Hi Ard, I love your patch! Perhaps something to improve: [auto build test WARNING on arm64/for-next/core] [also build test WARNING on arm/for-next soc/for-next kvmarm/next v5.9 next-20201009] [cannot apply to xlnx/master] [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/Ard-Biesheuvel/arm64-mm-set-ZONE... base: https://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-next/core config: arm64-randconfig-s031-20201012 (attached as .config) compiler: aarch64-linux-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-rc1-dirty # https://github.com/0day-ci/linux/commit/887b39ea481d299f24bd5ed803deec25e... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Ard-Biesheuvel/arm64-mm-set-ZONE_DMA-size-based-on-early-IORT-scan/20201011-071053 git checkout 887b39ea481d299f24bd5ed803deec25e61ac6ec # 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__' ARCH=arm64 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 >>): drivers/acpi/arm64/iort.c:1725:21: warning: no previous prototype for 'acpi_iort_get_zone_dma_size' [-Wmissing-prototypes] 1725 | unsigned int __init acpi_iort_get_zone_dma_size(void) | ^~~~~~~~~~~~~~~~~~~~~~~~~~~ drivers/acpi/arm64/iort.c: In function 'acpi_iort_get_zone_dma_size': drivers/acpi/arm64/iort.c:1760:33: warning: suggest braces around empty body in an 'if' statement [-Wempty-body] 1760 | if (rc->memory_address_limit); | ^ In file included from include/linux/ioport.h:13, from include/linux/acpi.h:12, from include/linux/acpi_iort.h:10, from drivers/acpi/arm64/iort.c:13: 56 | #define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) ) | ^~ drivers/acpi/arm64/iort.c:1760:4: note: in expansion of macro 'if' 1760 | if (rc->memory_address_limit); | ^~ drivers/acpi/arm64/iort.c:1761:5: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if' 1761 | limit = min(limit, rc->memory_address_limit); | ^~~~~ vim +/if +56 include/linux/compiler.h 2bcd521a684cc9 Steven Rostedt 2008-11-21 50 2bcd521a684cc9 Steven Rostedt 2008-11-21 51 #ifdef CONFIG_PROFILE_ALL_BRANCHES 2bcd521a684cc9 Steven Rostedt 2008-11-21 52 /* 2bcd521a684cc9 Steven Rostedt 2008-11-21 53 * "Define 'is'", Bill Clinton 2bcd521a684cc9 Steven Rostedt 2008-11-21 54 * "Define 'if'", Steven Rostedt 2bcd521a684cc9 Steven Rostedt 2008-11-21 55 */ a15fd609ad53a6 Linus Torvalds 2019-03-20 @56 #define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) ) a15fd609ad53a6 Linus Torvalds 2019-03-20 57 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org