Hi Vincenzo,

I love your patch! Yet something to improve:

[auto build test ERROR on kvmarm/next]
[also build test ERROR on linus/master v5.12-rc2 next-20210305]
[cannot apply to arm64/for-next/core xlnx/master arm/for-next soc/for-next hnaz-linux-mm/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/Vincenzo-Frascino/arm64-ARMv8-5-A-MTE-Add-async-mode-support/20210309-001716
base:   https://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm.git next
config: arm64-randconfig-r021-20210308 (attached as .config)
compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project 3a11a41795bec548e91621caaa4cc00fc31b2212)
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 arm64 cross compiling tool for clang build
        # apt-get install binutils-aarch64-linux-gnu
        # https://github.com/0day-ci/linux/commit/660df126323fe5533a1be7834e1754a1adc69f13
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Vincenzo-Frascino/arm64-ARMv8-5-A-MTE-Add-async-mode-support/20210309-001716
        git checkout 660df126323fe5533a1be7834e1754a1adc69f13
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=arm64 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <redacted>

All errors (new ones prefixed by >>):

quoted

ld.lld: error: undefined symbol: mte_async_mode

   >>> referenced by maccess.c
   >>>               maccess.o:(copy_from_kernel_nofault) in archive mm/built-in.a
   >>> referenced by maccess.c
   >>>               maccess.o:(copy_from_kernel_nofault) in archive mm/built-in.a
   >>> referenced by maccess.c
   >>>               maccess.o:(copy_from_kernel_nofault) in archive mm/built-in.a
   >>> referenced 62 more times

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org