| From ff7caad9634f2c983d2693d592216c75bed95624 Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Thu, 4 Jun 2020 16:50:30 -0700 |
| Subject: include/linux/bitops.h: avoid clang shift-count-overflow warnings |
| |
| From: Arnd Bergmann <arnd@arndb.de> |
| |
| [ Upstream commit bd93f003b7462ae39a43c531abca37fe7073b866 ] |
| |
| Clang normally does not warn about certain issues in inline functions when |
| it only happens in an eliminated code path. However if something else |
| goes wrong, it does tend to complain about the definition of hweight_long() |
| on 32-bit targets: |
| |
| include/linux/bitops.h:75:41: error: shift count >= width of type [-Werror,-Wshift-count-overflow] |
| return sizeof(w) == 4 ? hweight32(w) : hweight64(w); |
| ^~~~~~~~~~~~ |
| include/asm-generic/bitops/const_hweight.h:29:49: note: expanded from macro 'hweight64' |
| define hweight64(w) (__builtin_constant_p(w) ? __const_hweight64(w) : __arch_hweight64(w)) |
| ^~~~~~~~~~~~~~~~~~~~ |
| include/asm-generic/bitops/const_hweight.h:21:76: note: expanded from macro '__const_hweight64' |
| define __const_hweight64(w) (__const_hweight32(w) + __const_hweight32((w) >> 32)) |
| ^ ~~ |
| include/asm-generic/bitops/const_hweight.h:20:49: note: expanded from macro '__const_hweight32' |
| define __const_hweight32(w) (__const_hweight16(w) + __const_hweight16((w) >> 16)) |
| ^ |
| include/asm-generic/bitops/const_hweight.h:19:72: note: expanded from macro '__const_hweight16' |
| define __const_hweight16(w) (__const_hweight8(w) + __const_hweight8((w) >> 8 )) |
| ^ |
| include/asm-generic/bitops/const_hweight.h:12:9: note: expanded from macro '__const_hweight8' |
| (!!((w) & (1ULL << 2))) + \ |
| |
| Adding an explicit cast to __u64 avoids that warning and makes it easier |
| to read other output. |
| |
| Signed-off-by: Arnd Bergmann <arnd@arndb.de> |
| Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
| Acked-by: Christian Brauner <christian.brauner@ubuntu.com> |
| Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> |
| Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> |
| Cc: Josh Poimboeuf <jpoimboe@redhat.com> |
| Cc: Nick Desaulniers <ndesaulniers@google.com> |
| Link: http://lkml.kernel.org/r/20200505135513.65265-1-arnd@arndb.de |
| Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| include/linux/bitops.h | 2 +- |
| 1 file changed, 1 insertion(+), 1 deletion(-) |
| |
| diff --git a/include/linux/bitops.h b/include/linux/bitops.h |
| index c51574fab0b00..00dcb1bad76b8 100644 |
| --- a/include/linux/bitops.h |
| +++ b/include/linux/bitops.h |
| @@ -50,7 +50,7 @@ static inline int get_bitmask_order(unsigned int count) |
| |
| static __always_inline unsigned long hweight_long(unsigned long w) |
| { |
| - return sizeof(w) == 4 ? hweight32(w) : hweight64(w); |
| + return sizeof(w) == 4 ? hweight32(w) : hweight64((__u64)w); |
| } |
| |
| /** |
| -- |
| 2.25.1 |
| |