On Sat, Mar 08, 2025 at 01:48:49AM +0900, Vincent Mailhol via B4 Relay wrote: > From: Yury Norov <yury.norov@xxxxxxxxx> > > Add GENMASK_TYPE() which generalizes __GENMASK() to support different > types, and implement fixed-types versions of GENMASK() based on it. > The fixed-type version allows more strict checks to the min/max values > accepted, which is useful for defining registers like implemented by > i915 and xe drivers with their REG_GENMASK*() macros. > > The strict checks rely on shift-count-overflow compiler check to fail > the build if a number outside of the range allowed is passed. > Example: > > #define FOO_MASK GENMASK_U32(33, 4) > > will generate a warning like: > > include/linux/bits.h:51:27: error: right shift count >= width of type [-Werror=shift-count-overflow] > 51 | type_max(t) >> (BITS_PER_TYPE(t) - 1 - (h))))) > | ^~ ... > /* > * Missing asm support > * > + * GENMASK_U*() depends on BITS_PER_TYPE() which relies on sizeof(), s/depends/depend/ (we are already referring to a plural) > + * something not available in asm. Nethertheless, fixed width integers > + * is a C concept. Assembly code can rely on the long and long long > + * versions instead. > */ -- With Best Regards, Andy Shevchenko
