Hi Besar, kernel test robot noticed the following build warnings: [auto build test WARNING on ea8d1c062a0e876e999e4f347daeb598d5e677ab] url: https://github.com/intel-lab-lkp/linux/commits/Besar-Wicaksono/perf-arm_cspmu-Separate-Arm-and-vendor-module/20230620-121723 base: ea8d1c062a0e876e999e4f347daeb598d5e677ab patch link: https://lore.kernel.org/r/20230620041438.32514-1-bwicaksono%40nvidia.com patch subject: [PATCH v4] perf: arm_cspmu: Separate Arm and vendor module config: arm64-defconfig (https://download.01.org/0day-ci/archive/20230620/202306201854.S2tjTpWE-lkp@xxxxxxxxx/config) compiler: aarch64-linux-gcc (GCC) 12.3.0 reproduce: (https://download.01.org/0day-ci/archive/20230620/202306201854.S2tjTpWE-lkp@xxxxxxxxx/reproduce) If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags | Reported-by: kernel test robot <lkp@xxxxxxxxx> | Closes: https://lore.kernel.org/oe-kbuild-all/202306201854.S2tjTpWE-lkp@xxxxxxxxx/ All warnings (new ones prefixed by >>): >> drivers/perf/arm_cspmu/arm_cspmu.c:386:30: warning: no previous prototype for 'arm_cspmu_impl_match_get' [-Wmissing-prototypes] 386 | struct arm_cspmu_impl_match *arm_cspmu_impl_match_get(u32 pmiidr) | ^~~~~~~~~~~~~~~~~~~~~~~~ vim +/arm_cspmu_impl_match_get +386 drivers/perf/arm_cspmu/arm_cspmu.c 385 > 386 struct arm_cspmu_impl_match *arm_cspmu_impl_match_get(u32 pmiidr) 387 { 388 struct arm_cspmu_impl_match *match = impl_match; 389 390 for (; match->pmiidr_val; match++) { 391 u32 mask = match->pmiidr_mask; 392 393 if ((match->pmiidr_val & mask) == (pmiidr & mask)) 394 break; 395 } 396 397 return match; 398 } 399 -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki