Hi Leonardo,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on powerpc/next]
[also build test ERROR on asm-generic/master paulus-powerpc/kvm-ppc-next linus/master v5.5 next-20200207]
[cannot apply to kvm-ppc/kvm-ppc-next]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]

url:    https://github.com/0day-ci/linux/commits/Leonardo-Bras/Introduces-new-functions-for-tracking-lockless-pagetable-walks/20200207-071035
base:   https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git next
config: xtensa-common_defconfig (attached as .config)
compiler: xtensa-linux-gcc (GCC) 7.5.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        GCC_VERSION=7.5.0 make.cross ARCH=xtensa 

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   include/asm-generic/pgtable.h: Assembler messages:
   include/asm-generic/pgtable.h:1230: Error: unknown opcode or format name 'static'
   include/asm-generic/pgtable.h:1231: Error: unknown opcode or format name 'unsigned'
   include/asm-generic/pgtable.h:1233: Error: unknown opcode or format name 'unsigned'
   include/asm-generic/pgtable.h:1240: Error: unknown opcode or format name 'local_irq_save'
   include/asm-generic/pgtable.h:1248: Error: unknown opcode or format name 'smp_mb'
   include/asm-generic/pgtable.h:1250: Error: unknown opcode or format name 'return'
>> include/asm-generic/pgtable.h:1251: Error: couldn't find a valid instruction format
       ops were: 
   include/asm-generic/pgtable.h:1257: Error: unknown opcode or format name 'static'
   include/asm-generic/pgtable.h:1265: Error: unknown opcode or format name 'smp_mb'
   include/asm-generic/pgtable.h:1272: Error: unknown opcode or format name 'local_irq_restore'
   include/asm-generic/pgtable.h:1273: Error: couldn't find a valid instruction format
       ops were: 

vim +1251 include/asm-generic/pgtable.h

  1224	
  1225	#ifndef __HAVE_ARCH_LOCKLESS_PGTBL_WALK_CONTROL
  1226	/*
  1227	 * begin_lockless_pgtbl_walk: Must be inserted before a function call that does
  1228	 *   lockless pagetable walks, such as __find_linux_pte()
  1229	 */
  1230	static inline
  1231	unsigned long begin_lockless_pgtbl_walk(void)
  1232	{
  1233		unsigned long irq_mask;
  1234	
  1235		/*
  1236		 * Interrupts must be disabled during the lockless page table walk.
  1237		 * That's because the deleting or splitting involves flushing TLBs,
  1238		 * which in turn issues interrupts, that will block when disabled.
  1239		 */
  1240		local_irq_save(irq_mask);
  1241	
  1242		/*
  1243		 * This memory barrier pairs with any code that is either trying to
  1244		 * delete page tables, or split huge pages. Without this barrier,
  1245		 * the page tables could be read speculatively outside of interrupt
  1246		 * disabling.
  1247		 */
  1248		smp_mb();
  1249	
  1250		return irq_mask;
> 1251	}
  1252	

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