tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: 1c273e10bc0cc7efb933e0ca10e260cdfc9f0b8c commit: 0d3b051adbb72ed81956447d0d1e54d5943ee6f5 csky: Add VDSO with GENERIC_GETTIMEOFDAY, GENERIC_TIME_VSYSCALL, HAVE_GENERIC_VDSO date: 3 weeks ago config: csky-randconfig-r025-20210321 (attached as .config) compiler: csky-linux-gcc (GCC) 9.3.0 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 # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit... git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git git fetch --no-tags linus master git checkout 0d3b051adbb72ed81956447d0d1e54d5943ee6f5 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=csky If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): 90 | uint64_t csky_pmu_read_cc(void) | ^~~~~~~~~~~~~~~~ arch/csky/kernel/perf_event.c:878:6: warning: no previous prototype for 'csky_pmu_event_set_period' [-Wmissing-prototypes] 878 | int csky_pmu_event_set_period(struct perf_event *event) | ^~~~~~~~~~~~~~~~~~~~~~~~~ arch/csky/kernel/perf_event.c:1198:5: warning: no previous prototype for 'init_hw_perf_events' [-Wmissing-prototypes] 1198 | int init_hw_perf_events(void) | ^~~~~~~~~~~~~~~~~~~ arch/csky/kernel/perf_event.c:1293:5: warning: no previous prototype for 'csky_pmu_device_probe' [-Wmissing-prototypes] 1293 | int csky_pmu_device_probe(struct platform_device *pdev, | ^~~~~~~~~~~~~~~~~~~~~ vim +/csky_pmu_read_cc +90 arch/csky/kernel/perf_event.c 88 89 /* cycle counter */ 91 { 92 uint32_t lo, hi, tmp; 93 uint64_t result; 94 95 do { 96 tmp = cprgr("<0, 0x3>"); 97 lo = cprgr("<0, 0x2>"); 98 hi = cprgr("<0, 0x3>"); 99 } while (hi != tmp); 100 101 result = (uint64_t) (hi) << 32; 102 result |= lo; 103 104 return result; 105 } 106 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org