1 files changed, 16 insertions, 2 deletions

diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
index 322ee56ea1fe..19ef9f018012 100644
--- a/arch/x86/mm/init_32.c
+++ b/arch/x86/mm/init_32.c
@@ -480,9 +480,14 @@ void __init native_pagetable_init(void)
 
         /*
          * Remove any mappings which extend past the end of physical
-         * memory from the boot time page table:
+         * memory from the boot time page table.
+         * In virtual address space, we should have at least two pages
+         * from VMALLOC_END to pkmap or fixmap according to VMALLOC_END
+         * definition. And max_low_pfn is set to VMALLOC_END physical
+         * address. If initial memory mapping is doing right job, we
+         * should have pte used near max_low_pfn or one pmd is not present.
          */
-        for (pfn = max_low_pfn + 1; pfn < 1<<(32-PAGE_SHIFT); pfn++) {
+        for (pfn = max_low_pfn; pfn < 1<<(32-PAGE_SHIFT); pfn++) {
                 va = PAGE_OFFSET + (pfn<<PAGE_SHIFT);
                 pgd = base + pgd_index(va);
                 if (!pgd_present(*pgd))
@@ -493,10 +498,19 @@ void __init native_pagetable_init(void)
                 if (!pmd_present(*pmd))
                         break;
 
+                /* should not be large page here */
+                if (pmd_large(*pmd)) {
+                        pr_warn("try to clear pte for ram above max_low_pfn: pfn: %lx pmd: %p pmd phys: %lx, but pmd is big page and is not using pte !\n",
+                                pfn, pmd, __pa(pmd));
+                        BUG_ON(1);
+                }
+
                 pte = pte_offset_kernel(pmd, va);
                 if (!pte_present(*pte))
                         break;
 
+                printk(KERN_DEBUG "clearing pte for ram above max_low_pfn: pfn: %lx pmd: %p pmd phys: %lx pte: %p pte phys: %lx\n",
+                                pfn, pmd, __pa(pmd), pte, __pa(pte));
                 pte_clear(NULL, va, pte);
         }
         paravirt_alloc_pmd(&init_mm, __pa(base) >> PAGE_SHIFT);