+extern void *kmap_high_l1_vipt(struct page *page, pte_t *saved_pte);
+extern void kunmap_high_l1_vipt(struct page *page, pte_t saved_pte);
+
+/*
+ * The following functions are already defined by <linux/highmem.h>
+ * when CONFIG_HIGHMEM is not set.
+ */
+#ifdef CONFIG_HIGHMEM
extern void *kmap(struct page *page);
extern void kunmap(struct page *page);
extern void *kmap_atomic(struct page *page, enum km_type type);
extern void kunmap_atomic(void *kvaddr, enum km_type type);
extern void *kmap_atomic_pfn(unsigned long pfn, enum km_type type);
extern struct page *kmap_atomic_to_page(const void *ptr);
extern void *kmap(struct page *page);
extern void kunmap(struct page *page);
extern void *kmap_atomic(struct page *page, enum km_type type);
extern void kunmap_atomic(void *kvaddr, enum km_type type);
extern void *kmap_atomic_pfn(unsigned long pfn, enum km_type type);
extern struct page *kmap_atomic_to_page(const void *ptr);