Hi Nicholas, I love your patch! Yet something to improve: [auto build test ERROR on arm64/for-next/core] [also build test ERROR on powerpc/next tip/x86/mm linus/master v5.7-rc1 next-20200413] [if your patch is applied to the wrong git tree, please drop us a note to help improve the system. BTW, we also suggest to use '--base' option to specify the base tree in git format-patch, please see https://stackoverflow.com/a/37406982] url: https://github.com/0day-ci/linux/commits/Nicholas-Piggin/huge-vmalloc-map... base: https://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-next/core config: nds32-defconfig (attached as .config) compiler: nds32le-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 # save the attached .config to linux build tree GCC_VERSION=9.3.0 make.cross ARCH=nds32 If you fix the issue, kindly add following tag as appropriate Reported-by: kbuild test robot <lkp(a)intel.com&gt; All errors (new ones prefixed by >>): <stdin>:1511:2: warning: #warning syscall clone3 not implemented [-Wcpp] In file included from include/asm-generic/io.h:887, from arch/nds32/include/asm/io.h:82, from arch/nds32/kernel/vdso/gettimeofday.c:7: 94 | static inline bool arch_vmap_pmd_supported(prprot_t prot) { return false; } | ^~~~~~~~ | pgprot_t make[2]: *** [scripts/Makefile.build:268: arch/nds32/kernel/vdso/gettimeofday.o] Error 1 make[2]: Target 'include/generated/vdso-offsets.h' not remade because of errors. make[1]: *** [arch/nds32/Makefile:63: vdso_prepare] Error 2 make[1]: Target 'prepare' not remade because of errors. make: *** [Makefile:179: sub-make] Error 2 35 real 5 user 12 sys 50.54% cpu make prepare vim +94 include/linux/vmalloc.h 86 87 #ifdef CONFIG_HAVE_ARCH_HUGE_VMAP 88 bool arch_vmap_p4d_supported(pgprot_t prot); 89 bool arch_vmap_pud_supported(pgprot_t prot); 90 bool arch_vmap_pmd_supported(pgprot_t prot); 91 #else 92 static inline bool arch_vmap_p4d_supported(pgprot_t prot) { return false; } 93 static inline bool arch_vmap_pud_supported(pgprot_t prot) { return false; } 95 #endif 96 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org