tree: https://github.com/tobetter/linux odroid-5.16.y head: 04f296b5f991198f16f76ba15a23e9e00e30aac4 commit: 6720769118c835b66f65eb40c2d476fd615d9549 [20/75] ODROID-XU4: char: exynos: add /dev/gpiomem device for rootless user GPIO access config: um-i386_defconfig (https://download.01.org/0day-ci/archive/20211209/202112090115.CsqYVkoF-lk...) compiler: gcc-9 (Debian 9.3.0-22) 9.3.0 reproduce (this is a W=1 build): # https://github.com/tobetter/linux/commit/6720769118c835b66f65eb40c2d476fd... git remote add tobetter https://github.com/tobetter/linux git fetch --no-tags tobetter odroid-5.16.y git checkout 6720769118c835b66f65eb40c2d476fd615d9549 # save the config file to linux build tree mkdir build_dir make W=1 O=build_dir ARCH=um SUBARCH=i386 SHELL=/bin/bash drivers/char/ 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 >>): drivers/char/exynos-gpiomem.c: In function 'exynos_gpiomem_mmap': drivers/char/exynos-gpiomem.c:121:22: error: implicit declaration of function 'phys_mem_access_prot'; did you mean 'phys_mem_access_prot_allowed'? [-Werror=implicit-function-declaration] 121 | vma->vm_page_prot = phys_mem_access_prot(file, vma->vm_pgoff, | ^~~~~~~~~~~~~~~~~~~~ | phys_mem_access_prot_allowed cc1: some warnings being treated as errors vim +121 drivers/char/exynos-gpiomem.c 106 107 static int exynos_gpiomem_mmap(struct file *file, struct vm_area_struct *vma) 108 { 109 int gpio_area = 0; 110 111 while (gpio_area < inst->gpio_area_count) { 112 if ((inst->gpio_regs_phys[gpio_area] >> PAGE_SHIFT) == vma->vm_pgoff) 113 goto found; 114 115 gpio_area++; 116 } 117 118 return -EACCES; 119 120 found: 122 PAGE_SIZE, 123 vma->vm_page_prot); 124 125 vma->vm_ops = &exynos_gpiomem_vm_ops; 126 127 if (remap_pfn_range(vma, vma->vm_start, 128 vma->vm_pgoff, 129 PAGE_SIZE, 130 vma->vm_page_prot)) { 131 return -EAGAIN; 132 } 133 134 return 0; 135 } 136 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org