diff options
Diffstat (limited to 'lib/raid6/mktables.c')
| -rw-r--r-- | lib/raid6/mktables.c | 158 |
1 files changed, 158 insertions, 0 deletions
diff --git a/lib/raid6/mktables.c b/lib/raid6/mktables.c new file mode 100644 index 000000000..39787db58 --- /dev/null +++ b/lib/raid6/mktables.c @@ -0,0 +1,158 @@ +/* -*- linux-c -*- ------------------------------------------------------- * + * + * Copyright 2002-2007 H. Peter Anvin - All Rights Reserved + * + * This file is part of the Linux kernel, and is made available under + * the terms of the GNU General Public License version 2 or (at your + * option) any later version; incorporated herein by reference. + * + * ----------------------------------------------------------------------- */ + +/* + * mktables.c + * + * Make RAID-6 tables. This is a host user space program to be run at + * compile time. + */ + +#include <stdio.h> +#include <string.h> +#include <inttypes.h> +#include <stdlib.h> +#include <time.h> + +static uint8_t gfmul(uint8_t a, uint8_t b) +{ + uint8_t v = 0; + + while (b) { + if (b & 1) + v ^= a; + a = (a << 1) ^ (a & 0x80 ? 0x1d : 0); + b >>= 1; + } + + return v; +} + +static uint8_t gfpow(uint8_t a, int b) +{ + uint8_t v = 1; + + b %= 255; + if (b < 0) + b += 255; + + while (b) { + if (b & 1) + v = gfmul(v, a); + a = gfmul(a, a); + b >>= 1; + } + + return v; +} + +int main(int argc, char *argv[]) +{ + int i, j, k; + uint8_t v; + uint8_t exptbl[256], invtbl[256]; + + printf("#include <linux/raid/pq.h>\n"); + printf("#include <linux/export.h>\n"); + + /* Compute multiplication table */ + printf("\nconst u8 __attribute__((aligned(256)))\n" + "raid6_gfmul[256][256] =\n" + "{\n"); + for (i = 0; i < 256; i++) { + printf("\t{\n"); + for (j = 0; j < 256; j += 8) { + printf("\t\t"); + for (k = 0; k < 8; k++) + printf("0x%02x,%c", gfmul(i, j + k), + (k == 7) ? '\n' : ' '); + } + printf("\t},\n"); + } + printf("};\n"); + printf("#ifdef __KERNEL__\n"); + printf("EXPORT_SYMBOL(raid6_gfmul);\n"); + printf("#endif\n"); + + /* Compute vector multiplication table */ + printf("\nconst u8 __attribute__((aligned(256)))\n" + "raid6_vgfmul[256][32] =\n" + "{\n"); + for (i = 0; i < 256; i++) { + printf("\t{\n"); + for (j = 0; j < 16; j += 8) { + printf("\t\t"); + for (k = 0; k < 8; k++) + printf("0x%02x,%c", gfmul(i, j + k), + (k == 7) ? '\n' : ' '); + } + for (j = 0; j < 16; j += 8) { + printf("\t\t"); + for (k = 0; k < 8; k++) + printf("0x%02x,%c", gfmul(i, (j + k) << 4), + (k == 7) ? '\n' : ' '); + } + printf("\t},\n"); + } + printf("};\n"); + printf("#ifdef __KERNEL__\n"); + printf("EXPORT_SYMBOL(raid6_vgfmul);\n"); + printf("#endif\n"); + + /* Compute power-of-2 table (exponent) */ + v = 1; + printf("\nconst u8 __attribute__((aligned(256)))\n" + "raid6_gfexp[256] =\n" "{\n"); + for (i = 0; i < 256; i += 8) { + printf("\t"); + for (j = 0; j < 8; j++) { + exptbl[i + j] = v; + printf("0x%02x,%c", v, (j == 7) ? '\n' : ' '); + v = gfmul(v, 2); + if (v == 1) + v = 0; /* For entry 255, not a real entry */ + } + } + printf("};\n"); + printf("#ifdef __KERNEL__\n"); + printf("EXPORT_SYMBOL(raid6_gfexp);\n"); + printf("#endif\n"); + + /* Compute inverse table x^-1 == x^254 */ + printf("\nconst u8 __attribute__((aligned(256)))\n" + "raid6_gfinv[256] =\n" "{\n"); + for (i = 0; i < 256; i += 8) { + printf("\t"); + for (j = 0; j < 8; j++) { + invtbl[i + j] = v = gfpow(i + j, 254); + printf("0x%02x,%c", v, (j == 7) ? '\n' : ' '); + } + } + printf("};\n"); + printf("#ifdef __KERNEL__\n"); + printf("EXPORT_SYMBOL(raid6_gfinv);\n"); + printf("#endif\n"); + + /* Compute inv(2^x + 1) (exponent-xor-inverse) table */ + printf("\nconst u8 __attribute__((aligned(256)))\n" + "raid6_gfexi[256] =\n" "{\n"); + for (i = 0; i < 256; i += 8) { + printf("\t"); + for (j = 0; j < 8; j++) + printf("0x%02x,%c", invtbl[exptbl[i + j] ^ 1], + (j == 7) ? '\n' : ' '); + } + printf("};\n"); + printf("#ifdef __KERNEL__\n"); + printf("EXPORT_SYMBOL(raid6_gfexi);\n"); + printf("#endif\n"); + + return 0; +} |