Re: [PATCH 10/26] mm: asi: Avoid warning from NMI userspace accesses in ASI context

[kernel test robot <lkp@intel.com>]

Hi Brendan,

kernel test robot noticed the following build warnings:

[auto build test WARNING on a38297e3fb012ddfa7ce0321a7e5a8daeb1872b6]

url:    https://github.com/intel-lab-lkp/linux/commits/Brendan-Jackman/mm-asi-Make-some-utility-functions-noinstr-compatible/20240713-012107
base:   a38297e3fb012ddfa7ce0321a7e5a8daeb1872b6
patch link:    https://lore.kernel.org/r/20240712-asi-rfc-24-v1-10-144b319a40d8%40google.com
patch subject: [PATCH 10/26] mm: asi: Avoid warning from NMI userspace accesses in ASI context
config: i386-buildonly-randconfig-004-20240714 (https://download.01.org/0day-ci/archive/20240714/202407141109.Vpmj3Sze-lkp@intel.com/config)
compiler: clang version 18.1.5 (https://github.com/llvm/llvm-project 617a15a9eac96088ae5e9134248d8236e34b91b1)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240714/202407141109.Vpmj3Sze-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202407141109.Vpmj3Sze-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> arch/x86/mm/tlb.c:1329:20: warning: function 'cr3_matches_current_mm' is not needed and will not be emitted [-Wunneeded-internal-declaration]
    1329 | static inline bool cr3_matches_current_mm(void)
         |                    ^~~~~~~~~~~~~~~~~~~~~~
   1 warning generated.


vim +/cr3_matches_current_mm +1329 arch/x86/mm/tlb.c

  1328	
> 1329	static inline bool cr3_matches_current_mm(void)
  1330	{
  1331		struct asi *asi = asi_get_current();
  1332		pgd_t *cr3_pgd;
  1333	
  1334		/*
  1335		 * Prevent read_cr3_pa -> [NMI, asi_exit] -> asi_get_current,
  1336		 * otherwise we might find CR3 pointing to the ASI PGD but not
  1337		 * find a current ASI domain.
  1338		 */
  1339		barrier();
  1340		cr3_pgd = __va(read_cr3_pa());
  1341	
  1342		if (cr3_pgd == current->mm->pgd)
  1343			return true;
  1344		return asi && (cr3_pgd == asi_pgd(asi));
  1345	}
  1346	

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