include/asm-generic/io.h:464:31: error: performing pointer arithmetic on a null pointer has undefined behavior

[kernel test robot <lkp@intel.com>]

Hi Haijun,

FYI, the error/warning still remains.

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   50cd95ac46548429e5bba7ca75cc97d11a697947
commit: 13e920d93e37fcaef4a9309515798a3cae9dcf19 net: wwan: t7xx: Add core components
date:   3 months ago
config: s390-randconfig-r033-20220820 (https://download.01.org/0day-ci/archive/20220820/202208201655.jW7k2esR-lkp@intel.com/config)
compiler: clang version 16.0.0 (https://github.com/llvm/llvm-project c9a41fe60ab62f7a40049c100adcc8087a47669b)
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://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=13e920d93e37fcaef4a9309515798a3cae9dcf19
        git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
        git fetch --no-tags linus master
        git checkout 13e920d93e37fcaef4a9309515798a3cae9dcf19
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=s390 SHELL=/bin/bash drivers/net/wwan/t7xx/

If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   In file included from drivers/net/wwan/t7xx/t7xx_pci.c:22:
   In file included from include/linux/dma-mapping.h:10:
   In file included from include/linux/scatterlist.h:9:
   In file included from arch/s390/include/asm/io.h:75:
>> include/asm-generic/io.h:464:31: error: performing pointer arithmetic on a null pointer has undefined behavior [-Werror,-Wnull-pointer-arithmetic]
           val = __raw_readb(PCI_IOBASE + addr);
                             ~~~~~~~~~~ ^
   include/asm-generic/io.h:477:61: error: performing pointer arithmetic on a null pointer has undefined behavior [-Werror,-Wnull-pointer-arithmetic]
           val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr));
                                                           ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/big_endian.h:37:59: 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/net/wwan/t7xx/t7xx_pci.c:22:
   In file included from include/linux/dma-mapping.h:10:
   In file included from include/linux/scatterlist.h:9:
   In file included from arch/s390/include/asm/io.h:75:
   include/asm-generic/io.h:490:61: error: performing pointer arithmetic on a null pointer has undefined behavior [-Werror,-Wnull-pointer-arithmetic]
           val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
                                                           ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/big_endian.h:35:59: 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/net/wwan/t7xx/t7xx_pci.c:22:
   In file included from include/linux/dma-mapping.h:10:
   In file included from include/linux/scatterlist.h:9:
   In file included from arch/s390/include/asm/io.h:75:
   include/asm-generic/io.h:501:33: error: performing pointer arithmetic on a null pointer has undefined behavior [-Werror,-Wnull-pointer-arithmetic]
           __raw_writeb(value, PCI_IOBASE + addr);
                               ~~~~~~~~~~ ^
   include/asm-generic/io.h:511:59: error: performing pointer arithmetic on a null pointer has undefined behavior [-Werror,-Wnull-pointer-arithmetic]
           __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
                                                         ~~~~~~~~~~ ^
   include/asm-generic/io.h:521:59: error: performing pointer arithmetic on a null pointer has undefined behavior [-Werror,-Wnull-pointer-arithmetic]
           __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
                                                         ~~~~~~~~~~ ^
   include/asm-generic/io.h:609:20: error: performing pointer arithmetic on a null pointer has undefined behavior [-Werror,-Wnull-pointer-arithmetic]
           readsb(PCI_IOBASE + addr, buffer, count);
                  ~~~~~~~~~~ ^
   include/asm-generic/io.h:617:20: error: performing pointer arithmetic on a null pointer has undefined behavior [-Werror,-Wnull-pointer-arithmetic]
           readsw(PCI_IOBASE + addr, buffer, count);
                  ~~~~~~~~~~ ^
   include/asm-generic/io.h:625:20: error: performing pointer arithmetic on a null pointer has undefined behavior [-Werror,-Wnull-pointer-arithmetic]
           readsl(PCI_IOBASE + addr, buffer, count);
                  ~~~~~~~~~~ ^
   include/asm-generic/io.h:634:21: error: performing pointer arithmetic on a null pointer has undefined behavior [-Werror,-Wnull-pointer-arithmetic]
           writesb(PCI_IOBASE + addr, buffer, count);
                   ~~~~~~~~~~ ^
   include/asm-generic/io.h:643:21: error: performing pointer arithmetic on a null pointer has undefined behavior [-Werror,-Wnull-pointer-arithmetic]
           writesw(PCI_IOBASE + addr, buffer, count);
                   ~~~~~~~~~~ ^
   include/asm-generic/io.h:652:21: error: performing pointer arithmetic on a null pointer has undefined behavior [-Werror,-Wnull-pointer-arithmetic]
           writesl(PCI_IOBASE + addr, buffer, count);
                   ~~~~~~~~~~ ^
   12 errors generated.


vim +464 include/asm-generic/io.h

3f7e212df82ca0 Arnd Bergmann  2009-05-13  450  
9216efafc52ff9 Thierry Reding 2014-10-01  451  /*
9216efafc52ff9 Thierry Reding 2014-10-01  452   * {in,out}{b,w,l}() access little endian I/O. {in,out}{b,w,l}_p() can be
9216efafc52ff9 Thierry Reding 2014-10-01  453   * implemented on hardware that needs an additional delay for I/O accesses to
9216efafc52ff9 Thierry Reding 2014-10-01  454   * take effect.
9216efafc52ff9 Thierry Reding 2014-10-01  455   */
9216efafc52ff9 Thierry Reding 2014-10-01  456  
f009c89df79abe John Garry     2020-03-28  457  #if !defined(inb) && !defined(_inb)
f009c89df79abe John Garry     2020-03-28  458  #define _inb _inb
214ba3584b2e2c Stafford Horne 2020-07-26  459  static inline u8 _inb(unsigned long addr)
9216efafc52ff9 Thierry Reding 2014-10-01  460  {
87fe2d543f8173 Sinan Kaya     2018-04-05  461  	u8 val;
87fe2d543f8173 Sinan Kaya     2018-04-05  462  
87fe2d543f8173 Sinan Kaya     2018-04-05  463  	__io_pbr();
87fe2d543f8173 Sinan Kaya     2018-04-05 @464  	val = __raw_readb(PCI_IOBASE + addr);
abbbbc83a210e9 Will Deacon    2019-02-22  465  	__io_par(val);
87fe2d543f8173 Sinan Kaya     2018-04-05  466  	return val;
9216efafc52ff9 Thierry Reding 2014-10-01  467  }
9216efafc52ff9 Thierry Reding 2014-10-01  468  #endif
9216efafc52ff9 Thierry Reding 2014-10-01  469  

:::::: The code at line 464 was first introduced by commit
:::::: 87fe2d543f817300e13f0ea683f38c122737856e io: change inX() to have their own IO barrier overrides

:::::: TO: Sinan Kaya <okaya@codeaurora.org>
:::::: CC: Arnd Bergmann <arnd@arndb.de>

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