__attribute__((used)) provokes an error : 'used' attribute ignored

[Drasko DRASKOVIC <drasko.draskovic@xxxxxxxxx>]

Hi all,
I wanted to prevent compiler from optimizing out several variables of
Linux kerenel, so I can debug it in GDB, so I used
__attribute__((used))  following this philosophy :
http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0491c/BABCJJID.html

However, trying to compile my kernel, I am getting the error :
arch/mips/mm/tlb-r4k.c:73: error: 'used' attribute ignored

Why is this happening ?

Compiler version :
Target: mips-openwrt-linux-uclibc
gcc version 4.3.3 (GCC)


BR,
Drasko