Hi Jianyong, [FYI, it's a private test report for your RFC patch.] [auto build test WARNING on linus/master] [also build test WARNING on v5.7-rc7] [cannot apply to tip/timers/core kvmarm/next kvm/linux-next next-20200526] [if your patch is applied to the wrong git tree, please drop us a note to help improve the system. BTW, we also suggest to use '--base' option to specify the base tree in git format-patch, please see https://stackoverflow.com/a/37406982] url: https://github.com/0day-ci/linux/commits/Jianyong-Wu/Enable-ptp_kvm-for-a... base: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 051143e1602d90ea71887d92363edd539d411de5 config: arm64-randconfig-r001-20200526 (attached as .config) compiler: clang version 11.0.0 (https://github.com/llvm/llvm-project 3393cc4cebf9969db94dc424b7a2b6195589c33b) 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: kbuild test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>, old ones prefixed by <<): int kvm_arch_ptp_init(void) ^ drivers/ptp/ptp_kvm_arm64.c:18:1: note: declare 'static' if the function is not intended to be used outside of this translation unit int kvm_arch_ptp_init(void) ^ static int kvm_arch_ptp_get_clock_generic(struct timespec64 *ts, ^ drivers/ptp/ptp_kvm_arm64.c:30:1: note: declare 'static' if the function is not intended to be used outside of this translation unit int kvm_arch_ptp_get_clock_generic(struct timespec64 *ts, ^ static int kvm_arch_ptp_get_clock(struct timespec64 *ts) ^ drivers/ptp/ptp_kvm_arm64.c:46:1: note: declare 'static' if the function is not intended to be used outside of this translation unit int kvm_arch_ptp_get_clock(struct timespec64 *ts) ^ static 3 warnings generated. -- int kvm_arch_ptp_get_crosststamp(unsigned long *cycle, struct timespec64 *ts, ^ drivers/clocksource/arm_arch_timer.c:1647:1: note: declare 'static' if the function is not intended to be used outside of this translation unit int kvm_arch_ptp_get_crosststamp(unsigned long *cycle, struct timespec64 *ts, ^ static 1 warning generated. vim +/kvm_arch_ptp_init +18 drivers/ptp/ptp_kvm_arm64.c 17 19 { 20 struct arm_smccc_res hvc_res; 21 22 arm_smccc_1_1_invoke(ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID, 23 &hvc_res); 24 if (!(hvc_res.a0 | BIT(ARM_SMCCC_KVM_FUNC_KVM_PTP))) 25 return -EOPNOTSUPP; 26 27 return 0; 28 } 29 31 struct arm_smccc_res *hvc_res) 32 { 33 ktime_t ktime_overall; 34 35 arm_smccc_1_1_invoke(ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID, 36 hvc_res); 37 if ((int)(hvc_res->a0) < 0) 38 return -EOPNOTSUPP; 39 40 ktime_overall = (long long)hvc_res->a0 << 32 | hvc_res->a1; 41 *ts = ktime_to_timespec64(ktime_overall); 42 43 return 0; 44 } 45 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org