GENMASK_ULL performs a left-shift of (~0ULL), which technically results in an integer overflow. clang raises a warning about this if the overflow occurs in a preprocessor expression. To avoid the overflow first perform a right-shift to clear the bits that are shifted out.
Signed-off-by: Matthias Kaehlcke <[email protected]> --- 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 a83c822c35c2..21dfe63001e3 100644 --- a/include/linux/bitops.h +++ b/include/linux/bitops.h @@ -22,7 +22,7 @@ (((~0UL) << (l)) & (~0UL >> (BITS_PER_LONG - 1 - (h)))) #define GENMASK_ULL(h, l) \ - (((~0ULL) << (l)) & (~0ULL >> (BITS_PER_LONG_LONG - 1 - (h)))) + ((((~0ULL) >> (l)) << (l)) & (~0ULL >> (BITS_PER_LONG_LONG - 1 - (h)))) extern unsigned int __sw_hweight8(unsigned int w); extern unsigned int __sw_hweight16(unsigned int w); -- 2.14.0.rc1.383.gd1ce394fe2-goog
