tree: https://github.com/tobetter/linux odroid-5.9.y head: a17882c45f6b82a3646f55b5b179fdf7f332ab6a commit: aaf1638fa462820bcbc5f711b79494eeda268f56 [26/72] ODROID-COMMON: pwm: gpio: Add a generic gpio based PWM driver config: s390-randconfig-r032-20200911 (attached as .config) compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project 0448d11a06b451a63a8f60408fec613ad24801ba) 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 git checkout aaf1638fa462820bcbc5f711b79494eeda268f56 # 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 include/linux/gpio/driver.h:7: In file included from include/linux/irq.h:20: In file included from include/linux/io.h:13: In file included from arch/s390/include/asm/io.h:72: 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:119:21: note: expanded from macro '__swab32' ___constant_swab32(x) : \ ^ include/uapi/linux/swab.h:20:12: note: expanded from macro '___constant_swab32' (((__u32)(x) & (__u32)0x0000ff00UL) << 8) | \ ^ In file included from drivers/pwm/pwm-gpio.c:23: In file included from include/linux/of_gpio.h:14: In file included from include/linux/gpio/driver.h:7: In file included from include/linux/irq.h:20: In file included from include/linux/io.h:13: In file included from arch/s390/include/asm/io.h:72: 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:119:21: note: expanded from macro '__swab32' ___constant_swab32(x) : \ ^ include/uapi/linux/swab.h:21:12: note: expanded from macro '___constant_swab32' (((__u32)(x) & (__u32)0x00ff0000UL) >> 8) | \ ^ In file included from drivers/pwm/pwm-gpio.c:23: In file included from include/linux/of_gpio.h:14: In file included from include/linux/gpio/driver.h:7: In file included from include/linux/irq.h:20: In file included from include/linux/io.h:13: In file included from arch/s390/include/asm/io.h:72: 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:119:21: note: expanded from macro '__swab32' ___constant_swab32(x) : \ ^ include/uapi/linux/swab.h:22:12: note: expanded from macro '___constant_swab32' (((__u32)(x) & (__u32)0xff000000UL) >> 24))) ^ In file included from drivers/pwm/pwm-gpio.c:23: In file included from include/linux/of_gpio.h:14: In file included from include/linux/gpio/driver.h:7: In file included from include/linux/irq.h:20: In file included from include/linux/io.h:13: In file included from arch/s390/include/asm/io.h:72: 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:120:12: note: expanded from macro '__swab32' __fswab32(x)) ^ In file included from drivers/pwm/pwm-gpio.c:23: In file included from include/linux/of_gpio.h:14: In file included from include/linux/gpio/driver.h:7: In file included from include/linux/irq.h:20: In file included from include/linux/io.h:13: In file included from arch/s390/include/asm/io.h:72: 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); ~~~~~~~~~~ ^ enum hrtimer_restart gpio_pwm_timer(struct hrtimer *timer) ^ drivers/pwm/pwm-gpio.c:60:1: note: declare 'static' if the function is not intended to be used outside of this translation unit enum hrtimer_restart gpio_pwm_timer(struct hrtimer *timer) ^ static 21 warnings generated. # https://github.com/tobetter/linux/commit/aaf1638fa462820bcbc5f711b79494ee... git remote add tobetter-linux https://github.com/tobetter/linux git fetch --no-tags tobetter-linux odroid-5.9.y git checkout aaf1638fa462820bcbc5f711b79494eeda268f56 vim +/gpio_pwm_timer +60 drivers/pwm/pwm-gpio.c 59 61 { 62 struct gpio_pwm_data *gpio_data = container_of(timer, 63 struct gpio_pwm_data, 64 timer); 65 if (!gpio_data->run) { 66 gpio_pwm_off(gpio_data); 67 gpio_data->pin_on = false; 68 return HRTIMER_NORESTART; 69 } 70 71 if (!gpio_data->pin_on) { 72 hrtimer_forward_now(&gpio_data->timer, 73 ns_to_ktime(gpio_data->on_time)); 74 gpio_pwm_on(gpio_data); 75 gpio_data->pin_on = true; 76 } else { 77 hrtimer_forward_now(&gpio_data->timer, 78 ns_to_ktime(gpio_data->off_time)); 79 gpio_pwm_off(gpio_data); 80 gpio_data->pin_on = false; 81 } 82 83 return HRTIMER_RESTART; 84 } 85 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org