS)
#endif

#if CRC_BE_BITS > 8

# define BE_TABLE_ROWS (CRC_BE_BITS/8)

# define BE_TABLE_SIZE 256
#else

# define BE_TABLE_ROWS 1

# define BE_TABLE_SIZE (1 << CRC_BE_BITS)
#endif


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
 *
 * crc is the crc of the byte i; other entries are filled in based on the
 * fact that crctable[i^j] = crctable[i] ^ crctable[j].
 *
 */

static void crc32init_le_generic(const uint32_t polynomial,
				 uint32_t (*tab)[256])
{
	unsigned i, j;
	uint32_t crc = 1;

	tab[0][0] = 0;

	for (i = LE_TABLE_SIZE >> 1; i; i >>= 1) {
		crc = (crc >> 1) ^ ((crc & 1) ? polynomial : 0);
		for (j = 0; j < LE_TABLE_SIZE; j += 2 * i)
			tab[0][i + j] = crc ^ tab[0][j];
	}
	for (i = 0; i < LE_TABLE_SIZE; i++) {
		crc = tab[0][i];
		for (j = 1; j < LE_TABLE_ROWS; j++) {
			crc = tab[0][crc & 0xff] ^ (crc >> 8);
			tab[j][i] = crc;
		}
	}
}


static void crc32init_le(void) { crc32init_le_generic(CRCPOLY_LE, crc32table_le); }

Contributors

PersonTokensPropCommitsCommitProp
Darrick J. Wong15100.00%1100.00%
Total15100.00%1100.00%


static void crc32cinit_le(void) { crc32init_le_generic(CRC32C_POLY_LE, crc32ctable_le); }

Contributors

PersonTokensPropCommitsCommitProp
Darrick J. Wong15100.00%1100.00%
Total15100.00%1100.00%

/** * crc32init_be() - allocate and initialize BE table data */
static void crc32init_be(void) { unsigned i, j; uint32_t crc = 0x80000000; crc32table_be[0][0] = 0; for (i = 1; i < BE_TABLE_SIZE; i <<= 1) { crc = (crc << 1) ^ ((crc & 0x80000000) ? CRCPOLY_BE : 0); for (j = 0; j < i; j++) crc32table_be[0][i + j] = crc ^ crc32table_be[0][j]; } for (i = 0; i < BE_TABLE_SIZE; i++) { crc = crc32table_be[0][i]; for (j = 1; j < BE_TABLE_ROWS; j++) { crc = crc32table_be[0][(crc >> 24) & 0xff] ^ (crc << 8); crc32table_be[j][i] = crc; } } }

Contributors

PersonTokensPropCommitsCommitProp
Brian Murphy8751.48%125.00%
Joakim Tjernlund8047.34%125.00%
Bob Pearson10.59%125.00%
Andrew Morton10.59%125.00%
Total169100.00%4100.00%

static void output_table(uint32_t (*table)[256], int rows, int len, char *trans) { int i, j; for (j = 0 ; j < rows; j++) { printf("{"); for (i = 0; i < len - 1; i++) { if (i % ENTRIES_PER_LINE == 0) printf("\n"); printf("%s(0x%8.8xL), ", trans, table[j][i]); } printf("%s(0x%8.8xL)},\n", trans, table[j][len - 1]); } }
int main(int argc, char** argv) { printf("/* this file is generated - do not edit */\n\n"); if (CRC_LE_BITS > 1) { crc32init_le(); printf("static const u32 ____cacheline_aligned " "crc32table_le[%d][%d] = {", LE_TABLE_ROWS, LE_TABLE_SIZE); output_table(crc32table_le, LE_TABLE_ROWS, LE_TABLE_SIZE, "tole"); printf("};\n"); } if (CRC_BE_BITS > 1) { crc32init_be(); printf("static const u32 ____cacheline_aligned " "crc32table_be[%d][%d] = {", BE_TABLE_ROWS, BE_TABLE_SIZE); output_table(crc32table_be, LE_TABLE_ROWS, 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; }

Contributors

PersonTokensPropCommitsCommitProp
Brian Murphy7959.85%125.00%
Darrick J. Wong3627.27%125.00%
Bob Pearson1410.61%125.00%
Daniel Borkmann32.27%125.00%
Total132100.00%4100.00%


Overall Contributors

PersonTokensPropCommitsCommitProp
Brian Murphy34447.78%112.50%
Joakim Tjernlund18826.11%112.50%
Darrick J. Wong9813.61%112.50%
Bob Pearson8111.25%337.50%
Andrew Morton60.83%112.50%
Daniel Borkmann30.42%112.50%
Total720100.00%8100.00%
Directory: lib
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