WSL2-Linux-Kernel/lib/gen_crc64table.c

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lib: add crc64 calculation routines Patch series "add crc64 calculation as kernel library", v5. This patchset adds basic implementation of crc64 calculation as a Linux kernel library. Since bcache already does crc64 by itself, this patchset also modifies bcache code to use the new crc64 library routine. Currently bcache is the only user of crc64 calculation, another potential user is bcachefs which is on the way to be in mainline kernel. Therefore it makes sense to make crc64 calculation to be a public library. bcache uses crc64 as storage checksum, if a change of crc lib routines results an inconsistent result, the unmatched checksum may make bcache 'think' the on-disk is corrupted, such a change should be avoided or detected as early as possible. Therefore a patch is being prepared which adds a crc test framework, to check consistency of different calculations. This patch (of 2): Add the re-write crc64 calculation routines for Linux kernel. The CRC64 polynomical arithmetic follows ECMA-182 specification, inspired by CRC paper of Dr. Ross N. Williams (see http://www.ross.net/crc/download/crc_v3.txt) and other public domain implementations. All the changes work in this way, - When Linux kernel is built, host program lib/gen_crc64table.c will be compiled to lib/gen_crc64table and executed. - The output of gen_crc64table execution is an array called as lookup table (a.k.a POLY 0x42f0e1eba9ea369) which contain 256 64-bit long numbers, this table is dumped into header file lib/crc64table.h. - Then the header file is included by lib/crc64.c for normal 64bit crc calculation. - Function declaration of the crc64 calculation routines is placed in include/linux/crc64.h Currently bcache is the only user of crc64_be(), another potential user is bcachefs which is on the way to be in mainline kernel. Therefore it makes sense to move crc64 calculation into lib/crc64.c as public code. [colyli@suse.de: fix review comments from v4] Link: http://lkml.kernel.org/r/20180726053352.2781-2-colyli@suse.de Link: http://lkml.kernel.org/r/20180718165545.1622-2-colyli@suse.de Signed-off-by: Coly Li <colyli@suse.de> Co-developed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Michael Lyle <mlyle@lyle.org> Cc: Kent Overstreet <kent.overstreet@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Kate Stewart <kstewart@linuxfoundation.org> Cc: Eric Biggers <ebiggers3@gmail.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Noah Massey <noah.massey@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-22 07:57:11 +03:00
// SPDX-License-Identifier: GPL-2.0
/*
* Generate lookup table for the table-driven CRC64 calculation.
*
* gen_crc64table is executed in kernel build time and generates
* lib/crc64table.h. This header is included by lib/crc64.c for
* the table-driven CRC64 calculation.
*
* See lib/crc64.c for more information about which specification
* and polynomial arithmetic that gen_crc64table.c follows to
* generate the lookup table.
*
* Copyright 2018 SUSE Linux.
* Author: Coly Li <colyli@suse.de>
*/
#include <inttypes.h>
#include <stdio.h>
#define CRC64_ECMA182_POLY 0x42F0E1EBA9EA3693ULL
#define CRC64_ROCKSOFT_POLY 0x9A6C9329AC4BC9B5ULL
lib: add crc64 calculation routines Patch series "add crc64 calculation as kernel library", v5. This patchset adds basic implementation of crc64 calculation as a Linux kernel library. Since bcache already does crc64 by itself, this patchset also modifies bcache code to use the new crc64 library routine. Currently bcache is the only user of crc64 calculation, another potential user is bcachefs which is on the way to be in mainline kernel. Therefore it makes sense to make crc64 calculation to be a public library. bcache uses crc64 as storage checksum, if a change of crc lib routines results an inconsistent result, the unmatched checksum may make bcache 'think' the on-disk is corrupted, such a change should be avoided or detected as early as possible. Therefore a patch is being prepared which adds a crc test framework, to check consistency of different calculations. This patch (of 2): Add the re-write crc64 calculation routines for Linux kernel. The CRC64 polynomical arithmetic follows ECMA-182 specification, inspired by CRC paper of Dr. Ross N. Williams (see http://www.ross.net/crc/download/crc_v3.txt) and other public domain implementations. All the changes work in this way, - When Linux kernel is built, host program lib/gen_crc64table.c will be compiled to lib/gen_crc64table and executed. - The output of gen_crc64table execution is an array called as lookup table (a.k.a POLY 0x42f0e1eba9ea369) which contain 256 64-bit long numbers, this table is dumped into header file lib/crc64table.h. - Then the header file is included by lib/crc64.c for normal 64bit crc calculation. - Function declaration of the crc64 calculation routines is placed in include/linux/crc64.h Currently bcache is the only user of crc64_be(), another potential user is bcachefs which is on the way to be in mainline kernel. Therefore it makes sense to move crc64 calculation into lib/crc64.c as public code. [colyli@suse.de: fix review comments from v4] Link: http://lkml.kernel.org/r/20180726053352.2781-2-colyli@suse.de Link: http://lkml.kernel.org/r/20180718165545.1622-2-colyli@suse.de Signed-off-by: Coly Li <colyli@suse.de> Co-developed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Michael Lyle <mlyle@lyle.org> Cc: Kent Overstreet <kent.overstreet@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Kate Stewart <kstewart@linuxfoundation.org> Cc: Eric Biggers <ebiggers3@gmail.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Noah Massey <noah.massey@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-22 07:57:11 +03:00
static uint64_t crc64_table[256] = {0};
static uint64_t crc64_rocksoft_table[256] = {0};
lib: add crc64 calculation routines Patch series "add crc64 calculation as kernel library", v5. This patchset adds basic implementation of crc64 calculation as a Linux kernel library. Since bcache already does crc64 by itself, this patchset also modifies bcache code to use the new crc64 library routine. Currently bcache is the only user of crc64 calculation, another potential user is bcachefs which is on the way to be in mainline kernel. Therefore it makes sense to make crc64 calculation to be a public library. bcache uses crc64 as storage checksum, if a change of crc lib routines results an inconsistent result, the unmatched checksum may make bcache 'think' the on-disk is corrupted, such a change should be avoided or detected as early as possible. Therefore a patch is being prepared which adds a crc test framework, to check consistency of different calculations. This patch (of 2): Add the re-write crc64 calculation routines for Linux kernel. The CRC64 polynomical arithmetic follows ECMA-182 specification, inspired by CRC paper of Dr. Ross N. Williams (see http://www.ross.net/crc/download/crc_v3.txt) and other public domain implementations. All the changes work in this way, - When Linux kernel is built, host program lib/gen_crc64table.c will be compiled to lib/gen_crc64table and executed. - The output of gen_crc64table execution is an array called as lookup table (a.k.a POLY 0x42f0e1eba9ea369) which contain 256 64-bit long numbers, this table is dumped into header file lib/crc64table.h. - Then the header file is included by lib/crc64.c for normal 64bit crc calculation. - Function declaration of the crc64 calculation routines is placed in include/linux/crc64.h Currently bcache is the only user of crc64_be(), another potential user is bcachefs which is on the way to be in mainline kernel. Therefore it makes sense to move crc64 calculation into lib/crc64.c as public code. [colyli@suse.de: fix review comments from v4] Link: http://lkml.kernel.org/r/20180726053352.2781-2-colyli@suse.de Link: http://lkml.kernel.org/r/20180718165545.1622-2-colyli@suse.de Signed-off-by: Coly Li <colyli@suse.de> Co-developed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Michael Lyle <mlyle@lyle.org> Cc: Kent Overstreet <kent.overstreet@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Kate Stewart <kstewart@linuxfoundation.org> Cc: Eric Biggers <ebiggers3@gmail.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Noah Massey <noah.massey@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-22 07:57:11 +03:00
static void generate_reflected_crc64_table(uint64_t table[256], uint64_t poly)
{
uint64_t i, j, c, crc;
for (i = 0; i < 256; i++) {
crc = 0ULL;
c = i;
for (j = 0; j < 8; j++) {
if ((crc ^ (c >> j)) & 1)
crc = (crc >> 1) ^ poly;
else
crc >>= 1;
}
table[i] = crc;
}
}
static void generate_crc64_table(uint64_t table[256], uint64_t poly)
lib: add crc64 calculation routines Patch series "add crc64 calculation as kernel library", v5. This patchset adds basic implementation of crc64 calculation as a Linux kernel library. Since bcache already does crc64 by itself, this patchset also modifies bcache code to use the new crc64 library routine. Currently bcache is the only user of crc64 calculation, another potential user is bcachefs which is on the way to be in mainline kernel. Therefore it makes sense to make crc64 calculation to be a public library. bcache uses crc64 as storage checksum, if a change of crc lib routines results an inconsistent result, the unmatched checksum may make bcache 'think' the on-disk is corrupted, such a change should be avoided or detected as early as possible. Therefore a patch is being prepared which adds a crc test framework, to check consistency of different calculations. This patch (of 2): Add the re-write crc64 calculation routines for Linux kernel. The CRC64 polynomical arithmetic follows ECMA-182 specification, inspired by CRC paper of Dr. Ross N. Williams (see http://www.ross.net/crc/download/crc_v3.txt) and other public domain implementations. All the changes work in this way, - When Linux kernel is built, host program lib/gen_crc64table.c will be compiled to lib/gen_crc64table and executed. - The output of gen_crc64table execution is an array called as lookup table (a.k.a POLY 0x42f0e1eba9ea369) which contain 256 64-bit long numbers, this table is dumped into header file lib/crc64table.h. - Then the header file is included by lib/crc64.c for normal 64bit crc calculation. - Function declaration of the crc64 calculation routines is placed in include/linux/crc64.h Currently bcache is the only user of crc64_be(), another potential user is bcachefs which is on the way to be in mainline kernel. Therefore it makes sense to move crc64 calculation into lib/crc64.c as public code. [colyli@suse.de: fix review comments from v4] Link: http://lkml.kernel.org/r/20180726053352.2781-2-colyli@suse.de Link: http://lkml.kernel.org/r/20180718165545.1622-2-colyli@suse.de Signed-off-by: Coly Li <colyli@suse.de> Co-developed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Michael Lyle <mlyle@lyle.org> Cc: Kent Overstreet <kent.overstreet@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Kate Stewart <kstewart@linuxfoundation.org> Cc: Eric Biggers <ebiggers3@gmail.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Noah Massey <noah.massey@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-22 07:57:11 +03:00
{
uint64_t i, j, c, crc;
for (i = 0; i < 256; i++) {
crc = 0;
c = i << 56;
for (j = 0; j < 8; j++) {
if ((crc ^ c) & 0x8000000000000000ULL)
crc = (crc << 1) ^ poly;
lib: add crc64 calculation routines Patch series "add crc64 calculation as kernel library", v5. This patchset adds basic implementation of crc64 calculation as a Linux kernel library. Since bcache already does crc64 by itself, this patchset also modifies bcache code to use the new crc64 library routine. Currently bcache is the only user of crc64 calculation, another potential user is bcachefs which is on the way to be in mainline kernel. Therefore it makes sense to make crc64 calculation to be a public library. bcache uses crc64 as storage checksum, if a change of crc lib routines results an inconsistent result, the unmatched checksum may make bcache 'think' the on-disk is corrupted, such a change should be avoided or detected as early as possible. Therefore a patch is being prepared which adds a crc test framework, to check consistency of different calculations. This patch (of 2): Add the re-write crc64 calculation routines for Linux kernel. The CRC64 polynomical arithmetic follows ECMA-182 specification, inspired by CRC paper of Dr. Ross N. Williams (see http://www.ross.net/crc/download/crc_v3.txt) and other public domain implementations. All the changes work in this way, - When Linux kernel is built, host program lib/gen_crc64table.c will be compiled to lib/gen_crc64table and executed. - The output of gen_crc64table execution is an array called as lookup table (a.k.a POLY 0x42f0e1eba9ea369) which contain 256 64-bit long numbers, this table is dumped into header file lib/crc64table.h. - Then the header file is included by lib/crc64.c for normal 64bit crc calculation. - Function declaration of the crc64 calculation routines is placed in include/linux/crc64.h Currently bcache is the only user of crc64_be(), another potential user is bcachefs which is on the way to be in mainline kernel. Therefore it makes sense to move crc64 calculation into lib/crc64.c as public code. [colyli@suse.de: fix review comments from v4] Link: http://lkml.kernel.org/r/20180726053352.2781-2-colyli@suse.de Link: http://lkml.kernel.org/r/20180718165545.1622-2-colyli@suse.de Signed-off-by: Coly Li <colyli@suse.de> Co-developed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Michael Lyle <mlyle@lyle.org> Cc: Kent Overstreet <kent.overstreet@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Kate Stewart <kstewart@linuxfoundation.org> Cc: Eric Biggers <ebiggers3@gmail.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Noah Massey <noah.massey@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-22 07:57:11 +03:00
else
crc <<= 1;
c <<= 1;
}
table[i] = crc;
lib: add crc64 calculation routines Patch series "add crc64 calculation as kernel library", v5. This patchset adds basic implementation of crc64 calculation as a Linux kernel library. Since bcache already does crc64 by itself, this patchset also modifies bcache code to use the new crc64 library routine. Currently bcache is the only user of crc64 calculation, another potential user is bcachefs which is on the way to be in mainline kernel. Therefore it makes sense to make crc64 calculation to be a public library. bcache uses crc64 as storage checksum, if a change of crc lib routines results an inconsistent result, the unmatched checksum may make bcache 'think' the on-disk is corrupted, such a change should be avoided or detected as early as possible. Therefore a patch is being prepared which adds a crc test framework, to check consistency of different calculations. This patch (of 2): Add the re-write crc64 calculation routines for Linux kernel. The CRC64 polynomical arithmetic follows ECMA-182 specification, inspired by CRC paper of Dr. Ross N. Williams (see http://www.ross.net/crc/download/crc_v3.txt) and other public domain implementations. All the changes work in this way, - When Linux kernel is built, host program lib/gen_crc64table.c will be compiled to lib/gen_crc64table and executed. - The output of gen_crc64table execution is an array called as lookup table (a.k.a POLY 0x42f0e1eba9ea369) which contain 256 64-bit long numbers, this table is dumped into header file lib/crc64table.h. - Then the header file is included by lib/crc64.c for normal 64bit crc calculation. - Function declaration of the crc64 calculation routines is placed in include/linux/crc64.h Currently bcache is the only user of crc64_be(), another potential user is bcachefs which is on the way to be in mainline kernel. Therefore it makes sense to move crc64 calculation into lib/crc64.c as public code. [colyli@suse.de: fix review comments from v4] Link: http://lkml.kernel.org/r/20180726053352.2781-2-colyli@suse.de Link: http://lkml.kernel.org/r/20180718165545.1622-2-colyli@suse.de Signed-off-by: Coly Li <colyli@suse.de> Co-developed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Michael Lyle <mlyle@lyle.org> Cc: Kent Overstreet <kent.overstreet@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Kate Stewart <kstewart@linuxfoundation.org> Cc: Eric Biggers <ebiggers3@gmail.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Noah Massey <noah.massey@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-22 07:57:11 +03:00
}
}
static void output_table(uint64_t table[256])
lib: add crc64 calculation routines Patch series "add crc64 calculation as kernel library", v5. This patchset adds basic implementation of crc64 calculation as a Linux kernel library. Since bcache already does crc64 by itself, this patchset also modifies bcache code to use the new crc64 library routine. Currently bcache is the only user of crc64 calculation, another potential user is bcachefs which is on the way to be in mainline kernel. Therefore it makes sense to make crc64 calculation to be a public library. bcache uses crc64 as storage checksum, if a change of crc lib routines results an inconsistent result, the unmatched checksum may make bcache 'think' the on-disk is corrupted, such a change should be avoided or detected as early as possible. Therefore a patch is being prepared which adds a crc test framework, to check consistency of different calculations. This patch (of 2): Add the re-write crc64 calculation routines for Linux kernel. The CRC64 polynomical arithmetic follows ECMA-182 specification, inspired by CRC paper of Dr. Ross N. Williams (see http://www.ross.net/crc/download/crc_v3.txt) and other public domain implementations. All the changes work in this way, - When Linux kernel is built, host program lib/gen_crc64table.c will be compiled to lib/gen_crc64table and executed. - The output of gen_crc64table execution is an array called as lookup table (a.k.a POLY 0x42f0e1eba9ea369) which contain 256 64-bit long numbers, this table is dumped into header file lib/crc64table.h. - Then the header file is included by lib/crc64.c for normal 64bit crc calculation. - Function declaration of the crc64 calculation routines is placed in include/linux/crc64.h Currently bcache is the only user of crc64_be(), another potential user is bcachefs which is on the way to be in mainline kernel. Therefore it makes sense to move crc64 calculation into lib/crc64.c as public code. [colyli@suse.de: fix review comments from v4] Link: http://lkml.kernel.org/r/20180726053352.2781-2-colyli@suse.de Link: http://lkml.kernel.org/r/20180718165545.1622-2-colyli@suse.de Signed-off-by: Coly Li <colyli@suse.de> Co-developed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Michael Lyle <mlyle@lyle.org> Cc: Kent Overstreet <kent.overstreet@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Kate Stewart <kstewart@linuxfoundation.org> Cc: Eric Biggers <ebiggers3@gmail.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Noah Massey <noah.massey@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-22 07:57:11 +03:00
{
int i;
for (i = 0; i < 256; i++) {
printf("\t0x%016" PRIx64 "ULL", table[i]);
lib: add crc64 calculation routines Patch series "add crc64 calculation as kernel library", v5. This patchset adds basic implementation of crc64 calculation as a Linux kernel library. Since bcache already does crc64 by itself, this patchset also modifies bcache code to use the new crc64 library routine. Currently bcache is the only user of crc64 calculation, another potential user is bcachefs which is on the way to be in mainline kernel. Therefore it makes sense to make crc64 calculation to be a public library. bcache uses crc64 as storage checksum, if a change of crc lib routines results an inconsistent result, the unmatched checksum may make bcache 'think' the on-disk is corrupted, such a change should be avoided or detected as early as possible. Therefore a patch is being prepared which adds a crc test framework, to check consistency of different calculations. This patch (of 2): Add the re-write crc64 calculation routines for Linux kernel. The CRC64 polynomical arithmetic follows ECMA-182 specification, inspired by CRC paper of Dr. Ross N. Williams (see http://www.ross.net/crc/download/crc_v3.txt) and other public domain implementations. All the changes work in this way, - When Linux kernel is built, host program lib/gen_crc64table.c will be compiled to lib/gen_crc64table and executed. - The output of gen_crc64table execution is an array called as lookup table (a.k.a POLY 0x42f0e1eba9ea369) which contain 256 64-bit long numbers, this table is dumped into header file lib/crc64table.h. - Then the header file is included by lib/crc64.c for normal 64bit crc calculation. - Function declaration of the crc64 calculation routines is placed in include/linux/crc64.h Currently bcache is the only user of crc64_be(), another potential user is bcachefs which is on the way to be in mainline kernel. Therefore it makes sense to move crc64 calculation into lib/crc64.c as public code. [colyli@suse.de: fix review comments from v4] Link: http://lkml.kernel.org/r/20180726053352.2781-2-colyli@suse.de Link: http://lkml.kernel.org/r/20180718165545.1622-2-colyli@suse.de Signed-off-by: Coly Li <colyli@suse.de> Co-developed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Michael Lyle <mlyle@lyle.org> Cc: Kent Overstreet <kent.overstreet@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Kate Stewart <kstewart@linuxfoundation.org> Cc: Eric Biggers <ebiggers3@gmail.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Noah Massey <noah.massey@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-22 07:57:11 +03:00
if (i & 0x1)
printf(",\n");
else
printf(", ");
}
printf("};\n");
}
static void print_crc64_tables(void)
{
printf("/* this file is generated - do not edit */\n\n");
printf("#include <linux/types.h>\n");
printf("#include <linux/cache.h>\n\n");
printf("static const u64 ____cacheline_aligned crc64table[256] = {\n");
output_table(crc64_table);
printf("\nstatic const u64 ____cacheline_aligned crc64rocksofttable[256] = {\n");
output_table(crc64_rocksoft_table);
}
lib: add crc64 calculation routines Patch series "add crc64 calculation as kernel library", v5. This patchset adds basic implementation of crc64 calculation as a Linux kernel library. Since bcache already does crc64 by itself, this patchset also modifies bcache code to use the new crc64 library routine. Currently bcache is the only user of crc64 calculation, another potential user is bcachefs which is on the way to be in mainline kernel. Therefore it makes sense to make crc64 calculation to be a public library. bcache uses crc64 as storage checksum, if a change of crc lib routines results an inconsistent result, the unmatched checksum may make bcache 'think' the on-disk is corrupted, such a change should be avoided or detected as early as possible. Therefore a patch is being prepared which adds a crc test framework, to check consistency of different calculations. This patch (of 2): Add the re-write crc64 calculation routines for Linux kernel. The CRC64 polynomical arithmetic follows ECMA-182 specification, inspired by CRC paper of Dr. Ross N. Williams (see http://www.ross.net/crc/download/crc_v3.txt) and other public domain implementations. All the changes work in this way, - When Linux kernel is built, host program lib/gen_crc64table.c will be compiled to lib/gen_crc64table and executed. - The output of gen_crc64table execution is an array called as lookup table (a.k.a POLY 0x42f0e1eba9ea369) which contain 256 64-bit long numbers, this table is dumped into header file lib/crc64table.h. - Then the header file is included by lib/crc64.c for normal 64bit crc calculation. - Function declaration of the crc64 calculation routines is placed in include/linux/crc64.h Currently bcache is the only user of crc64_be(), another potential user is bcachefs which is on the way to be in mainline kernel. Therefore it makes sense to move crc64 calculation into lib/crc64.c as public code. [colyli@suse.de: fix review comments from v4] Link: http://lkml.kernel.org/r/20180726053352.2781-2-colyli@suse.de Link: http://lkml.kernel.org/r/20180718165545.1622-2-colyli@suse.de Signed-off-by: Coly Li <colyli@suse.de> Co-developed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Michael Lyle <mlyle@lyle.org> Cc: Kent Overstreet <kent.overstreet@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Kate Stewart <kstewart@linuxfoundation.org> Cc: Eric Biggers <ebiggers3@gmail.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Noah Massey <noah.massey@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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int main(int argc, char *argv[])
{
generate_crc64_table(crc64_table, CRC64_ECMA182_POLY);
generate_reflected_crc64_table(crc64_rocksoft_table, CRC64_ROCKSOFT_POLY);
print_crc64_tables();
lib: add crc64 calculation routines Patch series "add crc64 calculation as kernel library", v5. This patchset adds basic implementation of crc64 calculation as a Linux kernel library. Since bcache already does crc64 by itself, this patchset also modifies bcache code to use the new crc64 library routine. Currently bcache is the only user of crc64 calculation, another potential user is bcachefs which is on the way to be in mainline kernel. Therefore it makes sense to make crc64 calculation to be a public library. bcache uses crc64 as storage checksum, if a change of crc lib routines results an inconsistent result, the unmatched checksum may make bcache 'think' the on-disk is corrupted, such a change should be avoided or detected as early as possible. Therefore a patch is being prepared which adds a crc test framework, to check consistency of different calculations. This patch (of 2): Add the re-write crc64 calculation routines for Linux kernel. The CRC64 polynomical arithmetic follows ECMA-182 specification, inspired by CRC paper of Dr. Ross N. Williams (see http://www.ross.net/crc/download/crc_v3.txt) and other public domain implementations. All the changes work in this way, - When Linux kernel is built, host program lib/gen_crc64table.c will be compiled to lib/gen_crc64table and executed. - The output of gen_crc64table execution is an array called as lookup table (a.k.a POLY 0x42f0e1eba9ea369) which contain 256 64-bit long numbers, this table is dumped into header file lib/crc64table.h. - Then the header file is included by lib/crc64.c for normal 64bit crc calculation. - Function declaration of the crc64 calculation routines is placed in include/linux/crc64.h Currently bcache is the only user of crc64_be(), another potential user is bcachefs which is on the way to be in mainline kernel. Therefore it makes sense to move crc64 calculation into lib/crc64.c as public code. [colyli@suse.de: fix review comments from v4] Link: http://lkml.kernel.org/r/20180726053352.2781-2-colyli@suse.de Link: http://lkml.kernel.org/r/20180718165545.1622-2-colyli@suse.de Signed-off-by: Coly Li <colyli@suse.de> Co-developed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Michael Lyle <mlyle@lyle.org> Cc: Kent Overstreet <kent.overstreet@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Kate Stewart <kstewart@linuxfoundation.org> Cc: Eric Biggers <ebiggers3@gmail.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Noah Massey <noah.massey@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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return 0;
}