[PATCH] cris: Mark end of BUG() implementation as unreachable

[Kees Cook]

When building the cris v10 architecture, the compiler doesn't realize that
BUG() doesn't return, so it will complain about functions using BUG()
that are marked with the noreturn attribute:

   mm/usercopy.c: In function 'usercopy_abort':
>> mm/usercopy.c:86:1: warning: 'noreturn' function does return
    }
    ^

This fixes it for v10, similar to how it already works on v32.

Reported-by: kbuild test robot <fengguang.wu@xxxxxxxxx>
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
 arch/cris/include/arch-v10/arch/bug.h | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/arch/cris/include/arch-v10/arch/bug.h b/arch/cris/include/arch-v10/arch/bug.h
index 905afeacfedf..ca9de0b250de 100644
--- a/arch/cris/include/arch-v10/arch/bug.h
+++ b/arch/cris/include/arch-v10/arch/bug.h
@@ -44,18 +44,26 @@ struct bug_frame {
  * not be used like this with newer versions of gcc.
  */
 #define BUG()								\
+do {									\
 	__asm__ __volatile__ ("clear.d [" __stringify(BUG_MAGIC) "]\n\t"\
 			      "movu.w " __stringify(__LINE__) ",$r0\n\t"\
 			      "jump 0f\n\t"				\
 			      ".section .rodata\n"			\
 			      "0:\t.string \"" __FILE__ "\"\n\t"	\
-			      ".previous")
+			      ".previous");				\
+	unreachable();							\
+} while (0)
 #endif
 
 #else
 
 /* This just causes an oops. */
-#define BUG() (*(int *)0 = 0)
+#define BUG()								\
+do {									\
+	(*(int *)0 = 0);						\
+	do {} while (1);						\
+	unreachable();							\
+} while (0)
 
 #endif
 
-- 
2.7.4


-- 
Kees Cook
Pixel Security