On Wed, Jul 31, 2019 at 12:27:38PM -0700, Joe Perches wrote: > On Wed, 2019-07-31 at 21:03 +0200, Rikard Falkeborn wrote: > > GENMASK() and GENMASK_ULL() are supposed to be called with the high bit > > as the first argument and the low bit as the second argument. Mixing > > them will return a mask with zero bits set. > > A few things: > > o Reading the final code is a bit confusing. > Perhaps add a comment description saying it's not checked > in asm .h uses.
Comment added. > o Maybe use: > #define GENMASK_INPUT_CHECK(h, l) UL(0) Sure. > o The compiler error message when the arguments are in the > wrong order isn't obvious. Is there some way to improve > the compiler error output, maybe by using BUILD_BUG_ON_MSG > or some other mechanism? Not that I could find. BUILD_BUG_ON_MSG can not be used if the macros should be usable in e.g. a structure initializer (this seems to be the whole reason BUILD_BUG_ON_ZERO exists).
