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

From: Kees Cook
Date: Thu Jan 11 2018 - 15:33:06 EST


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