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-a012 
(https://download.01.org/0day-ci/archive/20220319/[email protected]/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project 
a6e70e4056dff962ec634c5bd4f2f4105a0bef71)
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/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
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross 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 <[email protected]>

All warnings (new ones prefixed by >>):

>> arch/x86/mm/pat/set_memory.c:1935:5: warning: no previous prototype for 
>> function 'set_mce_nospec' [-Wmissing-prototypes]
   int set_mce_nospec(unsigned long pfn, bool unmap)
       ^
   arch/x86/mm/pat/set_memory.c:1935:1: note: declare 'static' if the function 
is not intended to be used outside of this translation unit
   int set_mce_nospec(unsigned long pfn, bool unmap)
   ^
   static 
>> arch/x86/mm/pat/set_memory.c:1968:5: warning: no previous prototype for 
>> function 'clear_mce_nospec' [-Wmissing-prototypes]
   int clear_mce_nospec(unsigned long pfn)
       ^
   arch/x86/mm/pat/set_memory.c:1968:1: note: declare 'static' if the function 
is not intended to be used outside of this translation unit
   int clear_mce_nospec(unsigned long pfn)
   ^
   static 
   2 warnings generated.


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  

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