powerpc: don't fortify prom_init

prom_init is a bit special; in theory it should be able to be linked
separately to the kernel.  To keep this from getting too complex, the
symbols that prom_init.c uses are checked.

Fortification adds symbols, and it gets quite messy as it includes
things like panic().  So just don't fortify prom_init.c for now.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Daniel Axtens <[email protected]>
Signed-off-by: Kees Cook <[email protected]>
Acked-by: Michael Ellerman <[email protected]>
Cc: Daniel Micay <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

Author: daxtens

arch/powerpc/kernel/prom_init.c

@@ -15,6 +15,9 @@
 
 #undef DEBUG_PROM
 
+/* we cannot use FORTIFY as it brings in new symbols */
+#define __NO_FORTIFY
+
 #include <stdarg.h>
 #include <linux/kernel.h>
 #include <linux/string.h>