Hi Christoph,

FYI, the error/warning still remains.

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   dea8dcf2a9fa8cc540136a6cd885c3beece16ec3
commit: 7bc5c428a660d4d1bc95ba54bf4cb6bccf8c3029 dma-direct: remove __dma_to_phys
date:   4 months ago
config: mips-randconfig-s031-20201220 (attached as .config)
compiler: mips64-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: v0.6.3-184-g1b896707-dirty
        # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7bc5c428a660d4d1bc95ba54bf4cb6bccf8c3029
        git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
        git fetch --no-tags linus master
        git checkout 7bc5c428a660d4d1bc95ba54bf4cb6bccf8c3029
        # 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=mips 

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 >>):

   mips64-linux-ld: kernel/dma/mapping.o: in function `dma_map_page_attrs':
   mapping.c:(.text+0x108): undefined reference to `__phys_to_dma'
   mips64-linux-ld: kernel/dma/mapping.o: in function `dma_unmap_page_attrs':
>> mapping.c:(.text+0x24c): undefined reference to `dma_to_phys'
>> mips64-linux-ld: mapping.c:(.text+0x28c): undefined reference to `dma_to_phys'
   mips64-linux-ld: kernel/dma/mapping.o: in function `dma_sync_single_for_cpu':
   mapping.c:(.text+0x490): undefined reference to `dma_to_phys'
   mips64-linux-ld: kernel/dma/mapping.o: in function `dma_sync_single_for_device':
   mapping.c:(.text+0x4f0): undefined reference to `dma_to_phys'
   mips64-linux-ld: kernel/dma/direct.o: in function `dma_direct_get_required_mask':
   direct.c:(.text+0xb4): undefined reference to `__phys_to_dma'
   mips64-linux-ld: kernel/dma/direct.o: in function `dma_direct_alloc':
>> direct.c:(.text+0x1dc): undefined reference to `dma_to_phys'
   mips64-linux-ld: direct.c:(.text+0x2bc): undefined reference to `__phys_to_dma'
   mips64-linux-ld: direct.c:(.text+0x398): undefined reference to `__phys_to_dma'
>> mips64-linux-ld: direct.c:(.text+0x428): undefined reference to `dma_to_phys'
   mips64-linux-ld: kernel/dma/direct.o: in function `dma_direct_free':
   direct.c:(.text+0x55c): undefined reference to `dma_to_phys'
   mips64-linux-ld: kernel/dma/direct.o: in function `dma_direct_map_sg':
   direct.c:(.text+0x69c): undefined reference to `__phys_to_dma'
   mips64-linux-ld: kernel/dma/direct.o: in function `dma_direct_get_sgtable':
   direct.c:(.text+0x8c8): undefined reference to `dma_to_phys'
   mips64-linux-ld: kernel/dma/direct.o: in function `dma_direct_mmap':
   direct.c:(.text+0x9cc): undefined reference to `dma_to_phys'
   mips64-linux-ld: kernel/dma/direct.o: in function `dma_direct_supported':
   direct.c:(.text+0xaa8): undefined reference to `__phys_to_dma'
   mips64-linux-ld: kernel/dma/direct.o: in function `dma_direct_need_sync':
   direct.c:(.text+0xad8): undefined reference to `dma_to_phys'

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