Hi Anthony,

[FYI, it's a private test report for your RFC patch.]
[auto build test ERROR on tip/x86/mm]
[also build test ERROR on tip/auto-latest linus/master v5.7-rc5]
[cannot apply to tip/x86/core next-20200512]
[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/Anthony-Yznaga/PKRAM-Preserved-over-Kexec-RAM/20200507-084926
base:   https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git bd1de2a7aace4d1d312fb1be264b8fafdb706208
config: microblaze-randconfig-r005-20200512 (attached as .config)
compiler: microblaze-linux-gcc (GCC) 9.3.0
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
        COMPILER_INSTALL_PATH=$HOME/0day GCC_VERSION=9.3.0 make.cross ARCH=microblaze 

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

All errors (new ones prefixed by >>):

microblaze-linux-ld: mm/shmem.o: in function `shmem_add_aligned_to_page_cache':
>> mm/shmem.c:803: undefined reference to `xas_import_node'

vim +803 mm/shmem.c

   734	
   735	static int shmem_add_aligned_to_page_cache(struct page *pages[], int npages,
   736						   struct address_space *mapping,
   737						   pgoff_t index, gfp_t gfp, int order)
   738	{
   739		int xa_shift = order + XA_CHUNK_SHIFT - (order % XA_CHUNK_SHIFT);
   740		XA_STATE_ORDER(xas, &mapping->i_pages, index, xa_shift);
   741		struct xa_state *xas_ptr = &xas;
   742		struct xarray xa_tmp;
   743		/*
   744		 * Specify order so xas_create_range() only needs to be called once
   745		 * to allocate the entire range.  This guarantees that xas_store()
   746		 * will not fail due to lack of memory.
   747		 * Specify index == 0 so the minimum necessary nodes are allocated.
   748		 */
   749		XA_STATE_ORDER(xas_tmp, &xa_tmp, 0, xa_shift);
   750		unsigned long nr = 1UL << order;
   751		struct xa_node *node;
   752		int i;
   753	
   754		if (npages * nr != 1 << xa_shift) {
   755			WARN_ONCE(1, "npages (%d) not aligned to xa_shift\n", npages);
   756			return -EINVAL;
   757		}
   758		if (!IS_ALIGNED(index, 1 << xa_shift)) {
   759			WARN_ONCE(1, "index (%lu) not aligned to xa_shift\n", index);
   760			return -EINVAL;
   761		}
   762	
   763		for (i = 0; i < npages; i++) {
   764			VM_BUG_ON_PAGE(PageTail(pages[i]), pages[i]);
   765			VM_BUG_ON_PAGE(!PageLocked(pages[i]), pages[i]);
   766			VM_BUG_ON_PAGE(!PageSwapBacked(pages[i]), pages[i]);
   767	
   768			page_ref_add(pages[i], nr);
   769			pages[i]->mapping = mapping;
   770			pages[i]->index = index + (i * nr);
   771		}
   772	
   773		xa_init(&xa_tmp);
   774		do {
   775			xas_lock(&xas_tmp);
   776			xas_create_range(&xas_tmp);
   777			if (xas_error(&xas_tmp))
   778				goto unlock;
   779			for (i = 0; i < npages; i++) {
   780				int j = 0;
   781	next:
   782				xas_store(&xas_tmp, pages[i]);
   783				if (++j < nr) {
   784					xas_next(&xas_tmp);
   785					goto next;
   786				}
   787				if (i < npages - 1)
   788					xas_next(&xas_tmp);
   789			}
   790			xas_set_order(&xas_tmp, 0, xa_shift);
   791			node = xas_export_node(&xas_tmp);
   792	unlock:
   793			xas_unlock(&xas_tmp);
   794		} while (xas_nomem(&xas_tmp, gfp));
   795	
   796		if (xas_error(&xas_tmp)) {
   797			xas_ptr = &xas_tmp;
   798			goto error;
   799		}
   800	
   801		do {
   802			xas_lock_irq(&xas);
 > 803			xas_import_node(&xas, node);
   804			if (xas_error(&xas))
   805				goto unlock1;
   806			mapping->nrpages += nr * npages;
   807			xas_unlock(&xas);
   808			for (i = 0; i < npages; i++) {
   809				__mod_node_page_state(page_pgdat(pages[i]), NR_FILE_PAGES, nr);
   810				__mod_node_page_state(page_pgdat(pages[i]), NR_SHMEM, nr);
   811				if (PageTransHuge(pages[i])) {
   812					count_vm_event(THP_FILE_ALLOC);
   813					__inc_node_page_state(pages[i], NR_SHMEM_THPS);
   814				}
   815			}
   816			local_irq_enable();
   817			break;
   818	unlock1:
   819			xas_unlock_irq(&xas);
   820		} while (xas_nomem(&xas, gfp));
   821	
   822		if (!xas_error(&xas))
   823			return 0;
   824	
   825	error:
   826		for (i = 0; i < npages; i++) {
   827			pages[i]->mapping = NULL;
   828			page_ref_sub(pages[i], nr);
   829		}
   830		return xas_error(xas_ptr);
   831	}
   832	

---
0-DAY CI Kernel Test Service, Intel Corporation
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