Hi Jane, Thank you for the patch! Perhaps something to improve: [auto build test WARNING on nvdimm/libnvdimm-for-next] [also build test WARNING on device-mapper-dm/for-next linus/master v5.17-rc8 next-20220318] [cannot apply to tip/x86/mm] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch] url: https://github.com/0day-ci/linux/commits/Jane-Chu/DAX-poison-recovery/20220319-143144 base: https://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm.git libnvdimm-for-next config: x86_64-randconfig-a015 (https://download.01.org/0day-ci/archive/20220319/202203191637.PK2oJUeq-lkp@xxxxxxxxx/config) compiler: gcc-9 (Ubuntu 9.4.0-1ubuntu1~20.04) 9.4.0 reproduce (this is a W=1 build): # https://github.com/0day-ci/linux/commit/71b9b09529b207ce15667c1f5fba4b727b6754e6 git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Jane-Chu/DAX-poison-recovery/20220319-143144 git checkout 71b9b09529b207ce15667c1f5fba4b727b6754e6 # save the config file to linux build tree mkdir build_dir make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash arch/x86/mm/pat/ fs/fuse/ If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp@xxxxxxxxx> All warnings (new ones prefixed by >>): >> arch/x86/mm/pat/set_memory.c:1935:5: warning: no previous prototype for 'set_mce_nospec' [-Wmissing-prototypes] 1935 | int set_mce_nospec(unsigned long pfn, bool unmap) | ^~~~~~~~~~~~~~ >> arch/x86/mm/pat/set_memory.c:1968:5: warning: no previous prototype for 'clear_mce_nospec' [-Wmissing-prototypes] 1968 | int clear_mce_nospec(unsigned long pfn) | ^~~~~~~~~~~~~~~~ vim +/set_mce_nospec +1935 arch/x86/mm/pat/set_memory.c 1927 1928 #ifdef CONFIG_X86_64 1929 /* 1930 * Prevent speculative access to the page by either unmapping 1931 * it (if we do not require access to any part of the page) or 1932 * marking it uncacheable (if we want to try to retrieve data 1933 * from non-poisoned lines in the page). 1934 */ > 1935 int set_mce_nospec(unsigned long pfn, bool unmap) 1936 { 1937 unsigned long decoy_addr; 1938 int rc; 1939 1940 /* SGX pages are not in the 1:1 map */ 1941 if (arch_is_platform_page(pfn << PAGE_SHIFT)) 1942 return 0; 1943 /* 1944 * We would like to just call: 1945 * set_memory_XX((unsigned long)pfn_to_kaddr(pfn), 1); 1946 * but doing that would radically increase the odds of a 1947 * speculative access to the poison page because we'd have 1948 * the virtual address of the kernel 1:1 mapping sitting 1949 * around in registers. 1950 * Instead we get tricky. We create a non-canonical address 1951 * that looks just like the one we want, but has bit 63 flipped. 1952 * This relies on set_memory_XX() properly sanitizing any __pa() 1953 * results with __PHYSICAL_MASK or PTE_PFN_MASK. 1954 */ 1955 decoy_addr = (pfn << PAGE_SHIFT) + (PAGE_OFFSET ^ BIT(63)); 1956 1957 if (unmap) 1958 rc = set_memory_np(decoy_addr, 1); 1959 else 1960 rc = set_memory_uc(decoy_addr, 1); 1961 if (rc) 1962 pr_warn("Could not invalidate pfn=0x%lx from 1:1 map\n", pfn); 1963 return rc; 1964 } 1965 EXPORT_SYMBOL(set_mce_nospec); 1966 1967 /* Restore full speculative operation to the pfn. */ > 1968 int clear_mce_nospec(unsigned long pfn) 1969 { 1970 return set_memory_wb((unsigned long) pfn_to_kaddr(pfn), 1); 1971 } 1972 EXPORT_SYMBOL(clear_mce_nospec); 1973 --- 0-DAY CI Kernel Test Service https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx
