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-rw-r--r--include/linux/bits.h22
1 files changed, 20 insertions, 2 deletions
diff --git a/include/linux/bits.h b/include/linux/bits.h
index a740bbcf3cd2..4671fbf28842 100644
--- a/include/linux/bits.h
+++ b/include/linux/bits.h
@@ -18,12 +18,30 @@
* position @h. For example
* GENMASK_ULL(39, 21) gives us the 64bit vector 0x000000ffffe00000.
*/
-#define GENMASK(h, l) \
+#if !defined(__ASSEMBLY__) && \
+ (!defined(CONFIG_CC_IS_GCC) || CONFIG_GCC_VERSION >= 49000)
+#include <linux/build_bug.h>
+#define GENMASK_INPUT_CHECK(h, l) \
+ (BUILD_BUG_ON_ZERO(__builtin_choose_expr( \
+ __builtin_constant_p((l) > (h)), (l) > (h), 0)))
+#else
+/*
+ * BUILD_BUG_ON_ZERO is not available in h files included from asm files,
+ * disable the input check if that is the case.
+ */
+#define GENMASK_INPUT_CHECK(h, l) 0
+#endif
+
+#define __GENMASK(h, l) \
(((~UL(0)) - (UL(1) << (l)) + 1) & \
(~UL(0) >> (BITS_PER_LONG - 1 - (h))))
+#define GENMASK(h, l) \
+ (GENMASK_INPUT_CHECK(h, l) + __GENMASK(h, l))
-#define GENMASK_ULL(h, l) \
+#define __GENMASK_ULL(h, l) \
(((~ULL(0)) - (ULL(1) << (l)) + 1) & \
(~ULL(0) >> (BITS_PER_LONG_LONG - 1 - (h))))
+#define GENMASK_ULL(h, l) \
+ (GENMASK_INPUT_CHECK(h, l) + __GENMASK_ULL(h, l))
#endif /* __LINUX_BITS_H */