unicode: constify utf8 data table

All users already handle the table as const data.
Move the table itself into .rodata to guard against accidental or
malicious modifications.

Signed-off-by: Thomas Weißschuh <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Gabriel Krisman Bertazi <[email protected]>

Author: t-8ch

fs/unicode/mkutf8data.c

@@ -3338,7 +3338,7 @@ static void write_file(void)
 	}
 	fprintf(file, "};\n");
 	fprintf(file, "\n");
-	fprintf(file, "struct utf8data_table utf8_data_table = {\n");
+	fprintf(file, "const struct utf8data_table utf8_data_table = {\n");
 	fprintf(file, "\t.utf8agetab = utf8agetab,\n");
 	fprintf(file, "\t.utf8agetab_size = ARRAY_SIZE(utf8agetab),\n");
 	fprintf(file, "\n");

fs/unicode/utf8data.c_shipped

@@ -4107,7 +4107,7 @@ static const unsigned char utf8data[64256] = {
 	0x81,0x80,0xcf,0x86,0x85,0x84,0xcf,0x86,0xcf,0x06,0x02,0x00,0x00,0x00,0x00,0x00
 };
 
-struct utf8data_table utf8_data_table = {
+const struct utf8data_table utf8_data_table = {
 	.utf8agetab = utf8agetab,
 	.utf8agetab_size = ARRAY_SIZE(utf8agetab),
 

fs/unicode/utf8n.h

@@ -78,6 +78,6 @@ struct utf8data_table {
 	const unsigned char *utf8data;
 };
 
-extern struct utf8data_table utf8_data_table;
+extern const struct utf8data_table utf8_data_table;
 
 #endif /* UTF8NORM_H */