tree:   https://github.com/AsahiLinux/linux nvme/dev
head:   70ce58861f9029c98ddcfb26787a58bbac183cc2
commit: 70ce58861f9029c98ddcfb26787a58bbac183cc2 [17/17] WIP: apple NVMe
config: powerpc64-randconfig-c024-20210805 (attached as .config)
compiler: powerpc-linux-gcc (GCC) 10.3.0
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
        # https://github.com/AsahiLinux/linux/commit/70ce58861f9029c98ddcfb26787a58bbac183cc2
        git remote add asahilinux https://github.com/AsahiLinux/linux
        git fetch --no-tags asahilinux nvme/dev
        git checkout 70ce58861f9029c98ddcfb26787a58bbac183cc2
        # save the attached .config to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-10.3.0 make.cross O=build_dir ARCH=powerpc SHELL=/bin/bash

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 >>):

   powerpc-linux-ld: drivers/nvme/host/pci.o: in function `.nvme_platform_probe':
>> pci.c:(.text+0x725c): undefined reference to `.mbox_request_channel'

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