1 files changed, 132 insertions, 0 deletions

diff --git a/lib/raid6/mktables.c b/lib/raid6/mktables.c
new file mode 100644
index 000000000000..3b1500843bba
--- /dev/null
+++ b/lib/raid6/mktables.c
@@ -0,0 +1,132 @@
+/* -*- 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");
+
+        /* 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 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;
+}