+static pte_t *__init page_table_kmap_check(pte_t *pte, pmd_t *pmd,
+ unsigned long vaddr, pte_t *lastpte)
+{
+#ifdef CONFIG_HIGHMEM
+ /*
+ * Something (early fixmap) may already have put a pte
+ * page here, which causes the page table allocation
+ * to become nonlinear. Attempt to fix it, and if it
+ * is still nonlinear then we have to bug.
+ */
+ int pmd_idx_kmap_begin = fix_to_virt(FIX_KMAP_END) >> PMD_SHIFT;
+ int pmd_idx_kmap_end = fix_to_virt(FIX_KMAP_BEGIN) >> PMD_SHIFT;
+
+ if (pmd_idx_kmap_begin != pmd_idx_kmap_end
+ && (vaddr >> PMD_SHIFT) >= pmd_idx_kmap_begin
+ && (vaddr >> PMD_SHIFT) <= pmd_idx_kmap_end
+ && ((__pa(pte) >> PAGE_SHIFT) < table_start
+ || (__pa(pte) >> PAGE_SHIFT) >= table_end)) {
+ pte_t *newpte;
+ int i;
+
+ BUG_ON(after_init_bootmem);
+ newpte = alloc_low_page();
+ for (i = 0; i < PTRS_PER_PTE; i++)
+ set_pte(newpte + i, pte[i]);
+
+ paravirt_alloc_pte(&init_mm, __pa(newpte) >> PAGE_SHIFT);
+ set_pmd(pmd, __pmd(__pa(newpte)|_PAGE_TABLE));
+ BUG_ON(newpte != pte_offset_kernel(pmd, 0));
+ __flush_tlb_all();
+
+ paravirt_release_pte(__pa(pte) >> PAGE_SHIFT);
+ pte = newpte;
+ }
+ BUG_ON(vaddr < fix_to_virt(FIX_KMAP_BEGIN - 1)
+ && vaddr > fix_to_virt(FIX_KMAP_END)
+ && lastpte && lastpte + PTRS_PER_PTE != pte);
+#endif
+ return pte;
+}
+