On Thu, Sep 17, 2020 at 12:20 AM Gilad Ben-Yossef <gilad@xxxxxxxxxxxxx> wrote: > > hmm... > > On Wed, Sep 16, 2020 at 4:48 PM kernel test robot <lkp@xxxxxxxxx> wrote: > > > > url: https://github.com/0day-ci/linux/commits/Gilad-Ben-Yossef/add-optional-cache-params-from-DT/20200916-152151 > > base: https://git.kernel.org/pub/scm/linux/kernel/git/herbert/cryptodev-2.6.git master > > config: arm64-randconfig-r015-20200916 (attached as .config) > > compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project 9e3842d60351f986d77dfe0a94f76e4fd895f188) > > reproduce (this is a W=1 build): > > wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross > > chmod +x ~/bin/make.cross > > # install arm64 cross compiling tool for clang build > > # apt-get install binutils-aarch64-linux-gnu > > # save the attached .config to linux build tree > > COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=arm64 > > > > If you fix the issue, kindly add following tag as appropriate > > Reported-by: kernel test robot <lkp@xxxxxxxxx> > > > > All warnings (new ones prefixed by >>): > > > > >> drivers/crypto/ccree/cc_driver.c:120:18: warning: result of comparison of constant 18446744073709551615 with expression of type 'u32' (aka 'unsigned int') is always false [-Wtautological-constant-out-of-range-compare] > > cache_params |= FIELD_PREP(mask, val); > > ^~~~~~~~~~~~~~~~~~~~~ > > include/linux/bitfield.h:94:3: note: expanded from macro 'FIELD_PREP' > > __BF_FIELD_CHECK(_mask, 0ULL, _val, "FIELD_PREP: "); \ > > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > include/linux/bitfield.h:52:28: note: expanded from macro '__BF_FIELD_CHECK' > > BUILD_BUG_ON_MSG((_mask) > (typeof(_reg))~0ull, \ > > ~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > include/linux/build_bug.h:39:58: note: expanded from macro 'BUILD_BUG_ON_MSG' > > #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg) > > ~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~ > > include/linux/compiler_types.h:319:22: note: expanded from macro 'compiletime_assert' > > _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__) > > ~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > include/linux/compiler_types.h:307:23: note: expanded from macro '_compiletime_assert' > > __compiletime_assert(condition, msg, prefix, suffix) > > ~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > include/linux/compiler_types.h:299:9: note: expanded from macro '__compiletime_assert' > > if (!(condition)) \ > > ^~~~~~~~~ > > I am unable to understand this warning. It looks like it is > complaining about a FIELD_GET sanity check that is always false, which > makes sense since we're using a constant. > > Anyone can enlighten me if I've missed something? Looked at some of this code recently. I think it may have an issue for masks where sizeof(mask) < sizeof(unsigned long long). In your code, via 0day bot: 107 u32 cache_params, ace_const, val, mask; ... > 120 cache_params |= FIELD_PREP(mask, val); then in include/linux/bitfield.h, we have: 92 #define FIELD_PREP(_mask, _val) \ 93 ({ \ 94 __BF_FIELD_CHECK(_mask, 0ULL, _val, "FIELD_PREP: "); \ 44 #define __BF_FIELD_CHECK(_mask, _reg, _val, _pfx) \ ... 52 BUILD_BUG_ON_MSG((_mask) > (typeof(_reg))~0ull, \ 53 _pfx "type of reg too small for mask"); \ so the 0ULL in FIELD_PREP is important. In __BF_FIELD_CHECK, the typeof(_reg) is unsigned long long (because 0ULL was passed). So we have a comparison between a u32 and a u64; indeed any u32 can never be greater than a u64 that we know has the value of ULLONG_MAX. I did send a series splitting these up, I wonder if they'd help here: https://lore.kernel.org/lkml/20200708230402.1644819-3-ndesaulniers@xxxxxxxxxx/ -- Thanks, ~Nick Desaulniers
