1 files changed, 142 insertions, 0 deletions
diff --git a/lib/gen_crc32table.c b/lib/gen_crc32table.c
new file mode 100644
index 0000000000..f755b997b9
--- /dev/null
+++ b/lib/gen_crc32table.c
@@ -0,0 +1,142 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <stdio.h>
+#include "../include/linux/crc32poly.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(CRC32_POLY_LE, crc32table_le);
+}
+
+static void crc32cinit_le(void)
+{
+	crc32init_le_generic(CRC32C_POLY_LE, crc32ctable_le);
+}
+
+/**
+ * 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) ? CRC32_POLY_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;
+		}
+	}
+}
+
+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;
+}