[PATCH] ppc64: Fix issue with gcc 4.0 compiled kernels

I recently had a BUG_ON() go off spuriously on a gcc 4.0 compiled kernel.
It turns out gcc-4.0 was removing a sign extension while earlier gcc
versions would not.  Thinking this to be a compiler bug, I submitted a
report:

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23422

It turns out we need to cast the input in order to tell gcc to sign extend
it.

Thanks to Andrew Pinski for his help on this bug.

Signed-off-by: Anton Blanchard <anton@samba.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/include/asm-ppc64/bug.h b/include/asm-ppc64/bug.h
index 169868f..1601782 100644 (file)
--- a/include/asm-ppc64/bug.h
+++ b/include/asm-ppc64/bug.h
@@ -43,8 +43,8 @@ struct bug_entry *find_bug(unsigned long bugaddr);
                ".section __bug_table,\"a\"\n\t"                \
                "       .llong 1b,%1,%2,%3\n"                   \
                ".previous"                                     \
-               : : "r" (x), "i" (__LINE__), "i" (__FILE__),    \
-                   "i" (__FUNCTION__));                        \
+               : : "r" ((long long)(x)), "i" (__LINE__),       \
+                   "i" (__FILE__), "i" (__FUNCTION__));        \
 } while (0)
 
 #define WARN_ON(x) do {                                                \
@@ -53,7 +53,8 @@ struct bug_entry *find_bug(unsigned long bugaddr);
                ".section __bug_table,\"a\"\n\t"                \
                "       .llong 1b,%1,%2,%3\n"                   \
                ".previous"                                     \
-               : : "r" (x), "i" (__LINE__ + BUG_WARNING_TRAP), \
+               : : "r" ((long long)(x)),                       \
+                   "i" (__LINE__ + BUG_WARNING_TRAP),          \
                    "i" (__FILE__), "i" (__FUNCTION__));        \
 } while (0)