tree: https://git.kernel.org/pub/scm/linux/kernel/git/sashal/linux-stable.git queue-5.4 head: b4001462a35a736ae9775784796ae0be700db254 commit: e303fb358e55829f315ac501b46d63808f2fa9d4 [171/194] MIPS: CPU_LOONGSON2EF need software to maintain cache consistency config: mips-allyesconfig (attached as .config) compiler: mips-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 e303fb358e55829f315ac501b46d63808f2fa9d4 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=mips If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All errors (new ones prefixed by >>): arch/mips/mm/dma-noncoherent.c: In function 'cpu_needs_post_dma_flush': 36 | case CPU_LOONGSON2EF: | ^~~~~~~~~~~~~~~ | CPU_LOONGSON2 arch/mips/mm/dma-noncoherent.c:36:7: note: each undeclared identifier is reported only once for each function it appears in vim +36 arch/mips/mm/dma-noncoherent.c 16 17 /* 18 * The affected CPUs below in 'cpu_needs_post_dma_flush()' can speculatively 19 * fill random cachelines with stale data at any time, requiring an extra 20 * flush post-DMA. 21 * 22 * Warning on the terminology - Linux calls an uncached area coherent; MIPS 23 * terminology calls memory areas with hardware maintained coherency coherent. 24 * 25 * Note that the R14000 and R16000 should also be checked for in this condition. 26 * However this function is only called on non-I/O-coherent systems and only the 27 * R10000 and R12000 are used in such systems, the SGI IP28 Indigo² rsp. 28 * SGI IP32 aka O2. 29 */ 30 static inline bool cpu_needs_post_dma_flush(struct device *dev) 31 { 32 switch (boot_cpu_type()) { 33 case CPU_R10000: 34 case CPU_R12000: 35 case CPU_BMIPS5000: 37 return true; 38 default: 39 /* 40 * Presence of MAARs suggests that the CPU supports 41 * speculatively prefetching data, and therefore requires 42 * the post-DMA flush/invalidate. 43 */ 44 return cpu_has_maar; 45 } 46 } 47 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org