kbuild: filter away debug symbols from kernel symbols

Andi Kleen <andi@firstfloor.org>
reported that he saw a lot of symbols like this:

0000000000000b24 N DW.aio.h.903a6d92.2
0000000000000bce N DW.task_io_accounting.h.8d8de327.0
0000000000000bec N DW.hrtimer.h.c23659c6.0

in his System.map / kallsyms output.

Simple solution is to skip all debugging
symbols (they are marked 'N').

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Paulo Marques <pmarques@grupopie.com>

scripts/kallsyms.c

@@ -108,6 +108,9 @@ static int read_symbol(FILE *in, struct sym_entry *s)
 	/* exclude also MIPS ELF local symbols ($L123 instead of .L123) */
 	else if (str[0] == '$')
 		return -1;
+	/* exclude debugging symbols */
+	else if (stype == 'N')
+		return -1;
 
 	/* include the type field in the symbol name, so that it gets
 	 * compressed together */