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author | Linus Torvalds <torvalds@linux-foundation.org> | 2018-08-22 12:34:08 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-08-22 12:34:08 -0700 |
commit | cd9b44f90763c3367e8dd0601849ffb028e8ba52 (patch) | |
tree | d1da0c2d49e3622fe51584a154ab383b3e783c1b /lib/gen_crc64table.c | |
parent | df2def49c57b4146520a1f4ca37bc3f494e2cd67 (diff) | |
parent | 2a9d6481004215da8e93edb588cf448f2af80303 (diff) | |
download | linux-cd9b44f90763c3367e8dd0601849ffb028e8ba52.tar.bz2 |
Merge branch 'akpm' (patches from Andrew)
Merge more updates from Andrew Morton:
- the rest of MM
- procfs updates
- various misc things
- more y2038 fixes
- get_maintainer updates
- lib/ updates
- checkpatch updates
- various epoll updates
- autofs updates
- hfsplus
- some reiserfs work
- fatfs updates
- signal.c cleanups
- ipc/ updates
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (166 commits)
ipc/util.c: update return value of ipc_getref from int to bool
ipc/util.c: further variable name cleanups
ipc: simplify ipc initialization
ipc: get rid of ids->tables_initialized hack
lib/rhashtable: guarantee initial hashtable allocation
lib/rhashtable: simplify bucket_table_alloc()
ipc: drop ipc_lock()
ipc/util.c: correct comment in ipc_obtain_object_check
ipc: rename ipcctl_pre_down_nolock()
ipc/util.c: use ipc_rcu_putref() for failues in ipc_addid()
ipc: reorganize initialization of kern_ipc_perm.seq
ipc: compute kern_ipc_perm.id under the ipc lock
init/Kconfig: remove EXPERT from CHECKPOINT_RESTORE
fs/sysv/inode.c: use ktime_get_real_seconds() for superblock stamp
adfs: use timespec64 for time conversion
kernel/sysctl.c: fix typos in comments
drivers/rapidio/devices/rio_mport_cdev.c: remove redundant pointer md
fork: don't copy inconsistent signal handler state to child
signal: make get_signal() return bool
signal: make sigkill_pending() return bool
...
Diffstat (limited to 'lib/gen_crc64table.c')
-rw-r--r-- | lib/gen_crc64table.c | 68 |
1 files changed, 68 insertions, 0 deletions
diff --git a/lib/gen_crc64table.c b/lib/gen_crc64table.c new file mode 100644 index 000000000000..9011926e4162 --- /dev/null +++ b/lib/gen_crc64table.c @@ -0,0 +1,68 @@ +// 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> + +#include <linux/swab.h> + +#define CRC64_ECMA182_POLY 0x42F0E1EBA9EA3693ULL + +static uint64_t crc64_table[256] = {0}; + +static void generate_crc64_table(void) +{ + 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) ^ CRC64_ECMA182_POLY; + else + crc <<= 1; + c <<= 1; + } + + crc64_table[i] = crc; + } +} + +static void print_crc64_table(void) +{ + int i; + + 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"); + for (i = 0; i < 256; i++) { + printf("\t0x%016" PRIx64 "ULL", crc64_table[i]); + if (i & 0x1) + printf(",\n"); + else + printf(", "); + } + printf("};\n"); +} + +int main(int argc, char *argv[]) +{ + generate_crc64_table(); + print_crc64_table(); + return 0; +} |