diff --git a/fs/nls/nls_base.c b/fs/nls/nls_base.c
index 7dfdab9..e790581 100644
--- a/fs/nls/nls_base.c
+++ b/fs/nls/nls_base.c
@@ -34,7 +34,7 @@
 	long    lval;
 };
 
-static struct utf8_table utf8_table[] =
+static const struct utf8_table utf8_table[] =
 {
     {0x80,  0x00,   0*6,    0x7F,           0,         /* 1 byte sequence */},
     {0xE0,  0xC0,   1*6,    0x7FF,          0x80,      /* 2 byte sequence */},
@@ -50,7 +50,7 @@
 {
 	long l;
 	int c0, c, nc;
-	struct utf8_table *t;
+	const struct utf8_table *t;
   
 	nc = 0;
 	c0 = *s;
@@ -109,7 +109,7 @@
 {
 	long l;
 	int c, nc;
-	struct utf8_table *t;
+	const struct utf8_table *t;
   
 	if (s == 0)
 		return 0;
@@ -240,7 +240,7 @@
 	module_put(nls->owner);
 }
 
-static wchar_t charset2uni[256] = {
+static const wchar_t charset2uni[256] = {
 	/* 0x00*/
 	0x0000, 0x0001, 0x0002, 0x0003,
 	0x0004, 0x0005, 0x0006, 0x0007,
@@ -323,7 +323,7 @@
 	0x00fc, 0x00fd, 0x00fe, 0x00ff,
 };
 
-static unsigned char page00[256] = {
+static const unsigned char page00[256] = {
 	0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, /* 0x00-0x07 */
 	0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, /* 0x08-0x0f */
 	0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, /* 0x10-0x17 */
@@ -359,11 +359,11 @@
 	0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff, /* 0xf8-0xff */
 };
 
-static unsigned char *page_uni2charset[256] = {
+static const unsigned char *const page_uni2charset[256] = {
 	page00
 };
 
-static unsigned char charset2lower[256] = {
+static const unsigned char charset2lower[256] = {
 	0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, /* 0x00-0x07 */
 	0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, /* 0x08-0x0f */
 	0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, /* 0x10-0x17 */
@@ -399,7 +399,7 @@
 	0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff, /* 0xf8-0xff */
 };
 
-static unsigned char charset2upper[256] = {
+static const unsigned char charset2upper[256] = {
 	0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, /* 0x00-0x07 */
 	0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, /* 0x08-0x0f */
 	0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, /* 0x10-0x17 */
@@ -438,7 +438,7 @@
 
 static int uni2char(wchar_t uni, unsigned char *out, int boundlen)
 {
-	unsigned char *uni2charset;
+	const unsigned char *uni2charset;
 	unsigned char cl = uni & 0x00ff;
 	unsigned char ch = (uni & 0xff00) >> 8;