Hi Niklas, I love your patch! Yet something to improve: [auto build test ERROR on soc/for-next] [also build test ERROR on sparc/master asm-generic/master v5.12-rc7 next-20210415] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch] url: https://github.com/0day-ci/linux/commits/Niklas-Schnelle/asm-generic-io-h... base: https://git.kernel.org/pub/scm/linux/kernel/git/soc/soc.git for-next config: arc-randconfig-s031-20210415 (attached as .config) compiler: arc-elf-gcc (GCC) 9.3.0 reproduce: wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # apt-get install sparse # sparse version: v0.6.3-280-g2cd6d34e-dirty # https://github.com/0day-ci/linux/commit/f0394115b166f960f12fc7bc48362d0d1... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Niklas-Schnelle/asm-generic-io-h-Silence-Wnull-pointer-arithmetic-warning-on-PCI_IOBASE/20210415-203919 git checkout f0394115b166f960f12fc7bc48362d0d19f67883 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' W=1 ARCH=arc If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All errors (new ones prefixed by >>): In file included from arch/arc/include/asm/io.h:233, from drivers/w1/w1_io.c:6: include/asm-generic/io.h: In function '_inb': 465 | WARN_ONCE(1, "No I/O port support\n"); | ^~~~~~~~~ cc1: some warnings being treated as errors vim +/WARN_ONCE +465 include/asm-generic/io.h 446 447 /* 448 * {in,out}{b,w,l}() access little endian I/O. {in,out}{b,w,l}_p() can be 449 * implemented on hardware that needs an additional delay for I/O accesses to 450 * take effect. 451 */ 452 453 #if !defined(inb) && !defined(_inb) 454 #define _inb _inb 455 static inline u8 _inb(unsigned long addr) 456 { 457 #ifdef PCI_IOBASE 458 u8 val; 459 460 __io_pbr(); 461 val = __raw_readb(PCI_IOBASE + addr); 462 __io_par(val); 463 return val; 464 #else 466 return ~0; 467 #endif 468 } 469 #endif 470 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org