tree: https://git.kernel.org/pub/scm/linux/kernel/git/lpieralisi/pci.git pci/mips head: 783399b028bd386a2969d3d0a292afc48260ab70 commit: b73ad3d4e22e3466ebc8af1f2e04b307b729eb05 [2/3] PCI: Add Loongson PCI Controller support config: x86_64-allyesconfig (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 x86_64 cross compiling tool for clang build # apt-get install binutils-x86-64-linux-gnu git checkout b73ad3d4e22e3466ebc8af1f2e04b307b729eb05 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64 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 <<): drivers/pci/controller/pci-loongson.c:49:6: warning: unused variable 'tmp' [-Wunused-variable] u16 tmp; ^ void __iomem *pci_loongson_map_bus(struct pci_bus *bus, unsigned int devfn, ^ drivers/pci/controller/pci-loongson.c:120:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void __iomem *pci_loongson_map_bus(struct pci_bus *bus, unsigned int devfn, ^ static 2 warnings generated. vim +/pci_loongson_map_bus +120 drivers/pci/controller/pci-loongson.c 119 121 int where) 122 { 123 unsigned char busnum = bus->number; 124 struct pci_host_bridge *bridge = pci_find_host_bridge(bus); 125 struct loongson_pci *priv = pci_host_bridge_priv(bridge); 126 127 /* 128 * Do not read more than one device on the bus other than 129 * the host bus. For our hardware the root bus is always bus 0. 130 */ 131 if (priv->flags & FLAG_DEV_FIX && busnum != 0 && 132 PCI_SLOT(devfn) > 0) 133 return NULL; 134 135 /* CFG0 can only access standard space */ 136 if (where < PCI_CFG_SPACE_SIZE && priv->cfg0_base) 137 return cfg0_map(priv, busnum, devfn, where); 138 139 /* CFG1 can access extended space */ 140 if (where < PCI_CFG_SPACE_EXP_SIZE && priv->cfg1_base) 141 return cfg1_map(priv, busnum, devfn, where); 142 143 return NULL; 144 } 145 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org