+#ifdef CONFIG_PAGE_POISONING
+extern bool page_poisoning_enabled(void);
+extern void kernel_poison_pages(struct page *page, int numpages, int enable);
+extern bool page_is_poisoned(struct page *page);
+#else
+static inline bool page_poisoning_enabled(void) { return false; }
+static inline void kernel_poison_pages(struct page *page, int numpages,
+ int enable) { }
+static inline bool page_is_poisoned(struct page *page) { return false; }
+#endif
+