Hi Jérôme,

First bad commit (maybe != root cause):

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   1590a2e1c681b0991bd42c992cabfd380e0338f2
commit: 53707c85d2c1ffe844266368cb7c7db137161881 staging: wfx: correctly cast data on big-endian targets
date:   9 months ago
config: microblaze-randconfig-r026-20200624 (attached as .config)
compiler: microblaze-linux-gcc (GCC) 9.3.0
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
        git checkout 53707c85d2c1ffe844266368cb7c7db137161881
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=microblaze 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   ERROR: "min_low_pfn" [drivers/block/aoe/aoe.ko] undefined!
>> ERROR: "min_low_pfn" [drivers/staging/wfx/wfx.ko] undefined!
   ERROR: "min_low_pfn" [drivers/scsi/qedf/qedf.ko] undefined!

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