On Wednesday 06 Jan 2021 at 15:21:19 (+0000), Catalin Marinas wrote: > On Wed, Jan 06, 2021 at 03:07:24PM +0000, Ionela Voinescu wrote: > > On Friday 18 Dec 2020 at 10:44:10 (+0000), Catalin Marinas wrote: > > > On Fri, Dec 18, 2020 at 05:00:16AM +0800, kernel test robot wrote: > > > > tree: > > > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git > > > > master > > > > head: 74f602dc96dd854c7b2034947798c1e2a6b84066 > > > > commit: 68c5debcc06d6d24f15dbf978780fc5efc147d5e arm64: implement CPPC > > > > FFH support using AMUs > > > > date: 5 weeks ago > > > > config: arm64-randconfig-s032-20201217 (attached as .config) > > > > compiler: aarch64-linux-gcc (GCC) 9.3.0 > > > > reproduce: > > > > wget > > > > https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross > > > > -O ~/bin/make.cross > > > > chmod +x ~/bin/make.cross > > > > # apt-get install sparse > > > > # sparse version: v0.6.3-184-g1b896707-dirty > > > > # > > > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=68c5debcc06d6d24f15dbf978780fc5efc147d5e > > > > git remote add linus > > > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git > > > > git fetch --no-tags linus master > > > > git checkout 68c5debcc06d6d24f15dbf978780fc5efc147d5e > > > > # save the attached .config to linux build tree > > > > COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross > > > > C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' ARCH=arm64 > > > > > > > > If you fix the issue, kindly add following tag as appropriate > > > > Reported-by: kernel test robot <l...@intel.com> > > > > > > > > > > > > "sparse warnings: (new ones prefixed by >>)" > > > > >> arch/arm64/kernel/topology.c:367:22: sparse: sparse: dereference of > > > > >> noderef expression > > > > > > > > vim +367 arch/arm64/kernel/topology.c > > > > > > > > 362 > > > > 363 int cpc_read_ffh(int cpu, struct cpc_reg *reg, u64 *val) > > > > 364 { > > > > 365 int ret = -EOPNOTSUPP; > > > > 366 > > > > > 367 switch ((u64)reg->address) { > > > > > > That's not a dereference but I guess sparse complains of dropping the > > > __iomem. We could change the cast to (__force u64) to silence sparse. > > > > > > Thanks for the report. > > > > > > > Nothing I've tried seemed to silence sparse here, including casting to > > (__force u64). > > Would it work if we changed the case lines to (u64 __iomem)0x0? >
No, it does not. We still get the same warning on the switch line even if there is no cast. Same if we directly check for: if (reg->address == (u64 __iomem)0x0) Ionela. > -- > Catalin
