tree: https://github.com/frank-w/BPI-R2-4.14 5.12-rc head: a274b03ce7a694aa026d66d7a1f855b0a1021fec commit: 7375bbfd405f43557966d0710d0d019f1e290634 [25/28] PCI: mediatek: Add new method to get shared pcie-cfg base address and parse node config: s390-randconfig-r036-20210324 (attached as .config) compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project a4fb88669cd98db6fef7dcac88e3ec425d40c00d) 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 s390 cross compiling tool for clang build # apt-get install binutils-s390x-linux-gnu # https://github.com/frank-w/BPI-R2-4.14/commit/7375bbfd405f43557966d0710d0... git remote add frank-w-bpi-r2-4.14 https://github.com/frank-w/BPI-R2-4.14 git fetch --no-tags frank-w-bpi-r2-4.14 5.12-rc git checkout 7375bbfd405f43557966d0710d0d019f1e290634 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=s390 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 >>): In file included from drivers/pci/controller/pcie-mediatek.c:12: In file included from include/linux/iopoll.h:14: In file included from include/linux/io.h:13: In file included from arch/s390/include/asm/io.h:80: include/asm-generic/io.h:464:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] val = __raw_readb(PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:477:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr)); ~~~~~~~~~~ ^ include/uapi/linux/byteorder/big_endian.h:36:59: note: expanded from macro '__le16_to_cpu' #define __le16_to_cpu(x) __swab16((__force __u16)(__le16)(x)) ^ include/uapi/linux/swab.h:102:54: note: expanded from macro '__swab16' #define __swab16(x) (__u16)__builtin_bswap16((__u16)(x)) ^ In file included from drivers/pci/controller/pcie-mediatek.c:12: In file included from include/linux/iopoll.h:14: In file included from include/linux/io.h:13: In file included from arch/s390/include/asm/io.h:80: include/asm-generic/io.h:490:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr)); ~~~~~~~~~~ ^ include/uapi/linux/byteorder/big_endian.h:34:59: note: expanded from macro '__le32_to_cpu' #define __le32_to_cpu(x) __swab32((__force __u32)(__le32)(x)) ^ include/uapi/linux/swab.h:115:54: note: expanded from macro '__swab32' #define __swab32(x) (__u32)__builtin_bswap32((__u32)(x)) ^ In file included from drivers/pci/controller/pcie-mediatek.c:12: In file included from include/linux/iopoll.h:14: In file included from include/linux/io.h:13: In file included from arch/s390/include/asm/io.h:80: include/asm-generic/io.h:501:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] __raw_writeb(value, PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:511:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:521:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:609:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] readsb(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:617:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] readsw(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:625:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] readsl(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:634:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] writesb(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:643:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] writesw(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:652:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] writesl(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ if (err) ^~~~~~~~ include/linux/compiler.h:56:28: note: expanded from macro 'if' #define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) ) ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ include/linux/compiler.h:58:30: note: expanded from macro '__trace_if_var' #define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond)) ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ drivers/pci/controller/pcie-mediatek.c:1090:14: note: uninitialized use occurs here of_node_put(child); ^~~~~ drivers/pci/controller/pcie-mediatek.c:1072:3: note: remove the 'if' if its condition is always false if (err) ^~~~~~~~ include/linux/compiler.h:56:23: note: expanded from macro 'if' #define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) ) ^ drivers/pci/controller/pcie-mediatek.c:1051:49: note: initialize the variable 'child' to silence this warning struct device_node *node = dev->of_node, *child; ^ = NULL 13 warnings generated. vim +1072 drivers/pci/controller/pcie-mediatek.c 1047 1048 static int mtk_pcie_setup(struct mtk_pcie *pcie) 1049 { 1050 struct device *dev = pcie->dev; 1051 struct device_node *node = dev->of_node, *child; 1052 struct mtk_pcie_port *port, *tmp; 1053 int err, slot; 1054 1055 slot = of_get_pci_domain_nr(dev->of_node); 1056 if (slot < 0) { 1057 for_each_available_child_of_node(node, child) { 1058 err = of_pci_get_devfn(child); 1059 if (err < 0) { 1060 dev_err(dev, "failed to get devfn: %d\n", err); 1061 goto error_put_node; 1062 } 1063 1064 slot = PCI_SLOT(err); 1065 1066 err = mtk_pcie_parse_port(pcie, child, slot); 1067 if (err) 1068 goto error_put_node; 1069 } 1070 } else { 1071 err = mtk_pcie_parse_port(pcie, node, slot); 1073 goto error_put_node; 1074 } 1075 1076 err = mtk_pcie_subsys_powerup(pcie); 1077 if (err) 1078 return err; 1079 1080 /* enable each port, and then check link status */ 1081 list_for_each_entry_safe(port, tmp, &pcie->ports, list) 1082 mtk_pcie_enable_port(port); 1083 1084 /* power down PCIe subsys if slots are all empty (link down) */ 1085 if (list_empty(&pcie->ports)) 1086 mtk_pcie_subsys_powerdown(pcie); 1087 1088 return 0; 1089 error_put_node: 1090 of_node_put(child); 1091 return err; 1092 } 1093 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org