tree:   https://github.com/c-sky/csky-linux linux-5.15-rc1-d1-v4
head:   88c6ea42e010e46e58be159efa07cda22d95a512
commit: 0142ec9445a1e45a7d91b6a202b6ad83614b432a [5/7] riscv: errata: Support T-HEAD custom dcache ops
config: riscv-randconfig-r042-20210904 (attached as .config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 6fe2beba7d2a41964af658c8c59dd172683ef739)
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 riscv cross compiling tool for clang build
        # apt-get install binutils-riscv64-linux-gnu
        # https://github.com/c-sky/csky-linux/commit/0142ec9445a1e45a7d91b6a202b6ad83614b432a
        git remote add csky-linux https://github.com/c-sky/csky-linux
        git fetch --no-tags csky-linux linux-5.15-rc1-d1-v4
        git checkout 0142ec9445a1e45a7d91b6a202b6ad83614b432a
        # save the attached .config to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross O=build_dir ARCH=riscv 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 >>):

>> arch/riscv/errata/thead/errata.c:94:36: error: variable has incomplete type 'struct riscv_dma_cache_sync'
   static struct riscv_dma_cache_sync c900_dma_cache_sync = {
                                      ^
   arch/riscv/errata/thead/errata.c:94:15: note: forward declaration of 'struct riscv_dma_cache_sync'
   static struct riscv_dma_cache_sync c900_dma_cache_sync = {
                 ^
>> arch/riscv/errata/thead/errata.c:103:2: error: implicit declaration of function 'riscv_dma_cache_sync_set' [-Werror,-Wimplicit-function-declaration]
           riscv_dma_cache_sync_set(&c900_dma_cache_sync);
           ^
   2 errors generated.


vim +94 arch/riscv/errata/thead/errata.c

    93	
  > 94	static struct riscv_dma_cache_sync c900_dma_cache_sync = {
    95		.cache_invalidate = c900_cache_invalidate,
    96		.cache_clean = c900_cache_clean,
    97		.cache_flush = c900_cache_flush,
    98	};
    99	
   100	void __init thead_errata_patch_func(struct alt_entry *begin, struct alt_entry *end,
   101					     unsigned long archid, unsigned long impid)
   102	{
 > 103		riscv_dma_cache_sync_set(&c900_dma_cache_sync);

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